A simple microdroplet chip consisting of silica nanochannel-assisted electrode and paper cover for highly sensitive electrochemiluminescent detection of drugs in human serum.

This paper describes a simple and miniaturized microdroplet chip (μchip) that is constructed with a silica nanochannel (SNC)-assisted electrode array and a hydrophobic paper cover (SNC&P-μchip). Vertically aligned SNCs with uniform pore size of 2-3 nm in diameter and negatively charged surface can significantly accelerate the mass transport of the positively charged tris(2,2'-bipyridyl) ruthenium (II), resulting in a remarkably enhanced electrochemiluminescence (ECL) signal. The SNC-assisted electrode array was coupled to a low cost paper cover to achieve simultaneous detection of six samples in 1 min. The feasibility and universality of the SNC&P-μchip was evaluated by detecting a series of alkaloidal drugs both in buffers and in human serum. The performance of the SNC&P-μchip was fully validated with respect to linearity (0.9999 > R > 0.9939), sensitivity (limits of detection from 1.799 nM to 11.43 nM), and accuracy (recovery rate between 94.38% and 109.12%). The facile and economic SNC&P-μchip shows promising potential for rapid drug detection in complex biofluids.