Clay Nanoparticle-Supported Single-Molecule Fluorescence Spectroelectrochemistry

Here we report that clay nanoparticles allow formation of a modified transparent electrode, spontaneous adsorption of fluorescent redox molecules on the clay layer, and thus the subsequent observation of single-molecule fluorescence spectroelectrochemistry. We can trace single-molecule fluorescence spectroelectrochemistry by probing the fluorescence intensity change of individually immobilized single redox molecules modulated via cyclic voltammetric potential scanning. This work opens a new approach to explore interfacial electron transfer mechanisms of redox reactions

Entrapping Enzyme in a Functionalized Nanoporous Support

The enzyme organophosphorus hydrolase (OPH) was spontaneously entrapped in carboxylethyl- or aminopropyl-functionalized mesoporous silica with rigid, uniform open-pore geometry (30 nm). This approach yielded larger amounts of protein loading and much higher specific activity of the enzyme when compared to the unfunctionalized mesoporous silica and normal porous silica with the same pore size. When OPH was incubated with the functionalized mesoporous silica, protein molecules were sequestered in or excluded from the porous material, depending on electrostatic interaction with the charged functional groups. OPH entrapped in the organically functionalized nanopores showed an exceptional high immobilization efficiency of more than 200% and enhanced stability far exceeding that of the free enzyme in solution. The combination of high protein loading, high immobilization efficiency and stability is attributed to the large and uniform pore structure, and to the optimum environment introduced by the functional groups

Synergetic Effects of Nanoporous Support and Urea on Enzyme Activity

We report synergetic effects of functionalized mesoporous silica (FMS) and urea to promote favorable protein conformational changes. The specific activity of glucose isomerase (GI) entrapped in FMS in the presence of urea was approximately double that of GI in solution in the absence of urea. Rather than losing all activity in a denaturing solution of 8.0 M urea, the specific activity of GI entrapped in FMS remained higher than the highest specific activity of GI free in solution

Ratiometric Electrochemical Determination of Ascorbic Acid Using a Copper Nanoparticle@Resin Nanosphere (CuNPs@RNS) Modified Glassy Carbon Electrode (GCE) by Differential Pulse Voltammetry (DPV)

Ascorbic acid (AA) determination is of high importance in the diagnosis and treatment of diseases. Herein, we report a new ratiometric electrochemical sensor for ascorbic acid using a glassy carbon electrode (GCE) modified with a copper nanoparticle@resin nanosphere nanocomposite (CuNPs@RNS). The ratiometric strategy was established by immobilizing an internal reference (thionine) on the modified electrode using cyclic voltammetry (CV). The performance of the modified electrodes as well as the newly established ratiometric strategy was explored. The sensing platform had good electrocatalytic ability, reproducibility, and stability. In addition, the ratiometric strategy significantly improved the performance of electrochemical sensing with a wide linear range (0.0837 to 15.5 μM) and a low detection limit of 0.0279 μM under the optimal conditions. The original ratiometric electrochemical sensor was successfully applied to monitor ascorbic acid in tablets and urine. These results showed that the sensor provides a new strategy and broad prospects for biomolecular sensing with reliability and high sensitivity.</p

Local Release of Highly Loaded Antibodies from Functionalized Nanoporous Support for Cancer Immunotherapy

Local Release of Highly Loaded Antibodies from Functionalized Nanoporous Support for Cancer Immunotherap