Injectable graphene oxide/hydrogel-based angiogenic gene delivery system for vasculogenesis and cardiac repair

Emergence of graphene as a novel nanomaterial for cardiovascular applications

Cardiovascular diseases (CDs) are the foremost cause of death worldwide. Several promising therapeutic methods have been developed for this approach, including pharmacological, surgical intervention, cell therapy, or biomaterial implantation since heart tissue is incapable of regenerating and healing on its own. The best treatment for heart failure to date is heart transplantation and invasive surgical intervention, despite their invasiveness, donor limitations, and the possibility of being rejected by the patient's immune system. To address these challenges, research is being conducted on less invasive and efficient methods. Consequently, graphene-based materials (GBMs) have attracted a great deal of interest in the last decade because of their exceptional mechanical, electrical, chemical, antibacterial, and biocompatibility properties. An overview of GBMs' applications in the cardiovascular system has been presented in this article. Following a brief explanation of graphene and its derivatives' properties, the potential of GBMs to improve and restore cardiovascular system function by using them as cardiac tissue engineering, stents, vascular bypass grafts,and heart valve has been discussed.

Advanced gene nanocarriers/scaffolds in nonviral-mediated delivery system for tissue regeneration and repair

Tissue regeneration technology has been rapidly developed and widely applied in tissue engineering and repair. Compared with traditional approaches like surgical treatment, the rising gene therapy is able to have a durable effect on tissue regeneration, such as impaired bone regeneration, articular cartilage repair and cancer-resected tissue repair. Gene therapy can also facilitate the production of in situ therapeutic factors, thus minimizing the diffusion or loss of gene complexes and enabling spatiotemporally controlled release of gene products for tissue regeneration. Among different gene delivery vectors and supportive gene-activated matrices, advanced gene/drug nanocarriers attract exceptional attraction due to their tunable physiochemical properties, as well as excellent adaptive performance in gene therapy for tissue regeneration, such as bone, cartilage, blood vessel, nerve and cancer-resected tissue repair. This paper reviews the recent advances on nonviral-mediated gene delivery systems with an emphasis on the important role of advanced nanocarriers in gene therapy and tissue regeneration.

Surface-modified injectable poly(ethylene-glycol) diacrylate-based cryogels for localized gene delivery

Lentiviral transduction is widely used in research, has shown promise in clinical trials involving gene therapy and has been approved for CAR-T cell immunotherapy. However, most modifications are doneex vivoand rely on systemic administration of large numbers of transduced cells for clinical applications. A novel approach utilizingin situbiomaterial-based gene delivery can reduce off-target side effects while enhancing effectiveness of the manipulation process. In this study, poly(ethylene glycol) diacrylate (PEGDA)-based scaffolds were developed to enablein situlentivirus-mediated transduction. Compared to other widely popular biomaterials, PEGDA stands out due to its robustness and cost-effectiveness. These scaffolds, prepared via cryogelation, are capable of flowing through surgical needles in bothin vitroandin vivoconditions, and promptly regain their original shape. Modification with poly(L-lysine) (PLL) enables lentivirus immobilization while interconnected macroporous structure allows cell infiltration into these matrices, thereby facilitating cell-virus interaction over a large surface area for efficient transduction. Notably, these preformed injectable scaffolds demonstrate hemocompatibility, cell viability and minimally inflammatory response as shown by ourin vitroandin vivostudies involving histology and immunophenotyping of infiltrating cells. This study marks the first instance of using preformed injectable scaffolds for delivery of lentivectors, which offers a non-invasive and localized approach for delivery of factors enablingin situlentiviral transduction suitable for both tissue engineering and immunotherapeutic applications.

Chemically Programmed Hydrogels for Spatiotemporal Modulation of the Cardiac Pathological Microenvironment

After myocardial infarction (MI), sustained ischemic events induce pathological microenvironments characterized by ischemia-hypoxia, oxidative stress, inflammatory responses, matrix remodeling, and fibrous scarring. Conventional clinical therapies lack spatially targeted and temporally responsive modulation of the infarct microenvironment, leading to limited myocardial repair. Engineered hydrogels have a chemically programmed toolbox for minimally invasive localization of the pathological microenvironment and personalized responsive modulation over different pathological periods. Chemically programmed strategies for crosslinking interactions, interfacial binding, and topological microstructures in hydrogels enable minimally invasive implantation and in situ integration tailored to the myocardium. This enhances substance exchange and signal interactions within the infarcted microenvironment. Programmed responsive polymer networks, intelligent micro/nanoplatforms, and biological therapeutic cues contribute to the formation of microenvironment-modulated hydrogels with precise targeting, spatiotemporal control, and on-demand feedback. Therefore, this review summarizes the features of the MI microenvironment and chemically programmed schemes for hydrogels to conform, integrate, and modulate the cardiac pathological microenvironment. Chemically programmed strategies for oxygen-generating, antioxidant, anti-inflammatory, provascular, and electrointegrated hydrogels to stimulate iterative and translational cardiac tissue engineering are discussed.

Targeted delivery of interleukin-12 plasmid into HepG2 cells through folic acid conjugated graphene oxide nanocarrier

Successful gene therapy relies on carriers to transfer genetic materials with high efficiency and low toxicity in a targeted manner. To enhance targeted cell binding and uptake, we developed and synthesized a new gene delivery vector based on graphene oxide (GO) modified by branched polyethyleneimine (BPEI) and folic acid (FA). The GO-PEI-FA nanocarriers exhibit lower toxicity compared to unmodified PEI, as well as having the potential to efficiently condense and protect pDNA. Interestingly, increasing the polymer content in the polyplex formulation improved plasmid transfer ability. Substituting graphene oxide for PEI at an N/P ratio of 10 in the HepG2 and THP1 cell lines improved hIL-12 expression by up to approximately eightfold compared to simple PEI, which is twice as high as GO-PEI-FA in Hek293 at the same N/P ratio. Therefore, the GO-PEI-FA described in this study may serve as a targeting nanocarrier for the delivery of the hIL-12 plasmid into cells overexpressing folic acid receptors, such as those found in hepatocellular carcinoma.

Research and application of hydrogel-encapsulated mesenchymal stem cells in the treatment of myocardial infarction

Myocardial infarction (MI) stands out as a highly lethal disease that poses a significant threat to global health. Worldwide, heart failure resulting from MI remains a leading cause of human mortality. Mesenchymal stem cell (MSC) therapy has emerged as a promising therapeutic approach, leveraging its intrinsic healing properties. Nevertheless, pervasive issues, including a low cell retention rate, suboptimal survival rate, and incomplete differentiation of MSCs, present formidable challenges for further research. The introduction and advancement of biomaterials have offered a novel avenue for the exploration of MSC therapy in MI, marking considerable progress thus far. Notably, hydrogels, among the representative biomaterials, have garnered extensive attention within the biomedical field. This review delves into recent advancements, specifically focusing on the application of hydrogels to augment MSC therapy for cardiac tissue regeneration in MI.

Advancing cardiac regeneration through 3D bioprinting: methods, applications, and future directions

Cardiovascular diseases (CVDs) represent a paramount global mortality concern, and their prevalence is on a relentless ascent. Despite the effectiveness of contemporary medical interventions in mitigating CVD-related fatality rates and complications, their efficacy remains curtailed by an array of limitations. These include the suboptimal efficiency of direct cell injection and an inherent disequilibrium between the demand and availability of heart transplantations. Consequently, the imperative to formulate innovative strategies for cardiac regeneration therapy becomes unmistakable. Within this context, 3D bioprinting technology emerges as a vanguard contender, occupying a pivotal niche in the realm of tissue engineering and regenerative medicine. This state-of-the-art methodology holds the potential to fabricate intricate heart tissues endowed with multifaceted structures and functionalities, thereby engendering substantial promise. By harnessing the prowess of 3D bioprinting, it becomes plausible to synthesize functional cardiac architectures seamlessly enmeshed with the host tissue, affording a viable avenue for the restitution of infarcted domains and, by extension, mitigating the onerous yoke of CVDs. In this review, we encapsulate the myriad applications of 3D bioprinting technology in the domain of heart tissue regeneration. Furthermore, we usher in the latest advancements in printing methodologies and bioinks, culminating in an exploration of the extant challenges and the vista of possibilities inherent to a diverse array of approaches.

Advances in injectable hydrogels for radiation-induced heart disease

Radiological heart damage (RIHD) is damage caused by unavoidable irradiation of the heart during chest radiotherapy, with a long latency period and a progressively increasing proportion of delayed cardiac damage due to conventional doses of chest radiotherapy. There is a risk of inducing diseases such as acute/chronic pericarditis, myocarditis, delayed myocardial fibrosis and damage to the cardiac conduction system in humans, which can lead to myocardial infarction or even death in severe cases. This paper details the pathogenesis of RIHD and gives potential targets for treatment at the molecular and cellular level, avoiding the drawbacks of high invasiveness and immune rejection due to drug therapy, medical device implantation and heart transplantation. Injectable hydrogel therapy has emerged as a minimally invasive tissue engineering therapy to provide necessary mechanical support to the infarcted myocardium and to act as a carrier for various bioactive factors and cells to improve the cellular microenvironment in the infarcted area and induce myocardial tissue regeneration. Therefore, this paper combines bioactive factors and cellular therapeutic mechanisms with injectable hydrogels, presents recent advances in the treatment of cardiac injury after RIHD with different injectable gels, and summarizes the therapeutic potential of various types of injectable hydrogels as a potential solution.

Three-dimensional bioprinted GelMA/GO composite hydrogel for stem cell osteogenic differentiation both in vitro and in vivo

In this study, we evaluated the use of graphene oxide (GO) mixed with methyl methacrylate gelatin (GelMA) for the construction of a microenvironmental implant to repair bone defects in orthopedic surgery. A scaffold containing a GelMA/GO composite with mesenchymal stem cells (MSCs) was constructed using three-dimensional bioprinting. The survival and osteogenic capacity of MSCs in the composite bioink were evaluated using cell viability and proliferation assays, osteogenesis-related gene expression analysis, and implantation under the skin of nude mice. The printing process had little effect on cell viability. We found that GO enhanced cell proliferation but had no significant effect on cell viability. In vitro experiments suggested that GO promoted material-cell interactions and the expression of osteogenesis-related genes. In vivo experiments showed that GO decreased the degradation time of the material and increased calcium nodule deposition. In contrast to pure GelMA, the addition of GO created a suitable microenvironment to promote the differentiation of loaded exogenous MSCs in vitro and in vivo, providing a basis for the repair of bone defects.

3D Printed Conductive Hydrogel Patch Incorporated with MSC@GO for Efficient Myocardial Infarction Repair

Myocardial infarction (MI) results in an impaired heart function. Conductive hydrogel patch-based therapy has been considered as a promising strategy for cardiac repair after MI. In our study, we fabricated a three-dimensional (3D) printed conductive hydrogel patch made of fibrinogen scaffolds and mesenchymal stem cells (MSCs) combined with graphene oxide (GO) flakes (MSC@GO), capitalizing on GO's excellent mechanical property and electrical conductivity. The MSC@GO hydrogel patch can be attached to the epicardium via adhesion to provide strong electrical integration with infarcted hearts, as well as mechanical and regeneration support for the infarcted area, thereby up-regulating the expression of connexin 43 (Cx43) and resulting in effective MI repair in vivo. In addition, MI also triggers apoptosis and damage of cardiomyocytes (CMs), hindering the normal repair of the infarcted heart. GO flakes exhibit a protective effect against the apoptosis of implanted MSCs. In the mouse model of MI, MSC@GO hydrogel patch implantation supported cardiac repair by reducing cell apoptosis, promoting gap connexin protein Cx43 expression, and then boosting cardiac function. Together, this study demonstrated that the conductive hydrogel patch has versatile conductivity and mechanical support function and could therefore be a promising candidate for heart repair.

Recent advances in mesenchymal stem cell therapy for myocardial infarction

Myocardial infarction refers to the ischemic necrosis of myocardium, characterized by a sharp reduction or interruption of blood flow in the coronary arteries due to the coronary artery occlusion, resulting in severe and prolonged ischemia in the corresponding myocardium and ultimately leading to ischemic necrosis of the myocardium. Given its high risk, it is considered as one of the most serious health threats today. In current clinical practice, multiple approaches have been explored to diminish myocardial oxygen consumption and alleviate symptoms, but notable success remains elusive. Accumulated clinical evidence has showed that the implantation of mesenchymal stem cell for treating myocardial infarction is both effective and safe. Nevertheless, there persists controversy and variability regarding the standardizing MSC transplantation protocols, optimizing dosage, and determining the most effective routes of administration. Addressing these remaining issues will pave the way of integration of MSCs as a feasible mainstream cardiac treatment.

Applications of Nanotechnology in the Field of Cardiology

Cardiovascular diseases (CVDs) are a leading cause of death globally, demanding innovative therapeutic strategies. Nanoformulations, including nanoparticles, address challenges in drug delivery, stem cell therapy, imaging, and gene delivery. Nanoparticles enhance drug solubility, bioavailability, and targeted delivery, with gas microbubbles, liposomal preparations, and paramagnetic nanoparticles showing potential in treating atherosclerosis and reducing systemic side effects. In stem cell therapy, nanoparticles improve cell culture, utilizing three-dimensional nanofiber scaffolds and enhancing cardiomyocyte growth. Gold nanoparticles and poly(lactic-co-glycolic acid) (PLGA)-derived microparticles promote stem cell survival. Stem cell imaging utilizes direct labeling with nanoparticles for magnetic resonance imaging (MRI), while optical tracking employs dye-conjugated nanoparticles. In gene delivery, polymeric nanoparticles like polyethylenimine (PEI) and dendrimers, graphene-based carriers, and chitosan nanoparticles offer alternatives to virus-mediated gene transfer. The potential of magnetic nanoparticles in gene therapy is explored, particularly in hepatocellular carcinoma. Overall, nanoparticles have transformative potential in cardiovascular disease management, with ongoing research poised to enhance clinical outcomes.

Preparation of VX765 sodium alginate nanogels and evaluation of their therapeutic effect via local injection on myocardial infarction in rats

Myocardial Infarction (MI) is major cause of heart failure, highlighting the critical need for effective therapeutic strategies to improve cardiac repair. This study investigated the cardioprotective effects of VX765-coated polyethyleneimine (PEI)/sodium alginate (AG) composite nanogels (AG/PEI-VX765 NGs) in a rat model of MI. Additionally, AG-VX765 NGs and PEI-VX765 nanospheres (NPs) were synthesized and tested to compare their efficacy. MI was caused in rats by ligating the left anterior descending branch of the coronary artery, and the rats were grouped and set as Sham, MI, MI + VX765, MI + AG-VX765NGs, MI + PEI-VX765NPs, and MI + AG/PEI-VX765NGs. Results demonstrate that AG/PEI-VX765NGs were non-toxic and exhibited a sustained release of VX765. In vivo, experiments demonstrated that all treatment groups significantly enhanced cardiac function, reduced infarct size, fibrosis, and apoptosis in rats with MI, with the MI + AG/PEI-VX765NGs group exhibiting the most favorable outcomes. Our findings indicate that AG/PEI-VX765NGs represent a promising therapeutic approach for MI treatment.

Injectable hydrogel-based combination therapy for myocardial infarction: a systematic review and Meta-analysis of preclinical trials

INTRODUCTION

This study evaluates the effectiveness of a combined regimen involving injectable hydrogels for the treatment of experimental myocardial infarction.

PATIENT CONCERNS

Myocardial infarction is an acute illness that negatively affects quality of life and increases mortality rates. Experimental models of myocardial infarction can aid in disease research by allowing for the development of therapies that effectively manage disease progression and promote tissue repair.

DIAGNOSIS

Experimental animal models of myocardial infarction were established using the ligation method on the anterior descending branch of the left coronary artery (LAD).

INTERVENTIONS

The efficacy of intracardiac injection of hydrogels, combined with cells, drugs, cytokines, extracellular vesicles, or nucleic acid therapies, was evaluated to assess the functional and morphological improvements in the post-infarction heart achieved through the combined hydrogel regimen.

OUTCOMES

A literature review was conducted using PubMed, Web of Science, Scopus, and Cochrane databases. A total of 83 papers, including studies on 1332 experimental animals (rats, mice, rabbits, sheep, and pigs), were included in the meta-analysis based on the inclusion and exclusion criteria. The overall effect size observed in the group receiving combined hydrogel therapy, compared to the group receiving hydrogel treatment alone, resulted in an ejection fraction (EF) improvement of 8.87% [95% confidence interval (CI): 7.53, 10.21] and a fractional shortening (FS) improvement of 6.31% [95% CI: 5.94, 6.67] in rat models, while in mice models, the improvements were 16.45% [95% CI: 11.29, 21.61] for EF and 5.68% [95% CI: 5.15, 6.22] for FS. The most significant improvements in EF (rats: MD = 9.63% [95% CI: 4.02, 15.23]; mice: MD = 23.93% [95% CI: 17.52, 30.84]) and FS (rats: MD = 8.55% [95% CI: 2.54, 14.56]; mice: MD = 5.68% [95% CI: 5.15, 6.22]) were observed when extracellular vesicle therapy was used. Although there have been significant results in large animal experiments, the number of studies conducted in this area is limited.

CONCLUSION

The present study demonstrates that combining hydrogel with other therapies effectively improves heart function and morphology. Further preclinical research using large animal models is necessary for additional study and validation.

Recent Advances and Developments in Injectable Conductive Polymer Gels for Bioelectronics

Soft matter bioelectronics represents an emerging and interdisciplinary research frontier aiming to harness the synergy between biology and electronics for advanced diagnostic and healthcare applications. In this context, a whole family of soft gels have been recently developed with self-healing ability and tunable biological mimetic features to act as a tissue-like space bridging the interface between the electronic device and dynamic biological fluids and body tissues. This review article provides a comprehensive overview of electroactive polymer gels, formed by noncovalent intermolecular interactions and dynamic covalent bonds, as injectable electroactive gels, covering their synthesis, characterization, and applications. First, hydrogels crafted from conducting polymers (poly(3,4-ethylene-dioxythiophene) (PEDOT), polyaniline (PANi), and polypyrrole (PPy))-based networks which are connected through physical interactions (e.g., hydrogen bonding, π-π stacking, hydrophobic interactions) or dynamic covalent bonds (e.g., imine bonds, Schiff-base, borate ester bonds) are addressed. Injectable hydrogels involving hybrid networks of polymers with conductive nanomaterials (i.e., graphene oxide, carbon nanotubes, metallic nanoparticles, etc.) are also discussed. Besides, it also delves into recent advancements in injectable ionic liquid-integrated gels (iongels) and deep eutectic solvent-integrated gels (eutectogels), which present promising avenues for future research. Finally, the current applications and future prospects of injectable electroactive polymer gels in cutting-edge bioelectronic applications ranging from tissue engineering to biosensing are outlined.

Orthogonally Crosslinked Gelatin-Norbornene Hydrogels for Biomedical Applications

The thiol-norbornene photo-click reaction has exceptionally fast crosslinking efficiency compared with chain-growth polymerization at equivalent macromer contents. The orthogonal reactivity between norbornene and thiol/tetrazine permits crosslinking of synthetic and naturally derived macromolecules with modularity, including poly(ethylene glycol) (PEG)-norbornene (PEGNB), gelatin-norbornene (GelNB), among others. For example, collagen-derived gelatin contains both cell adhesive motifs (e.g., Arg-Gly-Asp or RGD) and protease-labile sequences, making it an ideal macromer for forming cell-laden hydrogels. First reported in 2014, GelNB is increasingly used in orthogonal crosslinking of biomimetic matrices in various applications. GelNB can be crosslinked into hydrogels using multi-functional thiol linkers (e.g., dithiothreitol (DTT) or PEG-tetra-thiol (PEG4SH) via visible light or longwave ultraviolet (UV) light step-growth thiol-norbornene reaction or through an enzyme-mediated crosslinking (i.e., horseradish peroxidase, HRP). GelNB-based hydrogels can also be modularly crosslinked with tetrazine-bearing macromers via inverse electron-demand Diels-Alder (iEDDA) click reaction. This review surveys the various methods for preparing GelNB macromers, the crosslinking mechanisms of GelNB-based hydrogels, and their applications in cell and tissue engineering, including crosslinking of dynamic matrices, disease modeling, and tissue regeneration, delivery of therapeutics, as well as bioprinting and biofabrication.

Hydrogels for the Treatment of Myocardial Infarction: Design and Therapeutic Strategies

Cardiovascular diseases (CVDs) have become the leading global burden of diseases in recent years and are the primary cause of human mortality and loss of healthy life expectancy. Myocardial infarction (MI) is the top cause of CVDs-related deaths, and its incidence is increasing worldwide every year. Recently, hydrogels have garnered great interest from researchers as a promising therapeutic option for cardiac tissue repair after MI. This is due to their excellent properties, including biocompatibility, mechanical properties, injectable properties, anti-inflammatory properties, antioxidant properties, angiogenic properties, and conductive properties. This review discusses the advantages of hydrogels as a novel treatment for cardiac tissue repair after MI. The design strategies of various hydrogels in MI treatment are then summarized, and the latest research progress in the field is classified. Finally, the future perspectives of this booming field are also discussed at the end of this review.

An injectable carrier for spatiotemporal and sequential release of therapeutic substances to treat myocardial infarction

Myocardial infarction (MI) has become the primary cause of cardiovascular mortality, while the current treatment methods in clinical all have their shortcomings. Injectable biomaterials have emerged as a promising solution for cardiac tissue repair after MI. In this study, we designed a smart multifunctional carrier that could meet the treatment needs of different MI pathological processes by programmatically releasing different therapeutic substances. The carrier could respond to inflammatory microenvironment in the early stage of MI with rapid release of curcumin (Cur), and then sustained release recombinant humanized collagen type III (rhCol III) to treat MI. The rapid release of Cur reduced inflammation and apoptosis in the early stages, while the sustained release of rhCol III promoted angiogenesis and cardiac repair in the later stages. In vitro and in vivo results suggested that the multifunctional carrier could effectively improve cardiac function, promote the repair of infarcted tissue, and inhibit ventricular remodeling by reducing cell apoptosis and inflammation, and promoting angiogenesis in the different pathological processes of MI. Therefore, this programmed-release carrier provides a promising protocol for MI therapy.

Nanomaterials-combined methacrylated gelatin hydrogels (GelMA) for cardiac tissue constructs

Among non-communicable diseases, cardiovascular diseases are the most prevalent, accounting for approximately 17 million deaths per year. Despite conventional treatment, cardiac tissue engineering emerges as a potential alternative for the advancement and treatment of these patients, using biomaterials to replace or repair cardiac tissues. Among these materials, gelatin in its methacrylated form (GelMA) is a biodegradable and biocompatible polymer with adjustable biophysical properties. Furthermore, gelatin has the ability to replace and perform collagen-like functions for cell development in vitro. The interest in using GelMA hydrogels combined with nanomaterials is increasingly growing to promote the responsiveness to external stimuli and improve certain properties of these hydrogels by exploring the incorporation of nanomaterials into these hydrogels to serve as electrical signaling conductive elements. This review highlights the applications of electrically conductive nanomaterials associated with GelMA hydrogels for the development of structures for cardiac tissue engineering, by focusing on studies that report the combination of GelMA with nanomaterials, such as gold and carbon derivatives (carbon nanotubes and graphene), in addition to the possibility of applying these materials in 3D tissue engineering, developing new possibilities for cardiac studies.

Formation of hen egg white lysozyme derived amyloid-based hydrogels using different gelation agents: A potential tool for drug delivery

Amyloids are highly stable protein fibrillar aggregates that get deposited in various parts of our body and cause detrimental diseases. But in nature, the presence of functional amyloids is also noted in bacteria that help them by forming hyphae, biofilm, protein reservoirs, signalling messengers, etc. Keeping this perspective in mind, the idea behind this research was to develop functional amyloids in the form of hydrogel and analyse its potential in the biomedical sector as a drug-delivery tool. The synthesis and characterisation of three types of amyloid-based hydrogels have been reported in this work. Hen Egg-White Lysozyme (HEWL) protein was chosen as the principal ingredient as it is extensively used as a standard protein for studying amyloidogenesis and has inherent antibacterial properties. Comparative studies of different hydrogel properties exhibited variations in the hydrogels based on compositional differences in them. Finally, a drug release assay was done on the synthesized hydrogels to explore their potential as drug delivery tools.

A Comprehensive Look at In Vitro Angiogenesis Image Analysis Software

One of the complex challenges faced presently by tissue engineering (TE) is the development of vascularized constructs that accurately mimic the extracellular matrix (ECM) of native tissue in which they are inserted to promote vessel growth and, consequently, wound healing and tissue regeneration. TE technique is characterized by several stages, starting from the choice of cell culture and the more appropriate scaffold material that can adequately support and supply them with the necessary biological cues for microvessel development. The next step is to analyze the attained microvasculature, which is reliant on the available labeling and microscopy techniques to visualize the network, as well as metrics employed to characterize it. These are usually attained with the use of software, which has been cited in several works, although no clear standard procedure has been observed to promote the reproduction of the cell response analysis. The present review analyzes not only the various steps previously described in terms of the current standards for evaluation, but also surveys some of the available metrics and software used to quantify networks, along with the detection of analysis limitations and future improvements that could lead to considerable progress for angiogenesis evaluation and application in TE research.

Application of graphene oxide in tumor targeting and tumor therapy

Graphene oxide (GO), as a kind of two-dimensional sp2 carbon nanomaterials, has attracted great attention in many fields in the past decade. Due to its unique physical and chemical properties, GO is showing great promise in the field of biomedicine. For GO, all the atoms on its surface are exposed to the surface with ultra-high specific surface area, and a variety of groups on the surface, such as carboxyl, hydroxyl and epoxy groups, can effectively bind/load various biomolecules. Due to the availability of these groups, GO also possesses excellent hydrophilicity and biocompatibility for the modification of the desired biocompatible molecules or polymers on the surface of GO. The nano-network structure and hydrophobicity of GO enable it to load a large number of hydrophobic drugs containing benzene rings and it has been widely used as a multi-functional nano-carrier for chemotherapeutic drug or gene delivery. This review article will give an in-depth overview of the synthesis methods of GO, the advantages and disadvantages of GO used in nano-drug delivery system, the research progress of GO as a stimulus-responsive nano-drug carrier, and the application of these intelligent systems in cancer treatment.

Directing cellular responses in a nanocomposite 3D matrix for tissue regeneration with nanoparticle-mediated drug delivery

Hydrogels play an important role in tissue engineering due to their native extracellular matrix-like characteristics, but they are insufficient in providing the necessary stimuli to support tissue formation. Efforts to integrate bioactive cues directly into hydrogels are hindered by incompatibility with hydrophobic drugs, issues of burst/uncontrolled release, and rapid degradation of the bioactive molecules. Skeletal muscle tissue repair requires internal stimuli and communication between cells for regeneration, and nanocomposite systems offer to improve the therapeutic effects in tissue regeneration. Here, the versatility of mesoporous silica nanoparticles (MSN) was leveraged to formulate a nanoparticle-hydrogel composite and to combine the benefits of controlled delivery of bioactive cues and cellular support. The tunable surface characteristics of MSNs were exploited to optimize homogeneity and intracellular drug delivery in a 3D matrix. Nanocomposite hydrogels formulated with acetylated or succinylated MSNs achieved high homogeneity in 3D distribution, with succinylated MSNs being rapidly internalized and acetylated MSNs exhibiting slower cellular uptake. MSN-hydrogel nanocomposites simultaneously allowed efficient local intracellular delivery of a hydrophobic model drug. To further study the efficiency of directing cell response, a Notch signaling inhibitor (DAPT) was incorporated into succinylated MSNs and incorporated into the hydrogel. MSN-hydrogel nanocomposites effectively downregulated the Notch signaling target genes, and accelerated and maintained the expression of myogenic markers. The current findings demonstrate a proof-of-concept in effective surface engineering strategies for MSN-based nanocomposites, suited for hydrophobic drug delivery in tissue regeneration with guided cues.

The protective effects of uric acid against myocardial ischemia via the Nrf2 pathway

Uric acid (UA) possesses both pro- and anti-oxidative properties in ischemic heart disease, but the underlying mechanism remains unclear. We aimed to investigate UA's protective effect on myocardial ischemia by examining its effects on ECG Ischemic Alterations (EIA) and H2O2-induced oxidative stress in H9C2 myocardial cells. The incidence of EIA decreased over time and was more prevalent among women than men. A U-shaped relationship was observed between UA levels and EIA incidence, with the third quartile exhibiting a protective association. Addition of 237.9 μmol/L UA improved cellular damage and oxidative stress in H2O2-treated H9C2 cells, as determined by cell viability, LDH release, ROS levels, and total antioxidant capacity assays. UA activated the Nrf2 pathway, evidenced by increased expression of Nrf2, GCLC, and HO-1 proteins. By reversing cell cycle blockage, promoting wound healing ability, improving colony-forming capacity, and increasing angiogenesis in H2O2-treated cells, UA exhibited positive effects on cardiomyocyte growth characteristics. Additionally, use of Nrf2 inhibitor ML385 confirmed the involvement of the Nrf2 pathway by negating UA's effects on oxidatively damaged cardiomyocytes. Our findings suggest that UA induces downstream antioxidant factors to ameliorate oxidative stress by activating the Nrf2 pathway, which could be one of the targets responsible for UA's beneficial effects in myocardial ischemia.

Research progress related to thermosensitive hydrogel dressings in wound healing: a review

Wound healing is a dynamic and complex process in which the microenvironment at the wound site plays an important role. As a common material for wound healing, dressings accelerate wound healing and prevent external wound infections. Hydrogels have become a hot topic in wound-dressing research because of their high water content, good biocompatibility, and adjustable physical and chemical properties. Intelligent hydrogel dressings have attracted considerable attention because of their excellent environmental responsiveness. As smart polymer hydrogels, thermosensitive hydrogels can respond to small temperature changes in the environment, and their special properties make them superior to other hydrogels. This review mainly focuses on the research progress in thermosensitive intelligent hydrogel dressings for wound healing. Polymers suitable for hydrogel formation and the appropriate molecular design of the hydrogel network to achieve thermosensitive hydrogel properties are discussed, followed by the application of thermosensitive hydrogels as wound dressings. We also discuss the future perspectives of thermosensitive hydrogels as wound dressings and provide systematic theoretical support for wound healing.

Nanotechnology in coronary heart disease

Coronary heart disease (CHD) is one of the major causes of death and disability worldwide, especially in low- and middle-income countries and among older populations. Conventional diagnostic and therapeutic approaches have limitations such as low sensitivity, high cost and side effects. Nanotechnology offers promising alternative strategies for the diagnosis and treatment of CHD by exploiting the unique properties of nanomaterials. In this review, we use bibliometric analysis to identify research hotspots in the application of nanotechnology in CHD and provide a comprehensive overview of the current state of the art. Nanomaterials with enhanced imaging and biosensing capabilities can improve the early detection of CHD through advanced contrast agents and high-resolution imaging techniques. Moreover, nanomaterials can facilitate targeted drug delivery, tissue engineering and modulation of inflammation and oxidative stress, thus addressing multiple aspects of CHD pathophysiology. We discuss the application of nanotechnology in CHD diagnosis (imaging and sensors) and treatment (regulation of macrophages, cardiac repair, anti-oxidative stress), and provide insights into future research directions and clinical translation. This review serves as a valuable resource for researchers and clinicians seeking to harness the potential of nanotechnology in the management of CHD. STATEMENT OF SIGNIFICANCE: Coronary heart disease (CHD) is the one of leading cause of death and disability worldwide. Nanotechnology offers new strategies for diagnosing and treating CHD by exploiting the unique properties of nanomaterials. This review uses bibliometric analysis to uncover research trends in the use of nanotechnology for CHD. We discuss the potential of nanomaterials for early CHD detection through advanced imaging and biosensing, targeted drug delivery, tissue engineering, and modulation of inflammation and oxidative stress. We also offer insights into future research directions and potential clinical applications. This work aims to guide researchers and clinicians in leveraging nanotechnology to improve CHD patient outcomes and quality of life.

Progress and prospect of nanotechnology for cardiac fibrosis treatment

Cardiac fibrosis is the excessive accumulation of extracellular matrix components in the heart, leading to reduced cardiac functionality and heart failure. This review provides an overview of the therapeutic applications of nanotechnology for the treatment of cardiac fibrosis. We first delve into the fundamental pathophysiology of cardiac fibrosis, highlighting the key molecular players, including Matrix Metalloproteinases, Transforming Growth Factor-beta, and several growth factors, cytokines, and signaling molecules. Each target presents a unique opportunity to develop targeted nano-therapies. We then focus on recent advancements in nanotechnology and how nanoparticles can be engineered to deliver drugs or therapeutic genes. These advanced delivery approaches have shown significant potential to inhibit fibrosis-promoting factors, thereby mitigating the fibrotic response and potentially reversing disease progression. In addition, we discuss the challenges associated with developing and translating nanotechnology-based drug delivery systems, including ensuring biocompatibility, safety, and regulatory compliance. This review highlights how nanotechnology can bridge the gap between lab research and clinical practice for treating cardiac fibrosis.

Optimization of Gelatin Methacryloyl Hydrogel Properties through an Artificial Neural Network Model

Gelatin methacryloyl (GelMA) hydrogels are promising materials for tissue engineering applications due to their biocompatibility and tunable properties. However, the time-consuming process of preparing GelMA hydrogels with desirable properties for specific biomedical applications limits their clinical use. Visible-light-induced cross-linking is a well-known method for the preparation of GelMA hydrogels; however, a comprehensive investigation on the influence of critical parameters such as Eosin Y (EY), triethanolamine (TEA), and N-vinyl-2-pyrrolidone (NVP) concentrations on the stiffness and gelation time has yet to be performed. In this study, we systematically investigated the effect of these critical parameters on the stiffness and gelation time of GelMA hydrogels. We developed an artificial neural network (ANN) model with three input variables, EY, TEA, and NVP concentrations, and two output variables, Young's modulus and gelation time, derived from our experimental design. Through the alteration of individual chemical concentrations, [EY] between 0.005 and 0.5 mM and [TEA] and [NVP] between 10 and 1000 mM, we studied the impact of these alterations on the real-time values of stiffness and gelation time. Furthermore, we demonstrated the validity of the ANN model in predicting the properties of GelMA hydrogels. We also studied cell survival to establish nontoxic concentration ranges for each component, enabling safer use of GelMA hydrogels in relevant biomedical applications. Our results showed that the ANN model can accurately predict the properties of GelMA hydrogels, allowing for the synthesis of hydrogels with desirable stiffness for various biomedical applications. In conclusion, our study provides a comprehensive library that characterizes the stiffness and gelation time and demonstrates the potential of the ANN model to predict these properties of GelMA hydrogels depending on the critical parameters. The ANN models developed here can facilitate the optimization of GelMA hydrogels with the most efficient mechanical properties that resemble a native extracellular matrix and better address the need in the in vivo microenvironment. The approach of this study is to bring research about the synthesis of GelMA hydrogels to a new level where the synthesis of these hydrogels can be standardized with minimum cost and effort.

Nanotherapeutics for the Myocardium: A Potential Alternative for Treating Cardiac Diseases

ABSTRACT

Cardiovascular diseases (CVDs) are the foremost cause of morbidity and mortality worldwide. Current clinical interventions include invasive approaches for progressed conditions and pharmacological assistance for initial stages, which has systemic side effects. Preventive, curative, diagnostic, and theranostic (therapeutic + diagnostic) approaches till date are not very useful in combating the ongoing CVD epidemic, which demands a promising efficient alternative approach. To combat the growing CVD outbreak globally, the ideal strategy is to make the therapeutic intervention least invasive and direct to the heart to reduce the bystander effects on other organs and increase the bioavailability of the therapeutics to the myocardium. The application of nanoscience and nanoparticle-mediated approaches have gained a lot of momentum because of their efficient passive and active myocardium targeting capability owing to their improved specificity and controlled release. This review provides extensive insight into the various types of nanoparticles available for CVDs, their mechanisms of targeting (eg, direct or indirect), and the utmost need for further development of bench-to-bedside cardiac tissue-based nanomedicines. Furthermore, the review aims to summarize the different ideas and methods of nanoparticle-mediated therapeutic approaches to the myocardium till date with present clinical trials and future perspectives. This review also reflects the potential of such nanoparticle-mediated tissue-targeted therapies to contribute to the sustainable development goals of good health and well-being.

Potential of graphene-based nanomaterials for cardiac tissue engineering

Cardiovascular diseases are the primary cause of death worldwide. Despite significant advances in pharmacological treatments and surgical interventions to restore heart function after myocardial infarction, it can progress to heart failure due to the restricted inherent potential of adult cardiomyocytes to self-regenerate. Hence, the evolution of new therapeutic methods is critical. Nowadays, novel approaches in tissue engineering have assisted in restoring biological and physical specifications of the injured myocardium and, hence, cardiac function. The incorporation of a supporting matrix that could mechanically and electronically support the heart tissue and stimulate the cells to proliferate and regenerate will be advantageous. Electroconductive nanomaterials can facilitate intracellular communication and aid synchronous contraction via electroactive substrate creation, preventing the issue of arrhythmia in the heart. Among a wide range of electroconductive materials, graphene-based nanomaterials (GBNs) are promising for cardiac tissue engineering (CTE) due to their outstanding features including high mechanical strength, angiogenesis, antibacterial and antioxidant properties, low cost, and scalable fabrication. In the present review, we discuss the effect of applying GBNs on angiogenesis, proliferation, and differentiation of implanted stem cells, their antibacterial and antioxidant properties, and their role in improving the electrical and mechanical properties of the scaffolds for CTE. Also, we summarize the recent research that has applied GBNs in CTE. Finally, we present a concise discussion on the challenges and prospects.

Nanosystems in Cardiovascular Medicine: Advancements, Applications, and Future Perspectives

Cardiovascular diseases (CVDs) remain a leading cause of morbidity and mortality globally. Despite significant advancements in the development of pharmacological therapies, the challenges of targeted drug delivery to the cardiovascular system persist. Innovative drug-delivery systems have been developed to address these challenges and improve therapeutic outcomes in CVDs. This comprehensive review examines various drug delivery strategies and their efficacy in addressing CVDs. Polymeric nanoparticles, liposomes, microparticles, and dendrimers are among the drug-delivery systems investigated in preclinical and clinical studies. Specific strategies for targeted drug delivery, such as magnetic nanoparticles and porous stent surfaces, are also discussed. This review highlights the potential of innovative drug-delivery systems as effective strategies for the treatment of CVDs.

A Conductive and Adhesive Hydrogel Composed of MXene Nanoflakes as a Paintable Cardiac Patch for Infarcted Heart Repair

Myocardial infarction (MI) is a major cause of death worldwide. After the occurrence of MI, the heart frequently undergoes serious pathological remodeling, leading to excessive dilation, electrical disconnection between cardiac cells, and fatal functional damage. Hence, extensive efforts have been made to suppress pathological remodeling and promote the repair of the infarcted heart. In this study, we developed a hydrogel cardiac patch that can provide mechanical support, electrical conduction, and tissue adhesiveness to aid in the recovery of an infarcted heart function. Specifically, we developed a conductive and adhesive hydrogel (CAH) by combining the two-dimensional titanium carbide (Ti₃C₂T_x) MXene with natural biocompatible polymers [i.e., gelatin and dextran aldehyde (dex-ald)]. The CAH was formed within 250 s of mixing the precursor solution and could be painted. The hydrogel containing 3.0 mg/mL MXene, 10% gelatin, and 5% dex-ald exhibited appropriate material characteristics for cardiac patch applications, including a uniform distribution of MXene, a high electrical conductivity (18.3 mS/cm), cardiac tissue-like elasticity (30.4 kPa), strong tissue adhesion (6.8 kPa), and resistance to various mechanical deformations. The CAH was cytocompatible and induced cardiomyocyte (CM) maturation in vitro, as indicated by the upregulation of connexin 43 expression and a faster beating rate. Furthermore, CAH could be painted onto the heart tissue and remained stably adhered to the beating epicardium. In vivo animal studies revealed that CAH cardiac patch treatment significantly improved cardiac function and alleviated the pathological remodeling of an infarcted heart. Thus, we believe that our MXene-based CAH can potentially serve as a promising platform for the effective repair of various electroactive tissues including the heart, muscle, and nerve tissues.

Nanomaterial-Based Scaffolds for Tissue Engineering Applications: A Review on Graphene, Carbon Nanotubes and Nanocellulose

Nanoscale biomaterials have garnered immense interest in the scientific community in the recent decade. This review specifically focuses on the application of three nanomaterials, i.e., graphene and its derivatives (graphene oxide, reduced graphene oxide), carbon nanotubes (CNTs) and nanocellulose (cellulose nanocrystals or CNCs and cellulose nanofibers or CNFs), in regenerating different types of tissues, including skin, cartilage, nerve, muscle and bone. Their excellent inherent (and tunable) physical, chemical, mechanical, electrical, thermal and optical properties make them suitable for a wide range of biomedical applications, including but not limited to diagnostics, therapeutics, biosensing, bioimaging, drug and gene delivery, tissue engineering and regenerative medicine. A state-of-the-art literature review of composite tissue scaffolds fabricated using these nanomaterials is provided, including the unique physicochemical properties and mechanisms that induce cell adhesion, growth, and differentiation into specific tissues. In addition, in vitro and in vivo cytotoxic effects and biodegradation behavior of these nanomaterials are presented. We also discuss challenges and gaps that still exist and need to be addressed in future research before clinical translation of these promising nanomaterials can be realized in a safe, efficacious, and economical manner.

Correlative radioimaging and mass spectrometry imaging: a powerful combination to study 14C-graphene oxide in vivo biodistribution

Research on graphene based nanomaterials has flourished in the last decade due their unique properties and emerging socio-economic impact. In the context of their potential exploitation for biomedical applications, there is a growing need for the development of more efficient imaging techniques to track the fate of these materials. Herein we propose the first correlative imaging approach based on the combination of radioimaging and mass spectrometry imaging for the detection of Graphene Oxide (GO) labelled with carbon-14 in mice. In this study, ¹⁴C-graphene oxide nanoribbons were produced from the oxidative opening of ¹⁴C-carbon nanotubes, and were then intensively sonicated to provide nano-size ¹⁴C-GO flakes. After Intravenous administration in mice, ¹⁴C-GO distribution was quantified by radioimaging performed on tissue slices. On the same slices, MS-imaging provided a highly resolved distribution map of the nanomaterial based on the detection of specific radical anionic carbon clusters ranging from C2˙^- to C9˙^- with a base peak at m/z 72 (¹²C) and 74 (¹⁴C) under negative laser desorption ionization mass spectrometry (LDI-MS) conditions. This proof of concept approach synergizes the strength of each technique and could be advantageous in the pre-clinical development of future Graphene-based biomedical applications.

Bioorthogonal "Click Chemistry" Bone Cement with Bioinspired Natural Mimicking Microstructures for Bone Repair

Current bone cement systems often demand free radical or metal-related initiators and/or catalysts for the crosslinking process, which may cause serious toxicity to the human body. In addition, the resultant dense scaffolds may have a prolonged degradation time and are difficult for cells to infiltrate and form new tissue. In this study, we developed a porous "click" organic-inorganic nanohybrid (PO-click-ON) cement that crosslinks via metal-free biorthogonal click chemistry and forms porous structures mimicking the native bone tissue via particulate leaching. Strain-promoted click reaction enables fast and efficient crosslinking of polymer chains with the exclusion of any toxic initiator or catalyst. The resulting PO-click-ON implants supported exceptional in vitro stem cell adhesion and osteogenic differentiation with a large portion of stem cells infiltrated deep into the scaffolds. In vivo study using a rat cranial defect model demonstrated that the PO-click-ON system achieved outstanding cell adsorption, neovascularization, and bone formation. The porous click cement developed in this study serves as a promising platform with multifunctionality for bone and other tissue engineering applications.

Gene Therapy for Regenerative Medicine

The development of biological methods over the past decade has stimulated great interest in the possibility to regenerate human tissues. Advances in stem cell research, gene therapy, and tissue engineering have accelerated the technology in tissue and organ regeneration. However, despite significant progress in this area, there are still several technical issues that must be addressed, especially in the clinical use of gene therapy. The aims of gene therapy include utilising cells to produce a suitable protein, silencing over-producing proteins, and genetically modifying and repairing cell functions that may affect disease conditions. While most current gene therapy clinical trials are based on cell- and viral-mediated approaches, non-viral gene transfection agents are emerging as potentially safe and effective in the treatment of a wide variety of genetic and acquired diseases. Gene therapy based on viral vectors may induce pathogenicity and immunogenicity. Therefore, significant efforts are being invested in non-viral vectors to enhance their efficiency to a level comparable to the viral vector. Non-viral technologies consist of plasmid-based expression systems containing a gene encoding, a therapeutic protein, and synthetic gene delivery systems. One possible approach to enhance non-viral vector ability or to be an alternative to viral vectors would be to use tissue engineering technology for regenerative medicine therapy. This review provides a critical view of gene therapy with a major focus on the development of regenerative medicine technologies to control the in vivo location and function of administered genes.

Injectable hybrid hydrogels physically crosslinked based on carrageenan and green graphene for tissue repair

Injectable and biocompatible novel hybrid hydrogels based on physically crosslinked natural biopolymers and green graphene for potential use in tissue engineering are reported. Kappa and iota carrageenan, locust bean gum and gelatin are used as biopolymeric matrix. The effect of green graphene content on the swelling behavior, mechanical properties and biocompatibility of the hybrid hydrogels is investigated. The hybrid hydrogels present a porous network with three-dimensionally interconnected microstructures, with lower pore size than that of the hydrogel without graphene. The addition of graphene into the biopolymeric network improves the stability and the mechanical properties of the hydrogels in phosphate buffer saline solution at 37 °C without noticeable change in the injectability. The mechanical properties of the hybrid hydrogels were enhanced by varying the dosage of graphene between 0.025 and 0.075 w/v%. In this range, the hybrid hydrogels preserve their integrity during mechanical test and recover the initial shape after removing the applied stress. Meanwhile, hybrid hydrogels with graphene content of up to 0.05 w/v% exhibit good biocompatibility for 3T3-L1 fibroblasts; the cells proliferate inside the gel structure and show higher spreading after 48 h. These injectable hybrid hydrogels with graphene have promising future as materials for tissue repair.

Graphene Oxide-Carbamoylated Chitosan Hydrogels with Tunable Mechanical Properties for Biological Applications

Chitosan (CH)-based hydrogels have been extensively researched in numerous biological applications, including drug delivery, biosensing, wound healing, and tissue engineering, to name a few. Previously, modified CH hydrogels by carbamoylation, using potassium cyanate (KCNO) as the cross-linker, have shown improvement in viscoelastic properties and biocompatibility. In this study, graphene oxide (GO) nanofillers are added to carbamoylated CH to form a nanocomposite hydrogel and study the influence of CH molecular weight (M_w) and GO loading concentrations on hydrogel properties. The physical properties (swelling, degradation, and porous structure) of the hydrogels can be tuned as required for cell attachment and spreading by varying both the GO concentration and the M_w of CH. Rheological characterization showed an improvement in the mechanical properties (storage modulus, yield stress, and viscosity) of the synthesized CH-GO hydrogels with an increase in the M_w of CH and the GO concentration. Human retinal pigmented epithelial-1 (RPE-1) cells seeded onto the prepared hydrogel scaffolds showed good cell viability, adhesion, and cell spreading, confirming their cytocompatibility, with dependence on both M_w of CH and GO loading.

Optimization of methacrylated gelatin /layered double hydroxides nanocomposite cell-laden hydrogel bioinks with high printability for 3D extrusion bioprinting

Layered double hydroxides (LDHs) offer unique source of inspiration for design of bone mimetic biomaterials due to their superior mechanical properties, drug delivery capability and regulation cellular behaviors, particularly by divalent metal cations in their structure. Three-dimensional (3D) bioprinting of LDHs holds great promise as a novel strategy thanks to highly tunable physiochemical properties and shear-thinning ability of LDHs, which allow shape fidelity after deposition. Herein, we introduce a straightforward strategy for extrusion bioprinting of cell laden nanocomposite hydrogel bioink of gelatin methacryloyl (GelMA) biopolymer and LDHs nanoparticles. First, we synthesized LDHs by co-precipitation process and systematically examined the effect of LDHs addition on printing parameters such as printing pressure, extrusion rate, printing speed, and finally bioink printability in creating grid-like constructs. The developed hydrogel bioinks provided precise control over extrudability, extrusion uniformity, and structural integrity after deposition. Based on the printability and rheological analysis, the printability could be altered by controlling the concentration of LDHs, and printability was found to be ideal with the addition of 3 wt % LDHs. The addition of LDHs resulted in remarkably enhanced compressive strength from 652 kPa (G-LDH0) to 1168 kPa (G-LDH3). It was shown that the printed nanocomposite hydrogel scaffolds were able to support encapsulated osteoblast survival, spreading, and proliferation in the absence of any osteoinductive factors taking advantage of LDHs. In addition, cells encapsulated in G-LDH3 had a larger cell spreading area and higher cell aspect ratio than those encapsulated in G-LDH0. Altogether, the results demonstrated that the developed GelMA/LDHs nanocomposite hydrogel bioink revealed a high potential for extrusion bioprinting with high structural fidelity to fabricate implantable 3D hydrogel constructs for repair of bone defects.

Graphene Oxide/Gelatin Nanofibrous Scaffolds Loaded with N-Acetyl Cysteine for Promoting Wound Healing

Purpose

We aimed to develop an antioxidant dressing material with pro-angiogenic potential that could promote wound healing. Gelatin (Gel) was selected to improve the biocompatibility of the scaffolds, while graphene oxide (GO) was added to enhance their mechanical property. The loaded N-Acetyl cysteine (NAC) was performing the effect of scavenging reactive oxygen species (ROS) at the wound site.

Materials and Methods

The physicochemical and mechanical properties, NAC releases, and biocompatibility of the NAC-GO-Gel scaffolds were evaluated in vitro. The regeneration capability of the scaffolds was systemically investigated in vivo using the excisional wound-splinting model in mice.

Results

The NAC-GO-Gel scaffold had a stronger mechanical property and sustainer NAC release ability than the single Gel scaffold, which resulted in a better capacity for cell proliferation and migration. Mice wound-splinting models revealed that the NAC-GO-Gel scaffold effectively accelerated wound healing, promoted re-epithelialization, enhanced neovascularization, and reduced scar formation.

Conclusion

The NAC-GO-Gel scaffold not only promotes wound healing but also reduces scar formation, showing a great potential application for the repair of skin defects.

Progressive use of nanocomposite hydrogels materials for regeneration of damaged cartilage and their tribological mechanical properties

Osteoarthritis (OA) is a non-inflammatory deteriorating debilitating state that bring about remarkable health and economic issues globally. Break down/deterioration of the articular cartilage (AC) is one of the pathologic characteristics of osteoarthritis (OA). Nanocomposite hydrogels (NCH) materials are evolving as a potential class of scaffolds for organ regeneration and tissue engineering. In recent years, innovative hydrogels specifically loaded with nanoparticles have been developed and synthesized with the goal of changing conventional cartilage treatments. The detailed development of a tailored nanocomposite hydrogels (NCH) material utilized for tissue engineering is presented in this review study. Also, the mechanical characteristics, particularly the tribological behavior, of these produced NCH have been highlighted. Large amounts of research and data on the hydrogel substance utilized in cartilage healing are summarized in the current review study. When determining future research gaps in the area of hydrogels for cartilage regeneration, such information will provide researchers an advantage to further develop NCH.

Green Synthesis of Carbon Nanoparticles (CNPs) from Biomass for Biomedical Applications

In this review, we summarize recent work on the "green synthesis" of carbon nanoparticles (CNPs) and their application with a focus on biomedical applications. Recent developments in the green synthesis of carbon nanoparticles, from renewable precursors and their application for environmental, energy-storage and medicinal applications are discussed. CNPs, especially carbon nanotubes (CNTs), carbon quantum dots (CQDs) and graphene, have demonstrated utility as high-density energy storage media, environmental remediation materials and in biomedical applications. Conventional fabrication of CNPs can entail the use of toxic catalysts; therefore, we discuss low-toxicity manufacturing as well as sustainable and environmentally friendly methodology with a focus on utilizing readily available biomass as the precursor for generating CNPs.

Recent advances in GelMA hydrogel transplantation for musculoskeletal disorders and related disease treatment

Increasing data reveals that gelatin that has been methacrylated is involved in a variety of physiologic processes that are important for therapeutic interventions. Gelatin methacryloyl (GelMA) hydrogel is a highly attractive hydrogels-based bioink because of its good biocompatibility, low cost, and photo-cross-linking structure that is useful for cell survivability and cell monitoring. Methacrylated gelatin (GelMA) has established itself as a typical hydrogel composition with extensive biomedical applications. Recent advances in GelMA have focused on integrating them with bioactive and functional nanomaterials, with the goal of improving GelMA's physical, chemical, and biological properties. GelMA's ability to modify characteristics due to the synthesis technique also makes it a good choice for soft and hard tissues. GelMA has been established to become an independent or supplementary technology for musculoskeletal problems. Here, we systematically review mechanism-of-action, therapeutic uses, and challenges and future direction of GelMA in musculoskeletal disorders. We give an overview of GelMA nanocomposite for different applications in musculoskeletal disorders, such as osteoarthritis, intervertebral disc degeneration, bone regeneration, tendon disorders and so on.

Synthesis of Hydrogels and Their Progress in Environmental Remediation and Antimicrobial Application

As a kind of efficient adsorptive material, hydrogel has a wide application prospect within different fields, owing to its unique 3D network structures composed of polymers. In this paper, different synthetic strategies, crosslinking methods and their corresponding limitations and outstanding contributions of applications in the fields of removing environmental pollutants are reviewed to further provide a prospective view of their applications in water resources sustainability. Furthermore, the applications within the biomedical field, especially in wound dressing, are also reviewed in this paper, mainly due to their unique water retention ability, antibacterial ability, and good biocompatibility. Finally, the development direction of hydrogels in the fields of environmental remediation and biomedicine were summarized and prospected.

Nanomaterial-Based Electrically Conductive Hydrogels for Cardiac Tissue Repair

Cardiovascular disease is one of major causes of deaths, and its incidence has gradually increased worldwide. For cardiovascular diseases, several therapeutic approaches, such as drugs, cell-based therapy, and heart transplantation, are currently employed; however, their therapeutic efficacy and/or practical availability are still limited. Recently, biomaterial-based tissue engineering approaches have been recognized as promising for regenerating cardiac function in patients with cardiovascular diseases, including myocardial infarction (MI). In particular, materials mimicking the characteristics of native cardiac tissues can potentially prevent pathological progression and promote cardiac repair of the heart tissues post-MI. The mechanical (softness) and electrical (conductivity) properties of biomaterials as non-biochemical cues can improve the cardiac functions of infarcted hearts by mitigating myocardial cell death and subsequent fibrosis, which often leads to cardiac tissue stiffening and high electrical resistance. Consequently, electrically conductive hydrogels that can provide mechanical strength and augment the electrical activity of the infarcted heart tissue are considered new functional materials capable of mitigating the pathological progression to heart failure and stimulating cardiac regeneration. In this review, we highlight nanomaterial-incorporated hydrogels that can induce cardiac repair after MI. Nanomaterials, including carbon-based nanomaterials and recently discovered two-dimensional nanomaterials, offer great opportunities for developing functional conductive hydrogels owing to their excellent electrical conductivity, large surface area, and ease of modification. We describe recent results using nanomaterial-incorporated conductive hydrogels as cardiac patches and injectable hydrogels for cardiac repair. While further evaluations are required to confirm the therapeutic efficacy and toxicity of these materials, they could potentially be used for the regeneration of other electrically active tissues, such as nerves and muscles.

When 2D nanomaterials meet biomolecules: design strategies and hybrid nanostructures for bone tissue engineering

2D nanomaterials show great potential in biomedical applications due to their unique physical and chemical surface properties. This review includes typical 2D nanomaterials used in bone tissue engineering (BTE), such as graphene oxide, hexagonal boron nitride, molybdenum disulfide, black phosphorus, and MXenes. Moreover, the construction methods of BTE materials with 2D nanosheets are analyzed. Before designing a BTE material, it is essential to understand the relationship between the material structure and properties. Notably, 2D nanomaterials can be hybridized with biomaterials, such as polypeptides, proteins, and polysaccharides, to improve biocompatibility and host responses. The effects of the surface properties and size of 2D nanomaterials on cellular behavior, gene expression, antibacterial properties, and cytotoxicity in BTE applications are also discussed. This work provides new design ideas and directions for constructing 2D nanomaterial-based BTE scaffolds.

Detachable Microneedle Patches Deliver Mesenchymal Stromal Cell Factor-Loaded Nanoparticles for Cardiac Repair

Intramyocardial injection is a direct and efficient approach to deliver therapeutics to the heart. However, the injected volume must be very limited, and there is injury to the injection site and leakage issues during heart beating. Herein, we developed a detachable therapeutic microneedle (MN) patch, which is comprised of mesenchymal stromal cell-secreted factors (MSCF)-loaded poly(lactic-co-glycolic acid) nanoparticles (NP) in MN tips made of elastin-like polypeptide gel, with a resolvable non-cross-linked hyaluronic acid (HA) gel as the MN base. The tips can be firmly inserted into the infarcted myocardium after base removal, and no suture is needed. In isolated neonatal rat cardiac cells, we found that the cellular uptake of MSCF-NP in the cardiomyocytes was higher than in cardiac fibroblasts. MSCF-NP promoted the proliferation of injured cardiomyocytes. In a rat model of myocardial infarction, MN-MSCF-NP treatment reduced cardiomyocyte apoptosis, restored myocardium volume, and reduced fibrosis during the cardiac remodeling process. Our work demonstrated the therapeutic potential of MN to deliver MSCF directly into the myocardium and provides a promising treatment approach for cardiac diseases.

Current Nanomedicine for Targeted Vascular Disease Treatment: Trends and Perspectives

Nanotechnology has been developed to deliver cargos effectively to the vascular system. Nanomedicine is a novel and effective approach for targeted vascular disease treatment including atherosclerosis, coronary artery disease, strokes, peripheral arterial disease, and cancer. It has been well known for some time that vascular disease patients have a higher cancer risk than the general population. During atherogenesis, the endothelial cells are activated to increase the expression of adhesion molecules such as Intercellular Adhesion Molecule 1 (ICAM-1), Vascular cell adhesion protein 1 (VCAM-1), E-selectin, and P-selectin. This biological activation of endothelial cells gives a targetability clue for nanoparticle strategies. Nanoparticle formation has a passive targeting pathway due to the increased adhesion molecule expression on the cell surface as well as increased cell activation. In addition, the VCAM-1-targeting peptide has been widely used to target the inflamed endothelial cells. Biomimetic nanoparticles using platelet and leukocyte membrane fragment strategies have been promising techniques for targeted vascular disease treatment. Cyclodextrin, a natural oligosaccharide with a hydrophobic cavity, increase the solubility of cholesterol crystals at the atherosclerotic plaque site and has been used to deliver the hydrophobic drug statin as a therapeutic in a targeted manner. In summary, nanoparticles decorated with various targeting molecules will be an effective and promising strategy for targeted vascular disease treatment.