Highly Synergistic Sensor of Graphene Electrode Functionalized with Rutile TiO2 Microstructure to Detect L-Tryptophan Compound

ZnO-Enhanced Reduced Graphene Oxide Electrodes from Cocoa Shell: Nanoarchitectonics Platform for Photoelectrocatalytic Detection of Methylene Blue

In this study, we report the successful preparation of reduced graphene oxide modified zinc oxide (rGO-ZnO) composites from cocoa shells. Synthesis of rGO-ZnO was carried out using the Hummer method and thermal reduction. The electrode material was comprehensively characterized using fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy & Energy Dispersive X-ray (SEM-EDX). The photoelectrocatalytic performance of the prepared composite electrodes was evaluated using various electrochemical techniques, including Linear Sweep Voltammetry (LSV), Cyclic Voltammetry (CV), and Multi Pulse Amperometry (MPA). The FTIR analysis of rGO-ZnO exhibited distinct bands corresponding to C-O at 1022 cm-1, C=C at 1600 cm-1, and Zn-O at 455 cm-1. The XRD analysis revealed characteristic peaks at 26.6º, 29.2º, 36.2º, 44.04º, 47.58º, and 64.4º, confirming the presence of key crystalline phases. SEM-EDX analysis of rGO-ZnO revealed a rough surface morphology with bright white and black regions, signifying the coexistence of ZnO and rGO with carbon, oxygen, and zinc contents of 78.98%, 17.46%, and 3.56%, respectively. The investigations involved the photoelectrochemical profiles of methylene blue organic dyes at different concentrations, ranging from 0.5 ppm to 3.0 ppm. The acquired findings offer valuable understanding into the photoelectrocatalytic effectiveness of the composite electrodes containing rGO-ZnO, suggesting their potential use in potential scenarios involving the revitalization of the environment in industrial water systems.

Highly Ecofriendly Inorganic Pesticide Based on TiO2 Incorporated with Nano-Carbon Composites for Phytophthora palmivora Fungus Disinfection

Crop destruction organisms are an essential factor hindering cocoa plants' production yield. It is the biggest problem for cocoa farmers to resolve and reduce the impact of the P. palmivora fungus on cocoa pods. Herein, this study presents the optimization of inorganic pesticides based on nano-carbon self-doped TiO2 (C/TiO2) nanocomposites capable of disinfecting broad-spectrum P. palmivora microorganisms for the practical application of photodisinfection technology. C/TiO2 nanocomposite-based inorganic pesticide has been prepared by sol-gel method to produce nanospray and planted in media containing P. palmivora fungus. To identify the various composition of the C/TiO2 nanospray, they were evaluated by FTIR spectroscopy to observe the functional groups of the nano-carbon and TiO2, which clearly contained -OH (3446-3448 cm-1), C≡C (2366-2370 cm-1), C=O (1797-1799 cm-1), C-H (1425 cm-1), C-O (1163-1203 cm-1), C-H (875-877 cm-1), and Ti-O (875-877 cm-1) groups. Some researchers have reported that nano-carbon significantly changes the band gap energy of TiO2 under visible light and can also be active under dark conditions. This statement is relevant to our experimental results that 0.3% C/TiO2 nanocomposites can inhibit the fungus P. palmivora with a percentage inhibition value of 72.7%. However, the high-performance efficiency proved strong when subjected to visible light irradiation with an inhibition value of 98.6%. Our results indicate that C/TiO2 nanocomposites have great potential in agricultural plant pathogen disinfection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01076-7.

Towards Point-of-Care Manufacturing and Analysis of Immediate-Release 3D Printed Hydrocortisone Tablets for The Treatment of Congenital Adrenal Hyperplasia

Hydrocortisone (HC) is the preferred drug in children with congenital adrenal hyperplasia due to its lower potency as well as fewer reports of side effects. Fused deposition modelling (FDM) 3D printing holds the potential to produce low-cost personalised doses for children at the point of care. However, the compatibility of the thermal process to produce immediate-release bespoke tablets for this thermally labile active is yet to be established. This work aims to develop immediate-release HC tablets using FDM 3D printing and assess drug contents as a critical quality attribute (CQA) using a compact, low-cost near-infrared (NIR) spectroscopy as a process analytical technology (PAT). The FDM 3D printing temperature (140 °C) and drug concentration in the filament (10%-15% w/w) were critical parameters to meet the compendial criteria for drug contents and impurities. Using a compact low-cost NIR spectral device over a wavelength of 900-1700 nm, the drug contents of 3D printed tablets were assessed. Partial least squares (PLS) regression was used to develop individual calibration models to detect HC content in 3D printed tablets of lower drug contents, small caplet design, and relatively complex formula. The models demonstrated the ability to predict HC concentrations over a wide concentration range (0-15% w/w), which was confirmed by HPLC as a reference method. Ultimately, the capability of the NIR model had preceding dose verification performance on HC tablets, with linearity (R² = 0.981) and accuracy (RMSECV = 0.46%). In the future, the integration of 3DP technology with non-destructive PAT techniques will accelerate the adoption of on-demand, individualised dosing in a clinical setting.