Bacterial exopolysaccharides (EPSs) are an essential group of compounds secreted by bacteria. These versatile EPSs are utilized individually or in combination with different materials for a broad range of biomedical field functions. The various applications can be explained by the vast number of derivatives with useful properties that can be controlled. This review offers insight on the current research trend of nine commonly used EPSs, their biosynthesis pathways, their characteristics, and the biomedical applications of these relevant bioproducts.

Transfersome, a lipid-based nanovesicle, can be a suitable tool to improve the delivery of valuable growth factors. Through transfersome technology, growth factors and active compounds can be transferred transdermally without the need for invasive delivery procedures. In this study, we evaluated the impact of freeze-thaw cycles on transfersome characteristics, particularly particle size, polydispersity, and encapsulation efficiency. Transfersome particles were prepared from dipalmitoylphosphatidylcholine (DPPC) and Tween 80 with a 97.5:2.5 w/w% using thin film hydration at a temperature of 45° – 50°C. Then, the transfersome suspension was subjected to repeated freeze-thaw for 1 minute of freezing and 3 minutes of thawing. The protein release from all transfersome samples were evaluated using Bradford assay, while the particle size and polydispersity were determined with a dynamic scattering analyzer. It was found that freeze-thaw increased encapsulation efficiency, particle size, and polydispersity of transfersomes up to 81.63±0.00%, 180.70±0.87 nm, and 0.369±0.02, respectively, from those without freeze-thaw steps (73.35±0.03%, 144.93±0.21 nm and 0.202±0.02). Moreover, freeze-thawed transfersomes exhibited a release of up to 52.80% of loaded protein within 78 hours, in contrast to 37.48% in non-freeze-thawed transfersomes. This study shows that an additional freeze-thaw step is a promising method to improve the properties of transfersome particles, especially encapsulation efficiency and sustained protein release.