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The article discusses the highlights of the 60th Annual Meeting of the International Society of Electrochemistry (ISE) held in Beijing, China from August 16-21, 2009. More than 1,300 researchers from various countries attended the meeting, which has a motto of "Emerging Trends and Challenges in Electrochemistry." The event featured five plenary lectures about modern electrochemistry topics. Some of these topics include biosensors, direct electron transfer and direct electrocatalysis.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths in China. Glypican-3 (GPC3) is a specific antigen related to HCC, which is widely used in clinical detection as a reliable marker of HCC. In this paper, a highly sensitive homogeneous apatasensor was designed for GPC3 detection based on fluorescence resonance energy transfer (FRET) where the GPC3 aptamer labelled gold carbon dots (AuCDs-GPC3Apt) are used as a donor and magnetic graphene oxide (Fe3O4/GO) nanosheets are used as an acceptor. A one-step hydrothermal method was used to synthesize AuCDs to provide sufficient fluorescence. The FRET phenomenon exists between AuCDs-GPC3Apt and Fe3O4/GO, which weakens the fluorescence intensity of the whole system. When the target GPC3 is added to the FRET system, the fluorescent AuCDs-GPC3Apt binds to the GPC3 and forms a folded structure, which leads to AuCDs-GPC3Apt separation from Fe3O4/GO nanosheets. The Fe3O4/GO is then magnetically separated so that the fluorescence of free labelled AuCDs-GPC3Apt is restored. Under the optimum conditions, the fluorescence recovery rate is linearly correlated with the concentration of GPC3 (5–100 ng·mL−1) and the detection limit is 3.01 ng·mL−1 (S/N = 3). This strategy shows recoveries from 98.76 to 101.29% in real human serum samples and provides an immediate and effective detection method for the quantification of GPC3 with great potential applications for early diagnosis of HCC. A sensitive homogeneous FRET-based apatasensor was designed for GPC3 detection where the AuCDs-GPC3Apt is a donor and Fe3O4/GO nanosheets are an acceptor. The GPC3 fluorescent aptasensor combines wider output range with low cost, high specificity, and good anti-interference. [ABSTRACT FROM AUTHOR]

A new epidemic of acute respiratory viral pneumonia was discovered in central China at the end of 2019. The disease was given the name coronavirus disease 2019 (COVID-19), and the virus that caused this disease was known as severe acute respiratory syndrome coronavirus (SARS-CoV-2). So far, diagnostic methods have been focused on (a) human antibody detection, (b) viral antigen detection and (c) viral gene detection, the latter using RT-PCR being the most accurate approach. In this paper, we present a summary of the COVID-19 pandemic, clinical features and epidemiology and pathogenesis. Also, we focus on the recent advances in bioanalytical diagnostic methods based on various techniques for SARS-CoV-2 sensing that have recently been published (2020–2021). Furthermore, we present the mechanisms, advantages and disadvantages of the most common biosensors for COVID-19 detection, which include optical, electrochemical and piezoelectric biosensors as well as wearable and smart nanobiosensors, immunosensors, aptasensors and genosensors. [ABSTRACT FROM AUTHOR]

The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) approach has been widely used to detect the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, instead of using it alone, clinicians often prefer to diagnose the coronavirus disease 2019 (COVID-19) by utilizing a combination of clinical signs and symptoms, laboratory test, imaging measurement (e.g., chest computed tomography scan), and multivariable clinical prediction models, including the electronic nose. Here, we report on the development and use of a low cost, noninvasive method to rapidly sniff out COVID-19 based on a portable electronic nose (GeNose C19) integrating an array of metal oxide semiconductor gas sensors, optimized feature extraction, and machine learning models. This approach was evaluated in profiling tests involving a total of 615 breath samples composed of 333 positive and 282 negative samples. The samples were obtained from 43 positive and 40 negative COVID-19 patients, respectively, and confirmed with RT-qPCR at two hospitals located in the Special Region of Yogyakarta, Indonesia. Four different machine learning algorithms (i.e., linear discriminant analysis, support vector machine, stacked multilayer perceptron, and deep neural network) were utilized to identify the top-performing pattern recognition methods and to obtain a high system detection accuracy (88–95%), sensitivity (86–94%), and specificity (88–95%) levels from the testing datasets. Our results suggest that GeNose C19 can be considered a highly potential breathalyzer for fast COVID-19 screening. [ABSTRACT FROM AUTHOR]

Bacillus amyloliquefaciens Q-426 with strong antifungal activity was isolated from the compost samples in Dalian of China. Four kinds of diketopiperazines were extracted from the strain including cyclo(Pro-Phe) (cPP), which had cyclo(L-Pro-L-Phe), cyclo(D-Phe-L-Pro), cyclo(D-Pro-D-Phe) and cyclo(L-Pro-D-Phe) isomers. Results showed that (1) cPP production reached the maximum at 12 h and then maintained the constant yield; (2) cPP maintained a stable production in a wide temperature range of 31–42°C; (3) cPP production were quite different for various carbon sources because of the different growth rate of the strain; (4) cPP maintained a higher level yield in neutral and weakly alkaline environment (pH 6–10) than acid (pH 3–5) environment. Moreover, cPP played a negative effect on the synthesis of antifungal substance when the bacteria maintained a good growth, and the previous studies found that cPP showed a positive response to biosensors which were used to detect signal molecules. Based on these studies, diketopiperazines were suspected as the signal molecule of B. amyloliquefaciens Q-426. [ABSTRACT FROM AUTHOR]