Design and Analytical Performances of a Diclofenac Biosensor for Water Resources Monitoring.

Because the broadly consumed pain killer diclofenac (DCF) is a recognized pollutant, monitoring of its concentration is routinely performed in surface waters. As a valuable alternative to chromatographic and immunochemical assays, we developed a piezoelectric immunosensor to quantify DCF, first in buffer (PBS) and then in river water samples. A sensing layer comprising DCF was built up on the surface of silica-coated quartz sensors using a robust coupling chemistry. Binding of a highly affine monoclonal anti-DCF antibody was monitored in real time by quartz crystal microbalance with dissipation (QCM-D) measurements from which were determined a dissociation constant KD of 0.24 nM and an acoustic antibody surface coverage of 1120 ng/cm2 at saturation. On the other hand, an optical antibody surface coverage of 260 ng/cm2 was determined by combined nanoplasmonic sensing measurement, giving a hydration percentage of 75% for the antibody monolayer. DCF assay was further set up following a competitive format for which binding of antibody to the sensing layer is inhibited by DCF in solution. The piezoelectric sensor response expressed as frequency shift ΔF was inversely related to the concentration of DCF with a dynamic range of 15-46 nM and a limit of detection (LoD) of 9.5 nM (2.8 µg/L) in PBS. This piezoelectric immunosensor was eventually applied to the assay of DCF in surface water samples taken at three different locations in the Seine and Marne rivers. The calculated concentration of DCF in these samples was in good agreement with official data published by the French center of water analysis eaufrance.

Strategies for Antimicrobial Peptides Immobilization on Surfaces to Prevent Biofilm Growth on Biomedical Devices.

Nosocomial and medical device-induced biofilm infections affect millions of lives and urgently require innovative preventive approaches. These pathologies have led to the development of numerous antimicrobial strategies, an emergent topic involving both natural and synthetic routes, among which some are currently under testing for clinical approval and use. Antimicrobial peptides (AMPs) are ideal candidates for this fight. Therefore, the strategies involving surface functionalization with AMPs to prevent bacterial attachment/biofilms formation have experienced a tremendous development over the last decade. In this review, we describe the different mechanisms of action by which AMPs prevent bacterial adhesion and/or biofilm formation to better address their potential as anti-infective agents. We additionally analyze AMP immobilization techniques on a variety of materials, with a focus on biomedical applications. Furthermore, we summarize the advances made to date regarding the immobilization strategies of AMPs on various surfaces and their ability to prevent the adhesion of various microorganisms. Progress toward the clinical approval of AMPs in antibiotherapy is also reviewed.