In-situ signal amplification of microneedles in a transistor for allergy molecular detection.

The rapid and accurate detection of histamine is of great significance for the early diagnosis and precise treatment of allergic diseases. Traditional histamine detection usually is more invasive and limited for the detection of allergic reactions in local areas. In this work, microneedles (MNs) enable of in-situ transdermal detection are employed as the extended gate of the thin-film transistor (TFT). By combing the in-situ signal amplification of TFT, the MN-TFT is integrated for the high-specific and high-sensitive detection of subcutaneous histamine. This approach retains the semi-invasive, real-time detection benefits of MNs while amplifying signals and enhancing sensor sensitivity through the transistor. In addition, the recognition layer on the MN sensing electrode is constructed by the electro-polymerization of molecular imprinted polymers (MIPs), which contains specific cavities designed to bind histamine molecules through hydrogen bonding to ensure the stability and specificity. The results show that the MN-TFT demonstrates good detection sensitivity (18.1 μA/decade) and specificity with the limit of detection (LoD) improved by a factor of ∼10. Further, the subcutaneous detection results demonstrate that the MN-TFT exhibits excellent specificity for histamine in mice, enabling precise monitoring of histamine fluctuations over time in vivo.