Amplify antimicrobial photo dynamic therapy efficacy with poly-beta-amino esters (PBAEs).

Light-activated antimicrobial agents (photosensitisers) are promising alternatives to antibiotics for the treatment of skin infections and wounds through antimicrobial photo dynamic therapy (aPDT); utilisation of this technique is still restricted by general low efficacy requiring long exposure time (in the order of tens of minutes) that make the treatment very resource intensive. We report for the first time the possibility of harvesting the cell penetrating properties of poly-beta-amino esters (PBAEs) in combination with toluidine blue O (TBO) to shorten aPDT exposure time. Candidates capable of inactivation rates 30 times quicker than pure TBO were discovered and further improvements through PBAE backbone optimisation could be foreseen.

Uniform sensing layer of immiscible enzyme-mediator compounds developed via a spray aerosol mixing technique towards low cost minimally invasive microneedle continuous glucose monitoring devices.

In this study, a uniformly mixed sensing layer of typically immiscible compounds, such as tetrathiafulvalene (TTF) mediator and glucose oxidase (GOx) enzyme, was developed using a simultaneous spray deposition technique ideal for mass production of glucose sensors at low cost while exhibiting enhanced amperometric response. For comparison, the sensors were fabricated via three different methods: conventional drop-cast of TTF and GOx compounds in subsequent layers (DL), spray deposition of the compounds in subsequent layers (SL), and spray mixing of the compounds as one uniform layer (SM). Uniformity of the sensing layers was investigated via Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX) techniques demonstrating an even distribution of the TTF and GOx throughout the sensing layer for the SM sensors.

Cobalt and Titanium nanoparticles influence on human osteoblast mitochondrial activity and biophysical properties of their cytoskeleton.

We investigated the biophysical effects (cell elasticity and spring constant) caused on Saos-2 human osteoblast-like cells by nanosized metal (Co and Ti) wear debris, as well as the adhesive characteristics of cells after exposure to the metal nanoparticles. Cell mitochondrial activity was investigated using the MTT assays; along with LDH assay, metal uptake, cell apoptosis and mineralisation output (alizarin red assay) of the cells. Osteoblasts mitochondrial activity was not affected by Ti nanoparticles at concentrations up to 1 mg/ml and by Cobalt nanoparticles at concentrations < 0.

Cobalt and titanium nanoparticles influence on mesenchymal stem cell elasticity and turgidity.

Bone cells are damaged by wear particles originating from total joint replacement implants. We investigated Mesenchymal stem cells (MSCs) nanomechanical properties when exposed to cobalt and titanium nanoparticles (resembling wear debris) of different sizes for up to 3days using AFM nanoindentation; along with flow-cytometry and MTT assay. The results demonstrated that cells exposed to increasing concentrations of nanoparticles had a lower value of elasticity and spring constant without significant effect on cell metabolic activity and viability but some morphological alteration (bleeping).

Influence of csgD and ompR on Nanomechanics, Adhesion Forces, and Curli Properties of E. coli.

Curli are bacterial appendages involved in the adhesion of cells to surfaces; their synthesis is regulated by many genes such as csgD and ompR. The expression of the two curli subunits (CsgA and CsgB) in Escherichia coli (E. coli) is regulated by CsgD; at the same time, csgD transcription is under the control of OmpR.

Cobalt, titanium and PMMA bone cement debris influence on mouse osteoblast cell elasticity, spring constant and calcium production activity.

Periprosthetic osteolysis and implant loosening are the outcomes of wear debris generation in total joint replacements. Wear debris formed from the implanted materials consisting of metals, polymers, ceramic and bone cement initiate the immune system response. Often osteoblasts, the principal cell type in bone tissue adjacent to the prostheses, are directly impacted.

Nanomechanical and surface properties of rMSCs post-exposure to CAP treated UHMWPE wear particles.

Unlabelled: Wear debris generated by ultra-high molecular weight polyethylene (UHMWPE) used in joint replacement devices has been of concern due to reductions of the implant longevity. Cold atmospheric plasma (CAP) has been used to improve the wear performance of UHMWPE. Our aim was to investigate the elastic and adhesive properties of rat mesenchymal stem cells (rMSCs), through AFM, after exposure to UHMWPE wear debris pre- and post-CAP treatment.

Adhesive forces and surface properties of cold gas plasma treated UHMWPE.

Cold atmospheric plasma (CAP) treatment was used on ultra-high molecular weight polyethylene (UHMWPE), a common articulating counter material employed in hip and knee replacements. UHMWPE is a biocompatible polymer with low friction coefficient, yet does not have robust wear characteristics. CAP effectively cross-links the polymer chains of the UHMWPE improving wear performance (Perni et al.

Surface roughness mediated adhesion forces between borosilicate glass and gram-positive bacteria.

It is well-known that a number of surface characteristics affect the extent of adhesion between two adjacent materials. One of such parameters is the surface roughness as surface asperities at the nanoscale level govern the overall adhesive forces. For example, the extent of bacterial adhesion is determined by the surface topography; also, once a bacteria colonizes a surface, proliferation of that species will take place and a biofilm may form, increasing the resistance of bacterial cells to removal.

Success and failure of colloidal approaches in adhesion of microorganisms to surfaces.

Biofilms are communities of cells attached to surfaces, their contributions to biological process may be either a benefit or a threat depending on the microorganism involved and on the type of substrate and environment. Biofilm formation is a complex series of steps; due to the size of microorganisms, the initial phase of biofilm formation, the bacterial adhesion to the surface, has been studied and modeled using theories developed in colloidal science. In this review the application of approaches such as Derjaguin, Landau, Verwey, Overbeek (DLVO) theory and its extended version (xDLVO), to bacterial adhesion is described along with the suitability and applicability of such approaches to the investigation of the interface phenomena regulating cells adhesion.