Conclusions In the present study, we propose and validate by opti

Conclusions In the present study, we propose and validate by optical measurements a new method to achieve the in situ synthesis of tailored oligonucleotide sequences on porous silicon supports suitable for label-free optical biosensing. In particular, we demonstrate that,

differently from aqueous ammonia, the use of dry ammonia in methanol allows the effective deprotection of nucleobases without harming the structural integrity of the porous silicon matrix, thus opening the way for the direct growing of mixed-sequence ONs on optically active PSi supports using exclusively inexpensive standard phosphoramidites. A 19-mer FK228 in vivo mixed-sequence 5′-GATTGATGTGGTTGATTTT-3′ has been synthesized in mesoporous PSi microcavities, resulting in a medium-yield process, mainly due to the average pore size (about 20 nm). PSi photonic devices with pore dimensions greater than that value, but always compatible with high optical quality response in the visible-near-infrared, therefore between 50 and 100 nm, will be considered in the next experiments,

in order to maximize yield synthesis. Moreover, more stable PSi supports could also be considered, such as those produced by thermal acetylation, which maintains pore size and makes it very stable from the chemical point of view [18]. Acknowledgements This work has been partially supported by the national project PON Oncology. References 1. Heller MJ: DNA microarray technology: devices, this website systems, and applications. Annu Rev Biomed Eng 2002, 4:129–153. 10.1146/annurev.bioeng.4.020702.15343812117754CrossRef 2. Wang J, Rivas G, Cai X, Palecek M, Nielsen P, Shiraishi H, Dontha N, Luo D, Parrado C, Chicharro M, Flair MN: DNA electrochemical Cediranib (AZD2171) biosensors for environmental

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