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This paper presents a Chitosan-Graphene Oxide (CS-GO)-based array of ultra-thin biosensors with gold (Au)-based microgap ( $60~\mu \text{m}$ ) electrode. The cross-linked GO is shown to improve the stability of chitosan substrate in aqueous medium and compatibility with microfabrication steps. The sensor patch has been evaluated for label-free monitoring by immobilizing the CS-GO surface with human dermal fibroblast (HDF) cells. The cyclic voltammetry (CV) of HDF cell immobilized CS-GO surface show quasi-reversible nature with a characteristic cathodic peak at +300 mV and anodic peak at −300 mV. Both peaks are stable and repeatable up to 50-scan cycle without any potential shift. The device shows a steady-state peak enhancement (1.923-11.195nA) during the DHF cell growth period (0-96h). The redox peak enhancement correlates with the cell proliferation rates over time, indicating that it could be employed for investigation of the cyto-physiological state against any endo and exogenous stimulation. In addition, the developed sensor-patch was used to detect a wide range of glucose from $1~\mu \text{M}$ to 20mM in vitro with a sensitivity of $0.17~\mu \text{A}$ /mM. Considering these, the presented sensor-patch has a great potential for the detection of glucose level, cell-health proliferation rate at the wound site, and diabetic wound monitoring applications.

This work presents a screen-printed LC resonant tank-based strain sensor. The resonant tank consists of a planar inductor and an interdigitated capacitor connected in parallel. The inductor was screen printed on flexible polyamide substrate and the capacitor is printed on the piezoelectric Poly-L-lactide (PLLA) nanofibers obtained by electrospinning. The resonant frequency of the tank is tuned for ~13.56 MHz. The inductors and capacitors were characterized using an impedance analyzer to evaluate the frequency characteristic of both. As the interdigitated capacitor is realized on a piezoelectric substrate the permittivity and hence the capacitance varies with the application of dynamic pressure. For the dynamic pressure, less than 2 kPa the sensitivity S 1 is 8.55 kPa-1. The sensitivities in the range of 2-4 kPa-1 and 4-7 kPa-1 are calculated as S 2 = 31.27 kPa-1 and S 3 = 8.61 kPa-1 respectively. The fabricated flexible sensor shows the potential for wearable applications such as sub-bandage pressure monitoring while also exploiting the piezoelectric properties of PLLA to accelerate the wound healing through electrical stimulation.

This work presents a biodegradable flexible pressure sensor using a piezoelectric layer sandwiched between Mg electrodes. The active layer of the sensor is a piezoelectric composite of β-glycine amino acid and natural chitosan polymer, fabricated by self-assembly of glycine molecules inside polymer. As a result, a one-step solution casting method have been used to fabricate the biodegradable piezoelectric composite. The x-ray diffraction confirms the structure and crystalline nature of β-glycine crystals inside the chitosan matrix and hence its piezoelectric nature. The sensitivity of the fabricated pressure was about ~ 1.42 mV in the range of 5-25 kPa. The in-vitro degradability of the device has been confirmed in cell culture medium. The fabricated biodegradable sensor offers potential for point-of-care and implantable healthcare applications.

This work presents biocompatible flexible piezoelectric composite fabricated by self-assembly of amino acid glycine molecules inside natural chitosan polymer. Piezoelectric composite film consists of glycine spherulite structure embedded in chitosan matrix. The x-ray diffraction confirms the crystallization of stable $\beta$-glycine inside the composite and hence its piezoelectric nature. As a result, a simple solvent-casting technique have been used to fabricate the biodegradable composite of $\beta$-glycine/chitosan with significant piezoelectric response. We show that the piezoelectric sensor can precisely measure pressure in the range of 0-40 kPa with sensitivity of $\sim 4.7$ mV kPa$^{-1}$. The devices based on bio-based functional material such as glycine offer huge potential for disposable wearable health applications such as monitoring the pressure in a compression bandage.

The results are based on the first principal modeling and calculations for HAP nanostructures as native as well surface modified, charged and having various defects (H and OH vacancies, H inter-nodes). HAP structures were studied using Local Density Approximation (LDA) method with calculations of Density of States (DOS) allow us analyzes the experimental work function data. Molecular modeling by HyperChem is confirmed by photo-electron monochromatic measurements up 6.5 eV and photo-luminescence data from synchrotron DESY experimental data up 30 eV values. Brief analysis of the influence of heating, microwave radiation, hydrogenation, x-rays and synchrotron radiation on Hydroxyapatite (HAP) surface is presented in this work. New data of the structure of hydroxyapatite are obtained.

This work presents an advanced soft robotic finger with integrated strain sensor based on carbon nanotubes (CNTs). The interdigitated strain sensor is obtained by dielectrophoretic assembled CNT network. The sensor is connected to stretchable interconnects to ensure robust electrical connection during movements of the soft finger. The sensor is highly sensitive with up to 1300% change in the resistance for 11% strain. Finally, the CNT strain sensor is integrated with a soft robotic finger to monitor the bending for real time kinesthetic tactile feedback.