Helium: Journal of Science and Applied Chemistry

Silver Nanoparticles in Point-of-Care Diagnostics: Enhancing Sensitivity, Selectivity, and Future Prospects

Martina Asti Rahayu — 2025-12-01

Silver nanoparticles (AgNPs) have emerged as indispensable nanomaterials for point-of-care (POC) medical diagnostics, due to their unique optical, electrical, and chemical properties that enhance sensor sensitivity, selectivity, and stability. This review systematically discusses the fundamental physicochemical characteristics of AgNPs, with emphasis on surface plasmon resonance (SPR) and its role in signal amplification in techniques such as surface-enhanced Raman spectroscopy (SERS), electrochemical biosensors, and immunosensors. Special attention is given to how synthesis strategies, including chemical, physical, and green, affect nanoparticle uniformity, biocompatibility, and functionalization potential. The review also compares surface modification approaches, including polymer coatings for stability, aptamer/antibody conjugation for specificity, and core–shell architectures for fluorescence enhancement, highlighting their impact on biomarker detection in complex biological matrices. By critically analyzing current challenges such as aggregation, oxidation, and nonspecific binding, the paper synthesizes recent advances in antifouling strategies, scalable production, and integration of AgNPs into portable and wearable diagnostic platforms. Unlike previous reviews, this work consolidates developments across synthesis, surface chemistry, and device engineering, and provides a forward-looking perspective on multiparametric and theragnostic applications. Overall, the paper underlines the importance of multidisciplinary collaboration to accelerate the translation of AgNPs-based sensors into clinically viable POC technologies for personalized healthcare and early disease detection.

Migration of Bisphenol A from Canned Sardines into Food Simulants: Effect of Temperature and Concentration

Alfin Ghanesa Putra — 2025-12-01

Epoxy resin coatings containing Bisphenol A (BPA) are widely used in canned food packaging, including sardine cans. They may pose a risk of chemical migration into food products under specific conditions. This study aimed to evaluate BPA migration into food simulants, acetic acid (1%, 3%, and 10%) and ethanol (10%, 20%, and 50%), at three temperatures (60 °C, 100 °C, and 121 °C). Migration levels were quantified using High-Performance Liquid Chromatography (HPLC) with UV-Vis detection. Preliminary analysis of five sardine can brands revealed BPA concentrations ranging from 0.0052 to 0.0487 mg/kg. Results demonstrated a significant increase in BPA migration with both simulant concentration and temperature. In ethanol, migration increased by 437% when the concentration rose from 10% to 50% at 121 °C, while a 92% increase was observed in acetic acid from 1% to 10% under the same conditions. Temperature had a more pronounced effect: BPA migration in 20% ethanol rose by 3,714% between 60 °C and 121 °C. Migration in 3% acetic acid increased from undetectable to 0.1515 mg/kg across the same temperature range. These findings indicate that BPA migration is significantly influenced by simulant type, concentration, and temperature, underscoring the necessity for stringent control over packaging conditions to ensure food safety.

Anti-cholesterol Activity of Kemuning Leaf Extract (Murraya paniculata (L.) Jack.) Using Different Extraction Methods and Solvents

Ardhalya Octarizha — 2025-12-01

High cholesterol levels may accumulate in blood vessels, causing blockages. Reducing cholesterol levels using biological materials is an essential area of research currently to minimize the impact of chemical drugs. One of the biological materials with potential as an anti-cholesterol is the Kemuning plant (Murraya paniculata (L.) Jack). This study aims to determine the content of secondary metabolites, total phenolic content, total flavonoid content, and anti-cholesterol activity of Kemuning leaf extract, with variations in extraction methods and solvents. The extraction methods used were ultrasound-assisted extraction (UAE) and maceration. The solvents used in this study had different polarities, namely 96% ethanol, ethyl acetate, and n-hexane. The extract obtained from variations in extraction methods and solvents was tested for phytochemistry, total phenolics, total flavonoids, and in vitro anti-cholesterol activity using the Liebermann-Burchard method. The results showed that Kemuning leaf extract contained secondary metabolite compounds with anti-cholesterol activity. The best extraction method for secondary metabolites was the UAE method using 96% ethanol; however, the best EC50 value was obtained from maceration with ethyl acetate. The total phenolic content of the 96% ethanol extract of Kemuning leaf using the UAE method was 61.48 mg Gallic Acid Equivalent (GAE/g extract), the total flavonoid content was 100.77 mg Quercetin Equivalent (QE/g extract), and the anti-cholesterol activity had an EC₅₀ of 13.03 µg/mL.