A Label‐Free Si‐BioFET With Linearly Assembled Gold Nanoparticles for the Detection of miR‐141
Taufhik Hossain Tonmoy, Diana Isabel Sandoval Bojórquez, Tu Anh Le, Nirbhika Nandakumar, Gyusang Yi, Ahmed Alsadig, Željko Janićijević, Sayantan Ghosh, Swagato Sarkar, Rabiul Islam, Artur Erbe, Caroline Murawski, Andreas Fery, Larysa BarabanABSTRACT
Sensitivity of field‐effect transistor biosensors (BioFETs) for nucleic acid detection is often limited by weak electrostatic control and low probe density at the sensing interface. Here, we present a BioFET platform with improved sensitivity based on lightly p‐doped Schottky‐barrier silicon nanobelt transistors, exhibiting reproducible ambipolar behavior in a back‐gated configuration. These devices are encapsulated with an Al 2 O 3 /ZrO 2 nanolaminate to prevent device performance degradation and facilitate stable biofunctionalization. Dry‐state measurements demonstrate selective detection of prostate cancer biomarker, miR‐141, after immobilization of complementary capture DNA, achieving detection down to the ≈100 pM range, and discrimination against the non‐complementary sequence, miR‐155. To enhance sensitivity, template‐assisted self‐assembly of gold nanoparticles (AuNPs) is used to form ordered linear structures directly on the sensing region. The supracolloidal assembly of AuNPs at the sensing interface tunes the receptor spacing and orientation and amplifies the influence of target hybridization on transistor response. Compared to planar devices, the hybrid AuNP‐BioFET exhibits improved signal modulation while preserving the label‐free detection mechanism. This approach bridges scalable top‐down semiconductor technology and bottom‐up self‐assembled nanostructures, providing an innovative pathway for developing biosensing platforms with high sensitivity and multiplexing capabilities for detecting nucleic acids.