Nanogap dielectric spectroscopy for aptamer-based protein detection.
Among the various label-free methods for monitoring biomolecular interactions, capacitive sensors stand out due to their simple instrumentation and compatibility with multiplex formats. However, electrode polarization due to ion gradient formation and noise from solution conductance limited early dielectric spectroscopic measurements to high frequencies only, which in turn limited their sensitivity to biomolecular interactions, as the applied excitation signals were too fast for the charged macromolecules to respond. To minimize electrode polarization effects, capacitive sensors with 20 nm electrode separation were fabricated using silicon dioxide sacrificial layer techniques. The nanoscale separation of the capacitive electrodes in the sensor results in an enhanced overlapping of electrical double layers, and apparently a more ordered "ice-like" water structure. Such effects in turn reduce low frequency contributions from bulk sample resistance and from electrode polarization, and thus markedly enhance sensitivity toward biomolecular interactions. Using these nanogap capacitive sensors, highly sensitive, label-free aptamer-based detection of protein molecules is achieved.
Microelectronics Research Center, New Jersey Institute of Technology, Newark, New Jersey, USA.
Manu Sebastian
MS
Mannoor
Teena
T
James
Dentcho V
DV
Ivanov
Les
L
Beadling
William
W
Braunlin
D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D017097:Electric Impedance; D004566:Electrodes; D009113:Muramidase / Q000032:analysis / Q000378:metabolism; D036103:Nanotechnology / Q000379:methods*; D011506:Proteins / Q000032:analysis* / Q000378:metabolism; D013057:Spectrum Analysis; D013917:Thrombin / Q000032:analysis / Q000378:metabolism
D052157:Aptamers, Nucleotide; D011506:Proteins; D009113:Muramidase; D013917:Thrombin