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.

Wearable devices provide an alternative pathway to clinical diagnostics by exploiting various physical, chemical and biological sensors to mine physiological (biophysical and/or biochemical) information in real time (preferably, continuously) and in a non-invasive or minimally invasive manner. These sensors can be worn in the form of glasses, jewellery, face masks, wristwatches, fitness bands, tattoo-like devices, bandages or other patches, and textiles. Wearables such as smartwatches have already proved their capability for the early detection and monitoring of the progression and treatment of various diseases, such as COVID-19 and Parkinson disease, through biophysical signals. Next-generation wearable sensors that enable the multimodal and/or multiplexed measurement of physical parameters and biochemical markers in real time and continuously could be a transformative technology for diagnostics, allowing for high-resolution and time-resolved historical recording of the health status of an individual. In this Review, we examine the building blocks of such wearable sensors, including the substrate materials, sensing mechanisms, power modules and decision-making units, by reflecting on the recent developments in the materials, engineering and data science of these components. Finally, we synthesize current trends in the field to provide predictions for the future trajectory of wearable sensors.

Noncoding small RNAs, such as microRNAs, are becoming the biomarkers of choice for multiple diseases in clinical diagnostics. A dysregulation of these microRNAs can be associated with many different diseases, such as cancer, dementia, and cardiovascular conditions. The key for effective treatment is an accurate initial diagnosis at an early stage, improving the patient's survival chances. In this work, the first clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a‐powered microfluidic, integrated electrochemical biosensor for the on‐site detection of microRNAs is introduced. Through this unique combination, the quantification of the potential tumor markers microRNA miR‐19b and miR‐20a is realized without any nucleic acid amplification. With a readout time of 9 min and an overall process time of less than 4 h, a limit of detection of 10 pm is achieved, using a measuring volume of less than 0.6 µL. Furthermore, the feasibility of the biosensor platform to detect miR‐19b in serum samples of children, suffering from brain cancer, is demonstrated. The validation of the obtained results with a standard quantitative real‐time polymerase chain reaction method shows the ability of the electrochemical CRISPR‐powered system to be a low‐cost, easily scalable, and target amplification‐free tool for nucleic acid based diagnostics.