How living systems respond to weak electromagnetic fields represents one of the major unsolved challenges in sensory biology. Recent evidence has implicated cryptochrome, an evolutionarily conserved flavoprotein receptor, in magnetic field responses of organisms ranging from plants to migratory birds. However, whether cryptochromes fulfill the criteria to function as biological magnetosensors remains to be established. Currently, theoretical predictions on the underlying mechanism of chemical magnetoreception have been supported by experimental observations that exposure to radiofrequency (RF) in the MHz range disrupt bird orientation and mammalian cellular respiration. Here we show that, in keeping with certain quantum physical hypotheses, a weak 7 MHz radiofrequency magnetic field significantly reduces the biological responsivity to blue light of the cryptochrome receptor cry1 in Arabidopsis seedlings. Using an in vivo phosphorylation assay that specifically detects activated cryptochrome, we demonstrate that RF exposure reduces conformational changes associated with biological activity. RF exposure furthermore alters cryptochrome-dependent plant growth responses and gene expression to a degree consistent with theoretical predictions. To our knowledge this represents the first demonstration of a biological receptor responding to RF exposure, providing important new implications for magnetosensing as well as possible future applications in biotechnology and medicine.

The recent study focused on the improvement of polydimethylsiloxane (PDMS) surface biocompatibility as the most commonly used biomaterial in maxillofacial prostheses for intraoral defects. Biocompatibility enhances tissue‐prosthesis integration to prevent implant dislocation; to evaluate the parameter the study conducted at different times of oxygen plasma exposure. Scanning electron microscopy, contact angle measurement, atomic force microscopy and above all, cell cultivation—as a crucial factor in biocompatibility—carried out to investigate the samples’ characteristics. An improved PDMS biocompatibility is expected; referring to the fact that an “optimal range”—not necessarily the maximum values—of surface hydrophilicity and roughness could induce an enhanced cell attachment on the PDMS surface, an “optimum time” of O2 plasma exposure is required to meet this goal. Considering the O2 plasma setup items, the ratio of PDMS components and fabrication process in the current survey, 2.5‐min O2 plasma exposure well suited to PDMS surface cell adhesion.

A clinically approved, tissue engineered graft is needed as an alternative for small‐diameter artery replacement. Collagen type I is commonly investigated for naturally derived grafts. However, collagen promotes thrombosis, currently requiring a graft pre‐seeding step. This study investigates unique impacts of blending low collagen amounts with synthetic polymers on scaffold platelet response, which would allow for viable acellular grafts that can endothelialize in vivo. While platelet adhesion and activation are confirmed to be high with 50% collagen samples, low collagen ratios surprisingly exhibit the opposite, anti‐thrombogenic effect. Different platelet interactions in these blended materials can be related to collagen structure. Low collagen ratios show homogenous distribution of the components within individual fibers. Importantly, blended collagen scaffolds exhibit significant differences from gelatin scaffolds, including retaining percentage of collagen after incubation. These findings correlate with functional benefits including better endothelial cell spreading on collagen versus gelatin blended materials. This appears to differ from the current paradigm that processing with harsh solvents will irreversibly denature collagen into less desirable gelatin, but an important distinction is the interaction between collagen and synthetic materials during processing. Overall, excellent anti‐thrombogenic properties of low collagen blends and benefits after grafting show promise for this vascular graft strategy.

The development of tissue-engineered products has been limited by lack of a perfused microvasculature that delivers nutrients and maintains cell viability. Current strategies to promote vascularization such as additive three-dimensional printing techniques have limitations. This study validates the use of an ultra-fast laser subtractive printing technique to generate capillary-sized channels in hydrogels prepopulated with cells by demonstrating cell viability relative to the photodisrupted channels in the gel. The system can move the focal spot laterally in the gel at a rate of 2500 mm/s by using a galvanometric scanner to raster the in plane focal spot. A Galilean telescope allows z-axis movement. Blended hydrogels of polyethylene glycol and collagen with a range of optical clarities, mechanical properties and swelling behavior were tested to demonstrate that the subtractive printing process for writing vascular channels is compatible with all of the blended hydrogels tested. Channel width and patterns were controlled by adjusting the laser energy and focal spot positioning, respectively. After treatment, high cell viability was observed at distances greater than or equal to 18 μm from the fabricated channels. Overall, this study demonstrates a flexible technique that has the potential to rapidly generate channels in tissue-engineered constructs.

In this study, we characterized the bioenergetic response of the Lund human mesencephalic (LUHMES) cell line and a mouse astrocyte cell line to oxidative stress. Extracellular hydrogen peroxide  (H2O2) levels and bioenergetic response were investigated in these cell lines after exposure to paraquat (PQ), a redox cycling compound that causes oxidative stress in cells. We used extracellular flux analysis to measure mitochondrial function in adherent astrocytes and LUHMES cells. Extracellular H2O2 was measured fluorometrically. H2O2 levels increased in both cell lines after exposure to 5 µM PQ for 18 h; however, the extent of H2O2 increase with astrocytes was significantly lower than that with LUHMES cells (33% vs. 67%). Measurements of basal mitochondrial respiration showed that PQ almost completely eliminated oxygen consumption rate (OCR) in astrocytes and significantly reduced it in LUHMES cells. Notably, OCR in LUHMES cells was higher than that in astrocytes, indicating that neuronal cells maintain higher oxidative metabolism than glial cells, which is also consistent with higher energy demands of the neuronal cells. Moreover, LUHMES cells exhibited a higher amount of adenosine triphosphate (ATP) being produced by oxidative phosphorylation than by glycolysis. In contrast, astrocytes demonstrated a higher glycolytic capacity and glycolytic reserve than LUHMES cells and higher ATP production rate by glycolysis than its production by mitochondrial oxidative metabolism. Collectively, this study showed the differential bioenergetic responses between astrocytes and LUHMES cells in responding to oxidative stress and the findings may provide insights into the mitochondrial reserve capacity in neurons and astrocytes in responding to oxidative stress. (First online: Mar 30, 2021)