An Ultrasensitive and Efficient microRNA Nanosensor Empowered by the CRISPR/Cas Confined in a Nanopore.

This work presents a clustered regularly interspaced short palindromic repeat (CRISPR)/Cas-nanopipette nano-electrochemistry (Cas = CRISPR-associated proteins) capable of ultrasensitive microRNA detection. Nanoconfinement of the CRISPR/Cas13a within a nanopipette leads to a high catalytic efficacy of ca. 169 times higher than that in bulk electrolyte, contributing to the amplified electrochemical responses. CRISPR/Cas13a-enabled detection of representative microRNA-25 achieves a low limit of detection down to 10 aM. Practical application of this method is further demonstrated for single-cell and real human serum detection. Its general applicability is validated by addressing microRNA-141 and the SARS-CoV-2 RNA gene fragment. This work introduces a new CRISPR/Cas-empowered nanotechnology for ultrasensitive nano-electrochemistry and bioanalysis.

Single-cell analysis of Crohn's disease: Unveiling heterogeneity and evaluating ustekinumab outcomes.

BACKGROUND: The present study aimed to dissect the cellular complexity of Crohn's disease (CD) using single-cell RNA sequencing, focusing on identifying key cell populations and their transcriptional profiles in inflamed tissue. METHODS: We applied scRNA-sequencing to compare the cellular composition of CD patients with healthy controls, utilizing Seurat for clustering and annotation. Differential gene expression analysis and protein-protein interaction networks were constructed to identify crucial genes and pathways. RESULTS: Our study identified eight distinct cell types in CD, highlighting crucial fibroblast and T cell interactions. The analysis revealed key cellular communications and identified significant genes and pathways involved in the disease's pathology. The role of fibroblasts was underscored by elevated expression in diseased samples, offering insights into disease mechanisms and potential therapeutic targets, including responses to ustekinumab treatment, thus enriching our understanding of CD at a molecular level. CONCLUSIONS: Our findings highlight the complex cellular and molecular interplay in CD, suggesting new biomarkers and therapeutic targets, offering insights into disease mechanisms and treatment implications.

ROS-induced oxidative stress is a major contributor to sperm cryoinjury.

STUDY QUESTION: What is the mechanism behind cryoinjury in human sperm, particularly concerning the interplay between reactive oxygen species (ROS) and autophagy, and how does it subsequently affect sperm fate? SUMMARY ANSWER: The freeze-thaw operation induces oxidative stress by generating abundant ROS, which impairs sperm motility and activates autophagy, ultimately guiding the sperm toward programmed cell death such as apoptosis and necrosis, as well as triggering premature capacitation. WHAT IS KNOWN ALREADY: Both ROS-induced oxidative stress and autophagy are thought to exert an influence on the quality of frozen-thawed sperm. STUDY DESIGN, SIZE, DURATION: Overall, 84 semen specimens were collected from young healthy fertile males, with careful quality evaluation. The specimens were split into three groups to investigate the ROS-induced cryoinjury: normal control without any treatment, sperm treated with 0.5 mM hydrogen peroxide (H2O2) for 1 h, and sperm thawed following cryopreservation. Samples from 48 individuals underwent computer-assisted human sperm analysis (CASA) to evaluate sperm quality in response to the treatments. Semen samples from three donors were analyzed for changes in the sperm proteome after H2O2 treatment, and another set of samples from three donors were analyzed for changes following the freeze-thaw process. The other 30 samples were used for fluorescence-staining and western blotting. PARTICIPANTS/MATERIALS, SETTING, METHODS: Sperm motility parameters, including progressive motility (PR %) and total motility (PR + NP %), were evaluated using the CASA system on a minimum of 200 spermatozoa. The proteomic profiles were determined with label-free mass spectrometry (MS/MS) and protein identification was performed via ion search against the NCBI human database. Subsequently, comprehensive bioinformatics was applied to detect significant proteomic changes and functional enrichment. Fluorescence-staining and western blot analyses were also conducted to confirm the proteomic changes on selected key proteins. The ROS level was measured using 2',7'-dichlorodihydrofluorescein diacetate labeling and the abundance of bioactive mitochondria was determined by evaluating the inner mitochondrial membrane potential (MMP) level. Molecular behaviors of sequestosome-1 (p62 or SQSTM1) and microtubule-associated proteins 1A/1B light chain 3 (LC3) were monitored to evaluate the state of apoptosis in human sperm. Fluorescent probes oxazole yellow (YO-PRO-1) and propidium iodide (PI) were utilized to monitor programmed cell death, namely apoptosis and necrosis. Additionally, gradient concentrations of antioxidant coenzyme Q10 (CoQ10) were introduced to suppress ROS impacts on sperm. MAIN RESULTS AND THE ROLE OF CHANCE: The CASA analysis revealed a significant decrease in sperm motility for both the H2O2-treatment and freeze-thaw groups. Fluorescence staining showed that high ROS levels were produced in the treated sperm and the MMPs were largely reduced. The introduction of CoQ10 at concentrations of 20 and 30 µM resulted in a significant rescue of progressive motility (P < 0.05). The result suggested that excessive ROS could be the major cause of sperm motility impairment, likely by damaging mitochondrial energy generation. Autophagy was significantly activated in sperm when they were under oxidative stress, as evidenced by the upregulation of p62 and the increased conversion of LC3 as well as the upregulation of several autophagy-related proteins, such as charged multivesicular body protein 2a, mitochondrial import receptor subunit TOM22 homolog, and WD repeat domain phosphoinositide-interacting protein 2. Additionally, fluorescent staining indicated the occurrence of apoptosis and necrosis in both H2O2-treated sperm and post-thaw sperm. The cell death process can be suppressed when CoQ10 is introduced, which consolidates the view that ROS could be the major contributor to sperm cryoinjury. The freeze-thaw process could also initiate sperm premature capacitation, demonstrated by the prominent increase in tyrosine phosphorylated proteins, verified with anti-phosphotyrosine antibody and immunofluorescence assays. The upregulation of capacitation-related proteins, such as hyaluronidase 3 and Folate receptor alpha, supported this finding. LARGE SCALE DATA: The data underlying this article are available in the article and its online supplementary material. LIMITATIONS, REASONS FOR CAUTION: The semen samples were obtained exclusively from young, healthy, and fertile males with progressive motility exceeding 60%, which might overemphasize the positive effects while possibly neglecting the negative impacts of cryoinjury. Additionally, the H2O2 treatment conditions in this study may not precisely mimic the oxidative stress experienced by sperm after thawing from cryopreservation, potentially resulting in the omission of certain molecular alterations. WIDER IMPLICATIONS OF THE FINDINGS: This study provides substantial proteomic data for a comprehensive and deeper understanding of the impact of cryopreservation on sperm quality. It will facilitate the design of optimal protocols for utilizing cryopreserved sperm to improve applications, such as ART, and help resolve various adverse situations caused by chemotherapy, radiotherapy, and surgery. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by grants from the Major Innovation Project of Research Institute of National Health Commission (#2022GJZD01-3) and the National Key R&D Program of China (#2018YFC1003600). All authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.

Dynamic changes of phenotype and function of natural killer cells in peripheral blood before and after thermal ablation of hepatitis B associated hepatocellular carcinoma and their correlation with tumor recurrence.

BACKGROUND: Thermal therapy induces an immune response in patients with hepatocellular carcinoma (HCC), but the dynamic characteristics of the natural killer (NK) cell immune response post-thermal ablation remain unclear. We conducted a prospective longitudinal cohort study to observe the dynamic changes of phenotype and function of NK cells in peripheral blood before and after thermal ablation of hepatitis B-associated HCC and their correlation with tumor recurrence. METHODS: Fifty-six patients clinically and pathologically confirmed with hepatitis B-associated HCC were selected for thermal ablation. Peripheral blood was collected on day 0, day 7, and month 1. NK cell subsets, receptors, and killing function were detected by flow cytometry, and the LDH levels were examined. Overall recurrence and associated variables were estimated using Kaplan-Meier, log-rank, and Cox proportional-hazards analyses. RESULTS: The frequency of CD3-CD56+ cells was increased on day 7 (P < 0.01) without significant differences between D0 and M1. NKG2D, NKp44, NKp30, CD159a, and CD158a expression was increased on M1 (all P < 0.05). The granzyme B and IFN-γ expression in NK cells were higher on M1 vs. D0 (P < 0.05). On day 7, the NK cell lysis activity of the target K562 cells was increased (P < 0.01) but decreased on M1 (P < 0.05). Survival analysis showed that CD158a expression and IFN-γ and perforin release on day 0 were associated with the risk of HCC recurrence. Cox regression analysis showed that the expression changes in CD56, NKp46, granzyme B, and perforin (D7-D0) induced by thermal ablation were associated with recurrence-free survival (RFS) of patients with HCC. CONCLUSION: Thermal ablation increased the frequency and function of CD3-CD56+ NK cells in the peripheral blood of patients with HCC. These cells tended to be more differentiated and activated. Notably, expression levels of NK cell receptors NKp46, perforin, and granzyme B were associated with RFS.

Multiverruca sinensis gen. nov., sp. nov., a thermotolerant fungus isolated from soil in China.

During a survey of thermotolerant fungi in China, three isolates were obtained from soil samples. Phylogenetic analysis of a combined internal transcribed spacer and large subunit dataset showed that these isolates belong to the same species, which form a well-separated lineage distinct from the other genera in Latoruaceae. Morphologically, the isolates are characterized by having globose and smooth conidiogenous cells, verruculose mycelium and cymbiform conidia. Combining the phylogenetic analyses and morphological characteristics, Multiverruca gen. nov. is proposed and introduced to accommodate a single new species, Multiverruca sinensis sp. nov. Detailed descriptions, illustrations and notes are provided for the new genus and species.

Effects of miR-190a-3p on Sevoflurane-induced postoperative cognitive dysfunction (POCD).

Postoperative cognitive dysfunction (POCD) is regularly observed in patients postsurgery due to the usage of anesthetics, including Sevoflurane. Research has confirmed the participation of oxidative stress (OS) and inflammation in the pathogenesis of POCD. Recently, the potential therapeutic function of miR-190a-3p against cognitive dysfunction has been reported. However, its role and mechanism in POCD are unclear. Our study will focus on the protective property and mechanism of miR-190a-3p on POCD to seek potential biomarkers and treatment targets for POCD. The animal model of POCD was constructed by the injection of Sevoflurane, followed by the administration of mimic negative control and miR-190a-3p. MiR-190a-3p was found to be downregulated in POCD rats. Declined time to explore the platform, swimming distance, and times that rats crossed the platform were observed in POCD rats, accompanied by increased secretion of proinflammatory cytokines, elevated malondialdehyde levels, repressed superoxide dismutase activity, and decreased levels of reduced glutathione, all of which were dramatically reversed by miR-190a-3p. Furthermore, the downregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and activation of toll-like receptor 4/nuclear factor-κB signaling were observed in POCD rats, which were greatly rescued by miR-190a-3p. Lastly, the Nrf2 luciferase activity and Nrf2 levels in HT22 cells were extremely improved by miR-190a-3p. Collectively, miR-190a-3p alleviated Sevoflurane-induced POCD in rats by repressing OS and inflammation.

An active glutamine/α-ketoglutarate/HIF-1α axis prevents pregnancy loss by triggering decidual IGF1+GDF15+NK cell differentiation.

Deficiency of decidual NK (dNK) cell number and function has been widely regarded as an important cause of spontaneous abortion. However, the metabolic mechanism underlying the crosstalk between dNK cells and embryonic trophoblasts during early pregnancy remains largely unknown. Here, we observed that enriched glutamine and activated glutaminolysis in dNK cells contribute to trophoblast invasion and embryo growth by insulin-like growth factor-1 (IGF-1) and growth differentiation factor-15 (GDF-15) secretion. Mechanistically, these processes are dependent on the downregulation of EGLN1-HIF-1α mediated by α-ketoglutarate (α-KG). Blocking glutaminolysis with the GLS inhibitor BPTES or the glutamate dehydrogenase inhibitor EGCG leads to early embryo implantation failure, spontaneous abortion and/or fetal growth restriction in pregnant mice with impaired trophoblast invasion. Additionally, α-KG supplementation significantly alleviated pregnancy loss mediated by defective glutaminolysis in vivo, suggesting that inactivated glutamine/α-ketoglutarate metabolism in dNK cells impaired trophoblast invasion and induced pregnancy loss.

Serum metabolic alterations in peritoneal dialysis patients with excessive daytime sleepiness.

Excessive daytime sleepiness (EDS) is associated with quality of life and all-cause mortality in the end-stage renal disease population. This study aims to identify biomarkers and reveal the underlying mechanisms of EDS in peritoneal dialysis (PD) patients. A total of 48 nondiabetic continuous ambulatory peritoneal dialysis patients were assigned to the EDS group and the non-EDS group according to the Epworth Sleepiness Scale (ESS). Ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) was used to identify the differential metabolites. Twenty-seven (male/female, 15/12; age, 60.1 ± 16.2 years) PD patients with ESS ≥ 10 were assigned to the EDS group, while twenty-one (male/female, 13/8; age, 57.9 ± 10.1 years) PD patients with ESS < 10 were defined as the non-EDS group. With UHPLC-Q-TOF/MS, 39 metabolites with significant differences between the two groups were found, 9 of which had good correlations with disease severity and were further classified into amino acid, lipid and organic acid metabolism. A total of 103 overlapping target proteins of the differential metabolites and EDS were found. Then, the EDS-metabolite-target network and the protein-protein interaction network were constructed. The metabolomics approach integrated with network pharmacology provides new insights into the early diagnosis and mechanisms of EDS in PD patients.

Effects and mechanisms of extremely cold environment on body response after trauma.

With the outbreak of the Ukrainian crisis, extremely cold environment warfare has once again become the focus of international attention. People exposed to extremely cold environments may suffer from cold damage, further aggravate trauma, trigger high disability and mortality rates, and even cause serious sequelae. To declare the effects and mechanisms of the extremely cold environment on the body after trauma, this paper reviews, firstly, physiological reaction of human body in an extremely cold environment. Then, the post-traumatic body response in an extremely cold environment was introduced, and finally, the sequelae of trauma in extremely cold environment was further summarized in the paper. The results indicated that extremely cold environment can cause a series of damage to the body, especially the body after trauma. The extremely cold factor is a double-edged sword, showing a favorable and unfavorable side in different aspects. Moreover, in addition to the trauma suffered by the body, the subsequent sequelae such as cognitive dysfunction, anxiety, depression and even post-traumatic stress disorder may also be induced. The paper summarizes the human body's physiological response in an extremely cold environment, and declares the effects and mechanisms of the extremely cold environment on the body after trauma, which may provide a theoretical basis for effectively improving the level of combat trauma treatment in extremely cold regions.

Identification of the Key Genes of Immune Infiltration in Dilated Cardiomyopathy.

Dilated cardiomyopathy (DCM) is a common cause of heart failure. In this study, we screened the immune infiltration-related genes associated with DCM to explore the potential molecular mechanisms and provide a basis for the early diagnosis and development of new immunotherapeutic targets. A dataset related to DCM was downloaded from the Gene Expression Omnibus (GEO) database. R software was applied to the genetic differential analysis of patients with DCM and healthy individuals, and the obtained differential expressed genes (DEGs) were screened for differentially expressed immune-related genes (DEIRGs) after comparison with the immune microsatellite database. Gene functional analysis established a protein interaction network (PPI). The immune infiltration in patients with DCM versus normal controls was assessed using the CIBERSORT algorithm, the hub genes were screened using the MOCDE app, and the hubs were validated in multiple datasets. A total of 246 DEGs were screened (adj. P < 0.05 and |logFC| > 0.3), and a total of 170 DEIRGs were compared. Gene Ontology analysis showed significant (adj. P < 0.05) Biological Process entries of 591, Cellular Component of 10, and Molecular Function of 39; Kyoto Encyclopedia of Genes and Genomes showed 20 significant entries, mainly focused on cytokines involved in immune-related response, etc. A protein interaction network comprising 28 hub DEGs was constructed in combination with the PPI network interactions. DEIRG was mainly distributed in the T-cell receptor pathway by immune infiltration detection analysis, and significant changes in central memory T-cells were found by analyzing T-cell-related subpathways, where INSR, HLA-B, IFITM1, and HBEGF were significantly differentially expressed. We selected 632 hospitalized patients for validation and found that INSR and HLA-B expression were associated with DCM development by Nomogram. The expression of HLA-B in peripheral blood T-cells was higher in DCM patients than in the normal group, as verified by qRT-PCR. However, the detailed mechanism needs to be further explored.

[Noise Exposure and Stress Hormone Levels:A Review].

Noise is one of the most common environmental hazards to which people are exposed,and the exposure to noise can cause not only hearing but also non-hearing damage.Although noise under safety limits may not affect the auditory system,it can cause changes in stress hormone levels,which is harmful to health.However,the current studies about the impact of noise on health mainly focus on the auditory system,and little is known about the relationship between noise and stress hormone levels.Therefore,this paper reviews the studies involving noise exposure and stress hormone levels,aiming to provide ideas for strengthening the prevention and control of noise hazards.

Identification of HMGCR as the anticancer target of physapubenolide against melanoma cells by in silico target prediction.

Physapubenolide (PB), a withanolide-type compound extracted from the traditional herb Physalis minima L., has been demonstrated to exert remarkable cytotoxicity against cancer cells; however, its molecular mechanisms are still unclear. In this study, we demonstrated that PB inhibited cell proliferation and migration in melanoma cells by inducing cell apoptosis. The anticancer activity of PB was further verified in a melanoma xenograft model. To explore the mechanism underlying the anticancer effects of PB, we carried out an in silico target prediction study, which combined three approaches (chemical similarity searching, quantitative structure-activity relationship (QSAR), and molecular docking) to identify the targets of PB, and found that PB likely targets 3-hydroxy-methylglutaryl CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate pathway, which promotes cancer cell proliferation, migration, and metastasis. We further demonstrated that PB interacted with HMGCR, decreased its protein expression and inhibited the HMGCR/YAP pathway in melanoma cells. In addition, we found that PB could restore vemurafenib sensitivity in vemurafenib-resistant A-375 cells, which was correlated with the downregulation of HMGCR. In conclusion, we demonstrate that PB elicits anticancer action and enhances sensitivity to vemurafenib by targeting HMGCR.

Combined analysis of human chorionic gonadotrophin concentrations at different time points after frozen-thawed blastocyst transfer can improve our ability to predict the pregnancy outcomes of single gestations.

In this study, we conducted a retrospective single-centre study of 1664 singleton pregnancies derived from frozen-thawed blastocyst transfer between January 2017 and December 2018. Analysis showed that there were 596 early pregnancy losses and 1068 ongoing pregnancies. We compared serum HCG (human chorionic gonadotophin) concentrations on days 12, 14, 19, and 21, between the pregnancy loss group and the ongoing pregnancy group. The cut-off level of HCG at each time point was calculated to predict pregnancy outcome. Joint analysis of two single HCG levels taken one week apart was carried out to improve predictive accuracy. The levels of HCG at four time points were significantly lower in the early pregnancy loss group than in the ongoing pregnancy group. According to the area under ROC (receiver operating characteristic curve) curves, all levels of HCG taken at four time points showed good ability to predict the outcome of pregnancy. The joint analysis of two single HCG levels taken one week apart further improved the accuracy of prediction.Impact statementWhat is already known on this subject? Multiple studies have shown that the maternal level of serum HCG is the best parameter for predicting the course of pregnancy.What do the results of this study add? The levels of HCG on days 12, 14, 19 and 21 were significantly lower in the early pregnancy loss group than in the group of ongoing pregnancies. According to the area under ROC curves, all levels of HCG taken at four time points showed a good ability to predict the outcome of pregnancy.What are the implications of these findings for clinical practice and/or further research? The joint analysis of two single HCG levels, taken one week apart, further improved the accuracy of prediction.

[Research on the Effects of NOX-Mediated Oxidative Stress and Hearing Loss].

Hearing loss is one of the most common chronic developmental diseases.The available studies have demonstrated that the occurrence and development of hearing loss is closely related to oxidative damage caused by oxidative stress.Nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase,NOX) contribute to the production of reactive oxygen and are classified into seven subtypes (NOX1,NOX2,NOX3,NOX4,NOX5,DUOX1,and DUOX2).To explore the relationship between oxidative stress and hearing loss,this paper reviews the latest research progress in the pathological mechanism of NOX-mediated oxidative stress and hearing loss.

Electrode-Electrolyte Interfacial Chemistry Modulation for Ultra-High Rate Sodium-Ion Batteries.

Sodium-ion batteries capable of operating at rate and temperature extremes are highly desirable, but elusive due to the dynamics and thermodynamics limitations. Herein, a strategy of electrode-electrolyte interfacial chemistry modulation is proposed. The commercial hard carbon demonstrates superior rate performance with 212 mAh g-1 at an ultra-high current density of 5 A g-1 in the electrolyte with weak ion solvation/desolvation, which is much higher than those in common electrolytes (nearly no capacity in carbonate-based electrolytes). Even at -20 °C, a high capacity of 175 mAh g-1 (74 % of its room-temperature capacity) can be maintained at 2 A g-1 . Such an electrode retains 90 % of its initial capacity after 1000 cycles. As proven, weak ion solvation/desolvation of tetrahydrofuran greatly facilitates fast-ion diffusion at the SEI/electrolyte interface and homogeneous SEI with well-distributed NaF and organic components ensures fast Na+ diffusion through the SEI layer and a stable interface.

A Photoelectrochemical Nanoreactor for Single-Cell Sampling and Near Zero-Background Faradaic Detection of Intracellular microRNA.

Rational utilization of the rich light-bio-matter interplay taking place in single-cell analysis represents a new technological direction in the field. The light-fueled operation is expected to achieve advanced photoelectrochemical (PEC) single-cell analysis with unknown possibilities. Here, a PEC nanoreactor capable of single-cell sampling and near zero-background Faradaic detection of intracellular microRNA (miR) is devised by the construction of a small reaction chamber accommodating the target-triggered hybridization chain reaction for binding the metallointercalator of [Ru(bpy)2 (dppz)]2+ as the signal reporter. Light stimulation of the dsDNA/metallointercalator adduct will induce the generation of photocurrents, underpinning a zero-biased and near zero-background PEC method toward Faradaic detection of non-electrogenic miR at the single-cell level. Using this nanotool, lower miR concentration in the near-nucleus region than that in the main cytosol was revealed.

Rational Utilization of Photoelectrochemistry of Photosystem II for Self-Powered Photocathodic Detection of MicroRNA in Cells.

The photoanode, photosystem II (PSII)/hierarchical inverse opal (IO) TiO2, is coupled to the complementary photocathode, PbS quantum dots (QDs)/DNA probes, which is then integrated into a two-compartment photoelectrochemical (PEC) cell to achieve a self-powered system to enable photocathodic detection of microRNA-10b from HeLa cells. In such a system, all of the PSII catalytic products, i.e., electrons, protons, and O2, were rationally utilized and could overcome the general issue of varied O2 levels in photocathodic detection. The correlation between the target-triggered formation of the DNA complexes and the catalytic reduction of the dissolved O2 makes possible the steady microRNA-10b detection with good sensitivity and selectivity. This work has unveiled the ability of PSII to construct self-powered detecting devices and shed light on its application in new arenas.

Target-Triggered Assembly in a Nanopipette for Electrochemical Single-Cell Analysis.

Engineered nanopipette tools have recently emerged as a powerful approach for electrochemical nanosensing, which has major implications in both fundamental biological research and biomedical applications. Herein, we describe a generic method of target-triggered assembly of aptamers in a nanopipette for nanosensing, which is exemplified by sensitive and rapid electrochemical single-cell analysis of adenosine triphosphate (ATP), a ubiquitous energy source in life and important signaling molecules in many physiological processes. Specifically, a layer of thiolated aptamers is immobilized onto a Au-coated interior wall of a nanopipette tip. With backfilled pairing aptamers, the engineered nanopipette is then used for probing intracellular ATP via the ATP-dependent linkage of the split aptamers. Due to the higher surface charge density from the aptamer assembly, the nanosensor would exhibit an enhanced rectification signal. Besides, this ATP-responsive nanopipette tool possesses excellent selectivity and stability as well as high recyclability. This work provides a practical single-cell nanosensor capable of intracellular ATP analysis. More generally, integrated with other split recognition elements, the proposed mechanism could serve as a viable basis for addressing many other important biological species.

A Practical Electrochemical Nanotool for Facile Quantification of Amino Acids in Single Cell.

Though significant advances are made in the arena of single-cell electroanalysis, quantification of intracellular amino acids of human cells remains unsolved. Exemplified by l-histidine (l-His), this issue is addressed by a practical electrochemical nanotool synergizing the highly accessible nanopipette with commercially available synthetic DNAzyme. The fabricated nanotools are screened before operation of a single-use manner, and the l-His-provoked cleavage of the DNA molecules can be sensibly transduced by the ionic current rectification response, the intrinsic property of nanopipette governed by its interior surface charges. Regional distribution of cytosolic l-His level in human cells is electrochemically quantified for the first time, and time-dependent drug treatment effects are further revealed. This work unveils the possibility of electrochemistry for quantification of cytosolic amino acids of a spatial- and time-based manner and ultimately enables a better understanding of amino acid-involved events in living cells.

Dissolution and processing of silk fibroin for materials science.

In recent decades, silk fibroin (SF) from silkworm Bombyx mori has been extensively researched and applied in several fields, including: cosmetics, biomedicine and biomaterials. The dissolution and regeneration of SF fibers is the key and prerequisite step for the application of silk protein-based materials. Various solvents and dissolving systems have been reported to dissolve SF fibers. However, the dissolution process directly affects the characteristics of SF and particularly impacts the mechanical properties of the resulting silk biomaterials in subsequent processing. The purpose of this review is to summarize the common solvents, the dissolution methods for silk protein, the properties of the resulting SF protein. The suitable use of SF dissolved in the corresponding solvent was also briefly introduced. Recent applications of SF in various biomaterials are also discussed.