Charge Density-Regulated Microchannel-Based Electrochemiluminescence Sensor for Hydrogen Sulfide Detection with a Highly Efficient Accumulation Strategy.

The electrochemiluminescence (ECL) intensity can be regulated by ionic current passing through the microchannel, which broadened the regulation of the ECL sensors. But in the early reported sensors, the electrostatic repulsion and steric hindrance caused few targets to approach the interface of the microchannel driven by concentration difference, which reduced the detection efficiency and prolonged the detection period. In this study, different accumulation strategies, such as a positive electric field and different polarity electric fields, were designed to accumulate targets in the microchannel. The interaction of azide groups and hydrogen sulfide served as a research model. Hydrogen sulfide can react with the negatively charged azide groups in the microchannel surface to produce positively charged amino groups, decreasing the negative charge density of the microchannel and thus altering the ionic current and ECL intensity. The accumulation of hydrogen sulfide at the microchannel tip can increase the collision probability with azide groups to improve the detection efficiency, and the integration of accumulation and reaction can shorten the detection period to 28 min. The hydrogen sulfide concentration on the microchannel tip accumulated by applying different polarity electric fields was 22.3-fold higher than that accumulated by applying a positive electric field. The selected research model broadened the application range of a microchannel-based ECL sensor and confirmed the universality of the microchannel-based ECL sensor.

[Relationship Between Cerebrovascular Reactivity and Depression in Patients With End-Stage Renal Disease].

Objective To investigate the relationship between cerebrovascular reactivity (CVR) and emotional disorders in the patients undergoing continuous hemodialysis for end-stage renal disease (ESRD).Methods The clinical data of the ESRD patients undergoing continuous hemodialysis were collected.Anxiety and depression of the patients were assessed by the Hamilton anxiety scale (HAMA) and Beck depression inventory,respectively.The cerebral hemodynamic changes during the breath holding test were monitored by transcranial Doppler sonography,and the breath-holding index (BHI) was calculated.The BHI≥0.69 and BHI<0.69 indicate normal CVR and abnormal CVR,respectively.Binary Logistic regression was employed to analyze the factors affecting the depressive state of ESRD patients.Results The group with abnormal CVR exhibited higher total cholesterol level (P=0.010),low density lipoprotein level (P=0.006),and incidence of depression (P=0.012) than the group with normal CVR.Compared with the non-depression group,the depression group displayed prolonged disease course (P=0.039),reduced body mass index (P=0.048),elevated HAMA score (P=0.001),increased incidence of anxiety (P<0.001),decreased BHI (P=0.015),and increased incidence of abnormal CVR (P=0.012).Binary Logistic regression analysis indicated anxiety as a contributing factor (OR=22.915,95%CI=2.653-197.956,P=0.004) and abnormal CVR as a risk factor (OR=0.074,95%CI=0.008-0.730,P=0.026) for depression.Conclusion Impaired CVR could pose a risk for depression in the patients with ESRD.

Protein denaturation inspired microchannel-based electrochemiluminescence sensor for formaldehyde detection.

Establishing an effective system to measure formaldehyde (HCHO) content in food is of great significance due to food safety concern. Inspired by the mechanism of HCHO-induced protein denaturation and its effect on ion/molecule transport in nanochannels, a bioinspired microchannel-based electrochemiluminescence (ECL) sensor was constructed for HCHO detection. Benefiting from the water solubility of HCHO, the molecules rapidly spread and enriched at the ethylenediamine (EDA) functionalized microchannel interface. The reaction between EDA and HCHO significantly increased the negative charge density, leading to enhanced electroosmotic flow (EOF). This enhancement resulted in ion concentration depletion at the microchannel tip and a corresponding decrease in ionic current and ECL intensity. The ECL intensity exhibited a linear dependence on the logarithm of HCHO concentration ranging from 1 pg mL-1 to 100 ng mL-1, with a detection limit of 0.26 pg mL-1(S/N = 3). The biosensor demonstrated high selectivity, successfully detecting HCHO in shrimp samples. The performance of the bioinspired sensor was confirmed through comparation with existing methods, showcasing its superior sensitivity and reliability. The bioinspired sensor provides robust technical support for HCHO detection, crucial for food safety monitoring. Additionally, the innovative combination of bionics and microchannel-based ECL technology broadens the application range of ECL sensors, marking a significant advancement in the field.

Portable Sensor for Aflatoxin B1 Based on the Regulation of Resistance of a Microchannel Using a Multimeter as Readout.

Changes in the charge density on the inner surface of the microchannel can modulate the ion concentration at the tip, thus causing changes in the resistance of the system. In this study, this property is adopted to construct a portable sensor using a multimeter and aflatoxin B1 (AFB1) is used as the model target. Initially, the cDNA/aptamer complex is modified in the microchannel. The inner microchannel surface's charge density is then altered by the recognition of the target, leading to a change in the system's resistance, which can be conveniently monitored using a multimeter. Critical parameters influencing the performance of the system are optimized. Under optimum conditions, the resistance is linearly related to the logarithm of AFB1 concentration in the range of 100 fM-10 nM and the detection limit is 46 fM (S/N = 3). The resistive measurement is separated from the recognition reaction of the target, reducing the matrix interference during the detection process. This sensor boasts high sensitivity and specificity coupled with commendable reproducibility and stability. It is applied to assay the AFB1 content successfully in an actual sample of corn. Moreover, this approach is cost-effective, user-friendly, and highly accurate.