Visualization of the biofilm pH with a microscope
Source: BAM
Bacterial biofilm formation on surfaces is associated with harmful effects on human health and biofouling including microbial influenced corrosion. Particularly important for corrosion processes is the pH value in biofilms. However, most conventional techniques are not suited for minimally invasive pH measurements of living biofilms and the online in situ monitoring of pH.
Here, a fluorescent nanosensor is presented for ratiometric measurements of pH in biofilms in the range of pH 4.5–9.5 using confocal laser scanning microscopy. The nanosensor consists of biocompatible polystyrene nanoparticles that are core-stained with the pH inert dye Nile Red and surface functionalized with a pH responsive fluorescein dye. The nanosensor performance was validated by fluorometrically monitoring the time dependent changes in pH in E. coli biofilms after glucose inoculation at different temperatures. These measurements revealed a temperature-dependent decrease in pH over a 4-h period caused by the acidifying glucose metabolism of E. coli. These studies demonstrate the applicability of this nanosensor to characterize the chemical microenvironment in biofilms with very sensitive and versatile fluorescence methods
Monitoring and imaging pH in biofilms utilizing a fluorescent polymeric nanosensor
Ch. Kromer, K. Schwibbert, A. K. Gadicherla, D. Thiele, Nithiya Nirmalananthan-Budau, P. Laux, Ute Resch-Genger, A. Luch, H. R. Tschiche
published in Scientific Reports, Vol. 1, article 9823, pages 1-10, 2022
BAM division Biophotonics