Interfacial reactivity-modulated fluorescent metal-organic frameworks for sensitive detection of interferon-γ towards tuberculosis diagnosis.

A new aptamer-based method has been developed for interferon-γ (IFN-γ) detection by utilizing interface reactivity-modulated fluorescent metal-organic frameworks (MOFs). Specifically, the binding of IFN-γ to its aptamer decreases the interface reactivity between the biotin-labeled aptamer and the streptavidin-functionalized magnetic beads by generating significant steric effects. As a result, several biotin-labeled aptamers escape from the enrichment of magnetic beads and remain in the supernatant, which subsequently undergo the terminal deoxynucleotidyl transferase-catalyzed polymerization elongation. Along with the elongation, pyrophosphate is continuously produced as the by-product, triggering the decomposition of fluorescent MOFs to generate a remarkable fluorescent response with the excitation/emission wavelength of 610 nm/685 nm. Experimental results show that the method enables the detection of IFN-γ in the range 0.06 fM to 6 pM with a detection limit of 0.057 fM. The method also displays high specificity and repeatability with an average relative standard deviation of 2.04%. Moreover, the method demonstrates satisfactory recoveries from 96.3 to 105.5% in serum samples and excellent utility in clinical blood samples. Therefore, this work may provide a valuable tool for IFN-γ detection and is expected to be of high potential in tuberculosis diagnosis in the future.

Programmable DNA-Fueled Electrochemical Analysis of Lung Cancer Exosomes.

Molecular diagnostics devoted to discover and monitor new biomarkers is gaining increasing attention in clinical diagnosis. In this work, a programmable DNA-fueled electrochemical analysis strategy is designed for the determination of an emerging biomarker in lung cancer, PD-L1-expressing exosomes. Specifically, PD-L1-expressing exosomes are first enriched onto magnetic beads functionalized with PD-L1 antibody and are able to interact with cholesterol-modified hairpin templates. Then, programmable DNA synthesis starts from the hairpin template-triggered primer exchange reaction and generates a large number of extension products to activate the trans-cleavage activity of CRISPR-Cas12a. After that, CRISPR-Cas12a-catalyzed random cleavage boosts the degradation of methylene blue-labeled signaling strands, so electro-active methylene blue molecules can be enriched onto a cucurbit[7]uril-modified electrode for quantitative determination. Our method demonstrates high sensitivity and specificity toward electrochemical analysis of PD-L1-expressing exosomes in the range from 103 to 109 particles mL-1 with a low detection limit of 708 particles mL-1. When applied to clinical samples, our method reveals an elevated level of circulating PD-L1-expressing exosomes in lung cancer patients, especially for those at the advanced stages. Therefore, our method may provide new insight into liquid biopsy for better implementation of immunotherapy in lung cancer in the future.

Triple Signal Amplification Strategy for Ultrasensitive Determination of miRNA Based on Duplex Specific Nuclease and Bridge DNA-Gold Nanoparticles.

Abnormal expression of miRNAs always occurs in solid tumors. Thus, it is critical to sensitively and selectively detect such biomarkers for the diagnosis and prognosis of diseases. Here, we report a biosensing scheme for the determination of miRNA with triple signal amplification based on target-triggered cyclic duplex specific nuclease digestion and bridge DNA-gold nanoparticles. Electrochemical signals are recorded to present initial levels of miRNA. This method is ultrasensitive with a wide linear range of 10-17 to 10-11 M. The limit of detection is down to 6.8 aM. Moreover, the overexpression of miR-21 is confirmed in lung cancer patients by the proposed method, which is in good accordance with qRT-PCR results. In addition, the developed biosensor does not need a reverse transcription process or any thermal cycling processes. Its performance satisfies the requirement for convenient, rapid, sensitive, and specific early diagnosis of cancers. Therefore, it may have great potential utility in the near future.

Assembly of Self-Cleaning Electrode Surface for the Development of Refreshable Biosensors.

Passivation of electrode surface and tedious reconstruction of biosensing architectures have long plagued researchers for the development of electrochemical biosensors. Here, we report a novel self-cleaning electrode by modifying the commonly used working electrode with superhydrophobic and conductive nanocomposite. Owing to the superhydrophobicity and the chemical stability, the electrode avoids passivation result from both adsorption of molecules and oxidation in air. The high conductivity and the high effective area also allow the achievement of enhanced electrochemical signals. On the basis of comprehensive studies on this novel electrode, we have applied it in the fabrication of refreshable electrochemical biosensors for both electro-active and electro-inactive targets. For both cases, detection of the targets can be well performed, and the self-cleaning electrode can be refreshed by simply washing and applied for successive measurements in a long period.

Detection of microRNA: A Point-of-Care Testing Method Based on a pH-Responsive and Highly Efficient Isothermal Amplification.

Laborious and costly detection of miRNAs has brought challenges to its practical applications, especially for home health care, rigorous military medicine, and the third world. In this work, we present a pH-responsive miRNA amplification method, which allows the detection of miRNA just using a pH test paper. The operation is easy and no other costly instrument is involved, making the method very friendly. In our strategy, a highly efficient isothermal amplification of miRNA is achieved using an improved netlike rolling circle amplification (NRCA) technique. Large amounts of H+ can be produced as a byproduct during the amplification to induce significant changes of pH, which can be monitored directly using a pH test paper or pH-sensitive indicators. The degree of color changes depends on the amount of miRNA, making it possible for quantitative analysis. As an example, the method is successfully applied to quantify a miRNA (miR-21) in cancer cells. The results agree well with that from the prevalent qRT-PCR analysis. It is the first time that a paper-based point-of-care testing (POCT) is developed for the detection of miRNAs, which might promote the popularization of miRNAs working as biomarkers for diagnostic purposes.

An electrochemical biosensor for the direct detection of oxytetracycline in mouse blood serum and urine.

Oxytetracycline (OTC), a broad-spectrum antibiotic, has been extensively used as a food additive for livestock. Its extensive use has greatly increased the risk of chronic drug abuse and has also increased the risk of the resulting diseases. Therefore, in light of this emerging situation, the detection of OTC in both food and livestock is very important to reduce the risks and for diagnosis purposes . In this work, we have proposed an electrochemical aptasensor to quantify OTC. The biosensor shows considerable sensitivity and selectivity, and it can be easily operated and regenerated. Furthermore, for the first time, we have shown that an electrochemical aptasensor can be directly used to detect OTC in mouse blood serum and urine. This biosensor has the potential to aid in the analysis of residual OTC levels, as well as providing more pharmacokinetic information in the future.

Elucidating the primary mechanisms of high-intensity interval training for improved cardiac fitness in obesity.

Obesity is a global and rising multifactorial pandemic associated with the emergence of several comorbidities that are risk factors for malignant cardiac remodeling and disease. High-intensity interval training (HIIT) has gained considerable attention due to its favorable outcomes of cardiometabolic health in individuals with overweight or obese. The primary aim of this review is to discuss the fundamental processes through which HIIT improves cardiac impairment in individuals with obesity to develop viable treatments for obesity management. In this review, a multiple database search and collection were conducted from the earliest record to January 2013 for studies included the qualitative component of HIIT intervention in humans and animals with overweight/obesity related to cardiac remodeling and fitness. We attempt to integrate the main mechanisms of HIIT in cardiac remolding improvement in obesity into an overall sequential hypothesis. This work focus on the ameliorative effects of HIIT on obesity-induced cardiac remodeling with respect to potential and pleiotropic mechanisms, including adipose distribution, energy metabolism, inflammatory response, insulin resistance, and related risk profiles in obesity. In conclusion, HIIT has been shown to reduce obesity-induced risks of cardiac remodeling, but the long-term effects of HIIT on obesity-induced cardiac injury and disease are presently unknown. Collective understanding highlights numerous specific research that are needed before the safety and effectiveness of HIIT can be confirmed and widely adopted in patient with obesity.

Programmable DNA Circuit-Facilitated Determination of Circulating Extracellular Vesicle PD-L1 for Lung Cancer Diagnosis and Immunotherapy Response Prediction.

Circulating extracellular vesicle (EV) PD-L1 is correlated with the occurrence and progression of lung cancer and has great potential as a valuable diagnostic and immunotherapy predictive biomarker. In this work, we propose a fluorescent biosensing method for the sensitive and accurate determination of circulating EV PD-L1. Specifically, after the phosphatidylserine-targeting peptide-assisted magnetic enrichment, a programmable DNA circuit is designed to translate the presence of PD-L1 to the appearance of numerous duplex DNA probes on the circulating EV surface. Upon fructose treatment, these newly formed duplex DNA probes are released from the EV surface to activate the trans-cleavage activity of CRISPR/Cas12a system, which finally produces a significant fluorescence signal. Experimental results reveal that the method not only enables sensitive determination of EV PD-L1 with a detection limit of 67 particles/mL but also demonstrates the potential use in the diagnosis and immunotherapy response prediction of lung cancer in a principle-of-proof study. Therefore, the method may provide a useful tool for EV PD-L1 determination, which may provide valuable information for the precise diagnosis and personalized treatment of lung cancer patients.

The Regulatory Role of Oxygen Metabolism in Exercise-Induced Cardiomyocyte Regeneration.

During heart failure, the heart is unable to regenerate lost or damaged cardiomyocytes and is therefore unable to generate adequate cardiac output. Previous research has demonstrated that cardiac regeneration can be promoted by a hypoxia-related oxygen metabolic mechanism. Numerous studies have indicated that exercise plays a regulatory role in the activation of regeneration capacity in both healthy and injured adult cardiomyocytes. However, the role of oxygen metabolism in regulating exercise-induced cardiomyocyte regeneration is unclear. This review focuses on the alteration of the oxygen environment and metabolism in the myocardium induced by exercise, including the effects of mild hypoxia, changes in energy metabolism, enhanced elimination of reactive oxygen species, augmentation of antioxidative capacity, and regulation of the oxygen-related metabolic and molecular pathway in the heart. Deciphering the regulatory role of oxygen metabolism and related factors during and after exercise in cardiomyocyte regeneration will provide biological insight into endogenous cardiac repair mechanisms. Furthermore, this work provides strong evidence for exercise as a cost-effective intervention to improve cardiomyocyte regeneration and restore cardiac function in this patient population.

The Molecular Mechanisms Associated with Aerobic Exercise-Induced Cardiac Regeneration.

The leading cause of heart failure is cardiomyopathy and damage to the cardiomyocytes. Adult mammalian cardiomyocytes have the ability to regenerate, but this cannot wholly compensate for myocardial cell loss after myocardial injury. Studies have shown that exercise has a regulatory role in the activation and promotion of regeneration of healthy and injured adult cardiomyocytes. However, current research on the effects of aerobic exercise in myocardial regeneration is not comprehensive. This review discusses the relationships between aerobic exercise and the regeneration of cardiomyocytes with respect to complex molecular and cellular mechanisms, paracrine factors, transcriptional factors, signaling pathways, and microRNAs that induce cardiac regeneration. The topics discussed herein provide a knowledge base for physical activity-induced cardiomyocyte regeneration, in which exercise enhances overall heart function and improves the efficacy of cardiac rehabilitation.

What and How Can Physical Activity Prevention Function on Parkinson's Disease?

AIM: This study was aimed at investigating the effects and molecular mechanisms of physical activity intervention on Parkinson's disease (PD) and providing theoretical guidance for the prevention and treatment of PD. METHODS: Four electronic databases up to December 2019 were searched (PubMed, Springer, Elsevier, and Wiley database), 176 articles were selected. Literature data were analyzed by the logic analysis method. RESULTS: (1) Risk factors of PD include dairy products, pesticides, traumatic brain injury, and obesity. Protective factors include alcohol, tobacco, coffee, black tea, and physical activity. (2) Physical activity can reduce the risk and improve symptoms of PD and the beneficial forms of physical activity, including running, dancing, traditional Chinese martial arts, yoga, and weight training. (3) Different forms of physical activity alleviate the symptoms of PD through different mechanisms, including reducing the accumulation of α-syn protein, inflammation, and oxidative stress, while enhancing BDNF activity, nerve regeneration, and mitochondrial function. CONCLUSION: Physical activity has a positive impact on the prevention and treatment of PD. Illustrating the molecular mechanism of physical activity-induced protective effect on PD is an urgent need for improving the efficacy of PD therapy regimens in the future.

Challenges and countermeasures of thoracic oncology in the epidemic of COVID-19.

Since December, 2019, a 2019 novel coronavirus disease (COVID-19) infected by the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) emerged in Wuhan, Hubei province, and the epidemic situation has continued to spread globally. The epidemic spread of COVID-19 has brought great challenges to the clinical practice of thoracic oncology. Outpatient clinics need to strengthen the differential diagnosis of initial symptoms, pulmonary ground-glass opacity (GGO), consolidation, interstitial and/or interlobular septal thickening, and crazy paving appearance. In the routine of oncology, the differential diagnosis of adverse events from COVID-19 is also significant, including radiation pneumonitis, checkpoint inhibitor pneumonitis (CIP), neutropenic fever, and so on. During the epidemic, indications of transbronchial biopsy (TBB) and CT-guided percutaneous thoracic biopsy are strictly controlled. For patients who are planning to undergo biopsy operation, screening to exclude the possibility of COVID-19 should be carried out. For confirmed or suspected patients, three-level protection should be performed during the operation. Disinfection and isolation measures should be strictly carried out during the operation. At last, more attention to the protection of cancer patients and give priority to the treatment of infected cancer patients.

A target-responsive liposome activated by catalytic hairpin assembly enables highly sensitive detection of tuberculosis-related cytokine.

Here, we propose a new fluorescence method to detect tuberculosis-related cytokine by using a target-responsive liposome activated by catalytic hairpin assembly. The method combines a DNA self-assembly based amplification process with a liposome-based signal amplification process, therefore offering a very high sensitivity.

From Interface to Solution: Integrating Immunoassay with Netlike Rolling Circle Amplification for Ultrasensitive Detection of Tumor Biomarker.

Both the 3D solution and the 2D interface play important roles in bioanalysis. For the former, reactions can be carried out adequately; while for the latter, interfering substance can be eliminated simply through wash. It is a challenge to integrate the advantages of solution-based assays and the interface-based assays. Here, we report an immuno-NRCA (netlike rolling circle amplification) strategy, which integrates immunoassay with NRCA for the ultrasensitive detection of tumor biomarker, by taking the assay of a tumour marker as an example. In this strategy, immunoreactions occur on interface, while the target-induced signal amplification can be completed totally in solution. As a result, this system has the merits of both solution- and interface-based assays. The whole procedure of this novel strategy is similar to the conventional ELISA, inheriting the usability. But in comparison with ELISA, the performance is greatly improved. The detection limit can be lowered to 5.5 fg/L, making it possible to detect the target tumour marker in one drop of blood. Also, in comparison with established immuno-PCR method, which integrates immunoassay with the commonly used nucleic acid amplification approach, this system has no requirement for thermal cycler owing to the isothermal amplification, and it has the ability to retain the immunoreactivities. So, the new immunoassay method proposed in this study may have more feasible applications in the future.

A dual-signal strategy for the solid detection of both small molecules and proteins based on magnetic separation and highly fluorescent copper nanoclusters.

Recently, a variety of analytical methods for the detection of small molecules or proteins based on small molecule-protein interaction have been developed. However, these methods often focus on either small molecules or proteins. Few efforts are made to detect both of them in the same system. In this work, a dual-signal strategy for the solid detection of both small molecules and proteins based on small molecule-protein interaction is proposed by using the streptavidin-biotin couple as a model. In our strategy, magnetic nanoparticles (MNPs) are adopted for target separation, and highly fluorescent copper nanoclusters (CuNCs) are synthesized in situ to give signals. In the absence of the targets, CuNCs are associated with the MNPs and present in the precipitate under magnetic field; whereas in the presence of either streptavidin or biotin, the CuNCs will present in the supernate. By monitoring the fluorescent intensity of each, dual-signal can be obtained for the solid detection of either the protein or the small molecule. Results show that sensitive and specific detection of both streptavidin (detection limit: 0.47nM) and biotin (detection limit: 3.1nM) can be achieved. This method can be extended for the detection of other small molecule-protein couples, and thereby has the potential for biomedical and clinical applications.

Identification of Cellular MicroRNA Coupling Strand Displacement Polymerization and Nicking-Endonuclease-Based Cleavage.

A target induced recycling amplification method for the detection of cellular microRNA is reported based on strand displacement polymerization and nicking endonuclease mediated cleavage. Moreover, by utilizing silver nanoparticle-based solid-state Ag/AgCl reaction, ultrahigh sensitivity is achieved with powerful discriminating towards the identification of target microRNA. The limit of detection is as low as 70 am. This method also allows the detection of cellular microRNA by lysing cells, thus making it a powerful tool for microRNA expression profiling and disease diagnosis.

Identification of Cellular MicroRNA Coupling Strand Displacement Polymerization and Nicking-Endonuclease-Based Cleavage.

Invited for this month's cover are collaborators from a group at Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences and a group at Shanghai Tenth People's Hospital, Tongji University School of Medicine. The cover picture shows the design of an electrochemical method for cellular microRNA detection coupling strand displacement polymerization and nicking-endonuclease-mediated cleavage. Read the full text of the article at 10.1002/cplu.201500249.

A simple and general approach to assay protease activity with electrochemical technique.

Proteases are involved in a large number of serious disease processes, while the assay of proteolytic activity can be used for clinical diagnostics. In this paper we report a simple electrochemical method to assay protease activity. This method makes use of an unlabeled peptide that comprises the specific substrate domain of a protease, which can be easily operated and generalized for assay of various kinds of proteases. Specifically, the peptide is immobilized onto a gold electrode surface via the chemical adsorption of the C-terminal cysteine residue, forming a positively charged interface derived from the N-terminal cationic residue. Therefore, the positive electrochemical probes [Ru(NH3)5Cl](2+) cannot get across to the electrode to generate signal. Nevertheless, the proteolytic digestion of the peptide will decrease the number of positive charges on the electrode surface and weaken the blocking effect against the positive electrochemical species, resulting in an increased electrochemical signal. Under optimized conditions, the activity of the model protease, trypsin, can be assayed with a detection limit of 0.026 U/mL. The method may also allow the determination of trypsin activity in serum samples. Moreover, since this approach can be used for the assay of other proteases by simply changing the substrate domain of the peptide, it may have great potential in biomedical applications in the future.

Highly sensitive protein detection based on a novel probe with catalytic activity combined with a signal amplification strategy: assay of MDM2 for cancer staging.

A novel probe with catalytic activity is used for highly sensitive MDM2 detection.

An electrochemical biosensor for clenbuterol detection and pharmacokinetics investigation.

Clenbuterol is a member of ß2 adrenergic agonists, which is widely used not only as a food additive for livestocks, but also a kind of stimulant for athletes; however, the abuse of clenbuterol may pose a significant negative impact on human health. Since it is highly required to develop fast, sensitive and cost-effective method to determine clenbuterol level in the suspected urine or blood, we herein have fabricated an electrochemical biosensor for the determination of clenbuterol. Measurement of the species with the proposed biosensor can also have the advantages of simplicity, high sensitivity and selectivity. Moreover, the sensor can be directly used for clenbuterol determination in rat urine. We have further studied the pharmacokinetics of clenbuterol by using this proposed electrochemical biosensor, so a new tool to investigate pharmacokinetic is developed in this work.