Lactate is one of the potential biomarkers for assessing the human condition in clinical medicine or sports application. Lactate measurement could help in alerting various emergency conditions, such as bleeding, hypoxia, respiratory failure, and sepsis. Lactate monitoring could also benefit athletes in monitoring their muscle activity to prevent injury due to excessive muscle use or fatigue. In light of this, biosensor technology has been widely explored, especially on the use of electrochemical sensors to analyze the content of biological samples through direct biological activities conversion to electronic signals. This has become imperative for the detection of lactate which offers easy, quick, and reliable measurement. Despite enzymatic sensors being the focus of many studies, the non-enzymatic sensor has started to gain attention in recent years to overcome the stability issue of enzymes. This review presents an overview of the concepts, applications, and recent advancements of different electrochemical lactate sensors. A comparison of recent studies for both enzymatic and non-enzymatic lactate sensors based on electrode modification, enzymes, enzymes immobilizer, and several performance factors, including sensitivity, linearity, detection limit, and storage stability, all of which have been performed. Towards the end, this review also highlights some recommendations for future development of lactate sensors.

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Acoustics have a wide range of uses, from noise-cancelling to ultrasonic imaging. There has been a surge in interest in developing acoustic-based approaches for biological and biomedical applications in the last decade. This review focused on the application of surface acoustic waves (SAW) based on interdigital transducers (IDT) for live-cell investigations, such as cell manipulation, cell separation, cell seeding, cell migration, cell characteristics, and cell behaviours. The approach is also known as acoustofluidic, because the SAW device is coupled with a microfluidic system that contains live cells. This article provides an overview of several forms of IDT of SAW devices on recently used cells. Conclusively, a brief viewpoint and overview of the future application of SAW techniques in live-cell investigations were presented.

The ability to accurately detect and analyze rare cells in a cell population is critical not only for the study of disease progression but also for next flow cytometry systems in clinical application. Here, we report the development of a prototype device, the ‘Rare cell sorter’, for isolating and recovering single rare cells from whole blood samples. On this device, we utilized an open-channel microfluidic chip for rare cell isolation. And the advantage of open-channel allows us to recover the isolated rare cell directly from the chip. We set the circulating tumor cell (CTC) as a target cell.For the clinical experiment, CTCs were isolated from blood samples collected from patients with metastatic breast cancer and healthy volunteers. There was a significant difference in the number of CTCs between the patients with metastatic breast cancer and healthy volunteers. To evaluate the damage to cells during isolation and recovery, we performed an RNA integrity assay using RNA extracted from CTCs recovered from the chip and found that our process for single CTC isolation and recovery is mild enough for gene analysis of CTCs.

Sweat analysis offers non-invasive real-time on-body measurement for wearable sensors. However, there are still gaps in current developed sweat-sensing devices (SSDs) regarding the concerns of mixing fresh and old sweat and real-time measurement, which are the requirements to ensure accurate the measurement of wearable devices. This review paper discusses these limitations by aiding model designs, features, performance, and the device operation for exploring the SSDs used in different sweat collection tools, focusing on continuous and non-continuous flow sweat analysis. In addition, the paper also comprehensively presents various sweat biomarkers that have been explored by earlier works in order to broaden the use of non-invasive sweat samples in healthcare and related applications. This work also discusses the target analyte’s response mechanism for different sweat compositions, categories of sweat collection devices, and recent advances in SSDs regarding optimal design, functionality, and performance.