Surface Architecture Influences the Rigidity of Cells.

Atomic force microscopy (AFM) was used to investigate the morphology and rigidity of the opportunistic pathogenic yeast, ATCC 10231, during its attachment to surfaces of three levels of nanoscale surface roughness. Non-polished titanium (npTi), polished titanium (pTi), and glass with respective average surface roughness () values of 389 nm, 14 nm, and 2 nm, kurtosis () values of 4, 16, and 4, and skewness () values of 1, 4, and 1 were used as representative examples of each type of nanoarchitecture. Thus, npTi and glass surfaces exhibited similar and values but highly disparate .

Nanoscale Surface Roughness Influences Biofilm Formation.

The microbial contamination of surfaces presents a significant challenge due to the adverse effects associated with biofilm formation, particularly on implantable devices. Here, the attachment and biofilm formation of the opportunistic human pathogen, ATCC 10231, were studied on surfaces with decreasing magnitudes of nanoscale roughness. The nanoscale surface roughness of nonpolished titanium, polished titanium, and glass was characterized according to average surface roughness, skewness, and kurtosis.

Three-Dimensional Hierarchical Wrinkles on Polymer Films: From Chaotic to Ordered Antimicrobial Topographies.

Microbial contamination of polymer surfaces has become a significant challenge in domestic, industrial, and biomedical applications. Recent progress in our understanding of how topographical features of different length scales can be used to effectively and selectively control the attachment and proliferation of different cell types has provided an alternative strategy for imparting antibacterial activity to these surfaces. Among the well-recognized engineered models of antibacterial surface topographies, self-organized wrinkles have shown particular promise with respect to their antimicrobial characteristics.

The idiosyncratic self-cleaning cycle of bacteria on regularly arrayed mechano-bactericidal nanostructures.

Nanostructured mechano-bactericidal surfaces represent a promising technology to prevent the incidence of microbial contamination on a variety of surfaces and to avoid bacterial infection, particularly with antibiotic resistant strains. In this work, a regular array of silicon nanopillars of 380 nm height and 35 nm diameter was used to study the release of bacterial cell debris off the surface, following inactivation of the cell due to nanostructure-induced rupture. It was confirmed that substantial bactericidal activity was achieved against Gram-negative Pseudomonas aeruginosa (85% non-viable cells) and only modest antibacterial activity towards Staphylococcus aureus (8% non-viable cells), as estimated by measuring the proportions of viable and non-viable cells via fluorescence imaging.

Three-Dimensional Organization of Self-Encapsulating Bacterial Cells.

Self-organized bacteria have been the subject of interest for a number of applications, including the construction of microbial fuel cells. In this paper, we describe the formation of a self-organized, three-dimensional network that is constructed using B-1280 cells in a hydrogel consisting of poly(vinyl alcohol) (PVA) with -vinyl pyrrolidone (VP) as a cross-linker, in which the bacterial cells are organized in a particular side-by-side alignment. We demonstrated that nonmotile cells are able to reorganize themselves, transforming and utilizing PVA-VP polymeric networks through the molecular interactions of bacterial extracellular polysaccharide (EPS) components such as acetan, cellulose, dextran, and levan.

Role of topological scale in the differential fouling of Pseudomonas aeruginosa and Staphylococcus aureus bacterial cells on wrinkled gold-coated polystyrene surfaces.

Wrinkled patterns, which possess an extensive surface area over a limited planar space, can provide surface features ranging across the nano- and microscale that have become an engineering material with the flexibility to be tuneable for a number of technologies. Here, we investigate the surface parameters that influence the attachment response of two model bacteria (P. aeruginosa and S.

Adsorption of Human Plasma Albumin and Fibronectin onto Nanostructured Black Silicon Surfaces.

The protein adsorption of two human plasma proteins-albumin (Alb) and fibronectin (Fn)-onto synthetic nanostructured bactericidal material-black silicon (bSi) surfaces (that contain an array of nanopillars) and silicon wafer (nonstructured) surfaces-was investigated. The adsorption behavior of Alb and Fn onto two types of substrata was studied using a combination of complementary analytical techniques. A two-step Alb adsorption mechanism onto the bSi surface has been proposed.

Impact of confining 3-D polymer networks on dynamics of bacterial ingress and self-organisation.

Studies of microbial interactions during motility, micro-structuring and colonisation have predominately been limited to surface associated bacteria involving materials such as semi-solid biomolecular hydrogels and thin liquid films. Recently, these surfaces have been extended to synthetic polymers where they provide defined chemistries and structural properties. However, precise details of microbial ingress into the confined fluid volume of synthetic 3-D hydrogel networks and their subsequent microstructuring remain to be defined.