A novel substrate for in situ synthesis of oligonucleotide: plasma-treated polypropylene microporous membrane

Polypropylene microporous membrane was treated with plasma in a mixture of nitrogen and hydrogen (1:2 in volume). Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and ultra-violet (UV) spectra demonstrated the success of amino functional groups grafting. The density of polar amino groups on the membrane surface is approximately 0.5 μmol/cm2, which is much higher than that of amino functional groups on modified glass slides. The as-treated membranes were successively applied to the in situ synthesis of oligonucleotides and an average coupling yield of more than 98% was achieved. These modified microporous membranes open novel prospects for the in situ synthesis of DNA microarrays.