Biofilm Inhibition and Antiviral Response of Cold Sprayed and Shot Peened Copper Surfaces: Effect of Surface Morphology and Microstructure.

Antibacterial properties of copper against planktonic bacteria population are affected by surface microstructure and topography. However, copper interactions with bacteria in a biofilm state are less studied. This work aims at better understanding the difference in biofilm inhibition of bulk, cold-sprayed, and shot-peened copper surfaces and gaining further insights on the underlying mechanisms using optical and scanning electron microscopy to investigate the topography and microstructure of the surfaces. The biofilm inhibition ability is reported for all surfaces. Results show that the biofilm inhibition performance of cold sprayed copper, while initially better, decreases with time and results in an almost identical performance than as-received copper after 18h incubation time. The shot-peened samples with a rough and ultrafine microstructure demonstrated an enhanced biofilm control, especially at 18 hr. The biofilm control mechanisms were explained by the diffusion rates and concentration of copper ions and the interaction between these ions and the biofilm, while surface topography plays a role in the bacteria attachment at the early planktonic state. Furthermore, the data suggest that surface topography plays a key role in antiviral activity of the materials tested, with a smooth surface being the most efficient.

Methylglyoxal-derived advanced glycation end products contribute to negative cardiac remodeling and dysfunction post-myocardial infarction.

Advanced glycation end-products (AGEs) have been associated with poorer outcomes after myocardial infarction (MI), and linked with heart failure. Methylglyoxal (MG) is considered the most important AGE precursor, but its role in MI is unknown. In this study, we investigated the involvement of MG-derived AGEs (MG-AGEs) in MI using transgenic mice that over-express the MG-metabolizing enzyme glyoxalase-1 (GLO1). MI was induced in GLO1 mice and wild-type (WT) littermates. At 6 h post-MI, mass spectrometry revealed that MG-H1 (a principal MG-AGE) was increased in the hearts of WT mice, and immunohistochemistry demonstrated that this persisted for 4 weeks. GLO1 over-expression reduced MG-AGE levels at 6 h and 4 weeks, and GLO1 mice exhibited superior cardiac function at 4 weeks post-MI compared to WT mice. Immunohistochemistry revealed greater vascular density and reduced cardiomyocyte apoptosis in GLO1 vs. WT mice. The recruitment of c-kit+ cells and their incorporation into the vasculature (c-kit+CD31+ cells) was higher in the infarcted myocardium of GLO1 mice. MG-AGEs appeared to accumulate in type I collagen surrounding arterioles, prompting investigation in vitro. In culture, the interaction of angiogenic bone marrow cells with MG-modified collagen resulted in reduced cell adhesion, increased susceptibility to apoptosis, fewer progenitor cells, and reduced angiogenic potential. This study reveals that MG-AGEs are produced post-MI and identifies a causative role for their accumulation in the cellular changes, adverse remodeling and functional loss of the heart after MI. MG may represent a novel target for preventing damage and improving function of the infarcted heart.

Integrated photothermal decontamination device for N95 respirators.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for the COVID-19 global pandemic has infected over 25 million people worldwide and resulted in the death of millions. The COVID-19 pandemic has also resulted in a shortage of personal protective equipment (PPE) in many regions around the world, particularly in middle- and low-income countries. The shortages of PPE, such as N95 respirators, is something that will persist until an effective vaccine is made available. Thus, devices that while being easy to operate can also be rapidly deployed in health centers, and long-term residences without the need for major structural overhaul are instrumental to sustainably use N95 respirators. In this report, we present the design and validation of a decontamination device that combines UV-C & B irradiation with mild-temperature treatment. The device can decontaminate up to 20 masks in a cycle of < 30 min. The decontamination process did not damage or reduce the filtering capacity of the masks. Further, the efficacy of the device to eliminate microbes and viruses from the masks was also evaluated. The photothermal treatment of our device was capable of eradicating > 99.9999% of the bacteria and > 99.99% of the virus tested.

Heparin mimetic peptide nanofiber gel promotes regeneration of full thickness burn injury.

Burn injuries are one of the most common types of trauma worldwide, and their unique physiology requires the development of specialized therapeutic materials for their treatment. Here, we report the use of synthetic, functional and biodegradable peptide nanofiber gels for the improved healing of burn wounds to alleviate the progressive loss of tissue function at the post-burn wound site. These bioactive nanofiber gels form scaffolds that recapitulate the structure and function of the native extracellular matrix through signaling peptide epitopes, which can trigger angiogenesis through their affinity to basic growth factors. In this study, the angiogenesis-promoting properties of the bioactive scaffolds were utilized for the treatment of a thermal burn model. Following the excision of necrotic tissue, bioactive gels and control solutions were applied topically onto the wound area. The wound healing process was evaluated at 7, 14 and 21 days following injury through histological observations, immunostaining and marker RNA/protein analysis. Bioactive peptide nanofiber-treated burn wounds formed well-organized and collagen-rich granulation tissue layers, produced a greater density of newly formed blood vessels, and exhibited increased re-epithelialization and skin appendage development with minimal crust formation, while non-bioactive peptide nanofibers and the commercial wound dressing 3M™ Tegaderm™ did not exhibit significant efficiency over sucrose controls. Overall, the heparin-mimetic peptide nanofiber gels increased the rate of repair of burn injuries and can be used as an effective means of facilitating wound healing.