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Cancer is a major global health burden and poor survival rates can be attributed to lack of early diagnosis and limited access to timely and standard treatments. Significant progress has been made in recent years to establish reliable, cost-effective, and powerful cancer diagnostics. This review presents the recent advances (mostly after 2018) in cancer diagnostic technologies with a prime focus on the various types of biomarkers investigated, such as nucleic acids, proteins, enzymes, and even entire cancer cells, typically known as circulating tumor cells (CTCs). It elucidates several seminal works that utilize a multidisciplinary approach to cancer diagnostics as an alternative to traditional screening methods. Different detection techniques used for each biomarker type have been comprehensively reviewed and our goal is to provide the reader with a critical overview of the current sense and sensibility in the field of cancer biosensing. Furthermore, we discuss emerging trends in cancer biomarker detection using novel multiplexed and integrated platforms for accurate and easy readout, while also shedding light on their technical limitations and existing challenges in achieving high sensitivity and selectivity. We hope that this work will promote collaborative research among different disciplines with an ultimate goal of achieving personalized and user-friendly point-of-care technologies that enable early cancer diagnosis and significantly reduced cancer mortality.

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Breath monitoring and pulmonary function analysis have been the prime focus of wearable smart sensors owing to the COVID-19 outbreak. Currently used lung function meters in hospitals are prone to spread the virus and can result in the transmission of the disease. Herein, we have reported the first-ever wearable patch-type strain sensor for enabling real-time lung function measurements (such as forced volume capacity (FVC) and forced expiratory volume (FEV) along with breath monitoring), which can avoid the spread of the virus. The noninvasive and highly sensitive strain sensor utilizes the synergistic effect of two-dimensional (2D) silver flakes (AgFs) and onedimensional (1D) silver nanowires (AgNWs), where AgFs create multiple electron transmission paths and AgNWs generate percolation networks in the nanocomposite. The nanocomposite-based strain sensor possesses a high optimized conductivity of 7721 Sm −1 (and a maximum conductivity of 83,836 Sm −1 ), excellent stretchability (>1000%), and ultrasensitivity (GFs of 35 and 87 when stretched 0−20 and 20−50%, respectively), thus enabling reliable detection of small strains produced by the body during breathing and other motions. The sensor patching site was optimized to accurately discriminate between normal breathing, quick breathing, and deep breathing and analyze numerous pulmonary functions, including the respiratory rate, peak flow, FVC, and FEV. Finally, the observed measurements for different pulmonary functions were compared with a commercial peak flow meter and a spirometer, and a high correlation was observed, which highlights the practical feasibility of continuous respiratory monitoring and pulmonary function analysis.

Owing to their excellent sensitivity, stretchability, flexibility and conductivity, polymeric nanocomposites with conductive fillers have shown promise for a wide range of applications in bioelectronics and wearable devices. Herein, we...

Herein, we report the development of a novel enzymeless electrochemical biosensor for highly specific detection of creatinine utilizing zwitterion-functionalized cuprous oxide nanoparticles (Cu2O NPs). We utilized a simple yet effective alternative to traditionally used cover layers based on the surface engineering of Cu2O NPs with N-hexadecyl-N,N dimethyl-3-ammonio-1-propanesulfonate zwitterion. This surface modification generates a pseudo-proton-exchange membrane which electrostatically hinders interfering agents from reaching the electrode surface, thus resulting in highly specific creatinine detection without loss in sensitivity. To fabricate the enzymeless biosensor, single-crystalline Cu2O NPs were synthesized via a sulfonate ion-directed seed aging protocol and were simply drop-cast onto screen-printed carbon electrodes. The shape directional effect of sulfonate ions to induce truncation in the final morphologies of the synthesized Cu2O NPs is also reported for the first time. The creatinine biosensor demonstrated fast response time (<50 s), good reproducibility (RSD = 2.8%, n = 10), and high specificity against interferents like ascorbic acid, acetic acid, glucose, urea, and uric acid. A linear response to creatinine concentration from 10 to 200 μM (R 2 = 0.9876 and LOD = 5.0 μM) was observed, which covers the entire range of physiological creatinine in human serum. Moreover, robust storage stability with a negligible decrease in signal strength over an extended storage period of 6 months was achieved, thus highlighting the practical feasibility for point-of-care testing of creatinine.

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In this study, polyethylene glycol (PEG) and polyurethane (PU)-based shape-stabilized copolymer nanocomposites were synthesized and utilized for developing low-cost and flexible temperature sensors. PU was utilized as a flexible structural material for loading a thermosensitive phase change PEG polymer by means of physical mixing and chemical crosslinking. Furthermore, the introduction of multi-walled carbon nanotubes (MWCNT) as a conductive filler in the PEG-PU copolymer resulted in a nanocomposite with thermoresistive properties. MWCNT loading concentrations from 2 wt.% to 10 wt.% were investigated, to attain the optimum conductivity of the nanocomposite. Additionally, the effect of MWCNT loading concentration on the thermosensitive behavior of the nanocomposite was analyzed in the temperature range 25 °C to 50 °C. The thermosensitive properties of the physically mixed and crosslinked polymeric nanocomposites were compared by spin coating the respective nanocomposites on screen printed interdigitated (IDT) electrodes, to fabricate the temperature sensor. The chemically crosslinked MWCNT-PEG-PU polymeric nanocomposite showed an improved thermosensitive behavior in the range 25 °C to 50 °C, compared to the physically mixed nanocomposite. The detailed structural, morphological, thermal, and phase transition properties of the nanocomposites were investigated using XRD, FTIR, and DSC analysis. XRD and FTIR were used to analyze the crystallinity and PEG-PU bonding of the copolymer nanocomposite, respectively; while the dual phase (solid–liquid) transition of PEG was analyzed using DSC. The proposed nanocomposite-based flexible temperature sensor demonstrated excellent sensitivity, reliability and shows promise for a wide range of bio-robotic and healthcare applications.