Journal: bioRxiv

Article Title: Sticky Situations: Bacterial Attachment Deciphered by Interferometry of Silicon Microstructures

doi: 10.1101/793125

Figure Lengend Snippet: Different microtopologies promote varying degrees of wetting, in turn promoting differences in bacterial adhesion amongst strains. (A) Contact angle values (left panel) of MB measured after 200 s on oxidized (OX) and amine-functionalized (AMINE) pores, pillars, and planar Si substrates suggest that the buffer does not completely infiltrate the pore topologies, as illustrated (right panel). MB positions partially within the microtopologies, forming small vapor pockets in pore structures, characteristic of a Cassie-Baxter wetting regime. (B) PRISM assays of E. coli WT, E. coli K-12, and S. epidermidis adhesion to OX Si pores and Si pillars over time (n = 3). Measurements were collected every 2 minutes, but error bars are placed every 10 minutes for visual clarity. (C) False-colored SEM images of bacterial cells within the microstructured pores (left) and pillars (right) reveal attachment behavior to the oxidized surfaces for each of the different strains. Scale bars represents 2 μm. (D) Summary of the Δ2nL (%) values for each E. coli WT, E. coli K-12, and S. epidermidis (abbreviated SE) after 120 min of accumulation onto oxidized pores and pillars (n = 3).

Article Snippet: As preliminary tests, the PRISM responses of three non-pathogenic bacteria strains, namely the laboratory mutant Escherichia coli ( E. coli ) K-12, clinically isolated E. coli (ATCC 25922, termed as WT), and Staphylococcus epidermidis ( S. epidermidis ATCC 14990), were observed over time, with Δ2nL (%) corresponding to the accumulation of cells in the topologies ( ).

Techniques:

Journal: bioRxiv

Article Title: Sticky Situations: Bacterial Attachment Deciphered by Interferometry of Silicon Microstructures

doi: 10.1101/793125

Figure Lengend Snippet: Motility is an underlying factor leading to bacterial adhesion within the microstructures. (A) PRISM of E. coli with a cheZ deletion causing excessive tumbling, E. coli without flagella, and E. coli with deleted chemotaxis receptors exhibit differences in adhesion behavior to oxidized (OX) pore and pillar substrates. Ryu flagellar staining reveals the presence or absence of flagella on the strains in optical microscope images. Scale bars represents 1 μm. (B) Summary of final Δ2nL (%) values reached after 120 min for the genetically modified E. coli mutants, E. coli WT, E. coli K-12, and S. epidermidis. (C) Semi-soft agar motility assays of E. coli WT, E. coli K-12, and S. epidermidis reveal that E. coli WT is significantly more motile than the K-12 strain (n = 4), while S. epidermidis is immotile. Optical microscope images after Ryu staining of E. coli WT and E. coli K-12 (right) reveal that the K-12 cells tend to have fewer flagella present. Scale bar represents 2 μm.

Article Snippet: As preliminary tests, the PRISM responses of three non-pathogenic bacteria strains, namely the laboratory mutant Escherichia coli ( E. coli ) K-12, clinically isolated E. coli (ATCC 25922, termed as WT), and Staphylococcus epidermidis ( S. epidermidis ATCC 14990), were observed over time, with Δ2nL (%) corresponding to the accumulation of cells in the topologies ( ).

Techniques: Chemotaxis Assay, Staining, Microscopy, Genetically Modified

Journal: bioRxiv

Article Title: Sticky Situations: Bacterial Attachment Deciphered by Interferometry of Silicon Microstructures

doi: 10.1101/793125

Figure Lengend Snippet: Substrate surface charge plays a role in bacterial adhesion. (A) AMINE Si surfaces yield a positive surface charge, while OX surfaces yield a negatively charged surface in motility buffer. (B) Zeta potential measurements of bacteria suspended in MB (n = 3) measure the surface charge of the cells. (C) Comparison bar graph of Δ2nL (%) PRISM values for OX and AMINE after 120 min of accumulation time. (D) Individual real-time PRISM accumulation curves for E. coli WT, E. coli K-12, and S. epidermidis on AMINE (positively charged) pore and pillar substrates. Note that the scale of the E. coli WT attachment curves is 5-times greater than that of E. coli K-12 and S. epidermidis. (E) False-colored SEM images of (i) E. coli WT on AMINE pores. (ii) E. coli WT on AMINE pillars reveal bridging between pillars and elongation of E. coli cells, in contrast to (iii) E. coli K-12 on AMINE pillars and (iv) S. epidermidis on AMINE pillars.

Article Snippet: As preliminary tests, the PRISM responses of three non-pathogenic bacteria strains, namely the laboratory mutant Escherichia coli ( E. coli ) K-12, clinically isolated E. coli (ATCC 25922, termed as WT), and Staphylococcus epidermidis ( S. epidermidis ATCC 14990), were observed over time, with Δ2nL (%) corresponding to the accumulation of cells in the topologies ( ).

Techniques: Zeta Potential Analyzer, Bacteria, Comparison