Triblock probe-polyA-probe electrochemical interfacial engineering for the sensitive analysis of RNAi plants.

RNA interference (RNAi) is currently under fast development, which brings improved crop quality and new activity against pests in agriculture, by producing RNAs to specifically inhibit gene expression. This technology, in turn, creates a pressing need for sensitive and specific analytical methods of exogenous RNA molecules in genetically modified (GM) crops for safety assessment and regulation of RNAi plants and their products. In this work, we developed a novel RNA electrochemical biosensor for the analysis of GM maize samples based on a polyA-DNA capturing probe containing three DNA segments: the central polyA segment combined onto a gold electrode surface with adjustable configuration and density, and two flanking DNA probes simultaneously captured the RNA targets through hybridization. Both the assembling and hybridization capability of our probe were demonstrated, and we systematically optimized the analytical conditions. Finally, the ultrasensitive detection of 10 fM RNA was realized without any amplification processes, and the specificity was verified by analyzing non-target maize samples. Our electrochemical biosensor provided a reliable and convenient measurement strategy for RNAi safety and quality assessment, and more importantly, our PAP (probe-polyA-probe) capturing probe exhibited an innovative design for the detection of large RNA molecules with complex secondary structures.

A polyA DNA probe-based ultra-sensitive and structure-distinguishable electrochemical biosensor for the analysis of RNAi transgenic maize.

Since the application of RNA interference (RNAi) is rapidly developing in GMO technology, accurate and sensitive detection of functional RNA molecules was urgently needed, for the safety and functional assessment of RNAi crops. In this work, we developed an electrochemical biosensor for transgene-derived long RNA based on a poly-adenine (polyA) DNA capture probe. The polyA self-assembling monolayer (SAM) provided enhanced interface stability and optimized surface density for the subsequent hybridization of the long RNA molecule. A multiple reporter probe system (MRP) containing 12 reporter probes (RPs) and 2 spacers was applied to open the complex molecular secondary structure and hybridize with the long RNA, with the critical assistance of dimethyl sulfoxide (DMSO). By using 3 addressable RPs, structural recognition was performed among long stem-loop RNA, long dsRNA (no loop), and siRNA. Excellent selectivity was achieved when the extracted total RNA samples were directly analyzed. When reverse transcription recombinase polymerase amplification (RT-RPA) technology was combined, the sensitivity was improved to 10 aM. To the best of our knowledge, this is the first electrochemical biosensor with the excellent capability of quantification and structural analysis of the long RNA of the RNAi GMO. Our work shows great potential in a wide range of RNAi GMO samples.

Ultrasensitive Electrochemical DNA Biosensor Based on a Label-Free Assembling Strategy Using a Triblock polyA DNA Probe.

Multiblock DNA probe attracted a large amount of scientific attention, for the development of multitarget biosensor and improved specificity/sensitivity. However, the development of multiblock DNA probes highly relied on the chemical synthesis of organic linkers or nanomaterials, which limited their practicability and biological compatibility. In this work, we developed a label-free assembling strategy using a triblock DNA capture probe, which connects two DNA probes with its intrinsic polyA fragment (probe-PolyA-probe, PAP). The middle polyA segment has a high affinity to the gold electrode surface, leading to excellent reproducibility, stability, and regeneration of our biosensor. Two flanking capture probes were tandemly co-assembled on the electrode surface with consistent spatial relationship and exactly the same amount. When combined with the target DNA, the hybridization stability was improved, because of the strong base stacking effect of two capture probes. The sensitivity of our biosensor was proved to be 10 fM, with a wide analysis range between 10 fM to 1 nM. Our PAP-based biosensor showed excellent specificity when facing mismatched DNA sequences. Even single nucleotide polymorphisms can be distinguished by each probe. The excellent practicability of our biosensor was demonstrated by analyzing genomic DNA both with and without PCR amplification.

Prediction of Pulmonary Arterial Hypertension in Chronic Obstructive Lung Disease from Three-Dimensional Vectorcardiographic Parameters.

AIM: The objective of our study was to assess diagnostic value of three-dimensional (3D) vectorcardiographic (VCG) parameters in detecting pulmonary arterial hypertension (PAH) in chronic obstructive lung disease (COLD) with and without right ventricular hypertrophy (RVH). METHODS: The study group of 62 patients with COPD was stratified on the basis of color Doppler echocardiographic findings into three subgroups: non-PAH (n = 23), PAH without RVH (n = 22), and PAH with RVH (n = 17). Pairwise differences between the subgroups were evaluated by one-way analysis of variance, and Pearson correlation analysis was used to evaluate the significance of the correlations between pulmonary arterial systolic pressure (PASP) and various VCG parameters. RESULTS: The azimuth of the QRS vector decreased from -24° in the non-PAH group to -62° in PAH without RVH and to -140° in PAH with RVH (P < 0.01 for pairwise differences between all three groups). Similar significant decrease was observed for the azimuth of the ventricular gradient (VG) vector. Spatial QRS/T angle increased from 69° in the non-PAH group to 115° in PAH without RVH (P < 0.01). In the PAH group with RVH, QRS/T angle was 94° (P < 0.05 for difference from the non-PAH group). There was a significant correlation between PASP and QRS/T angle (r = 0.89, P < 0.05) and between PASP and the azimuth of the VG vector (r = 0.86, P < 0.05). PASP increase from linear regression model was 0.8 mmHg for a QRS/T angle increase by 10° and 1.3 mmHg for each 10° increase in the azimuth of the VG vector. CONCLUSION: 3DVCG parameters are potentially useful for predicting PASP in COLD patients, and possibly also for differentiation between COLD patients with PAH and RVH from those without RVH.

THE EFFECTS OF DRAINAGE TUBE ON PAIN AND FUNCTIONAL RECOVERY AFTER UNICOMPARTMENTAL KNEE ARTHROPLASTY.

Objective: The objective of this study was to evaluate the impact of drainage tube placement on postoperative pain, recovery, and opioid consumption within a 72-hour period following unicompartmental knee arthroplasty (UKA). Methods: Patients with medial knee osteoarthritis who underwent UKA from January 2019 to August 2020 were enrolled in the study and divided into two groups based on whether they received a drain postoperatively. Results: The drainage group had significantly lower VAS scores on day 1, day 2, and day 3, in addition to significantly smaller changes in the circumference of the knee joint within 3 days postoperatively (P <0.05). The ROM in the drainage group significantly increased at 3 days and 1 month post-surgery, with a statistically significant difference in morphine consumption between the two groups at 3 days (P<0.05). The incidence of postoperative nausea and vomiting (5 cases) and wound bleeding (1 case) was lower in the drainage group compared to the non-drainage group (P<0.05). Conclusions: The placement of a drainage tube in UKA may reduce the swelling of knee joint and pain, which not only reduces the use of Opioid but also facilitates early functional activities of the knee joint. Level of Evidence III; Retrospective Comparative Study.

Objetivo: O objetivo deste estudo foi avaliar o impacto da implantação do tubo de drenagem na dor pós-operatória, na recuperação e no consumo de opioides em um período de 72 horas após a artroplastia unicompartimental do joelho (UKA). Métodos: Pacientes com osteoartrite medial do joelho submetidos à UKA de janeiro de 2019 a agosto de 2020 foram incluídos no estudo e divididos em dois grupos com base no fato de terem ou não recebido um dreno no pós-operatório. Resultados: O grupo de drenagem apresentou escores EVA significativamente menores no dia 1, no dia 2 e no dia 3, além de alterações significativamente menores na circunferência da articulação do joelho em 3 dias de pós-operatório (P <0,05). A ADM no grupo de drenagem aumentou significativamente em 3 dias e 1 mês após a cirurgia, com uma diferença estatisticamente significativa no consumo de morfina entre os dois grupos em 3 dias (P<0,05). A incidência de náuseas e vômitos no pós-operatório(5 casos) e sangramento da ferida (1 caso) foi menor no grupo de drenagem em comparação com o grupo sem drenagem (P<0,05). Conclusão: A utilização de tubo de drenagem na UKA pode reduzir o edema articular do joelho e a dor, reduzindo o uso de opioides e facilitando as atividades funcionais iniciais da articulação do joelho. Nível de Evidência III; Estudo Comparativo Retrospectivo.

A highly sensitive and selective competition assay for the detection of cysteine using mercury-specific DNA, Hg and Sybr Green I.

We here report a rapid, sensitive, selective and label-free fluorescence detection method for cysteine (Cys). The conformation of mercury-specific DNA (MSD) changes from a random coil form to a hairpin structure in the presence of Hg2+ due to the formation of a thymine-Hg2+ -thymine (T-Hg2+ -T) complex. Cys can selectively coordinate with Hg2+ and extract it from the thymine-Hg2+ -thymine complex. The hairpin structure dehybridizes and the fluorescence intensity of Sybr Green I (SG) decreases upon addition of Cys because SG efficiently discriminates mercury-specific DNA and mercury-specific DNA/Hg2+ complex. The detection can be finished within 5 min with high sensitivity and selectivity. In addition, we can obtain variable dynamic ranges for Cys by changing the concentration of MSD/Hg2+.

The effects of drainage tube on pain and functional recovery after unicompartmental knee arthroplasty / Efeitos do tubo de drenagem na dor e recuperação funcional após artroplastia unicompartimental do joelho

ABSTRACT Objective: The objective of this study was to evaluate the impact of drainage tube placement on postoperative pain, recovery, and opioid consumption within a 72-hour period following unicompartmental knee arthroplasty (UKA). Methods: Patients with medial knee osteoarthritis who underwent UKA from January 2019 to August 2020 were enrolled in the study and divided into two groups based on whether they received a drain postoperatively. Results: The drainage group had significantly lower VAS scores on day 1, day 2, and day 3, in addition to significantly smaller changes in the circumference of the knee joint within 3 days postoperatively (P <0.05). The ROM in the drainage group significantly increased at 3 days and 1 month post-surgery, with a statistically significant difference in morphine consumption between the two groups at 3 days (P<0.05). The incidence of postoperative nausea and vomiting (5 cases) and wound bleeding (1 case) was lower in the drainage group compared to the non-drainage group (P<0.05). Conclusions: The placement of a drainage tube in UKA may reduce the swelling of knee joint and pain, which not only reduces the use of Opioid but also facilitates early functional activities of the knee joint. Level of Evidence III; Retrospective Comparative Study.

RESUMO Objetivo: O objetivo deste estudo foi avaliar o impacto da implantação do tubo de drenagem na dor pós-operatória, na recuperação e no consumo de opioides em um período de 72 horas após a artroplastia unicompartimental do joelho (UKA). Métodos: Pacientes com osteoartrite medial do joelho submetidos à UKA de janeiro de 2019 a agosto de 2020 foram incluídos no estudo e divididos em dois grupos com base no fato de terem ou não recebido um dreno no pós-operatório. Resultados: O grupo de drenagem apresentou escores EVA significativamente menores no dia 1, no dia 2 e no dia 3, além de alterações significativamente menores na circunferência da articulação do joelho em 3 dias de pós-operatório (P <0,05). A ADM no grupo de drenagem aumentou significativamente em 3 dias e 1 mês após a cirurgia, com uma diferença estatisticamente significativa no consumo de morfina entre os dois grupos em 3 dias (P<0,05). A incidência de náuseas e vômitos no pós-operatório(5 casos) e sangramento da ferida (1 caso) foi menor no grupo de drenagem em comparação com o grupo sem drenagem (P<0,05). Conclusão: A utilização de tubo de drenagem na UKA pode reduzir o edema articular do joelho e a dor, reduzindo o uso de opioides e facilitando as atividades funcionais iniciais da articulação do joelho. Nível de Evidência III; Estudo Comparativo Retrospectivo.

The effects of pH, surfactant, ion concentration, coformer, and molecular arrangement on the solubility behavior of myricetin cocrystals.

Pharmaceutical cocrystals are a promising technology that can be used to improve the solubility of poor aqueous compounds. The objective of this study was to systematically investigate the solubility of myricetin (MYR) cocrystals, including their kinetic solubility, thermodynamic solubility, and intrinsic dissolution rate (IDR). The effects of pH, surfactant, ion concentration, and coformers on the cocrystal solubility were evaluated. Furthermore, single crystal structures of MYR, myricetin-isonicotinamide (MYR-INM) and myricetin-caffeine (MYR-CAF) cocrystals were analyzed to discuss the possible reasons for the enhancement of cocrystal solubility from the perspective of the spatial structure. The results indicated that the kinetic solubility of MYR cocrystals was modulated by pH and cocrystal coformer (CCF) ionization in buffer solution, while it primarily depended on the CCF solubility in pure water. In addition, the solubility of MYR cocrystals was increased in a concentration dependent fashion by the surfactant or ion concentration. The thermodynamic solubility of MYR-INM (1:3) cocrystals decreased with the increases of the pH value of the dissolution media. The IDR of MYR cocrystals was faster than that of MYR in the same medium and extremely fast in pH 4.5 buffer. The improved solubility of MYR cocrystals was probably related to the alternate arrangements of MYR and INM/CAF molecules and increased intermolecular distance. The present study provides some references to investigate the solubility behavior of pharmaceutical cocrystals.

Development of daidzein nanosuspensions: Preparation, characterization, in vitro evaluation, and pharmacokinetic analysis.

The purpose of this investigation was to improve the solubility and oral bioavailability of daidzein via preparing nanosuspensions (NS) with steric stabilizers, electrostatic stabilizers, or a combination of both. Based on particle size and zeta potential, daidzein NS stabilized by HP-ß-CD, soy lecithin, HP-ß-CD + soy lecithin, TPGS, TPGS + SBE-ß-CD, SDS, or HPMC E5 + SDS were generated and characterized by scanning electron microscopy, powder X-ray diffraction, and Fourier transform-infrared spectroscopy. In addition, the stability, cytotoxicity, solubility, dissolution, and pharmacokinetics of NS were evaluated. The resulting daidzein NS were physically stable and biocompatible and presented as regular shapes with homogenous particle sizes of 360-600 nm and decreased crystallinity. Due to the increased solubility and dissolution rate, the oral bioavailability of daidzein NS in rats was 1.63-2.19 times greater than that of crude daidzein. In particular, among the investigated seven daidzein NS formulations, daidzein NS prepared with the costabilizers HPMC E5 + SDS is an optimal formulation for increased daidzein bioavailability. The present study proposes that the combined usage of steric and electrostatic stabilizers is a promising strategy for improving the bioavailability of water-insoluble flavonoid compounds by an NS approach.

Graphene-based biosensors for the detection of prostate cancer protein biomarkers: a review.

Prostate cancer (PC) is the sixth most common cancer type in the world, which causes approximately 10% of total cancer fatalities. The detection of protein biomarkers in body fluids is the key topic for the diagnosis and prognosis of PC. Highly sensitive screening of PC is the most effective approach for reducing mortality. Thus, there are a growing number of literature that recognizes the importance of new technologies for early diagnosis of PC. Graphene is playing an important role in the biosensor field with remarkable physical, optical, electrochemical and magnetic properties. Many recent studies demonstrated the potential of graphene materials for sensitive detection of protein biomarkers. In this review, the graphene-based biosensors toward PC analysis are mainly discussed in two groups: Firstly, novel biosensor interfaces were constructed through the modification of graphene materials onto sensor surfaces. Secondly, ingenious signal amplification strategies were developed using graphene materials as catalysts or carriers. Graphene-based biosensors have exhibited remarkable performance with high sensitivities, wide detection ranges, and long-term stabilities.

An ultrasensitive electrochemical biosensor for the detection of mecA gene in methicillin-resistant Staphylococcus aureus.

Electrochemical DNA biosensor has unique advantages for on-site pathogenic microorganism detection, yet the detection of long DNA towards genome DNA (gDNA) analysis remains challenge. In this work, we report a novel electrochemical biosensor for the ultrasensitive analysis of mecA DNA on methicillin-resistant Staphylococcus aureus (MRSA) genome, using a multi-signal probes (MSP) system. The MSP consists of 7 biotin-labelled signal probes that will combine to the target DNA in a prehybridization step, and then the complex will be captured by a DNA tetrahedron structure probe (TSP) on the electrode surface. Then, after the introduction of the streptavidin-labelled HRP enzyme, a catalysis current signal is detected that is found to be corresponding to the concentration of the target DNA. MSP in this work plays a critical role not only for the signal amplification through bringing 7 biotins, but also dramatically improves the accessibility of the target sequence embedded in the double-strand DNA molecules and complex second structures. The 3-D DNA TSP here provides steady support and optimized surface density for the very "large" complex of MSP system and gDNA, as a base of the capture probe. Finally, as low as 10fM synthetic target DNA was successfully detected, which is at least 3 magnitudes lower than that using single signal probe. Most importantly, we demonstrated the practicability of our analysis method by analyzing a 57fM MRSA gDNA sample showing excellent selectivity, and the reliability of the analysis was also demonstrated by digital PCR.

PCR-Free Colorimetric DNA Hybridization Detection Using a 3D DNA Nanostructured Reporter Probe.

A "sandwich-like" biosensor was developed on the basis of the magnetic bead platform for sensitive detection of breast cancer 1 (BRCA1) DNA. In the present study, a tetrahedron-structured reporter probe (TSRP) was designed, in which 3 vertices of the tetrahedron were labeled with digoxin (Dig), and the other one was labeled with a detection probe. TSRP here provided accurate enzyme loading and well-organized spatial arrangement for optimized signal amplification. The detection limit of this biosensor was as low as 10 fM, which is at least 4 orders of magnitude lower than that of the single DNA probe (100 pM), and the signal gain was 2 times higher than the analysis using three one-dimensional (1D) reporter probes. We could distinguish DNA sequences with only 1 base mismatch, and the performance of our TSRP biosensor was proven to be equally good in both PCR products and real fetal calf serum (FCS) sample as in buffer. We believe this work provided a novel avenue for the development of signal amplification strategies.

Effect of MTHFR A1298C and MTRR A66G Genetic Mutations on Homocysteine Levels in the Chinese Population: A Systematic Review and Meta-analysis.

BACKGROUND AND OBJECTIVES: The Chinese population typically has inadequate folate intake and no mandatory folic acid fortification. Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) are the two key regulatory enzymes in the folate/homocysteine (Hcy) metabolism. Hcy has been implicated in the pathogenesis of cardiovascular disease. We conducted a meta-analysis to assess whether the MTHFR gene A1298C and the MTRR gene A66G polymorphisms affect Hcy levels in the Chinese population. METHODS: This analysis included 13 studies with Hcy levels reported as one of the study measurements. Summary estimates of weighted mean differences and 95% confidence intervals (CIs) were obtained using random-effect models. RESULTS: Overall, there were no significant differences in Hcy concentrations between participants with the MTHFR 1298 CC (12 trials, n = 129), AA (n = 2166; ß, -0.51 µmol/L; 95%CI: -2.14, 1.11; P = 0.53), or AC genotype (n = 958; ß, 0.55 µmol/L; 95%CI: -0.72, 1.82; P = 0.40). Consistently, compared to those with the MTRR 66 GG genotype (6 trials, n = 156), similar Hcy concentrations were found in participants with the AA (n = 832; ß, -0.43 µmol/L; 95%CI: -1.04, 0.17; P = 0.16) or AG (n =743; ß, -0.57 µmol/L; 95%CI: -1.46, 0.31; P = 0.21) genotype. Similar results were observed for the dominant and recessive models. CONCLUSIONS: Neither the MTHFR A1298C polymorphism nor the MTRR A66G polymorphism affects Hcy levels in the Chinese population.

Quantification of plasmid DNA reference materials for Shiga toxin-producing Escherichia coli based on UV, HR-ICP-MS and digital PCR.

BACKGROUND: The accuracy and metrology traceability of DNA quantification is becoming a critical theme in many fields, including diagnosis, forensic analysis, microorganism detection etc. Thus the research of DNA reference materials (RMs) and consistency of DNA quantification methods has attracted considerable research interest. RESULTS: In this work, we developed 3 plasmid candidate RMs, containing 3 target genes of Escherichia coli O157:H7 (E. coli O157:H7) and other Shiga toxin-producing Escherichia coli (STEC): stx1, stx2, and fliC (h7) respectively. Comprehensive investigation of the plasmid RMs was performed for their sequence, purity, homogeneity and stability, and then the concentration was quantified by three different methods: ultraviolet spectrophotometer (UV), high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) and digital PCR. As a routinely applied method for DNA analysis, UV was utilized for the quantification (OD260) and purity analysis for the plasmids. HR-ICP-MS quantified the plasmid DNA through analysing the phosphorus in DNA molecules. Digital PCR distributed the DNA samples onto a microarray chip containing thousands of reaction chambers, and quantified the DNA copy numbers by analysing the number of positive signals without any calibration curves needed. CONCLUSIONS: Based on the high purification of the DNA reference materials and the optimization of dPCR analysis, we successfully achieved good consistency between UV, HR-ICP-MS and dPCR, with relative deviations lower than 10 %. We then performed the co-quantification of 3 DNA RMs with three different methods together, and the uncertainties of their concentration were evaluated. Finally, the certified values and expanded uncertainties for 3 DNA RMs (pFliC, pStx1 and pStx2) were (1.60 ± 0.10) × 10(10) copies/µL, (1.53 ± 0.10) × 10(10) copies/µL and (1.70 ± 0.11) × 10(10) copies/µL respectively.Graphical abstractWe developed 3 plasmid candidate RMs, containing 3 target genes of Escherichia coli O157:H7 (E. coli O157:H7) and other Shiga toxin-producing Escherichia coli (STEC): stx1, stx2, and fliC (h7) respectively, and the quantification of three different methods (UV, dPCR, ICP) was studied.

Analysis of telomerase activity based on a spired DNA tetrahedron TS primer.

The development of sensitive telomerase biosensors is hindered by the restricted accessibility of telomere strand (TS) primer and the limited enzyme reaction space, which is mainly confined by the vertical distance. In this work, we designed an electrochemical telomerase biosensor based on a spired DNA tetrahedron TS primer (STTS). By adding a rigid dsDNA spire onto the top of the DNA tetrahedron, we successfully regulated the distance between the TS primer and the surface, and thus greatly facilitated the telomerase elongation on surface. The signal-to-noise ratio was 2 times higher than TSP without the spire structure. The limit of detection was calculated to be lower than 10 HeLa cells, which is at least 2 magnitudes lower than other surface extension-based electrochemical telomerase sensors without amplification. The practicability of STTS sensor was also demonstrated by analysing various other cell lines including cancer cells, stem cells of high telomerase activity and somatic cells of low telomerase activity.

A carbon nanotube-based high-sensitivity electrochemical immunosensor for rapid and portable detection of clenbuterol.

Carbon nanotubes have shown their unique advantages of mechanical, chemical and electronic properties in bioanalysis. We herein report a new method to efficiently and reproducibly prepare multi-walled carbon nanotubes (MWNTs)-protein sensing layers for electrochemical immunosensors. This method employs centrifugation to prepare a conjugate of MWNTs and goat anti mouse-immunoglobulin G (IgG) (secondary antibody). The conjugates were then deposited on screen-printed electrodes to form a nanostructured layer (MWNT-I layer). CLB monoclonal antibody was assembled through its binding to the secondary antibody. The MWNT-I layer-based electrodes were used for rapid and sensitive amperometric immunosensing detection of clenbuterol (CLB) in swine urine samples. Horseradish peroxidase-coupled CLB (CLB-HRP) competed with free CLB in the samples to bind the monoclonal antibody. It has shown significantly higher sensitivity and better reproducibility than the chemical conjugation method. This MWNT-based immunosensor is highly sensitive, leading to a limit of detection of 0.1 ng/mL within a rapid assay time of 16 min. Its sensitivity is at least 1 order of magnitude higher than that of a normal immunosensor (without MWNTs). The sensing device is portable with disposable screen-printed electrode, satisfactorily meeting the requirements for field detection of food security-related species.