No abstract

Many applications in proteomics and lab-on-chip analysis require methods that guide proteins to assemble at surfaces with high spatial and temporal control. Electrical inputs are particularly convenient to control, and there has been considerable effort to discover simple and generic mechanisms that allow electrical inputs to trigger protein assembly on-demand. Here, we report the electroaddressing of a protein to a patterned surface by coupling two generic electroaddressing mechanisms. First, we electrodeposit the stimuli-responsive film-forming aminopolysaccharide chitosan to form a hydrogel matrix at the electrode surface. After deposition, the matrix is chemically functionalized with alkyne groups. Second, we ''electro-click' an azide-tagged protein to the functionalized matrix using electrical signals to trigger conjugation by Huisgen 1,3-dipolar cycloadditions. Specifically, a cathodic potential is applied to the matrix-coated electrode to reduce Cu(II) to Cu(I) which is required for the click reaction. Using fluorescently-labeled bovine serum albumin as our model, we demonstrate that protein conjugation can be controlled spatially and temporally. We anticipate that the coupling of polysaccharide electrodeposition and electro-click chemistry will provide a simple and generic approach to electroaddress proteins within compatible hydrogel matrices.

Defective Pt/Bi4NbO8Br composites were fabricated via a facile in situ chemical reduction method. The synergistic effect of Pt and oxygen vacancies endows the hybrid photocatalysts with enhanced efficiency for versatile organic pollutant removal.

No abstract

Water-soluble N-carboxymethylthioureidochitosan (CMTC) was synthesized by the reaction between chitosan (CTS) and ammonium thiocyanate and chloroacetic acid in a hydrochloric acid aqueous solution. The modified product was confirmed by Fourier transform infrared (FTIR) spectrometry, X-ray diffractometry (XRD) and thermal analysis. The results showed that new functional groups had been linked to amino groups of CTS molecules, and the product was more amorphous than CTS. The dispersion stability of CMTC was examined with a sedimentation test of 1 wt.% kaolin suspension in test tubes, under different concentrations and different pH. The results indicated that CMTC may be applicable for use as a novel stabilizer in neutral solution in which the concentration of CMTC is 0.5% or 1%.