ABSTRACT
Biofilms are microbial communities composed of bacteria cells and self-produced extracellular polymeric substances and lead to antibiotic resistance, forming a great threat in the fields of medicine, food industries and so on. The formation of biofilms is a multi-stage dynamic process regulated by multiple mechanisms. Recently, researchers paid much more attention to the related research areas of biofilms, especially the detection methods of biofilms. This paper introduced the characteristics and formation process of biofilms as well as the effects of quorum sensing on biofilms development. Meanwhile, we discussed the detection methods of biofilms, especially electrochemical impedance spectroscopy (EIS) in detection of biofilms in detail. Furthermore, we reviewed and predicted that microfluidic chips based EIS served as an in-situ and online monitoring method for biofilms growth.
ABSTRACT
A highly sensitive electrochemical deoxyribonucleic acid(DNA) biosensor based on multi-walled carbon nanotubes(MWNT)/Ag-TiO_2 composite film was developed. The solution containing Ag-TiO_2-MWNT composite was casted on the carbon paste electrode surface to form a robust film, which combine the advantages of the good biocompatibility of Ag-TiO_2 naocomposite and the fine conductivity, as well as the large active surface area of carbon nanotubes. The composite could greatly improve the immobilization capacity of the probe DNA. The morphologies and electrochemistry of the nanocomposite film were investigated by scanning electron microscopy and electrochemical techniques including electrochemical impedance spectroscopy and cyclic voltammetry, respectively. DNA hybridization events were monitored by a label-free method of electrochemical impedance spectroscopy. This label-free electrochemical impedance DNA biosensor showed high sensitivity and selectivity for phosphinothricin acetyltransferase gene sequence assay. The multicomponents films also displayed a high stability during repeated regeneration and hybridization process.