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DNA templated nanowires of a pentynyl-modified poly2-(2-thienyl)-pyrrole undergo functionalisation via"click chemistry" and retain their 1D-nanostructure and conductive properties.

Silicon nanowire field effect transistors (NWFETs) are low noise, low power, ultrasensitive biosensors that are highly amenable to integration. However, using NWFETs to achieve direct protein detection in physiological buffers such as blood serum remains difficult due to Debye screening, nonspecific binding, and stringent functionalization requirements. In this work, we performed an indirect sandwich immunoassay in serum combined with exponential DNA amplification and pH measurement by ultrasensitive NWFET sensors. Measurements of model cytokine interleukin-2 concentrations from <20 fM to >200 pM were demonstrated, surpassing the conventional NWFET urease-based readout. Our approach paves way for future development of universal, highly sensitive, miniaturized, and integrated nanoelectronic devices that can be applied to a wide variety of analytes.

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A series of modified nucleosides based on thymidine have been prepared by Pd-catalysed cross-coupling between N-alkyl-alkynyl functionalised pyrrolyl- (py), 2-(2-thienyl)pyrrolyl- (tp) or 2,5-bis(2-thienyl)pyrrolyl (tpt) groups with 5-iodo-2'-deoxyuridine. The length of the alkyl chain linking the nucleoside and pyrrolyl-containing unit, N(CH(2))(n)C[triple bond, length as m-dash]C-nucleoside (where n = 1-3) was also varied. The compounds have been characterised by (1)H NMR, ES-MS, UV-vis, cyclic voltammetry (CV) and, in some cases, single-crystal X-ray diffraction. Cyclic voltammetry studies demonstrated that all the py-, tp- and tpt-alkynyl derivatives 1-7 can be electrochemically polymerised to form conductive materials. It was found that increasing the N-alkyl chain length in these cases resulted in only minor changes in the oxidation potential. The same behaviour was observed for the tp- and tpt-modified nucleosides 9-12; however, the py-derivative, 8, produced a poorly conducting material. DFT calculations on the one-electron oxidised cation of the modified nucleosides bearing tp or tpt showed that spin density is located on the pyrrolyl and thienyl units in all cases and that the coplanarity of adjacent rings increases upon oxidation. In contrast, in the corresponding pyrrolyl cases the spin density is distributed over the whole molecule, suggesting that polymerisation does not occur solely at the pyrrolyl-Cα position and the conjugation is interrupted.