使用QCM-D研究细菌繁殖

Biolin Scientific[ Progress Together] [Application Overview] 4 Studies of bacteria using QCM-D QCM-D is an emerging tool for real-time study and detection of bacteria， as recentlyexemplified by the development of sensitive assays to detect bacterial pathogens orsimultaneous QCM-D and microscopy measurements. Introduction Bacteria are in a size range which makes it possible to imagebacterial adhesion by microscopy simultaneous with QCM-Dmeasurements. Through simultaneous imaging and recordingit can be shown how the distance and attachment strengthbetween the bacterial cell body and the surface affects theresponse from the QCM-D. [Figure 1]： Bacterial bond maturation， compared to adhesion of rigid silicananoparticles. Figure re-used from [2] with permission from the authors. Bacterium-substrate bond maturation studies [1]， [2] Bacterial adhesion can be monitored by QCM-D as interactionsbetween the bacteria and the surface are sensed via frequencychanges in the vibrating sensor. The magnitude of the QCM-Dresponse was found to be influenced by the distance at whichthe cell body was held from the sensor surface by its surfaceappendages. In this example， a "bold" bacterium， completelydevoid of surface appendages， was also investigated and therewas a clear difference in the response comparing the bold bacteriawith the ones with appendages. Combined QCM-Dand microscopy un [Figure 2]： Dissipation shifts from comparison of high (thick line) and low E. coliO157：H7 concentration. Dashed lines indicate the negative control with cell freesample. Figure reused from [3] with permission from the authors. QCM-D biosensor for pathogen detection [3] Microbial pathogens， such as E. coli O157：H7， are responsible forwater contamination， and their early detection is an importantissue. Here， polyclonal antibodies targeting E. coli O157：H7 wereimmobilized onto a QCM-D sensor surface. The immobilizationenabled real-time measurements of the presence of the pathogenin water solution. In this example， QCM-D data indicating changesin rigidity of the film was the most sensitive parameter forpathogen detection. Bacterial adhesion stage [Figure 3]： Comparison of P. aeruginosa attachment to a clean silica and a silicasurface that was pretreated by 4-nitropyridine-N-oxide. Negative frequencyshifts correspond to mass uptake. Figure re-used from [4] with permission fromthe authors. Surface modification for reduced biofilm formation [4] Bacterial group behaviors such as biofilm formation in response topopulation density are regulated by small signal molecules calledautoinducers (quorum sensing， QS). In this study， the QS inhibitor4-nitropyridine-N-oxide (4-NPO) was adsorbed to surfaces， andit was shown by QCM-D that surfaces treated in this way greatlyresisted bacterial adhesion. ( References： ) ( [1] Adam L.J. Olsson ， H enny C. van d e r M e i， Henk J. Busscher， a n d Prashant K. Sharma Influence of Cell Surface Appendages on the Bacterium Substratum I nterface Measured Real-Time Using QCM-D Langmuir， 25， 1627-1632 (2009) ) ( [2] Adam L . J. O l sson， Henny C . van d er M ei， Henk J . Busscher， a nd Prashant K.Sharma Novel Analysis of Bacterium-Substratum Bond Matura t ion Measured Using a Quartz C rystal Microbalance Lang mu ir， 2 6(13)， 111 1 3-1 1 117 (2010) ) ( [ 3] Charles Poitras， Nathalie T u fenkji A QCM-D- b ased bios e nsor for E. coli O157：H7 highlighting the relevance of the dissipation slope as a transduction signal， Biosensors and Bioelectron i cs， 24， 2137-2142 (2009) ) [4] Nune Vanoyan， Sharon L. Walker， Osnat Gillor， and Moshe HerzbergReduced Bacterial Deposition and Attachment by Quorum-Sensing Inhibitor4-Nitro-pyridine-N-oxide：The Role of Physicochemical Effects Langmuir， 26，12089-12094(2010) Biolin Scientific [Progress Together] E-mail：info@biolinscientific.combiolinscientific.com []Q-Sense AO