Current issues and potential solutions for the electrospinning of major polysaccharides and proteins: A review

Recent progress in biopolymer-based electrospun nanofibers and their potential biomedical applications: A review

Tissue engineering offers an alternative approach to developing biological substitutes that restore, maintain, or enhance tissue functionality by integrating principles from medicine, biology, and engineering. In this context, biopolymer-based electrospun nanofibers have emerged as attractive platforms due to their superior physicochemical properties, including excellent biocompatibility, non-toxicity, and desirable biodegradability, compared to synthetic polymers. Considerable efforts have been dedicated to developing suitable substitutes for various biomedical applications, with electrospinning receiving considerable attention as a versatile technique for fabricating nanofibrous platforms. While the applications of biopolymer-based electrospun nanofibers in the biomedical field have been previously reviewed, recent advancements in the electrospinning technique and its specific applications in areas such as bone regeneration, wound healing, drug delivery, and protein/peptide delivery remain underexplored from a material science perspective. This work systematically highlights the effects of biopolymers and critical parameters, including polymer molecular weight, viscosity, applied voltage, flow rate, and tip-to-collector distance, on the resulting nanofiber properties. The selection criteria for different biopolymers tailored to desired biomedical applications are also discussed. Additionally, the challenges and limitations associated with biopolymer-based electrospun nanofibers, alongside future perspectives for advancing their biomedical applications, are rationally analyzed.

Optimizing solvent systems for electrospun PLGA scaffolds: effects on microstructure and mechanical properties for biomedical applications

Electrospun scaffolds fabricated from poly(lactic-co-glycolic acid) (PLGA) have garnered widespread interest in biomedical applications due to their ability to mimic the extracellular matrix (ECM) structure with a tunable degradability profile. The properties of electrospun scaffolds are meticulously tailored for specific applications through the adjustment of polymer properties, solution parameters, and processing conditions. Solvent selection is crucial, influencing polymer spinnability and scaffold topographical, physical and mechanical features. Hansen solubility theory aids in predicting suitable solvent systems. The absence of specific data prompted a solubility experiment to determine Hansen solubility parameters for PLGA. Subsequently, various solvent systems were investigated for their impact on the microstructure of electrospun PLGA scaffolds. Optimizing the electrospinning process resulted in fibrous scaffolds with consistent average fibre diameter from different solvent systems, allowing a focused examination of the solvent's isolated influence on mechanical properties. PLGA samples electrospun using hexafluoro isopropanol (HFIP) displayed lower Young's modulus and ultimate tensile strength but higher failure strains than those created using binary solvent systems composed of tetrahydrofuran (THF), dichloromethane (DCM), and dimethylformamide (DMF). This research advances the understanding and optimization of electrospun PLGA scaffolds, enhancing their potential for biomedical applications.

Encapsulation of D-limonene in Lepidium perfoliatum seed gum/PVA electrospun nanofibers: Physicochemical characterization and modeling the kinetics of release

To improve the stability of D-limonene, a protective barrier is essential to prevent degradation and maintain its integrity. Therefore, the potential of using Lepidium perfoliatum seed gum (LPSG) as a novel source for creating electrospun nanofibers for D-limonene encapsulation was investigated by varying LPSG concentrations (0.25%, 0.5%, 0.75%, and 1% w/v) and LPSG/PVA (Polyvinyl alcohol) mixing ratios (ranging from 100:0 to 0:100 v/v). Surface tension, electrical conductivity, zeta potential, and viscosity of solutions increased as LPSG concentration and its ratio in the LPSG/PVA blend increased. Uniform, smooth, and small size nanofibers were created by electrospinning a LPSG to PVA ratio of 30:70 (v/v) using LPSG concentrations of 0.5% (w/v) and 0.75% (w/v). The FTIR analysis demonstrated that D-limonene was physically trapped within the nanofibers and confirmed the compatibility of LPSG and PVA. Following its encapsulation inside LPSG/PVA nanofibers, D-limonene's thermal stability increased. The highest D-limonene encapsulation efficiency was 96.23% for 0.75% LPSG/PVA nanofibers, which was chosen to measure the D-limonene release kinetics in simulated food models. D-limonene was most readily released in distilled water with an explosive release mechanism. The mechanism of D-limonene release from LPSG/PVA electrospun nanofibers was best described by the Peppas-Sahlin model, and the release followed Fickian diffusion mechanism. The results of this study confirmed the potential of LPSG/PVA electrospun nanofibers to effectively trap D-limonene and improve its thermal stability.

Development of polysaccharide based intelligent packaging system for visually monitoring of food freshness

With the increased awareness on food freshness and food quality among consumers, the intelligent packaging films that can visually monitor the freshness of packaged foods by observing the color changes of packaging materials are gradually drawing more and more attentions. In this paper, various colorimetric indicators, types of polysaccharides as film-forming materials, production methods, freshness monitoring application, along with the future development of different intelligent packaging films are illustrated detailedly and deeply. Natural pH sensitive indicators such as anthocyanin, alizarin, curcumin, betaines and chlorophylls, as well as the gases sensitive indicators (hydrogen sulfide sensitive indicators and ethylene sensitive indicators) are the most widely used indicators for monitoring of food freshness. By incorporating different colorimetric indicators into polysaccharides (starch, chitosan, gum and cellulose derivatives) based substrates, the intelligent packaging films can be fabricated by solvent casting method, extrusion-blow molding method and electrospinning technique for monitoring of meat products, fruits, vegetables, milk products and other food products. In conclusion, intelligent packaging films with colorimetric functions are promising and feasible methods for real-time monitoring of food freshness, while stable colorimetric indicators, new film-forming methods and cheaper polysaccharide materials are still needed to develop for further commercialization.

Polysaccharide base electrospun nanofibrous scaffolds for cartilage tissue engineering: Challenges and opportunities

Polysaccharides, known as naturally abundant macromolecular materials which can be easily modified chemically, have always attracted scientists' interest due to their outstanding properties in tissue engineering. Moreover, their intrinsic similarity to cartilage ECM components, biocompatibility, and non-harsh processing conditions make polysaccharides an excellent option for cartilage tissue engineering. Imitating the natural ECM structure to form a fibrous scaffold at the nanometer scale in order to recreate the optimal environment for cartilage regeneration has always been attractive for researchers in the past few years. However, there are some challenges for polysaccharides electrospun nanofibers preparation, such as poor solubility (Alginate, cellulose, chitin), high viscosity (alginate, chitosan, and Hyaluronic acid), high surface tension, etc. Several methods are reported in the literature for facing polysaccharide electrospinning issues, such as using carrier polymers, modification of polysaccharides, and using different solvent systems. In this review, considering the importance of polysaccharide-based electrospun nanofibers in cartilage tissue engineering applications, the main achievements in the past few years, and challenges for their electrospinning process are discussed. After careful investigation of reported studies in the last few years, alginate, chitosan, hyaluronic acid, chondroitin sulfate, and cellulose were chosen as the main polysaccharide base electrospun nanofibers used for cartilage regeneration.

Emerging Multiscale Biofabrication Approaches for Bacteriotherapy

Bacteriotherapy is emerging as a strategic and effective approach to treat infections by providing putatively harmless bacteria (i.e., probiotics) as antagonists to pathogens. Proper delivery of probiotics or their metabolites (i.e., post-biotics) can facilitate their availing of biomaterial encapsulation via innovative manufacturing technologies. This review paper aims to provide the most recent biomaterial-assisted strategies proposed to treat infections or dysbiosis using bacteriotherapy. We revised the encapsulation processes across multiscale biomaterial approaches, which could be ideal for targeting different tissues and suit diverse therapeutic opportunities. Hydrogels, and specifically polysaccharides, are the focus of this review, as they have been reported to better sustain the vitality of the live cells incorporated. Specifically, the approaches used for fabricating hydrogel-based devices with increasing dimensionality (D)-namely, 0D (i.e., particles), 1D (i.e., fibers), 2D (i.e., fiber meshes), and 3D (i.e., scaffolds)-endowed with probiotics, were detailed by describing their advantages and challenges, along with a future overlook in the field. Electrospinning, electrospray, and 3D bioprinting were investigated as new biofabrication methods for probiotic encapsulation within multidimensional matrices. Finally, examples of biomaterial-based systems for cell and possibly post-biotic release were reported.