A Review of Dynamic Mechanical Behavior and the Constitutive Models of Aluminum Matrix Composites.

Aluminum matrix composites (AMMCs) have demonstrated substantial potential in the realm of armor protection due to their favorable properties, including low density, high specific stiffness, and high specific strength. These composites are widely employed as structural components and frequently encounter high strain rate loading conditions, including explosions and penetrations during service. And it is crucial to note that under dynamic conditions, these composites exhibit distinct mechanical properties and failure mechanisms compared to static conditions. Therefore, a thorough investigation into the dynamic mechanical behavior of aluminum matrix composites and precise constitutive equations are imperative to advance their application in armor protection. This review aims to explore the mechanical properties, strengthening the mechanism and deformation damage mechanism of AMMCs under high strain rate. To facilitate a comprehensive understanding, various constitutive equations are explored, including phenomenological constitutive equations, those with physical significance, and those based on artificial neural networks. This article provides a critical review of the reported work in this field, aiming to analyze the main challenges and future development directions of aluminum matrix composites in the field of protection.

Cadmium-induced global DNA hypermethylation promoting mitochondrial dynamics dysregulation in hippocampal neurons.

Environmental cadmium exposure during pregnancy or adolescence can cause neurodevelopmental toxicity, lead to neurological impairment, and reduce cognitive abilities, such as learning and memory. However, the mechanisms by which cadmium causes neurodevelopmental toxicity and cognitive impairment are still not fully elucidated. This study used hippocampal neurons cultured in vitro to observe the impact of cadmium exposure on mitochondrial dynamics and apoptosis. Exposure to 5 µM cadmium causes degradation of hippocampal neuron cell bodies and axons, morphological destruction, low cell viability, and apoptosis increase. Cadmium exposure upregulates the expression of mitochondrial fission proteins Drp1 and Fis1, reduces the expression of mitochondrial fusion-related proteins MFN1, MFN2, and OPA1, as well as reduces the expression of PGC-1a. Mitochondrial morphology detection demonstrated that cadmium exposure changes the morphological structure of mitochondria in hippocampal neurons, increasing the number of punctate and granular mitochondria, reducing the number of tubular and reticular mitochondria, decreasing mitochondrial mass, dissipating mitochondrial membrane potential (ΔΨm), and reducing adenosine triphosphate (ATP) production. Cadmium exposure increases the global methylation level of the genome and upregulates the expression of DNMT1 and DNMT3α in hippocampal neurons. 5-Aza-CdR reduces cadmium-induced genome methylation levels in hippocampal neurons, increases the number of tubular and reticular mitochondria, and promotes cell viability. In conclusion, cadmium regulates the expression of mitochondrial dynamics-related proteins by increasing hippocampal neuron genome methylation, changing mitochondrial morphology and function, and exerting neurotoxic effects.

Influence of Interface on Mechanical Behavior of Al-B4C/Al Laminated Composites under Quasi-Static and Impact Loading.

In this study, Al-B4C/Al laminated composites with high interlayer bonding strength were fabricated by integrated hot-pressed sintering accompanied with hot rolling. The mechanical properties and interface behavior of the Al-B4C/Al laminated composites were investigated under quasi-static and impact loading. The results show that the Al-B4C/Al laminated composites obtain a high interface bonding strength, because no interlayer delamination occurs even after fractures under quasi-static and impact loads. The Al-B4C/Al laminated composites exhibit a better comprehensive mechanical performance, and the fracture can be delayed due to the high bonding strength interface. Moreover, laminated composites can absorb more impact energy than the monolithic material under impact loading due to the stress transition and relaxation.

Using Bayesian networks with tabu algorithm to explore factors related to chronic kidney disease with mental illness: A cross-sectional study.

While Bayesian networks (BNs) offer a promising approach to discussing factors related to many diseases, little attention has been poured into chronic kidney disease with mental illness (KDMI) using BNs. This study aimed to explore the complex network relationships between KDMI and its related factors and to apply Bayesian reasoning for KDMI, providing a scientific reference for its prevention and treatment. Data was downloaded from the online open database of CHARLS 2018, a population-based longitudinal survey. Missing values were first imputed using Random Forest, followed by propensity score matching (PSM) for class balancing regarding KDMI. Elastic Net was then employed for variable selection from 18 variables. Afterwards, the remaining variables were included in BNs model construction. Structural learning of BNs was achieved using tabu algorithm and the parameter learning was conducted using maximum likelihood estimation. After PSM, 427 non-KDMI cases and 427 KDMI cases were included in this study. Elastic Net identified 11 variables significantly associated with KDMI. The BNs model comprised 12 nodes and 24 directed edges. The results suggested that diabetes, physical activity, education levels, sleep duration, social activity, self-report on health and asset were directly related factors for KDMI, whereas sex, age, residence and Internet access represented indirect factors for KDMI. BN model not only allows for the exploration of complex network relationships between related factors and KDMI, but also could enable KDMI risk prediction through Bayesian reasoning. This study suggests that BNs model holds great prospects in risk factor detection for KDMI.

A Novel Multi-Scale Ceramic-Based Array (SiCb+B4Cp)/7075Al as Promising Materials for Armor Structure.

Ceramic panel collapse will easily lead to the failure of traditional targets. One strategy to solve this problem is to use separate ceramic units as armor panels. Based on this idea, we propose an aluminum matrix composite using pressure infiltration, containing an array of ceramic balls, the reinforcement of which consists of centimeter-scale SiC balls and micron-scale B4C particles. Three different array layouts were designed and fabricated: compact balls in the front panel (F-C), non-compact balls in the front panel (F-NC), and compact balls inside the target (I-C). The penetration resistance properties were tested using a 12.7 mm armor-piercing incendiary (API). The results show that there are no significant internal defects, and the ceramic balls are well-bonded with the matrix composite. The F-NC structure behaves the best penetration resistance with minimal overall damage; the I-C structure has a large area of spalling and the most serious damage. Finite element simulation reveals that the ceramic balls play a major role in projectile erosion; in the non-compact structure, the composite materials between the ceramic balls can effectively disperse the stress, thereby avoiding the damage caused by direct contact between ceramic balls and improving the efficiency of ceramic ball erosion projectiles. Furthermore, it is essential to have a certain thickness of supporting materials to prevent spalling failure caused by stress wave transmission during penetration. This multi-scale composite exhibits excellent ballistic performance, providing valuable insights for developing anti-penetration composite armor in future applications.

Embedded Ultrasonic Inspection on the Mechanical Properties of Cold Region Ice under Varying Temperatures.

The mechanical properties of ice in cold regions are significantly affected by the variation in temperature. The existing methods to determine ice properties commonly rely on one-off and destructive compression and strength experiments, which are unable to acquire the varying properties of ice due to temperature variations. To this end, an embedded ultrasonic system is proposed to inspect the mechanical properties of ice in an online and real-time mode. With this system, ultrasonic experiments are conducted to testify to the validity of the system in continuously inspecting the mechanical properties of ice and, in particular, to verify its capabilities to obtain ice properties for various temperature conditions. As an extension of the experiment, an associated refined numerical model is elaborated by mimicking the number, size, and agglomeration of bubbles using a stochastic distribution. This system can continuously record the wave propagation velocity in the ice, giving rise to ice properties through the intrinsic mechanics relationship. In addition, this model facilitates having insights into the effect of properties, e.g., porosity, on ice properties. The proposed embedded ultrasonic system largely outperforms the existing methods to obtain ice properties, holding promise for developing online and real-time monitoring techniques to assess the ice condition closely related to structures in cold regions.

Establishment and validation of a predictive model of recurrence in primary hepatocellular carcinoma after resection.

Background: In recent years, nomogram prediction models have been widely used to evaluate the prognosis of various diseases. However, studies in primary hepatocellular carcinoma (HCC) are limited. This study sought to explore the risk factors of recurrence of patients with primary HCC after surgical resection and establish a nomogram prediction model. Methods: The data of 424 patients with primary HCC who had been admitted to the Wuhan Third Hospital were retrospectively collected. The patients were followed-up for 5 years after surgery. The patients were divided into the recurrence group (n=189) and control group (n=235) according to whether the cancer recurred after surgery. The differences in the clinical characteristics between the two groups were analyzed. The risk factors of recurrence after surgical resection of primary HCC were also analyzed, and a prediction model was then established using R4.0.3 statistical software. Results: There were significant statistical differences between the two groups in terms of the tumor size, systemic immune-inflammation (SII) index, the number of lesions, tumor differentiation degree, ascites, vascular invasion, and portal vein tumor thrombus (P<0.05). The multivariate regression analysis showed that multiple foci, poorly differentiated tumors, ascites, vascular invasion, and portal vein tumor thrombus were risk factors for the recurrence of primary HCC in patients after surgical resection (P<0.05). The data set was randomly divided into a training set and verification set. The sample size of the training set was 297, and the sample size of the verification set was 127. The area under the receiver operating characteristic (ROC) curve of the training set was 0.866 [95% confidence interval (CI): 0.824-0.907], and the area under the ROC curve of the validation set was 0.812 (95% CI: 0.734-0.890). The Hosmer-Lemeshow Goodness-of-Fit Test was used to test the model with the validation set (χ2=11.243, P=0.188), which indicated that the model had high value in predicting the recurrence of primary HCC after surgical resection. Conclusions: This model had high value in predicting the recurrence of primary HCC in patients after surgical resection. This model could assist clinicians to assess the prognosis of patients. Intensive treatment for high-risk patients might improve the prognosis of patients.

Using Bayesian networks with Tabu-search algorithm to explore risk factors for hyperhomocysteinemia.

Hyperhomocysteinemia (HHcy) is a condition closely associated with cardiovascular and cerebrovascular diseases. Detecting its risk factors and taking some relevant interventions still represent the top priority to lower its prevalence. Yet, in discussing risk factors, Logistic regression model is usually adopted but accompanied by some defects. In this study, a Tabu Search-based BNs was first constructed for HHcy and its risk factors, and the conditional probability between nodes was calculated using Maximum Likelihood Estimation. Besides, we tried to compare its performance with Hill Climbing-based BNs and Logistic regression model in risk factor detection and discuss its prospect in clinical practice. Our study found that Age, sex, α1-microgloblobumin to creatinine ratio, fasting plasma glucose, diet and systolic blood pressure represent direct risk factors for HHcy, and smoking, glycosylated hemoglobin and BMI constitute indirect risk factors for HHcy. Besides, the performance of Tabu Search-based BNs is better than Hill Climbing-based BNs. Accordingly, BNs with Tabu Search algorithm could be a supplement for Logistic regression, allowing for exploring the complex network relationship and the overall linkage between HHcy and its risk factors. Besides, Bayesian reasoning allows for risk prediction of HHcy, which is more reasonable in clinical practice and thus should be promoted.

Encapsulating Organic Dyes in Metal-Organic Frameworks for Color-Tunable and High-Efficiency White-Light-Emitting Properties.

The design of white-light phosphor is highly desirable for practical applications in SSL (solid-state lighting) and its related fields. Dye-loaded metal-organic frameworks (MOFs) have been widely demonstrated as one type of promising down conversion materials for WLEDs (white-light-emitting diodes), but two issues (dye leakage and inadequate quantum efficiency) require to be addressed before possible applications. Here, a series of single-phase dyes@In-MOF phosphors have been prepared in two different ways: the in-situ process and soaking method. The study of these dyes@In-MOF phosphors confirms the importance of this in-situ process that could effectively increase dye loading and quantum efficiency and greatly decrease dye leakage. As a result, a perfect WLED, fabricated using the in-situ-synthesized (AF/RhB@In-MOF)-3 (AF: Acriflavine; RhB: Rhodamine B) and 450 nm blue LED chip, exhibited a very high quantum yield (QY, up to 42.27%), a high luminous efficacy (LE) of 50.75 lm/W, a high color rendering index (CRI) of 91.2, and nearly identical Commission International ed'Eclairage (CIE) coordinates (0.33,0.31), indicating the potential application of the dye-loaded MOFs with good color quality in smart white LEDs.

Physiological and Molecular Mechanisms of Plant Responses to Copper Stress.

Copper (Cu) is an essential micronutrient for humans, animals, and plants, and it participates in various morphological, physiological, and biochemical processes. Cu is a cofactor for a variety of enzymes, and it plays an important role in photosynthesis, respiration, the antioxidant system, and signal transduction. Many studies have demonstrated the adverse effects of excess Cu on crop germination, growth, photosynthesis, and antioxidant activity. This review summarizes the biological functions of Cu, the toxicity of excess Cu to plant growth and development, the roles of Cu transport proteins and chaperone proteins, and the transport process of Cu in plants, as well as the mechanisms of detoxification and tolerance of Cu in plants. Future research directions are proposed, which provide guidelines for related research.

Prevalence of Non-SARS-CoV-2 Respiratory Pathogens and Co-Infection with SARS-CoV-2 in the Early Stage of COVID-19 Epidemic.

BACKGROUND: This study aims to reflect the prevalence of non-SARS-CoV-2 respiratory pathogens and co-infection with SARS-CoV-2 in the early stage of the COVID-19 epidemic, considering SARS-CoV-2 broke out during influenza season and its symptoms resemble those of influenza. METHODS: A total of 685 nucleic acid samples of respiratory pathogens were collected from 1 November 2019 to 20 January 2020 and were detected by the 13 Respiratory Pathogen Multiplex Detection Kit and Novel Coronavirus (2019-nCoV) Nucleic Acid Diagnostic Kit. RESULTS: In Wuhan, human rhinovirus was the most frequent infectious pathogen in November (31.5%) and human respiratory syncytial virus appeared the most in December and January (37.1%, 8.6%, respectively). Detection of SARS-CoV-2 first appeared from January 1 to January 10. Generally, 115 patients of 616 patients (18.7%) from Wuhan were infected with SARS-CoV-2, and only two children were co-infected with other respiratory pathogens. In Taiyuan, influenza A virus was detected most frequently in December and January (30.3%, 12%, respectively) without infection of SARS-CoV-2. CONCLUSIONS: Some cases diagnosed with influenza before routine nucleic acid testing of SARS-CoV-2 were attributed to COVID-19. Co-infection between SARS-CoV-2 and other non-SARS-CoV-2 respiratory pathogens existed in the early stage of COVID-19 epidemic.

Using Bayesian networks with Max-Min Hill-Climbing algorithm to detect factors related to multimorbidity.

Objectives: Multimorbidity (MMD) is a medical condition that is linked with high prevalence and closely related to many adverse health outcomes and expensive medical costs. The present study aimed to construct Bayesian networks (BNs) with Max-Min Hill-Climbing algorithm (MMHC) algorithm to explore the network relationship between MMD and its related factors. We also aimed to compare the performance of BNs with traditional multivariate logistic regression model. Methods: The data was downloaded from the Online Open Database of CHARLS 2018, a population-based longitudinal survey. In this study, we included 10 variables from data on demographic background, health status and functioning, and lifestyle. Missing value imputation was first performed using Random Forest. Afterward, the variables were included into logistic regression model construction and BNs model construction. The structural learning of BNs was achieved using MMHC algorithm and the parameter learning was conducted using maximum likelihood estimation. Results: Among 19,752 individuals (9,313 men and 10,439 women) aged 64.73 ± 10.32 years, there are 9,129 ones without MMD (46.2%) and 10,623 ones with MMD (53.8%). Logistic regression model suggests that physical activity, sex, age, sleep duration, nap, smoking, and alcohol consumption are associated with MMD (P < 0.05). BNs, by establishing a complicated network relationship, reveals that age, sleep duration, and physical activity have a direct connection with MMD. It also shows that education levels are indirectly connected to MMD through sleep duration and residence is indirectly linked to MMD through sleep duration. Conclusion: BNs could graphically reveal the complex network relationship between MMD and its related factors, outperforming traditional logistic regression model. Besides, BNs allows for risk reasoning for MMD through Bayesian reasoning, which is more consistent with clinical practice and thus holds some application prospects.

Salt Tolerance of Rice Is Enhanced by the SS3 Gene, Which Regulates Ascorbic Acid Synthesis and ROS Scavenging.

Mining the key genes involved in the balance of rice salt tolerance is extremely important for developing salt-tolerant rice varieties. A library of japonica mutants was screened under salinity conditions to identify putative salt stress-responsive genes. We identified a highly salt-sensitive mutant ss3 and used a map-based cloning approach to isolate the gene SS3, which encodes mannose-1-phosphate guanylyltransferase. Under salt treatment, ss3 mutants have decreased ascorbic acid (AsA) content and increased reactive oxygen species (ROS) levels compared with the wild type (WT). Exogenous AsA restored the salt tolerance of ss3 plants, indicating that inhibition of AsA synthesis was an important factor in the salt sensitivity of the mutant. Functional complementation using the WT allele rescued the mutation, and transcription of SS3 was induced by salt stress. Vector SS3p:SS3 was constructed containing the 1086 bp coding sequence of SS3. Under salinity conditions, transgenic seedlings expressing SS3p:SS3 had improved salt tolerance relative to WT, as demonstrated by better growth status, higher chlorophyll content, a lower level of Na+, and a reduced Na+/K+ ratio. Further investigation revealed that several senescence- and autophagy-related genes were expressed at lower levels in salt-stressed transgenic lines compared to WT. These results demonstrate the positive impact of SS3 on salt tolerance in rice through the regulation of AsA synthesis and ROS accumulation, and indicate that SS3 is a valuable target for genetic manipulation.

Self-Assembly of Amphiphilic BODIPY Derivatives on Micropatterned Ionic Liquid Surfaces for Fluorescent Films with Excellent Stability and Sensing Performance.

Fluorescent films have been widely recognized as one of the most powerful tools for trace analyte detection. However, their use has been limited due to the poor photochemical stability of fluorophores at a gas-solid interface and inefficient film mass transfer. Herein, novel fluorescent films were developed through self-assembly of amphiphilic BODIPY derivatives on micropatterned ionic liquid surfaces. Unlike solid-state films, the obtained monolayer films exhibit excellent photochemical stability, similar to that of a solution. Moreover, the interfacial assembly of amphiphilic fluorophores can avoid gas diffusion inside the microdroplets, significantly improving the sensing performance. The 1/1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) monolayer exhibits high sensitivity, high selectivity, and a fast response to detect diethylchlorophosphate (DCP) vapor. The detection limit was 226 ppt, with a response time to DCP of 2.0 s. Importantly, the 1/[BMIM]BF4 monolayer can be reused for at least 50 cycles with no obvious signal fading. This study is expected to benefit the development of new strategies for designing fluorescence sensing films and lay a solid foundation for the fabrication of multifunctional sensing devices with excellent photochemical stability and sensing performance.

Tubastatin A suppresses the proliferation of fibroblasts in epidural fibrosis through phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signalling pathway.

OBJECTIVES: This study was designed to explore the effect of tubastatin A (Tub A) on epidural fibrosis and the underlying mechanism. METHODS: Histone deacetylase 6 (HDAC6)-overexpressed fibroblasts were constructed, and the effect of Tub A on the proliferation of activated fibroblasts was detected by Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine (EdU) and cell cycle assay. Besides, 20 Sprague-Dawley rats were subjected to animal laminectomy model construction and then randomly treated with 4% dimethyl sulfoxide (DMSO) (diluted in 0.9% saline) or Tub A (10 mg/kg/day), separately. The expression of HDAC6 and phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway-related proteins was measured in epidural fibrosis tissues. KEY FINDINGS: HDAC6 was overexpressed in activated fibroblasts and epidural scar tissues of rat models. Cell proliferation was remarkably elevated in HDAC6-overexpressed fibroblasts, which was reflected by cell viability, EdU and flow cytometry-based cell cycle assay, and paralleled with the increased expression of phosphorylated PI3K, AKT and mTOR, which was remarkably reversed following Tub A treatment. 740Y-P activator addition significantly reversed the declined fibroblast proliferation induced by Tub A. The expressions of PI3K/AKT/mTOR pathway-related proteins were also reduced in epidural tissues in rat models with Tub A treatment. CONCLUSION: Tub A could prevent epidural fibrosis formation by inhibiting fibroblast proliferation through mediating PI3K/AKT/mTOR pathway.

Dimethyl Fumarate Ameliorates Nucleus Pulposus Cell Dysfunction through Activating the Nrf2/HO-1 Pathway in Intervertebral Disc Degeneration.

BACKGROUND: Oxidative stress, inflammation, and nucleus pulposus cells (NPCs) apoptosis are involved in pathogenesis of intervertebral disc (IVD) degeneration (IVDD). Dimethyl fumarate (DMF) has been found to effectively depress oxidative stress and inflammation via the Nrf2 pathway. Hence, this project was designed to explore the underlying mechanisms of how DMF protects NPCs from damage by LPS challenge. METHODS AND RESULTS: CCK8 assay and flow cytometry of apoptosis indicated that DMF treatment attenuated LPS-induced NPC damage. Western blot analysis demonstrated that DMF enhanced the expressions of nuclear factor-erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in LPS-challenged NPCs. DMF treatment significantly decreased the accumulation of ROS, downregulated inflammatory cytokines (p-NF-κB, IL-1ß, and TNF-α), and ER stress-associated apoptosis proteins (Bip, calpain-1, caspase-12, caspase-3, and Bax) in LPS-challenged NPCs. The level of antiapoptotic protein Bcl-2 was promoted by DMF treatment in LPS-challenged NPCs. Glutathione (GSH) assay showed that DMF treatment improved reduced to oxidized glutathione ratio in LPS-challenged NPCs. Furthermore, the results of western blot analysis indicated that in LPS-challenged NPCs, DMF treatment ameliorated the elevated levels of matrix degradation enzymes (MMP-13, aggrecanase 1) and type I collagen and the reduced levels of matrix composition (type II collagen and ACAN). However, Nrf2 knockdown abolished these protective effects of DMF. CONCLUSION: Our data suggested that treatment with DMF mitigated LPS-induced oxidative stress, inflammation, and ER stress-associated apoptosis in NPCs via the Nrf2/HO-1 signaling pathway, thus reliving LPS-induced dysfunction of NPCs, which offered a novel potential pharmacological treatment strategy for IVDD.

[Roles of Histidine Kinases and Histidine Phosphatases in Cancer].

Phosphorylation is the most common and important post-translational modification of proteins, which plays an important role in the regulation of cell proliferation, differentiation, development and metabolism, and is closely related to the tumorigenesis and metastasis of cancer. Protein kinases and phosphatases generally regulate protein phosphorylation levels as a pair of opposite acting enzymes. Protein phosphorylation in eukaryotes occurs mainly in serine, threonine, and tyrosine residues, and their roles in tumorigenesis and development have been extensively studied. But the roles on histidine phosphorylation is less known due to the immature mass spectrometry and enrichment techniques. In recent years, with the rapid development of related technologies and the discovery of new histidine phosphatases, researchers have paid more attention to the roles of histidine phosphorylation in tumors. Therefore, we aim to review the roles of histidine kinases and phosphatases in tumor.
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A Novel Electrochemical Aptasensor for the Ultrasensitive Detection of Adenosine Triphosphate Based on DNA-Templated Copolymers.

Adenosine triphosphate (ATP) is a small but significant biological molecule that plays an important role in regulating cellular metabolism processes. Accurate and sensitive analytical techniques for detecting ATP are urgently needed. Herein, a new electrochemical aptasensor was designed in light of DNA-templated copolymers that parallel to the electrode for sensitive gauging of ATP. The ATP aptamer decorated by the electronic medium ferrocene can be regarded as a ″bridge″ connecting two DNA-templated copolymers. When ATP exists, because of the extraordinary binding selectivity of DNA-templated copolymers for target ATP, the rapid electron transfer of ferrocene was beneficial to the sensitive detection of target ATP. Specifically, our parallel DNA copolymers are more stable than upright DNA copolymers and have a faster signal transmission because of the close distance to the electrode; meanwhile, the nonspecific pollution is less. Consequently, the developed novel aptasensor exhibited a wide range of linear response toward ATP that was from 0.1 to 10 000 pM and high selectivity with a detection limit down to 11.5 fM. The electrochemical aptasensor has a broad application prospect in the detection of small biological molecules.

A label-free electrochemical DNA biosensor for kanamycin detection based on diblock DNA with poly-cytosine as a high affinity anchor on graphene oxide.

It is urgent to develop a more simple and sensitive method to detect antibiotic residues considering the harm of antibiotic residues in food to the human body. Herein we designed a label-free electrochemical DNA biosensor for the sensitive detection of kanamycin (KAN) based on diblock DNA with a 15-mer of poly-cytosine (poly-C). The diblock DNA can be immobilized on graphene oxide (GO) due to strong physical adsorption between the 15-mer of poly-C and GO. The aptamer of KAN acted as the other block for rapidly binding the target. It can specifically capture the target, which leads to the change of electrochemical signal. Consequently, the DNA biosensor exhibited high sensitivity and specificity towards KAN, the linear range was from 0.05 pM to 100 nM with a detection limit of 0.0476 pM. The developed DNA biosensor was constructed easily and showed promising applications for the detection of antibiotic residues for food safety.

Self-Assembled Microgels for Sensitive and Low-Fouling Detection of Streptomycin in Complex Media.

In terms of detection of antibiotics within complex media, the nonspecific adsorption is an enormous challenge and antifouling sensing interfaces capable of reducing the nonspecific adsorption from complex biological samples are highly desirable. In this work, a novel antifouling electrochemical immunosensor was explored based on the self-assembly of two kinds of poly( N-isopropylacrylamide) microgels on the surface of graphene oxide for sensitive detection of streptomycin (STR). The microgels modified with glycidyl methacrylate (GMA) and zwitterionic liquid 1-propyl-3-vinylimidazole sulfonate (PVIS) were prepared. The microgels with GMA were used by combining specific recognition of anti-STR. The rapid specific binding of antigen and anti-STR resulted in a decrease of current density to generate electrochemical responsive signals. Zwitterionic liquid-modified microgels were used for antifouling, which can form stronger hydration and show excellent antifouling ability. As a result, we achieved efficient and sensitive detection of STR in the complex sample with evidently resisted nonspecific adsorption effect, the wide linear range toward STR was from 0.05 to 100 ng mL-1, with a detection limit down to 1.7 pg mL-1. The immunosensor based on the surface functionalization of microgels showed promising applications for the detection of antibiotics in complex media.