Electrochemical detection of the neurotransmitter glutamate and the effect of the psychotropic drug riluzole on its oxidation response.

Glutamate is the main excitatory neurotransmitter in the brain and plays a leading role in degenerative diseases, such as motor neuron diseases. Riluzole is a glutamate regulator and a therapeutic drug for motor neuron diseases. In this work, the interaction between glutamate and riluzole was studied using cyclic voltammetry and square-wave voltammetry at a glassy carbon electrode (GCE). It was shown that glutamate underwent a two-electron transfer reaction on the GCE surface, and the electrochemical detection limits of glutamate and riluzole were 483 µmol/L and 11.47 µmol/L, respectively. The results confirm that riluzole can promote the redox reaction of glutamate. This work highlights the significance of electrochemical technology in the sensing detection of the interaction between glutamate and related psychotropic drugs.

The Role of KDM2A and H3K36me2 Demethylation in Modulating MAPK Signaling During Neurodevelopment.

Intellectual disability (ID) is a condition characterized by cognitive impairment and difficulties in adaptive functioning. In our research, we identified two de novo mutations (c.955C>T and c.732C>A) at the KDM2A locus in individuals with varying degrees of ID. In addition, by using the Gene4Denovo database, we discovered five additional cases of de novo mutations in KDM2A. The mutations we identified significantly decreased the expression of the KDM2A protein. To investigate the role of KDM2A in neural development, we used both 2D neural stem cell models and 3D cerebral organoids. Our findings demonstrated that the reduced expression of KDM2A impairs the proliferation of neural progenitor cells (NPCs), increases apoptosis, induces premature neuronal differentiation, and affects synapse maturation. Through ChIP-Seq analysis, we found that KDM2A exhibited binding to the transcription start site regions of genes involved in neurogenesis. In addition, the knockdown of KDM2A hindered H3K36me2 binding to the downstream regulatory elements of genes. By integrating ChIP-Seq and RNA-Seq data, we made a significant discovery of the core genes' remarkable enrichment in the MAPK signaling pathway. Importantly, this enrichment was specifically linked to the p38 MAPK pathway. Furthermore, disease enrichment analysis linked the differentially-expressed genes identified from RNA-Seq of NPCs and cerebral organoids to neurodevelopmental disorders such as ID, autism spectrum disorder, and schizophrenia. Overall, our findings suggest that KDM2A plays a crucial role in regulating the H3K36me2 modification of downstream genes, thereby modulating the MAPK signaling pathway and potentially impacting early brain development.

Effects of olanzapine and lithium carbonate antipsychotic agents on dopamine oxidation.

Olanzapine (OLZ) and lithium carbonate (Li2CO3) are the main drugs for treating mental disorders related to dopamine (DA). A highly conductive carbon paper sensing electrode is used to investigate the effects of OLZ and Li2CO3 on DA oxidation due to its amplification of oxidation peak currents. Different chemical properties of drugs have different effects on DA oxidation. The presence of OLZ fouling on the electrode surface due to the irreversible adsorption weakens the sensing activity and thus reduces the DA oxidation peak current. However, the fixed DA oxidation peak potential at 0.22 V indicates no interaction between them. The hydrolysis effect of Li2CO3 increases the solution pH from 7.47 to 9.73, which promotes the deprotonation of DA, leading to a 156 mV negative shift of the DA oxidation peak potential. Additionally, a 94% decrease of the DA peak current may be related to the generation of polydopamine in alkaline media.

Recent strategies for electrochemical sensing detection of miRNAs in lung cancer.

MicroRNAs (miRNAs) associated with lung cancer are diversifying. MiR-21, Let-7, and miR-141 are common diagnostic targets. Some new lung cancer miRNAs, such as miR-25, miR-145, and miR-126, have received increasing attention. Although various techniques are available for the analysis of lung cancer miRNAs, electrochemistry has been recognized for its high sensitivity, low cost, and rapid response. However, how to realize the signal amplification is one of the most important contents in the design of electrochemical biosensors. Herein, we mainly introduce the amplification strategy based on enzyme-free amplification and signal conversion, including non-linear HCR, catalytic hairpin assembly (CHA), electrochemiluminescence (ECL), and Faraday cage. Furthermore, new progress has emerged in the fields of nanomaterials, low oxidation potential, and simultaneous detection of multiple targets. Finally, we summarize some new challenges that electrochemical techniques may encounter in the future, such as improving single-base discrimination ability, shortening electrochemical detection time, and providing real body fluid samples assay.

Ho2O3-TiO2 Nanobelts Electrode for Highly Selective and Sensitive Detection of Cancer miRNAs.

The design and engineering of effective electrode materials is critical in the development of electrochemical sensors. In the present study, Ho2O3-TiO2 nanobelts were synthesized by an alkaline hydrothermal process. The structure and morphology were investigated by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) measurements. The Ho2O3-TiO2 nanobelts showed a distinctly enhanced (004) reflection peak and rough surfaces and were used for the electrochemical selective sensing of various cancer miRNAs, such as prostate cancer miR-141, osteosarcoma miR-21, and pancreatic cancer miR-1290. Voltammetric measurements showed an oxidation peak at +0.4, +0.2, and +1.53 V for the three different cancer biomarkers, respectively, with the detection limit as low as 4.26 aM. The results suggest that the Ho2O3-TiO2 nanobelts can be used as active materials to detect early cancers, for in vitro screening of anticancer drugs, and molecular biology research.

Protein detection based on rolling circle amplification sensors.

Rolling circle amplification (RCA) is an isothermal process under the action of DNA polymerases. Large-scale DNA templates have been generated using RCA for target detection. Some signal amplification strategies including optical sensors and electrochemical sensors based on RCA have been applied to achieve sensitive detection. Sensors based on RCA have attracted increasing interest. Advances in RCA-based sensors for protein detection are reviewed in this paper. The advantages and detection mechanisms of sensors based on RCA are revealed and discussed. Finally, possible challenges and future perspectives are also outlined.

Electrochemical sensing of pancreatic cancer miR-1290 based on yeast-templated mesoporous TiO2 modified electrodes.

Electrochemical sensing is an effective, low-cost technology for cancer detection. In this study, mesoporous TiO2 was prepared via biomimetic synthesis based on yeast cell templates, and used to prepare a modified electrode for the sensitive detection of pancreatic cancer miR-1290. The structure and the morphology of the TiO2 were characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherm (NADI), Atomic force microscopy (AFM), and electron probe microanalysis (EPMA). As a sensing active material, the yeast-templated mesoporous TiO2 could detect pancreatic cancer miRNAs with single-nucleotide discrimination. The sample prepared by calcination at 400 °C showed the best electrochemical sensing activity. Moreover, compared with the blank electrode, the yeast mesoporous TiO2 sensing electrode could oxidize the pancreatic cancer microRNAs at a lower potential, which minimized the interference from oxygen evolution reaction at high potentials.

Mini-Disk Capillary Array Coupling with LAMP for Visual Detection of Multiple Nucleic Acids using Genetically Modified Organism Analysis as an Example.

Convenient, portable, and low-cost multiplex nucleic acid testing (NAT) systems are the trends in the fields of food safety, environmental microorganisms, molecular diagnosis, etc. In this study, we developed a novel system for visual monitoring of multiple nucleic acids combining a mini-disk capillary array (diameter = 17 mm, embedded with 6-10 capillaries), visual loop-mediated isothermal amplification (LAMP), and quick DNA extraction called mDC-LAMP. The performance and applicability of mDC-LAMP in testing multiple nucleic acids were evaluated and verified employing genetically modified contents analysis as an example. All of the results confirmed that mDC-LAMP has the advantages of high specificity without any cross contamination, high sensitivity with a limit of detection of 25 copies/reaction, high throughput with flexible channel sensors, easy fabrication, and low costs. We believe that mDC-LAMP is a competitive choice for on-spot monitoring of multiple nucleic acids in terms of the easy fabrication/operation, low costs, and suitable performance presented in the nucleic acids test.

Analysis of differential expression profile of miRNA in peripheral blood of patients with lung cancer.

PURPOSE: To identify potential molecular targets for lung cancer intervention and diagnosis, we analyzed the differential miRNA expression of peripheral blood between lung cancer patients and healthy controls. METHODS: Three pairs of cases' and controls' peripheral blood samples were evaluated for miRNA expression by microarray. 12 miRNAs were selected for RT-PCR validation and target genes prediction. In addition, 4 miRNAs were selected for future validation by RT-PCR in a large sample of 145 cases and 55 frequency-matched healthy controls. RESULTS: A total of 338 differentially expressed miRNAs were screened and identified by microarray. According to the fold changes, the top ten upregulated miRNAs were hsa-miR-124-3p, hsa-miR-379-5p, hsa-miR-3655, hsa-miR-450b-5p, hsa-miR-29a-5p, hsa-miR-200a-3p, hsa-miR-542-3p, hsa-miR-138-5p, hsa-miR-219a-2-3p, and hsa-miR-4701-3p, and the top ten downregulated miRNAs were hsa-miR-34c-5p, hsa-miR-135a-5p, hsa-miR-132-3p, hsa-miR-3178, hsa-miR-4449, hsa-miR-4999-3p, hsa-miR-1246, hsa-miR-4424, hsa-miR-1252-5p, and hsa-miR-24-2-5p. RT-PCR verification of the 12 miRNAs revealed that 5 of 8 upregulated miRNAs, 2 of 4 downregulated miRNAs showed a significant difference between the cases and controls (P < .05). A large number of target genes and their functional set showed overlapping among the 453 predicted target genes of the 12 miRNAs (P < .01). RT-PCR in the large sample confirmed the significant differential expression level of hsa-miR-29a-5p, hsa-miR-135a-5p, hsa-miR-542-3p, and hsa-miR-4491 between cases and controls (P < .05), and three of these microRNA, except hsa-miR-29a-5p, were significant after Bonferroni correction for adjustment of multiple comparisons. CONCLUSION: There was a significant difference in miRNAs expression in the peripheral blood between lung cancer patients and healthy controls, and 4 miRNAs were validated by a large-size sample.

Shikonin, vitamin K3 and vitamin K5 inhibit multiple glycolytic enzymes in MCF-7 cells.

Glycolysis is the most important source of energy for the production of anabolic building blocks in cancer cells. Therefore, glycolytic enzymes are regarded as potential targets for cancer treatment. Previously, naphthaquinones, including shikonin, vitamin K3 and vitamin K5, have been proven to decrease the rate of glycolysis in cancer cells, which is partly due to suppressed pyruvate kinase activity. In the present study, enzymatic assays were performed using MCF-7 cell lysate in order to screen the profile of glycolytic enzymes in cancer cells inhibited by shikonin, vitamin K3 and vitamin K5, in addition to pyruvate kinase. Results revealed that hexokinase, phosphofructokinase-1, fructose bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase and pyruvate kinase produced in the process of glycolysis were inhibited by shikonin, vitamin K3 and vitamin K5. The results indicated that shikonin, vitamin K3 and vitamin K5 are chemical inhibitors of glycolytic enzymes in cancer cells and have potential uses in translational medical applications.

Au/TiO2 nanobelt heterostructures for the detection of cancer cells and anticancer drug activity by potential sensing.

Cancer is a cell dysfunction disease. The detection of cancer cells is extremely important for early diagnosis and clinical treatments. At present, the pretreatment for the detection of cancer cells is costly, complicated and time-consuming. As different species of the analytes may give rise to specific voltammetric signals at distinctly different potentials, simple potential sensing has the specificity to detect different cellular species. By taking advantage of the different electrochemical characteristics of normal cells, cancer cells and biointeractions between anticancer drugs and cancer cells, we develop a specific, sensitive, direct, cost-effective and rapid method for the detection of cancer cells by electrochemical potential sensing based on Au/TiO2 nanobelt heterostructure electrodes that will be of significance in early cancer diagnosis, in vitro screening of anticancer drugs  and molecular biology research.

Fabricating high performance lithium-ion batteries using bionanotechnology.

Designing, fabricating, and integrating nanomaterials are key to transferring nanoscale science into applicable nanotechnology. Many nanomaterials including amorphous and crystal structures are synthesized via biomineralization in biological systems. Amongst various techniques, bionanotechnology is an effective strategy to manufacture a variety of sophisticated inorganic nanomaterials with precise control over their chemical composition, crystal structure, and shape by means of genetic engineering and natural bioassemblies. This provides opportunities to use renewable natural resources to develop high performance lithium-ion batteries (LIBs). For LIBs, reducing the sizes and dimensions of electrode materials can boost Li(+) ion and electron transfer in nanostructured electrodes. Recently, bionanotechnology has attracted great interest as a novel tool and approach, and a number of renewable biotemplate-based nanomaterials have been fabricated and used in LIBs. In this article, recent advances and mechanism studies in using bionanotechnology for high performance LIBs studies are thoroughly reviewed, covering two technical routes: (1) Designing and synthesizing composite cathodes, e.g. LiFePO4/C, Li3V2(PO4)3/C and LiMn2O4/C; and (2) designing and synthesizing composite anodes, e.g. NiO/C, Co3O4/C, MnO/C, α-Fe2O3 and nano-Si. This review will hopefully stimulate more extensive and insightful studies on using bionanotechnology for developing high-performance LIBs.

Enhancement of electrochemical differentiation ability of nucleobases in phosphate buffer solution at pH 7.4.

The electrochemical behavior of nucleobases has been studied in 0.1 M phosphate buffer solution at pH 7.4, using a bare graphite electrode. Guanine and adenine produced well-defined oxidation peaks at about +0.63 and +0.91 V at 100 mV/s, respectively. Nucleobases exhibit an irreversible and hybrid-controlled electrochemical process, including adsorption and diffusion. The nucleobase oxidation peaks shift due to the selective interactions of nucleobases with each other. The oxidation peaks for three different pyrimidine bases, uracil, cytosine, and thymine, can be clearly identified at +1.26, +1.41, and +1.32 V, respectively. These differences in the electrochemical behavior among nucleobases can be attributed to their different chemical structures.

A strategy for sequencing based on rolling-circle amplification on a microarray.

The sequencing of DNA fragments has become an important facet of the study of genomes. Parallel genomic DNA fragments displayed on a microarray play a key role in producing a template in next generation DNA sequencing. Here, we developed a technique to display parallel genomic DNA fragments based on the reaction with Bst DNA polymerase on a microarray. One of the hyperbranched rolling circle amplification (HRCA) primers was modified with acrylamide. HRCA products could be localized near the respective templates in polyacrylamide gel. DNA colonies produced by HRCA were displayed massively and in parallel on a microarray. Then the probe labeled with Cy 5 was hybridized to DNA colonies and extension reactions with Cy 5-labeled deoxyribonucleoside triphosphates (dNTPs) were carried out. The results show the signals of hybridization and extension reactions could be obtained. This provided a strategy for high-throughput sequencing.

Nano-p-n junction heterostructure TiO2 nanobelts for the electrochemical detection of anticancer drug and biointeractions with cancer cells.

Nano-p-n junction heterostructures based on TiO2 nanobelts with enhanced (001) facets were produced by assembling p-type semiconductor NiO nanoparticles on n-type surface-coarsened TiO2 nanobelt surfaces. The heterostructures were then used as the sensing electrode for the electrochemical detection of anticancer drugs O6-benzylguanine (O6BG) and lung cancer cells. O6BG exhibited an irreversible diffusion-controlled electrochemical process with an oxidation peak clearly identified at +0.78 V. For lung cancer cells one oxidation peak was found at +1.1 V and two reduction peaks at +0.30, and +0.90 V. These voltammetric features disappeared when O6BG was added to the lung cancer cells, which was ascribed to the structural changes of the cell membranes caused by the anticancer drug. These results suggested that nano-p-n junction heterostructures based on TiO2 nanobelts might serve as promising candidates for biosensing applications of anticancer drugs and tumor cells that will be of significance in diagnostic medicine, cancer diagnosis and molecular biology research.

Electrocatalytic oxidation of nucleobases by TiO2 nanobelts.

Two kinds of TiO(2) nanobelts were prepared from commercial P-25 powders via an alkaline hydrothermal method with and without an acid etching process. The uncauterized nanobelts (TNs) exhibited a smooth surface, and mixed phases of anatase and TiO(2) (B), whereas the cauterized ones (CTNs) displayed a rough surface and a pure anatase structure. TNs and CTNs were then deposited onto a glassy carbon electrode (GCE) surface with a conductive adhesive (CA), and the resulting chemically modified electrodes exhibited electrocatalytic activities in the oxidation of nucleobases in a 0.1 M phosphate buffer solution (PBS) at pH 7.4. For guanine and adenine, well-defined oxidation peaks were observed in voltammetric measurements at about +0.62 and +0.89 V, respectively, at a potential sweep rate of 100 mV s(-1), whereas for cytosine, uracil and thymine, the voltammetric features were not obvious. The average surface coverages (Γ) of guanine and adenine on the CTNs/CA/GCE electrode were estimated to be 4.75 × 10(-10) and 7.44 × 10(-10) mol cm(-2), respectively, which were about twice those at the TNs/CA/GCE electrode. The enhanced activity of the CTN-based electrode towards purine nucleobase oxidation was ascribed to the large specific surface area and anatase structures with enhanced (001) facets of the CTN that facilitated adsorption of the analytes onto the electrode surface and charge transport through the electrode surface layer.

In vitro biomimetic construction of hydroxyapatite-porcine acellular dermal matrix composite scaffold for MC3T3-E1 preosteoblast culture.

The application of porous hydroxyapatite-collagen (HAp-Collagen) as a bone tissue engineering scaffold is hindered by two main problems: its high cost and low initial strength. As a native 3-dimenssional collagen framework, purified porcine acellular dermal matrix (PADM) has been successfully used as a skin tissue engineering scaffold. Here we report its application as a matrix for the preparation of HAp to produce a bone tissue scaffold through a biomimetic chemical process. The HAp-PADM scaffold has two-level pore structure, with large channels (∼100 µm in diameter) inherited from the purified PADM microstructure and small pores (<100 nm in diameter) formed by self-assembled HAp on the channel surfaces. The obtained HAp-PADM scaffold (S15D) has a compressive elastic modulus as high as 600 kPa. The presence of HAp in sample S15D reduces the degradation rate of PADM in collagenase solution at 37°C. After 7 day culture of MC3T3-E1 pre-osteroblasts, MTT data show no statistically significant difference on pure PADM framework and HAp-PADM scaffold (p > 0.05). Because of its high strength and nontoxicity, its simple preparation method, and designable and tailorable properties, the HAp-PADM scaffold is expected to have great potential applications in medical treatment of bone defects.

High-performance TiO(2) from Baker's yeast.

Based on the biomineralization assembly concept, a biomimetic approach has been developed to synthesize high-performance mesoporous TiO(2). The key step of this approach is to apply Baker's yeast cells as biotemplates for deriving the hierarchically ordered mesoporous anatase structure. The mechanism of formation of the yeast-TiO(2) is revealed by characterizing its morphology, microstructure, and chemical composition. The yeast-TiO(2) exhibits outstanding photocatalytic performance. Under visible-light irradiation, the removal efficiency of chemical oxygen demand (COD) and color of the paper industry wastewater has reached 80.3% and nearly 100%, respectively. The approach may open new vistas for fabricating advanced mesoporous materials under ambient condition.

Enhancement of ethanol vapor sensing of TiO2 nanobelts by surface engineering.

TiO(2) nanobelts were prepared by a hydrothermal process, and the structures were manipulated by surface engineering, including surface coarsening by an acid-corrosion procedure and formation of Ag-TiO(2) heterostuctures on TiO(2) nanobelts surface by photoreduction. Their performance in the detection of ethanol vapor was then examined and compared by electrical conductivity measurements at varied temperatures. Of the sensors based on the four nanobelt samples (TiO(2) nanobelts, Ag-TiO(2) nanobelts, surface-coarsened TiO(2) nanobelts, and surface-coarsened Ag-TiO(2) nanobelts), they all displayed improved sensitivity, selectivity, and short response times for ethanol vapor detection, in comparison with sensors based on other oxide nanostructures. Importantly, the formation of Ag-TiO(2) heterostuctures on TiO(2) nanobelts surface and surface coarsening of TiO(2) nanobelts were found to lead to apparent further enhancement of the sensors sensitivity, as well as a decrease of the optimal working temperature. That is, within the present experimental context, the vapor sensor based on surface-coarsened Ag-TiO(2) composite nanobelts exhibited the best performance. The sensing mechanism was interpreted on the basis of the surface depletion model, and the improvement by oxide surface engineering was accounted for by the chemical sensitization mechanism. This work provided a practical approach to the enhancement of gas sensing performance by one-dimensional oxide nanomaterials.

Ag2O/TiO2 nanobelts heterostructure with enhanced ultraviolet and visible photocatalytic activity.

Ag(2)O/TiO(2) heterostructure with high photocatalytic activity both in ultraviolet and visible-light region was synthesized via a simple and practical coprecipitation method by using surface-modified TiO(2) nanobelts as substrate materials. The as-prepared heterostructure composite included Ag(2)O nanoparticles assembled uniformly on the rough surface of TiO(2) nanobelts. Comparing with pure TiO(2) nanobelts and Ag(2)O nanoparticles, the composite photocatalyst with a wide weight ratio between TiO(2) and Ag(2)O exhibited enhanced photocatalytic activity under ultraviolet and visible light irradiation in the decomposition of methyl orange (MO) aqueous solution. On the basis of the characterization by X-ray diffraction, photoluminescence and UV-vis diffuse reflectance spectroscopies, two mechanisms were proposed to account for the photocatalytic activity of Ag(2)O/TiO(2) nanobelts' heterostructure.