Tailoring the Inherent Properties of Biobased Nanoparticles for Nanomedicine.

Biobased nanoparticles are at the leading edge of the rapidly developing field of nanomedicine and biotherapeutics. Their unique size, shape, and biophysical properties make them attractive tools for biomedical research, including vaccination, targeted drug delivery, and immune therapy. These nanoparticles are engineered to present native cell receptors and proteins on their surfaces, providing a biomimicking camouflage for therapeutic cargo to evade rapid degradation, immune rejection, inflammation, and clearance. Despite showing promising clinical relevance, commercial implementation of these biobased nanoparticles is yet to be fully realized. In this perspective, we discuss advanced biobased nanoparticle designs used in medical applications, such as cell membrane nanoparticles, exosomes, and synthetic lipid-derived nanoparticles, and highlight their benefits and potential challenges. Moreover, we critically assess the future of preparing such particles using artificial intelligence and machine learning. These advanced computational tools will be able to predict the functional composition and behavior of the proteins and cell receptors present on the nanoparticle surfaces. With more advancement in designing new biobased nanoparticles, this field of research could play a key role in dictating the future rational design of drug transporters, thereby ultimately improving overall therapeutic outcomes.

Nitric oxide-releasing biomaterials for promoting wound healing in impaired diabetic wounds: State of the art and recent trends.

Impaired diabetic wounds are serious pathophysiological complications associated with persistent microbial infections including failure in the closure of wounds, and the cause of a high frequency of lower limb amputations. The healing of diabetic wounds is attenuated due to the lack of secretion of growth factors, prolonged inflammation, and/or inhibition of angiogenic activity. Diabetic wound healing can be enhanced by supplying nitric oxide (NO) endogenously or exogenously. NO produced inside the cells by endothelial nitric oxide synthase (eNOS) naturally aids wound healing through its beneficial vasculogenic effects. However, during hyperglycemia, the activity of eNOS is affected, and thus there becomes an utmost need for the topical supply of NO from exogenous sources. Thus, NO-donors that can release NO are loaded into wound healing patches or wound coverage matrices to treat diabetic wounds. The burst release of NO from its donors is prevented by encapsulating them in polymeric hydrogels or nanoparticles for supplying NO for an extended duration of time to the diabetic wounds. In this article, we review the etiology of diabetic wounds, wound healing strategies, and the role of NO in the wound healing process. We further discuss the challenges faced in translating NO-donors as a clinically viable nanomedicine strategy for the treatment of diabetic wounds with a focus on the use of biomaterials for the encapsulation and in vivo controlled delivery of NO-donors.

Development of nitric oxide releasing visible light crosslinked gelatin methacrylate hydrogel for rapid closure of diabetic wounds.

Management of non-healing and slow to heal diabetic wounds is a major concern in healthcare across the world. Numerous techniques have been investigated to solve the issue of delayed wound healing, though, mostly unable to promote complete healing of diabetic wounds due to the lack of proper cell proliferation, poor cell-cell communication, and higher chances of wound infections. These challenges can be minimized by using hydrogel based wound healing patches loaded with bioactive agents. Gelatin methacrylate (GelMA) has been proven to be a highly cell friendly, cell adhesive, and inexpensive biopolymer for various tissue engineering and wound healing applications. In this study, S-Nitroso-N-acetylpenicillamine (SNAP), a nitric oxide (NO) donor, was incorporated in a highly porous GelMA hydrogel patch to improve cell proliferation, facilitate rapid cell migration, and enhance diabetic wound healing. We adopted a visible light crosslinking method to fabricate this highly porous biodegradable but relatively stable patch. Developed patches were characterized for morphology, NO release, cell proliferation and migration, and diabetic wound healing in a rat model. The obtained results indicate that SNAP loaded visible light crosslinked GelMA hydrogel patches can be highly effective in promoting diabetic wound healing.

3D Bioprinted cancer models: Revolutionizing personalized cancer therapy.

After cardiovascular disease, cancer is the leading cause of death worldwide with devastating health and economic consequences, particularly in developing countries. Inter-patient variations in anti-cancer drug responses further limit the success of therapeutic interventions. Therefore, personalized medicines approach is key for this patient group involving molecular and genetic screening and appropriate stratification of patients to treatment regimen that they will respond to. However, the knowledge related to adequate risk stratification methods identifying patients who will respond to specific anti-cancer agents is still lacking in many cancer types. Recent advancements in three-dimensional (3D) bioprinting technology, have been extensively used to generate representative bioengineered tumor in vitro models, which recapitulate the human tumor tissues and microenvironment for high-throughput drug screening. Bioprinting process involves the precise deposition of multiple layers of different cell types in combination with biomaterials capable of generating 3D bioengineered tissues based on a computer-aided design. Bioprinted cancer models containing patient-derived cancer and stromal cells together with genetic material, extracellular matrix proteins and growth factors, represent a promising approach for personalized cancer therapy screening. Both natural and synthetic biopolymers have been utilized to support the proliferation of cells and biological material within the personalized tumor models/implants. These models can provide a physiologically pertinent cell-cell and cell-matrix interactions by mimicking the 3D heterogeneity of real tumors. Here, we reviewed the potential applications of 3D bioprinted tumor constructs as personalized in vitro models in anticancer drug screening and in the establishment of precision treatment regimens.

Gelatin-methacryloyl hydrogel based in vitro blood-brain barrier model for studying breast cancer-associated brain metastasis.

Breast cancer is one of the leading causes of brain metastasis. Metastasis to the brain occurs if cancer cells manage to traverse the 'blood-brain barrier' (BBB), which is a barrier with a very tight junction (TJ) of endothelial cells between blood circulation and brain tissue. It is highly important to develop novel in vitro BBB models to investigate breast cancer metastasis to the brain to facilitate the screening of chemotherapeutic agents against it. We herein report the development of gelatin methacryloyl (GelMA) modified transwell insert based BBB model composed of endothelial and astrocyte cell layers for testing the efficacy of anti-metastatic agents against breast cancer metastasis to the brain. We characterized the developed model for the morphology and in vitro breast cancer cell migration. Furthermore, we investigated the effect of cisplatin, a widely used chemotherapeutic agent, on the migration of metastatic breast cancer cells using the model. Our results showed that breast cancer cells migrate across the developed BBB model. Cisplatin treatment inhibited the migration of cancer cells across the model. Findings of this study suggest that our BBB model can be used as a suitable tool to investigate breast cancer-associated brain metastasis and to identify suitable therapeutic agents against this.

Cerium Oxide Nanoparticle-Loaded Gelatin Methacryloyl Hydrogel Wound-Healing Patch with Free Radical Scavenging Activity.

Nonhealing wounds in diabetic patients are a critical challenge, which often cause amputation and mortality. High levels of oxidative stress and aberrations in antioxidant defense mechanisms increase the adverse manifestations of diabetes mellitus. In this study, we developed a biodegradable gelatin methacryloyl (GelMA) hydrogel patch incorporated with cerium oxide nanoparticles (CONPs) for promoting diabetic wound healing. The patches were thoroughly characterized for the morphology, physicomechanical properties, free radical scavenging activity, in vitro cell proliferation, and in vivo diabetic wound healing activity. Highly porous and biodegradable patches showed excellent exudate uptake capacity as evident from the many-fold weight gain (400-700 times) when placed in aqueous medium. Results of free radical scavenging assays clearly indicated that the patches loaded with 1-4% w/w CONPs could effectively inactivate experimentally generated free radicals. Obtained results of in vitro cell culture studies clearly indicated that CONP-incorporated patches could favor the proliferation of skin-associated cells such as keratinocytes and fibroblasts. Results of the wound healing study showed that 1% w/w CONP-loaded patches could effectively improve the healing of wounds in diabetic rats. Overall results indicate that CONP-loaded GelMA hydrogels are highly promising materials for developing clinically relevant patches for treating diabetic wounds.

Bone marrow mesenchymal stem cells preconditioned with nitric-oxide-releasing chitosan/PVA hydrogel accelerate diabetic wound healing in rabbits.

Impaired diabetic wounds are one of the major pathophysiological complications caused by persistent microbial infections, prolonged inflammation, and insufficient angiogenic responses. Here, we report the development of nitric-oxide (NO) -releasing S-nitroso-N-acetyl-penicillamine (SNAP) -loaded chitosan/polyvinyl-alcohol hydrogel and its efficacy in enhancing the wound-healing potential of bone marrow mesenchymal stem cells in diabetic wounds. NO-releasing hydrogels significantly increased the cell viability and cell proliferation of hydrogen-peroxide (H2O2) -pretreated bone marrow stem cells (BMSCs), demonstrating their cytoprotective activity, which was further confirmed by gene expression of many times as much B-cell lymphoma 2 (Bcl-2), stromal cell-derived factor-1alpha (SDF-1α), proliferating cell nuclear antigen (PCNA) and vascular endothelial growth factor (VEGF). Furthermore, the SNAP-loaded hydrogel showed continuous cell-proliferating activity for six days, due to the slow release of NO from the hydrogel. Wound-healing studies of rabbits with induced diabetes showed that the application of SNAP-preconditioned BMSCs and NO-releasing hydrogels significantly sped up the healing process, compared to the control group. The wound-healing potential of BMSCs plus NO-releasing hydrogel was further validated by improved collagen deposition and epithelial layer formation, as confirmed by histopathological examination, as well as upregulation of VEGF and SDF-1α biomarkers, as evidenced by gene-expression analysis. These results demonstrated that the application of BMSCs with NO-releasing hydrogel can promote faster regeneration of damaged tissues. Therefore, BMSCs plus NO-releasing hydrogels can be very useful for the treatment of diabetic wounds.

Electrospun chitosan membranes containing bioactive and therapeutic agents for enhanced wound healing.

Electrospinning is one of the most promising techniques for generating porous, nonwoven, and submicron fiber-based membranes for various applications such as catalysis, sensing, tissue engineering and wound healing. Wide range of biopolymers including chitosan can be used to generate submicron fibrous membranes. Owing to the extra cellular matrix (ECM) mimicking property, exudate uptake capacity, biocompatibility, antibacterial activity and biodegradability, electrospun membranes based on chitosan loaded with biologically active agents can play important role in wound healing applications. In order to improve the mechanical stability, degradation, antimicrobial property, vascularization potential and wound healing capacity, various active components such as other polymers, therapeutic agents, nanoparticles and biomolecules were introduced. Approaches such as coaxial electrospinning with other polymers have also been tried to improve the properties of chitosan membranes. To improve the mechanical stability under in vivo conditions, various crosslinking strategies ranging from physical, chemical and biological approaches were also tried by researchers. Electrospun chitosan meshes have also been designed in a highly specialized manner with specific functionalities to deal with the challenging wound environment of diabetic and burn wounds. This review provides a detailed overview of electrospun chitosan-based membranes containing various bioactive and therapeutic agents in the perspective of wound healing and skin regeneration.

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

PURPOSE: Non-healing or slow healing chronic wounds are among serious complications of diabetes that eventually result in amputation of limbs and increased morbidities and mortalities. Chronic diabetic wounds show reduced blood vessel formation (lack of angiogenesis), inadequate cell proliferation and poor cell migration near wounds. In this paper, we report the development of a hydrogel-based novel wound dressing material loaded with reduced graphene oxide (rGO) to promote cell proliferation, cell migration and angiogenesis for wound healing applications. METHODS: Gelatin-methacryloyl (GelMA) based hydrogels loaded with different concentrations of rGO were fabricated by UV crosslinking. Morphological and physical characterizations (porosity, degradation, and swelling) of rGO incorporated GelMA hydrogel was performed. In vitro cell proliferation, cell viability and cell migration potential of the hydrogels were analyzed by MTT assay, live/dead staining, and wound healing scratch assay respectively. Finally, in vivo chicken embryo angiogenesis (CEO) testing was performed to evaluate the angiogenic potential of the prepared hydrogel. RESULTS: The experimental results showed that the developed hydrogel possessed enough porosity and exudate-absorbing capacity. The biocompatibility of prepared hydrogel on three different cell lines (3T3 fibroblasts, EA.hy926 endothelial cells, and HaCaT keratinocytes) was confirmed by in vitro cell culture studies (live/dead assay). The GelMA hydrogel containing 0.002% w/w rGO considerably increased the proliferation and migration of cells as evident from MTT assay and wound healing scratch assay. Furthermore, rGO impregnated GelMA hydrogel significantly enhanced the angiogenesis in the chick embryo model. CONCLUSION: The positive effect of 0.002% w/w rGO impregnated GelMA hydrogels on angiogenesis, cell migration and cell proliferation suggests that these formulations could be used as a functional wound healing material for the healing of chronic wounds.

CTGF Loaded Electrospun Dual Porous Core-Shell Membrane For Diabetic Wound Healing.

PURPOSE: Impairment of wound healing is a major issue in type-2 diabetes that often causes chronic infections, eventually leading to limb and/or organ amputation. Connective tissue growth factor (CTGF) is a signaling molecule with several roles in tissue repair and regeneration including promoting cell adhesion, cell migration, cell proliferation and angiogenesis. Incorporation of CTGF in a biodegradable core-shell fiber to facilitate its sustained release is a novel approach to promote angiogenesis, cell migration and facilitate wound healing. In this paper, we report the development of CTGF encapsulated electrospun dual porous PLA-PVA core-shell fiber based membranes for diabetic wound healing applications. METHODS: The membranes were fabricated by a core-shell electrospinning technique. CTGF was entrapped within the PVA core which was coated by a thin layer of PLA. The developed membranes were characterized by techniques such as Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) analysis. In vitro cell culture studies using fibroblasts, keratinocytes and endothelial cells were performed to understand the effect of CTGF loaded membranes on cell proliferation, cell viability and cell migration. A chicken chorioallantoic membrane (CAM) assay was performed to determine the angiogenic potential of the membranes. RESULTS: Results showed that the developed membranes were highly porous in morphology with secondary pore formation on the surface of individual fibers. In vitro cell culture studies demonstrated that CTGF loaded core-shell membranes improved cell viability, cell proliferation and cell migration. A sustained release of CTGF from the core-shell fibers was observed for an extended time period. Moreover, the CAM assay showed that core-shell membranes incorporated with CTGF can enhance angiogenesis. CONCLUSION: Owing to the excellent cell proliferation, migration and angiogenic potential of CTGF loaded core-shell PLA-PVA fibrous membranes, they can be used as an excellent wound dressing membrane for treating diabetic wounds and other chronic ulcers.

Nitric oxide releasing chitosan-poly (vinyl alcohol) hydrogel promotes angiogenesis in chick embryo model.

The lack of angiogenic activity is one of the serious complications of chronic wounds associated with delayed wound closure, chronic ulceration, and subsequent limb amputation. Multiple lines of evidence suggest that nitric oxide (NO) produced endogenously by nitric oxide synthase pathway plays a significant role in angiogenic activity and accelerates wounds closure. In this work, chitosan (CS), polyvinyl alcohol (PVA) and S-nitroso-N-acetyl-DL-penicillamine (SNAP) hydrogel was fabricated to accelerate angiogenesis and promote healing in chronic wounds due to better wound closure potential of CS-PVA hydrogel and angiogenic properties of SNAP. The developed CS-PVA hydrogels loaded with SNAP produced a continuous and sustained supply of NO. 3T3 and HaCaT cells showed a significant increase in cell proliferation with 5‰ SNAP loaded CS-PVA hydrogel compared to the control group. Wound scratch assay resulted in four-fold faster recovery of the scratched wound area and an enhanced degree of angiogenic activity was observed in the chick embryo model with the SNAP incorporated CS-PVA hydrogel compared to the control group. The results depict that the use of CS-PVA hydrogel impregnated with SNAP could be a promising material for promoting angiogenesis followed by accelerated healing of the chronic wounds in burns and diabetic patients.

Growth factor releasing core-shell polymeric scaffolds for tissue engineering applications.

Tissue engineering is the use of a combination of cells, biomaterials and appropriate signals to repair or improve the functions of damaged tissues. Our group is exploiting various approaches to effectively encapsulate multiple growth factors in polymeric scaffolds for tissue engineering and wound healing applications. In this report, some of the exciting results from our most recent and ongoing projects are outlined with a focus on the use of connective tissue growth factor (CTGF). CTGF is a secreted protein with major roles in angiogenesis, chondrogenesis, osteogenesis and tissue repair. CTGF can play a major role in tissue regeneration by enhancing cell proliferation and promoting cell migration. CTGF was incorporated to electrospun polymeric fibers to provide sustained release. Experimental results demonstrated the ability of scaffolds incorporated with CTGF to promote cell proliferation and cell migration. This study shows the application potential of the developed scaffolds in various tissue engineering applications.

Reactive Nitrogen Species Releasing Hydrogel for Enhanced Wound Healing.

Poor proliferation and migration of fibroblast, keratinocyte and endothelial cells delays the wound healing in diabetic patients and results into chronicity of wounds. Slow or decreased formation of blood vessels is another issue that increases the chronicity of non-healing wounds. These chronic wounds turn into an ulcer that may lead to limb amputation. Recently, nitric oxide (NO) has emerged as a potential agent for accelerating cell migration and proliferation to enhance wound healing. It increases the expression of necessary angiogenic growth factors which stimulates the proliferation and migration of major cell types involved in wound repair. Here we report the synthesis of chitosan (CS), polyvinyl alcohol (PVA) and a NO donor S-nitroso-N-acetyl-DL-penicillamine (SNAP) to enhance the wound healing activities in chronic wounds. A three-fold increase in the proliferation of 3T3 cells was observed with NO-releasing CS-PVA hydrogels. In vitro cell migration assay demonstrated a four-fold faster migration of cells to the scratched area compared to the control group. The results depict that the use of CS-PVA hydrogel impregnated with the NO donor (SNAP) can be a promising material for promoting cell migration and subsequent accelerated healing of the chronic wounds in burns and diabetic patients.

Graphene Oxide Loaded Hydrogel for Enhanced Wound Healing in Diabetic Patients.

Chronic wound or slow healing of a wound is one of the serious complications in diabetic patients. The decrease in the proliferation and migration of cells such as keratinocytes and fibroblasts is the major reason for the development of such chronic wounds in a diabetic patient. Therefore, designing a wound dressing patch using a biodegradable hydrogel, which can provide a sustained release/delivery of active agents that can support cell proliferation and cell migration, will be highly beneficial for promoting diabetic wound healing. Multiple evidences from both in-vitro and in-vivo studies have shown that graphene oxide (GO) and reduced graphene oxide promote wound healing by promoting migration and proliferation of keratinocyte cells. In addition, GO possesses angiogenic property. Gelatin methacrylate (GelMA) based hydrogels display excellent hydrophilic properties due to the presence of hydrophilic amino, amido, carboxyl, and hydroxyl groups in the polymer chains, which gives them highly porous, soft and flexible structure. In this work, we report the development of hydrogel dressing incorporated with GO to improve wound healing by increasing the proliferation and migration of cells.

Structure and Rheological Properties of Bovine Aortic Heart Valve and Pericardium Tissue: Implications in Bioprosthetic and Tissue-Engineered Heart Valves.

Heart valve (HV) diseases are among the leading causes of cardiac failure and deaths. Of the various HV diseases, damaged HV leaflets are among the primary culprits. In many cases, impaired HV restoration is not always possible, and the replacement of valves becomes necessary. Bioprosthetic HVs have been used for the replacement of the diseased valves, which is obtained from the sources of bovine and porcine origin, while tissue-engineered heart valves (TEHV) have emerged as a promising future solution. The bioprosthetic valves are prone to become calcified, and thus they last for only ten to fifteen years. The adequate understanding of the correlations between the biomechanics and rheological properties of native HV tissues can enable us to improve the durability of the bioprosthetic HV as well as help in the development of tissue-engineered heart valves (TEHV). In this study, the structural and rheological properties of native bovine aortic HV and pericardium tissues were investigated. The microstructures of the tissues were investigated using scanning electron microscopy, while the rheological properties were studied using oscillatory shear measurement and creep test. The reported results provide significant insights into the correlations between the microstructure and viscoelastic properties of the bovine aortic HV and pericardium tissues.