Sustainable and eco-friendly biosensing technologies are emerging as a potential approach for healthcare improvement while simultaneously reducing environmental impact. In this study, a novel uric acid biosensor has been developed using green-synthesized molybdenum oxide (MoO3) thin films, which demonstrates a creative way to repurpose waste for advanced technological applications. The structural and morphological studies confirmed the uniformity and high quality of the MoO3 thin films, which played a key role in enhancing sensor performance. The fabricated biosensor demonstrated high sensitivity [244.76 µA/(mM cm2)], a fast response time of 5 s, and excellent selectivity against common interferents which are typically found in blood plasma. Additionally, the low Michaelis–Menten constant (Kₘ = 0.07311 mM) indicates that the enzyme maintained a strong affinity for uric acid, ensuring reliable detection even at low concentrations. In addition to its strong analytical performance, this work highlights the potential of green synthesis in the development of biosensors. By integrating eco-conscious material synthesis with high-performance sensing capabilities, this work lays the foundation for more sustainable, cost-effective, and efficient biosensors for healthcare applications. This approach not only enhances biosensing technology but also aligns with global efforts to minimize waste and promote greener alternatives in scientific innovation.

Alzheimer's disease (AD) is a degenerative neurological disorder that poses a significant global health challenge, impacting millions of individuals worldwide. While at the present moment, no treatment exists for AD, early diagnosis and prevention are the only ways to tackle the disease. Amyloid beta 42 (A beta 42) has emerged as one of the potential biomarkers for early diagnosis of AD and there is a need to develop biosensors that can accurately measure A beta 42 levels. This work introduces an immunosensor based on an RF-sputtered NiO thin film, developed for A beta 42 quantification. The sensor demonstrates good performance, delivering a stable response across a wide A beta 42 concentration range, from 100 fg ml-1 to 10 ng ml-1, with an impressive limit of detection (LOD) of 1.23 x 10-5 pg ml-1. The sensor also exhibited excellent selectivity and stability towards A beta 42 with a shelf life of the bioelectrode tested over 8 weeks. The prepared A beta Ab/NiO/ITO bioelectrode has potential for the development of an immunosensor for point-of-care application for AD detection.

Thin films of Lead Zirconium Titanate (PZT) were deposited using chemical solution deposition technique. To investigate the effect of substrate on the ferroelectric properties of lead zirconium titanate films, Nickel and platinized silicon substrates were chosen. The structural and ferroelectric properties have been investigated for the PZT films grown on both nickel and platinized silicon. The 650 degrees C growth temperature was found to be the optimized temperature for the formation of pure PZT phase having polycrystalline structure. The obtained results clearly suggest that the ferroelectric property for the PZT thin film depends largely on the substrate used for the film growth. The PZT film grown of nickel substrate is found to have better ferroelectric properties in comparison to those deposited over platinized silicon.

The current work investigates the influence of the Au catalyst layer on the development of ZnO nanostructures using the vapour liquid solid (VLS) modification of the vapour phase transport technique and their suitability as an efficient platform for detection of free cholesterol. ZnO nanostructures were prepared with and without the catalyst and subsequently, were characterized for structural, morphological, electrical and electrochemical properties. These ZnO nanostructures were deposited on platinum coated silicon (Pt/Si) to fabricate bioelectrodes forming ZnO/Pt/Si and ZnO/Au/Pt/Si configuration. The presence of catalyst was seen to considerably enhance the crystallinity, mobility, shape and morphology of the fabricated nanostructures. Most importantly, it was seen to enhance the electron transfer characteristics leading to a better electrochemical response. It was observed that the bioelectrode with Au as a catalyst layer leads to enhancement in sensitivity of ZnO nanostructures towards the detection of free cholesterol. The enhanced biosensing performance with sensitivity of 280 µAmM-1cm-1, linearity across a wide range from 0.12–12.93 mM of cholesterol and shelf life of 10 weeks is attributed to the presence of Au catalyst. Additionally, the study demonstrated that the Au-catalyzed ZnO nanostructures exhibit excellent reproducibility and stability, essential for practical biosensor applications.

A novel biosensor for uric acid detection was developed using green-synthesized molybdenum oxide (MoO3) thin films. The MoO3 thin films were synthesized using Citrus limetta pith extract, which is typically considered waste, showcasing an innovative approach to repurposing waste materials. The fabrication process involved the deposition of a MoO3 thin film onto an indium-doped tin oxide (ITO) glass substrate via chemical solution deposition, followed by the immobilization of the uricase enzyme on the fabricated film. The fabricated sensors showed a high sensitivity of 212 µA/(mM·cm2) for uric acid, covering a wide range of concentrations within the physiological range. It also had a quick response time of 5 s and excellent selectivity against common interferents in plasma. The low Michaelis–Menten constant (Km) of 0.0537 mM indicates that the immobilized uricase enzyme has an enhanced affinity for its analyte, uric acid. This biosensor demonstrates high sensitivity and specificity for uric acid, emphasising the effectiveness of green synthesis techniques in advancing biosensor technology. Additionally, it highlights the potential for sustainable innovation by utilizing waste materials.

The present work investigates the structural, electrical, and ferroelectric properties of KxNa1-xNbO3 thin films at morphotropic phase boundary [KNN-50 (x = 0.50)]. RF magnetron sputtering was used to deposit the KNN thin films under optimized deposition parameters X-ray diffraction (XRD) technique and UV-Visible spectroscopy were used to analyze the structural and optical properties of the grown thin films respectively. The electrical studies of KNN thin film were carried out in the metal-insulator-metal (MIM) configuration. Well-saturated polarization versus electric field hysteresis loop with high value of remnant polarization was obtained on the KNN film, confirming its ferroelectric nature. The outcomes are encouraging to use KxNa1-xNbO3 thin films in ferroelectric and nonlinear optical applications.

In this study, sol gel technique is used to fabricate manganese (Mn) doped ZnO thin films and further utilize them as a platform for uric acid biosensors. The objective was to introduce manganese into the ZnO matrix to enhance its redox properties, capitalizing on the multivalent nature of manganese. The Mn-doped thin films of concentrations varying from 3 %,5 %,7 % and 10 % were prepared and further characterized using UV-vis spectroscopy, X-ray diffraction (XRD) spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and cyclic voltammetry (CV) measurements. The ZnO thin films with 7 % doping of Mn exhibited improved redox behaviour, as evident by the distinct redox peaks. In order to immobilise the uricase enzyme, the 7 % Mn doped composition was used, creating a highly sensitive and focused uric acid detection platform. The fabricated biosensor exhibits excellent performance in terms of sensitivity (40 mu AmM(-1)cm(-2)), selectivity with <5 % deviation found in presence of other known markers present in human sera, and shelf life >12 weeks, enabling precise and sensitive uric acid detection. This study brings to light an alternate approach in developing point of care biosensors using transition metal doped ZnO thin films.

In the present study, a fabrication technique using self-aligned shadow masking was employed to create thermoelectric single-leg array of Antimony telluride thin film via thermal evaporation technique. The structural properties of the fabricated array were examined using X-ray diffraction, while scanning electron microscopy with EDAX (Energy-dispersive X-ray spectroscopy) was employed to investigate the surface morphology and compositional analysis of the grown thin films. The thermoelectric performance of the array was evaluated using an indigenously developed thermoelectric measurement setup. The results revealed a Seebeck coefficient of 583 mu V/K and 568 mu V/K respectively for both heating and cooling within the temperature range of 300-498 K.

The development of a piezoelectric generator (PEG) that exhibits improved durability, stability, and enhanced output performance continues to be a crucial objective for self-powered and wearable electronic devices. In this study, a PEG was constructed using nanocomposite films composed of sol-gel derived Barium Strontium Titanate (BST) filler embedded within a Polyvinylidene fluoride (PVDF) matrix. This flexible polymer matrix structure is selected for its exceptional performance, flexibility, and cost-efficiency, making it ideal for advanced piezoelectric applications. Homogeneous nanocomposite films of PVDF-BST with different proportions of BST were fabricated using the solution casting method. Integrating BST filler into the PVDF matrix significantly enhances the nucleation of the electroactive beta-phase, thereby improving the dielectric and ferroelectric properties, which vary according to the volume fraction of BST used. Specifically, the PVDF-BST composite containing 10 % BST (PB10) exhibited the highest electroactive beta-phase content at 41.8 %, and demonstrated an energy storage density of 0.8 J/cm3 3 with an efficiency of 73.9%. The dielectric constant at room temperature is seen to rise from 23 in pure PVDF to 132 in the PB20 composition at 1 kHz. The open-circuit voltage (Voc) oc ) of the PEG was recorded by exerting a periodic force on its surface. Notably, the PB10 variant achieved the highest peak-to-peak open- circuit voltage, reaching 28 V. Additionally, PB10 produced an open-circuit voltage of 22 V in response to finger tapping, highlighting its suitability for applications in touch and pressure sensing.

We present fabrication of silver nanostructures on glass substrates using highly energetic and high fluence material ions generated by one shot of hot, dense and extremely non-equilibrium plasma such as found in modified dense plasma focus (DPF) device. The substrates were first placed at 4.0 cm and 6.0 cm from the top of anode. Nanodots and nanocapsules are observed in the scanning electron microscopy (SEM) images of silver ions deposited with DPF shot on glass. The interparticle distance is found to decrease whereas mean size of nanodots is found to increase slightly when the distance of glass substrate is increased from 4.0 cm to 6.0 cm. The X-ray diffraction (XRD) pattern of the fabricated nanostructures has peaks at 2θ equals 37.90o, 44.24o and 64.20o which correspond to (111), (200) and (220) planes of silver having face-centered cubic structure. The nanostructures obtained on glass placed at 4.0 cm show surface plasmon resonance (SPR) peak at 420 nm whereas nanostructures obtained on glass placed at 6.0 cm has a SPR peak at 428 nm. Redshift of the SPR peak is attributed to increased interaction as a result of decrease in interparticle distance of the nanostructures as well as increase in mean size of nanodots.

We report fabrication of gold nanostructures on glass and indium tin oxide (ITO)-coated glass substrates using high fluence and highly energetic gold ions generated by hot, dense, and strongly non-equilibrium plasma. Nanodots and nanorods are observed in scanning electron microscopy (SEM) of nanostructures grown on glass substrate with single and double shots of gold ions which is in conformity with the transmission electron microscopy image. SEM images for single and double shots of gold ions on ITO-coated glass substrate show only nanodots. The mean diameter of nanodots obtained on both glass and ITO-coated glass is found to increase with increase in the number of gold ions shot from one to two. The gold nanostructures exhibit red shift in surface plasmon resonance with increased interaction which is in agreement with other reported work.

Plasma route to nanofabrication has drawn much attention recently. The dense plasma focus (DPF) device is used for depositing aluminium nanoparticles on n-type Si (111) wafer. The plasma chamber is filled with argon gas and evacuated at a pressure of 80 Pa. The substrate is placed at distances 4.0 cm, 5.0 cm and 6.0 cm from the top of the central anode. The aluminium is deposited on Si wafer at room temperature with two focused DPF shots. The deposits on the substrate are examined for their morphological properties using atomic force microscopy (AFM). The AFM images have shown the formation of aluminium nanoparticles. From the AFM images, it is found that the size of aluminium nanoparticles increases with increase in distance between the top of anode and the substrate for same number of DPF shots.