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Graphene Oxide–based Biomaterials in Sports Medicine

Mengran Xi^1,a, Renwen Wan^1,2,3,a, Wei Luo^1,2,3,a, Yanwei He^1,2, Xinting Feng^1,2, Tianqi Wang⁴, Jiajun Qiu^5,*, Shiyi Chen^1,2,3,* and Zhiwen Luo^{1,2,3,4,6,7,*}

¹Fudan University – Dr. Kong Joint Research Center for Sports Medicine and Health Footwear, Fudan University Institute of Sports Medicine (Jinqiao Laboratory), Shanghai, China

²Department of Sports Medicine, Huashan Hospital, Fudan University, Shanghai, China

³Fudan Zhangjiang Institute, Fudan University, Shanghai, China

⁴Department of Orthopaedic Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore

⁵State Key Laboratory of High Performance Ceramics, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China

⁶Department of Orthopaedics, Jiaxing Key Laboratory of Basic Research and Clinical Translation on Orthopedic Biomaterials, The Second Affiliated Hospital of Jiaxing University (Sports Hospital of Jiaxing), 1518 North Huancheng Road, Jiaxing 314000, China

⁷Department of Orthopedics, Ward 5, 11th Floor, Surgery Building, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, 305 Zhongshan East Road, Xuanwu District Nanjing, Jiangsu Province 210002, China

^aThese authors make equal contributions to this work.

*Correspondence to: Jiajun Qiu, Ph.D., Associate Professor of State Key Laboratory of High Performance Ceramics, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China. E-mail: qiujiajun@mail.sic.ac.cn; Shiyi Chen, Ph.D., Director of Department of Sports Medicine, Huashan Hospital, Chairman of the Chinese Society of Sports Medicine, Fudan University, 12# MiddleWulumuqi Road, Jing’an District, Shanghai 200040, China. E-mail: cshiyi@163.com; Zhiwen Luo, BSc (Hons), M.D., Ph.D., Academic Director of Sports Hospital of Jiaxing, Academic Director, Fudan University – Dr. Kong Joint Research Center for Sports Medicine and Health Footwear, Department of Sports Medicine, Huashan Hospital, Fudan University, No. 12 Wulumuqi Zhong Road, Shanghai, China. E-mail: zhiwen.luo_fudan@hotmail.com

Received: October 4 2025; Revised: December 11 2025; Accepted: January 6 2026; Published Online: March 9 2026

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Cite this paper:

Xi M, Wan R, Luo W et al. Graphene Oxide–based Biomaterials in Sports Medicine. BIO Integration 2026; 7: 1–20.

DOI: 10.15212/bioi-2025-0172. Available at: https://bio-integration.org/

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© 2026 The Authors. This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). See https://bio-integration.org/copyright-and-permissions/

Abstract

This review summarizes recent advances in the application of graphene oxide (GO) in sports medicine with an emphasis on cartilage repair, skeletal muscle regeneration, ligament and tendon repair, and tendon–bone (enthesis) healing. Owing to the distinctive physicochemical properties and favorable biocompatibility, GO exhibits considerable promise across these indications. We first outline the chemical structure and physical characteristics of GO, then discuss mechanistic roles that underpin the performance of GO in different disease contexts. We further synthesize evidence that GO strengthens biomaterials mechanically and enhances cellular adhesion and lineage commitment, which promotes tenogenic, chondrogenic, and myogenic differentiation. as well as enthesis formation. Despite these advantages, important questions remain regarding the biosafety and long-term in vivo stability of GO. Future work should prioritize rational chemical functionalization and composite design to tailor GO-based materials to specific tissue-repair requirements with the development of next-generation GO scaffolds that better recapitulate the human biomechanical milieu. In parallel, multi-omics interrogation of GO–cell interactions will deepen our mechanistic understanding and guide material optimization. Addressing these key challenges will enable GO to have a larger role in cartilage repair and sports medicine, accelerating progress in the field.

Keywords

Biomaterials; composite scaffolds; graphene oxide (GO); skeletal muscle regeneration; sports medicine; tendon and ligament regeneration; tendon–bone (enthesis) healing.

Introduction

Graphene, a single atomic layer of sp²-hybridized carbon atoms arranged in a honeycomb lattice, is an exceptional material. Graphene exhibits the following outstanding electrochemical and transport properties: an ultra-high thermal conductivity, reportedly up to one million times greater than copper [1, 2]; a low redox potential typically ranging from −0.5 to 1.2 V; broadband optical absorption that extends into the infrared; and complete impermeability to all gases. Graphene also offers an extraordinarily large specific surface area (up to 2630 m² g⁻¹) and remarkable mechanical strength (~1100 GPa) [3–5]. These features underpin wide-ranging prospects in electronics and biomedicine.

Graphene derivatives have attracted intense attention over the past decade because of the anticipated translational potential. Among the graphene derivatives, graphene oxide (GO), a two-dimensional material produced by chemical oxidation, has emerged as a focal point in biomedicine. Abundant oxygenated functional groups (e.g., hydroxyl, carboxyl, and epoxide) are embedded within the GO lattice, which endows GO with distinctive chemical reactivity and physical behavior [6–8]. GO combines high mechanical robustness and large surface area with advantageous thermal and electrical attributes, making GO promising for drug delivery, biosensing, and tissue engineering applications [9, 10]. Notably, further processing yields reduced graphene oxide (rGO) or functionalized graphene oxide (FGO), enabling tailored performance and improved biocompatibility for specific use [9, 11, 12]. With continued advances, GO and GO derivatives are expected to have increasingly broad biomedical deployment.

Sports medicine focuses on the prevention and treatment of exercise-related injuries [13, 14], encompassing clinical care, rehabilitation, nutrition, and performance optimization. Sports medicine interrogates physiologic responses to exercise and mechanisms of tissue repair to enhance health and athletic capacity, especially within muscle, bone, joints, ligaments, and tendons (Figure 1) [15–17]. Successful tissue repair in sports medicine typically relies on four pillars: (1) appropriate reparative cells capable of regenerating or replacing damaged tissue; (2) a supportive microenvironment, often provided by a scaffold; (3) relevant biomolecules, such as growth factors that drive proliferation and matrix synthesis; and (4) mechanical cues within the physical microenvironment that guide maturation of the new tissue [18–20]. Biocompatible and tunable biomaterials have therefore drawn substantial interest for the capacity to promote regeneration and wound healing [18–21] and identifying clinically deployable materials has become a central objective [22–24].

Compared to traditional biomaterials, such as poly (lactic-co-glycolic acid) [PLGA] or natural polymers (e.g., collagen and alginate), GO-based materials offer a unique combination of advantages [25]. While traditional polymer scaffolds possess good biocompatibility, traditional polymer scaffolds often lack sufficient mechanical strength for load-bearing tissues, like cartilage, and have limited bioactivity [26]. Conversely, metallic or ceramic implants, although robust, lack biodegradability and have a severe modulus mismatch with biological tissues, which potentially causes stress-shielding [27]. The incorporation of GO can significantly enhance the mechanical properties of composite materials at very low concentrations, bringing composite materials closer to the mechanical requirements of native tissues [28]. More importantly, the unique surface chemistry and electrical conductivity of GO provide the material with unprecedented bio-functionality to actively guide cell behavior and tissue regeneration, an attribute often missing in conventional materials [29].

Within this context, GO shows compelling potential for repairing and reconstructing the musculoskeletal system, particularly in cartilage, tendon, ligament, and bone-related injuries. The mechanical strength, electrical conductivity, and thermal stability of GO, coupled with unique biological functions and generally favorable compatibility, make GO an attractive candidate material in sports medicine [1–3]. Nevertheless, opportunities come with challenges. Key issues remain regarding biosafety, precise control of cell–material interactions, and in vivo stability and degradability [6–8]. Thus, despite encouraging prospects, rigorous mechanistic studies and extensive preclinical and clinical testing are still required for translation in sports medicine. Notably, GO serves as a versatile platform for chemical modification, yielding derivatives with properties tailored for specific applications [30]. The most common modification strategy is reduction, which produces rGO. By removing many of the oxygen-containing functional groups, this process partially restores the excellent electrical conductivity of graphene, making rGO particularly promising for the regeneration of electroactive tissues, such as skeletal muscle or nerves [11]. Another key strategy is surface functionalization, in which specific biomolecules (e.g., peptides and growth factors) are attached to the GO surface via covalent or non-covalent bonds [11]. This approach creates materials with enhanced biological specificity, enabling more precise targeting of cells or the controlled release of therapeutic agents to trigger distinct biological pathways. Therefore, this review will not only focus on GO but will also, where appropriate, explore how these key derivatives (rGO and various functionalized GO materials) provide unique solutions to specific challenges in sports medicine. This review synthesizes recent progress on GO-based biomaterials across sports medicine applications to provide guidance and perspective for future research.

Fundamental properties of GO

Chemical structure and physical features

GO possesses a distinctive architecture in which carbon atoms are connected through mixed sp²/sp³ hybridization to form a planar hexagonal network. Abundant oxygen-containing functional groups (primarily hydroxyl, carboxyl, and epoxide moieties) are interspersed on the basal plane and enriched at sheet edges, collectively dictating the reactivity, dispersibility, and interfacial behavior of GO.

Production process

GO is most frequently produced via the Hummers route [31–35]. Briefly, graphite flakes are oxidized under strongly acidic conditions. Graphite is dispersed and cooled to ~5°C in concentrated sulfuric acid, then oxidized using KMnO₄ and K₂FeO₄ for ~1.5 h, followed by further (deep) oxidation with KMnO₄. The oxidized material is hydrolyzed with deionized water at 95°C for 15 min, yielding a brown suspension indicative of exfoliated graphite oxide. Residual oxidants and sulfate intermediates are quenched with H₂O₂ and the product is repeatedly washed with hydrochloric acid and water to remove ionic by-products and obtain purified GO (Figure 2).

Physical properties

Disruption of the pristine sp² network imparts GO with pronounced electrical insulation. Depending on the degree of oxidation and reduction state, semiconducting behavior can also emerge. GO exhibits a high specific surface area (up to ~890 m² g⁻¹) together with robust mechanics, which is an effective Young’s modulus on the order of ~1.0 TPa and a fracture strength approaching ~130 GPa [8, 36–38]. These mechanical attributes are critically important for sports medicine applications and enable GO to serve as a highly effective nanofiller that can significantly enhance the mechanical strength and toughness of hydrogels or polymer scaffolds, even at low concentrations, allowing the hydrogels or polymer scaffolds to withstand the physiologic loads experienced by load-bearing tissues, like articular cartilage or tendons [39].

Surface hydrophilicity

Oxidation converts hydrophobic graphene into hydrophilic GO by introducing hydroxyl, epoxide, and other polar functionalities (primarily carboxyl and carbonyl groups) on the basal plane and sheet edges. These oxygenated groups enable stable dispersion in water and other polar solvents and provide versatile handles for surface chemistry and bioconjugation, facilitating the coupling of proteins, antibodies, and nucleic acids, as well as other bioactive molecules such as growth factors and peptides [6, 8, 40]. This hydrophilicity and abundance of functional groups are particularly advantageous in tissue engineering as the functional groups not only promote the integration of the scaffold material within the aqueous biological environment (Figure 3) but also serve as “anchors” for immobilizing growth factors or adhesion proteins, thereby creating a bioactive microenvironment that can actively guide stem cell differentiation.

Adsorption and interaction mechanisms

GO exhibits strong adsorption toward proteins and antibodies, which can help preserve adsorbates from degradation and is an advantage for protein delivery and biosensing platforms [41, 42]. Protein binding to GO is mediated by multiple non-covalent forces, including hydrophobic interactions, van der Waals forces, electrostatic attraction/repulsion, and hydrogen bonding. Adsorption behavior can shift from Freundlich- to Langmuir-type isotherms as the degree of oxidation increases, reflecting changes in surface heterogeneity and site saturation [43]. The π-electron-rich basal plane also enables π–π stacking with hydrophobic drugs and polymers, supporting the formation of nanocomposites. In addition, covalent conjugation of biomolecules to GO via reactive oxygenated groups can enhance conjugate stability across diverse environments, although care must be taken because covalent coupling can alter protein conformation and function; the use of appropriate crosslinkers can mitigate such effects [7, 44].

The tunable chemistry of GO, large surface area, and high mechanical strength, render GO broadly applicable across biomedicine, including tissue engineering, drug delivery, and biosensing. The ability of GO to form stable aqueous dispersions, present multifunctional binding sites, and undergo controlled chemical modification creates a flexible platform for engineering next-generation bio-interfaces and therapeutic systems.

Biocompatibility

The widespread biomedical use of GO is largely attributable to the favorable biocompatibility. Numerous studies have shown that GO supports the adhesion and proliferation of diverse cell types, including osteoblasts and neurons, making GO an attractive component for tissue-engineered scaffolds [45–49]. Nevertheless, uncertainties remain regarding cytotoxicity and long-term in vivo compatibility and outcomes can vary with production routes and post-processing (e.g., chemical functionalization or physical modification) that modulate surface chemistry and biological responses. Because graphene-based nanomaterials may elicit cytotoxicity and challenge biocompatibility in vivo, GO and GO derivatives must be evaluated in the context of the physicochemical attributes and interactions with the biological milieu.

Cytotoxicity

Biocompatibility is pivotal in determining the in vivo behavior and toxicity profile of nanomaterials. Given the diversity of nano–bio interfaces, intrinsic toxicologic effects are heterogeneous and cannot be generalized. Hydrophobicity and aggregation are key determinants for graphene family materials. Pristine graphene tends to irreversibly aggregate in culture media, causing dose- and time-dependent physical damage to cell membranes and resultant cytotoxicity. By contrast, GO and rGO are more hydrophilic and disperse more readily, which generally lowers cytotoxicity relative to pristine graphene [44, 50]. Although oxygenated surface groups on GO/rGO can promote reactive oxygen species (ROS) generation, improved dispersion markedly reduces aggregation-driven physical injury. Therefore, overall cytotoxicity of GO/rGO is typically lower than pristine graphene once synthetic residues are thoroughly removed. Meticulous purification to eliminate chemical by-products from synthesis is therefore essential to minimize cytotoxicity.

Green synthesis approaches

Greener synthetic strategies have been developed to reduce harmful residuals using biocompatible surfactants and reducing agents to indirectly improve biocompatibility [51]. For example, a trastuzumab-modified, dual-functional graphene nanosheet showed good biocompatibility and supported 3D spheroid growth of human breast cancer cells, illustrating the potential of biofriendly surface chemistry to mitigate toxicity while enabling function [52]. However, in addition to the initial material purity, the long-term biosafety of GO critically depends on degradation and clearance within the body.

Hemocompatibility and immune interactions

Blood–material interactions are critical determinants of in vivo biocompatibility. Pristine graphene, rGO, and GO induce dose-dependent hemolysis with pristine graphene typically showing the strongest hemolytic activity. Pre-incubation with proteins and other surface modifications (such as PEGylation or polymer coating) can substantially diminish this risk [53]. Graphene-based materials may also trigger immune responses, including the release of pro-inflammatory cytokines, such as interleukin-6 (IL-6) and IL-8, and activation of complement pathways that contribute to inflammation and potential chronic sequelae. Notably, macrophages and neutrophils internalize GO more efficiently than hydrophobic graphene, which may influence tissue healing and immune modulation [54]. The interaction between GO and the immune system is a “double-edged sword” [55]. Improper physicochemical properties (e.g., large size and sharp edges) can activate inflammasome pathways, leading to pyroptosis and persistent inflammation [56], while well-designed GO materials can be harnessed for beneficial immunomodulation, as mentioned previously. The net outcome of this interaction is highly dependent on the physicochemical parameters of GO, including lateral size, number of layers, surface charge, and degree of functionalization [57]. For example, smaller, surface-functionalized GO nanosheets tend to exhibit better biocompatibility and lower immunogenicity [58]. Therefore, understanding and precisely controlling the structure-activity relationship between these parameters and the immune response is key to the safe and effective application of GO [55].

In vivo biocompatibility

The biodistribution and fate of graphene nanomaterials are governed by the physicochemical properties and exposure routes. These materials can traverse biological barriers, accumulate in organs, and provoke inflammation or tissue injury [6, 45]. High-dose GO has been shown to cause severe, persistent pulmonary damage in mice, while few-layer graphene accumulates primarily in the lungs after injection, with possible redistribution to the liver and spleen [59]. GO accumulation in organs, such as the spleen, may exert limited histopathologic or functional impact over the long term; some studies report altered T-cell subsets and reduced pro-inflammatory cytokine expression following GO exposure [10]. Designing locally confined, controllable GO-derived materials can restrict systemic accumulation and potential toxicity, thereby broadening applicability, an approach reflected in the growing portfolio of GO-based biomaterials [11, 60, 61].

Recent studies have established specific thresholds for dosage and metabolic kinetics to provide a more quantitative understanding of the biosafety profile. In vitro studies suggested that GO exhibits dose-dependent toxicity with cell viability typically remaining unaffected at concentrations <20 μg/mL, while concentrations >50 μg/mL often induce significant apoptosis [62, 63]. Intravenous administration in mice indicated that a dose of 1–2 mg/kg body weight is generally well-tolerated without acute toxicity, whereas doses >10 mg/kg can lead to pulmonary granuloma formation or organ failure [64]. Furthermore, the pharmacokinetics of GO are strictly governed by the lateral size [65]. Small-sized GO sheets (<50 nm) are rapidly cleared through renal filtration with a blood circulation half-life <1 h, whereas larger sheets are predominantly sequestered by the reticuloendothelial system (RES), primarily in the liver and spleen, where the larger sheets may be retained for > 3 months before gradual clearance [66].

In addition to biodistribution, the GO degradation and clearance mechanisms are critical to long-term safety. Studies have shown that GO is not entirely non-biodegradable. GO can be degraded by specific enzymes in a biological environment [67]. For example, myeloperoxidase (MPO), an enzyme secreted by immune cells, like neutrophils, can effectively catalyze the degradation of GO in the presence of hydrogen peroxide (H₂O₂) [68]. This process breaks down GO into smaller, soluble fragments that can be cleared from the body, potentially via the renal system [69]. The rate of degradation is influenced by the size, degree of oxidation, and surface chemistry of the GO sheets [69–71]. Therefore, a rational design of the physicochemical parameters of GO holds promise for achieving controllable degradation behavior, thereby minimizing long-term accumulation and potential risks in vivo.

Bioactivity

Chemical functionalization is a powerful lever for enhancing both biocompatibility and bioactivity. Peptides and other biomolecules grafted onto GO can strengthen cell–material interactions and direct specific cell behaviors, including lineage commitment [72, 73]. In addition, GO’s large surface area and amenability to modification make it a versatile carrier in drug-delivery systems, capable of loading and controlled release of a broad range of bioactive agents [9].

Collectively, thanks to its unique chemistry, tunable surface, and generally favorable biocompatibility, GO is a multifunctional platform with substantial promise in biomedicine. Nevertheless, successful translation requires deeper interrogation of potential challenges, especially cytotoxicity drivers, immune interactions, biodistribution, and long-term stability, and the development of standardized, application-specific purification and functionalization workflows to ensure safety and efficacy in vivo.

Mechanisms of GO-mediated cellular modulation

The regenerative efficacy of GO-based biomaterials extends beyond the role as passive structural scaffolds. The regenerative efficacy of GO-based biomaterials is fundamentally driven by dynamic physicochemical interactions at the material-cell interface [74]. Understanding these mechanisms is crucial for elucidating how GO directs cell fate, as follows: 1) surface chemistry and the protein corona – The high surface energy and abundant oxygen-containing functional groups (e.g., hydroxyl and carboxyl groups) on GO nanosheets facilitate the rapid adsorption of proteins from the biological environment [75]. This formation of a “protein corona,” which is often enriched with adhesive proteins like, fibronectin, serves as the primary biological interface [75]. The primary biological interface bridges the inorganic material and the cell, directly modulating integrin binding and subsequent focal adhesion formation. 2) mechanotransduction and topography – Cells are highly sensitive to the physical cues of the microenvironment [76]. The unique nanotopography of GO is characterized by ridges, ripples, and edges. When combined with tunable stiffness, the GO nanotopography exerts physical forces on the cytoskeleton [77]. These mechanical stimuli are transduced intracellularly, notably triggering the nuclear translocation of mechanosensors, such as YAP/TAZ [78]. This process translates physical cues into biochemical signals that regulate gene expression related to proliferation and differentiation [79]. 3) ROS scavenging and microenvironment regulation – While high concentrations of GO can induce oxidative stress, controlled amounts of GO and GO derivatives (especially rGO) exhibit enzyme-mimetic properties [80]. This capability allows for the scavenging of excessive ROS, thereby protecting cells from oxidative damage and creating a permissive microenvironment for tissue regeneration.

Collectively, these surface, mechanical, and chemical interactions converge to activate canonical signaling pathways, such as Wnt/β-catenin, TGF-β/Smad, and MAPK/ERK, which ultimately dictate the lineage commitment of stem cells and the functional restoration of tissues [81–83].

Applications of GO in sports medicine

Overview: multifunctional applications of GO in musculoskeletal tissue engineering

The unique physicochemical properties of GO, including exceptional mechanical strength, vast specific surface area, tunable electrical conductivity, and abundant surface chemistry, render GO a highly promising and versatile platform for addressing key challenges in sports medicine and orthopedic tissue engineering [84]. This chapter will explore the specific applications of GO across a range of musculoskeletal regeneration contexts, beginning by examining the role of GO in cartilage repair, in which GP is primarily leveraged as a mechanical reinforcing agent and a carrier for bioactive molecules to create functional scaffolds (Section 3.2) [26]. Subsequently, the use of GO in skeletal muscle regeneration will be investigated, focusing on how electrical conductivity and nanotopography are critical for guiding the formation and maturation of electroactive muscle tissue (Section 3.3) [85]. The discussion will then extend to ligament and tendon repair, highlighting how GO can enhance the toughness and load-bearing capacity of engineered constructs for high-strain environments (Section 3.4) [86]. In addition to the structural roles of GO, the capacity of GO as a bioactive modulator in regulating post-traumatic inflammation will be explored, in which antioxidant and immunomodulatory properties can steer the injury microenvironment toward a pro-reparative state (Section 3.5) [87]. Finally, the complex challenge of tendon–bone healing will be addressed, illustrating how GO-based strategies facilitate the recreation of a functional enthesis by providing mechanical stability, directing cell differentiation, and controlling growth factor release (Table 1) (Section 3.6) [88]. Collectively, these applications demonstrate that GO is evolving from a passive scaffold material into an active, multifunctional component in advanced regenerative strategies for sports-related injuries.

GO in cartilage injury repair

Articular cartilage has negligible intrinsic regenerative capacity, making durable repair challenging and complicating management of cartilage-related disorders, such as osteoarthritis [89–92]. Tissue engineering has therefore emerged as a promising route. Incorporating graphene-based materials into cartilage scaffolds can markedly enhance electrical conductivity and mechanical robustness, leveraging the electro-mechanical attributes of graphene [93–97].

To achieve effective chondral regeneration, investigators have explored GO and GO-containing bio-composites to direct mesenchymal stem cells (MSCs) toward chondrogenesis with encouraging results [98–100]. GO augments chondrogenic differentiation efficiency and higher scaffold porosity, which increases GO loading, can further accelerate lineage commitment [98–100]. GO is frequently combined with biocompatible polymers (e.g., polyvinyl alcohol and chitosan) in cartilage repair to form nanocomposite hydrogels that mimic cartilage extracellular matrix (ECM). These composites exhibit cytocompatibility, responsiveness to external stimuli, and favorable biomechanics. GO incorporation significantly strengthens the matrix and improves durability, which is critical for load-bearing cartilage (Table 2) [95]. Moreover, the surface functional groups of GO interact with bioactive molecules (e.g., proteins and growth factors), promoting stem-cell adhesion and growth [47]. Such composites support cell proliferation and stimulate production of cartilage-specific macromolecules, including collagens and proteoglycans, which are essential for hyaline cartilage formation.

Mechanistically, GO nanosheets can adsorb transforming growth factor (TGF)-β and fibronectin, while preserving the bioactive conformations, which are key to driving chondrogenesis [47]. In addition to single-component systems, hybrid nanocomposites pair GO with other nanoparticles to boost mechanics. For example, GO–chitosan scaffolds combine GO reinforcement with chitosan biocompatibility and have been shown to stimulate proliferation and improve morphology of human articular chondrocytes [101, 102]. Additional GO-based combinations, such as with polyvinyl alcohol, PEGMA-b-PCL block co-polymers, or chondroitin sulfate, have yielded scaffolds with favorable cell morphology, cytocompatibility, and in vivo repair of cartilage defects [103].

Trucco et al. engineered GO-doped gellan gum–poly(ethylene glycol) diacrylate (PEGDA) bilayer hydrogels to emulate the mechanical and lubricative functions of articular cartilage [94]. GO-containing hydrogels display excellent compressive and shear properties and lubrication comparable to native cartilage, are non-cytotoxic in vitro, and support cell proliferation and chondrocytic differentiation, which highlights the promise for joint restoration. Ogene et al. reported that GO increases plasma membrane tension and activates the TGF-β pathway in a human chondrocyte line, enhancing SMAD2/3 phosphorylation and downstream gene expression [104]. Fluorescence lifetime imaging suggested strong GO–membrane interactions that trigger mechanoresponsive signaling and endogenous TGF-β activation.

Liu et al. evaluated umbilical cord MSCs (UCMSCs) delivered with a GO-particle lubricant in a rabbit papain-induced osteoarthritis model [49]. The combination reduced inflammatory cytokines in synovial fluid and serum, ameliorated subchondral osteopenia, and promoted cartilage repair, indicating that GO particles can provide superior lubrication while acting as a stem-cell carrier to enhance therapeutic efficacy. Similarly, Wang et al. showed that UCMSCs plus a GO-particle lubricant markedly decreased nitric oxide (NO), interleukin (IL)-6, and tumor necrosis factor (TNF)-α in a modified Hulth model, while increasing glycosaminoglycan (GAG) and type II collagen (COL-II), thereby improving the joint biochemical milieu and facilitating cartilage repair [48]. GO particles alone had a limited effect and UCMSCs alone provided partial benefit.

Additive manufacturing has also been leveraged. Cheng et al. used 3D printing to fabricate GO-containing scaffolds that enhanced chondrocyte proliferation and collagen synthesis with favorable biocompatibility and mechanics in vitro and in vivo, although optimization of GO content and mechanistic dissection remain needed [96]. Li et al. developed a GO-based meniscal scaffold coated with tannic acid, Sr²⁺, and silk fibroin, which demonstrated anti-inflammatory and antioxidant (anti-ROS) effects that protect cartilage and delay osteoarthritis progression in vivo with good safety [105]. Jiao et al. employed gelatin-reduced GO nanosheets (rGO@Ge) to deliver kartogenin (KGN), promoting chondrogenic differentiation of rat adipose-derived stem cells with concomitant modulation of autophagy [106]. Abedin Dargoush et al. proposed a functional bilayer osteochondral construct (PEGDA top layer and GelMA bottom layer) incorporating nano-hydroxyapatite (nHA) and GO [107]. The scaffold improved cell adhesion, proliferation, and lineage-specific differentiation in vitro and in vivo, while providing suitable biocompatibility and mechanics for coordinated cartilage and bone regeneration.

Collectively, these studies indicated that GO can achieve the following: (i) reinforce scaffold mechanics and lubrication; (ii) present and/or potentiate chondrogenic cues (e.g., via TGF-β adsorption and mechanoactivation); (iii) serve as a carrier/lubricant to synergize with stem-cell therapies; and (iv) integrate with advanced fabrication to engineer ECM-mimetic architectures. Remaining priorities include defining optimal GO loading/functionalization, long-term in vivo safety, and standardized endpoints for translating GO-based cartilage therapies.

Applications of GO in skeletal muscle regeneration

Skeletal muscle is a contractile tissue composed of highly aligned bundles of myofibers and has a central role in locomotion and postural support [108, 109]. Severe functional impairment can arise from trauma, myopathies, or tumor ablation [19, 110–113]. To repair such injuries, investigators are actively exploring stem cell–nanomaterial strategies in which scaffolds guide cell fate and enhance differentiation capacity, thereby promoting skeletal muscle regeneration [73, 114, 115]. Owing to the favorable physical properties (moderate electrical conductivity [~0.6 S/m], ultralow density, flexibility, and high mechanical strength) graphene-derived materials are considered promising myogenic substrates. Specifically, GO-based constructs have repeatedly been shown to support myogenic precursor adhesion, proliferation, and differentiation (Table 3) [116, 117].

Shin et al. demonstrated that mixed matrices of GO with PLGA and collagen significantly enhanced proliferation and adhesion of C2C12 myoblasts and further promoted myogenic differentiation, evidenced by multinucleated myotube formation and increased myosin heavy chain (MHC) expression [118]. Consistently, Ku and Park reported that GO- and rGO-modified glass substrates modulate C2C12 differentiation [119]. GO immobilized on amine-functionalized glass with rGO produced by hydrazine reduction markedly improved cell adhesion, proliferation, and myogenesis, which was attributed to serum-protein adsorption and nanoscale topography. GO increased multinucleated myotube formation, upregulated myogenic regulators (e.g., MyoD), and boosted myogenic protein synthesis relative to unmodified and rGO substrates. The wrinkled GO surface likely anchors proteins and cells more effectively. Moreover, the higher density of GO oxygenated groups (carboxyl, hydroxyl, and epoxide) enhances serum-protein adsorption, and in turn, myogenic differentiation, which underscores the promise of GO in muscle tissue engineering.

Jo et al. showed that GO/polyacrylamide (GO/PAAm) composite hydrogels promote C2C12 growth, adhesion, and differentiation [120]. Further reduction of the composite enhanced cell–substrate interactions, likely by improving electrical conduction and simplifying intercellular electrical communication that cues myogenesis. Direct differentiation of cord blood–derived human mesenchymal stem cells (CB-hMSCs) into human skeletal muscle cells (hSkMCs) on dielectric and semiconducting thin GO films yielded superior viability, aspect ratio, and expression of myogenic markers compared to control surfaces, highlighting the translational potential of GO for muscle regeneration [45].

Aparicio-Collado et al. developed a semi-interpenetrating nanohybrid hydrogel based on sodium alginate (SA), polycaprolactone (PCL), and rGO nanosheets to engineer conductive, bioactive 3D matrices [117]. rGO markedly increased conductivity, which is critical for excitable tissues, while the network architecture improved physical integrity and biofunction, including adhesion and myogenic differentiation. This finding suggested utility for regenerating electroactive tissues, such as skeletal muscle. Keremidarska-Markova et al. examined GO and PEG-modified GO (GO-PEG) under near-infrared (NIR) irradiation in a multi-scale safety/efficacy appraisal [121]. GO/GO-PEG altered rhythmic contractions in ex vivo frog hearts and elevated ROS in C2C12 cells (attenuated after NIR). GO/GO-PEG increased diamine oxidase activity (potentiated by NIR) in rat liver. While intact mitochondrial function was unaffected, GO reduced ATPase activity in freeze–thawed mitochondria in a concentration-dependent manner. These data illustrated the complex bioeffects of GO derivatives and informed safety assessment for biomedical use.

Printable, GO-containing bioinks are also emerging. Kang et al. reported a 3D-printable hydrogel composed of gelatin–hydroxyphenylacetic acid (GHPA) and GO, crosslinked in situ via a dual-enzyme reaction, which created a supportive microenvironment that drove C2C12 differentiation into myocytes and myotubes, emphasizing the potential of GO-derived bioinks for muscle tissue engineering and regeneration [122]. From a bioactuation perspective, Ko et al. used rGO sheets to enhance the performance of a valveless biohybrid pump driven by engineered skeletal muscle [116]. rGO anchoring delayed early downregulation of connexin-43 (a barrier to myogenesis) and RNA-seq revealed upregulation of positive myogenic regulators (e.g., troponins) with suppression of negative regulators. rGO-modified myotubes generated ~3-fold higher contractile force, yielding substantially increased flow speed and rate, advancing physiologically relevant engineered muscle and high-power bio-machines.

Zhang et al. created a gelatin/rGO conductive micro-cryogel at the injectable-matrix scale that was designed as a myogenic cell carrier [123]. The rGO-mediated conductivity promoted myoblast proliferation and differentiation and in a mouse tibialis anterior injury model the micro-cryogels effectively delivered myogenic cells, which significantly improved muscle repair and regeneration. Choi et al. reported that nanoscale GO (sGO) coatings on nanopillar arrays in micro/nanotopographic systems enhanced adhesion and spreading of myoblasts and efficiently guided myogenic differentiation into mature myotubes, providing a rapid, effective in vitro platform for generating muscle cells [73].

In brief, across 2D films, hydrogels, printable bioinks, and injectable microgels, graphene-based (especially GO-based) materials provide electroconductive, mechanically robust, and protein-interactive interfaces that (i) strengthen myogenic precursor adhesion and proliferation, (ii) potentiate lineage commitment and myotube maturation, and (iii) enable functional bioactuation. Priorities for translation include defining optimal GO/rGO loading and oxidation state, standardizing electrical/mechanical cues, and thoroughly evaluating ROS-related effects and long-term biosafety in clinically relevant models.

Applications of GO in ligament and tendon repair

Injuries to ligaments and tendons remain a major challenge in sports medicine and clinical practice. These tissues possess limited intrinsic regenerative capacity. Therefore, conventional approaches, such as suture repair or grafting, often fail to restore native mechanics and function fully [124–126]. Post-injury scarring and fibrosis can further compromise functional recovery and elevate the risk of re-injury [125, 127, 128]. Consequently, current research focuses on advanced biomaterials and tissue-engineering strategies to more effectively drive ligament and tendon regeneration (Table 4).

Sarkar et al. described a poly(acrylic acid) hydrogel physically and chemically crosslinked by 2D GO that exhibited exceptional toughness and extensibility without sacrificing modulus [129]. GO, as a multifunctional crosslinker, strengthens interchain bonding, yielding hydrogel mechanics suitable for constructing artificial tissues that experience high strains, such as ligaments and myocardium, highlighting the promise for load-bearing soft-tissue repair.

Massive rotator cuff tears (MRCTs) present a formidable clinical challenge. MRCTs are typified not only by the tendon rupture but also by severe secondary muscle degeneration, including atrophy, fatty infiltration, and fibrosis [130]. These pathologic changes in the muscle are difficult to reverse with standard surgery, which primarily offers a mechanical fix, leading to high retear rates and unsatisfactory functional outcomes [131]. To address degenerative changes associated with MRCTs, Saveh Shemshaki et al. developed an electrically conductive matrix composed of graphene nanosheets (GnPs) dispersed in poly-L-lactic acid (PLLA) [132]. MRCTs are difficult to reverse with standard surgery. The GnP matrix elevates intracellular Ca²⁺ in myocytes, promotes myotube formation, and suppresses adipogenesis in vitro and reduces fatty infiltration and fibrosis, attenuates muscle atrophy, and improves tendon morphology and tensile properties in a rat MRCT model (Figure 4).

Long-term implantation revealed favorable biocompatibility with no evident visceral toxicity, suggesting translational potential for mitigating MRCT-related degeneration, lowering retear rates, and improving surgical outcomes. Therefore, this approach represents a significant paradigm shift, moving beyond simple mechanical repair to actively modulate the muscle biological environment, thereby targeting the root cause of surgical failure in MRCT treatment.

Barzegar et al. created a multifunctional hybrid hydrogel for Achilles tendon repair by chemically grafting hyperbranched polyglycerol (HPG) onto rGO and MoS₂, then integrating the hybrid with a gelatin matrix [133]. The scaffold significantly enhanced tendon regeneration, reduced inflammation, and imparted antibacterial activity in vivo, collectively supporting utility for tendon tissue engineering.

Applications of GO in modulating post-traumatic inflammation

Sports injuries typically trigger an intense inflammatory response [134]. A central therapeutic challenge is to guide the immune microenvironment from an early pro-inflammatory state (dominated by M1 macrophages) toward a pro-reparative state (with resolving inflammation), thereby preventing chronic inflammation and tissue fibrosis.

As outlined in Chapter 2, GO-based biomaterials can act as modulators of this process, although the effects are highly dependent on physicochemical parameters and context. Leveraging the intrinsic antioxidant capacity (see Section 2.2.3), GO-containing constructs can dampen the early burst of ROS and mitigate oxidative stress–related damage. In parallel, tuning GO size, oxidation state, and surface chemistry has been shown to attenuate excessive pro-inflammatory activation and improve hemocompatibility [135]. Across studies, more consistent observations include reduced pro-inflammatory cytokine output and the establishment of a microenvironment that is more permissive to tissue repair [136].

Accordingly, the application of GO in sports medicine extends beyond passive structural roles. By tempering excessive inflammation and oxidative stress in the post-traumatic environment, GO-based systems offer a promising strategy to improve the quality and efficiency of recovery from sports injuries.

Applications of GO in tendon–bone healing

Tendon–bone healing, the re-establishment of a functional enthesis after injury, is pivotal in sports trauma and orthopedic reconstruction. However, the process is frequently hindered by slow repair, fibrotic interfaces, osteopenia, and incomplete recovery of biomechanical properties [137–139], which contribute to suboptimal function and elevated re-injury risk [140–142]. While suture and graft techniques are standard, both often fall short of regenerating a native-like enthesis, motivating the development of GO-enabled materials and strategies (Figure 5).

Su et al. investigated GO-doped PLGA nanofiber membranes in a rabbit model and reported that intraoperative application of GO–PLGA significantly enhances cell proliferation and osteogenic differentiation, strengthens tendon–bone integration, and increases biomechanical properties compared to PLGA alone [140].

In a 2022 study, Yoon et al. demonstrated that a GO–alginate sheet scaffold markedly improved healing at the rat rotator cuff tendon–bone interface (TBI) [60]. GO contributed mechanical reinforcement, supporting cell activities critical for repair, while alginate provided a cyto-compatible milieu, together preserving TBI structural integrity and fostering cell–cell interactions.

Complementing these findings, Bao et al. showed that combining GO with platelet-rich plasma (PRP) optimized the PRP gel microarchitecture and mechanics and stabilized growth-factor release, thereby improving tendon–bone healing and biomechanics in a rabbit model relative to other treatments [143].

Collectively, these studies underscored the potential of GO-based composites, all of which are crucial for durable joint function, as follows: (i) enhance the local microenvironment; (ii) reinforce mechanical coupling across the enthesis; and (iii) promote biological integration. Future work should deepen mechanistic insight (ideally via multi-omics) to clarify how GO modulates cell fate decisions and immune cues during enthesis regeneration and to define dose, oxidation state, and functionalization parameters for safe, effective clinical translation.

Conclusions and future perspectives

As a two-dimensional material with distinctive physicochemical properties, GO exhibits wide-ranging promise for biomedical applications [6, 45, 116, 144, 145]. This review summarized GO chemistry and materials attributes with emerging uses in sports medicine and outlined priorities for future investigation.

GO has diverse uses due to generally favorable biocompatibility and tunable surface chemistry. Notable progress has been made in cartilage repair, skeletal muscle regeneration, ligament/tendon repair, and tendon–bone healing [94, 123, 133, 143]. GO strengthens hydrogel matrices in cartilage engineering, thereby enhancing cell adhesion and growth and improving the local microenvironment for chondrocytes [93–96]. For example, composites of GO with biocompatible polymers, such as collagen, have supported robust chondrocyte proliferation and differentiation, an important step for hyaline cartilage regeneration. GO electrical conductivity in skeletal muscle can emulate the electrophysiologic context of muscle contraction, promoting myogenic maturation and functional integration [42, 73, 117, 121]. At the same time GO nanoscale architecture offers a supportive 3D framework that facilitates nascent myofiber formation and alignment. GO-reinforced nanofibrous scaffolds in ligament and tendon repair mimics the native extracellular matrix and improves cell attachment and migration, which are key to accelerating repair, while the enhanced mechanics help the construct withstand physiologic loads and maintain structural stability during healing [129, 133]. GO has been used to promote biochemical and mechanical coupling across the interface within tendon–bone (enthesis) repair, improving TBI quality and biomechanics [60, 140, 143]. The surface functional groups can sequester growth factors, guide lineage commitment, and support formation of a graded mineralized fibrocartilage.

Despite these advances, several issues must be resolved to accelerate translation. First, biocompatibility and long-term in vivo stability require more thorough evaluation, including the risks of chronic and/or inflammatory responses following implantation [146, 147]. Current understanding of late-phase host responses to GO are incomplete, calling for standardized long-term safety studies across doses, oxidation states, flake sizes, and routes of administration [6, 102, 58]. Second, although GO provides superior mechanics and bioactivity relative to many matrices, precisely controlling the biochemical cues to meet the divergent requirements of different tissues is challenging [47, 105, 107]. Third, there is a need to engineer next-generation GO-derived biomaterials that more faithfully recapitulate the human biomechanical environment, e.g., via advanced bioprinting strategies to build constructs with complex architectures and spatially programmed functions [148, 149]. Finally, mechanistic insight is limited. Future work should integrate multi-omics (genomics, proteomics, and single-cell and spatial profiling) to interrogate how GO shapes cellular fate decisions, immune modulation, and matrix remodeling across scales [150–152].

In addition to general biosafety, the most pressing challenge lies in the inherent heterogeneity of GO surface chemistry [153]. The co-existence of hydroxyl, epoxy, and carboxyl groups in varying ratios creates a chemically anisotropic surface where different functional domains interact distinctly with proteins, cells, and tissues [153]. This heterogeneity becomes even more problematic when GO undergoes spontaneous reduction in biological environments [154]. The presence of ascorbic acid, glutathione, or enzymatic systems can progressively alter the hydrophilicity, conductivity, and bioactivity over the therapeutic timeframe [155]. Mechanical stress and inflammatory mediators make these chemical transformations particularly unpredictable in sports medicine applications, which complicates efforts to maintain consistent therapeutic effects [156].

Current GO production methods face significant limitations in achieving the precision needed for clinical use [157]. While Hummers’ method and modifications remain the industrial standard, GO with broad distributions in lateral size and C/O ratios are invariably produced [158]. These variations from batch-to-batch directly impact biological responses. Surface modification strategies often fail to achieve uniform coverage because functional groups are irregularly distributed across the GO surface [159]. This feature results in exposed patches that can trigger unwanted inflammatory responses. Another fundamental problem is that mechanical and chemical properties cannot be tuned independently. Increasing oxidation improves dispersibility but weakens the material mechanically, while reduction enhances conductivity at the cost of colloidal stability [160].

Future breakthroughs will require rethinking how GO is synthesized and engineered at multiple scales. Electrochemical and photochemical oxidation methods offer better control over size and oxidation distributions compared to traditional chemical approaches. Real-time monitoring of C/O ratios during synthesis could enable unprecedented quality control [161]. One promising direction involves developing GO derivatives with stable oxidation states that resist biological reduction [153]. For sports medicine specifically, the field needs materials that respond predictably to mechanical loading or inflammatory signals [74]. GO composites that change conductivity or release drugs in response to physiologic stress could revolutionize adaptive therapeutics. Most importantly, we must move beyond empirical optimization to establish clear relationships between GO structural parameters and the biological effects. Only then can we design materials rationally for specific therapeutic applications.

Despite promising preclinical findings, translating these results to the clinic is a formidable challenge. Most current data rely on small animals, like rodents, which simply cannot mimic the extreme load-bearing environment and complex biomechanics of the human musculoskeletal system. In addition to biomechanics, the long-term biological fate of these nanomaterials is a major blind spot. While short-term biocompatibility is often reported, data on how these materials behave over years of residence in the body are lacking. Questions remain about whether the materials degrade completely, accumulate in vital organs, or trigger chronic, low-grade inflammation that could compromise tissue healing. Regulatory bodies are unlikely to approve such therapies without rigorous evidence ruling out delayed toxicity. Future success depends on shifting focus from short-term efficacy to long-term safety monitoring in large-animal models. In summary, GO is a multifunctional platform with substantial potential across sports medicine. Priorities for the field include the following: (i) optimizing biocompatibility and long-term safety; (ii) exerting tighter control over surface chemistry and biochemical signaling; and (iii) developing structurally sophisticated, GO-based composites tailored to the mechanical and biological demands of specific tissues. Addressing these points will help realize the clinical utility of GO and broaden the impact in tissue engineering, regenerative medicine, and disease therapy.

Data availability statement

All data are available in the main text or the supplementary materials. The materials generated are available from the lead contact upon reasonable request.

Ethics Statement

No direct interactions with human or animal subjects were involved. Therefore, ethical approval and informed consent were not required.

Author contributions

Equal contribution. Mengran Xi (MX), Renwen Wan (RW), and Wei Luo (WL) contributed equally to this work.

• Conceptualization: Zhiwen Luo (ZL), Shiyi Chen (SC), Jiajun Qiu (JQ).
• Project administration: ZL, SC.
• Supervision: ZL, SC, JQ.
• Methodology (scope definition, search strategy, inclusion/exclusion criteria): MX, RW, WL, with guidance from ZL and JQ.
• Investigation / Literature search and curation: MX, RW, WL, Yanwei He (YH), Xinting Feng (XF), Tianqi Wang (TW).
• Data curation (reference management, figure/table sourcing, citation checking): MX, RW, WL, YH.
• Writing – original draft: MX, RW, WL (primary); YH, XF, TW (section drafts and figure captions).
• Writing – review & editing (scholarly revision, clinical framing, and materials science accuracy): SC (clinical and sports-medicine perspectives), JQ (materials science and nanomaterials), ZL (overall synthesis and positioning).
• Visualization (schematics and graphical summary): WL, XF, TW, with input from JQ.
• Validation (cross-checking claims against sources, internal consistency): MX, RW, YH, supervised by ZL and JQ.
• Resources (access to facilities, databases, and institutional support): SC, JQ, ZL.
• Funding acquisition: ZL, SC, JQ.

Acknowledgements and funding

Figure 1, 2, 3 and 5 were created by BioRender. https://BioRender.com. We thank Professor Qiu for his kind guidance with GO research. Use of ChatGPT5 for language editing is acknowledged with appreciation.

Conflict of interest

Dr. Zhiwen Luo is the Executive Editor of BIOI. He was not involved in the peer-review or handling of the manuscript. The other authors have no other competing interests to disclose.

Graphical abstract

Highlights

• GO mechanically reinforces scaffolds for sports medicine applications.
• GO promotes chondrogenic, tenogenic, and myogenic differentiation.
• Tendon-bone enthesis healing is enhanced by GO-based biomaterials.

Brief statement

This review systematically summarizes the application of graphene oxide (GO) in sports medicine. The review elucidates how GO mechanically reinforces biomaterials and directs stem cell differentiation to promote the repair of cartilage, skeletal muscle, tendons, ligaments, and tendon-bone enthesis. The review also critically assesses biosafety concerns and proposes future directions involving rational chemical functionalization and multi-omics analysis to optimize GO-based scaffolds.