Xiaohe Karen Xu

Learn More
We report a biosensor based on organophosphorus hydrolase (OPH) multilayer modified microcantilever (MCL) for detection of organophosphorus compounds (OPs). The assay is based on substrate-dependent bending of the OPH functionalized MCLs. The cantilever bending amplitude at equilibrium was a function of the concentration of paraoxon with the dynamic range(More)
Traditional real-time polymerase chain reaction (PCR) requires a purified DNA sample for PCR amplification and detection. This requires PCR tests be conducted in clean laboratories, and limits its applications for field tests. This work developed a method that can carry out DNA purification, amplification and detection in a single PCR tube. The(More)
Microcantilevers (MCLs) hold a position as a cost-effective and highly sensitive sensor platform for medical diagnostics, environmental analysis and fast throughput analysis. MCLs are unique in that adsorption of analytes on the microcantilever (MCL) surface changes the surface characteristics of the MCL and results in bending of the MCL. Surface stress due(More)
Femtomolar concentrations of hydrogen fluoride, a decomposition component of nerve agents, were detected using a SiO(2) microcantilever. The microcantilever underwent bending due to the reaction of HF with SiO(2). The microcantilever deflection increased as the concentration of HF increased. Other acids, such as HCl, had no effect on the deflection of the(More)
A potential novel binding assay based on binding-driven micromechanical motion is described. A membrane preparation containing 5-HT(3AS) receptors was used to modify a microcantilever. The modified microcantilever was found to bend on application of the naturally occurring agonist (5-hydroxytryptamine, which is also called serotonin) or the antagonist(More)
A potential binding assay based on binding-driven micromechanical motion is described. Acetylcholine binding protein (AChBP) was used to modify a microcantilever. The modified microcantilever was found to bend on application of the naturally occurring agonist (acetylcholine) or the antagonist (nicotine and d-tubocurarine). Control experiments show that(More)
Nanowires from deposition of pyromellitic diimide (PMDI) from the gas phase and their unique excitation-wavelength-dependent photoluminescence were demonstrated. The luminescence peaks of the PMDI nanowires red-shifted as the excitation wavelength increased. The relationship between the luminescence peak and the excitation wavelength is nearly linear in a(More)
Trace amounts of Hg2+ are detected by using a microcantilever coated with gold. The microcantilever undergoes bending due to accumulation of Hg2+ on the gold surface. It is found that a concentration of 10(-11) M Hg2+ can be detected using this technology. Other cations, such as K+, Na+, Pb2+, Zn2+, Ni2, Cd2+, Cu2+, and Ca2+ have little or no effect on the(More)
We report a novel enzyme-based microcantilever sensor by using layer-by-layer nanoassembly modification. A glucose oxidase (GOx) functionalized microcantilever underwent bending when it was exposed to glucose solutions. The magnitudes of bending were proportional to the concentrations of glucose. The cantilever bending was specific toward glucose, but not(More)