Shasheng Huang

A novel gene carrier based on amino-modified silica nanoparticles

Uniform-sized amino-modified silica nanoparticles have been prepared by the controlled synchronous hydrolysis of tetraethoxysilane and N-(β-amimoethyl)-γ-aminopropyltriethoxysilane in water nanodroplet of the wa-ter-in-oil microemulsion. These nanoparticles display positive charge potential at definited pH. This is due to the presence of amino groups on the surface of the nanoparticles. Nanoparticles-plasmid DNA complexes can easily form through electrostatical binding between the positive charges of the amino-modified silica nanoparticles and the negative charges of the plasmid DNA. The complexes can be also dissociated under alkaline pH or high ionic strength conditions. And enzymatic digestion of the plasmid DNA is almost inhibited by these nanoparticles complexes. A novel non-viral gene carrier based on the amino-modified silica nanoparticles is proposed under the combination of nanotechnology, biotechnology and gene engineering technology. The plasmid DNA can successfully cross various systemic barriers to COS-7 cells as well as mediate high expression of Green Fluorescence Protein (GFP) gene in cells by use of this novel gene carrier.

Au nanochannels technique and its application in immunoassay

Au nanotubules (channels) can be electrolessly plated within the pores of polycarbonate microporous filtration membranes. When an electric field was applied on the cell consisting of the membrane and Pt electrodes, the response current decreased due to a baffle effect from big molecules when the electrolyte ion and big molecules passed through the channels modified with chemical groups. Based on this principle, a nanotubules-based sensing technique has been developed. This method can be applied to the determination of human IgG.with a detection limit of 0.34 ng/mL.

The amplified fluorescence quenching of heteroatomic conjugated polymers based on the “molecular wire” effects

Tremendous interest has been evoked in the utility of the fluorescent conjugated polymers towards the creation of ultra-sensitive systems based on the molecular wire effects which can amplify the transduction events. Here, a series of new polymers —pyridine substitute poly (phenylene ethynylene)s are synthesized by Sonogashira-Hagihara coupling reaction. The impact of structure modification on the physical properties and spectral characteristics of polymers has been investigated. The quenching studies are carried out and exhibit that recognition site (pyridyle group) highly influences the quenching efficiency. The results show that polymer PI with pyridyl group entrapped in the conjugated backbone has the specific and sensitive response to Pd(II). The fluorescence quenching of P I by Pd(II) is about 65 times greater than that of model monomer.