Reduced Graphene Oxide Incorporated GelMA Hydrogel Promotes Angiogenesis For Wound Healing Applications

Enhanced growth and differentiation of neural stem cells on alginate/collagen/reduced graphene oxide composite hydrogel incorporated with lithium chloride

Introduction

Cell transplantation with hydrogel-based carriers is one of the advanced therapeutics for challenging diseases, such as spinal cord injury. Electrically conductive hydrogel has received much attention for its effect on nerve outgrowth and differentiation. Besides, a load of neuroprotective substances, such as lithium chloride can promote the differentiation properties of the hydrogel.

Methods

In this study, alginate/collagen/reduced graphene oxide hydrogel loaded with lithium chloride (AL/CO/rGO Li+) was prepared as an injectable cell delivery system for neural tissue regeneration. After determining the lithium-ion release profile, an MTT assay was performed to check neural viability. In the next step, real-time PCR was performed to evaluate the expression of cell adhesion and neurogenic markers.

Results

Our results showed that the combination of collagen fibers and rGO with alginates increased cell viability and the gene expression of collagen-binding receptor subunits such as integrin α1, and β1. Further, rGO contributed to the controlled release of lithium-ion hydrogel in terms of its plenty of negatively charged functional groups. The continuous culture of NSCs on AL/CO/rGO Li+ hydrogel increased neurogenic genes' expressions of nestin (5.9 fold), NF200 (36.8 fold), and synaptophysin (13.2 fold), as well as protein expression of NF200 and synaptophysin after about 14 days.

Conclusion

The simultaneous ability of electrical conduction and lithium-ion release of AL/CO/rGO Li+ hydrogel could provide a favorable microenvironment for NSCs by improving their survival, maintaining cell morphology, and expressing the neural marker. It may be potentially used as a therapeutic approach for stem cell transplantation in a spinal cord injury.

Synthesis and characterisation of a novel poly(2-hydroxyethylmethacrylate)-chitosan hydrogels loaded cerium oxide nanocomposites dressing on cutaneous wound healing on nursing care of chronic wound

This study was designed to establish the composition of wound dressing based on poly(2-hydroxyethylmethacrylate)-chitosan (PHEM-CS) hydrogels-loaded cerium oxide nanoparticle (CeONPs) composites for cutaneous wound healing on nursing care of the chronic wound. The as-synthesised PHEM-CS/CeONPs hydrogels nanocomposites were characterised by using UV-visible spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermo gravimetric analysis. The influence of PHEM-CS/CeONPs hydrogels nanocomposites on the gelation time, swelling ratio, in vitro degradation, and mechanical properties was investigated. The as-prepared PHEM-CS/CeONPs hydrogels nanocomposites dressing shows high antimicrobial activity against Staphylococcus aureus and Escherichia coli. Similar trends were observed for the treatment of biofilms where PHEM-CS/CeONPs hydrogels nanocomposites displayed better efficiency. Furthermore, the biological properties of PHEM-CS/CeONPs hydrogels nanocomposites had non-toxic in cell viability and excellent cell adhesion behaviour. After 2 weeks, the wounds treated with the PHEM-CS/CeONPs hydrogels nanocomposite wound dressing achieved a significant closure to 98.5 ± 4.95% compared with the PHEM-CS hydrogels with nearly 71 ± 3.55% of wound closure. Hence, this study strongly supports the possibility of using this novel PHEM-CS/CeONPs hydrogels nanocomposites wound dressing for efficient cutaneous wound healing on chronic wound infection and nursing care.

Encapsulation of Thymol in Gelatin Methacryloyl (GelMa)-Based Nanoniosome Enables Enhanced Antibiofilm Activity and Wound Healing

Non-healing wounds impose huge cost on patients, healthcare, and society, which are further fortified by biofilm formation and antimicrobial resistance (AMR) problems. Here, Thymol, an herbal antimicrobial agent, is utilized to combat AMR. For efficient delivery of Thymol gelatin methacryloyl (GelMa), a hydrophilic polymeric hydrogel with excellent biocompatibility combined with niosome was used to encapsulate Thymol. After optimization of the niosomal Thymol (Nio-Thymol) in the company of GelMa (Nio-Thymol@GelMa) to achieve maximum entrapment efficiency, minimum size, and low polydispersity index, the Thymol release peaked at 60% and 42% from Nio-Thymol@GelMa in medium with pH values of 6.5 and 7.4 after 72 h, respectively. Furthermore, Nio-Thymol@GelMa demonstrated higher antibacterial and anti-biofilm activity than Nio-Thymol and free Thymol against both Gram-negative and Gram-positive bacteria. Interestingly, compared with other obtained formulations, Nio-Thymol@GelMa also led to greater enhancement of migration of human dermal fibroblasts in vitro, and higher upregulation of the expression of certain growth factors such as FGF-1, and matrix metalloproteinases such as MMP-2 and MMP-13. These results suggest that Nio-Thymol@GelMa can represent a potential drug preparation for Thymol to enhance the wound healing process and antibacterial efficacy.

Co-assembled nanocomplexes comprising epigallocatechin gallate and berberine for enhanced antibacterial activity against multidrug resistant Staphylococcus aureus

Berberine (BBR), a major alkaloid in Coptis chinensis, and (-)-epigallocatechin-3-gallate (EGCG), a major catechin in green tea, are two common phytochemicals with numerous health benefits, including antibacterial efficacy. However, the limited bioavailability restricts their application. Advancement in the co-assembly technology to form nanocomposite nanoparticles precisely controls the morphology, electrical charge, and functionalities of the nanomaterials. Here, we have reported a simple one-step method for preparing a novel nanocomposite BBR-EGCG nanoparticles (BBR-EGCG NPs). These BBR-EGCG NPs exhibit improved biocompatibility and greater antibacterial effects both in vitro and in vivo relative to free-BBR and first-line antibiotics (i.e., benzylpenicillin potassium and ciprofloxacin). Furthermore, we demonstrated a synergistic bactericidal effect for BBR when combined with EGCG. We also evaluated the antibacterial activity of BBR and the possible synergism with EGCG in MRSA-infected wounds. A potential mechanism for synergism between S. aureus and MRSA was also explored through ATP determination, the interaction between nanoparticles and bacteria, and, then, transcription analysis. Furthermore, our experiments on S. aureus and MRSA confirmed the biofilm-scavenging effect of BBR-EGCG NPs. More importantly, toxicity analysis revealed that the BBR-EGCG NPs had no toxic effects on the major organs of mice. Finally, we proposed a green method for the fabrication of BBR-EGCG combinations, which may provide an alternative approach to treating infections with MRSA without using antibiotics.

Graphdiyne-loaded polycaprolactone nanofiber scaffold for peripheral nerve regeneration

Graphdiyne (GDY) is a kind of nanomaterial from the graphene carbon family with excellent physical and chemical properties. Despite some applications in medical engineering, GDY has not been used as an electroactive scaffold for tissue regeneration because of its unclear in vitro and in vivo biosafety profiles. Here, a conductive GDY nanomaterial-loaded polycaprolactone (PCL) scaffold was prepared by electrospinning technique. For the first time, the biocompatibility of GDY-based scaffold was assessed at the cellular and animal levels in a peripheral nerve injury (PNI) model. The findings indicated that the conductive three-dimensional (3D) GDY/PCL nerve guide conduits (NGCs) could significantly improve the proliferation, adhesion and glial expression of Schwann cells (SCs). The conduits were implanted into a rat 10-mm sciatic nerve defect model for 3 months in vivo. The toxicity of scaffolds to the organs was negligible, while the GDY/PCL NGCs significantly promoted myelination and axonal growth by upregulating the expression levels of SC marker (S100 β protein), Myelin basic protein (MBP), and axon regeneration marker (β3-tubulin protein (Tuj1) and neurofilament protein 200 (NF200)). In addition, upregulation of vascular factor expression in GDY/PCL NGC group suggested the potential role in angiogenesis to improve nerve repair by GDY nanomaterials. Our findings provide new perspectives on biocompatibility and effectiveness of GDY nanomaterial scaffold in peripheral nerve regeneration for preclinical application.

Chitosan-collagen-fibrinogen uncrosslinked scaffolds possessing skin regeneration and vascularization potential

Clinical success of regenerative medicine for treating deep-tissue skin injuries depends on the availability of skin grafts. Though bioengineered constructs are tested clinically, lack of neovascularization provide only superficial healing. Thus constructs, which promotes wound healing and supports vascularization has gained priority in tissue engineering. In this study, chitosan-collagen-fibrinogen (CCF) scaffold was fabricated using freeze-drying method without using any chemical crosslinkers. CCF scaffolds proved cytocompatibility and faster healing in in vitro scratch assay of primary human adult dermal fibroblasts cells with progressively increasing vascular endothelial growth factor-A and reducing vascular endothelial growth factor receptor 1 expressions. Skin regeneration evaluated on in vivo full thickness wound model confirmed faster remodeling with angiogenic signatures in CCF scaffold-implanted mice. Histopathological observations corroborated with stereo-zoom and SS-optical coherence tomography images of wound sites to prove the maturation of healing-bed, after 12 days of CCF implantation. Therefore, it is concluded that CCF scaffolds are promising for skin tissue regeneration and demonstrates pro-angiogenic potential.

Antibacterial, biocompatible, hemostatic, and tissue adhesive hydrogels based on fungal-derived carboxymethyl chitosan-reduced graphene oxide-polydopamine for wound healing applications

In this study, we developed biocompatible, fungus-derived carboxymethyl chitosan (FCMCS)-reduced graphene oxide (rGO)-polydopamine (PDA)-polyacrylamide (PAM) (FC-rGO-PDA) hydrogels with excellent antibacterial, hemostatic, and tissue adhesive properties for wound healing applications. FC-rGO-PDA hydrogels were prepared by the alkali-induced polymerization of DA followed by the incorporation of GO and its reduction during the polymerization AM to form a homogeneously dispersed PAM network structure in FCMCS solution. The formation of rGO was verified using UV-Vis spectra. The physicochemical properties of hydrogels were characterized by FTIR, and SEM, water contact angle measurements, and compressive studies. SEM and contact angle measurements showed that hydrogels were hydrophilic with interconnected pores and a fibrous topology. In addition, hydrogels adhered well to porcine skin with an adhesion strength of 32.6 ± 1.3 kPa, . The hydrogels exhibited viscoelastic, good compressive (77.5 kPa), swelling, and biodegradation properties. An in vitro study using skin fibroblasts and keratinocytes cells showed the hydrogel had good biocompatibility. Testing against two model bacteria, viz. Staphylococcus aureus and E. coli revealed that the FC-rGO-PDA hydrogel has antibacterial activity. Furthermore, the hydrogel exhibited hemostasis properties. Overall, the developed FC-rGO-PDA hydrogel has antibacterial and hemostasis properties, high water holding capacity, and excellent tissue adhesive properties, which make it a promising candidate for wound healing applications.

Design, optimization and characterization of a novel antibacterial chitosan-based hydrogel dressing for promoting blood coagulation and full-thickness wound healing: A biochemical and biophysical study

The use of hydrogel dressings has become increasingly popular as a scaffold for skin tissue engineering. Herein, we have developed an innovative wound dressing using chitosan, fibrinogen, nisin, and EDTA as an effective antibacterial scaffold for wound treatment. The structural and functional characteristics of the hydrogel, including morphology, mechanical strength, drug encapsulation and release, swelling behaviors, blood coagulation, cytotoxicity, and antibacterial activity, were studied. Spectroscopic studies indicated that the attachment of chitosan to fibrinogen is associated with minimal change in its secondary structure; subsequently, at higher temperatures, it is expected to preserve fibrinogen's conformational stability. Mechanical and blood coagulation analyses indicated that the incorporation of fibrinogen into the hydrogel resulted in accelerated clotting and enhanced mechanical properties. Our cell studies showed biocompatibility and non-toxicity of the hydrogel along with the promotion of cell migration. In addition, the prepared hydrogel indicated an antibacterial behavior against both Gram-positive and Gram-negative bacteria. Interestingly, the in vivo data revealed enhanced tissue regeneration and recovery within 17 days in the studied animals. Taken together, the results obtained from in vitro and histological assessments indicate that this innovatively designed hydrogel shows good potential as a candidate for wound healing.

Tissue-Engineered Injectable Gelatin-Methacryloyl Hydrogel-Based Adjunctive Therapy for Intervertebral Disc Degeneration

Gelatin-methacryloyl (GelMA) hydrogels are photosensitive with good biocompatibility and adjustable mechanical properties. The GelMA hydrogel composite system is a prospective therapeutic material based on a tissue engineering platform for treating intervertebral disc (IVD) degeneration (IVDD). The potential application value of the GelMA hydrogel composite system in the treatment of IVDD mainly includes three aspects: first, optimization of the current clinical treatment methods, including conservative treatment and surgical treatment; second, regeneration of IVD cells to reverse or repair IVDD; and finally, IVDD instead of injury plays a biomechanical role. In this paper, we summarized and analyzed the preparation of GelMA hydrogels and their excellent biological characteristics as carriers and comprehensively demonstrated the research status and prospects of GelMA hydrogel composite systems in IVDD treatment. In addition, the challenges facing the application of GelMA hydrogel composite systems and the progress of research on new hydrogels modified by GelMA hydrogels are presented. Hopefully, this study will provide theoretical guidance for the future application of GelMA hydrogel composite systems in IVDD.

Electro-stimulated drug release by methacrylated hyaluronic acid-based conductive hydrogel with enhanced mechanical properties

Recently, the design of stimuli-responsive hydrogels for controlled drug delivery systems has been extensively investigated to meet therapeutic needs and optimize the release pattern of the drug. Being a natural polyelectrolyte, hyaluronic acid (HA) is excellent potential to generate new opportunities for electro-responsive drug carrier applications. In the current study, HA-based electroconductive hydrogel was developed as a novel smart drug carrier for anti-inflammatory drug release by the combination of in-situ and post polymerization mechanisms. HA was modified through methacrylation reaction to introduce photocrosslinkable groups into its structure and then reduced graphene oxide (rGO) was encapsulated into methacrylated HA (HA/MA) hydrogel by using the photopolymerization technique. In the post polymerization process, polyaniline (PANI) was incorporated/loaded into HA/MA-rGO polymeric network produced in previous step. The produced HA/MA-rGO-PANI hydrogel exhibited sufficient electrical conductivity providing the desirable electro-responsive ability for Ibuprofen (IBU) release. Furthermore, it has superior mechanical performance compared to pure (HA/MA) and rGO containing (HA/MA-rGO) hydrogels. IBU release from the hydrogel was successfully triggered by electrical stimulation and the cumulative drug release also enhanced by increasing of the applied voltage. These results highlighted that the novel HA/MA-rGO-PANI hydrogel could be a promising candidate for electrical-stimulated anti-inflammatory release systems in neural implant applications.

Dual-light defined in situ oral mucosal lesion therapy through a mode switchable anti-bacterial and anti-inflammatory mucoadhesive hydrogel

Oral mucosal ulcer is the most prevalent oral mucosal lesion, affecting the quality of life. Due to the moist and highly dynamic oral lining, the existing oral mucoadhesives are unable to serially address the challenges of residency, hemorrhage, bacterial infection and inflammatory reaction. Herein, a dual-light defined oral mucoadhesive (ZPTA-G/HMA) was proposed, with a methacrylate gelatin-methacrylate hyaluronic acid (GelMA-HAMA, G/HMA) double network hydrogel as a matrix, tannic acid (TA) as a high content anchor moiety provider for the moist oral mucosa, and polydopamine modified zinc oxide (ZnO@PDA, ZP) as a photocatalytic antibacterial substance. This platform had good adhesive and hemostatic properties both in vitro and in vivo. Under 520 nm green light (GL) irradiation, ZPTA-G/HMA would anchor to the wet mucosa surface by crosslinking and exert broad-spectrum antibacterial ability (even including Candida albicans) by in situ producing reactive oxygen species (ROS). Moreover, under 808 nm near-infrared (NIR) irradiation, the increased release of TA combined with the photothermal effect of ZP endowed ZPTA-G/HMA with enhanced anti-inflammatory and pro-healing performance. Collectively, ZPTA-G/HMA could be switched by light sources to achieve the dual-mode real-time adjustment of in situ anti-bacterial function and controlled anti-inflammation, combined with ideal mucosal residence, thus promising in developing personalized sequential strategies for varied oral mucosal lesions.

Design Considerations, Formulation Approaches, and Strategic Advances of Hydrogel Dressings for Chronic Wound Management

Wound healing is a complex and dynamic physiological process consisting of a series of cellular and molecular events that initiate immediately after a tissue lesion, to reconstruct the skin layer. It is indubitable that patients with chronic wounds, severely infected wounds, or any metabolic disorder of the wound microenvironment always endure severe pain and discomfort that affect their quality of life. It is essential to treat chronic wounds for conserving the physical as well as mental well-being of affected patients and for convalescing to improve their quality of life. For supporting and augmenting the healing process, the selection of pertinent wound dressing is essential. A substantial reduction in healing duration, disability, associated cost, and risk of recurrent infections can be achieved via engineering wound dressings. Hydrogels play a leading role in the path of engineering ideal wound dressings. Hydrogels, comprising water to a large extent, providing a moist environment, being comfortable to patients, and having biocompatible and biodegradable properties, have found their success as suitable wound dressings in the market. The exploitation of hydrogels is increasing perpetually after substantiation of their broader therapeutic actions owing to their resemblance to dermal tissues, their capability to stimulate partial skin regeneration, and their ability to incorporate therapeutic moieties promoting wound healing. This review entails properties of hydrogel supporting wound healing, types of hydrogels, cross-linking mechanisms, design considerations, and formulation strategies of hydrogel engineering. Various categories of hydrogel wound dressing fabricated recently are discussed based on their gel network composition, degradability, and physical and chemical cross-linking mechanisms, which provide an outlook regarding the importance of tailoring the physicochemical properties of hydrogels. The examples of marketed hydrogel wound dressings are also incorporated along with the future perspectives and challenges associated with them.

Regenerated silk fibroin and alginate composite hydrogel dressings loaded with curcumin nanoparticles for bacterial-infected wound closure

It is important to treat a bacterial-infected wound with a hydrogel dressing due to its excellent biocompatibility and extracellular matrix mimicking structure. In this work, the antibacterial curcumin nanoparticles (Cur-NPs) loaded silk fibroin and sodium alginate (SF/SA) composite hydrogels have been developed as dressings for bacterial-infected wound closure. The as-prepared composite hydrogel dressings exhibited excellent biocompatibility and antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in vitro. In addition, the composite hydrogel dressings showed good tissue adhesive strength because of their high viscosity and abundance of amino groups distributed on SF, which can form multi-aldehyde polysaccharides with the tissue surface. The porous 3D structure of the composite hydrogel dressings facilitated the absorption of exudate from the wound site and promoted the fusion of cellular nutrients and metabolites. In the full-thickness skin defect model with and without bacterial infection, the Cur-NPs loaded SF/SA composite hydrogel dressings prominently improves the closure of bacterial-infected wounds by improving cell proliferation, anti-inflammatory properties, vascular remodeling, and collagen deposition.

Tomato based gelatin methacryloyl hydrogel as an effective natural and low-cost scaffold for accelerative wound healing

Oxidative stress and infection are the main reasons for postponement of wound healing rate. They can potentially lead to serious inflammation and eventually lead to a longer and more painful recovery phase. Although wound dressings based on synthetic materials with antioxidative property have been proved to exhibit remarkable effect in controlling ROS level and improving wound healing, issues, such as high cost in raw materials, complicated procedures, usage of various toxic additives, and potential allergies, have significantly confined further clinical applications. In this study, a novel type of tissue engineering scaffold, based on tomatoes (Solanum lycopersicon) and gelatin methacryloyl (GelMA), was prepared via facile lyophilization and photo cross-link method (SL/GelMA). By taking advantages of various antioxidative components, such as carotenoids, flavonoids, phenolic acids, vitamin E, and vitamin C in tomatoes, SL/GelMA can effectively regulate ROS level, relieve the oxidative stress in wound bed, promote cell migration and angiogenesis, contribute to collagen deposition, and thus accelerate the rate of wound enclosure. Along with its high biocompatibility and low allergic potential, we believe that the food-derived wound dressing with facile preparation method, easy accessibility, and high cost-effectiveness can be translated for clinical treatments of various chronic wounds.

Gelatin methacryloyl (GelMA) loaded with concentrated hypoxic pretreated adipose-derived mesenchymal stem cells(ADSCs) conditioned medium promotes wound healing and vascular regeneration in aged skin

BACKGROUND

Aging skin is characterized by a disturbed structure and lack of blood supply, which makes it difficult to heal once injured. ADSCs secrete large amounts of cytokines, which promote wound healing and vascular regeneration through paracrine secretion, and the number of cytokines can be elevated by hypoxic pretreating. However, the components of ADSCs are difficult to retain in wounds. Gelatin methacrylate (GelMA) is a photopolymerizable hydrogel synthesized from gelatin and has recently emerged as a potentially attractive material for tissue engineering applications. GelMA loaded with concentrated hypoxic pretreated ADSCs conditioned medium could provide a new method of treating wounds in aged skin.

METHODS

Primary ADSCs were isolated from human adipose tissue and characterized by flow cytometry and differentiation test. ADSCs in passages 4-6 were pretreated in the hypoxic and normoxic environments to collect conditioned medium, the conditioned medium was then concentrated to prepare concentrated ADSCs conditioned medium(cADSC-CM)(the one collected from ADSCs under hypoxia was called hypo-CM ,and the one from normoxia was called nor-CM). The concentration of cytokines was detected. After treated with cADSC-CM, the abilities of proliferation, migration, and tube formation of human umbilical vascular endothelial cells (HUVECs) were assayed, and Akt/mTOR and MAPK signal pathway was detected using western blotting. GelMA+hypo-CM hydrogel was prepared, and a comprehensive evaluation of morphology, protein release efficiency, degradation rate, mechanical properties, and rheology properties were performed. Full-thickness skin wounds were created on the backs of 20-month-old mice. After surgery, GelMA, GelMA+F12, GelMA+hypo-CM, and GelMA+nor-CM were applied to the wound surface respectively. H&E, Masson, and immunohistochemistry staining were performed, and a laser Doppler perfusion imager was used to evaluate the blood perfusion. The student's t-test was used for analysis between two groups and a one-way analysis of variance (ANOVA) was used for analysis among multi groups.

RESULTS

Our results revealed that 1) wounds in aged skin healed more slowly than that in young skin and exhibited poorer perfusion; 2) hypoxic pretreated ADSCs secreted more cytokines including VEGF by activating HIF1α; 3) hypo-CM promoted proliferation and migration of HUVECs through VEGF/Akt/mTOR and MAPK signal pathway; 4) GelMA-hypoCM accelerated wound healing and angiogenesis in aged skin in vivo.

CONCLUSION

GelMA loaded with concentrated hypoxic pretreated adipose-derived mesenchymal stem cells conditioned medium could accelerate wound healing in aged skin by promoting angiogenesis.

Three-dimensional bioprinted BMSCs-laden highly adhesive artificial periosteum containing gelatin-dopamine and graphene oxide nanosheets promoting bone defect repair

The periosteum is a connective tissue membrane adhering to the surface of bone tissue that primarily provides nutrients and regulates osteogenesis during bone development and injury healing. However, building an artificial periosteum with good adhesion properties and satisfactory osteogenesis for bone defect repair remains a challenge, especially using three-dimensional (3D) bioprinting. In this study, dopamine was first grafted onto the molecular chain of gelatin usingN-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride andN-hydroxysuccinimide (NHS) to activate the carboxyl group and produce modified gelatin-dopamine (GelDA). Next, a methacrylated gelatin, methacrylated silk fibroin, GelDA, and graphene oxide nanosheet composite bioink loaded with bone marrow mesenchymal stem cells was prepared and used for bioprinting. The physicochemical properties, biocompatibility, and osteogenic roles of the bioink and 3D bioprinted artificial periosteum were then systematically evaluated. The results showed that the developed bioink showed good thermosensitivity and printability and could be used to build 3D bioprinted artificial periosteum with satisfactory cell viability and high adhesion. Finally, the 3D bioprinted artificial periosteum could effectively enhance osteogenesis bothin vitroandin vivo. Thus, the developed 3D bioprinted artificial periosteum can prompt new bone formation and provides a promising strategy for bone defect repair.

Wound dressing based on PVA nanofiber containing silk fibroin modified with GO/ZnO nanoparticles for superficial wound healing: In vitro and in vivo evaluations

Silk fibroin (SF), extracted from Bombyx mori, has unique physicochemical properties to achieve an efficient wound dressing. In this study, reduced graphene oxide (RGO)/ZnO NPs/silk fibroin nanocomposite was made, and an innovative nanofiber of SF/polyvinyl alcohol (PVA)/RGO/ZnO NPs was ready with the electrospinning technique and successfully characterized. The results of MIC and OD analyses were used to investigate the synthesized materials' antibacterial effects and displayed that the synthesized materials could inhibit growth against Staphylococcus aureus and Escherichia coli bacteria. However, both in vitro cytotoxicity (MTT) and scratch wound studies have shown that RGO/ZnO NPs and SF/PVA/RGO/ZnO NPs are not only non-toxic to NIH 3T3 fibroblasts, but also can cause cell viability, cell proliferation, and cell migration. Furthermore, improving the synthesized nanofiber's structural properties in the presence of RGO and ZnO NPs has been confirmed by performing tensile strength, contact angle, and biodegradation analyses. Also, in a cell attachment analysis, fibroblast cells had migrated and expanded well in the nanofibrous structures. Moreover, in vivo assay, SF/PVA/RGO/ZnO NPs nanofiber treated rats and has been shown significant healing activity and tissue regeneration compared with other treated groups. Therefore, this study suggests that SF/PVA/RGO/ZnO NPs nanofiber is a hopeful wound dressing for preventing bacteria growth and improving superficial wound repair.

Engineering a conduction-consistent cardiac patch with rGO/PLCL electrospun nanofibrous membranes and human iPSC-derived cardiomyocytes

The healthy human heart has special directional arrangement of cardiomyocytes and a unique electrical conduction system, which is critical for the maintenance of effective contractions. The precise arrangement of cardiomyocytes (CMs) along with conduction consistency between CMs is essential for enhancing the physiological accuracy of in vitro cardiac model systems. Here, we prepared aligned electrospun rGO/PLCL membranes using electrospinning technology to mimic the natural heart structure. The physical, chemical and biocompatible properties of the membranes were rigorously tested. We next assembled human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) on electrospun rGO/PLCL membranes in order to construct a myocardial muscle patch. The conduction consistency of cardiomyocytes on the patches were carefully recorded. We found that cells cultivated on the electrospun rGO/PLCL fibers presented with an ordered and arranged structure, excellent mechanical properties, oxidation resistance and effective guidance. The addition of rGO was found to be beneficial for the maturation and synchronous electrical conductivity of hiPSC-CMs within the cardiac patch. This study verified the possibility of using conduction-consistent cardiac patches to enhance drug screening and disease modeling applications. Implementation of such a system could one day lead to in vivo cardiac repair applications.

Graphene-Based Materials for Inhibition of Wound Infection and Accelerating Wound Healing

Bacterial infection of the wound could potentially cause serious complications and an enormous medical and financial cost to the rapid emergence of drug-resistant bacteria. Nanomaterials are an emerging technology, that has been researched as possible antimicrobial nanomaterials for the inhibition of wound infection and enhancement of wound healing. Graphene is 2-dimensional (2D) sheet of sp² carbon atoms in a honeycomb structure. It has superior properties, strength, conductivity, antimicrobial, and molecular carrier abilities. Graphene and its derivatives, Graphene oxide (GO) and reduced GO (rGO), have antibacterial activity and could damage bacterial morphology and lead to the leakage of intracellular substances. Besides, for wound infection management, Graphene-platforms could be functionalized by different antibacterial agents such as metal-nanoparticles, natural compounds, and antibiotics. The Graphene structure can absorb near-infrared wavelengths, allowing it to be used as antimicrobial photodynamic therapy. Therefore, Graphene-based material could be used to inhibit pathogens that cause serious skin infections and destroy their biofilm community, which is one of the biggest challenges in treating wound infection. Due to its agglomerated structure, GO hydrogel could entrap and stack the bacteria; thus, it prevents their initial attachment and biofilm formation. The sharp edges of GO could destroy the extracellular polymeric substance surrounding the biofilm and ruin the biofilm biomass structure. As well as, Chitosan and different natural and synthetic polymers such as collagen and polyvinyl alcohol (PVA) also have attracted a great deal of attention for use with GO as wound dressing material. To this end, multi-functional polymers based on Graphene and blends of synthetic and natural polymers can be considered valid non-antibiotic compounds useful against wound infection and improvement of wound healing. Finally, the global wound care market size was valued at USD 20.8 billion in 2022 and is expected to expand at a compound annual growth rate (CAGR) of 5.4% from 2022 to 2027 (USD 27.2 billion). This will encourage academic as well as pharmaceutical and medical device industries to investigate any new materials such as graphene and its derivatives for the treatment of wound healing.

Hydrogel Based on Nanoclay and Gelatin Methacrylate Polymeric Matrix as a Potential Osteogenic Application

A nanocomposite hydrogel has potentially applicability in the induction of osteogenesis. The hydrogel was synthesized using 1% gelatin methacrylate (GelMA), a biodegradable and bioactive polymer containing the structure of gelatin, denatured collagen derived from the extracellular bone matrix, and 6% laponite (Lap), a synthetic phyllosilicate of nanosized particles. Initially, 0.6 g of Lap was added to deionized water, and then a solution of GelMA/Igarcure was added under stirring and UV light for crosslinking. The spectra in the Fourier-transform infrared region showed bands that indicate the interaction between gelatin and methacrylate anhydride. X-ray diffraction patterns confirmed the presence of Lap and GelMA in the hydrogel. The thermogravimetric analysis suggested an increase in the thermal stability of the hydrogel with the presence of clay mineral. Rheological analysis showed that the hydrogel had a viscosity that allowed its injectability. The hydrogel did not show acute toxicity at any of the concentrations tested according to the Artemia salina lethality test. It showed cell viability more significant than 80% in the MTT test, which makes it suitable for in vivo osteogenic induction tests. The cell differentiation test showed the differentiation of stem cells into osteogenic cells. It indicates a material with the potential for osteogenic induction and possible application in bone tissue engineering.

A Dual-Crosslinked Hydrogel Based on Gelatin Methacryloyl and Sulfhydrylated Chitosan for Promoting Wound Healing

The skin is the largest organ of the human body. Skin injuries, especially full-thickness injuries, are a major treatment challenge in clinical practice. Therefore, wound dressing materials with therapeutic effects have great practical significance in healthcare. This study used photocrosslinkable gelatin methacryloyl (GelMA) and sulfhydrylated chitosan (CS-SH) to design a double-crosslinked hydrogel for wound dressing. When crosslinked together, the resulting hydrogels showed a highly porous inner structure, and enhanced mechanical properties and moisture retention capacity. The compression modulus of the GelMA/CS-SH hydrogel (GCH) reached up to about 40 kPa and was much higher than that of pure GelMA hydrogel, and the compression modulus was increased with the amount of CS-SH. In vitro study showed no cytotoxicity of obtained hydrogels. Interestingly, a higher concentration of CS-SH slightly promoted the proliferation of cells. Moreover, the double-crosslinked hydrogel exhibited antibacterial properties because of the presence of chitosan. In vivo study based on rats showed that full-thickness skin defects healed on the 15th day. Histological results indicate that the hydrogel accelerated the repair of hair follicles and encouraged the orderly growth of collagen fibers in the wound. Furthermore, better blood vessel formation and a higher expression of VEGFR were observed in the hydrogel group when compared with the untreated control group. Based on our findings, GCH could be a promising candidate for full-thickness wound dressing.

In situ photo-crosslinked adhesive hydrogel loaded with mesenchymal stem cell-derived extracellular vesicles promotes diabetic wound healing

The delayed healing of diabetic wounds is directly affected by the disturbance of wound microenvironment, resulting from persistent inflammation, insufficient angiogenesis, and impaired cell functions. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) showed considerable therapeutic potential in diabetic wound healing. However, the low retention rate of MSC-EVs at wound sites hampers their efficacy. For skin wounds exposed to the outer environment, using a hydrogel with tissue adhesiveness under a moist wound condition is a promising strategy for wound healing. In this study, we modified methacryloyl-modified gelatin (GelMA) hydrogel with catechol motifs of dopamine to fabricate a GelMA-dopamine hydrogel. EVs isolated from MSCs were applied in the synthesized GelMA-dopamine hydrogel to prepare a GelMA-dopamine-EV hydrogel. The results demonstrated that the newly formed GelMA-dopamine hydrogel possessed improved properties of softness, adhesiveness, and absorptive capacity, as well as high biocompatibility in the working concentration (15% w/v). In addition, MSC-EVs were verified to promote cell migration and angiogenesis in vitro. In the skin wound model of diabetic rats, the GelMA-dopamine-EV hydrogel exerted prominent wound healing efficacy estimated by collagen deposition, skin appendage regeneration, and the expression of IL-6, CD31, and TGF-β. In conclusion, this combination of MSC-EVs and the modified hydrogel not only accelerates wound closure but also promotes skin structure normalization by rescuing the homeostasis of the healing microenvironment of diabetic wounds, which provides a potential approach for the treatment of diabetic wounds.

Biomembrane-Based Nanostructure- and Microstructure-Loaded Hydrogels for Promoting Chronic Wound Healing

Wound healing is a complex and dynamic process, and metabolic disturbances in the microenvironment of chronic wounds and the severe symptoms they cause remain major challenges to be addressed. The inherent properties of hydrogels make them promising wound dressings. In addition, biomembrane-based nanostructures and microstructures (such as liposomes, exosomes, membrane-coated nanostructures, bacteria and algae) have significant advantages in the promotion of wound healing, including special biological activities, flexible drug loading and targeting. Therefore, biomembrane-based nanostructure- and microstructure-loaded hydrogels can compensate for their respective disadvantages and combine the advantages of both to significantly promote chronic wound healing. In this review, we outline the loading strategies, mechanisms of action and applications of different types of biomembrane-based nanostructure- and microstructure-loaded hydrogels in chronic wound healing.

Injectable, stretchable, toughened, bioadhesive composite hydrogel for bladder injury repair†

The bladder is exposed to constant internal and external mechanical forces due to its deformation and the dynamic environment in which it is placed, which can hamper its repair after an injury. Traditional hydrogel materials have limitations regarding their use in the bladder owing to their poor mechanical and tissue adhesion properties. In this study, a composite hydrogel composed of methacrylate gelatine, methacrylated silk fibroin, and Pluronic F127 diacrylate was developed, which combines the characteristics of natural and synthetic polymers. The mechanical properties of the novel hydrogel, such as stretchability, viscoelasticity, and toughness, were improved by virtue of a particular molecular design strategy whereby covalent and non-covalent bond interactions create a cross-linking effect. In addition, the composite hydrogel has important usability properties; it can be injected in liquid format and rapidly transformed into a gel via photo-initiated crosslinking. This was demonstrated on an isolated porcine bladder where the hydrogel closed arbitrarily-shaped tissue defects within 90 s of its application, verifying its effective bioadhesive and sealing properties. This composite hydrogel has great potential for application in bladder injury repair as a tissue-engineering scaffold.

An injectable, stretchable, toughened, bioadhesive composite hydrogel offers a new application strategy for sutureless repair and tissue regeneration of injured bladders.

Nanosized Shikonin-Fe(III) Coordination Material for Synergistic Wound Treatment: An Initial Explorative Study

Shikonin (Shik), a natural pigment, has received growing interest in various biomedical fields due to its anti-inflammatory, antitumor, antimicrobial, and antioxidant ability. However, some inherent characteristics of Shik, such as its virulence, low bioavailability, and poor solubility, have limited its biomedical applicability. Here, we reported a facile synthetic method to produce the Shik-iron (III) nanoparticles (Shik-Fe NPs), which could overcome these limitations of Shik. The synthesized Shik-Fe NPs possessed a uniform size range of 110 ± 10 nm, negative surface charges, good water dispersity, and high safety. Iron distributed uniformly inside Shik-Fe NPs, and iron constituted 20% of total mass in PEGylated Shik-Fe NPs. When interacting with activated macrophages, Shik-Fe NPs significantly reduced the level of cellular inflammatory factors, for example, iNOS, IL-1β, and TNF-α. Furthermore, the Shik-Fe NPs demonstrated synergistic anti-inflammation and anti-bacterial properties in vivo, since they could release Fe³⁺ and Shik to eradicate bacteria (Staphylococcus aureus and P. aeruginosa were used as model microbes here) during wound infections and provide full recovery for scald wounds. Collectively, the study established a dual-functional Shik-derived nanoplatform, which could be useful for the treatment of various inflammation-involved diseases.

In Vitro and In Vivo Characterization Methods for Evaluation of Modern Wound Dressings

Chronic wound management represents a major challenge in the healthcare sector owing to its delayed wound-healing process progression and huge financial burden. In this regard, wound dressings provide an appropriate platform for facilitating wound healing for several decades. However, adherent traditional wound dressings do not provide effective wound healing for highly exudating chronic wounds and need the development of newer and innovative wound dressings to facilitate accelerated wound healing. In addition, these dressings need frequent changing, resulting in more pain and discomfort. In order to overcome these issues, a wide range of affordable and innovative modern wound dressings have been developed and explored recently to accelerate and improve the wound healing process. However, a comprehensive understanding of various in vitro and in vivo characterization methods being utilized for the evaluation of different modern wound dressings is lacking. In this context, an overview of modern dressings and their complete in vitro and in vivo characterization methods for wound healing assessment is provided in this review. Herein, various emerging modern wound dressings with advantages and challenges have also been reviewed. Furthermore, different in vitro wound healing assays and in vivo wound models being utilized for the evaluation of wound healing progression and wound healing rate using wound dressings are discussed in detail. Finally, a summary of modern wound dressings with challenges and the future outlook is highlighted.

Engineering functional natural polymer-based nanocomposite hydrogels for wound healing

Skin injury occurs due to acute trauma, chronic trauma, infection, and surgical intervention, which can result in severe dysfunction and even death in humans. Therefore, clinical intervention is critical for the treatment of skin wounds. One idealized method is to use wound dressings to protect skin wounds and promote wound healing. Among these wound dressings, nanocomposite natural polymer hydrogels (NNPHs) are multifunctional wound dressings for wound healing. The combination of nanomaterials and natural polymer hydrogels avoids the shortcomings of a single component. Moreover, nanomaterials could provide improved antibacterial, anti-inflammatory, antioxidant, stimuli-responsive, electrically conductive and mechanical properties of hydrogels to accelerate wound healing. This review focuses on recent advancements in NNPHs for skin wound healing and repair. Initially, the functions and requirements of NNPHs as wound dressings were introduced. Second, the design, preparation and capacities of representative NNPHs are classified based on their nanomaterial. Third, skin wound repair applications of NNPHs have been summarized based on the types of wounds. Finally, the potential issues of NNPHs are discussed, and future research is proposed to prepare idealized multifunctional NNPHs for skin tissue regeneration.

PVA-Based Nanofibers Containing Chitosan Modified with Graphene Oxide and Carbon Quantum Dot-Doped TiO2 Enhance Wound Healing in a Rat Model

Electrospun nanofibrous constructs based on nanoparticles and biopolymers have recently been used in tissue engineering because of their similarity to the extracellular matrix in nature. In this study, electrospun chitosan-carbon quantum dot-titanium dioxide-graphene oxide (CS-CQD-TiO₂-GO) nanofibrous mats were synthesized for use as wound dressings by the electrospinning method. To increase the biodegradation rate and water resistance, the fabricated nanofibrous mats were cross-linked. SEM images showed a uniform and coherent structure of CS-CQD-TiO₂-GO nanocomposites and CS-CQD-TiO₂-GO electrospun nanofibers mats. FTIR analysis, XRD pattern, SEM mapping, and EDS spectrum demonstrate the accuracy of the synthesis as well as the elemental and chemical structure of the nanofibrous mat. The water contact angle indicated that the nanofibrous mat had a hydrophilic property, which is essential for controlling wound exudates. The tensile strength and elongation tests showed that the nanofibrous mat has suitable mechanical properties for wound dressing, including significant flexibility and strength. Interestingly, antimicrobial testing illustrated that the fabricated nanofibrous mat had antibacterial activity against Gram-negative and Gram-positive bacteria. Appropriate cell viability and cytocompatibility of treated mouse fibroblast NIH3T3 cells with the nanofibrous mat were determined using an MTT assay. The animal study results confirmed the proper potential of the nanofibrous mat in wound dressing applications.

Semi-Synthetic Click-Gelatin Hydrogels as Tunable Platforms for 3D Cancer Cell Culture

Basement membrane extracts (BME) derived from Engelbreth-Holm-Swarm (EHS) mouse sarcomas such as Matrigel^® remain the gold standard extracellular matrix (ECM) for three-dimensional (3D) cell culture in cancer research. Yet, BMEs suffer from substantial batch-to-batch variation, ill-defined composition, and lack the ability for physichochemical manipulation. Here, we developed a novel 3D cell culture system based on thiolated gelatin (Gel-SH), an inexpensive and highly controlled raw material capable of forming hydrogels with a high level of biophysical control and cell-instructive bioactivity. We demonstrate the successful thiolation of gelatin raw materials to enable rapid covalent crosslinking upon mixing with a synthetic poly(ethylene glycol) (PEG)-based crosslinker. The mechanical properties of the resulting gelatin-based hydrogels were readily tuned by varying precursor material concentrations, with Young's moduli ranging from ~2.5 to 5.8 kPa. All hydrogels of varying stiffnesses supported the viability and proliferation of MDA-MB-231 and MCF-7 breast cancer cell lines for 14 and 21 days of cell culture, respectively. Additionally, the gelatin-based hydrogels supported the growth, viability, and osteogenic differentiation of patient-derived preosteoblasts over 28 days of culture. Collectively, our data demonstrate that gelatin-based biomaterials provide an inexpensive and tunable 3D cell culture platform that may overcome the limitations of traditional BMEs.

Low-Swelling Adhesive Hydrogel with Rapid Hemostasis and Potent Anti-Inflammatory Capability for Full-Thickness Oral Mucosal Defect Repair

Full-thickness oral mucosal defects are accompanied by significant blood loss and frequent infections. Instead of conventional therapies that separate hemostasis and anti-inflammation in steps, emerging hydrogels can integrate multiple functions for the successive process after defect including hemostasis/inflammatory phase, proliferative phase, and remodeling phase. However, these functions can be easily compromised by rapid swelling and degradation of hydrogels in wet oral environment. Herein, a low-swelling adhesive hydrogel with rapid hemostasis and potent anti-inflammatory capability was developed using a dual cross-linking strategy as well as a safe and facile fabrication method. It was double cross-linked hydrogel consisting of gelatin methacrylate (GelMA), nanoclay, and tannic acid (TA) (referred to as GNT). GNT hydrogel exhibited low-swelling (one-eighth of that of GelMA), excellent stretchability (211.86%), and good adhesive properties (5 times the adhesive strength of GelMA). Physicochemical characterization illuminated the close interactions among the three components. A systematic investigation of the therapeutic effects of GNT hydrogels was performed. In vitro and in vivo experimental results demonstrated the potent hemostatic property and excellent antibacterial and anti-inflammatory effects of GNT hydrogels. The RNA sequencing analysis results for rat full-thickness oral mucosal samples showed that GNT reduced inflammation levels by down-regulating the expression of multiple inflammation-related pathways, including TNF and IL-17 pathways. It also enhanced the expression levels of tissue regeneration-related genes and thus accelerated defective mucosal repair. More importantly, the therapeutic effects of GNT were superior to those of a commercial oral tissue repair membrane when applied for full-thickness oral mucosal defect repair in rabbits. In summary, the prepared low-swelling adhesive GNT hydrogel with rapid hemostasis and potent anti-inflammatory is a promising therapy for full-thickness mucosal defect in the moist and dynamic oral environment.

A comprehensive review on the applications of carbon-based nanostructures in wound healing: from antibacterial aspects to cell growth stimulation

A wound is defined as damage to the integrity of biological tissue, including skin, mucous membranes, and organ tissues. The treatment of these injuries is an important challenge for medical researchers. Various materials have been used for wound healing and dressing applications among which carbon nanomaterials have attracted significant attention due to their remarkable properties. In the present review, the latest studies on the application of carbon nanomaterials including graphene oxide (GO), reduced graphene oxide (rGO), carbon dots (CDs), carbon quantum dots (CQDs), carbon nanotubes (CNTs), carbon nanofibers (CNFs), and nanodiamonds (NDs) in wound dressing applications are evaluated. Also, a variety of carbon-based nanocomposites with advantages such as biocompatibility, hemocompatibility, reduced wound healing time, antibacterial properties, cell-adhesion, enhanced mechanical properties, and enhanced permeability to oxygen has been reported for the treatment of various wounds.

Himatanthus bracteatus-Composed In Situ Polymerizable Hydrogel for Wound Healing

The Himatanthus genus presents anti-inflammatory, antioxidant activities, suggesting potential wound-healing properties. This study aimed to develop and analyze the wound-healing properties of a photopolymerizable gelatin-based hydrogel (GelMA) containing an ethanolic extract of Himatanthus bracteatus in a murine model. The extract was obtained under high pressure conditions, incorporated (2%) into the GelMA (GelMA-HB), and physically characterized. The anti-inflammatory activity of the extract was assessed using a carrageenan-induced pleurisy model and the GelMA-HB scarring properties in a wound-healing assay. The extract reduced IL-1β and TNF-α levels (48.5 ± 6.7 and 64.1 ± 4.9 pg/mL) compared to the vehicle (94.4 ± 2.3 pg/mL and 106.3 ± 5.7 pg/mL; p < 0.001). GelMA-HB depicted significantly lower swelling and increased resistance to mechanical compression compared to GelMA (p < 0.05). GelMA-HB accelerated wound closure over the time course of the experiment (p < 0.05) and promoted a significantly greater peak of myofibroblast differentiation (36.1 ± 6.6 cells) and microvascular density (23.1 ± 0.7 microvessels) on day 7 in comparison to GelMA (31.9 ± 5.3 cells and 20.2 ± 0.6 microvessels) and the control (25.8 ± 4.6 cells and 17.5 ± 0.5 microvessels) (p < 0.05). In conclusion, GelMA-HB improved wound healing in rodents, probably by modulating the inflammatory response and myofibroblastic and microvascular differentiation.

Nanomaterials-Incorporated Chemically Modified Gelatin Methacryloyl-Based Biomedical Composites: A Novel Approach for Bone Tissue Engineering

Gelatin methacryloyl (GelMA)-based composites are evolving three-dimensional (3D) networking hydrophilic protein composite scaffolds with high water content. These protein composites have been devoted to biomedical applications due to their unique abilities, such as flexibility, soft structure, versatility, stimuli-responsiveness, biocompatibility, biodegradability, and others. They resemble the native extracellular matrix (ECM) thanks to their remarkable cell-adhesion and matrix-metalloproteinase (MMP)-responsive amino acid motifs. These favorable properties promote cells to proliferate and inflate within GelMA-protein scaffolds. The performance of GelMA composites has been enriched using cell-amenable components, including peptides and proteins with a high affinity to harmonize cellular activities and tissue morphologies. Due to their inimitable merits, GelMA systems have been used in various fields such as drug delivery, biosensor, the food industry, biomedical, and other health sectors. The current knowledge and the role of GelMA scaffolds in bone tissue engineering are limited. The rational design and development of novel nanomaterials-incorporated GelMA-based composites with unique physicochemical and biological advantages would be used to regulate cellular functionality and bone regeneration. Substantial challenges remain. This review focuses on recent progress in mitigating those disputes. The study opens with a brief introduction to bone tissue engineering and GelMA-based composites, followed by their potential applications in bone tissue engineering. The future perspectives and current challenges of GelMA composites are demonstrated. This review would guide the researchers to design and fabricate more efficient multifunctional GelMA-based composites with improved characteristics for their practical applications in bone tissue engineering and biomedical segments.

Graphene Incorporated Electrospun Nanofiber for Electrochemical Sensing and Biomedical Applications: A Critical Review

The extraordinary material graphene arrived in the fields of engineering and science to instigate a material revolution in 2004. Graphene has promptly risen as the super star due to its outstanding properties. Graphene is an allotrope of carbon and is made up of sp²-bonded carbon atoms placed in a two-dimensional honeycomb lattice. Graphite consists of stacked layers of graphene. Due to the distinctive structural features as well as excellent physico-chemical and electrical conductivity, graphene allows remarkable improvement in the performance of electrospun nanofibers (NFs), which results in the enhancement of promising applications in NF-based sensor and biomedical technologies. Electrospinning is an easy, economical, and versatile technology depending on electrostatic repulsion between the surface charges to generate fibers from the extensive list of polymeric and ceramic materials with diameters down to a few nanometers. NFs have emerged as important and attractive platform with outstanding properties for biosensing and biomedical applications, because of their excellent functional features, that include high porosity, high surface area to volume ratio, high catalytic and charge transfer, much better electrical conductivity, controllable nanofiber mat configuration, biocompatibility, and bioresorbability. The inclusion of graphene nanomaterials (GNMs) into NFs is highly desirable. Pre-processing techniques and post-processing techniques to incorporate GNMs into electrospun polymer NFs are precisely discussed. The accomplishment and the utilization of NFs containing GNMs in the electrochemical biosensing pathway for the detection of a broad range biological analytes are discussed. Graphene oxide (GO) has great importance and potential in the biomedical field and can imitate the composition of the extracellular matrix. The oxygen-rich GO is hydrophilic in nature and easily disperses in water, and assists in cell growth, drug delivery, and antimicrobial properties of electrospun nanofiber matrices. NFs containing GO for tissue engineering, drug and gene delivery, wound healing applications, and medical equipment are discussed. NFs containing GO have importance in biomedical applications, which include engineered cardiac patches, instrument coatings, and triboelectric nanogenerators (TENGs) for motion sensing applications. This review deals with graphene-based nanomaterials (GNMs) such as GO incorporated electrospun polymeric NFs for biosensing and biomedical applications, that can bridge the gap between the laboratory facility and industry.

ECM-Mimicking Hydrogels Loaded with Bone Mesenchymal Stem Cell-Derived Exosomes for the Treatment of Cartilage Defects

It is well-established that treating articular cartilage injuries is clinically challenging since they lack blood arteries, nerves, and lymphoid tissue. Recent studies have revealed that bone marrow stem cell-derived exosomes (BMSCs-Exos) exert significant chondroprotective effects through paracrine secretions, and hydrogel-based materials can synergize the exosomes through sustained release. Therefore, this research aims to synthesize an ECM (extracellular matrix)-mimicking gelatin methacryloyl (GelMA) hydrogel modified by gelatin combined with BMSCs-derived exosomes to repair cartilage damage. We first isolated and characterized exosomes from BMSCs supernatant and then loaded the exosomes into GelMA hydrogel to investigate cartilage repair effects in in vitro and in vivo experiments. The outcomes showed that the GelMA hydrogel has good biocompatibility with a 3D (three-dimensional) porous structure, exhibiting good carrier characteristics for exosomes. Furthermore, BMSCs-Exos had a significant effect on promoting chondrocyte ECM production and chondrocyte proliferation, and the GelMA hydrogel could enhance this effect through a sustained-release effect. Similarly, in vivo experiments showed that GelMA-Exos promoted cartilage regeneration in rat joint defects and the synthesis of related cartilage matrix proteins.

Hydrogel patch with pretreated stem cells accelerates wound closure in diabetic rats

Delay in wound healing is a diabetes mellites resulting disorder causing persistent microbial infections, pain, and poor quality of life. This disorder is treated by several strategies using natural biomaterials, growth factors and stem cells molded into various scaffolds which possess the potential to accelerate the closure of impaired diabetic wounds. In this study, we developed a hydrogel patch using chitosan (CS) and polyethylene glycol (PEG) with laden bone marrow-derived mesenchymal stem cells (BMSCs) that were pretreated with fibroblast growth factor 21 (FGF21). The developed hydrogel patches were characterized by scanning electron microscopy and fourier transform infrared (FTIR) spectroscopy. After studying the swelling behavior, growth factor (FGF21) was used to modulate BMSC in the hyperglycemic environment. Later, FGF21 treated BMSC were embedded in CS/PEG hydrogel patch and their wound closure effect was assessed in diabetic rats. The results showed that CS/PEG hydrogel patches have good biocompatibility and possess efficient BMSC recruiting properties. The application of CS/PEG hydrogel patches accelerated wound closure in diabetic rats as compared to the control groups. However, the use of FGF21 pretreated BMSCs laded CS/PEG hydrogel patches further increased the therapeutic efficacy of wound closure in diabetic rats. This study demonstrated that the application of a hydrogel patch of CS/PEG with FGF21 pretreated BMSCs improves diabetic wound healing, but further studies are needed on larger animals before the use of these dressings in clinical trials.

A Graphene Oxide-Angiogenin Theranostic Nanoplatform for the Therapeutic Targeting of Angiogenic Processes: The Effect of Copper-Supplemented Medium

Graphene oxide (GO) nanosheets with different content in the defective carbon species bound to oxygen sp3 were functionalized with the angiogenin (ANG) protein, to create a novel nanomedicine for modulating angiogenic processes in cancer therapies. The GO@ANG nanocomposite was scrutinized utilizing UV-visible and fluorescence spectroscopies. GO exhibits pro- or antiangiogenic effects, mostly attributed to the disturbance of ROS concentration, depending both on the total concentration (i.e., >100 ng/mL) as well as on the number of carbon species oxidized, that is, the C/O ratio. ANG is considered one of the most effective angiogenic factors that plays a vital role in the angiogenic process, often in a synergic role with copper ions. Based on these starting hypotheses, the GO@ANG nanotoxicity was assessed with the MTT colorimetric assay, both in the absence and in the presence of copper ions, by in vitro cellular experiments on human prostatic cancer cells (PC-3 line). Laser confocal microscopy (LSM) cell imaging evidenced an enhanced internationalization of GO@ANG than bare GO nanosheets, as well as significant changes in cell cytoskeleton organization and mitochondrial staining compared to the cell treatments with free ANG.

Antibacterial and Anti-Inflammatory Properties of Peptide KN-17

Peri-implantitis, an infectious disease originating from dental biofilm that forms around dental implants, which causes the loss of both osseointegration and bone tissue. KN-17, a truncated cecropin B peptide, demonstrated efficacy against certain bacterial strains associated with peri-implantitis. This study aimed to assess the antibacterial and anti-inflammatory properties and mechanisms of KN-17. The effects of KN-17 on oral pathogenic bacteria were assessed by measuring its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Moreover, the cytotoxicity and anti-inflammatory effects of KN-17 were evaluated. KN-17 inhibited the growth of Streptococcus gordonii and Fusobacterium nucleatum during in vitro biofilm formation and possessed low toxicity to hBMSCs cells. KN-17 also caused RAW264.7 macrophages to transform from M1 to M2 by downregulating pro-inflammatory and upregulating anti-inflammatory factors. It inhibited the NF-κB signaling pathway by reducing IκBα and P65 protein phosphorylation while promoting IκBα degradation and nuclear P65 translocation. KN-17 might be an efficacious prophylaxis against peri-implant inflammation.

Nanofibrous Hydrogel Nanocomposite Based on Strontium-Doped Bioglass Nanofibers for Bone Tissue Engineering Applications

Simple Summary

Currently, bone defects, diseases, and injuries are common and global problems. These defects can be treated with several surgical methods and bone grafting, but these methods have limitations, including immune disorders, risk of infection, long-term recovery, movement problems, and high costs. A promising treatment option for bone replacement is the design and construction of scaffolds that mimic the properties of bone tissue and provide a suitable environment for cell and tissue growth. Achieving successful results in this method is dependent on the composition and structure of materials used as scaffolds. Bone is a composite consisting of a mineral fraction, mainly a combination of calcium phosphate, and an organic matrix. Here, we designed and produced a porous, non-toxic, and degradable scaffold made of alginate natural polymer and bioactive glass that contains strontium as well as the common elements of bioglasses—silica, calcium, sodium, and phosphorus. The scaffold is degraded at an optimized rate with the simultaneous proliferation and growth of cells, thus providing a suitable environment for the growth and development of new tissue and blood vessels. The outcomes of this study presented this scaffold as a functional structure to be used in treating bone defects and reconstructing damaged bone.

Abstract

The main aim of the current study is to fabricate an osteocompatible, bioactive, porous, and degradable bone tissue engineering scaffold. For this purpose, bioactive glasses (BGs) were chosen due to their similarity to bone’s natural mineral composition, and the effect of replacing Ca ions with Sr on their properties were considered. First, strontium-containing BGs (Sr-BGs) were synthesized using the electrospinning technique and assembled by the sol–gel method, then they were incorporated into the alginate (Alg) matrix. Photographs of the scanning electron microscope (SEM) showed that the BG nanofibers have a diameter of 220 ± 36 nm, which was smaller than the precursor nanofibers (275 ± 66 nm). The scaffolds possess a porous internal microstructure (230–330 nm pore size) with interconnected pores. We demonstrated that the scaffolds could be degraded in the acetate sodium buffer and phosphate-buffered saline. The osteoactivity of the scaffolds was confirmed via visual inspection of the SEM illustrations after seven days of immersing them in the SBF solution. In vitro assessments disclosed that the produced Alg-based composites including Sr-BGs (Alg/Sr-BGs) are blood-compatible and biocompatible. Accumulating evidence shows that Alg/Sr-BG (5%, 10%, and 15%) hydrogels could be a promising scaffold for bone regeneration.

Polysaccharide Electrospun Nanofibers for Wound Healing Applications

As a type of biological macromolecule, natural polysaccharides have been widely used in wound healing due to their low toxicity, good biocompatibility, degradability and reproducibility. Electrospinning is a versatile and simple technique for producing continuous nanoscale fibers from a variety of natural and synthetic polymers. The application of electrospun nanofibers as wound dressings has made great progress and they are considered one of the most effective wound dressings. This paper reviews the preparation of polysaccharide nanofibers by electrospinning and their application prospects in the field of wound healing. A variety of polysaccharide nanofibers, including chitosan, starch, alginate, and hyaluronic acid are introduced. The preparation strategy of polysaccharide electrospun nanofibers and their functions in promoting wound healing are summarized. In addition, the future prospects and challenges for the preparation of polysaccharide nanofibers by electrospinning are also discussed.

Production and application of biomaterials based on polyvinyl alcohol (PVA) as wound dressing: A mini review

The development of ideal wound dressing with excellent properties, such as exudate absorption capacity, drug release control ability, and increased wound healing, is currently a major requirement for wound healing. Polyvinyl alcohol (PVA) is a biodegradable semi-crystalline synthetic polymer that has been used in the field of biotechnology such as tissue regeneration, wound dressing, and drug delivery systems. In recent years, PVA-based wound dressing materials have received considerable attention due to their excellent properties such as biodegradability, biocompatibility, non-toxicity and low cost. PVA can be used as a wound dressing material to create the necessary moist wound environment, improve the physical properties of the dressing, and increase the wound healing rates. In addition, PVA can also be mixed with other organic and inorganic materials and can be used for drug delivery and wound healing. This review article addresses the role of biomaterials based on PVA mixed with other ingredients for wound dressing. It also focuses on its recent use in wound dressings as carriers of active substances.

Co-assembling of natural drug-food homologous molecule into composite hydrogel for accelerating diabetic wound healing

Diabetic wound healing is a major clinical challenge due to its vulnerability to bacterial infection and the prolonged inflammation in the wound. Traditional dressings for the healing of diabetic wounds are often suffered from unsatisfactory efficacy and frequent dressing changes which may cause secondary damage. Therefore, it is necessary to find a wound dressing that balances material functionality, degradation, safety, and tissue regeneration. Our recent studies demonstrated that gallic acid (GA) could spontaneously form supramolecular hydrogels at a relatively high concentration. However, a single network of GA hydrogel is prone to degradation, poor adhesion, and poor swelling, and may not be suitable for wound healing dressings. In this study, a composite hydrogel (GAK) was constructed by introducing konjac glucomannan (KGM) into the gel system of gallic acid (GA) and applied to promote diabetic wound healing. The composite hydrogel (GAK) with superior surface adhesion, stability, and swelling properties than the single-network of GA hydrogel. Moreover, in vitro experiments showed that GAK hydrogel had excellent biocompatibility and exhibited antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Additionally, the GAK hydrogel could significantly accelerate angiogenesis, collagen deposition, and re-epithelialization during wound healing in diabetic mice, reducing the expression of related inflammatory proteins interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), and cyclooxygenase-2 (COX-2), and improving the wound closure rate. The findings of this study suggest that this composite hydrogel (GAK) can be an ideal dressing material for accelerating diabetic wound healing.

A self-healing hydrogel based on crosslinked hyaluronic acid and chitosan to facilitate diabetic wound healing

Traditional wound dressings are not able to provide ideal environment for diabetic wounds surface thus hampered the regrowth of fresh tissues. In this study, we designed a novel in situ forming hydrogel and used it as wound dressing material. Carboxymethyl chitosan (CMCS) and oxidized hyaluronic acid (OHA) were selected to construct a pH-responsive and self-healing hydrogel system via Schiff base reaction. Taurine (Tau) with anti-inflammatory property was loaded in the hydrogel through the aforementioned reaction. Under the slightly acidic environment of the diabetic wound site, a responsive release of taurine molecules speeded up the transfer of the taurine into the wound. The physiochemical properties of the prepared CMCS-OHA-Tau hydrogel were characterized. The CMCS-OHA-Tau hydrogel showed good biocompatibility, enhancement of cell migration and inhibited production of inflammatory cytokines.Subsequently, the hydrogel was applied on the wounds of diabetic rats and its boosted efficacy for wound recovery was confirmed.

Human Endometrium-Derived Adventitial Cell Spheroid-Loaded Antimicrobial Microneedles for Uterine Regeneration

Asherman's syndrome (AS) occurs as a consequence of severe damage to the endometrial basalis, usually leading to menstrual abnormalities, infertility, and recurrent miscarriage in women. Currently, human endometrium-derived adventitial cells (En-ADVs) are considered ideal seed cells with high pluripotency for regenerative medicine. However, critical issues such as noninvasive repair of tissues, targeting of native stem cells, and continuous action in the injured sites are not well resolved. Herein, En-ADV spheroid-loaded hierarchical microneedles (MN/En-ADV) for in situ intrauterine repair are developed. The flexible microneedles are fabricated with gelatin methacryloyl and lactoferrin, imparting the characteristics of rapid degradation and antimicrobial activity. Benefiting from an array of microwells on microneedles, En-ADVs can rapidly form 3D cell spheroids, which display higher potential for cell proliferation, differentiation, and migration than dissociated cells. With the application of MN/En-ADV, the repaired uteri show well-defined myometrial regeneration, angiogenesis, and an increase of endometrial receptivity in a rat AS model. Notably, embryos are able to implant in the reconstructed sites and remain viable, indicating that this system promotes the restoration of both normal morphology and reproductive function in the injured uterus. It is anticipated that multifunctional MN/En-ADV can be an ideal candidate for versatile in situ tissue regeneration.