Production and in vitro analysis of catechin incorporated electrospun gelatin/ poly (lactic acid) microfibers for wound dressing applications

Nowadays, herbal materials are applied extensively in fibrous structures for application as a wound dressing. In this study, catechin (Cat) as the green tea extract with antibacterial characteristics has been loaded in gelatin (Gel)/poly (lactic acid) (PLA) fibrous structure by double-nozzle electrospinning technique. For this, PLA-Cat from one nozzle and Gel-Cat solution from another were injected, and fabricated Gel/PLA, Gel/PLA-Cat, Gel-Cat/PLA, and Gel-Cat/PLA-Cat hybrid fibers were gathered onto a rotating collector. In order to verify the application of these scaffolds in bio applications, the morphological, chemical, wettability property, and biological features of fibers were analyzed using SEM, contact angle analysis, antibacterial, and cell attachment tests. The viscosity of spinning solutions increased with the addition of Cat to them that resulted in an increase of fibers diameter. Fourier transform infrared spectroscopy highlighted the presence of PLA, Gel, and Cat in the final structure. The results exhibited that the presence of Cat improved the antibacterial activity. Furthermore, cell attachment studies with L929 fibroblast cells demonstrated that incorporation of catchin increased the cell viability without any toxicity.

Non-Toxic Crosslinking of Electrospun Gelatin Nanofibers for Tissue Engineering and Biomedicine—A Review

Electrospinning can be used to prepare nanofiber mats from diverse polymers, polymer blends, or polymers doped with other materials. Amongst this broad range of usable materials, biopolymers play an important role in biotechnological, biomedical, and other applications. However, several of them are water-soluble, necessitating a crosslinking step after electrospinning. While crosslinking with glutaraldehyde or other toxic chemicals is regularly reported in the literature, here, we concentrate on methods applying non-toxic or low-toxic chemicals, and enzymatic as well as physical methods. Making gelatin nanofibers non-water soluble by electrospinning them from a blend with non-water soluble polymers is another method described here. These possibilities are described together with the resulting physical properties, such as swelling behavior, mechanical strength, nanofiber morphology, or cell growth and proliferation on the crosslinked nanofiber mats. For most of these non-toxic crosslinking methods, the degree of crosslinking was found to be lower than for crosslinking with glutaraldehyde and other common toxic chemicals.

ELECTROSPUN GELATIN NANOFIBROUS SCAFFOLDS – APPLICATIONS IN TISSUE ENGINEERING

Electrospinning is highly used technique in the tissue engineering field, particularly in biomedical application [1]. The constricted concepts of this process are based on generate nonwoven nanofibers. The method involves high voltage electricity which is applied to the liquid solution and a collector, which lets the solution force out from a nozzle forming a jet. The jet formed fibers under influence of electrostatic forces concentrated and deposited these on the collector. Main objective of this study was to fabricate gelatin scaffolds with micro/nano-scale for successful wound dressing. Gelatin can mimic the chemical composition, physical structure and structure of the native skin extracellular matrix (ECM). However, the first and main principle in this study is the optimization of parameters of the electrospinning process. The used parameters have a crucial role in obtaining suitable fibers for further cell seeding and cell growth in vitro. With the use of series of various biocompatible polymers and solvents, solutions were tested in various electrospinning settings in order to produce microscale fibers. The scaffolds were analysed with scanning electron microscope images for fiber diameter measurement.

A novel 3D in vitro model of the human gut microbiota

Clinical trials and animal studies on the gut microbiota are often limited by the difficult access to the gut, restricted possibility of in vivo monitoring, and ethical issues. An easily accessible and monitorable in vitro model of the gut microbiota represents a valid tool for a wider comprehension of the mechanisms by which microbes interact with the host and with each other. Herein, we present a novel and reliable system for culturing the human gut microbiota in vitro. An electrospun gelatin structure was biofabricated as scaffold for microbial growth. The efficiency of this structure in supporting microbial proliferation and biofilm formation was initially assessed for five microbes commonly inhabiting the human gut. The human fecal microbiota was then cultured on the scaffolds and microbial biofilms monitored by confocal laser and scanning electron microscopy and quantified over time. Metagenomic analyses and Real-Time qPCRs were performed to evaluate the stability of the cultured microbiota in terms of qualitative and quantitative composition. Our results reveal the three-dimensionality of the scaffold-adhered microbial consortia that maintain the bacterial biodiversity and richness found in the original sample. These findings demonstrate the validity of the developed electrospun gelatin-based system for in vitro culturing the human gut microbiota.

Cross-Linking Optimization for Electrospun Gelatin: Challenge of Preserving Fiber Topography

Opportunely arranged micro/nano-scaled fibers represent an extremely attractive architecture for tissue engineering, as they offer an intrinsically porous structure, a high available surface, and an ideal microtopography for guiding cell migration. When fibers are made with naturally occurring polymers, matrices that closely mimic the architecture of the native extra-cellular matrix and offer specific chemical cues can be obtained. Along this track, electrospinning of collagen or gelatin is a typical and effective combination to easily prepare fibrous scaffolds with excellent properties in terms of biocompatibility and biomimicry, but an appropriate cross-linking strategy is required. Many common protocols involve the use of swelling solvents and can result in significant impairment of fibrous morphology and porosity. As a consequence, the efforts for processing gelatin into a fiber network can be vain, as a film-like morphology will be eventually presented to cells. However, this appears to be a frequently overlooked aspect. Here, the effect on fiber morphology of common cross-linking protocols was analyzed, and different strategies to improve the final morphology were evaluated (including alternative solvents, cross-linker concentration, mechanical constraint, and evaporation conditions). Finally, an optimized, fiber-preserving protocol based on carbodiimide (EDC) chemistry was defined.

Fabrication of Multifunctional Nano Gelatin/Zinc Oxide Composite Fibers

According to health studies, reinforcing gelatin is necessary in order to obtain the multifunctional material. In this study, nano zinc oxide (ZnO; at concentrations of 0.5%, 1% and 1.5%) was doped with gelatin and the solution was electrospun under specific conditions to obtain multifunctional gelatin/ZnO nanofibers. The morphology of the nanofibers was studied by field emission scanning electron microscope (FESEM), and energy-dispersive X-ray spectrometry (EDX) analysis indicated the presence of nano Zn on the surface of gelatin fibers. On the contrary, elemental mapping analysis proved the distribution of nano material along the nano gelatin fibers. The results show that the produced nano gelatin/ZnO composite increases the ultraviolet (UV) blocking of fabric significantly. It is also observed that electrospun gelatin/ZnO nanofibers have excellent bactericidal property against both Bacillus cereus (Gram-positive) and Escherichia coli (Gram-negative) bacteria.