Artificial Antibodies for Bioanalyte Detection-Sensing Viruses and Proteins

Molecular imprinting has become an increasingly popular method for the design of artificial antibodies against a variety of analytes, and especially as a method for detecting viruses and proteins. Self‐assembly of a virus on a stamp enables us to generate patterns on a polymer. Combined with mass‐sensitive transducers, the reinclusion of viruses, such as the tobacco mosaic virus (TMV), the human rhinovirus (HRV), and the parapox ovis virus (PPOV), into the patterned polymer layer can be followed directly. Recognition is favored by a geometrical fit between the analyte and the patterned layer, as well as by noncovalent interactions; the former can be observed by the highly selective enrichment of rod‐shaped TMV and globular HRV on their respective imprints, showing only negligible cross‐sensitivity. The latter is demonstrated by the selective incorporation of different HRV serotypes (HRV‐1a and HRV‐16) that have the same geometric dimensions but nonetheless are clearly distinguished from each other. Similar behavior is observed with protein molecules that are about one order of magnitude smaller than viruses, having molecular dimensions of a few nanometers. When using proteins for imprinting, the resulting materials usually preferably incorporate into their own template. Artificial antibodies generated by imprinting polymers with bioanalytes are used for selective and sensitive detection of proteins and viruses. Specific geometric‐ and chemical‐recognition interactions are monitored by the resonance‐frequency changes of a quartz‐crystal microbalance. In a powerful demonstration of this technique, two different serotypes of the human rhinovirus (HRV) with very similar molecular dimensions are clearly distinguished (see figure).