title: General strategy for biodetection in high ionic strength solutions using transistor-based nanoelectronic sensors.
abstract: Transistor-based nanoelectronic sensors are capable of label-free real-time chemical and biological detection with high sensitivity and spatial resolution, although the short Debye screening length in high ionic strength solutions has made difficult applications relevant to physiological conditions. Here, we describe a new and general strategy to overcome this challenge for field-effect transistor (FET) sensors that involves incorporating a porous and biomolecule permeable polymer layer on the FET sensor. This polymer layer increases the effective screening length in the region immediately adjacent to the device surface and thereby enables detection of biomolecules in high ionic strength solutions in real-time. Studies of silicon nanowire field-effect transistors with additional polyethylene glycol (PEG) modification show that prostate specific antigen (PSA) can be readily detected in solutions with phosphate buffer (PB) concentrations as high as 150 mM, while similar devices without PEG modification only exhibit detectable signals for concentrations ≤10 mM. Concentration-dependent measurements exhibited real-time detection of PSA with a sensitivity of at least 10 nM in 100 mM PB with linear response up to the highest (1000 nM) PSA concentrations tested. The current work represents an important step toward general application of transistor-based nanoelectronic detectors for biochemical sensing in physiological environments and is expected to open up exciting opportunities for in vitro and in vivo biological sensing relevant to basic biology research through medicine.
authors: Department of Chemistry and Chemical Biology and ‡School of Engineering and Applied Science, Harvard University , Cambridge, Massachusetts 02138, United States.
authors: Ning
authors: N
authors: Gao
authors: Wei
authors: W
authors: Zhou
authors: Xiaocheng
authors: X
authors: Jiang
authors: Guosong
authors: G
authors: Hong
authors: Tian-Ming
authors: TM
authors: Fu
authors: Charles M
authors: CM
authors: Lieber
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D001826:Body Fluids / Q000737:chemistry*; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007477:Ions; D011092:Polyethylene Glycols / Q000737:chemistry*; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014173:Transistors, Electronic
chemical_list: D007477:Ions; D011092:Polyethylene Glycols; D017430:Prostate-Specific Antigen
keywords: Debye length; Semiconductor nanowires; bioelectronics; field-effect-transistor; polyethylene glycol; polymer-modified