Universal Dynamic DNA Assembly-Programmed Surface Hybridization Effect for Single-Step, Reusable, and Amplified Electrochemical Nucleic Acid Biosensing

The traditional sensitive electrochemical biosensors are commonly confronted with the cumbersome interface operation and washing procedures and the inclusion of extra exogenous reagents, which impose the challenge on the detection simplicity, reliability, and reusability. Herein, we present the proof-of-principle of a unique biosensor architecture based on dynamic DNA assembly programmed surface hybridization, which confers the single-step, reusable, and enzyme-free amplified electrochemical nucleic acid analysis. To demonstrate the fabrication universality three dynamic DNA assembly strategies including DNA-fueled target recycling, catalytic hairpin DNA assembly, and hybridization chain reaction were flexibly harnessed to convey the homogeneous target recognition and amplification events into various DNA scaffolds for the autonomous proximity-based surface hybridization. The current biosensor architecture features generalizability, simplicity, low cost, high sensitivity, and specificity over the traditional nucleic acid-related amplified biosensors. The lowest detection limit of 50 aM toward target DNA could be achieved by hybridization chain reaction-programmed surface hybridization. The reliable working ability for both homogeneous solution and heterogeneous inteface facilitates the target analysis with a robust reliability and reproducibility, also making it to be readily extended for the integration with the kinds of detecting platforms. Thus, it may hold great potential for the biosensor fabrication served for the point-of-care applications in resource constrained regions

Demographic, typing and clinical profiles with single HAdV infection cases in this study.

<p>Demographic, typing and clinical profiles with single HAdV infection cases in this study.</p

Molecular Typing and Epidemiology Profiles of Human Adenovirus Infection among Paediatric Patients with Severe Acute Respiratory Infection in China

<div><p>Background</p><p>Human adenoviruses (HAdVs) have been recognised as pathogens that cause a broad spectrum of diseases. The studies on HAdV infection among children with severe acute respiratory infection (SARI) are limited.</p><p>Objective</p><p>To investigate the prevalence, epidemiology, and genotype of HAdV among children with SARI in China.</p><p>Study Design</p><p>Nasopharyngeal aspirates (NPAs) or induced sputum (IS) was collected from hospitalised children with SARIs in Beijing (representing Northern China; n = 259) and Zhejiang Province (representing Eastern China; n = 293) from 2007 to 2010. The prevalence of HAdV was screened by polymerase chain reaction (PCR), followed by sequence typing of PCR fragments that targeted the second half of the hexon gene. In addition, co-infection with other human respiratory viruses, related epidemiological profiles and clinical presentations were investigated.</p><p>Results and Conclusions</p><p>In total, 76 (13.8%) of 552 SARI patients were positive for HAdV, and the infection rates of HAdV in Northern and Eastern China were 20.1% (n = 52) and 8.2% (n = 24), respectively. HAdV co-infection with other respiratory viruses was frequent (infection rates: Northern China, 90.4%; Eastern China, 70.8%). The peak seasons for HAdV-B infection was winter and spring. Additionally, members of multiple species (Human mastadenovirus B, C, D and E) were circulating among paediatric patients with SARI, of which HAdV-B (34/52; 65.4%) and HAdV-C (20/24, 83.3%) were the most predominant in Northern and Eastern China, respectively. These findings provide a benchmark for future epidemiology and prevention strategies for HAdV.</p></div

Seasonal distribution of HAdV infection.

<p>*, also contain one HAdV-D (HAdV-37) and one HAdV-E (HAdV-4)</p><p>**, indicated the statistically difference of the HAdV infection rate among four seasons</p><p>Seasonal distribution of HAdV infection.</p

Corrosion Inhibition Studies of 8‑Hydroxyquinoline Derivatives for N80 Steel in a 1.0 M HCl Solution: Experimental, Computational Chemistry, and Quantitative Structure–Activity Relationship Studies

Twelve kinds of 8-hydroxyquinoline derivatives were synthesized and characterized. The weight loss method was used to evaluate their inhibition efficiencies (IEs) in a 1.0 M HCl solution at 333 K. The results showed that the alkyl chain length, heteroatoms (S, N, and O), and number of benzene rings significantly affect the IE. Herein, the IE of 5-[(dodecylthio)methyl]-8-quinolinol reached 98.71%. Meanwhile, the potentiodynamic polarization results indicated that all 8-hydroxyquinoline derivatives were mixed-type inhibitors. Electrochemical impedance spectroscopy results revealed that 8-hydroxyquinoline derivatives can increase polarization resistance, supporting their adsorption on the N80 steel surface. Moreover, according to density functional theory (DFT), the frontier orbital distribution and quantum chemical parameters (EHOMO, ELUMO, dipole moment μ, etc.) were calculated, and the results confirmed that the substituents of protonated 8-hydroxyquinoline derivatives significantly influenced the frontier orbital distribution. Molecular dynamics simulation illustrated that all protonated 8-hydroxyquinoline derivatives were adsorbed parallel to the Fe(110) surface, and the interaction energy (Eint) evidenced that the molecular size would affect their strength of adsorption on the Fe(110) surface. The linear and nonlinear quantitative structure–activity relationship models were established by linear regression (LR) methods and BP neural networks (NN), respectively. The LR model was established by using Eint and μ, and the coefficient of determination (R2) was 0.934. In addition, the nonlinear NN model was obtained according to IE and all parameters (DFT parameters and Eint). Then, the two calculation inhibition efficiencies (IEcal) were obtained from the LR and NN models, and the R2 values of the linear correlation between the IEcal and the experimental IE were 0.940 and 0.951, respectively. In addition, the IE of the tested inhibitor was 51.86% and the IEcal values predicted by the LR and NN models were 52.68% and 53.06%, respectively. Our results demonstrate that both the LR and NN models have good fits and predictive ability

Phylogenetic analysis of HAdV based on the partial hexon gene.

<p>The phylogenetic tree was constructed by the neighbour-joining method, and bootstrap values were determined by 1000 replications in MEGA5.0. (Prefix-N: samples from Northern China; Prefix-E: samples from Eastern China; ■, sequences of the reference strains of HAdV-A cut from genomes found in GenBank; ●, sequences of reference strains of HAdV-B; ▼, sequences of reference strains of HAdV-C; Δ, sequences of reference strains of HAdV-D; ○, sequence of reference strain of HAdV-E; ◆, sequences of reference strains of HAdV-F.</p

Genotype profiles and co-infection of HAdV.

<p>*, indicated the statistically difference of the HAdV infection rate between the Northern and Eastern China.</p><p>Genotype profiles and co-infection of HAdV.</p

Demographic data in this study.

<p>Demographic data in this study.</p

Age distribution of HAdV infection.

<p>*, also contain one HAdV-D (HAdV-37)</p><p>* *, also contain one HAdV-E (HAdV-4)</p><p>*** indicated the statistically difference of the HAdV infection rate among four age groups</p><p>Age distribution of HAdV infection.</p