Novel bioelectrodes based on polysaccharide modified gold surfaces and electrochemically active Lactobacillus rhamnosus GG biofilms

Growth of Lactic Acid Bacteria on Gold—Influence of Surface Roughness and Chemical Composition

“…Copper samples covered with a gold layer (Au(E)) were synthesized by modifying the previously reported procedure [ 18 ]. Briefly, a copper foil was cut into coupons (2 cm × 1 cm) and degreased in acetone and ethanol.…”

“…Next, as-prepared electrodes were covered with a thin gold layer by sputter deposition (Quorum Q150T S sputter-coater, Quorum, Sussex, UK). In contrast to the previous procedure [ 18 ], a different commercially available gold solution (Auruna ® 556, 12 g·L −1 Au) was used to thicken the gold layer. An electrochemical deposition was carried out for 600 s at the constant current density of 1.5 mA·cm −2 by using a potentiostat (SP300, Biologic, Seyssinet-Pariset, France) in a conventional three-electrode cell, where a copper/sputtered gold substrate, platinum grid, and platinum wire were used as a working, counter, and reference electrodes, respectively.…”

“…Another example is Cupriavidus metallidurans strain, which can use gold compounds derived from the environment to synthesize golden nuggets [ 17 ]. What is more, our previous study revealed that the material based on an electrochemically produced gold layer covered with a cationic polysaccharide dramatically improved the adhesion of Lactobacillus rhamnosus GG bacteria and promoted its growth [ 18 ], which may be considered as one more exception from the generally accepted assumption concerning gold materials. These Gram-positive bacteria can be found in the human gastrointestinal tract (GIT) and are commonly used to produce probiotics [ 19 ] because of their beneficial health effects.…”

“…On the other hand, there are known systems that require microorganisms on the substrate surface. Our previous research demonstrated that modification of the negatively charged gold layer with a cationic polysaccharide might affect the attachment and proliferation of Lactobacillus rhamnosus GG bacteria [ 18 ]. A similar strategy was used for new material, but currently, the effect of the molecular weight (6, 40, and 100 kDa) of cationic dextrans on surface interactions with the lactic acid bacteria strains will also be studied.…”

In Situ Monitoring of Alkanethiol Self‐Assembly onto Zinc Selenide: The Role of Substrate Pretreatment and Its Implication in Bacterial Attachment

“…Such cell–cell organization was previously observed for LGG and other lactobacilli, and is associated with the presence of surface appendages on the cell wall of this bacterium. [ 17,45–47 ] LGG cells appeared green after the staining, which suggested the integrity of their membrane, despite the presence of positive charges known as potential bactericides. [ 48,49 ] Possibly, this effect was attributed to the fact that LGG, like other Gram‐positive bacteria, possess a thick peptidoglycan‐rich layer on their cell wall that could act as a protective layer against detrimental electrostatic forces.…”