Trends in the Design and Application of Optical Chemosensors in Pharmaceutical and Biomedical Analysis

Abstract

During the last two decades the design of devices for the sensing of pharmaceutically and biologically important compounds has acquired great interest. The miniaturization of these devices in instrumental analytical techniques allows the manipulation of small sample volumes (submicroliter). The chemical nature of the chemosensor and the nature of the molecular analyte-chemosensor interaction determine the response to be measured or detected. Some instances are the changes in the colour or fluorescence properties of the chemosensor as a consequence of the interaction with the analyte or the changes in the near-infrared electromagnetic radiation that facilitate the quality control in manufacturing of pharmaceutical compounds by near-infrared analysis (NIRA). Molecular recognition of different inorganic and organic analytes involves different mechanisms. The spectroscopic properties of the signalling subunit of the sensor may change after interaction with the analytes, or alternatively the spectroscopic properties of the chemo- or bio-sensor are modified as a consequence of the displacement of the sensor by the analytes. In such cases the sensor bound to the receptor exhibits different properties than the free sensor. In this field the rapid development of different approaches such as molecularly imprinting polymers and other cavitands (cyclodextrins and calixarenes), has led to the specific determination of biologically interesting compounds and chiral recognition processes. The evaluation of the levels of clinically interesting compounds by conventional approaches requires frequent blood sampling and therefore the possibility of using different devices for the continuous monitoring of physiological compounds is an attractive subject in which the use of fiber optical chemo- or bio-sensors is being considered with growing interest. Keywords: Fluorescent sensors, Miniaturization, Fiber optical (bio)sensors