Papers by Author: Yong Liu

Abstract: In this paper, the properties of chitosan nanoparticles and bovine serum albumin-loaded chitosan nanoparticles prepared with sodium tripolyphosphate at different pH values were discussed. Interactions in chitosan nanoparticles and bovine serum albumin-loaded chitosan nanoparticles were analyzed by Fourier transform infrared spectroscopy and differential scanning calorimetry. The results indicated that there were more complicated interactions in chitosan nanoparticles prepared at different pH values. When the pH values were lower or higher than isoelectric point value of target protein (bovine serum albumin), the big different interactions occurred in chitosan nanoparticles. These differences also would result in different releasing properties.

Abstract: In this paper, the properties of chitosan (CS) nanoparticles (CS NPs) and Bovine Serum Albumin (BSA) loaded chitosan nanoparticles (BSA-loaded CS NPs) prepared with sodium tripolyphosphate (TPP) at different pH values were discussed. In addition, BSA encapsulation efficiency, zeta potentials and size of CS NPs and BSA-loaded CS NPs were characterized. The results indicated that sizes of CS NPs presented “V” change along with increase of pH values, while the size of BSA-loaded CS NPs showed “U” shape change. BSA encapsulation efficiency reached the biggest value when the pH value was 5.5. Zeta potentials of CS NPs and BSA-loaded CS NPs kept going down when the pH values were increasing, and positive potential of CS-loaded BSA CS NPs became higher than that of CS NPS when the pH value was more than 5.5. BSA-loaded CS NPs prepared at pH 5.5 exhibited regular and close to spherical in shape under transmission electron microscopy (TEM) sight.

Abstract: This work aims to prepare and characterize one kind of nitric oxide (NO)-releasing conjugation of quaternary ammonium salt to chitosan, as well as to evaluate the anti-bacterial properties of diazeniumdiolates and the changes in NO release properties. The newly synthesized diazeniumdiolates are obtained from glycidyl-trimethyl-ammonium chloride (GTMAC)-bearing chitosan derivatives (HTCC) with different molecular weights (280 and 670 KDa) and are used as NO donor species. An HTCC with high molecular weight (670 KDa) exhibits higher storage capacity for NO (up to 357.70 nmol NO/mg) than one with a low molecular weight (280 kDa). The NO release durations (7 h) observed for the HTCC diazeniumliolates with higher molecular weight (670 kDa) was slightly higher than that of HTCC diazeniumliolates with lower molecular weight (280 kDa). By determining the inhibition zone diameter, HTCC-NO with lower molecular weight (280 kDa) showed significantly higher inhibition capabilities against E. coli than HTCC, crude chitosan, and water control.

Abstract: These new synthesized diazeniumdiolates obtained from D-gluconic acid-bearing chitosan derivatives (SBC) with different molecular weight (280 kDa and 880 KDa) and D-gluconic acid-bearing O-carboxymethyl chitosan derivatives (880 KDa) (SBCS) were used as the NO donor species. Compared with SBC with much higher molecular weight (880 KDa), the SBC with the lower molecular weight (280 kDa) exhibited a high storage capacity for NO (up to 408 nmol NO/mg), greatly increasing the “payload” of released NO with the molecular weight of SBC decreasing. The NO release durations (0.326 h) observed for secondary amine on the SBC with the lower molecular weight (280 kDa) were slightly higher than that of SBC diazeniumliolates with the higher molecular weight (880 kDa), which was only 0.294h. The release duration of SBCS-NO adducts (0.381h) was obviously longer than that of SBC-NO adducts, when they have the same molecular weight (880 kDa).