In this study, we developed a novel magnetic lateral flow assay based on iron oxide decorated with platinum probes (Fe3O4@Pt) for dual-mode detection of gastrin-17 (G-17), which is one of...

Against the backdrop of hidden symptoms of diseases and limited medical resources of their investigation, in vitro diagnosis has become a popular mode of real-time healthcare monitoring. Electrochemical biosensors have considerable potential for use in wearable products since they can consistently monitor the physiological information of the patient. This review classifies and briefly compares commonly available electrochemical biosensors and the techniques of detection used. Following this, the authors focus on recent studies and applications of various types of sensors based on a variety of methods to detect common compounds and cancer biomarkers in humans. The primary gaps in research are discussed and strategies for improvement are proposed along the dimensions of hardware and software. The work here provides new guidelines for advanced research on and a wider scope of applications of electrochemical biosensors to in vitro diagnosis. Graphical abstract

In this research, we design and implement a small, convenient, and noninvasive paper-based microfluidic sweat sensor that can simultaneously detect multiple key biomarkers in human sweat. The origami structure of the chip includes colorimetric and electrochemical sensing regions. Different colorimetric sensing regions are modified with specific chromogenic reagents to selectively identify glucose, lactate, uric acid, and magnesium ions in sweat, as well as the pH value. The regions of electrochemical sensing detect cortisol in sweat by molecular imprinting. The entire chip is composed of hydrophilically and hydrophobically treated filter paper, and 3D microfluidic channels are constructed by using folding paper. The thread-based channels formed after the hydrophilic and hydrophobic modifications are used to control the rate of sweat flow, which in turn can be used to control the sequence of reactions in the differently developing colored regions to ensure that signals of the best color can be captured simultaneously by the colorimetric sensing regions. Finally, the results of on-body experiments verify the reliability of the proposed sweat sensor and its potential for the noninvasive identification of a variety of sweat biomarkers.

Nanomaterials, especially superparamagnetic nanomaterials, have recently played essential roles in point-of-care testing due to their intrinsic magnetic, electrochemical, and optical properties. The inherent superparamagnetism of magnetic nanoparticles makes them highly sensitive for quantitative detection. Among the various magnetic detection technologies, frequency mixing technology (FMT) technology is an emerging detection technique in the nanomedical field. FMT sensors have high potential for development in the field of biomedical quantitative detection due to their simple structure, and they are not limited to the materials used. In particular, they can be applied for large-scale disease screening, early tumor marker detection, and low-dose drug detection. This review summarizes the principles of FMT and recent advances in the fields of immunoadsorption, lateral flow assay detection, magnetic imaging, and magnetic nanoparticles recognition. The advantages and limitations of FMT sensors for robust, ultrasensitive biosensing are highlighted. Finally, the future requirements and challenges in the development of this technology are described. This review provides further insights for researchers to inspire the future development of FMT by integration into biosensing and devices with a broad field of applications in analytical sensing and clinical usage.frequency mixing technology (FMT), lateral flow assay (LFA), magnetic imaging, magnetic nanoparticles (MNPs), point-of-care testing (POCT) | INTRODUCTIONRapid medical diagnosis is difficult using current laboratory testing techniques and their application is hindered by factors such as equipment requirements, operator capabilities, and the testing time.In particular, there is an increasing demand for rapid, convenient, and high precision medical diagnosis techniques for detecting coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome (SARS), and other highly contagious infectious diseases (Alfadly et al., 2020;Chu et al., 2021;X. Dong et al., 2021). Point-of-care testing (POCT) can be used for in vitro clinical testing and diagnosis (Wei et al., 2021;Yan et al., 2019). POCT usually refers to detection techniques that do not require a professional operator to perform tests at the bedside next to the patient (Nichols, 2003;Wang et al., 2021;Xia et al., 2016). POCT is characterized by rapid analysis at the sampling site, and thus complicated laboratory processing procedures are not required (Sharma et al., 2021). POCT methods might not have the same level of sensitivity and accuracy compared with laboratory-level medical diagnosis techniques. However, with the advantages of its simple implementation and lack of requirement for professional operational support, this technology receives widespread attention in countries and regions, especially those with a low level of

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