Development of quartz crystal microbalance (QCM) based biosensor for determination of lactons by molecular imprinting methods

While high living organisms use sounds and words to communicate with each other, bacteria provide this function with some communication molecules. These communication molecules are expressed as "Quorum Sensing" (QS) or chemicals produced by the environment sensing system and used by bacteria to communicate. N-acyl-homoserine-lactones (AHL) that are the main signaling molecules of Gram-negative bacteria, may express the pathogenic factors, and the Quorum Sensing system may play an important role in the identification of the being virus. AHLs are produced at low concentrations that are difficult to detect with general techniques. In this study, molecularly imprinted polymeric membranes, which are specific to lactone with 6-carbons (C6-HSL) were prepared on the QCM chips and molecularly imprinted QCM chips were utilized to detect N-Hexanoyl-L-homoserine lactone (C6-HSL) with high sensitivity from the aqueous medium. After pre-oganization of C6-HSL (template molecule) and functional monomer (acrylamide) with the secondary forces to form molecular imprinting structure, C6-HSL imprinted polymeric membrans in the presence of 2-hydroxyethyl methacrylate (HEMA) as monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinker, and azobisisobutyronitrile (AIBN) as initiator were polymerized with the aid of UV-initiated polymerization. Characterization of the synthesized polymers were come true by AFM, SEM, contact angle and FTIR-ATR spectrophotometer analyzes. The optimal pre-organization between the C6-HSL-acrylamide (DMF as solvent) was determined at pH 7.0. The maximum C6-HSL adsorption on the C6-HSL imprinted QCM chip surface was observed at 1000 ng/mL concentration, pH 7.0. Moreover, the GC-MS results correlated with the results of our studies, and they confirmed the sensitivity of synthesized the polymers toward C6-HSL.