Advances in Electrospun Hybrid Nanofibers for Biomedical Applications

Silver nanoparticles loaded triple-layered cellulose-acetate based multifunctional dressing for wound healing

Chronic wounds present considerable challenges which delay their effective healing. Currently, there are several biomaterial-based wound dressings available for healing diverse wound types. However, most of commercial wound dressings are too expensive to be affordable to the patients belonging to the middle and lower socioeconomic strata of the society. Thus, in this investigation affordable triple layered nanofibrous bandages were fabricated using the layer-by-layer approach. Here, the topmost layer comprised of a hydrophilic poly vinyl alcohol layer, cross-linked with citric acid. The middle layer comprising of cellulose acetate was loaded with silver nanoparticles as an antibacterial agent, while the lowermost layer was fabricated using hydrophobic polycaprolactone. The triple-layered nanofibrous bandages having a nano-topography, exhibited a smooth, uniform and bead-free morphology, with the nanofiber diameter ranging between 200 and 300 nm. The nanofibers demonstrated excellent wettability, slow in vitro degradation, controlled release of nano‑silver and potent antibacterial activity against Gram-negative (E.coli) and Gram-positive (S. aureus) bacteria. The fabricated bandages had excellent mechanical strength upto 12.72 ± 0.790 M. Pa, which was suitable for biomedical and tissue engineering applications. The bandage demonstrated excellent in vitro hemocompatibility and biocompatibility. In vivo excisional wound contraction, along with H and E and Masson's Trichrome staining further confirmed the potential of the nanofibrous bandage for full-thickness wound healing. Pre-clinical investigations thus indicated the possibility of further evaluating the triple-layered nanofibrous dressing in clinical settings.

Recent advances in modifications of exudate gums: Functional properties and applications

Gums are high-molecular-weight compounds with hydrophobic or hydrophilic characteristics, which are mainly comprised of complex carbohydrates called polysaccharides, often associated with proteins and minerals. Various innovative modification techniques are utilized, including ultrasound-assisted and microwave-assisted techniques, enzymatic alterations, electrospinning, irradiation, and amalgamation process. These methods advance the process, reducing processing times and energy consumption while maintaining the quality of the modified gums. Enzymes like xanthan lyases, xanthanase, and cellulase can selectively modify exudate gums, altering their structure to enhance their properties. This precise enzymatic approach allows for the use of exudate gums for specific applications. Exudate gums have been employed in nanotechnology applications through techniques like electrospinning. This enables the production of nanoparticles and nanofibers with improved properties, making them suitable for the drug delivery system, tissue engineering, active and intelligient food packaging. The resulting modified exudate gums exhibit improved rheological, emulsifying, gelling, and other functional properties, which expand their potential applications. This paper discusses novel applications of these modified gums in the pharmaceutical, food, and industrial sectors. The ever-evolving field presents diverse opportunities for sustainable innovation across these sectors.

Formation mechanism of a novel core-shell with tetradecyl dimethyl benzyl ammonium-modified montmorillonite interlayer nanofibrous membrane and its antimicrobial properties

A novel core-shell with a tetradecyl dimethyl benzyl ammonium chloride-modified montmorillonite (TDMBA/MMT) interlayer silk fibroin (SF)/poly(lactic acid) (PLLA) nanofibrous membrane was fabricated using a simple conventional electrospinning method. Scanning electron microscopy and pore size analyses revealed that this core-shell with TDMBA/MMT interlayer maintained its nanofibrous morphology and larger pore structure more successfully than SF/PLLA nanofibrous membranes after treatment with 75% ethanol vapor. Transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses testified that the SF/PLLA-TDMBA/MMT nanofibers exhibited a core-shell with an interlayer structure, with SF/PLLA in the core-shell layer and TDMBA/MMT in the interlayer. The formation of a core-shell with interlayer nanofibers was primarily attributed to the uniform dispersion of TDMBA/MMT nanosheets in a solution owing to its exfoliation using hexafluoroisopropanol and then preparing a stable spinning solution similar to an emulsion. Compared to SF/PLLA nanofibrous membranes, the core-shell structure with TDMBA/MMT interlayers of SF/PLLA nanofibrous membranes exhibited enhanced hydrophilicity, thermal stability, mechanical properties as well as improved and long-lasting antimicrobial performance against Escherichia coli and Staphylococcus aureus without cytotoxicity.

Dendronized Ag/Au Nanomats: Antimicrobial Scaffold for Wound Healing Bandages

Electrospun polymer nanofibers, due to high surface area-to-volume ratio, high porosity, good mechanical strength, and ease of functionalization, appear as promising multifunctional materials for biomedical applications. Thanks to their unidirectional structure, imitating the extracellular matrix (ECM), they can be used as scaffolds for cell adhesion and proliferation. In addition, the incorporation of active groups inside nanofiber can give properties for bactericides. The proposed nanomats incorporate nanoparticles templated within the electrospun nanofibers that prevent infections and stimulate tissue regeneration. The generated hybrid electrospun nanofibers are composed of a copolymer of L-lactide-block-ε-caprolactone (PL-b-CL), 70:30, blended with homopolymer polyvinylpyrrolidone (PVP) and gold (Au) nanoparticles. A low cytotoxicity and slightly increased immunoreactivity, stimulated by the nanomat, are observed. Moreover, the decoration of the hybrid nanomat with dendronized silver nanoparticles (Dend-Ag) improves their antibacterial activity against antibiotic-resistant Pseudomonas aeruginosa. The use of Dend-Ag for decorating offers several functional effects; namely, it enhances the antibacterial properties of the produced nanomats and induces a significant increase within macrophages' cytotoxicity. The unidirectional nanostructures of the generated hybrid nanomats demonstrate unique collective physio-chemical and biological properties suitable for a wide range of biomedical applications. Here, the antibacterial properties facilitate an optimal environment, contributing to accelerated wound healing.

Biodegradable Electrospun Membranes for Sustainable Industrial Applications

The escalating demand for sustainable industrial practices has driven the exploration of innovative materials, prominently exemplified by biodegradable electrospun membranes (BEMs). This review elucidates the pivotal role of these membranes across diverse industrial applications, addressing the imperative for sustainability. Furthermore, a comprehensive overview of biodegradable materials underscores their significance in electrospinning and their role in minimizing the environmental impact through biodegradability. The application of BEMs in various industrial sectors, including water treatment, food packaging, and biomedical applications, are extensively discussed. The environmental impact and sustainability analysis traverse the lifecycle of BEMs, evaluating their production to disposal and emphasizing reduced waste and resource conservation. This review demonstrates the research about BEMs toward an eco-conscious industrial landscape for a sustainable future.

Electrospun Core-Sheath Nanofibers with a Cellulose Acetate Coating for the Synergistic Release of Zinc Ion and Drugs

Precisely modulating the synergistic release behavior of multiple bioactive substances has emerged as a formidable challenge in recent years. In this work, we successfully prepared core-sheath nanofibers, where a thin cellulose acetate (CA) coating enrobed the core. Curcumin (Cur) was encapsulated in the core layer as a model drug, while zinc oxide (ZnO) nanoparticles were loaded on the sheath layer. The prepared fiber exhibited a straight cylindrical morphology containing nanoparticles, and the distinct core-sheath nanostructure was demonstrated through transmission electron microscopy (TEM). X-ray diffraction (XRD) and Fourier transform infrared (FTIR) were conducted to study the physical state and compatibility among CA, Cur, and ZnO. Drug release data indicated that core-sheath nanofibers were able to decelerate the rate of drug release, and the thickness of the sheath layer increased in the presence of ZnO particles. Most remarkably, these core-sheath nanofibers exhibited the remarkable ability to sustain the release of drugs and zinc ion (Zn2+), the two-day synergistically release behavior leading to a significant increase in cell proliferation. This material preparation strategy for the synergistic and controlled release of two bioactive substances is instructive for the exploration of innovative and versatile drug delivery systems.

Biodegradable Polymers in Biomedical Applications: A Review-Developments, Perspectives and Future Challenges

Biodegradable polymers are materials that, thanks to their remarkable properties, are widely understood to be suitable for use in scientific fields such as tissue engineering and materials engineering. Due to the alarming increase in the number of diagnosed diseases and conditions, polymers are of great interest in biomedical applications especially. The use of biodegradable polymers in biomedicine is constantly expanding. The application of new techniques or the improvement of existing ones makes it possible to produce materials with desired properties, such as mechanical strength, controlled degradation time and rate and antibacterial and antimicrobial properties. In addition, these materials can take virtually unlimited shapes as a result of appropriate design. This is additionally desirable when it is necessary to develop new structures that support or restore the proper functioning of systems in the body.

Hybrid Nanomat: Copolymer Template CdSe Quantum Dots In Situ Stabilized and Immobilized within Nanofiber Matrix

Fabrication and characterization of hybrid nanomats containing quantum dots can play a prominent role in the development of advanced biosensors and bio-based semiconductors. Owing to their size-dependent properties and controlled nanostructures, quantum dots (QDs) exhibit distinct optical and electronic characteristics. However, QDs include heavy metals and often require stabilizing agents which are toxic for biological applications. Here, to mitigate the use of toxic ligands, cadmium selenide quantum dots (CdSe QDs) were synthesized in situ with polyvinylpyrrolidone (PVP) at room temperature. The addition of PVP polymer provided size regulation, stability, and control over size distribution of CdSe QDs. The characterization of the optical properties of the CdSe QDs was performed using fluorescence and ultraviolet-visible (UV-Vis) spectroscopy. CdSe QDs exhibited a typical absorbance peak at 280 nm and a photoluminescence emission peak at 580 nm. Transmission electron microscopy (TEM) micrographs demonstrated that CdSe QDs having an average size of 6 ± 4 nm were obtained via wet chemistry method. CdSe QDs were immobilized in a blend of PVP and poly(L-lactide-co-ε-caprolactone) (PL-b-CL) copolymer that was electrospun to produce nanofibers. Scanning electron microscopy (SEM), thermal analyses and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) were used to characterize properties of fabricated nanofibers. Both pristine and hybrid nanofibers possessed cylindrical geometry and rough surface features, facilitating increased surface area. Infrared absorption spectra showed a slight shift in absorbance peaks due to interaction of PVP-coated CdSe QDs and nanofiber matrix. The presence of CdSe QDs influenced the fiber diameter and their thermal stability. Further, in vitro biological analyses of hybrid nanofibers showed promising antibacterial effect and decline in cancer cell viability. This study offers a simple approach to obtain hybrid nanomats immobilized with size-controlled PVP-coated CdSe QDs, which have potential applications as biosensors and antibacterial and anticancer cell agents.

Electrohydrodynamic Techniques for the Manufacture and/or Immobilization of Vesicles

The development of accurate drug delivery systems is one of the main challenges in the biomedical field. A huge variety of structures, such as vesicles, nanoparticles, and nanofibers, have been proposed as carriers for bioactive agents, aiming for precision in administration and dosage, safety, and bioavailability. This review covers the use of electrohydrodynamic techniques both for the immobilization and for the synthesis of vesicles in a non-conventional way. The state of the art discusses the most recent advances in this field as well as the advantages and limitations of electrospun and electrosprayed amphiphilic structures as precursor templates for the in situ vesicle self-assembly. Finally, the perspectives and challenges of combined strategies for the development of advanced structures for the delivery of bioactive agents are analyzed.

Electrospun hybrid nanofibers: Fabrication, characterization, and biomedical applications

Nanotechnology is one of the most promising technologies available today, holding tremendous potential for biomedical and healthcare applications. In this field, there is an increasing interest in the use of polymeric micro/nanofibers for the construction of biomedical structures. Due to its potential applications in various fields like pharmaceutics and biomedicine, the electrospinning process has gained considerable attention for producing nano-sized fibers. Electrospun nanofiber membranes have been used in drug delivery, controlled drug release, regenerative medicine, tissue engineering, biosensing, stent coating, implants, cosmetics, facial masks, and theranostics. Various natural and synthetic polymers have been successfully electrospun into ultrafine fibers. Although biopolymers demonstrate exciting properties such as good biocompatibility, non-toxicity, and biodegradability, they possess poor mechanical properties. Hybrid nanofibers from bio and synthetic nanofibers combine the characteristics of biopolymers with those of synthetic polymers, such as high mechanical strength and stability. In addition, a variety of functional agents, such as nanoparticles and biomolecules, can be incorporated into nanofibers to create multifunctional hybrid nanofibers. Due to the remarkable properties of hybrid nanofibers, the latest research on the unique properties of hybrid nanofibers is highlighted in this study. Moreover, various established hybrid nanofiber fabrication techniques, especially the electrospinning-based methods, as well as emerging strategies for the characterization of hybrid nanofibers, are summarized. Finally, the development and application of electrospun hybrid nanofibers in biomedical applications are discussed.