A bionic self-driven retinomorphic eye with ionogel photosynaptic retina.

Bioinspired bionic eyes should be self-driving, repairable and conformal to arbitrary geometries. Such eye would enable wide-field detection and efficient visual signal processing without requiring external energy, along with retinal transplantation by replacing dysfunctional photoreceptors with healthy ones for vision restoration. A variety of artificial eyes have been constructed with hemispherical silicon, perovskite and heterostructure photoreceptors, but creating zero-powered retinomorphic system with transplantable conformal features remains elusive. By combining neuromorphic principle with retinal and ionoelastomer engineering, we demonstrate a self-driven hemispherical retinomorphic eye with elastomeric retina made of ionogel heterojunction as photoreceptors. The receptor driven by photothermoelectric effect shows photoperception with broadband light detection (365 to 970 nm), wide field-of-view (180°) and photosynaptic (paired-pulse facilitation index, 153%) behaviors for biosimilar visual learning. The retinal photoreceptors are transplantable and conformal to any complex surface, enabling visual restoration for dynamic optical imaging and motion tracking.

Engineering the next-generation synthetic cell factory driven by protein engineering.

Synthetic cell factory offers substantial advantages in economically efficient production of biofuels, chemicals, and pharmaceutical compounds. However, to create a high-performance synthetic cell factory, precise regulation of cellular material and energy flux is essential. In this context, protein components including enzymes, transcription factor-based biosensors and transporters play pivotal roles. Protein engineering aims to create novel protein variants with desired properties by modifying or designing protein sequences. This review focuses on summarizing the latest advancements of protein engineering in optimizing various aspects of synthetic cell factory, including: enhancing enzyme activity to eliminate production bottlenecks, altering enzyme selectivity to steer metabolic pathways towards desired products, modifying enzyme promiscuity to explore innovative routes, and improving the efficiency of transporters. Furthermore, the utilization of protein engineering to modify protein-based biosensors accelerates evolutionary process and optimizes the regulation of metabolic pathways. The remaining challenges and future opportunities in this field are also discussed.

Mimicking Bidirectional Inhibitory Synapse Using a Porous-Confined Ionic Memristor with Electrolyte/Tris(4-aminophenyl)amine Neurotransmitter.

Ionic memristors can emulate brain-like functions of biological synapses for neuromorphic technologies. Apart from the widely studied excitatory-excitatory and excitatory-inhibitory synapses, reports on memristors with the inhibitory-inhibitory synaptic behaviors remain a challenge. Here, the first biaxially inhibited artificial synapse is demonstrated, consisting of a solid electrolyte and conjugated microporous polymers bilayer as neurotransmitter, with the former serving as an ion reservoir and the latter acting as a confined transport. Due to the migration, trapping, and de-trapping of ions within the nanoslits, the device poses inhibitory synaptic plasticity under both positive and negative stimuli. Remarkably, the artificial synapse is able to maintain a low level of stable nonvolatile memory over a long period of time (≈60 min) after multiple stimuli, with feature-inferencing/-training capabilities of neural node in neuromorphic computing. This work paves a reliable strategy for constructing nanochannel ionic memristive materials toward fully inhibitory synaptic devices.

Stretchable, Washable, and Anti-Ultraviolet i-Textile-Based Wearable Device for Motion Monitoring.

Smart textiles with multifunction and highly stable performance are essential for their application in wearable electronics. Despite the advancement of various smart textiles through the decoration of conductive materials on textile surfaces, improving their stability and functionality remains a challenging topic. In this study, we developed an ionic textile (i-textile) with air permeability, water resistance, UV resistance, and sensing capabilities through in situ photopolymerization of ionogel onto the textile surface. The i-textile presents air permeability comparable to that of bare textile while possessing enhanced UV resistance. Remarkably, the i-textile maintains excellent electrical properties after washing 20 times or being subjected to 300 stretching cycles at 30% tension. When applied to human joint motion detection, the i-textile-based sensors can effectively distinguish joint motion based on their sensitivity and response speed. This research presents a novel method for developing smart textiles that further advances wearable electronics.

Multidimensional Transport Experiment and Simulation of Chloride Ions in Concrete Subject to Simulated Dry and Wet Cycles in a Marine Environment.

Chloride ion erosion is an important factor affecting the durability of marine engineering concrete. In particular, concrete structures in wave splash and tidal zones are subjected to dry and wet cycles and multidimensional diffusion of chloride ions. To investigate the intricate diffusion of chloride ions within concrete under these dynamic conditions, we devised a comprehensive experiment. This experiment encompasses multiple dimensions, involving dry and wet cycles, as well as static immersion. The experiment intends to reveal how chloride ions are distributed in the concrete and clarify the changes that occur in its microstructure. Based on Fick's second law, the multidimensional diffusion model of chloride ions in concrete under the dry and wet cycles and static immersion was established by comprehensively considering the effects of chloride ion exposure time, environment temperature, relative humidity, and the action of dry and wet cycles. The results show that, under the same conditions, the chloride content in concrete decreases with the increase in penetration depth but increases with the increase in the chloride diffusion dimension and exposure time. Dry and wet cycles and multidimensional diffusion of chloride ions increase the development of cracks and pores in the concrete structure and generate large quantities of C3A·CaCl2·10H2O, which will exacerbate the chloride ion transport rate and penetration depth of concrete. Under the same exposure time and penetration depth, the chloride ion content in concrete under two-dimensional (2D) and three-dimensional (3D) diffusion under dry and wet cycles was 1.09~4.08 times higher than that under one-dimensional (1D) diffusion. The correlation coefficients between the simulation results of the multidimensional transport model of chloride ions in concrete under multi-factor coupling and the experimental results were all greater than 0.95, and the model can be utilized to predict the distribution of chloride ion concentration in concrete.

Nearly Panoramic Neuromorphic Vision with Transparent Photosynapses.

Neuromorphic vision based on photonic synapses has the ability to mimic sensitivity, adaptivity, and sophistication of bio-visual systems. Significant advances in artificial photosynapses are achieved recently. However, conventional photosyanptic devices normally employ opaque metal conductors and vertical device configuration, performing a limited hemispherical field of view. Here, a transparent planar photonic synapse (TPPS) is presented that offers dual-side photosensitive capability for nearly panoramic neuromorphic vision. The TPPS consisting of all two dimensional (2D) carbon-based derivatives exhibits ultra-broadband photodetecting (365-970 nm) and ≈360° omnidirectional viewing angle. With its intrinsic persistent photoconductivity effect, the detector possesses bio-synaptic behaviors such as short/long-term memory, experience learning, light adaptation, and a 171% pair-pulse-facilitation index, enabling the synapse array to achieve image recognition enhancement (92%) and moving object detection.

Engineering acetyl-CoA metabolism to enhance stress tolerance of yeast by regulating membrane functionality.

Zygosaccharomyces rouxii has excellent fermentation performance and good tolerance to osmotic stress. Acetyl-CoA is a crucial intermediate precursor in the central carbon metabolic pathway of yeast. This study investigated the effect of engineering acetyl-CoA metabolism on the membrane functionality and stress tolerance of yeast. Firstly, exogenous supplementation of acetyl-CoA improved the biomass and the ability of unsaturated fatty acid synthesis of Z. rouxii under salt stress. Q-PCR results suggested that the gene ACSS (coding acetyl-CoA synthetase) was significantly up-expressed. Subsequently, the gene ACSS from Z. rouxii was transformed and heterologously expressed in S. cerevisiae. The recombinant cells exhibited better multiple stress (salt, acid, heat, and cold) tolerance, higher fatty acid contents, membrane integrity, and fluidity. Our findings may provide a suitable means to enhance the stress tolerance and fermentation efficiency of yeast under harsh fermentation environments.

Theoretical Insights into Potential-Dependent C-C Bond Formation Mechanisms during CO2 Electroreduction into C2 Products on Cu(100) at Simulated Electrochemical Interfaces.

An improved CO coverage-dependent electrochemical interface model with an explicit solvent effect on Cu(100) is presented in this paper, by which theoretical insights into the potential-dependent C-C bond formation pathways occurring in CO2 electrochemical reduction to C2 products can be obtained. Our present studies indicate that CHO is a crucial intermediate toward C1 products on Cu(111), and dimer OCCO is found to not be a viable species for the production of C2 products on Cu(100). The reaction pathway of CHO with CO and CHO dimerization into dimers COCHO and CHOCHO may be C-C bond formation mechanisms at low overpotential. However, at medium overpotential, C-C bond coupling takes place preferentially through the reaction of COH with CO species and COH dimerization into dimers COCOH and COHCOH. The formed dimers COCHO, CHOCOH, and CHOCHO via reactions of CHO with CO, COH, and CHO species may lead to C2 products, which are regarded as C-C bond formation mechanisms at high overpotential. The difference of obtained adsorption isotherms of CO on Cu(100) with that of Cu(111) may be able to explain the effect of the crystal face of Cu on product selectivity. The excellent consistencies between our present obtained conclusions and the available experimental reports and partial theoretical studies validate the reasonability of the present employed methodology, which can be also used to systematically study potential-dependent CO2 electroreduction pathways toward C2 products on Cu(100) or other metal catalysts.

Mechanistic insights into potential dependence of CO electrochemical reduction into C1 products based on a H coverage-dependent Cu(111)/H2O interface model.

A H coverage-dependent Cu(111)/H2O interface model incorporated with electronic structure analysis is employed to investigate the potential dependence of CO electroreduction into C1 products with the aim of solving the long dispute over CO2 electrocatalytic reduction mechanisms. The results indicate that CH4 formation mainly proceeds through CO, CHO, CH2O, CH2OH and CHx (x = 2 and 3) species at various applied potentials. CH3OH may be formed via a CH3O intermediate at high overpotential and the present study can confirm that CH3OH is only produced in a trace amount as detected in experiments. The high overpotential results in the formation of CH4, explaining the experimentally required high overpotential on Cu. The calculated energetics concludes that CO electroreduction into CHO may be a potential-limiting step, being regarded as the origin of the required high overpotentials for CO2 electroreduction in this paper. The electronic structure calculations show that more electronic transfer to the adsorbed H atoms occurs with increasing H coverage, which can be considered as the origin of the more negative electrode potentials. Interestingly, it is observed that the s orbital of the C atom in the valence shell of the adsorbed CO molecule gains more and more electrons, whereas the s orbital of the O atom gains less and less electrons, and even loses electrons with increasing H coverage, implying easier and easier proton transfer towards the C-center site. Thus, the easier occurrence of CO electroreduction may be ascribed to the more electron transfer into the s orbital of the C atom at high overpotential. We believe that the present study represents theoretical progress to systematically study potential-dependent CO2 electroreduction mechanisms on Cu electrodes.

Potential-Dependent Competitive Electroreduction of CO2 into CO and Formate on Cu(111) from an Improved H Coverage-Dependent Electrochemical Model with Explicit Solvent Effect.

An improved density functional theory-based H coverage-dependent electrochemical model with explicit solvent effect is proposed for Cu(111), which is used to identify potential-dependent initial competitive CO2 electroreduction pathways considering HER. We find that a chemisorbed CO2 molecule at the present electrode/aqueous interface can be spontaneously formed and the overpotentials can affect its coordination pattern. The Eley-Rideal mechanism may be more favorable during the initial CO2 electroreduction into CO, whereas chemisorbed CO2 reacting with adsorbed H into HCOO- via the Langmuir-Hinshelwood mechanism is more facile to occur. The analyses of energetics suggest that the low overpotentials have a negligible influence on CO and HCOO- formation, and HCOO- species with monodentate and bidentate configurations may also parallelly form with the surmountable barriers at room temperature. However, the high potentials have an interruptive effect on initial CO2 electroreduction because of the significantly increased barriers, indicating that the chemisorbed CO2 can be stabilized by imposing more negative potentials and thus going against initial CO2 electroreduction. By analyzing the competing HER with initial CO2 electroreduction into CO, we find that HER is competitive with initial CO formation because of the required lower overpotentials. Simultaneously, the present study shows that the blocked Cu surface by adsorbed H and CO can explain why the initial CO formation pathway is unfavorable at the high overpotentials. Our present conclusions can also confirm the previous experimental report on initial formation of CO and HCOO-.