Computation-Driven Rational Design of Self-Assembled Short Peptides for Catalytic Hydrogen Production.

Self-assembling peptides represent a captivating area of study in nanotechnology and biomaterials. This interest is largely driven by their unique properties and the vast application potential across various fields such as catalytic functions. However, design complexities, including high-dimensional sequence space and structural diversity, pose significant challenges in the study of such systems. In this work, we explored the possibility of self-assembled peptides to catalyze the hydrolysis of hydrosilane for hydrogen production using ab initio calculations and carried out wet-lab experiments to confirm the feasibility of these catalytic reactions under ambient conditions. Further, we delved into the nuanced interplay between sequence, structural conformation, and catalytic activity by combining modeling with experimental techniques such as transmission electron microscopy and nuclear magnetic resonance and proposed a dual mode of the microstructure of the catalytic center. Our results reveal that although research in this area is still at an early stage, the development of self-assembled peptide catalysts for hydrogen production has the potential to provide a more sustainable and efficient alternative to conventional hydrogen production methods. In addition, this work also demonstrates that a computation-driven rational design supplemented by experimental validation is an effective protocol for conducting research on functional self-assembled peptides.

Fabrication of elliptical-silica microfiber for ultrasound detection.

Elliptical shape microfiber enables many higher order modes compared with a circular microfiber. The small difference in the optical path length among many modes enabled multi-resonance peaks with high contrast in Mach-Zehnder (MZI) interferometers, which allows a large dynamic range and minimum detection sensitivity for broadband ultrasound sensing. In this paper, we present the design and fabrication of an ultra-compact elliptical-silica microfiber utilizing off-axis flame-drawing for ultrasound detection. The narrow transmission peak showed high contrast for ultrasensitive ultrasound wave detection. With a major-axis diameter of 6.25 µm, the elliptical-silica microfiber sensor exhibits a broadband ultrasound frequency response spanning from 20 kHz to 38.5 MHz. Furthermore, it achieves a signal-to-noise ratio (SNR) of up to 80 dB at 1 MHz, which is the resonance frequency of the microfiber and the linear response under driving voltages of 3-10 V for the PZT ultrasound generator. This low-cost microfiber sensor offers exceptional sensitivity across a broad ultrasonic bandwidth response, making it an ideal choice for nondestructive testing (NDT) and medical imaging applications. Its compact size and immunity to electric and magnetic fields further enhance its utility in various environments.

A Pt1Pd Single-Atom Alloy Nanozyme with Boosted Enzyme-Like Activity for Efficient Photo-Mediated Tumor Therapy.

Single-atom nanozymes (SAzymes) are emerging natural enzyme mimics and have attracted much attention in the biomedical field. SAzymes with Metal─Nx sites designed on carbon matrixes are currently the mainstream in research. It is of great significance to further expand the types of SAzymes to enrich the nanozyme library. Single-atom alloys (SAAs) are a material in which single-atom metal sites are dispersed onto another active metal matrix, and currently, there is limited research on their enzyme-like catalytic performance. In this work, a biodegradable Pt1Pd SAA is fabricated via a simple galvanic replacement strategy, and for the first time reveals its intrinsic enzyme-like catalytic performance including catalase-, oxidase-, and peroxidase-like activities, as well as its photodynamic effect. Experimental characterizations demonstrate that the introduction of single-atom Pt sites contributes to enhancing the affinity of Pt1Pd single-atom alloy nanozyme (SAAzyme) toward substrates, thus exhibiting boosted catalytic efficiency. In vitro and in vivo experiments demonstrate that Pt1Pd SAAzyme exhibits a photo-controlled therapeutic effect, with a tumor inhibition rate of up to 100%. This work provides vital guidance for opening the research direction of SAAs in enzyme-like catalysis.

Engineering Atomically Dispersed Cu-N1S2 Sites via Chemical Vapor Deposition to Boost Enzyme-Like Activity for Efficient Tumor Therapy.

Single-atom nanozymes (SAzymes), with well-defined and uniform atomic structures, are an emerging type of natural enzyme mimics. Currently, it is important but challenging to rationally design high-performance SAzymes and deeply reveal the interaction mechanism between SAzymes and substrate molecules. Herein, this work reports the controllable fabrication of a unique Cu-N1S2-centred SAzyme (Cu-N/S-C) via a chemical vapor deposition-based sulfur-engineering strategy. Benefiting from the optimized geometric and electronic structures of single-atom sites, Cu-N/S-C SAzyme shows boosted enzyme-like activity, especially in catalase-like activity, with a 13.8-fold increase in the affinity to hydrogen peroxide (H2O2) substrate and a 65.2-fold increase in the catalytic efficiency when compared to Cu-N-C SAzyme with Cu-N3 sites. Further theoretical studies reveal that the increased electron density around single-atom Cu is achieved through electron redistribution, and the efficient charge transfer between Cu-N/S-C and H2O2 is demonstrated to be more beneficial for the adsorption and activation of H2O2. The as-designed Cu-N/S-C SAzyme possesses an excellent antitumor effect through the synergy of catalytic therapy and oxygen-dependent phototherapy. This study provides a strategy for the rational design of SAzymes, and the proposed electron redistribution and charge transfer mechanism will help to understand the coordination environment effect of single-atom metal sites on H2O2-mediated enzyme-like catalytic processes.

Intensity self-compensation method against multi-factors for polarization-based Fabry-Perot interrogation system.

Phase interrogation methods for fiber-optic Fabry-Perot (F-P) sensors may inevitably fail in the field due to the influences of irrelevant factors on signal intensity. To address this severe problem, this Letter proposes an intensity self-compensation method (ISCM) to eliminate the consecutive signal fluctuations of a polarization-based F-P interrogation system caused by multiple factors. By providing only the initial intensities of the reference signals, this attempt realizes the real-time intensity compensation of the output signals without affecting their quadrature relationship. Consecutive intensity fluctuations caused by variation of light source power, fiber loss, and polarization state are reduced to 2%-3% by the ISCM. Furthermore, the method performs ideally under dynamic modulation of the sensor. In addition, it can be applied against the inconsistent fluctuations between signals and is suitable for F-P sensors with single or multiple cavities. Owing to the high efficiency, real-time ability, and no moving parts advantage, the proposed method provides an excellent candidate for improving the accuracy and stability of F-P interrogation systems.

High-sensitive MEMS Fabry-Perot pressure sensor employing an internal-external cavity Vernier effect.

In this paper, a high sensitivity pressure sensor employing an internal-external cavity Vernier effect is innovatively achieved with the microelectromechanical systems (MEMS) Fabry-Perot (FP) interferometer. The sensor consists of silicon cavity, vacuum cavity, and silicon-vacuum hybrid cavity, which is fabricated by direct bonding a silicon diaphragm with an etched cylindrical cavity and a silicon substrate. By rationally designing the optical lengths of the silicon cavity and silicon-vacuum hybrid cavity to match, the internal-external cavity Vernier effect will be generated. The proposed cascaded MEMS FP structure exhibits a pressure sensitivity of -1.028 nm/kPa by tracking the envelope evolution of the reflection spectrum, which is 58 times that of the silicon-vacuum hybrid cavity. What's more, it owns a minimal temperature sensitivity of 0.041 nm/°C for the envelope spectrum. The MEMS FP sensor based on internal-external cavity Vernier effect as the promising candidate provides an essential guideline for high sensitivity pressure measurement under the characteristic of short FP sensing cavity length, which demonstrates the value to the research community.

Bifunctional Magnetic Fe3O4@Cu2O@TiO2 Nanosphere-Mediated Dual-Mode Assay of PTP1B Activity Based on Photocurrent Polarity Switching and Nanozyme-Engineered Biocatalytic Precipitation Strategies.

Dysregulation of protein phosphatases is associated with the progression of various human diseases and cancers. Herein, a photoelectrochemical (PEC)-quartz crystal microbalance (QCM) dual-mode sensing platform was developed for protein tyrosine phosphatase 1B (PTP1B) activity assay based on bifunctional magnetic Fe3O4@Cu2O@TiO2 nanosphere-mediated PEC photocurrent polarity switching and QCM signal amplification strategies. The PTP1B-specific phosphopeptide (P-peptide) with a cysteine end was designed and immobilized onto the QCM Au chip via the Au-S bond. Subsequently, the Fe3O4@Cu2O@TiO2 nanosphere was connected to the P-peptide via the specific interaction between the phosphate group on the P-peptide and TiO2. After incubation with PTP1B, the dephosphorylation of the P-peptide occurred, causing some Fe3O4@Cu2O@TiO2 nanospheres to be released from the chip surface. The released magnetic Fe3O4@Cu2O@TiO2 nanospheres (labeled as R-Fe3O4@Cu2O@TiO2) were quickly separated via magnetic separation technology and attached to the Bi2S3-decorated magnetic indium-tin oxide (Bi2S3/MITO) electrode by magnetic force, inducing the switch of the photocurrent polarity of the electrode from anodic current (the Bi2S3/MITO electrode) to cathodic current (the R-Fe3O4@Cu2O@TiO2/Bi2S3/MITO electrode). Also, the nondephosphorylated P-peptide linked Fe3O4@Cu2O@TiO2 nanospheres as nanozymes with horseradish peroxidase activity to catalyze the formation of precipitation on the surface of the Au chip, leading to a frequency change of the QCM. Thus, the proposed PEC-QCM dual-mode sensing platform achieved accurate and reliable assay of PTP1B activity because of the different mechanisms and independent signal transductions. In addition, this dual-mode sensing platform can be easily extended for other protein phosphatase activity analysis and shows great potential in the early diagnosis of the protein phosphatase-related diseases and the protein phosphatase-targeted drug discovery.

Tensile-Strained Palladium Nanosheets for Synthetic Catalytic Therapy and Phototherapy.

Palladium nanosheets (Pd NSs) are well-investigated photothermal therapy agents, but their catalytic potential for tumor therapy has been underexplored owing to the inactive dominant (111) facets. Herein, lattice tensile strain is introduced by surface reconstruction to activate the inert surface, endowing the strained Pd NSs (SPd NSs) with photodynamic, catalase-like, and peroxidase-like properties. Tensile strain promoting the photodynamic and enzyme-like activities is revealed by density functional theory calculations. Compared with Pd NSs, SPd NSs exhibit lower photothermal effect, but approximately five times higher tumor inhibition rate. This work calls for further study to activate nanomaterials by strain engineering and surface reconstruction for catalytic therapy of tumors.

Interfacial Characteristics of 6061/AZ31B Composites in Multi-Pass Rolling.

An Al 6061/Mg AZ31B composite plate with good bonding and excellent comprehensive mechanical properties was prepared through solid-liquid cast-rolling bonding (SLCRB). The microstructure evolution and mechanical behavior of Al/Mg composite plates under different rolling passes were studied. The results showed that with the increase of rolling passes, the bonding layer of the composite plate was crushed, and the base material on both sides of the substrate gradually grew towards the broken part of the bonding layer. The microstructure on both sides of the substrate extended along the rolling direction and was dynamically recrystallized to a certain extent. In the Mg substrate, because the preheating temperature was higher than its recrystallization temperature, with the increase of rolling passes, the grains in Mg substrate were crystallized. When the rolling passes reached the fourth pass, complete recrystallization basically took place in the Mg substrate. With the change of the internal structure and bonding layer on both sides of the substrate, the mechanical properties of the composite plate can be improved gradually. The tensile strength increased from 136 MPa before rolling to 190 MPa at the fourth pass, and the shear strength increased from 74 MPa to 98 MPa, with growth rates of about 40% and 32%, respectively. The elongation of the composite plate decreased from 6.3% to 5.4%, a decrease of about 1%.

A novel use for Levey-Jennings charts in prenatal molecular diagnosis.

BACKGROUND: The goal of this study was to determine whether Levey-Jennings charts, which are widely used in clinical laboratories, can be used to create standardized internal quality controls (IQCs) for prenatal molecular diagnosis. METHODS: Aneuploid amniocyte lines with trisomy 13, 21, and 18, and 47,XXY were established by transfection with SV40LTag-pcDNA3.1(-)and combined at different ratios to generate aneuploidy chimeric quality-control cell mixtures A to H. These quality-control cells were then used to calculate the [Formula: see text], [Formula: see text] ±1 standard deviation (SD), [Formula: see text] ±2 SD, and [Formula: see text] ±3 SD values to develop standardized IQCs for methods used for the prenatal diagnosis of aneuploidies such as FISH. RESULTS: Methods for constructing aneuploid amniocyte lines were developed and a set of quality-control cells (A-H) were prepared. The [Formula: see text] ±1 SD, [Formula: see text] ±2 SD, and [Formula: see text] ±3 SD values of these quality-control cells for trisomy 13 and 21 were 10.2 ± 1.7, 10.2 ± 3.4, and 10.2 ± 5.1, and 90.3 ± 2.3, 90.3 ± 4.6, and 90.3 ± 6.9, respectively. Based on the values and Levey-Jennings charts, a set of standardized IQCs for prenatal diagnosis such as FISH were established. CONCLUSIONS: This method resolves the problems of a shortage of quality-control materials and a lack of quality-control charts in prenatal molecular diagnosis such as NIPT, NGS, aCGH/SNP, PCR, and FISH. Levey-Jennings chart-based IQCs for prenatal diagnosis such as FISH can be used to easily monitor whether IQC results are within acceptable limits, and then infer whether the diagnostic results for clinical samples are reliable. We expect that this standardized IQC will be useful for a wide range of molecular diagnostic laboratories.

A novel cluster-tube self-adaptive robot hand.

This paper proposes a novel cluster-tube self-adaptive robot hand (CTSA Hand). The CTSA Hand consists of a base, a motor, a transmission mechanism, multiple elastic tendons, and a group of sliding-tube assemblies. Each sliding-tube assembly is composed of a sliding tube, a guide rod, two springs and a hinge. When the hand grasping an object, the object pushes some sliding tubes to different positions according to the surface shape of the object, the motor pulls the tendons tight to cluster tubes. The CTSA Hand can realize self-adaptive grasping of objects of different sizes and shapes. The CTSA Hand can grasp multiple objects simultaneously because the grasping of the hand acts as many grippers in different directions and heights. The grasping forces of the hand are adjusted by a closed-loop control system with potentiometer. Experimental results show that the CTSA Hand has the features of highly self-adaption and large grasping forces when grasping various objects.