Abha Umesh Sardesai

A novel electrochemical sensor is reported for the detection of isoprene levels in breath using a ZIF-based electrochemical nose. This sensor incorporates a hybrid detection system using gold nanoparticles encapsulated inside the ZIF-8 moiety. Breath-based analysis is widely being used for monitoring the metabolic state of the body. It is associated with the change in the concentration of volatile organic compounds and inorganic gases released endogenously and can be tracked using breath as the sample. One such volatile organic compound, isoprene, has been correlated to the presence of influenza virus or respiratory inflammation. Analytical techniques such as powder X-ray diffraction, scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and tunneling electron microscopy were used to understand the structural features of the composite. The electrochemical nose system uses chronoamperometry as the transduction mechanism to monitor the diffusion kinetics of the target analyte across the electrode–electrolyte interface. The presented work demonstrates isoprene sensing with high sensitivity and specificity and a detection limit of 10 parts per billion in air. We successfully demonstrate the functionality of the ZIF-based electrochemical nose for point-of-care screening of isoprene levels by developing a prototype device using a commercially available development board. We foresee that the developed sensing platform can help in early screening for the presence of influenza virus and help control the infection rate. Graphical abstract

Sepsis is a silent killer, caused by a syndromic reaction of the body's immune system to an infection that is typically the ultimate pathway to mortality due to numerous infectious diseases, including COVID‐19 across the world. In the United States alone, sepsis claims 220,000 lives, with a dangerously high fatality rate between 25% and 50%. Early detection and treatment can avert 80% of sepsis mortality which is currently unavailable in most healthcare institutions. The novelty in this work is the ability to simultaneously detect eight (IL‐6, IL‐8, IL‐10, IP‐10, TRAIL, d‐dimer, CRP, and G‐CSF) heterogeneous immune response biomarkers directly in whole blood without the need for dilution or sample processing. The DETecT sepsis (Direct Electrochemical Technique Targeting Sepsis) 2.0 sensor device leverages electrochemical impedance spectroscopy as a technique to detect subtle binding interactions at the metal/semi‐conductor sensor interface and reports results within 5 min using only two drops (~100 μl) of blood. The device positively (r >0.87) correlated with lab reference standard LUMINEX for clinical translation using 40 patient samples. The developed device showed diagnostic accuracy greater than 80% (AUC >0.8) establishing excellent specific and sensitive response. Portable handheld user‐friendly feature coupled with precise quantification of immune biomarkers makes the device amenable in a versatile setting providing insights on patient's immune response. This work highlights an innovative solution of enhancing sepsis care and management in the absence of a decision support device in the continuum of sepsis care.

A novel synthesized [BMIM]BF ₄ @ZIF-8 nanocomposite for electrochemical sensing of isopentane as a biomarker for lung cancer diagnosis.

C-reactive protein (CRP) is considered to be an important biomarker associated with many diseases. During any physiological inflammation, the level of CRP reaches its peak at 48 h, whereas its half-life is around 19 h. Hence, the detection of low-level CRP is an important task for the prognostic management of diseases like cancer, stress, metabolic disorders, cardiovascular diseases, and so on. There are various techniques available in the market to detect low-level CRP like ELISA, Western blot, etc. An electrochemical biosensor is one of the important miniaturized platforms which provides sensitivity along with ease of operation. The most important element of an electrochemical biosensor platform is the electrode which, upon functionalization with a probe, captures the selective antibody–antigen interaction and produces a digital signal in the form of potential/current. Optimization of the electrode design can increase the sensitivity of the sensor by 5–10-fold. Herein, we come up with a new sensor design called the spiral electrochemical notification coupled electrode (SENCE) where the working electrode (WE) is concentric in nature, which shows better response than the market-available standard screen-printed electrode. The sensor is thoroughly characterized using a standard Ferro/Ferri couple. The sensing performance of the fabricated platform is also characterized by the detection of standard H₂O₂ using a diffusion-driven technique, and a low detection limit of 15 µM was achieved. Furthermore, we utilized the platform to detect a low level (100 ng/mL) of CRP in synthetic sweat. The manuscript provides emphasis on the design of a sensor that can offer good sensitivity in electrochemical biosensing applications.