With reduced background and high sensitivity, photoelectrochemistry (PEC) may be applied as an intracellular nanotool and open a new technological direction of single‐cell study. Nevertheless, the ...present palette of single‐cell tools lacks such a PEC‐oriented solution. Here a dual‐functional photocathodic single‐cell nanotool capable of direct electroosmotic intracellular drug delivery and evaluation of oxidative stress is devised by engineering a target‐specific organic molecule/NiO/Ni film at the tip of a nanopipette. Specifically, the organic molecule probe serves simultaneously as the biorecognition element and sensitizer to synergize with p‐type NiO. Upon intracellular delivery at picoliter level, the oxidative stress effect will cause structural change of the organic probe, switching its optical absorption and altering the cathodic response. This work has revealed the potential of PEC single‐cell nanotool and extended the boundary of current single‐cell electroanalysis.
An integrated photocathodic nanotool was fabricated for dual‐functional intracellular drug delivery and evaluation of cellular oxidative stress in single live cell.
Ionic current rectification (ICR) based nanopipettes allow accurate monitoring of cellular behavior in single living cells. Herein, we proposed a 30 nm nanopipette functionalized with G‐quadruplex ...DNAzyme as an efficient biomimetic recognizer for ROS generation at subcellular level via the changes of current–voltage relationship. Taking advantages of the ultra‐small tip, the nanopipette could penetrate into a single living cell repeatedly or keep measuring for a long time without compromising the cellular functions. Coupled with precision nanopositioning system, generation of ROS in mitochondria in response to cell inflammation was determined with high spatial resolution. Meanwhile, the changes of aerobic metabolism in different cell lines under drug‐induced oxidative stress were monitored continuously. We believe that the ICR‐nanopipette could be developed as a powerful approach for the study of cellular activities via electrochemical imaging in living cells.
Electrochemical imaging: An ionic current rectification (ICR) based nanopipette with a 30 nm nanotip was fabricated for continuous monitoring of aerobic metabolism processes in single living cells at subcellular level. The cells produced reactive oxygen species (ROS) in mitochondria. The inner surface of the nanopipette was functionalized with G‐quadruplex DNAzyme.
Though significant advances are made in the arena of single‐cell electroanalysis, quantification of intracellular amino acids of human cells remains unsolved. Exemplified by l‐histidine (l‐His), this ...issue is addressed by a practical electrochemical nanotool synergizing the highly accessible nanopipette with commercially available synthetic DNAzyme. The fabricated nanotools are screened before operation of a single‐use manner, and the l‐His‐provoked cleavage of the DNA molecules can be sensibly transduced by the ionic current rectification response, the intrinsic property of nanopipette governed by its interior surface charges. Regional distribution of cytosolic l‐His level in human cells is electrochemically quantified for the first time, and time‐dependent drug treatment effects are further revealed. This work unveils the possibility of electrochemistry for quantification of cytosolic amino acids of a spatial‐ and time‐based manner and ultimately enables a better understanding of amino acid‐involved events in living cells.
The solution‐to‐electrochemical single‐cell analysis of intracellular amino acids is achieved by integrating nanopipette with specific DNAzyme and exemplified by targeting l‐histidine. It allowed minimally invasive detection with high sensitivity and selectivity. Drug treatment is also probed of a spatial‐ and time‐based manner.
This work reports a plasmonic strategy capable of label-free yet amplified photoelectrochemical (PEC) immunoassay for the sensitive and specific detection of model protein p53, an important ...transcription factor that regulates the cell cycle and functions as a tumor suppressor. Specifically, on the basis of Au nanoparticles (NPs) deposited on hierarchically ordered TiO2 nanotubes (NTs), a protein G molecular membrane was used for immobilization of alkaline phosphatase (ALP) conjugated anti-p53 (ALP-a-p53). Due to the immunological recognition between the receptor and target, the plasmonic charge separation from Au NPs to the conduction band of TiO2 NTs could be influenced greatly that originated from multiple factors. The degree of signal suppression is directly associated with the target concentration, so by monitoring the changes of the plasmonic photocurrent responding after the specific binding, a new plasmonic PEC immunoassay could be tailored for label-free and amplified detection. The operating principle of this study could be extended as a general protocol for numerous other targets of interest.
•The epidemiology of depressive disorders was examined among Chinese older adults receiving primary care.•One-fifth of the older adults (20.3%) had depressive disorders but only 1.3% of the depressed ...older adults were recognized by primary care physicians.•Female gender, poor financial status, loneliness, hypertension, heart disease, chronic gastric ulcer, and arthritis were significant factors associated with depressive disorders.
In recent years, there have been increasing calls for integrating late-life mental health services into primary care in China, but data on the epidemiology of depressive disorders in older adults receiving primary care are very limited. This study examined prevalence, correlates and recognition of depressive disorders among Chinese older adults receiving primary care.
A total of 752 older patients (65+ years) were consecutively recruited from 13 primary care clinics in Wuhan, China, and interviewed with the Chinese Mini-international Neuropsychiatric Interview 5.0.
One–fifth (20.3%) of the older adults met DSM-IV criteria for depressive disorders during the month prior to the interview: 10.2% had major depression, 4.8% had dysthymia, and 5.3% had minor depressive disorder. The recognition rate of older patients with depressive disorders was 1.3% only. In multiple logistic regression analysis, factors significantly associated with depressive disorders included female gender (OR = 1.61), an education of primary school and below (OR = 1.69), poor financial status (OR = 2.44), poor or fair family relationship (OR = 1.66), loneliness (OR = 1.77), hypertension (OR = 1.91), heart disease (OR = 2.02), chronic gastric ulcer (OR = 6.01), and arthritis (OR = 3.55).
Older adults from primary care clinics of economically underdeveloped regions of China were not included.
Depressive disorders are prevalent but poorly recognized in Chinese older adults receiving treatment in primary care clinics. In order to improve the emotional well-being and health of older adults, it is time to integrate the management of common mental disorders into primary healthcare in China.
Organic bioelectronics have shown promising applications for various sensing purposes due to their significant advantages in term of high flexibility, portability, easy fabrication, and ...biocompatibility. Here, a new type of organic device, organic photo‐electrochemical transistor (OPECT), is reported, which is the combination of an organic electrochemical transistor and a photo‐electrochemical gate electrode modified with CdS quantum dots (QDs). Thanks to the inherent amplification function of the transistor, the OPECT‐based biosensor exhibits much higher sensitivity than that of a traditional biosensor. The sensing mechanism of the OPECT is attributed to the charge transfer between the photosensitive semiconductor CdS QDs and the gate electrode. In an OPECT‐based DNA sensor, target DNA is labeled with Au nanoparticles (NPs) and captured on the gate electrode, which can influence the charge transfer on the gate caused by the exciton–plasmon interactions between CdS QDs and Au NPs. Consequently, a highly sensitive and selective DNA sensor with a detection limit of around 1 × 10−15
m is realized. It is expected that OPECTs can be developed as a high‐performance platform for numerous biological detections in the future.
A novel organic photo‐electrochemical transistor (OPECT) is realized based on the combination of an organic electrochemical transistor and a photo‐electrochemical gate electrode. Due to the inherent amplification function of the transistor, a highly sensitive and selective OPECT‐based DNA sensor is obtained, which shows a detection limit of 1 × 10−15
m. The OPECT is expected to have promising applications in various bioanalyses.
Single-cell analysis (SCA) could provide in-depth understanding of cell biology yet is of great challenge. Many attempts have been made to develop novel techniques for SCA. Nanopipette-based ion ...current rectification (ICR) electroanalysis represents an emerging methodology to combat in this arena. In this review, the working rationale of ICR and its key regulation factors are discussed, followed by the sensing strategies established for SCA using illustrative examples. Future perspectives in this field are also proposed.
•Ion current rectification (ICR)-nanopipette technique for single-cell analysis (SCA) is reviewed.•The fundamentals, operation rationales, and the state of the art are discussed.•Trends and prospects of this field are presented.
Implementing green development is important to realizing a harmonious relationship between humans and nature, and has attracted the attention of governments all over the world. This paper uses the ...PMC (Policy Modeling Consistency) model to make a quantitative evaluation of 21 representative green development policies issued by the Chinese government. The research finds: firstly, the overall evaluation grade of green development is good and the average PMC index of China's 21 green development policies is 6.59. Second, the evaluation of 21 green development policies can be divided into four different grades. Most grades of the 21 policies are excellent and good; the values of five first-level indicators about policy nature, policy function, content evaluation, social welfare, and policy object are high, which indicates that the 21 green development policies in this paper are relatively comprehensive and complete. Third, most green development policies are feasible. In twenty-one green development policies, there are: one perfect-grade policy, eight excellent-grade policies, ten good-grade policies, and two bad-grade policies. Fourthly, this paper analyzes the advantages and disadvantages of policies in different evaluation grades by drawing four PMC surface graphs. Finally, based on the research findings, this paper puts forward suggestions to optimize the green development policy-making of China.
Evaluating the level of green development is of great significance to better implement the concept of green development. By constructing an evaluation index system for green development, this paper ...comprehensively uses the entropy weight Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) method and coefficient of variation method to evaluate the green development level of 30 provinces in China from 2010 to 2019 and analyzes the regional differences of green development in China. The research findings are as follows: First, the level of green development in China is low but shows a slow rise trend, from 2010 to 2019; China's green development level rises from 0.274 to 0.317, an increase of 15.7%. Secondly, regional differences of green development in China are obvious, with the level ranking from high to low as eastern, western, and central regions. Third, regional differences in China's green development first widen and then narrow, with the variation coefficient of green development in 30 provinces and eastern, central, and western regions of China showing an inverted U-shaped trend of first increasing and then decreasing. Fourth, the regional difference of green development in eastern China is largest, followed by western China, and the smallest is central China. Finally, based on research findings, relevant policy recommendations are put forward.
Photoelectrochemical (PEC) bioanalysis is a newly developed methodology that provides an exquisite route for innovative biomolecular detection. Quantum dots (QDs) are semiconductor nanocrystals with ...unique photophysical properties that have attracted tremendous attentions among the analytical community. QDs-based PEC bioanalysis comprises an important research hotspot in the field of PEC bioanalysis due to its combined advantages and potentials. Currently, it has ignited increasing interests as demonstrated by increased research papers. This review aims to cover the most recent advances in this field. With the discussion of recent examples of QDs-PEC bioanalysis from the literatures, special emphasis will be placed on work reporting on fundamental advances in the signaling strategies of QDs-based PEC bioanalysis from 2013 to now. Future prospects in this field are also discussed.
•Quantum-dot-based photoelectrochemical bioanalysis is reviewed.•Fundamental advances in the signaling strategies are summarized.•Important works are highlighted as representative examples.•Future prospects in this field are also discussed.
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