Chitosan/silk fibroin/nitrogen-doped carbon quantum dot/α-tricalcium phosphate nanocomposite electrospinned as a scaffold for wound healing application: In vitro and in vivo studies

Biomimetic Mineralized Hydroxyapatite-Fish-Scale Collagen/Chitosan Nanofibrous Membranes Promote Osteogenesis for Periodontal Tissue Regeneration

Commercial mammalian collagen-based membranes used for guided tissue regeneration (GTR) in periodontal defect repair still face significant challenges, including ethical concerns, cost-effectiveness, and limited capacity for periodontal bone regeneration. Herein, an enhanced biomimetic mineralized hydroxyapatite (HAp)-fish-scale collagen (FCOL)/chitosan (CS) nanofibrous membrane was developed. Specifically, eco-friendly and biocompatible collagen extracted from grass carp fish scales was co-electrospun with CS to produce a biomimetic extracellular matrix membrane. An enhanced biomimetic mineralized HAp coating provided abundant active calcium and phosphate sites, which promoted cell osteogenic differentiation, and showed greater in vivo absorption. In vitro experiments demonstrated that the HAp-FCOL/CS membranes exhibited desirable properties with no cytotoxicity, provided a mimetic microenvironment for stem cell recruitment, and induced periodontal ligament cell osteogenic differentiation. In rat periodontal defects, HAp-FCOL/CS membranes significantly promoted new periodontal bone formation and regeneration. The results of this study indicate that low-cost, eco-friendly, and biomimetic HAp-FCOL/CS membranes could be promising alternatives to GTR membranes for periodontal regeneration in the clinic.

Comparative Analysis of Electrospun Silk Fibroin/Chitosan Sandwich-Structured Scaffolds for Osteo Regeneration: Evaluating Mechanical Properties, Biological Performance, and Drug Release

An intensive idea of bone tissue engineering is to design regenerative nanofibrous scaffolds that could afford a natural extracellular matrix (ECM) microenvironment with the ability to induce cell proliferation, biodegradation, sustained drug release, and bioactivity. Even the mechanical properties and orientation of the nanofibers may enhance the performance of the scaffolds. To address this issue, we designed novel sandwich-like hybrid silk fibroin (SF)/silica/poly(vinyl alcohol) (PVA) nanofibers scaffolds. The developed scaffold was further characterized using scanning electron microscopy (SEM), elemental mapping, X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and water/blood contact angle measurements. Owing to the interfacial interaction between the layers of organic (chitosan/silk fibroin) and inorganic (silica) in the nanofibrous scaffold, a biocompatibility study has been made on an osteoblast-like (MG63) cell line, which has significant statistical differences; hemocompatibility and the mechanical profile were evaluated in detail to understand the suitability as a biomaterial. To endow the scaffold biodegradation rate, antibacterial activity, porosity profile, and cephalexin monohydrate (CEM), a drug-loading/drug release study was also performed for all of the nanofibers. This strategy explored superior mechanical strength with higher biomineralization on SF/silica/PVA nanofibers. Eventually, the proposed article compared the observation of monolayered scaffolds with designed sandwich-structured scaffolds for the enhancement of bone regeneration.

Calcium Orthophosphate (CaPO4) Containing Composites for Biomedical Applications: Formulations, Properties, and Applications

The goal of this review is to present a wide range of hybrid formulations and composites containing calcium orthophosphates (abbreviated as CaPO4) that are suitable for use in biomedical applications and currently on the market. The bioactive, biocompatible, and osteoconductive properties of various CaPO4-based formulations make them valuable in the rapidly developing field of biomedical research, both in vitro and in vivo. Due to the brittleness of CaPO4, it is essential to combine the desired osteologic properties of ceramic CaPO4 with those of other compounds to create novel, multifunctional bone graft biomaterials. Consequently, this analysis offers a thorough overview of the hybrid formulations and CaPO4-based composites that are currently known. To do this, a comprehensive search of the literature on the subject was carried out in all significant databases to extract pertinent papers. There have been many formulations found with different material compositions, production methods, structural and bioactive features, and in vitro and in vivo properties. When these formulations contain additional biofunctional ingredients, such as drugs, proteins, enzymes, or antibacterial agents, they offer improved biomedical applications. Moreover, a lot of these formulations allow cell loading and promote the development of smart formulations based on CaPO4. This evaluation also discusses basic problems and scientific difficulties that call for more investigation and advancements. It also indicates perspectives for the future.

Composite Aerogel Scaffolds Containing Flexible Silica Nanofiber and Tricalcium Phosphate Enable Skin Regeneration

Poor hemostatic ability and less vascularization at the injury site could hinder wound healing as well as adversely affect the quality of life (QOL). An ideal wound dressing should exhibit certain characteristics: (a) good hemostatic ability, (b) rapid wound healing, and (c) skin appendage formation. This necessitates the advent of innovative dressings to facilitate skin regeneration. Therapeutic ions, such as silicon ions (Si4+) and calcium ions (Ca2+), have been shown to assist in wound repair. The Si4+ released from silica (SiO2) can upregulate the expression of proteins, including the vascular endothelial growth factor (VEGF) and alpha smooth muscle actin (α-SMA), which is conducive to vascularization; Ca2+ released from tricalcium phosphate (TCP) can promote the coagulation alongside upregulating the expression of cell migration and cell differentiation related proteins, thereby facilitating the wound repair. The overarching objective of this study was to exploit short SiO2 nanofibers along with the TCP to prepare TCPx@SSF aerogels and assess their wound healing ability. Short SiO2 nanofibers were prepared by electrospinning and blended with varying proportions of TCP to afford TCPx@SSF aerogel scaffolds. The TCPx@SSF aerogels exhibited good cytocompatibility in a subcutaneous implantation model and manifested a rapid hemostatic effect (hemostatic time 75 s) in a liver trauma model in the rabbit. These aerogel scaffolds also promoted skin regeneration and exhibited rapid wound closure, epithelial tissue regeneration, and collagen deposition. Taken together, TCPx@SSF aerogels may be valuable for wound healing.

Silk fibroin-based scaffolds for tissue engineering

Silk fibroin is an important natural fibrous protein with excellent prospects for tissue engineering applications. With profound studies in recent years, its potential in tissue repair has been developed. A growing body of literature has investigated various fabricating methods of silk fibroin and their application in tissue repair. The purpose of this paper is to trace the latest developments of SF-based scaffolds for tissue engineering. In this review, we first presented the primary and secondary structures of silk fibroin. The processing methods of SF scaffolds were then summarized. Lastly, we examined the contribution of new studies applying SF as scaffolds in tissue regeneration applications. Overall, this review showed the latest progress in the fabrication and utilization of silk fibroin-based scaffolds.

Recent advances of silk fibroin materials: From molecular modification and matrix enhancement to possible encapsulation-related functional food applications

Silk fibroin materials are emergingly explored for food applications due to their inherent properties including safe oral consumption, biocompatibility, gelatinization, antioxidant performance, and mechanical properties. However, silk fibroin possesses drawbacks like brittleness owing to its inherent specific composition and structure, which limit their applications in this field. This review discusses current progress about molecular modification methods on silk fibroin such as extraction, blending, self-assembly, enzymatic catalysis, etc., to address these limitations and improve their physical/chemical properties. It also summarizes matrix enhancement strategies including freeze drying, spray drying, electrospinning/electrospraying, microfluidic spinning/wheel spinning, desolvation and supercritical fluid, to generate nano-, submicron-, micron-, or bulk-scale materials. It finally highlights the food applications of silk fibroin materials, including nutraceutical improvement, emulsions, enzyme immobilization and 3D/4D printing. This review also provides insights on potential opportunities (like safe modification, toxicity risk evaluation, and digestion conditions) and possibilities (like digital additive manufacturing) in functional food industry.

Silk fibroin/methacrylated gelatine/hydroxyapatite biomimetic nanofibrous membranes for guided bone regeneration

By mimicking in vivo bionic microenvironment and promoting osteogenic differentiation, the hybrid organic-inorganic nanofibrous membranes provide promising potential for guided bone regeneration (GBR) in the treatment of clinical bone defects. To develop a degradable and osteogenic membrane for GBR by combining the natural biomacromolecule silk fibroin (SF) and gelatine with the bioactive nano hydroxyapatite (nHA), the anhydride-modified gelatine-nano hydroxyapatite (GelMA-nHA) composites were synthesized in situ and introduced into silk fibroin to prepare nanofibrous membranes with different ratios using electrospinning and photocrosslinking. The nanofibrous membranes, particularly those with a mass ratio of 7:2:1, were found to exhibit satisfactory elongation at break up to 110 %, maintain the nanofibrous structure for up to 28 days, and rapidly form bone-like apatite within 3 days, thus offering advantages when it comes to guided bone regeneration. In vitro cell results showed that the SF/GelMA/nHA membranes had excellent biocompatibility and enhanced osteogenic differentiation of hBMSCs. In vivo studies revealed that the hybrid composite membranes can improve bone regeneration of critical-sized calvarial defects in rat model. Therefore, the novel hybrid nanofibrous membrane is proposed to be a alternative candidate for creating a bionic microenvironment that promotes bone regeneration, indicating their potential application to bone injury treatment.

A comparative study of structural and catalytic activity alterations in firefly luciferase induced by carbon quantum dots containing amine and carboxyl functional groups

Despite of growing interest in use of carbon-based nanomaterials as carriers of functional proteins, less attention has been paid to the effects of these nanomaterials on the structure and function of the proteins. In this study, with the aim of shedding light on the mechanisms of interaction between carbon-based nanomaterials and proteins, the interactions of carbon quantum dots (CQDs) containing amine (CQD-NH2) or carboxyl groups (CQD-COOH) with Photinus pyralis firefly luciferase enzyme were investigated by experimental and computational approaches. The structural changes and reduction in activity of the luciferase upon treatment with CQDs were experimentally proved. CQD-NH2 induced more reduction in enzyme activity (15 %) compared to CQD-COOH (7.4 %). The interactions CQD-NH2 with luciferase led to higher affinity of the enzyme for its substrate. It was found by molecular dynamic simulations that CQD-NH2 binds to multiple regions on the surface of luciferase. Secondary structure analysis showed that CQD-NH2 had more profound effects on the active site amino acids, the adjacent amino acids to the active site and the residues involved in ATP binding site. In addition, CQD-NH2 interactions with luciferase were suggested to be stronger than CQD-COOH based on the number of hydrogen bonds and the binding energies.

Functional electrospun nanofibers: fabrication, properties, and applications in wound-healing process

Electrostatic spinning as a technique for producing nanoscale fibers has recently attracted increasing attention due to its simplicity, versatility, and loadability. Nanofibers prepared by electrostatic spinning have been widely studied, especially in biomedical applications, because of their high specific surface area, high porosity, easy size control, and easy surface functionalization. Wound healing is a highly complex and dynamic process that is a crucial step in the body's healing process to recover from tissue injury or other forms of damage. Single-component nanofibers are more or less limited in terms of structural properties and do not fully satisfy various needs of the materials. This review aims to provide an in-depth analysis of the literature on the use of electrostatically spun nanofibers to promote wound healing, to overview the infinite possibilities for researchers to tap into their biomedical applications through functional composite modification of nanofibers for advanced and multifunctional materials, and to propose directions and perspectives for future research.

Silk fibroin-derived electrospun materials for biomedical applications: A review

Electrospinning is a versatile technique for fabricating polymeric fibers with diameters ranging from micro- to nanoscale, exhibiting multiple morphologies and arrangements. By combining silk fibroin (SF) with synthetic and/or natural polymers, electrospun materials with outstanding biological, chemical, electrical, physical, mechanical, and optical properties can be achieved, fulfilling the evolving biomedical demands. This review highlights the remarkable versatility of SF-derived electrospun materials, specifically focusing on their application in tissue regeneration (including cartilage, cornea, nerves, blood vessels, bones, and skin), disease treatment (such as cancer and diabetes), and the development of controlled drug delivery systems. Additionally, we explore the potential future trends in utilizing these nanofibrous materials for creating intelligent biomaterials, incorporating biosensors and wearable sensors for monitoring human health, and also discuss the bottlenecks for its widespread use. This comprehensive overview illuminates the significant impact and exciting prospects of SF-derived electrospun materials in advancing biomedical research and applications.

Electrospun fibers for the treatment of skin diseases

Skin diseases are among the most common diseases in the global population and with the growth of the aging population, they represent an increasing burden to healthcare systems worldwide. Even though they are rarely life-threatening, the suffering for those affected is high due to the visibility and physical discomfort related to these diseases. Typical symptoms of skin diseases include an inflamed, swollen or itchy skin, and therefore, there is a high demand for effective therapy options. In recent years, electrospinning has attracted considerable interest in the field of drug delivery. The technique allows producing multifunctional drug-loaded fibrous patches from various natural and synthetic polymers with fiber diameters in the nano- and micrometer range, suitable for the treatment of a wide variety of skin diseases. The great potential of electrospun fiber patches not only lies in their tunable drug release properties and the possibility to entrap a variety of therapeutic compounds, but they also provide physical and mechanical protection to the impaired skin area, exhibit a high surface area, allow gas exchange, absorb exudate due to their porous structure and are cytocompatible and biodegradable. In the case of wound healing, cell adhesion is promoted due to the resemblance of the electrospun fibers to the structure of the native extracellular matrix. This review gives an overview of the potential applications of electrospun fibers in skin therapy. In addition to the treatment of bacterial, diabetic and burn wounds, focus is placed on inflammatory diseases such as atopic dermatitis and psoriasis, and therapeutic options for the treatment of skin cancer, acne vulgaris and herpes labialis are discussed. While we aim to emphasize the great potential of electrospun fiber patches for the treatment of skin diseases with this review paper, we also highlight challenges and limitations of current research in the field.

Peptides Targeting HER2-Positive Breast Cancer Cells and Applications in Tumor Imaging and Delivery of Chemotherapeutics

Breast cancer represents the most common cancer type and one of the major leading causes of death in the female worldwide population. Overexpression of HER2, a transmembrane glycoprotein related to the epidermal growth factor receptor, results in a biologically and clinically aggressive breast cancer subtype. It is also the primary driver for tumor detection and progression and, in addition to being an important prognostic factor in women diagnosed with breast cancer, HER2 is a widely known therapeutic target for drug development. The aim of this review is to provide an updated overview of the main approaches for the diagnosis and treatment of HER2-positive breast cancer proposed in the literature over the past decade. We focused on the different targeting strategies involving antibodies and peptides that have been explored with their relative outcomes and current limitations that need to be improved. The review also encompasses a discussion on targeted peptides acting as probes for molecular imaging. By using different types of HER2-targeting strategies, nanotechnology promises to overcome some of the current clinical challenges by developing novel HER2-guided nanosystems suitable as powerful tools in breast cancer imaging, targeting, and therapy.

Recent Progress and Trends in the Development of Electrospun and 3D Printed Polymeric-Based Materials to Overcome Antimicrobial Resistance (AMR)

Antimicrobial resistance (AMR) developed by microorganisms is considered one of the most critical public health issues worldwide. This problem is affecting the lives of millions of people and needs to be addressed promptly. Mainly, antibiotics are the substances that contribute to AMR in various strains of bacteria and other microorganisms, leading to infectious diseases that cannot be effectively treated. To avoid the use of antibiotics and similar drugs, several approaches have gained attention in the fields of materials science and engineering as well as pharmaceutics over the past five years. Our focus lies on the design and manufacture of polymeric-based materials capable of incorporating antimicrobial agents excluding the aforementioned substances. In this sense, two of the emerging techniques for materials fabrication, namely, electrospinning and 3D printing, have gained significant attraction. In this article, we provide a summary of the most important findings that contribute to the development of antimicrobial systems using these technologies to incorporate various types of nanomaterials, organic molecules, or natural compounds with the required property. Furthermore, we discuss and consider the challenges that lie ahead in this research field for the coming years.

Electrospun Nanofibrous Mesh Based on PVA, Chitosan, and Usnic Acid for Applications in Wound Healing

Injuries and diseases of the skin require accurate treatment using nontoxic and noninvasive biomaterials, which aim to mimic the natural structures of the body. There is a strong need to develop biodevices capable of accommodating nutrients and bioactive molecules and generating the process of vascularization. Electrospinning is a robust technique, as it can form fibrous structures for tissue engineering and wound dressings. The best way of forming such meshes for wound healing is to choose two polymers that complement each other regarding their properties. On the one hand, PVA is a water-soluble synthetic polymer widely used for the preparation of hydrogels in the field of biomedicine owing to its biocompatibility, water solubility, nontoxicity, and considerable mechanical properties. PVA is easy to subject to electrospinning and can offer strong mechanical stability of the mesh, but it is necessary to improve its biological properties. On the other hand, CS has good biological properties, including biodegradability, nontoxicity, biocompatibility, and antimicrobial properties. Still, it is harder to electrospin and does not possess as good mechanical properties as PVA. As these structures also allow the incorporation of bioactive agents due to their high surface-area-to-volume ratio, the interesting point was to incorporate usnic acid into the structure as it is a natural and suitable alternative agent for burn wounds treatment which avoids an improper or overuse of antibiotics and other invasive biomolecules. Thus, we report the fabrication of an electrospun nanofibrous mesh based on PVA, chitosan, and usnic acid with applications in wound healing. The obtained nanofibers mesh was physicochemically characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). In vitro biological assays were performed to evaluate the antimicrobial properties of the samples using the MIC (minimum inhibitory concentration) assay and evaluating the influence of fabricated meshes on the Staphylococcus aureus biofilm development, as well as their biocompatibility (demonstrated by fluorescence microscopy results, an XTT assay, and a glutathione (GSH) assay).

Nanofiber Scaffolds as Drug Delivery Systems Promoting Wound Healing

Nanofiber scaffolds have emerged as a revolutionary drug delivery platform for promoting wound healing, due to their unique properties, including high surface area, interconnected porosity, excellent breathability, and moisture absorption, as well as their spatial structure which mimics the extracellular matrix. However, the use of nanofibers to achieve controlled drug loading and release still presents many challenges, with ongoing research still exploring how to load drugs onto nanofiber scaffolds without loss of activity and how to control their release in a specific spatiotemporal manner. This comprehensive study systematically reviews the applications and recent advances related to drug-laden nanofiber scaffolds for skin-wound management. First, we introduce commonly used methods for nanofiber preparation, including electrostatic spinning, sol-gel, molecular self-assembly, thermally induced phase separation, and 3D-printing techniques. Next, we summarize the polymers used in the preparation of nanofibers and drug delivery methods utilizing nanofiber scaffolds. We then review the application of drug-loaded nanofiber scaffolds for wound healing, considering the different stages of wound healing in which the drug acts. Finally, we briefly describe stimulus-responsive drug delivery schemes for nanofiber scaffolds, as well as other exciting drug delivery systems.