Conductive conduit based on electrospun poly (l-lactide-co-D, l-lactide) nanofibers containing 4-aminopyridine-loaded molecularly imprinted poly (methacrylic acid) nanoparticles used for peripheral nerve regeneration

Nanomaterial-functionalized electrospun scaffolds for tissue engineering

Tissue engineering has emerged as a biological alternative aimed at sustaining, rehabilitating, or enhancing the functionality of tissues that have experienced partial or complete loss of their operational capabilities. The distinctive characteristics of electrospun nanofibrous structures, such as their elevated surface-area-to-volume ratio, specific pore sizes, and fine fiber diameters, make them suitable as effective scaffolds in tissue engineering, capable of mimicking the functions of the targeted tissue. However, electrospun nanofibers, whether derived from natural or synthetic polymers or their combinations, often fall short of replicating the multifunctional attributes of the extracellular matrix (ECM). To address this, nanomaterials (NMs) are integrated into the electrospun polymeric matrix through various functionalization techniques to enhance their multifunctional properties. Incorporation of NMs into electrospun nanofibrous scaffolds imparts unique features, including a high surface area, superior mechanical properties, compositional variety, structural adaptability, exceptional porosity, and enhanced capabilities for promoting cell migration and proliferation. This review provides a comprehensive overview of the various types of NMs, the methodologies used for their integration into electrospun nanofibrous scaffolds, and the recent advancements in NM-functionalized electrospun nanofibrous scaffolds aimed at regenerating bone, cardiac, cartilage, nerve, and vascular tissues. Moreover, the main challenges, limitations, and prospects in electrospun nanofibrous scaffolds are elaborated.

Enhanced Antibacterial Activity of Clindamycin Using Molecularly Imprinted Polymer Nanoparticles Loaded with Polyurethane Nanofibrous Scaffolds for the Treatment of Acne Vulgaris

Acne vulgaris, a prevalent skin condition, arises from an imbalance in skin flora, fostering bacterial overgrowth. Addressing this issue, clindamycin molecularly imprinted polymeric nanoparticles (Clin-MIP) loaded onto polyurethane nanofiber scaffolds were developed for acne treatment. Clin-MIP was synthesized via precipitation polymerization using methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), and azoisobutyronitrile (AIBN) as functional monomers, crosslinkers, and free-radical initiators, respectively. MIP characterization utilized Fourier-transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) before being incorporated into polyurethane nanofibers through electrospinning. Further analysis involved FTIR, scanning electron microscopy (SEM), in vitro release studies, and an ex vivo study. Clin-MIP showed strong antibacterial activity against S. aureus, with inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.39 and 6.25 μg/mL, respectively. It significantly dropped the bacterial count from 1 × 108 to 39 × 101 CFU/mL in vivo and has bactericidal activity within 180 min of incubation in vitro. The pharmacodynamic and histopathology studies revealed a significant decrease in infected animal skin inflammation, epidermal hypertrophy, and congestion upon treatment with Clin-MIP polyurethane nanofiber and reduced pro-inflammatory cytokines (NLRP3, TNF-α, IL-1β, and IL-6) conducive to acne healing. Consequently, the recently created Clin-MIP polyurethane nanofibrous scaffold. This innovative approach offers insight into creating materials with several uses for treating infectious wounds caused by acne.

Improvement of Intracellular Interactions through Liquid Crystalline Elastomer Scaffolds by the Alteration of Topology

Preparation of inherently bioactive scaffolds has become a challenging issue owing to their complicated synthesis and nonrobust modified cell-actuating property. Liquid crystalline elastomers (LCEs), due to their combined specialties of liquid crystals and elastomers as well as their ability to respond to various kinds of stimuli, have reversibly led to the design of a new class of stimuli-responsive tissue-engineered scaffolds. In this line, in the first stage of this research work, synthesis and evaluation of acrylate-based LCE films (LCEfilm) encompassing mesogenic monomers are carried out. In the second step, the design of an affordable electrospinning technique for preparing LCE nanofibers (LCEfiber) as a problematic topic, thanks to the low molecular weight of the mesogenic chains of LCEs, is investigated. For this purpose, two approaches are considered, including (1) photo-cross-linking of electrospun LCEfiber and (2) blending LCE with poly(ε-caprolactone) (PCL) to produce morphologically stable nanofibers (PCL-LCEfiber). In the following, thermal, mechanical, and morphological evaluations show the optimized crosslinker (mol)/aliphatic spacer (mol) molar ratio of 50:50 for LCEfilm samples. On the other hand, for LCEfiber samples, the appropriate amounts of excessive mesogenic monomer and PCL/LCE (v/v) to fabricate the uniform nanofibers are determined to be 20% and 1:2, respectively. Eventually, PC12 cell compatibility and the impact of the liquid crystalline phase on the PC12 cell dynamic behavior of the samples are examined. The obtained results reveal that PC12 cells cultured on electrospun PCL-LCEfiber nanofibers with an average diameter of ∼659 nm per sample are alive and the scaffold has susceptibility for cell proliferation and actuation because of the rapid increase in cell density and number of singularity points formed in time-lapse cell imaging. Moreover, the PCL-LCEfiber nanofibrous scaffold exhibits a high performance for cell differentiation according to detailed biological evaluations such as gene expression level measurements. The time-lapse evaluation of PC12 cell flow fields confirms the significant influence of the reprogrammable liquid crystalline phase in the PCL-LCEfiber nanofibrous scaffold on topographical cue induction compared to the biodegradable PCL nanofibers.

How Advancing is Peripheral Nerve Regeneration Using Nanofiber Scaffolds? A Comprehensive Review of the Literature

Peripheral nerve injuries present significant challenges in regenerative medicine, primarily due to inherent limitations in the body's natural healing processes. In response to these challenges and with the aim of enhancing peripheral nerve regeneration, nanofiber scaffolds have emerged as a promising and advanced intervention. However, a deeper understanding of the underlying mechanistic foundations that drive the favorable contributions of nanofiber scaffolds to nerve regeneration is essential. In this comprehensive review, we make an exploration of the latent potential of nanofiber scaffolds in augmenting peripheral nerve regeneration. This exploration includes a detailed introduction to the fabrication methods of nanofibers, an analysis of the intricate interactions between these scaffolds and cellular entities, an examination of strategies related to the controlled release of bioactive agents, an assessment of the prospects for clinical translation, an exploration of emerging trends, and thorough considerations regarding biocompatibility and safety. By comprehensively elucidating the intricate structural attributes and multifaceted functional capacities inherent in nanofiber scaffolds, we aim to offer a prospective and effective strategy for the treatment of peripheral nerve injury.

Electrospun Piezoelectric Scaffold with External Mechanical Stimulation for Promoting Regeneration of Peripheral Nerve Injury

Safe and efficient provision of electrical stimulation (ES) for nerve repair and regeneration is a problem that needs to be addressed. In this study, a silk fibroin/poly(vinylidene fluoride-co-hexafluoropropylene)/Ti₃C₂T_x (SF/PVDF-HFP/MXene) composite scaffold with piezoelectricity was developed by electrospinning technology. MXene was loaded to the scaffold to enhance the piezoelectric properties (Output voltage reaches up to 100 mV), mechanical properties, and antibacterial activity. Cell experiments demonstrated piezoelectric stimulation under external ultrasonication for promoting the growth and proliferation of Schwann cells (SCs) cultured on this electrospun scaffold. Further in vivo study with rat sciatic nerve injury model revealed that the SF/PVDF-HFP/MXene nerve conduit could induce the proliferation of SCs, enhance the elongation of axon, and promote axonal myelination. Under the piezoelectric effect of this nerve scaffold, the rats with regenerative nerve exhibited a favorable recovery effect of motor and sensory function, indicating a safe and feasible method of using this SF/PVDF-HFP/MXene piezoelectric scaffold for ES provision in vivo.

Hybrid Systems of Nanofibers and Polymeric Nanoparticles for Biological Application and Delivery Systems

Nanomedicine is a new discipline resulting from the combination of nanotechnology and biomedicine. Nanomedicine has contributed to the development of new and improved treatments, diagnoses, and therapies. In this field, nanoparticles have notable importance due to their unique properties and characteristics, which are useful in different applications, including tissue engineering, biomarkers, and drug delivery systems. Electrospinning is a versatile technique used to produce fibrous mats. The high surface area of the electrospun mats makes them suitable for applications in fields using nanoparticles. Electrospun mats are used for tissue engineering, wound dressing, water-treatment filters, biosensors, nanocomposites, medical implants, protective clothing materials, cosmetics, and drug delivery systems. The combination of nanoparticles with nanofibers creates hybrid systems that acquire properties that differ from their components' characteristics. By utilizing nanoparticles and nanofibers composed of dissimilar polymers, the two synergize to improve the overall performance of electrospinning mats and nanoparticles. This review summarizes the hybrid systems of polymeric nanoparticles and polymeric nanofibers, critically analyzing how the combination improves the properties of the materials and contributes to the reduction of some disadvantages found in nanometric devices and systems.

Electrospun Nanofiber Composites for Drug Delivery: A Review on Current Progresses

A medication’s approximate release profile should be sustained in order to generate the desired therapeutic effect. The drug’s release site, duration, and rate must all be adjusted to the drug’s therapeutic aim. However, when designing drug delivery systems, this may be a considerable hurdle. Electrospinning is a promising method of creating a nanofibrous membrane since it enables drugs to be placed in the nanofiber composite and released over time. Nanofiber composites designed through electrospinning for drug release purposes are commonly constructed of simple structures. This nanofiber composite produces matrices with nanoscale fiber structure, large surface area to volume ratio, and a high porosity with small pore size. The nanofiber composite’s large surface area to volume ratio can aid with cell binding and multiplication, drug loading, and mass transfer processes. The nanofiber composite acts as a container for drugs that can be customized to a wide range of drug release kinetics. Drugs may be electrospun after being dissolved or dispersed in the polymer solution, or they can be physically or chemically bound to the nanofiber surface. The composition and internal structure of the nanofibers are crucial for medicine release patterns.

Emerging Bioactive Agent Delivery-Based Regenerative Therapies for Lower Genitourinary Tissues

Injury to lower genitourinary (GU) tissues, which may result in either infertility and/or organ dysfunctions, threatens the overall health of humans. Bioactive agent-based regenerative therapy is a promising therapeutic method. However, strategies for spatiotemporal delivery of bioactive agents with optimal stability, activity, and tunable delivery for effective sustained disease management are still in need and present challenges. In this review, we present the advancements of the pivotal components in delivery systems, including biomedical innovations, system fabrication methods, and loading strategies, which may improve the performance of delivery systems for better regenerative effects. We also review the most recent developments in the application of these technologies, and the potential for delivery-based regenerative therapies to treat lower GU injuries. Recent progress suggests that the use of advanced strategies have not only made it possible to develop better and more diverse functionalities, but also more precise, and smarter bioactive agent delivery systems for regenerative therapy. Their application in lower GU injury treatment has achieved certain effects in both patients with lower genitourinary injuries and/or in model animals. The continuous evolution of biomaterials and therapeutic agents, advances in three-dimensional printing, as well as emerging techniques all show a promising future for the treatment of lower GU-related disorders and dysfunctions.