Journal: Microorganisms

Article Title: Bacterial Adhesion on Soft Surfaces: The Dual Role of Substrate Stiffness and Bacterial Growth Stage

doi: 10.3390/microorganisms13030637

Figure Lengend Snippet: Experimental evaluation and setup. ( A ) Example force–distance curve. The inlet shows an enlargement of the dashed area. The adhesion force is extracted from the lowest force relative to the baseline. Young’s modulus is calculated from the slope of the curve. The maximum indentation force was 100 nN. ( B ) The Hertz model when a solid sphere with a radius R indents into a sample with Young’s modulus E and Poisson’s ratio v . ( C ) Sample preparation: The sample holder consists of a magnetic bar to immobilize the holder on the AFM scanner, a glass plate at the bottom, and the sample holder’s confinement (i). The glass is plasma-treated (ii) for 45 s. Agarose gel is heated up to liquefaction and then transferred onto the sample holder (iii) until it is completely filled (iv). While the gel is still liquid, a glass coverslip is placed onto the sample holder while avoiding the entrapment of air (v). The sample is allowed to gelify and cool down for 30 min. Before measurement, the coverslip is removed horizontally (v, vi). The sample is placed onto the atomic force microscope, and the measurement liquid is injected (vii). After 15 min of relaxation time, the measurement begins (viii).

Article Snippet: By means of a Nanoscope ® V controller (Veeco, Plainview, NY, USA) atomic force microscope with a Multimode 8 scanner (Bruker, Billerica, MA, USA) [ ], force distance curves were measured on the pure agarose gels using probes with a spherical SiO 2 tip (3.5 μm diameter, 0.2 N/m force constant, CP-CONT-SiO, nanoandmore GmbH, Wetzlar, Germany).

Techniques: Sample Prep, Clinical Proteomics, Agarose Gel Electrophoresis, Microscopy, Injection

Journal: Microorganisms

Article Title: Bacterial Adhesion on Soft Surfaces: The Dual Role of Substrate Stiffness and Bacterial Growth Stage

doi: 10.3390/microorganisms13030637

Figure Lengend Snippet: Adhesion properties of C. okenii and E. coli on agarose gels of varying concentrations. The optical microscope, built onto the atomic force microscope stage, allowed for the visualization of the bacterial cells on the cantilevers, as shown in ( A ) for C. okenii and ( B ) for E. coli . The presence and viability of the cells on the cantilever were further confirmed by bringing the cantilevers in contact with agarose pads: cells from the cantilever then grew on the agarose plates (insets, with a scale bar of 10 μm), confirming their presence on the cantilever tips. In ( C , D ), the inner 50% of the measured values for the force of adhesion to the LMP agarose gel, sorted in ascending order, is represented by a colored area containing the median as a horizontal line. In addition, the average is shown as a point and the standard deviation as an error bar. Interestingly, as the LMP agarose concentration was increased, a substantial increase for the C. okenii bacterial cells ( C ) and a slight rise in the adhesion force for the E. coli bacterial cells ( D ) were observed. The statistical test (two-sample t -test) revealed a significant change in C. okenii ’s adhesion to the 1.5% versus the 3.1% agarose concentration ( p -value < 0.01), while for E. coli , this difference was not significant.

Article Snippet: By means of a Nanoscope ® V controller (Veeco, Plainview, NY, USA) atomic force microscope with a Multimode 8 scanner (Bruker, Billerica, MA, USA) [ ], force distance curves were measured on the pure agarose gels using probes with a spherical SiO 2 tip (3.5 μm diameter, 0.2 N/m force constant, CP-CONT-SiO, nanoandmore GmbH, Wetzlar, Germany).

Techniques: Microscopy, Agarose Gel Electrophoresis, Standard Deviation, Concentration Assay