Real-Time and Label-Free Detection of the Prostate-Specific Antigen in Human Serum by a Polycrystalline Silicon Nanowire Field-Effect Transistor Biosensor

Abstract

In this research, we used a polycrystalline silicon nanowire field-effect transistor (poly-Si NWFET) as a biosensor that employs the sidewall spacer technique instead of an expensive electron beam lithography method. When compared with commercial semiconductor processes, the sidewall spacer technique has the advantages of simplicity and low cost. In this study, we employed a novel poly-Si NWFET device for real-time, label-free, and ultrahigh-sensitivity detection of prostate-specific antigen (PSA) in human serum. Since serum proteome is very complex containing high levels of salts and other interfering compounds, we hereby developed a standard operating procedure for real-sample pretreatment to keep a proper pH value and ionic strength of the desalted serum and also utilized Tween 20 to serve as the passivation agent by surface modification on the NWFET to reduce nonspecific binding for medical diagnostic applications. We first modified 3-aminopropyltriethoxysilane on the surface of a poly-Si nanowire device followed by glutaraldehyde functionalization, and the PSA antibodies were immobilized on the aldehyde terminal. While PSA was prepared in the buffers to maintain an appropriate pH value and ionic strength, the results indicated that the sensor could detect trace PSA at less than 5 fg/mL in a microfluidic channel. The novel poly-Si NWFET is developed as a diagnostic platform for monitoring prostate cancer and predicting the risk of early biochemical relapse.

Recent Trends in Field-Effect Transistors-Based Immunosensors

“…It is evident that a great diversity of disease biomarkers can be detected through immunoFET devices, opening new paths for early-stage diagnosis of serious diseases such as cancer. For instance, prostate specific antigen (PSA), a prostate cancer biomarker, was ultrasensitively detected by using immunoFET devices based on different nanomaterials such as silicon nanowires (SiNW) [47,48], graphene [49], molybdenum disulfide (MoS 2 ) [50,51], etc. The lowest detection limit of PSA was achieved by a FET device based on SiNW (1 fg·mL −1 ) [47].…”

“…For example, Huang et al developed a novel SiNW-FET biosensor for the detection of PSA biomarker in human serum [48]. The SiNW were fabricated by the polysilicon sidewall spacer technique, which is cheaper than the electron beam lithography.…”

Diagnosis of prostate cancer via nanotechnological approach

“…The captured PSA alters the current that runs through the CNT giving rise to detection. [147][148][149][150][151][152][153][154][155][156][157][158][159] Electrochemiluminescence assays took advantage of this in conjugation with the nature of titanium nanotubes to achieve a low detection limit of 1 fg/mL. 160 The most popular nanomaterial is gold either as nanoparticle or as a nanopore.…”

“…Compared to CNT, polysilicon nanowires demonstrated outstanding sensitivity of ~5 fg/mL of limit of detection. 149 A similar device, microgapped interdigitated enzymatic assay, achieves even higher sensitivity with a 0.9 fg/mL limit of detection. 155 Electrical sensing devices seem to be the most popular sensing method.…”

Perspectives in Glycomics and Lectin Engineering

“…nm from the surface, but for analysis of protein levels in serum, serum has to be desalted prior detection (66).…”