Application Of Zinc Oxide Nano Functional Materials And Its Biosensor Detection

Zinc oxide nanomaterials with the specific nanostructure and performances have received increasing applications as photocatalysts, transducers, and optical devices. Especially, Zn O nanomaterials with tunable fluorescence are cheap and nontoxic quantum dots(QDs) that possess the potential of replacing the toxic semiconductor QDs(i.e., Cd Se and Cd Te) to be applied in the optical fields. In this paper, on the one hand, the functionalized Zn O nanocomposites with dramatically enhanced tunable fluorescence have been prepared and applied to the biological imaging. On the other hand, microarrays based on the Zn O substrate combined with immune recognition and nucleic acid hybridization reaction have been established for the detection of biomarkers of disease and cancer early diagnosis. The main content includes:(1) Zn O quantum dots(QDs) were synthesized and further modified with hydrophobic hexadecyltrimethoxysilane(HDS) and then hydrophilic aminopropyltriethoxysilane(APS)bilayers, resulting in the functionalized Zn O@HDS@APS nanocomposites with tunable fluorescence from blue to green yellow. Systematic investigations verify that the resulting Zn O@HDS@APS could display extremely high stability in aqueous media and unexpectedly,dramatically-enhanced fluorescence intensities, which are about 10-fold higher than those of bare Zn O QDs. The feasibility of the as-prepared Zn O nanocomposites for blood, cell, and tissue imaging was preliminarily demonstrated.(2) A glass slide was first patterned with hydrophobic HDS and then microspotted with hydrophilic Zn O nanoparticles in APS matrix. Theresulting HDS–Zn O–APS microarray could present the capability of suppressing the undesirable “coffee-ring” effects through its lotus-like“self-cleaning” hydrophobic pattern. The immunoglobulin Ig G antigen has been fixed on the microspot and applied for the “Sandwich” method fluorescence detection of Ig G antigen in serum samples. More importantly, the introduction of Zn O nanoparticles could endow the testing microspots with substrate-enhanced fluorescence leading to signal-amplification microarray fluorometry for the sensitive and rapid Ig G detection of mutil-samples.(3) The HDS-Zn O-APS microarray has been fixed by the single stranded DNA(ss DNA)capture probe and combined with the peroxidase activity of the DNA enzyme, to establish a colorimentric detection methods for free mi RNA in multi-blood samples at the same time. The ss DNA capture probes with hemin-binding sequences and the complementary sequences of mi RNA have been designed here, which were covalently anchored on theamine-derivatizedZn O-APS testing dots. After mi RNA target hybridization, exonuclease I was introduced to specifically digest the ss DNA probes unhybridized. Furthermore, hemin was added to form the hemin-G-quadruplex DNAzyme to achieve the ATP-enhanced catalytic amplification of visible coloration signals. Such a high throughput, selective and sensitive microarray-based colorimetric method could be tailored for quantifying short-chain mi RNAs of low levels in blood.