Stimulus-Responsive Amino Acids Behind In Situ Assembled Bioactive Peptide Materials.

In situ self-assembly of peptides into well-defined nanostructures represents one of versatile strategies for creation of bioactive materials within living cells with great potential in disease diagnosis and treatment. The intimate relationship between amino acid sequences and the assembling propensity of peptides has been thoroughly elucidated over the past few decades. This has inspired development of various controllable self-assembling peptide systems based on stimuli-responsive naturally occurring or non-canonical amino acids, including redox-, pH-, photo-, enzyme-responsive amino acids. This review attempts to summarize the recent progress achieved in manipulating in situ self-assembly of peptides by controllable reactions occurring to amino acids. We will highlight the systems containing non-canonical amino acids developed in our laboratory during the past few years, primarily including acid/enzyme-responsive 4-aminoproline, redox-responsive (seleno)methionine, and enzyme-responsive 2-nitroimidazolyl alanine. Utilization of the stimuli-responsive assembling systems in creation of bioactive materials will be specifically introduced to emphasize their advantages for addressing the concerns lying in disease theranostics. Eventually, we will provide the perspectives for the further development of stimulus-responsive amino acids and thereby demonstrating their great potential in development of next-generation biomaterials.

Noncanonical Amino Acids for Hypoxia-Responsive Peptide Self-Assembly and Fluorescence.

Design of endogenous stimuli-responsive amino acids allows for precisely modulating proteins or peptides under a biological microenvironment and thereby regulating their performance. Herein we report a noncanonical amino acid 2-nitroimidazol-1-yl alanine and explore its functions in creation of the nitroreductase (NTR)-responsive peptide-based supramolecular probes for efficient hypoxia imaging. On the basis of the reduction potential of the nitroimidazole unit, the amino acid was synthesized via the Mitsunobu reaction between 2-nitroimidazole and a serine derivate. We elucidated the relationship between the NTR-responsiveness of the amino acid and the structural feature of peptides involving a series of peptides. This eventually facilitates development of aromatic peptides undergoing NTR-responsive self-assembly by rationally optimizing the sequences. Due to the intrinsic role of 2-nitroimidazole in the fluorescence quench, we created a morphology-transformable supramolecular probe for imaging hypoxic tumor cells based on NTR reduction. We found that the resulting supramolecular probes penetrated into solid tumors, thus allowing for efficient fluorescence imaging of tumor cells in hypoxic regions. Our findings demonstrate development of a readily synthesized and versatile amino acid with exemplified properties in creating fluorescent peptide nanostructures responsive to a biological microenvironment, thus providing a powerful toolkit for synthetic biology and development of novel biomaterials.

Factor structure, measurement invariance, and psychometric properties of the Posttraumatic Cognitions Inventory (PTCI) and its brief version (PTCI-9) in Chinese adolescents and adults.

The Posttraumatic Cognitions Inventory (PTCI) is a widely used self-report tool to assess negative posttraumatic cognitions about self, world, and self-blame, but the factor structure remains controversial. Recently, a brief version of the PTCI with nine items (PTCI-9) loading onto three factors has been developed, and an excellent model fit was obtained. In this study, we examined the psychometric properties of the PTCI and PTCI-9 in a large sample of trauma-exposed Chinese adolescents (n = 1,451; mean age = 13.67 years, SD = 1.24) and adults (n = 924; mean age = 39.6 years, SD = 5.43). Confirmatory factor analysis indicated an acceptable model fit for the original PTCI but a better model fit for the PTCI-9. Furthermore, the configural, metric, and scalar invariances of the PTCI-9 were supported across age groups (adolescent and adult), gender (male and female), trauma exposure (direct and indirect), and types of traumatic events (interpersonal and noninterpersonal). The PTCI and PTCI-9 and their subscale scores showed adequate internal consistency reliability in adolescent and adult samples. The PTCI-9 also demonstrated good convergent validity, as demonstrated by statistically significant correlations with PTSD, depression, anxiety, and life satisfaction. Overall, the present study supports the Chinese PTCI and PTCI-9 as valid measures of negative cognitions in both adolescents and adults and makes meaningful comparisons of negative cognitions across gender, trauma exposure, and types of traumatic events. Notably, as a brief and valid tool, the PTCI-9 is suggested to be used in survey and longitudinal studies for adolescents and adults. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Correlation between lipoprotein-associated phospholipase A2 and poststroke mild cognitive impairment.

OBJECTIVES: This study aimed to investigate the correlation between serum lipoprotein-associated phospholipase A2 (Lp-PLA2) and poststroke mild cognitive impairment (PSMCI). METHODS: The patients included in the study were divided into PSMCI (68 cases) and cognitively normal (CN) (218 cases) groups and followed up for six months. Demographic and clinical data were collected. A logistic regression analysis was performed to determine whether Lp-PLA2 is an independent risk factor for PSMCI. Spearman's correlation analysis was used to examine the correlation between Lp-PLA2 levels and Montreal Cognitive Assessment (MoCA) scores. A receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic threshold value of Lp-PLA2 for PSMCI. RESULTS: Serum Lp-PLA2 levels were significantly higher in the PSMCI group than in the CN group. The logistic regression analysis showed that Lp-PLA2 was an independent risk factor for PSMCI (OR = 1.05, 95% CI = 1.03-1.07). Spearman's correlation analysis revealed a significant correlation between the Lp-PLA2 levels and MoCA scores (R = -0.49). The area under the ROC curve for Lp-PLA2 was 0.849, and the threshold value for PSMCI occurrence was 236.8 ng/ml. CONCLUSIONS: Elevated serum Lp-PLA2 is an independent risk factor for PSMCI and may serve as a potential biomarker for PSMCI.

Prevalence of antibiotic resistance genes, heavy metal, and bacterial community composition in sea sediments influenced by Eriocheir sinensis breeding aquaculture.

Eriocheir sinensis is the main aquaculture species in China. With the continuous expansion of the aquaculture scale, the demand for E. sinensis seedlings was also increased. The water used in breeding has well-nourished and its discharge into the sea posed significant risks. This study sampled the wastewater discharge points of the E. sinensis seedlings in Sheyang County, Jiangsu Province, and the areas far from the discharge points that were not affected in March and May 2023, respectively. A large number of antibiotic resistance genes (ARGs) were found in the sediment of the wastewater discharge area, and the highest ARG was sulfonamide ARG-sul1 using qPCR analysis, while ARGs were almost undetectable in the areas not affected by wastewater discharge. The 16S rRNA sequence analysis results showed that the main bacterial phyla at the wastewater discharge point were Bacteroidetes, Proteobacteria, and Thermodesulfobacteria. In the control point, the main bacterial phyla were Proteobacteria, Chlorobacterium, and Thermodesulfobacteria. There were significant differences in the composition of microbial communities between the two points, and the samples at the wastewater discharge point were more clustered and had higher similarity. The correlation network and redundancy analysis indicated that the phyla Bacteroidetes, Firmicutes, and Proteobacteria at the wastewater discharge points were positively correlated with most ARGs. The wastewater discharge had no effect on heavy metals from the two points. This study sets a foundation for future research by identifying key microbial taxa as potential ARG carriers and examining the interactions between microbial communities, ARGs, and heavy metals.

Pushing the Electrochemical Performance Limits of Polypyrrole Toward Stable Microelectronic Devices.

Conducting polymers have achieved remarkable attentions owing to their exclusive characteristics, for instance, electrical conductivity, high ionic conductivity, visual transparency, and mechanical tractability. Surface and nanostructure engineering of conjugated conducting polymers offers an exceptional pathway to facilitate their implementation in a variety of scientific claims, comprising energy storage and production devices, flexible and wearable optoelectronic devices. A two-step tactic to assemble high-performance polypyrrole (PPy)-based microsupercapacitor (MSC) is utilized by transforming the current collectors to suppress structural pulverization and increase the adhesion of PPy, and then electrochemical co-deposition of PPy-CNT nanostructures on rGO@Au current collectors is performed. The resulting fine patterned MSC conveyed a high areal capacitance of 65.9 mF cm-2 (at a current density of 0.1 mA cm-2), an exceptional cycling performance of retaining 79% capacitance after 10,000 charge/discharge cycles at 5 mA cm-2. Benefiting from the intermediate graphene, current collector free PPy-CNT@rGO flexible MSC is produced by a facile transfer method on a flexible substrate, which delivered an areal capacitance of 70.25 mF cm-2 at 0.1 mA cm-2 and retained 46% of the initial capacitance at a current density of 1.0 mA cm-2. The flexible MSC is utilized as a skin compatible capacitive micro-strain sensor with excellent electromechanochemical characteristics.

Engineering Vacancies at the 2D Nanocrystals for Robust Bifunctional Electrocatalysts.

Hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) through water decomposition are feasible methods to produce green and clean energy. Herein, we report a facile two-step strategy for the preparation of non-noble metal defect-rich nanosheets by an electrochemical process at room temperature. First-principle calculations are used to study the bifunctional catalytic reaction mechanism of defect engineering in transition-metal dichalcogenides (TMDs); from the first-principle calculations, we predicted that the rich S vacancies on the nanosheet promoted electron transfer and reduced the energy barrier of electrocatalysis. As a substantiation, we conducted HER/OER electrochemical characterizations and found that the defect-rich atomic-thick tantalum sulfide is a kind of dual-function electrocatalyst with enhanced comprehensive properties of Tafel slope (39 mV/dec for HER, 38 mV/dec for OER) and low overpotential (0.099 V for HER, 0.153 V for OER) in acidic and alkaline environments, respectively. Likewise, the defect-rich catalysts exhibit high stability in acidic and alkaline solutions, which have potential applications as electrocatalysts for the large-scale production of hydrogen and oxygen.

Interface Capture Effect Printing Atomic-Thick 2D Semiconductor Thin Films.

2D semiconductor crystals offer the opportunity to further extend Moore's law to the atomic scale. For practical and low-cost electronic applications, directly printing devices on substrates is advantageous compared to conventional microfabrication techniques that utilize expensive photolithography, etching, and vacuum-metallization processes. However, the currently printed 2D transistors are plagued by unsatisfactory electrical performance, thick semiconductor layers, and low device density. Herein, a facile and scalable 2D semiconductor printing strategy is demonstrated utilizing the interface capture effect and hyperdispersed 2D nanosheet ink to fabricate high-quality and atomic-thick semiconductor thin-film arrays without additional surfactants. Printed robust thin-film transistors using 2D semiconductors (e.g., MoS2 ) and 2D conductive electrodes (e.g., graphene) exhibit high electrical performance, including a carrier mobility of up to 6.7 cm2 V-1 s-1 and an on/off ratio of 2 × 106 at 25 °C. As a proof of concept, 2D transistors are printed with a density of ≈47 000 devices per square centimeter. In addition, this method can be applied to many other 2D materials, such as NbSe2 , Bi2 Se3 , and black phosphorus, for printing diverse high-quality thin films. Thus, the strategy of printable 2D thin-film transistors provides a scalable pathway for the facile manufacturing of high-performance electronics at an affordable cost.