A nanoelectronic enzyme-linked immunosorbent assay for detection of proteins in physiological solutions.
Semiconducting nanowires are promising ultrasensitive, label-free sensors for small molecules, DNA, proteins, and cellular function. Nanowire field-effect transistors (FETs) function by sensing the charge of a bound molecule. However, solutions of physiological ionic strength compromise the detection of specific binding events due to ionic (Debye) screening. A general solution to this limitation with the development of a hybrid nanoelectronic enzyme-linked immunosorbent assay (ne-ELISA) that combines the power of enzymatic conversion of a bound substrate with electronic detection is demonstrated. This novel configuration produces a local enzyme-mediated pH change proportional to the bound ligand concentration. It is shown that nanowire FETs configured as pH sensors can be used for the quantitative detection of interleukin-2 in physiologically buffered solution at concentrations as low as 1.6 pg mL(-1). By successfully bypassing the Debye screening inherent in physiological fluids, the ne-ELISA promises wide applicability for ligand detection in a range of relevant solutions.
Stern
Eric
E
Departments of Electrical, Biomedical, and Chemical Engineering, and Applied Physics, School of Engineering, Yale University, New Haven, CT 06511, USA.
Vacic
Aleksandar
A
Li
Chao
C
Ishikawa
Fumiaki N
FN
Zhou
Chongwu
C
Reed
Mark A
MA
Fahmy
Tarek M
TM
D004563:Electrochemistry; D004583:Electrons; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007376:Interleukin-2 / Q000032:analysis*; D053770:Nanowires / Q000737:chemistry* / Q000648:ultrastructure; D012996:Solutions
D007376:Interleukin-2; D012996:Solutions