Preparation and characterization of an electrodeposited calcium phosphate coating associated with a calcium alginate matrix

Recent progress in preparation and agricultural application of microcapsules

Recent advances in life science technology have prompted the need to develop microcapsule delivery systems that can encapsulate many different functional or active materials such as drugs, peptides, and live cells, etc. The encapsulation technology is now commonly used in medicine, agriculture, food, and other many fields. The application of biodegradable microcapsule systems can not only effectively prevent the degradation of core materials in the body or the biological environment, but also improve the bioavailability, control the release and prolong the halftime or storage of core active materials. Various wall materials, preparation methods, encapsulation processes, and release mechanisms are covered in this review, as well as several main factors including pH values, temperatures, particle sizes, and additives, which can strongly influence the encapsulation efficiency, the strength, and release of microcapsules. The improvement of coating materials, preparation techniques, and challenges are also highlighted, as well as application prospects.

Electrical signals triggered controllable formation of calcium-alginate film for wound treatment

Wound dressings play important roles in the management of wounds, and calcium cross-linked alginate (Ca²⁺-Alg) is a commonly used hydrogel that is adapted for wound treatment. However, conventional methods for fabricating Ca²⁺-Alg hydrogels can be tedious and difficult to control because of the rapid Ca²⁺-induced gelation of alginate. In this study, An electrodeposition method was used to rapidly and controllably fabricate Ca²⁺-Alg films for wound treatment. Several measures of film growth (e.g., thickness and mass) are shown to linearly correlate to the imposed charge transfer at the electrode. Similarly, this charge transfer was also observed to control important physicochemical wound healing properties such as water uptake and retention capacity. Furthermore, a wound healing animal test was performed to evaluate the performance of this electro-fabricated calcium alginate film for wound treatment. This in vivo study demonstrated that wounds dressed with an electro-fabricated Ca²⁺-Alg film closed faster than that of untreated wounds. Further, the new dermis tissue that formed was composed of reorganized and stratified epithelial layer, with fully developed connective tissue, hair follicle, sebaceous glands as well as aligned collagen. Therefore, our study indicates that this electrofabrication method for the rapid and controlled preparation of alginate film could provide exciting opportunities for wound treatment. More broadly, this study demonstrates the potential of electrochemistry for the fabrication of high performance polymeric materials. Here we report a rapid and controllable fabrication of free-standing alginate films by coupling anodic electrodeposition with subsequent peeling of deposited materials for wound dressing.

Perfusion electrodeposition of calcium phosphate on additive manufactured titanium scaffolds for bone engineering

A perfusion electrodeposition (P-ELD) system was reported to functionalize additive manufactured Ti6Al4V scaffolds with a calcium phosphate (CaP) coating in a controlled and reproducible manner. The effects and interactions of four main process parameters - current density (I), deposition time (t), flow rate (f) and process temperature (T) - on the properties of the CaP coating were investigated. The results showed a direct relation between the parameters and the deposited CaP mass, with a significant effect for t (P=0.001) and t-f interaction (P=0.019). Computational fluid dynamic analysis showed a relatively low electrolyte velocity within the struts and a high velocity in the open areas within the P-ELD chamber, which were not influenced by a change in f. This is beneficial for promoting a controlled CaP deposition and hydrogen gas removal. Optimization studies showed that a minimum t of 6 h was needed to obtain complete coating of the scaffold regardless of I, and the thickness was increased by increasing I and t. Energy-dispersive X-ray and X-ray diffraction analysis confirmed the deposition of highly crystalline synthetic carbonated hydroxyapatite under all conditions (Ca/P ratio=1.41). High cell viability and cell-material interactions were demonstrated by in vitro culture of human periosteum derived cells on coated scaffolds. This study showed that P-ELD provides a technological tool to functionalize complex scaffold structures with a biocompatible CaP layer that has controlled and reproducible physicochemical properties suitable for bone engineering.