Disposable sensors in diagnostics, food and environmental monitoring

Disposable sensors are low‐cost and easy‐to‐use sensing devices intended for short‐term or rapid single‐point measurements. The growing demand for fast, accessible, and reliable information in a vastly connected world makes disposable sensors increasingly important. The areas of application for such devices are numerous, ranging from pharmaceutical, agricultural, environmental, forensic, and food sciences to wearables and clinical diagnostics, especially in resource‐limited settings. The capabilities of disposable sensors can extend beyond measuring traditional physical quantities (for example, temperature or pressure); they can provide critical chemical and biological information (chemo‐ and biosensors) that can be digitized and made available to users and centralized/decentralized facilities for data storage, remotely. These features could pave the way for new classes of low‐cost systems for health, food, and environmental monitoring that can democratize sensing across the globe. Here, a brief insight into the materials and basics of sensors (methods of transduction, molecular recognition, and amplification) is provided followed by a comprehensive and critical overview of the disposable sensors currently used for medical diagnostics, food, and environmental analysis. Finally, views on how the field of disposable sensing devices will continue its evolution are discussed, including the future trends, challenges, and opportunities

Validation of a portable device (iSperm ®) for the assessment of stallion sperm motility and concentration

The objective of this study was to evaluate the accuracy of a novel, portable device (iSperm (R) Equine for assessing concentration and motility of stallion semen). In the first experiment, semen concentration was determined by the iSperm (R) Equine (Aidmics Biotechnology), Androvision (R) (Minitube) and NucleoCounter (R) SP-100 (TM) (ChemoMetec). The total motility and progressive motility were determined by the iSperm (R) Equine and the Androvision (R) using the manufacturer's guidelines. Frozen/thawed semen samples (n = 33) at various dilutions were analysed for concentration and motility with the above-mentioned devices. There was a significant correlation between the concentrations measured with iSperm (R) and NucleoCounter (R) at all the measured dilutions. Moreover, <10% difference in concentrations was observed between the iSperm (R) and NucleoCounter (R) using the Bland-Altman test. There was also a significant correlation between iSperm (R) and Androvision (R) for total and progressive motility. In the second experiment, the parameters used in the Androvision (R) were modified to match those of the iSperm (R). Total motility and progressive motility of frozen/thawed semen samples (n = 10) were determined, and the similarity between the Androvision (R) and iSperm (R) was confirmed by correlation studies and Bland-Altman test. The results of these experiments demonstrate that the iSperm (R) offers a reliable and practical alternative for the semi-automated measurement of concentration and motility of stallion semen in the field. The iSperm (R) enables the practitioner to obtain objective and repeatable measurements on a variety of semen types (fresh, cooled and frozen) in the field at the time of insemination and thus acquire more insight into the quantity and quality of the provided insemination doses. This mare-side diagnostic tool may help practitioners in identifying presumed subfertility problems more rapidly and act accordingly

Properties of highly electronegative plasmas produced in a multipolar magnetic-confined device with a transversal magnetic filter

International audienceHighly electronegative plasmas were produced in Ar/SF 6 gas mixtures in a DC discharge with multipolar magnetic confinement and transversal magnetic filter. Langmuir probe and mass spectroscopy were used for plasma diagnostics. Plasma potential drift, the influence of small or large area biased electrodes on plasma parameters, the formation of the negative ion sheath, and etching rates by positive and negative ions have been investigated for different experimental conditions. Reducing the electron temperature below 1 eV the density ratio of negative ion to electron exceeded 100 even for very low amounts of SF 6 gas. The plasma potential drift could be controlled by proper wall conditioning. A large-electrode biased positively had no effect on plasma potential for density ratios of negative ion to electrons larger than 50. For similar electronegativities or higher a negative ion sheath could be formed by applying a positive bias of a few hundred volts