Defining acceptance criteria for silver nanoparticles: correlating synthesis quality with biological outcomes in an In Vitro Lung Cancer Model

Abstract

Lung cancer remains a leading cause of cancer-related mortality worldwide, underscoring the need for innovative therapeutic strategies. This study explores the development and evaluation of silver nanoparticles (AgNPs) synthesized under optimized heating and cooling protocols to refine their physicochemical properties for antitumor applications. The AgNPs were synthesized using chemical synthesis using a reduction and bottom-up strategy. Eight synthesis protocols were optimized, and key parameters, such as particle size, morphology, and stability, were systematically characterized using UV–visible spectroscopy, dynamic light scattering, nanoparticle tracking analysis, and electron microscopy. Selected nanoparticles were evaluated for their cytotoxic effects on A549 lung adenocarcinoma cells, demonstrating dose- and time-dependent reductions in cell viability. Mechanistic insights revealed early apoptosis, assessed using flow cytometry by detecting phosphatidylserine externalization with Annexin V staining, propidium iodide uptake for membrane integrity, and lactate dehydrogenase release for cell damage. Surface coatings played a pivotal role, with citrate-stabilized AgNPs exhibiting rapid cytotoxicity and PVA-stabilized AgNPs showing sustained effects. This study underscores the importance of tailoring synthesis conditions to achieve reproducible and biologically effective AgNPs, providing a foundation for advancing nanotechnology-based cancer therapies.