Yang Lian-sheng

Water-soluble chitosan nanoparticles as a novel carrier system for protein delivery

High MW chitosan (CS) solutions have already been proposed as vehicles for protein delivery. The aim of the present work is to investigate the potential utility of water-soluble chitosan (WSC) as vehicles to load and deliver proteins. WSC nanoparticles (WSC NP) with various formations were prepared based on ionic gelation of WSC with pentasodium tripolyphosphate (TPP) anions. Bovine serum albumin (BSA) was used as a model protein drug incorporated into the WSC nanoparticles. Blank and BSA-loaded WSC nanoparticles were examined and determined to have a spherical shape with diameters between 35–190 nm, and zeta potential between 35–42 mV. FTIR confirmed that the tripolyphosphoric groups of TPP linked to the ammonium groups of WSC in the nanoparticles. Some factors affecting delivery properties of BSA have been investigated. Altering the concentration of BSA from 0.05 to 1 mg/mL enhanced the loading capacity of BSA but decreased loading efficiency simultaneously. Also, with the introduction of poly ethylene glycol (PEG), BSA release accelerated. Nanoparticle preparation from WSC with various deacetylation degrees (DDs) from 72.6% to 90% and MWs ranging from 3.5 to 15.8 kDa promoted loading efficiency and decreased the release rate. These results indicate that WSC nanoparticles are promising carriers for protein delivery.

Development and evaluation of a line immunoassay as a confirmatory test for human immunodeficiency virus (HIV)-1/2 infections

Serological methods are the main methods in diagnosis of human immunodeficiency virus (HIV)-1 and HIV-2 infection. The western Blot (WB) is considered as a gold standard test for the confirmation of enzyme-linked immunosorbent assay (ELISA) and/or other rapid screened reactive results samples in the diagnosis of HIV infection. However, problems of WB, particularly in regard to the significance of indeterminate results, still remain. To develop and evaluate a recombinant HIV-1/2 antigens-based line immunoassay as confirmatory assay for HIV-1 and HIV-2 infections is the objective of this study. HIV-1 envelope proteins (gp160, gp120, gp41), HIV-1 integrase protein (p31), HIV-1 gag proteins (p24, p17) and HIV-2 envelope protein (gp 36) were cloned and expressed in Escherichia coli. All recombinant HIV antigens were purified and immobilized on nitrocellulose membranes and applied in a line immunoassay, which supplement detected anti-HIV antibodies in a single strip. Specific antibodies to these antigens in human sera were revealed using an alkaline phosphatase labeled anti-human immunoglobulin G (IgG) as second antibody. Two anti-human IgG lines were used as a control for the addition of serum. Positive or negative results were determined by visual comparison of the antigen lines intensity with the two control lines. The recombinant HIV antigens-based line immunoassay identified seropositive individuals with a high degree of accuracy; none of the HIV-seropositive subjects yielded a negative result. Reactivity with these antigens, demonstrated 100% sensitivity and specificity in distinguishing seronegative from seropositive sera. This line immunoassay was much more sensitive and specific than WB. In particular, the line immunoassay allowed for a significant reduction in the number of indeterminate results and for more accurate distinction between HIV-1 and/or HIV-2 infections.