Chronic non-healing wounds show delayed and incomplete healing processes and in turn expose patients to a high risk of infection. Treatment currently focuses on dressings that prevent microbial infiltration and keep a balanced moisture and gas exchange environment. Antibacterial delivery from dressings has existed for some time, with responsive systems now aiming to trigger release only if infection occurs. Simultaneously, approaches that stimulate cell proliferation in the wound and encourage healing have been developed. Interestingly, few dressings appear capable of simultaneously impairing or treating infection and encouraging cell proliferation/wound healing. Electrospinning is a simple, cost-effective, and reproducible process that can utilize both synthetic and natural polymers to address these specific wound challenges. Electrospun meshes provide high-surface area, micro-porosity, and the ability to load drugs or other biomolecules into the fibers. Electrospun materials have been used as scaffolds for tissue engineering for a number of years, but there is surprisingly little literature on the interactions of fibers with bacteria and co-cultures of cells and bacteria. This Review examines the literature and data available on electrospun wound dressings and the research that is required to develop smart multifunctional wound dressings capable of treating infection and healing chronic wounds.

Infrared stimulation offers an alternative to electrical stimulation of neuronal tissue, with potential for direct, non-contact activation at high spatial resolution. Conventional methods of infrared neural stimulation (INS) rely on transient heating due to the absorption of relatively intense laser beams by water in the tissue. However, the water absorption also limits the depth of penetration of light in tissue. Therefore, the use of a near-infrared laser at 780 nm to stimulate cultured rat primary auditory neurons that are incubated with silica-coated gold nanorods (Au NRs) as an extrinsic absorber is investigated. The laser-induced electrical behavior of the neurons is observed using whole-cell patch clamp electrophysiology. The nanorod-treated auditory neurons (NR-ANs) show a significant increase in electrical activity compared with neurons that are incubated with non-absorbing silica-coated gold nanospheres and control neurons with no gold nanoparticles. The laser-induced heating by the nanorods is confirmed by measuring the transient temperature increase near the surface of the NR-ANs with an open pipette electrode. These findings demonstrate the potential to improve the efficiency and increase the penetration depth of INS by labeling nerves with Au NRs and then exposing them to infrared wavelengths in the water window of tissue.

Near edge X-ray absorption fine structure (NEXAFS) has been employed to provide insight into the chemical nature of nitrogen in deposits formed from plasmas of allylamine and propylamine. The nitrogen K-edge spectra of these materials unambiguously demonstrate the presence of significant quantities of sp or sp 2 hybridized nitrogen. This finding, in conjunction with carbon K-edge spectra, strongly indicates that there is a substantial level of dehydrogenation during the plasma polymerization process resulting in the formation of imine groups and, at high power, nitrile groups in addition to sp 3 hybridized amines. Comparison with standard polymers indicates that amide formation (following a few days exposure to atmosphere) is negligible. These findings suggest that the hydrolysis of aminated plasma polymers may be important in their long-term aging.

The characterization of adsorbed protein films with ultrahigh vacuum (UHV) surface analysis techniques requires dehydration of the samples, which can cause significant alterations in protein conformation. Trehalose coating was used in this study to inhibit these conformational changes from occurring when preparing samples for analysis in UHV. Surface plasmon resonance (SPR) analysis showed that air-dried films of trehalose-stabilized antiferritin and anti-IgM both retained a significant proportion of their hydrated antigen binding activity. In contrast, air-drying without trehalose protection resulted in the adsorbed protein films losing most of their antigen binding activity. Structural differences between trehalose-stabilized and unstabilized protein films were then analyzed with static time-of-flight secondary ion mass spectrometry (ToF−SIMS). By application of principle component analysis (PCA) to the static ToF−SIMS spectra, the biological activity difference observed in SPR was correlated to changes in protein conformation. Trehalose-protected proteins retained a greater degree of their original conformation than the unprotected proteins. This suggests coating adsorbed protein films with trehalose prior to air-drying and introduction into UHV allows ToF−SIMS to analyze adsorbed proteins in a state that is more representative of their actual structure in an aqueous environment.

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