Yantian Wang

A potentiometric protein sensor built with surface molecular imprinting method.

Surface molecular imprinting, as compared to molecular imprinted bulk polymers, has the advantages of higher re-occupation percentage of the reception sites, fast response, integration of sensing element and transducer, etc. In this study, a potentiometric protein sensor was developed based on the surface molecular imprinting technique. Using the self-assembled monolayers of alkanethiol with hydroxyl terminal groups as the matrix material, and target protein molecules as the template, the sensing layer was created on the surface of the gold-coated silicon chip-an electrochemical transducer. Potentiometric measurement demonstrated that the sensor could selectively detect myoglobin or hemoglobin molecules, either with or without the presence of other protein molecules in the same solution.

X-ray Linear Dichroism Microscopy of Crystalline Short Chain Alkanes and Semi-crystalline Polyethylene Thin Films

Scanning transmission x-ray microscopy (STXM) has been used to determine the two Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra of n-tetracontane (C40H82) crystallites corresponding to the a and b directions of the orthorhombic unit cell of crystalline polyethylene. The two anisotropic lateral crystalline axis a and b, i.e. and directions, respectively, can be distinguished by intensity changes in the spectral doublet near 287.5 eV. Prior NEXAFS dichroism data of PE and alkanes integrated over the and directions and only the dichroisms between the C-C chain along the c-axis and the average for the C-H bonds has been known [1]. The spectra of n-tetracontane crystals can only be explained by a “further breakdown” of the building block model [2] and interactions between individual molecules.