Preparation and encapsulation techniques of chitosan microsphere for enhanced bioavailability of natural antioxidants

Enhancing Encapsulation Efficiency of Chavir Essential Oil via Enzymatic Hydrolysis and Ultrasonication of Whey Protein Concentrate-Maltodextrin

This study focused on the characterization of emulsions and microparticles encapsulating Chavir essential oil (EO) by application of modified whey protein concentrate-maltodextrin (WPC-MD). Different physical, chemical, morphological, thermal, and antioxidant properties and release behavior of spray-dried microparticles were assessed. Antioxidant, solubility, emulsifying, and foaming activities of modified WPC were increased compared to those of primary material. The results indicated that the particle size distribution varied depending on the type of carriers used, with the smallest particles formed by hydrolyzed WPC (HWPC). Binary blends of modified WPC-MD led to improved particle sizes. The spray-drying yield ranged from 64.1% to 85.0%, with higher yields observed for blends of MD with sonicated WPC (UWPC). Microparticles prepared from primary WPC showed irregular and wrinkled surfaces with indentations and pores, indicating a less uniform morphology. The UWPC as a wall material led to microparticles with increased small cracks and holes on their surface. However, HWPC negatively affected the integrity of the microparticles, resulting in broken particles with irregular shapes and surface cracks, indicating poor microcapsule formation. Encapsulating EO using WPC-MD increased the thermal stability of EO significantly, enhancing the degradation temperature of EO by 2 to 2.5-fold. The application of primary WPC (alone or in combination with MD) as wall materials produced particles with the lowest antioxidant properties because the EO cannot migrate to the surface of the particles. Enzymatic hydrolysis of WPC negatively impacted microparticle integrity, potentially increasing EO release. These findings underscore the crucial role of wall materials in shaping the physical, morphological, thermal, antioxidant, and release properties of spray-dried microparticles, offering valuable insights for microencapsulation techniques.

Application of low-, and medium-molecular weight chitosan for preparation of spray-dried microparticles loaded with Ferulago angulata essential oil: Physicochemical, antioxidant, antibacterial and in-vitro release properties

The present work aimed at spray-drying encapsulation of Chavir (Ferulago angulata) essential oil (EO) using low-, and medium-molecular weight chitosan. The obtained EO was observed to be mainly composed of β-ocimene, α-pinene, and bornyl acetate with antioxidant, and antimicrobial activity. The results indicated that stable emulsions with uniform particle size distribution and encapsulation efficiencies higher than 93 % could be prepared using chitosan as feed for spray-drying. In addition, spray-drying resulted in fabricating stable microspheres with yields higher than 50 %, uniform particle size, and encapsulation efficiency exceeding 70 %. The microspheres were fairly soluble and hygroscopic, and exhibited antioxidant and bacteriostatic activities with a biphasic release pattern. FTIR characterisation confirmed successful encapsulation of EO and thermal properties of microspheres indicated enhanced stability of EO after microencapsulation. Overall, it was revealed that molecular weight of chitosan and EO:chitosan ratio affects some physicochemical properties of obtained chitosan microspheres.

Application of Biomedical Microspheres in Wound Healing

Tissue injury, one of the most common traumatic injuries in daily life, easily leads to secondary wound infections. To promote wound healing and reduce scarring, various kinds of wound dressings, such as gauze, bandages, sponges, patches, and microspheres, have been developed for wound healing. Among them, microsphere-based tissue dressings have attracted increasing attention due to the advantage of easy to fabricate, excellent physicochemical performance and superior drug release ability. In this review, we first introduced the common methods for microspheres preparation, such as emulsification-solvent method, electrospray method, microfluidic technology as well as phase separation methods. Next, we summarized the common biomaterials for the fabrication of the microspheres including natural polymers and synthetic polymers. Then, we presented the application of the various microspheres from different processing methods in wound healing and other applications. Finally, we analyzed the limitations and discussed the future development direction of microspheres in the future.