AFM studies on DNA covalently immobilized on mica modified by APTES-GA

The immobilization of DNA on self-assembled layers of 3-aminopropyltrimethoxysilane (APTES) and glutaraldehyde(GA) on mica wafers by chemical coupling has been studied by using atomic force microscopy (AFM). The DNAused for our investigation is amplified by PCR and primers were labeled by -NH₂ at their 5' terminal. The surfaces were analyzed with X-ray photoelectron spectroscopy (XPS) and AFM. The results from XPS and AFM show that APTES-GA modified mica can be formed and the flatness of mica is adapted to AFM images. We found that DNA can be readily immobilized on mica. The covalent coupling between the aldehyde-terminated membrane and the both H₂N-groups in double strands DNA results in the immobilization of the DNA straightly.