Can New Biosensors be Deduced from Sensing in Biology ?

Abstract

Natural recognition and transduction systems are checked in regard to their possible immediate or mediate use in biosensors. The majority of the sensors known so far base on enzymes as biological recognition part, and start transduction only after the catalytic formation of a secondary chemical signal. On the other hand in nature transduction is not catalytic but uses a conformational change for direct or indirect — after a chemical amplification cascade — modulation of a membrane permeability. The use of “ion channels” for biosensor construction would in principle be possible, however, suffer from the instability and complexity of the biological system. More promising seem to be the attempts for the development of artificial ions channels. While synthetic ionophors have already successfully been used in sensors, the corresponding application of carrier proteins is just at the beginning, however, the construction of biomimetic systems seems to be more advantageous. Antibodies as most versatile and inexpensive recognition molecules have often been used in biosensors with various transducing principles. A disadvantage is the slow kinetics of the dissociation of antigen-antibody complexes which implies problems with the regeneration of sensors. Therefore in some cases the competition of supramolecular artificial “receptors” may be more promising. The mechanism of odor and taste perception is to-day well understood, but it would not be worthwhile to transfer it to artificial sensors. Nevertheless, the implied adaption of natural receptors to demands of the molecules to be recognized could be a model for computer aided molecular conception of artificial receptors. As the natural selectivity could certainly not be attained, array arrangements could be used for partial compensation. Whenever proteins are integrated in biosensors, one should regard their instability and include into further sensor developments methods for protein stabilization.