Por-Si-based DNA microarray for DNA detection using IR microspectroscopy. (a) Por-Si layers are locally formed on a Si wafer substrate; (b) each spot of por-Si layer is modified with probe DNA with different base sequences; (c) the microarray is placed in buffer solution to hybridize target DNA to probe DNA; and (d) infrared microspectroscopy is used to detect hybridized target DNAs.
Single-stranded probe DNA (target DNA) immobilized on the pore surfaces. Por-Si has a number of straight pores with a diameter of approximately 30 nm. Single-stranded DNA (target DNA) is attached to the pore surface through a linker molecule.
Procedure for the formation of por-Si-based microarray. (a) Thermal oxidation of Si wafer; (b) patterning of Si oxide by photolithography; (c) anisotropic etching of Si; (d) removal of Si oxide; and (e) por-Si formation.
(a), (b) Schematic illustration and (c), (d) typical secondary-electron microscope (SEM) images of the por-Si-based microarray. (c) Top view and (b), (d) cross-sectional view of the etched parts of the microarray.
Procedure for surface modification of pore surfaces for the attachment of DNA to the pore surface. (a) The surface is irradiated with UV light from a low-pressure mercury lamp to form silicon oxides on it. (b) The oxidized surface is then reacted with 3-mercaptopropyltrimethoxysilane (MPTMS) to form a self-assembled monolayer (SAM) of MPTMS. (c) The MPTMS SAM layer has the thiol group on it. (d) The surface with the SAM layer is subsequently coupled in aqueous solution with a thiol-modified DNA to produce the DNA-modified surface.
IR spectral changes caused by UV irradiation. In the inset is shown an enlarged Si-H vibration spectrum of the irradiated surface.
(a) C-H stretching vibration and (b) bending vibration spectra of the MPTMS-adsorbed por-Si surface before and after a rinse, compared with the theoretically predicted spectra obtained through ab initio cluster calculation of a free MPTMS molecule, and an immobilized MPTMS.
IRAS spectra of the por-Si after immersion in a solution of in and subsequent rinses in .
IRAS spectra of por-Si immediately after immersion into a solution of NaCl in containing and after subsequent rinse in a solution of NaCl in for different durations, together with an IRAS spectrum of a 20-based oligonucleotide of adenine .
IRAS spectra of the por-Si immediately after immersion into a solution of NaCl in containing and after subsequent rinse in a solution of NaCl in for different durations, together with a typical IRAS spectra of a 20-based oligonucleotide of cytosine .
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