Papers by Author: Hu Lin Jiang

Abstract: Novel, biodegradable poly(ester amine)s (PEAs) were synthesized using hydrophobic polycaprolactone diacrylate (PCLDA) and highly cationic polyethylenimine (PEI). This novel gene carrier can form stable DNA complexes with particle sizes around 200 nm, and showing excellent transfection efficiency and relatively low cytotoxicity compared with PEI 25K. Effect of hydrophobicity on transfection efficiency and cytotoxicity was profound and was relatively important parameter for the success of gene delivery.

Abstract: Polypropylenimine (PPI) dendrimers have been used by many researchers as gene delivery carriers due to their high functionality. Glucose as a kind of carbohydrate is biocompatible and hydrophilic. In this study, we synthesized glucosylated PPI (G-PPI) dendrimers to reduce cytotoxicity. Glucose substitution of G-PPI dendrimers was determined by the sulfuric acid micromethod. The G-PPI dendrimer was complexed with plasmid DNA in various N/P ratios, and the complex was characterized. G-PPI dendrimers showed good DNA binding ability and high protection of DNA from nuclease attack. The G-PPI dendrimer had low cytotoxicity compared to PPI dendrimer by cytotoxicity assay. Also, transfection efficiency was influenced by glucosylation degree and the transfection efficiency for the G-PPI-5 was slightly higher than that of PPI dendrimer in HeLa cell line.

Abstract: The aim of this study is to prepare mucoadhesive chitosan microspheres for protein drug to deliver to intestine through oral administration. The thiolated Eudragit was synthesized by reaction between L-cysteine hydrochloride and Eudragit® L-100. About 8 mol-% of cysteine was introduced to the Eudragit-cysteine conjugate. The conjugate was used to coat bovine serum albumin (BSA)-loaded chitosan microspheres. The average particle sizes of BSA-loaded thiolated Eudragit-coated chitsoan microspheres (TECMs) were 4.06±0.74 .m and the uniform sizedistribution was shown. The in vitro release of BSA from BSA-loaded TECMs was pH-dependent. Our results indicated that thiolated Eudragit might be a good candidate as a coating material for oral delivery of protein drug owing to mucoadhesive and pH-sensitive properties.

Abstract: Thiolated polymers have been studied by many researchers because of the mucoadhesive properties of thiol group. Alginate is a natural and biocompatible polymer that has been widely used in drug delivery. In this study, thiolated chitosan microspheres (TCMs) were prepared by ionic gelation process with tripolyphosphate and then, the bovine growth hormone (BGH) was loaded as a model drug. Finally, the BGH-loaded TCMs (BTCMs) were coated with alginate to improve the stability in gastrointestinal (GI) track. The alginate-coated BTCMs (ABTCMs) were observed as spherical shapes. The average particle sizes of ABTCMs were 6.97±0.55 -m and the sizedistribution was shown uniformly. Release of BGH from ABTCMs was decreased by coating with alginate and increased rapidly with the change in medium pH from 1.2 to 7.4. Results indicate that the ABTCMs have a potential as a drug carrier for oral drug delivery.

Abstract: The objective of this study is to develop a new type of cationic nanoparticles for the intracellular drug delivery to breast cancer. Poly(ester amine) (PEA) based on polyethylenimine and polycaprolactone was synthesized to make cationic PEA nanoparticles for all-trans retinoic acid (RA). In the 1H-NMR study, the proton signals of RA appeared in the spectrum of RA-loaded PEA nanoparticles in CDCL3, whereas they disappeared in D2O, suggesting that hydrophobic inner-core with hydrophilic outer-shell formed in water. RA release was faster at lower drug content and RA was released over a period of 20 days. RA-loaded PEA nanoparticles showed enhanced cytotoxicity compared with RA itself, whereas nanoparticles of PEA themselves did not show it. These results indicated that the cationic PEA provided an efficient intracellular delivery of RA.

Abstract: Vectors are vital aspect of gene delivery system which decides the success of gene therapy. Efficient transfection with minimum or no toxicity, are two principal aims of any gene delivery system. In this our study, we rationally developed biodegradable water soluble poly(ßamino ester) (PAE) based on spermine (SPR) and poly (ethylene glycol) (PEG), by Michael-type addition reaction and further studied for its potential as a gene carrier. Confirmation of synthesized PAE was done by proton NMR spectroscopy. In gel retardation assay, the PAEs have shown good DNA binding ability over wide range of polyplexes. The addition of PEG over SPR resulted in a novel PAE with higher degree of safety and transfection efficiency as compared with polyethylenimine 25K (PEI) when studied in 293T human kidney carcinoma cells.