Brain Wave-Like Signal Modulator by Ionic Nanochannel Rectifier Bridges

Smart modulation of bioelectric signals is of great significance for the development of brain-computer interfaces, bio-computers, and other technologies. The regulation and transmission of bioelectrical signals are realized through the synergistic action of various ion channels in organisms. The bionic nanochannels, which have similar physiological working environment and ion rectification as their biological counterparts, can be used to construct ion rectifier bridges to modulate the bioelectric signals. Here, the artificial smart ionic rectifier bridge with light response is constructed by anodic aluminum oxide (AAO)/poly (spiropyran acrylate) (PSP) nanochannels. The output ion current of the rectifier bridge can be switched between "ON" and "OFF" states by irradiation with UV and visible (Vis) light, and the conversion efficiency (η) of the system in "ON" state is ≈70.5%. The controllable modulation of brain wave-like signal can be realized by ionic rectifier bridge. The ion transport properties and processes of ion rectifier bridges are explained using theoretical calculations based on Poisson-Nernst-Planck (PNP) equations. These findings have significant implications for the understanding of the intelligent ionic circuit and combination of artificial smart ionic channels to organisms, which provide new avenues for development of intelligent ion devices.

Fast and slow light-induced changes in murine outer retina optical coherence tomography: complementary high spatial resolution functional biomarkers

Fast (seconds) and slow (minutes to hours) optical coherence tomography (OCT) responses to light stimulation have been developed to probe outer retinal function with higher spatial resolution than the classical full-field electroretinogram (ERG). However, the relationships between functional information revealed by OCT and ERG are largely unexplored. In this study, we directly compared the fast and slow OCT responses with the ERG. Fast responses [i.e. the optoretinogram (ORG)] are dominated by reflectance changes in the outer segment (OS) and the inner segment ellipsoid zone (ISez). The ORG OS response has faster kinetics and a higher light sensitivity than the ISez response, and both differ significantly with ERG parameters. Sildenafil-inhibition of phototransduction reduced the ORG light sensitivity, suggesting a complete phototransduction pathway is needed for ORG responses. Slower OCT responses were dominated by light-induced changes in the external limiting membrane to retinal pigment epithelium (ELM-RPE) thickness and photoreceptor-tip hyporeflective band (HB) magnitudes, with the biggest changes occurring after prolonged light stimulation. Mice with high (129S6/ev) vs. low (C57BL/6 J) ATP(adenosine triphosphate) synthesis efficiency show similar fast ORG, but dissimilar slow OCT responses. We propose that the ORG reflects passive physiology, such as water movement from photoreceptors, in response to the photocurrent response (measurable by ERG), whereas the slow OCT responses measure mitochondria-driven physiology in the outer retina, such as dark-provoked water removal from the subretinal space.

EAAT5 Glutamate Transporter-Mediated Inhibition in the Vertebrate Retina

Glutamate transporters typically remove glutamate from the synaptic cleft. In addition, all glutamate transporters have a chloride channel, which is opened upon glutamate binding to the transporter. There are five types of glutamate transporter (EAATs 1–5, excitatory amino acid transporters), which have distinct chloride conductances. Some EAATs that have low chloride conductances, remove glutamate from the synaptic cleft most effectively (e.g., EAAT1). By contrast, EAATs that have high chloride conductances, remove glutamate less effectively (e.g., EAAT5). We have studied EAAT5 in the retina. In the retina, light activates a chloride current, mediated by the glutamate activation of EAAT5. EAAT5 is not a significant contributor to lateral inhibition in the retina. Instead, it is the main source of autoinhibition to rod bipolar cells (RBCs). EAAT5-mediated inhibition has a substantial effect on synaptic transmission from RBCs to downstream retinal neurons.

Antifouling Nanofiltration Membrane Fabrication via Surface Assembling Light-Responsive and Regenerable Functional Layer

Membrane fouling, caused by aggregation of organics and microorganisms from filtrate on the membrane surface, seriously reduces the service life of a nanofiltration (NF) membrane. Developing facile and renewable antifouling modification methods without sacrificing separation properties of the membrane remain an imperative requirement. Herein, a thin-film composite (TFC) NF membrane with a light-responsive and regenerable functional layer (P-TFC) was fabricated via host-guest interactions between the azobenzene (guest) labeled functional polymers and the β-cyclodextrin (host) bonded membrane surface (H-TFC). The P-TFC-3 not only showed outstanding antifouling ability and high flux recovery ratio (FRR > 90% at the fourth antiadhesive test) but also exhibited enhanced water permeability (17.9 L m^-2 h^-1 bar^-1) and high selectivity (α_MgSO4^NaCl = 33.4 and fast antibiotics enrichment capacity) compared with the pristine membrane. Furthermore, when the functional layer was contaminated, it can be removed by ultraviolet light irradiation and a new functional layer can be rebuilt by adding fresh azobenzene labeled functional polymers. After several regeneration processes, the membranes still showed constant separation properties and high flux recovery ability (FRR > 90%). This work proposes an easy-to-assemble and regenerable surface modification strategy to endow TFC NF membranes with excellent fouling resistance and sustainable utilization ability while maintaining high separation properties.

A Cassava CPRF-2-like bZIP Transcription Factor Showed Increased Transcript Levels during Light Treatment

BACKGROUND

bZIP proteins participate in the regulation of gene expression, playing crucial roles in various biological processes in plants, including response to environmental changes. Luminosity is an environmental factor of extreme importance for plant metabolism, acting as a regulator of its growth and development. Despite advances in the identification of bZIP proteins in several plant species, studies on these transcription factors in cassava are lacking. Cassava (Manihot esculenta Crantz) is one of the most important food crops in tropical and subtropical regions, mainly in developing countries, where its storage root is a major source of calories for low-income people.

OBJECTIVES

Our main aim was the isolation of a cDNA sequence encoding a bZIP protein from cassava (MebZIP) as well as the in silico characterization of its nucleotide and deduced amino acid sequences. In addition, we evaluated the expression pattern of the MebZIP gene in response to light, and its possible relationship with regulation of the chalcone synthase (MeCHS) gene.

METHODS

RT-PCR and 3' and 5' RACE assays were used to isolate the full-length cDNA sequence of MebZIP. Bioinformatics tools were used to characterize the nucleotide and amino acid sequences of MebZIP. Semiquantitative RT-PCR assays were used to evaluate the expression levels of MebZIP and MeCHS genes.

RESULTS

We isolated the full-length cDNA sequence of MebZIP with a 1320-bp ORF encoding a deduced protein with a predicted molecular weight and isoelectric point of 47 kDa and 5.85, respectively. Comparative analyses with GenBank sequences showed high identity of MebZIP with bZIP CPRF-2 of Hevea brasiliensis (XP_021650934) and Petroselinum crispum (Q99090.2). Besides the basic region and leucine zipper domains, MebZIP contains putative conserved domains (D1- D4), found in parsley CPRF-2 and bZIP proteins closely related to this protein. Since CPRF proteins are known for their function in regulation of the CHS gene by light, we evaluated the expression levels of the MebZIP gene and the possible target gene to be regulated by MebZIP (the MeCHS gene) in cassava under light conditions. Semi-quantitative RT-PCR assays revealed that MebZIP transcription increased in response to white light, with maximum expression levels at 6 h of light exposure. On the other hand, the expression levels of the MeCHS gene were statistically constant in all samples, indicating that they were not influenced by the experimental conditions used here.

CONCLUSION

The putative MebZIP protein identified in this work contains the conserved domains (bZIP, D1-D4) that indicate its functionality, thus allowing it to be considered a new member of the bZIP transcription factor CPRF-2 family. The expression levels of the MebZIP gene increased during white light exposure, indicating a potential function in light-response in cassava.

Rapid and efficient multiple healing of flexible conductive films by near-infrared light irradiation

Healable, electrically conductive films are essential for the fabrication of reliable electronic devices to reduce their replacement and maintenance costs. Here we report the fabrication of near-infrared (NIR) light-enabled healable, highly electrically conductive films by depositing silver nanowires (AgNWs) on polycaprolactone (PCL)/poly(vinyl alcohol) (PVA) composite films. The bilayer film has sheet resistance as low as 0.25 Ω·sq(-1) and shows good flexibility to repeated bending/unbending treatments. Multiple healing of electrical conductivity lose caused by cuts of several tens of micrometers wide on the bilayer film can be conveniently achieved by irradiating the film with mild NIR light. The AgNW layer functions not only as an electrical conductor but also as a NIR light-induced heater to initiate the healing of PCL/PVA film, which then imparts its healability to the conductive AgNW layer.