title: Phage as a molecular recognition element in biosensors immobilized by physical adsorption.
abstract: Biosensors based on landscape phages immobilized by physical adsorption on the surface of a quartz crystal microbalance was used for detection of beta-galactosidase from Escherichia coli. The sensor had a detection limit of a few nanomoles and a response time of a approximately 100 s over the range of 0.003-210 nM. The binding dose-response curve had a typical sigmoid shape and the signal was saturated at the beta-galactosidase concentration of about 200 nM. A marked selectivity for beta-galactosidase over BSA was observed in mixed solutions even when the concentration of BSA exceeded the concentration of beta-galactosidase by a factor of approximately 2000. The apparent value of the dissociation constant (K(d)) of the interaction of free phage with beta-galactosidase (9.1+/-0.9 pM) was smaller compared with the one calculated for the bound phage (1.7+/-0.5 nM). The binding was specific with three binding sites needed to bind a single molecule of beta-galactosidase. The K(d) obtained from the enzyme-linked immunosorbent assay (ELISA) for the phage and the monoclonal anti-beta-galactosidase antibodies were 21+/-2 and 26+/-2 nM, respectively. Although the method of physical adsorption is simpler and more economical in comparison with Langmuir-Blodgett and molecular assembling methods the performances of the sensors made by these technologies compare well. This work provides evidence that phage can be used as a recognition element in biosensors using physical adsorption method for immobilization of phage on the sensor surface.
authors.affiliation: Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, AL 36849, USA.
authors.forename: Viswaprakash
authors.initials: V
authors.lastname: Nanduri
authors.forename: Iryna B
authors.initials: IB
authors.lastname: Sorokulova
authors.forename: Alexandre M
authors.initials: AM
authors.lastname: Samoylov
authors.forename: Aleksandr L
authors.initials: AL
authors.lastname: Simonian
authors.forename: Valery A
authors.initials: VA
authors.lastname: Petrenko
authors.forename: Vitaly
authors.initials: V
authors.lastname: Vodyanoy
mesh_terms: D000327:Adsorption; D001435:Bacteriophages / Q000187:drug effects* / Q000502:physiology*; D001681:Biological Assay / Q000295:instrumentation / Q000379:methods; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D001616:beta-Galactosidase / Q000032:analysis* / Q000494:pharmacology*
chemical_list: D001616:beta-Galactosidase