Papers by Author: Lei Ren

Abstract: Extremely small-sized superparamagnetic magnetite nanoparticles of 3Cit). The resulting Cit-coated magnetite nanoparticles exhibited long-term colloidal stability in aqueous media without any surface modification. Regarding the magnetic properties, the nanoparticles were superparamagnetic at room temperature, and might be the potential candidate for MRI contrast agents.

Abstract: Novel hybrid biomaterial of gelatin-siloxane nanoparticles (GS NPs), with positive surface potential and lower cytotoxicity, was synthesized through a 2-step sol-gel process. The pDNA-GS NPs complex was formulated with high encapsulation efficiency, and exhibited and efficient transfection in vitro. We thus envision that the GS NPs material could serve as non-viral gene vectors for gene therapy.

Abstract: The near-infrared (NIR) sensitive Au-Au2S nanoparticles (NPs) have shown many advantages as potential drug delivery systems. To further investigate biological safety of Au-Au2S NPs, cytotoxicity was estimated by calcein AM/EthD-1 fluorescence staining and the lactate dehydrogenase (LDH) release. The effects of NPs on apoptosis of CHL cells were determined by flow cytometry with Annexin V-FITC/PI double staining. It is evident that the Au-Au2S NPs are non-cytotoxic below IC50 dosage.

Abstract: We successfully synthesized near infrared (NIR) sensitive Au(shell)-Au2S(core) nanoparticles, where Au2S dielectric core was encapsulated by a thin gold shell. The cytotoxicity in vitro and biodistribution in vivo of Au-Au2S nanoparticles was studied by using NIH3T3 cells and KM mice, respectively. The quantitative analysis of Au in each tissue of mice was done by using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Au-Au2S nanoparticles (< 300 μg/ml) showed good biocompatibility. Au-Au2S nanoparticles were preferentially taken up by the liver and spleen, and ultimately eliminated mostly in the feces.

Abstract: Ca2+-containing porous gelatin-siloxane hybrids were prepared using sol-gel process, post-gelation soaking, and freeze-drying. The porosity and pore size of the hybrids could be well controlled by the freezing temperature and the pH value of the soaking solution. The pore characteristics were related to the structure change during the soaking treatment. A bone-like apatite layer was able to form in the Ca2+-containing porous gelatin-siloxane hybrids upon soaking in a stimulated body fluid. The porous gelatin-siloxane hybrids could release gentamicin sulfate which is an antibiotic drug in bone chemotherapy. Thus, those hybrid materials are proposed to find application as novel bioactive and biodegradable scaffolds in bone tissue engineering.

Abstract: An asymmetric polysulfone membrane with reactive group of –OH was obtained by hydrolyzing the chloromethylated polysulfone membrane, and the albumin molecules were immobilized into the membrane with a crosslinking reagent of 1,4-butanediol diglycidyl ether. The albumin-fixed membrane was used to remove lipophilic toxins, bilirubin, from the bilirubin-albumin solution. The experiment results showed that the transfer rate of bilirubin was clearly enhanced after fixing albumin into the hydroxylated polysulfone membranes. The clearance of bilirubin was 49.3%. In addition, the effect of membrane thickness on the removal of bilirubin is discussed.

Abstract: Chitosan-DNA nanoparticles were synthesized from the complexation of chitosan solution and the plasmid pCD-GFP encoding green fluorescent protein through a coacervation process. The nanoparticles formed were of diameter inferior to 100 nm. The transfection efficacy of chitosan-DNA nanoparticles in MGC803 cells was higher than in SMMC-7721 cells, whereas the plasmid GFP was not expressed in MG63 cells.