Surface Activation Modification Of DNA Chips

DNA chips with amino groups and epoxy groups on the surface were prepared with 3-aminopropyltriethoxysilane (APTES) and 3-glycidoxypropyltrimethoxysilone (GPTMS) as the surface modifier separately by a special immersion method. The impacts of different modifiers under different process conditions and process parameters on the performance of the chip surface were studied in the preparation process.(1) Surface amino modified DNA chips were prepared using APTMS as modifying agents by immersion process via three steps:hydroxylation, acid treatment and modification. Through experimental optimization, the best modification conditions are found as follows: hydroxylation time of 2h; acid treatment time of 3h; soaking in APTES concentration of 0.6mol·L-1, soaking for Id, the temperature is 50℃. According to the XPS test results, APTES could make substrate surface contain amino groups by reacting with substrate surface. And after modification the substrate can efficiently combine with the probe seen from spotting and hybridization results.(2) Surface epoxy modified DNA chips were prepared using GPTMS as the modifier by immersion process. The chips were low substrate noise, strong signal intensity and high signal-to-noise ratio. Through the spotting test results of the substrates modified by different experimental conditions, the optimum modification conditions are:GPTMS concentration of 0.6mol·L-1, HAc concentration of 0.18mol·L-1, soaking time:24h, post-processing temperature:100℃, post-processing time:20min. The XPS detection results show the substrate surface contained epoxy groups after modification using GPTMS. The modified substrate transmittance proves the reliability of the noise and signal detection result.