REPUBLIC OF SERBIA

MINISTRY OF DEFENCE

www.mod.gov.rs

MINISTRY OF DEFENCE

Material Resources Sector

Defensive Technologies Department

Military Technical Institute

www.vti.mod.gov.rs

Detection of target substances using affinity-based MEMS/NEMS sensors: a problem of selectivity

Ivana jokić

IHTM – Institute of Microelectronic Technologies and Single Crystals, University of Belgrade, Serbia, ijokic@nanosys.ihtm.bg.ac.rs

katarina radulović

IHTM – Institute of Microelectronic Technologies and Single Crystals, University of Belgrade, Serbia, kacar@nanosys.ihtm.bg.ac.rs

dana vasiljević-radović

IHTM – Institute of Microelectronic Technologies and Single Crystals, University of Belgrade, Serbia, dana@nanosys.ihtm.bg.ac.rs

Abstract: Affinity-based micro/nanosensors intended for detection of various chemical or biological agents in a liquid or gaseous environment have a great potential for both civilian and military applications. Selective detection of a target substance is based on highly specific binding of its particles to the functionalized surface of the sensing element. However, samples taken from the environment often contain substances other than the target, which can also bind with a certain affinity to the same functionalizing layer or binding sites, thus affecting the sensor's response. In this paper we analyze the influence of limited selectivity of a sensor on its time response. The results show that binding of a non-target substance can cause a significant change in both the equilibrium value and the rate of the sensor's response. The presented analysis enables improvement of accuracy of determination of the target substance concentration in detection methods based on time domain measurements of the sensor's output signal. It is also useful for development of methods for simultaneous detection of multiple substances.

Key words: Micro/nanoelectromechanical sensor, chemical agent, biological agent, sensor selectivity.