3rd World Conference on Materials Science and Nanotechnology

Recent advances in enhancing the sensitivity of capacitive pressure sensors have primarily focused on developing dielectric layers with intricate surface or porous structures or employing materials with high dielectric constants. However, these approaches have proven effective mainly within low pressure ranges (up to 3 kPa). To address this limitation, we introduce an elastomer-based pressure sensor leveraging a novel and cost-effective fabrication process, designed for health-monitoring applications. This sensor employs a water-soluble polyvinyl alcohol (PVA) mold, created via 3D printing, to cast a polydimethylsiloxane (PDMS) matrix infused with graphene nanoplatelets. Upon hardening, the PVA mold is dissolved in water, yielding a flexible, stretchable, and electrically conductive PDMS/graphene composite foam. The 3D printing technique allows precise control over the mold's pore size, facilitating the tuning of the sensor's stiffness and sensitivity. The foam is sandwiched between two conductive layers with an insulator, forming a capacitor whose capacitance changes due to variations in conductivity and distance between electrodes under pressure.Through material, electrical, and mechanical characterization, we demonstrate the sensor's superior response. This study presents a simplified analytical model to predict optimal graphene nanoplatelet doping levels, enhancing the sensor's hybrid piezoresistive and piezocapacitive responses. Our findings indicate that this approach significantly improves sensitivity across a wide pressure range, making it suitable for detecting subtle pressures such as temporal arterial pulses as well as larger forces like footsteps.

The solution processed thin film transistors have wide range of applications in research and technology in flexible displays, low power electronics, circuits and sensors due to the advantages of low leakage currents, high surface homogeneity, adaptability to various process, reproducibility and high reliability. The TFT applications are extended to biosensing and for biochemistry analysis due to its ability to detect molecules, ions, peptides, lipids, oligonucleotides and DNA. The need of low cost biosensing, direct and rapid detection, has attracted thin film transistors towards biosensing due to their high sensitivity sensing, miniaturization, low cost fabrication and room temperature processing. TFT biosensors can easily detect tiny electrical charge difference from bio molecules with very high sensitivity current or voltage and the same transistor can be used for signal readout. The low cost and low operating voltage a-IGZO TFT with top gate top contact architecture (TGTC) is processed with silver as top gated material( screen printed) as sensing layer for protein detection with various concentrations of streptavidin. APTES is functionalized on silver gate followed by functionalization of Sulfo-NHS biotin for sensing various molar concentrations of streptavidin as a protein sensor. The operating voltage is almost Vgs= 5V and Vds=2V. TFT exhibits the electrical properties of, Vth=0.66V, Ion/Ioff=0.9x106 with mobility of 0.15 cm2/v-s.

Dimethyl fumarate (DMF) is a first line oral medication for the treatment of multiple sclerosis (MS), associated with several adverse events. Intranasal delivery of drug could potentially alleviate the adverse events and enhance the therapeutic efficacy. The current study aimed to formulate an oil in water (o/w) nanoemulsion (NE) by solvent evaporation self-nanoemulsification method. NEs encapsulating DMF with carvacrol (CV), a neuroprotective essential oil, for synergistic therapeutic effect were intended for intranasal administration. Chitosan was employed as a surfactant, owing to its mucoadhesive properties. FT-IR and TGA analyses revealed an increased stability of DMF due to the presence of CV. Response surface methodology was used for the optimization of NEs by applying Central Composite Design model. Surfactant concentration, oil to surfactant ratio, and probe sonication time were set as independent variables whereas, mean droplet size, PDI, and zeta potential were set as dependent variables. The selected formulation out of 15, had a mean size below 250 nm and a PDI less than 0.5 that was sustained at refrigerated temperatures for over 3 months. Drug content of selected formulation was found to be more than 65% despite the volatile nature of DMF and CV. Moreover, 50uM concentration of NEs showed good cell viability in MTT assay mediated cell viability studies. Permeability studies on RPMI 2650 nasal cell lines revealed the permeation of 86% of DMF in 3 hours. It was concluded that DMF-CV NEs are a promising therapeutic cocktail for MS that could reduce the adverse events related to DMF, enhancing therapeutic efficacy as well as patient compliance and medication adherence.

Anisotropic (irregular-shaped or branched) plasmonic nanomaterials have garnered extensive research interest because of their enhanced-cum-unique optical and electronic properties. Such peculiar properties make them attractive for several applications such as photovoltaic technology, optoelectronics, bio- and chemical sensing and nanomedicine. Fine tuning the shape and production of good quality i.e., uniformity in morphology and size, of anisotropic nanomaterials is a challenge in order that they can be used in varied applications. Bulk wet chemical synthesis suffers from drawbacks such as poor control over reagent addition, mixing, reaction time and temperature leading to polydispersity in nanomaterials and hence non-reproducibility from one batch to another. Herein, we present a fluidic approach to synthesize anisotropic gold (Au) nanostructures in a continuous-flow using a flow reactor made by three dimensional (3D)-printing technology. Stereolithography (SLA), a type of 3D-printing technique was used to fabricate the reactor. Three different reducing agents (ascorbic acid, hydroxyquinone and polyvinylpyrrolidone) of different concentrations were used to synthesize the plasmonic nanomaterials. The nanomaterials were extensively characterized by spectroscopic and microscopy methods that revealed flower-, urchin- and spindle-shaped morphologies of Au nanomaterials.