silicon and gamma-glycidoxypropyltrimethoxysilane

A novel strategy for sensitive detection of biomarkers using horseradish peroxidase (HRP)-functionalized silica nanoparticles as the label is presented. The enzyme-functionalized silica nanoparticles were fabricated by coimmobilization of HRP and alpha-fetoprotein antibody (anti-AFP, the secondary antibody, Ab2), a model protein, onto the surface of SiO(2) nanoparticles using gamma-glycidoxypropyltrimethoxysilane (GPMS) as the linkage. Through "sandwiched" immunoreaction, the enzyme-functionalized silica nanoparticle labels were brought close to the surface of gold substrates, as confirmed by the scanning electron microscopy (SEM) images. Enhanced detection sensitivity was achieved where the large surface area of SiO(2) nanoparticle carriers increased the amount of HRP bound per sandwiched immunoreaction. The electrochemical and chemiluminescence measurement showed 29.5- and 61-fold increases in detection signals, respectively, in comparison with the traditional sandwich immunoassay. The improved particle synthesis using a "seed-particle growth" route yielded particles of narrow size distribution, which allowed consistent loading of HRP and anti-AFP on each microsphere and ensured subsequent immunosensing possessed high sensitivity and reproducibility. This strategy was successfully demonstrated as a simple, cost-effective, specific, and potent method to detect AFP in practical samples.

Topics: alpha-Fetoproteins; Animals; Antibodies, Immobilized; Biocatalysis; Biomarkers; Biosensing Techniques; Cattle; Electrochemistry; Gold; Horseradish Peroxidase; Humans; Hydrogen Peroxide; Immunoassay; Luminescence; Luminol; Nanoparticles; Oxidation-Reduction; Phenothiazines; Sensitivity and Specificity; Silanes; Silicon; Silicon Dioxide; Staining and Labeling

The embryotoxic and teratogenic potential of gamma- glycidoxypropyltrimethoxysilane ( GPTS ) was evaluated in rats. Pregnant Sprague-Dawley rats were administered 0, 50, 500, or 1,000 mg/kg/day of GPTS by gavage on days 6 through 15 of gestation. No treatment related signs of toxicity, behavioral alterations or mortalities were observed in any of the pregnant animals. There was no evidence of adverse effects in mean maternal body weight, liver weight or food consumption of the treated females. The number of implantation sites, number of live fetuses per litter, the mean litter size, the sex ratio, the fetal body weight or the crown-rump length were not affected by treatment. The incidence of resorptions among the total fetal population was not altered by the administration of GPTS to pregnant rats, indicating that the test material is not embryolethal in rats at the tested dose levels. Few scattered incidences of fetal alterations in the external, soft tissue or skeletal examinations were seen both among treated and untreated litters, however, no single alteration was observed in treated litters at an incidence which was significantly different from the control. In conclusion GPTS was not embryotoxic or teratogenic in rats at dose levels up to 1000 mg/kg/day.

Topics: Abnormalities, Drug-Induced; Animals; Body Weight; Bone and Bones; Female; Male; Pregnancy; Rats; Rats, Inbred Strains; Silanes; Silicon

The subchronic toxicity (28 days) of orally administered gamma-Glycidoxypropyltrimethoxysilane (GPTS) was studied in laboratory rats. The test material was administered daily for four weeks to groups of 10 male and 10 female Sprague-Dawley rats by gavage at dose levels of 0, 40, 400, and 1,000 mg/kg. Mortality, behavioral reactions, growth and food consumption were observed and measured along with hematology, blood biochemistry, absolute and relative organ weights. No overt signs of toxicity or behavioral abnormalities were observed in any of the test animals during the course of the study. There were no treatment related mortalities and no significant differences were observed in mean body weight, food consumption, absolute or relative organ weights of control and treated rats. Also, there were no meaningful differences in hematology, urinalysis or clinical blood chemistry values between control and treated animals. Gross and histopathologic examinations of organs or tissues from both control and GPTS treated animals did not reveal any treatment related changes. These results suggest that it is unlikely that serious injury would result from the ingestion of GPTS in amounts normally encountered incidental to its industrial use.

Topics: Animals; Body Weight; Fasting; Female; Male; Organ Size; Rats; Rats, Inbred Strains; Sex Factors; Silanes; Silicon; Time Factors