A highly selective and stable cationic polyelectrolyte encapsulated black phosphorene based impedimetric immunosensor for Interleukin-6 biomarker detection.

Due to the insufficiency of binding sites for the immobilized recognition biomolecules on the immunosensing platform, cancer detection becomes challenging. Whereas, the degradation of black phosphorene (BP) in the presence of the environmental factors becomes a concerning issue for use in electrochemical sensing. In this study, BP is successfully encapsulated by polyallylamine (PAMI) to increase its stability as well as to enhance its electrochemical performance. The successful encapsulation of BP is ensured through X-ray Photoelectron spectroscopy and Raman spectroscopy, whereas the stability of black phosphorus is ensured by Zeta potential measurements and cyclic voltammetry tests. The developed BP-PAMI composite showed high stability in the ambient environment and exhibited improved electrochemical performances. The impedimetric immunosensor was developed on a BP-PAMI modified laser burned graphene (LBG) to detect interleukin-6 biomarkers using electrochemical impedance spectroscopy (EIS). Under the optimized parameters, the fabricated immunosensor demonstrated a wide linear range of 0.003-75 ng/mL, limit of detection (LOD) of 1 pg/mL. Based on the experimental analysis, the developed sensing strategy can be employed as an easy, disposable, cost-effective and highly selective point-of-care cancer detection. In addition, the developed technique can be applied broadly for detecting other biomarkers after treating with suitable biomolecules.

A wearable battery-free wireless and skin-interfaced microfluidics integrated electrochemical sensing patch for on-site biomarkers monitoring in human perspiration.

In this study, an ultra-high sensitive, flexible, wireless, battery-free, and fully integrated (no external analysis equipment) electrochemical sensing patch system, including a microfluidic-sweat collecting unit, was newly developed for the on-site monitoring of the [K+] concentration in human sweat. Multiwalled carbon nanotube (MWCNT) and MXene-Ti3C2TX based hybrid multi-dimensional networks were applied to obtain a high surface activation area and faster charge transfer rate, strongly adsorbing the valinomycin membrane to protect the ionophore for effective transshipment and immobilization of the [K+]. Furthermore, the controllable porosity of carbon-based materials can accelerate the kinetic process of ion diffusion. This hybrid nanonetwork structure effectively enhanced electrochemical stability and sensitivity, addressing the noise and signal drifting problems experienced with low concentration detection. The fabricated sensor exhibited a high ion concentration sensitivity of 63 mV/dec with excellent selectivity, amplified to 173 mV/dec with the integrated amplification system. The Near Field Communication (NFC) is used to transmit measurements to a smartphone wirelessly. A microfluidic channel was integrated with the electrochemical sensor patch to efficiently collect sweat on the human skin surface and mitigate the sensor surface contamination problem. Furthermore, the developed sensing patch can also be applied to other biomarkers on-site detection after modifying the working electrode with the corresponding selective membranes.

Smart bandage with integrated multifunctional sensors based on MXene-functionalized porous graphene scaffold for chronic wound care management.

Three-dimensional (3D) porous laser-guided graphene (LGG) electrodes on elastomeric substrates are of great significance for developing flexible functional electronics. However, the high sheet resistance and poor mechanical properties of LGG sheets obstruct their full exploitation as electrode materials. Herein, we applied 2D MXene nanosheets to functionalize 3D LGG sheets via a C-O-Ti covalent crosslink to obtain an LGG-MXene hybrid scaffold exhibited high conductivity and improved electrochemistry with fast heterogeneous electron transfer (HET) rate due to the synergistic effect between LGG and MXene. Then we transferred the obtained hybrid scaffold onto PDMS to engineer a smart, flexible, and stretchable multifunctional sensors-integrated wound bandage capable of assessing uric acid (UA), pH, and temperature at the wound site. The integrated UA sensor exhibited a rapid response toward UA in an extended wide range of 50-1200 µM with a high sensitivity of 422.5 µA mM-1 cm-2 and an ultralow detection limit of 50 µM. Additionally, the pH sensor demonstrated a linear Nernstian response (R2 = 0.998) with a high sensitivity of -57.03 mV pH-1 in the wound relevant pH range of 4-9. The temperature sensor exhibited a fast and stable linear resistive response to the temperature variations in the physiological range of 25-50 °C with an excellent sensitivity and correlation coefficient of 0.09% °C-1 and 0.999, respectively. We anticipate that this stretchable and flexible smart bandage could revolutionize wound care management and have profound impacts on the therapeutic outcomes.