Agarwal, Ajay

In this paper, the hazardous effects of various volatile organic compounds (VOCs) on human health and its detection methods have been discussed. This paper also presents the comprehensive study on various VOC sensing mechanisms, their advantages, limitations and key design challenges. It is also reported that acoustic wave sensors are more suitable for VOC detection because of its various advantages as compared to other techniques such as, extended lifetime, miniaturization, high sensitivity, less/zero secondary pollution, low power consumption, lower detection limit and low-cost. The main focus of this paper is on bulk acoustic wave (BAW) devices for VOC detection. The development of film bulk acoustic wave resonators (FBARs) in various aspects such as, structural classification, operating modes, selection criteria of materials (electrode, piezoelectric and sensing layer) and their deposition methods, fabrication process flow and applications have been discussed in this detailed review. Various performance enhancement methods for efficient VOC detection using FBARs have been described in detail to design, model, analyze and optimize a FBAR sensors for the detection of various hazardous VOCs with enriched sensitivity and selectivity.

The field of biomedical materials has witnessed significant advancements in recent years, leading to the development of novel smart materials capable of interacting intelligently with the biological environment. This book chapter comprehensively explores the synthesis, applications, and safety considerations of nanomaterials in the context of cancer treatment. The chapter begins with an introduction to nanotechnology and its significance in biomedical research and cancer therapeutics. Next, the chapter explores the synthesis of nanomaterials, covering both top-down and bottom-up approaches. The top-down approach involves the fabrication of nanoparticles (NPs) from more extensive materials through techniques such as milling and lithography. In contrast, the bottom-up approach focuses on assembling nanoscale building blocks to form NPs using chemical synthesis and self-assembly methods. It highlights the importance of material selection, processing techniques, and integrating functional components, such as NPs, nanofibers, and hydrogels, to enhance their performance and efficacy. Furthermore, the chapter discusses bioconjugation strategies for biomedical applications, emphasizing their role in improving NP functionality and targeting abilities for cancer treatment. Various techniques, including surface modification and functionalization, are discussed to enhance the biocompatibility and specificity of NPs in targeting cancer cells. The chapter further delves into specific types of NPs used in cancer treatment. Plasmonic NPs, known for their unique optical properties, are examined for their applications in cancer therapy. Their use in photothermal therapy (PTT) is discussed, highlighting their potential in targeted cancer cell destruction. Inorganic-based NPs, specifically those employed in drug delivery systems and PTT, are investigated for their effectiveness in cancer treatment. Their controlled drug release mechanisms and targeted therapy capabilities are explored, showcasing their potential in combating cancer cells. Upconverting NPs, which can convert low-energy photons into high-energy emissions, are discussed in the context of cancer treatment. Their applications in PTT are explored, highlighting their potential for precise cancer cell targeting and destruction. Inspired by nature’s mechanisms, biomimetic-based materials for cancer treatment are examined. These materials mimic biological systems to enhance PTT, offering promising avenues for targeted cancer therapy.

Deviated nasal septum (DNS) is a common condition affecting nasal breathing, which is generally treated using septoplasty. However, this invasive surgical method carries potential risks of post-surgical complications. Alternatively, electromechanical reshaping (EMR) is a novel method that has evolved as a non-thermal, minimally invasive option to reshape the cartilage using mechanical pressure and direct current (DC) without significant tissue damage. However, the existing flat and needle electrodes tested in animal tissues have raised significant concerns due to their safety. Thus, herein, we aimed to develop a novel strip electrode configuration and optimize dosimetry to achieve efficient reshaping without compromising its safety. Electric field simulations showed that our novel 5-strip electrode configuration with a thickness of 0.5 mm achieved optimal electric field, requiring minimal current flow compared to flat electrodes. EMR was performed on ex vivo goat cartilage at various dosimetry groups to analyze four-day shape retention. The optimized strip electrode reshaped the ex vivo goat septal cartilage effectively at a dosimetry of 20 mA for 15 minutes, whereas the flat electrode needed 35 mA for 15 minutes. DMMB assay, ATR-FTIR spectroscopy, tensile testing, and histopathology analysis demonstrated reduced tissue damage while supporting increased efficiency and mechanical stability with the strip electrode configuration, emphasizing its safety. Thus, the optimized strip electrode-based EMR emerges as a viable non-invasive approach for reshaping the nasal septal cartilage, which can be used to treat DNS. Further in vivo studies are recommended to validate the long-term safety and efficacy of this technique.

Deviated nasal septum (DNS) is a common condition affecting nasal breathing, which is generally treated using septoplasty. However, this invasive surgical method carries potential risks of post-surgical complications. Alternatively, electromechanical reshaping (EMR) is a novel method that has evolved as a non-thermal, minimally invasive option to reshape the cartilage using mechanical pressure and direct current (DC) without significant tissue damage. However, the existing flat and needle electrodes tested in animal tissues have raised significant concerns due to their safety. Thus, herein, we aimed to develop a novel strip electrode configuration and optimize dosimetry to achieve efficient reshaping without compromising its safety. Electric field simulations showed that our novel 5-strip electrode configuration with a thickness of 0.5 mm achieved optimal electric field, requiring minimal current flow compared to flat electrodes. EMR was performed on ex vivo goat cartilage at various dosimetry groups to analyze four-day shape retention. The optimized strip electrode reshaped the ex vivo goat septal cartilage effectively at a dosimetry of 20 mA for 15 minutes, whereas the flat electrode needed 35 mA for 15 minutes. DMMB assay, ATR-FTIR spectroscopy, tensile testing, and histopathology analysis demonstrated reduced tissue damage while supporting increased efficiency and mechanical stability with the strip electrode configuration, emphasizing its safety. Thus, the optimized strip electrode-based EMR emerges as a viable non-invasive approach for reshaping the nasal septal cartilage, which can be used to treat DNS. Further in vivo studies are recommended to validate the long-term safety and efficacy of this technique.

There is an urgent need of perceptive flexible wearable sensors, for the continuous monitoring of the glucose particularly in a non-invasive way, to control the diabetes at early stages, we have conception of developing non-enzymatic glucose sensing for the detection purpose. Recently, nickel-based metal organic framework (Ni-MOF) has gained a significant importance as a sensing material for label-free, non-enzymatic glucose monitoring using electrochemical sensing techniques. This work, presents a novel state of the art hybrid structure of Ni-MOF consisting of stacked nanosheets embedded with porous nanopillars randomly providing large no. of active sites for the glucose detection. The hybrid structure indicate a close contact between the glucose and the active sites of Ni ions ensuring an efficient glucose sensing. As synthesized Ni-MOF was used, for the potentiometric and amperometric electrochemical detection of the glucose using screen-printed electrode (SPE) which are suitable for flexible sensor applications. With SPE, Ni-MOF shows a wide detection range for glucose from 60 μM to 600 μM with the LOD of 0.28 μM and the sensitivity of 4462.03 μA mM−1 cm−2, which is extremely favorable for glucose detection in sweat and saliva of human. The as developed material has potential as a working electrode on the flexible substrate like polyethylene terephthalate, for sensing glucose in sweat and saliva samples. © 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.

This work demonstrates a low-temperature hybrid bonding integrating copper and Parylene-C for 3-D integration. The Parylene was deposited using a chemical vapor deposition process over electroplated copper bumps followed by chemical mechanical polishing (CMP) to planarize copper/parylene topology and flatten the roughness of a copper surface. The parylene shows a higher tolerance for height topology and surface roughness. The recrystallization of the parylene was performed at 250 °C for 30 min prior to bonding. The copper and parylene materials are then bonded simultaneously at 300 °C. A homogenous bond of copper to copper and parylene to parylene bonding interface without any significant bonding voids was obtained. The tensile and shear bond strength of the bond interface was evaluated using a universal testing machine (UTM) and showed improved strength compared to bonding them separately. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis ensures parylene's thermal stability up to 490 °C, making the substance appropriate for IC packaging. The developed hybrid bonding is well suited for 2.5 and 3-D heterogeneous integration.

This study presents the development and characterization of a novel textile-based wristband sensor for continuous temperature monitoring. The sensor, woven with a blend of polyester-stainless steel and polyester-cotton yarns, exhibited high sensitivity (0.0315/°C) and a rapid response time (∼35 sec). Stainless steel was selected for its excellent electrical conductivity and biocompatibility, crucial for accurate and safe skin contact applications, while polyester and cotton contribute its lightweight, breathable, and durable properties, ensuring prolonged comfort and wearability. Through systematic testing and optimization, the sensor’s sensitivity was fine-tuned by adjusting the number and length of conductive yarns. The study also introduced a theoretical resistance equivalent model, comparing its theoretical sensitivity with experimental findings. The sensor, lightweight and cost-effective, proved comfortable during 8–10 h of continuous wear. This study addresses challenges faced by existing textile temperature sensors and offers a reliable alternative with high linearity, repeatability, and suitability for individuals with sensitive skin.