Silicon nanowires with high-k hafnium oxide dielectrics for sensitive detection of small nucleic acid oligomers.
Nanobiosensors based on silicon nanowire field effect transistors offer advantages of low cost, label-free detection, and potential for massive parallelization. As a result, these sensors have often been suggested as an attractive option for applications in point-of-care (POC) medical diagnostics. Unfortunately, a number of performance issues, such as gate leakage and current instability due to fluid contact, have prevented widespread adoption of the technology for routine use. High-k dielectrics, such as hafnium oxide (HfO(2)), have the known ability to address these challenges by passivating the exposed surfaces against destabilizing concerns of ion transport. With these fundamental stability issues addressed, a promising target for POC diagnostics and SiNWFETs has been small oligonucleotides, more specifically, microRNA (miRNA). MicroRNAs are small RNA oligonucleotides which bind to mRNAs, causing translational repression of proteins, gene silencing, and expressions are typically altered in several forms of cancer. In this paper, we describe a process for fabricating stable HfO(2) dielectric-based silicon nanowires for biosensing applications. Here we demonstrate sensing of single-stranded DNA analogues to their microRNA cousins using miR-10b and miR-21 as templates, both known to be upregulated in breast cancer. We characterize the effect of surface functionalization on device performance using the miR-10b DNA analogue as the target sequence and different molecular weight poly-l-lysine as the functionalization layer. By optimizing the surface functionalization and fabrication protocol, we were able to achieve <100 fM detection levels of the miR-10b DNA analogue, with a theoretical limit of detection of 1 fM. Moreover, the noncomplementary DNA target strand, based on miR-21, showed very little response, indicating a highly sensitive and highly selective biosensing platform.
Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
Brian R
BR
Dorvel
Bobby
B
Reddy
Jonghyun
J
Go
Carlos
C
Duarte Guevara
Eric
E
Salm
Muhammad Ashraful
MA
Alam
Rashid
R
Bashir
D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods; D001943:Breast Neoplasms / Q000235:genetics; D055664:Electrochemical Techniques; D005260:Female; D006195:Hafnium / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D035683:MicroRNAs / Q000032:analysis / Q000235:genetics; D036103:Nanotechnology; D053770:Nanowires / Q000737:chemistry / Q000648:ultrastructure; D009696:Nucleic Acids / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D010087:Oxides / Q000737:chemistry; D019095:Point-of-Care Systems; D012825:Silicon / Q000737:chemistry; D014173:Transistors, Electronic
C547183:MIRN10 microRNA, human; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D009696:Nucleic Acids; D010087:Oxides; C545179:hafnium oxide; D006195:Hafnium; D012825:Silicon