Along with the development of DNA microarrays, chemical surface modifications and DNA attachment strategies have played an important role with the goal to fabricate a sensitive biochip. Using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and confocal scanning fluorescence microscopy, we investigated how the surface properties and topography of (3-mercaptopropyl)trimethoxysilane (MPTS)-coated mica influenced the immobilization of 5 '-thiolated oligonucleotides. AFM, XPS and TOF-SIMS results showed that there were "island-like" structures, with a near monolayer thick, formed on the mica incubated with 53.8 mM MPTS. At high MPTS concentrations (107.6 mM and 5.38 M) the island structures disappeared. Data su...[ Read more ]

Along with the development of DNA microarrays, chemical surface modifications and DNA attachment strategies have played an important role with the goal to fabricate a sensitive biochip. Using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and confocal scanning fluorescence microscopy, we investigated how the surface properties and topography of (3-mercaptopropyl)trimethoxysilane (MPTS)-coated mica influenced the immobilization of 5 '-thiolated oligonucleotides. AFM, XPS and TOF-SIMS results showed that there were "island-like" structures, with a near monolayer thick, formed on the mica incubated with 53.8 mM MPTS. At high MPTS concentrations (107.6 mM and 5.38 M) the island structures disappeared. Data suggested that at high MPTS concentrations, multilayer of MPTS was formed which resulted in the exposure of silanol group, a poor substrate for immobilization of oligonucleotides. Results from the fluorescent scanner was consistent with our inference in which the immobilization of 5'-thiol modified oligonucleotide was maximal on surface treated with 53.8 mM MPTS solution. The coverage was ~5 times higher than the coverage on mica incubated with 5.38 M MPTS.

Certain Traditional Chinese Medicinal plants (TCM) are very toxic but difficult to be identified. While there are some TCM species acted as adulterants of the precious or the authentic ones due to their similar appearances. DNA Microarrays were introduced to identify those TCM species through their genotypes instead of phenotypes. Compared to the traditional method, this method was faster and the result was more accurate, and rather economical.