title: Screening-limited response of nanobiosensors.
abstract: Despite tremendous potential of highly sensitive electronic detection of biomolecules by nanoscale biosensors for genomics and proteomic applications, many aspects of experimentally observed sensor response (S) are difficult to understand within isolated theoretical frameworks of kinetic response or electrolyte screening. In this paper, we combine analytic solutions of Poisson-Boltzmann and diffusion-capture equations to show that the electrostatic screening within an ionic environment limits the response of nanobiosensor such that S(t) approximately c1(ln(rho0) - ln(I0)/2 + ln(t)/ D F + c2[pH]) + c3 where c i are geometry-dependent constants, rho0 is the concentration of target molecules, I0 the salt concentration, and D F the fractal dimension of sensor surface. Our analysis provides a coherent theoretical interpretation of a wide variety of puzzling experimental data that have so far defied intuitive explanation.
authors.affiliation: School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA. pnair@purdue.edu
authors.forename: Pradeep R
authors.initials: PR
authors.lastname: Nair
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Alam
mesh_terms: D016477:Artifacts; D001704:Biopolymers / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008956:Models, Chemical; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001704:Biopolymers