Chitosan nanofibrous scaffold with graded and controlled release of ciprofloxacin and BMP-2 nanoparticles for the conception of bone regeneration.

The repair of bone defects using grafts is commonly employed in clinical practice. However, the risk of infection poses a significant concern. Tissue engineering scaffolds with antibacterial functionalities offer a better approach for bone tissue repair. In this work, firstly, two kinds of nanoparticles were prepared using chitosan to complex with ciprofloxacin and BMP-2, respectively. The ciprofloxacin complex nanoparticles improved the dissolution efficiency of ciprofloxacin achieving a potent antibacterial effect and cumulative release reached 95 % in 7 h. For BMP-2 complexed nanoparticles, the release time points can be programmed at 80 h, 100 h or 180 h by regulating the number of coating chitosan layers. Secondly, a functional scaffold was prepared by combining the two nanoparticles with chitosan nanofibers. The microscopic nanofiber structure of the scaffold with 27.28 m2/g specific surface area promotes cell adhesion, high porosity provides space for cell growth, and facilitates drug loading and release. The multifunctional scaffold exhibits programmed release function, and has obvious antibacterial effect at the initial stage of implantation, and releases BMP-2 to promote osteogenic differentiation of mesenchymal stem cells after the antibacterial effect ends. The scaffold is expected to be applied in clinical bone repair and graft infection prevention.

In situ alginate crosslinking during spray-drying of lactobacilli probiotics promotes gastrointestinal-targeted delivery.

Alginate-based formulations have shown desirable functional characteristics for probiotic encapsulation. However, current technologies used to produce these formulations are inefficient, detrimental to probiotics viability or do not produce dry, shelf-stable products. Herein, we developed a novel spray-drying technique that combines particle formation, alginate crosslinking and drying into a single step, thereby streamlining the production of encapsulated probiotics powder. Lacticaseibacillus rhamnosus GG (LGG) encapsulated in six encapsulation formulations were characterized and compared. Among the six formulations investigated, the crosslinked alginate with sucrose formulation (Ca-Alg-Suc) was found to be most promising, achieving ~109 CFU/g of surviving LGG after spray-drying and exposure to simulated gastric fluid (SGF). The Ca-Alg-Suc formulation was further evaluated with Lactiplantibacillus plantarum and Lacticaseibacillus paracasei, and similar results of high post-spray-drying and post-SGF viabilities were obtained. Successful encapsulation of different lactobacilli probiotics via the proposed spray-drying technique highlights potential of this procedure to be scaled up for commercial applications.

Valorizing okara waste into nutritionally rich polysaccharide/protein-extracts for co-encapsulation of ß-carotene and ferrous sulphate as a potential approach to tackle micronutrient malnutrition.

Colossal amounts of food waste are generated and discarded daily at the expense of financial resources and at a detriment to the environment. One such food waste, okara - a soybean by-product, is valorized in this study by upcycling it into nutritional extracts for micronutrients encapsulation. Micronutrient malnutrition, particularly in the developing world, is a major public health challenge. Herein, okara extracts were obtained through a low-cost extraction process and was subsequently developed as an encapsulant material for micronutrients ß-carotene, and ferrous sulphate encapsulation, using zein as an excipient. Spray-drying, as a scalable technique, was employed to produce various formulations which were assessed for release profiles, shelf-life, ß-carotene antioxidant activity and cell cytotoxicity. Finally, an optimized dual-micronutrient formulation displayed a sequential release with ferrous sulphate releasing in simulated gastric fluid, and ß-carotene releasing predominantly in simulated intestinal fluid. This sequential release profile favors the absorption of both the micronutrients and could potentially enhance their bioavailability.