Micronano Synergetic Three-Dimensional Bioelectronics: A Revolutionary Breakthrough Platform for Cardiac Electrophysiology.

Cardiovascular diseases (CVDs) are the leading cause of mortality and therefore pose a significant threat to human health. Cardiac electrophysiology plays a crucial role in the investigation and treatment of CVDs, including arrhythmia. The long-term and accurate detection of electrophysiological activity in cardiomyocytes is essential for advancing cardiology and pharmacology. Regarding the electrophysiological study of cardiac cells, many micronano bioelectric devices and systems have been developed. Such bioelectronic devices possess unique geometric structures of electrodes that enhance quality of electrophysiological signal recording. Though planar multielectrode/multitransistors are widely used for simultaneous multichannel measurement of cell electrophysiological signals, their use for extracellular electrophysiological recording exhibits low signal strength and quality. However, the integration of three-dimensional (3D) multielectrode/multitransistor arrays that use advanced penetration strategies can achieve high-quality intracellular signal recording. This review provides an overview of the manufacturing, geometric structure, and penetration paradigms of 3D micronano devices, as well as their applications for precise drug screening and biomimetic disease modeling. Furthermore, this review also summarizes the current challenges and outlines future directions for the preparation and application of micronano bioelectronic devices, with an aim to promote the development of intracellular electrophysiological platforms and thereby meet the demands of emerging clinical applications.

Health risk analysis of nitrate in groundwater in Shanxi Province, China: A case study of the Datong Basin.

In order to identify and effectively control the impact of NO3- pollution on human health, on the basis of investigation, sampling, analysis and testing, statistical analysis software (SPSS19), groundwater pollution analysis software, Nemera comprehensive index method, correlation analysis method and human health risk assessment model are applied for analysis and research. The results indicate that the groundwater in the study area is mainly Class II water, with overall good water quality. The main influencing factors for producing Class IV are NO3-, Fe, F- and SO42-. The use of agricultural fertilizers is the main source of NO3- exceeding standards in groundwater in this area. There are significant differences in the health hazards caused by NO3- pollution in groundwater among different populations, and infants and young children are more susceptible to nitrate pollution. The division of pollution areas and high-risk groups plays an important guiding role in preventing health risks. The new achievements will help people improve their awareness of risk prevention, caring for the environment, respecting nature and implementing precise policies, promoting society to step onto the track of scientific and healthy development.

Optimizing the Cell-Nanostructure Interface: Nanoconcave/Nanoconvex Device for Intracellular Recording of Cardiomyocytes.

Nanostructures are powerful components for the development of high-performance nanodevices. Revealing and understanding the cell-nanostructure interface are essential for improving and guiding nanodevice design for investigations of cell physiology. For intracellular electrophysiological detection, the cell-nanostructure interface significantly affects the quality of recorded intracellular action potentials and the application of nanodevices in cardiology research and pharmacological screening. Most of the current investigations of biointerfaces focus on nanovertical structures, and few involve nanoconcave structures. Here, we design both nanoconvex and nanoconcave devices to perform intracellular electrophysiological recordings. The amplitude, signal-to-noise ratio, duration, and repeatability of the recorded intracellular electrophysiological signals provide a multifaceted characterization of the cell-nanostructure interface. We demonstrate that devices based on both convex and concave nanostructures can create tight coupling, which facilitates high-quality and stable intracellular recordings and paves the way for precise electrophysiological study.

Experimental demonstration of the quantum noise randomized cipher based on cascaded phase shift keying without a high-level digital-to-analog converter.

To break the dependence on a high-speed and high-resolution digital-to-analog converter (DAC) in the traditional quantum noise randomized cipher (QNRC), a practical DAC-free modulation scheme based on cascaded phase-shift keying (PSK) is proposed and demonstrated by a proof-of-concept experiment. By employing seven cascaded phase modulators (PMs) driven by designed electrical voltage signals, a 128 PSK-QNRC system is achieved with a transmission rate of 10 Gbaud/s and a transmission distance more than 50 km, which eliminates the need for a DAC on the transmitter side. The bit error rate (BER) performance of the proposed scheme is compared to that of a traditional scheme based on an arbitrary waveform generator (AWG) with a sampling rate of 25 GSa/s. The results show that compared to a traditional scheme, the power penalties of the proposed scheme are -1.8d B, 0.9 dB, and 1 dB, respectively, at the rates of 10, 5, and 2.5 Gbps. In other words, the BER performance of the proposed scheme is close to the traditional scheme at a low transmission rate, but better than that of the traditional scheme at a high transmission rate, where the sampling rate of the DAC is not high enough to generate a complete waveform. This work greatly enhances the security of a QNRC system.

Broadband frequency modulation signal downconversion using a monolithic integrated mutual injection laser.

We propose a new, to the best of our knowledge, broadband signal downconversion scheme implemented by a monolithic integrated mutual injection laser. A mathematical derivation, simulation, and experimental verification are carried out. Because the period-one oscillation frequency can be selectively operated on a large scale by controlling the current on the integrated laser, the tuning downconversion range is realized without changing the experimental equipment. The experiment verifies that the downconversion of the linear frequency modulation signal with a bandwidth of 0.5 GHz from the center frequency of 18.75 to 0.85 GHz, and the spurious-free dynamic range (SFDR) has reached 71.7d B/H z 2/3. Compared with the scheme based on discrete components, the system has no electric local oscillator or external modulator, which provides a method for radar signal downconversion.

The triglyceride-glucose index as a potential protective factor for hypertrophic obstructive cardiomyopathy without diabetes: evidence from a two-center study.

OBJECTIVE: This study aimed to investigate the relationship between the TyG (Triglyceride-glucose index) and the prognosis of patients with HOCM (hypertrophic obstructive cardiomyopathy) without diabetes. RESEARCH DESIGN AND METHODS: A total of 713 eligible patients with HOCM were enrolled in this study and divided into two groups based on treatment: an invasive treatment group (n = 461) and a non-invasive treatment group (n = 252). The patients in both two groups were then divided into three groups based on their TyG index levels. The primary endpoints of this study were Cardiogenic death during long-term follow-up. Kaplan-Meier analysis was used to study the cumulative survival of different groups. Restricted cubic spline was used to model nonlinear relationships between the TyG index and primary endpoints. Myocardial perfusion imaging/Myocardial metabolic imaging examinations were performed to assess glucose metabolism in the ventricular septum of the HOCM patients. RESULTS: The follow-up time of this study was 41.47 ± 17.63 months. The results showed that patients with higher TyG index levels had better clinical outcomes (HR, 0.215; 95% CI 0.051,0.902; P = 0.036, invasive treatment group; HR, 0.179; 95% CI 0.063,0.508; P = 0.001, non-invasive treatment group). Further analysis showed that glucose metabolism in the ventricular septum was enhanced in HOCM patients. CONCLUSIONS: The findings of this study suggest that the TyG index may serve as a potential protective factor for patients with HOCM without diabetes. The enhanced glucose metabolism in the ventricular septum of HOCM patients may provide a potential explanation for the relationship between the TyG index and HOCM prognosis.

Four-channel all-optical wavelength conversion unit based on nonlinear effect of three-section monolithically integrated semiconductor lasers.

A simple and highly efficient four-channel all-optical wavelength conversion based on four-wave mixing effect of the directly modulated three-section monolithically integrated semiconductor laser is proposed and experimentally investigated. For this wavelength conversion unit, the spacing of the wavelength can be adjusted by tuning the bias current of the lasers and setting it to be 0.4 nm (50 GHz) as a demonstration is this work. A 50 Mbps 16-QAM signal centers at 4-8 GHz is experimentally switched to a targeted path. Up- or downconversion depends on a wavelength-selective switch, and the conversion efficiency can reach up to -2 to 0 dB. This work provides a new technology for photonic radio-frequency switching matrix and contributes to the integrated implementation of satellite transponders.

Simple multi-band linearly frequency-modulated signal generation with a multiplying bandwidth based on a gain-switching laser.

Multi-band linearly frequency-modulated (LFM) signal generation with a multiplying bandwidth is proposed and experimentally demonstrated. It is a simple photonics method based on the gain-switching state in a distributed feedback semiconductor laser without a complex external modulator and high-speed electrical amplifiers. With N comb lines, the carrier frequency and bandwidth of generated LFM signals are N times those of the reference signal. (N is the number of comb lines.) The number of bands and time-bandwidth products (TBWPs) of the generated signals could be easily adjusted by tuning the reference signal from an arbitrary waveform generator. Three-band LFM signals with carrier frequencies ranging from the X-band to K-band are given as an example, and the TBWP up to 20000. The results of auto-correlations of the generated waveforms are also given.

High-purity linearly frequency-modulated signal generation based on the integrated semiconductor laser subject to the dynamical optoelectrical feedback.

A novel photonic method of linearly frequency-modulated (LFM) signal generation with high purity based on the monolithically integrated semiconductor laser (MISL) subject to the dynamical optoelectrical feedback is proposed and demonstrated in this paper. In this approach, the MISL is firstly operated in period-one state. By introducing the dynamical optoelectrical feedback to modulate the MISL, the generated LFM signals would be constantly optimized as long as the delay of the feedback loop is matched with the repetition period of the LFM signal. In this system, no additional high-speed external modulator, high-frequency electrical LFM oscillator are required, highly simplifying the framework and reducing the power consumption. In the current proof-of-concept experiment, one LFM signal with the bandwidth as large as 5.6 GHz is generated and the corresponding frequency comb contrast can be drastically improved by 51 dB. Furthermore, the effect of the delay mismatch is also discussed in this paper.

Causal effects of genetically predicted type 2 diabetes mellitus on blood lipid profiles and concentration of particle-size-determined lipoprotein subclasses: A two-sample Mendelian randomization study.

Background: Observational studies have shown inconsistent results of the associations between type 2 diabetes mellitus (T2DM) and blood lipid profiles, while there is also a lack of evidence from randomized controlled trials (RCTs) for the causal effects of T2DM on blood lipid profiles and lipoprotein subclasses. Objectives: Our study aimed at investigating the causal effects of T2DM on blood lipid profiles and concentration of particle-size-determined lipoprotein subclasses by using the two-sample Mendelian randomization (MR) method. Methods: We obtained genetic variants for T2DM and blood lipid profiles including high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG), and total cholesterol (TC) from international genome-wide association studies (GWASs). Two-sample MR method was applied to explore the potential causal effects of genetically predicted T2DM on blood lipid profiles based on different databases, respectively, and results from each MR analysis were further meta-analyzed to obtain the summary results. The causal effects of genetically predicted T2DM on the concentration of different subclasses of lipoproteins that are determined by particle size were also involved in MR analysis. Results: Genetically predicted 1-unit higher log odds of T2DM had a significant causal effect on a higher level of TG (estimated ß coefficient: 0.03, 95% confidence interval [CI]: 0.00 to 0.06) and lower level of HDL-C (estimated ß coefficient: -0.09, 95% CI: -0.11 to -0.06). The causality of T2DM on the level of TC or LDL-C was not found (estimated ß coefficient: -0.01, 95% CI: -0.02 to 0.01 for TC and estimated ß coefficient: 0.01, 95% CI: -0.01 to 0.02 for LDL-C). For different sizes of lipoprotein particles, 1-unit higher log odds of T2DM was causally associated with higher level of small LDL particles, and lower level of medium HDL particles, large HDL particles, and very large HDL particles. Conclusion: Evidence from our present study showed causal effects of T2DM on the level of TG, HDL-C, and concentration of different particle sizes of lipoprotein subclasses comprehensively, which might be particularly helpful in illustrating dyslipidemia experienced by patients with T2DM, and further indicate new treatment targets for these patients to prevent subsequent excessive cardiovascular events from a genetic point of view.

Association Between Thyroid Dysfunction and Incidence of Atrial Fibrillation in Patients With Hypertrophic Obstructive Cardiomyopathy.

Objective: To explore the correlation between the incidence of atrial fibrillation (AF) and thyroid dysfunction in patients with hypertrophic obstructive cardiomyopathy (HOCM). Methods: Thyroid function testing in 755 consecutive patients with HOCM were examined at the National Center for Cardiovascular Diseases (China) from October 2009 to December 2013. Patients were divided into four groups according to the TSH levels: TSH<0.55 mIU/L(n=37)、0.55~2.49 mIU/L (n=490)、2.50~9.9 mIU/L (n=211) and >10.00mIU/L(n=17). Results: A total of 107 patients were diagnosed with AF (14%).(1) Compared to HOCM patients without AF,HOCM patients with AF have older age (P<0.001), higher NT-proBNP (P=0.002), higher Cr (P=0.005), larger left atrial diameter(P=0.001), lower FT3 (P=0.046), higher FT4 (P=0.004).(2) In the four groups according to the TSH levels: TSH<0.55 mIU/L, 0.55~2.49mIU/L, 2.50~9.9mIU/L and ≥10.00mIU/L, the incidence of AF was 27.02%(10/37),10.20%(50/490), 19.43%(41/211), and 35.29%(6/17), respectively. Both high and low TSH levels were associated with an increased incidence of AF. After adjusting for the common risk factor (age, NT-proBNP, and so on), stepwise multiple logistic regression analysis revealed that TSH levels were significantly related to AF incidence.Compared to patients with TSH 0.55~2.49 mlU/L, the adjusted odds ratio of AF for TSH<0.55, 2.50~9.99, ≥10.00 mIU/L were 1.481 (95% CI 0.485~4.518,P=0.490), 1.977 (95%CI 1.115~3.506, p=0.02), 4.301 (95%CI 1.059~17.476, P=0.041), respectively. Conclusion: Our results suggested that thyroid dysfunction was associated with an increased risk of AF in patients with HOCM.

Genetically Determined Lifestyle and Cardiometabolic Risk Factors Mediate the Association of Genetically Predicted Age at Menarche With Genetic Predisposition to Myocardial Infarction: A Two-Step, Two-Sample Mendelian Randomization Study.

Background: Observational studies have shown an association between early age at menarche (AAM) and myocardial infarction (MI) with recorded cases. In this Mendelian randomization (MR) study, we used large amounts of summary data from genome-wide association studies (GWASs) to further estimate the association of genetically predicted AAM with genetically predicated risk of MI and investigate to what extent this association is mediated by genetically determined lifestyles, cardiometabolic factors, and estrogen exposure. Methods: A two-step, two-sample MR study was performed by mediation analysis. Genetic variants identified by GWAS meta-analysis of reproductive genetics consortium (n = 182,416) were selected for genetically predicted AAM. Genetic variants identified by the Coronary ARtery DIsease Genome-wide Replication and Meta-analysis plus The Coronary Artery Disease Genetics Consortium (n = 184,305) were selected for genetically predicted risk of MI. Genetic variants from other international GWAS summary data were selected for genetically determined mediators. Results: This MR study showed that increase in genetically predicted AAM was associated with lower risk of genetically predicted MI (odds ratio 0.91, 95% confidence interval 0.84-0.98). Inverse variance weighted (IVW) MR analysis also showed that decrease in genetically predicted AAM was associated with higher genetically predicted alcohol intake frequency, current smoking behavior, higher waist-to-hip ratio, and higher levels of systolic blood pressure (SBP), fasting blood glucose, hemoglobin A1c (HbA1c), and triglycerides (TGs). Furthermore, increase in genetically predicted AAM was associated with genetically predicted longer sleep duration, higher levels of high-density lipoproteins, and older age at which hormone replacement therapy was started. The most essential mediators identified were genetically predicted current smoking behavior and levels of HbA1c, SBP, and TGs, which were estimated to genetically mediate 13.9, 12.2, 10.5, and 9.2%, respectively, with a combined mediation proportion of 37.5% in the association of genetically predicted AAM with genetically predicted increased risk of MI in an MR framework. Conclusion: Our MR analysis showed that increase in genetically predicted AAM was associated with lower genetically predicted risk of MI, which was substantially mediated by genetically determined current smoking behavior and levels of HbA1c, SBP, and TGs. Intervening on the above mediators may reduce the risk of MI.

Hypertrophic Obstructive Cardiomyopathy: Comparison of Outcomes After Myectomy or Alcohol Ablation.

Introduction and Objectives: The risk of ventricular arrhythmia and heart failure in patients with hypertrophic obstructive cardiomyopathy (HOCM) is much higher than that in the general population. More and more pieces of evidence showed that HOCM is the leading cause of sudden cardiac death in young people. We reported our experience in a study, comparing surgical myectomy, alcohol septal ablation (ASA), and medical therapy. Methods: The original cohort included 965 consecutive patients with HOCM. The patients were divided into three groups according to treatment strategies: myectomy group (n = 502), ASA group (n = 138), and medical treatment group (n = 325). The median follow-up duration was 42.99 ± 18.32 months, and the primary endpoints were all-cause mortality and heart transplantation. Results: Both in short- and long-term observations, surgical myectomy reduced the left ventricular outflow tract (LVOT) gradients more effectively (7 days, 16.15 ± 12.07 mmHg vs. 42.33 ± 27.76 mmHg, p < 0.05; 1 year, 14.65 ± 13.18 mmHg vs. 41.17 ± 30.76 mmHg, p < 0.05). Among the three groups, the patients in the medical treatment group were at a higher risk of mortality and cardiac transplantation (vs. the myectomy group, p < 0.001 by log-rank test; vs. the alcohol septal ablation group, p = 0.017 by log-rank test), and the myectomy group shows a lower risk of reaching the primary endpoint than the two other groups. In the multivariate Cox regression analysis, previous atrial fibrillation (AF), N terminal pro B type natriuretic peptide (NT-pro-BNP), and surgical myectomy predicted an HOCM prognosis. However, the impact of surgical myectomy on HOCM prognosis seems to be limited to the <56 years group. Conclusions: The patients with medical treatments seemed to suffer from the highest risk of achieving an all-cause mortality and the endpoint of heart transplantation. In the long-term survival and clinical outcome, myectomy seemed better than alcohol septal ablation, especially the younger patients. Due to the less-controllable degree, periprocedural complication frequency after alcohol septal ablation was higher, compared with myectomy. Furthermore, gradients after myectomy are lower at late follow-up. To sum up, when selecting treatment strategies, the patients should be individually evaluated by a multidisciplinary team of cardiologists and surgeons.

Assessment of causal direction between thyroid function and cardiometabolic health: a Mendelian randomization study.

BACKGROUND: Growing evidence have demonstrated that thyroid hormones have been involved in the processes of cardiovascular metabolism. However, the causal relationship of thyroid function and cardiometabolic health remains partly unknown. METHODS: The Mendelian randomization (MR) was used to test genetic, potentially causal relationships between instrumental variables and cardiometabolic traits. Genetic variants of free thyroxine (FT4) and thyrotropin (TSH) levels within the reference range were used as instrumental variables. Data for genetic associations with cardiometabolic diseases were acquired from the genome-wide association studies of the FinnGen, CARDIoGRAM and CARDIoGRAMplusC4D, CHARGE, and MEGASTROKE. This study was conducted using summary statistic data from large, previously described cohorts. Association between thyroid function and essential hypertension (EHTN), secondary hypertension (SHTN), hyperlipidemia (HPL), type 2 diabetes mellitus (T2DM), ischemic heart disease (IHD), myocardial infarction (MI), heart failure (HF), pulmonary heart disease (PHD), stroke, and non-rheumatic valve disease (NRVD) were examined. RESULTS: Genetically predicted FT4 levels were associated with SHTN (odds ratio = 0.48; 95% CI = 0.04-0.82,P = 0.027), HPL (odds ratio = 0.67; 95% CI = 0.18-0.88,P = 0.023), T2DM (odds ratio = 0.80; 95% CI = 0.42-0.86,P = 0.005), IHD (odds ratio = 0.85; 95% CI = 0.49-0.98,P = 0.039), NRVD (odds ratio = 0.75; 95% CI = 0.27-0.97,P = 0.039). Additionally, genetically predicted TSH levels were associated with HF (odds ratio = 0.82; 95% CI = 0.68-0.99,P = 0.042), PHD (odds ratio = 0.75; 95% CI = 0.32-0.82,P = 0.006), stroke (odds ratio = 0.95; 95% CI = 0.81-0.97,P = 0.007). However, genetically predicted thyroid function traits were not associated with EHTN and MI. CONCLUSIONS: Our study suggests FT4 and TSH are associated with cardiometabolic diseases, underscoring the importance of the pituitary-thyroid-cardiac axis in cardiometabolic health susceptibility.

Roles of Cardiometabolic Factors in Mediating the Causal Effect of Type 2 Diabetes on Cardiovascular Diseases: A Two-Step, Two-Sample Multivariable Mendelian Randomization Study.

Objective: The objective of this study is to investigate the roles of cardiometabolic factors (including blood pressure, blood lipids, thyroid function, body mass, and insulin sensitivity) in mediating the causal effect of type 2 diabetes (T2DM) on cardiovascular disease (CVD) outcomes. Design: Two-step, two-sample multivariable Mendelian randomization (MVMR) study. Setting: International genome-wide association study (GWAS) consortia data. Exposure: Type 2 diabetes, blood pressure: systolic blood pressure (SBP), diastolic blood pressure (DBP); blood lipids: low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC), triglycerides (TG); thyroid function: hyperthyroidism, hypothyroidism; body mass index (BMI), waist-hip-ratio (WHR), and insulin sensitivity. Main Outcomes: Cardiovascular disease includes coronary heart disease (CHD), myocardial infarction (MI), and stroke. Methods: Summary-level data for exposures and main outcomes were extracted from GWAS consortia. We used two-sample MR to illustrate the causal effect of T2DM on CVD subtypes and regression-based MVMR to quantify the possible mediation effects of cardiometabolic factors on CVD. Results: Each additional unit of log odds of T2DM increased 16% risk of CHD [odds ratio (OR): 1.16, 95% CI: 1.12-1.21], 15% risk of myocardial infarction (MI) (OR: 1.15, 95% CI: 1.10-1.20), and 10% risk of stroke (OR: 1.10, 95% CI: 1.06-1.13). In mediation analysis, SBP, DBP, and TG were found as main mediators, while the mediation effects of other cardiometabolic factors were not significant. The proportion of total effect of T2DM on CHD mediated by SBP, DBP, and TG was 16% (95% CI: 8-24%), 7% (95% CI: 1-13%) and 10% (95% CI: 2-18%), respectively. Mediation effect of SBP and DBP on MI and stroke, TG on MI was also prominent, while mediation effect of TG on stroke was not significant. The combined mediation effect of all the three mediators accounted for 29%, 26%, and 13% of the total effect of T2DM on CHD, MI, and stroke, respectively. Conclusion: Systolic blood pressure, DBP, and TG mediate a substantial proportion of the causal effect of T2DM on CVD and thus interventions on these factors might reduce the considerable excess risk of CVD among patients with T2DM.

Low-power RF signal detection with wideband range based on an optically injected optoelectronic oscillator.

A novel method to detect a low-power radio-frequency (RF) signal with ultra-wide frequency range based on an optically injected optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The optical injection to a distributed feedback (DFB) laser has the advantages of amplifying one sideband of the modulated optical signal selectively and a wide tunable frequency range. The detection upper range that reaches up to 26 GHz and can be improved theoretically. To the best of the authors' knowledge, this is the widest detection range based on an OEO. At the same time, the detection characteristics are good. The sensitivity of the system is -92 dBm and the maximum gain is 12.18 dB at 15.047 GHz. Considering the real application of the detection system, the properties such as dynamic range and performance for detecting a modulated RF signal are also investigated.

ZIF-67 MOF-derived Co nanoparticles supported on N-doped carbon skeletons for the amperometric determination of hydrogen peroxide.

ZIF-67-derived Co nanoparticles supported on N-doped carbon skeletons have been prepared from melamine foam (Co-NPs/NCs) for non-enzymatic electrochemical H2O2 detection. The synthesis of Co-NPs/NCs was demonstrated via calcination treatment using melamine foam (MF) and ZIF-67 as precursors. The experimental results show that Co-NPs/NCs composites exhibit eminent catalytic activity toward specific determination of H2O2 with high selectivity and sensitivity (252.43 and 203.88 µA mM-1 cm-2), low LOD (0.12 µM), and wide linear ranges (10-2080 and 2080-11,800 µM). The excellent performance might be ascribed to the synergetic effects of MOF and N-doped carbon skeletons. The carbon skeletons serve as a conductive bridge and provide a large specific surface area, which can facilitate electron transfer and well disperse nanoparticles. This non-enzymatic electrochemical sensor based on Co-NPs/NCs can successfully detect H2O2 secreted by living cells, indicating its great potential in the early diagnosis and pathological exploration of disease.

Development of Au-Pd@UiO-66-on-ZIF-L/CC as a self-supported electrochemical sensor for in situ monitoring of cellular hydrogen peroxide.

Integrating metal-organic frameworks (MOFs) of different components or structures together and exploiting them as electrochemical sensors for electrochemical sensing has aroused great interest. Furthermore, the incorporation of noble metals with MOFs is conducive to the improvement of catalytic performance. In this work, Pd@UiO-66-on-ZIF-L nanomaterials were successfully synthesised onto a self-supported flexible carbon cloth (Pd@UiO-66-on-ZIF-L/CC) through a novel strategy called MOF-on-MOF. Then, Au nanoparticles were electrodeposited onto Pd@UiO-66-on-ZIF-L/CC to obtain Au-Pd@UiO-66-on-ZIF-L/CC, which can serve as an excellent electrocatalyst for the reduction of hydrogen peroxide (H2O2). The obtained flower-like Pd@UiO-66-on-ZIF-L/CC hybrid MOF changes the structure of the monomeric MOF alone and adds more attachment sites. The synergy of the bimetals greatly improved the catalytic performance of the as-developed sensor. Electrochemical experiment results show that the proposed sensor based on Au-Pd@UiO-66-on-ZIF-L/CC has an extended linear range from 1 µM to 19.6 mM with a sensitivity of 390 µA mM-1 cm-2, and a low limit of detection (LOD) of 21.2 nM (S/N = 3). Moreover, it has good anti-interference, reproducibility, repeatability and excellent stability. Furthermore, the real-time in situ detection of H2O2 secreted from human adenocarcinomic alveolar basal epithelial cells (A549 cells) was achieved by culturing cells on Au-Pd@UiO-66-on-ZIF-L/CC, which indicates the potential of the sensor for applications in cancer pathology. Both the synthesis strategy and the sensor design provide new methods and ideas for the production of ultrasensitive H2O2 electrochemical sensors.

Ultra simple low-power RF signal detection based on an optoelectronic feedback DFB laser.

An ultra simple and low cost method to detect low-power RF signal is proposed and experimentally demonstrated based on optoelectronic feedback DFB semiconductor laser. To our knowledge, according to public reports, this is the simplest photonics-assisted method which avoids using high sensitive optical modulators and narrow bandwidth optical filters. The RF signal, which matches the oscillation mode at the relaxation oscillation peak of the DFB laser, is amplified based on optoelectronic feedback. The RF signal from 1 to 4.5 GHz can be detected by adjusting the frequency of relaxation oscillation which is related to the laser bias current. The system provides a maximum gain of 15 dB for the low-power RF signal. The sensitivity of the system can reach up to as high as -97 dBm. Considering the real application of the detection system, the properties like dynamic range, resistance to large signals and performance for detecting modulated RF signal are also investigated.

A Prussian blue-doped RGO/MXene composite aerogel with peroxidase-like activity for real-time monitoring of H2O2 secretion from living cells.

Herein, we develop a novel 3D composite aerogel (3D PB/GMA) and apply it to the real-time monitoring of H2O2 secretion from living cells. The 3D PB/GMA shows an obvious porous structure and superior peroxidase-like activity. The electrochemical sensor based on 3D PB/GMA shows an excellent electrocatalytic performance towards H2O2. When applied to the real-time tracking of H2O2 secretion from living cells, it can satisfactorily distinguish cancer cell lines from normal cell lines, revealing a good application potential in pathological diagnosis.