Author/Authors :
Lapening ، Melbagrace Research Center for Energy Efficient Materials (RCEEM), Premier Research Institute of Science and Mathematics (PRISM) - Mindanao State University-Iligan Institute of Technology , Rivera ، Rolen Brian Research Center for Energy Efficient Materials (RCEEM), Premier Research Institute of Science and Mathematics (PRISM) - Mindanao State University-Iligan Institute of Technology , Unabia ، Romnick IT and Physics Department - College of Natural Sciences and Mathematics - Mindanao State University - General Santos , Reazo ، Renzo Luis Research Center for Energy Efficient Materials (RCEEM), Premier Research Institute of Science and Mathematics (PRISM) - Mindanao State University-Iligan Institute of Technology , Omping ، Jahor Research Center for Energy Efficient Materials (RCEEM), Premier Research Institute of Science and Mathematics (PRISM) - Mindanao State University-Iligan Institute of Technology , Lumod ، Ryan Research Center for Energy Efficient Materials (RCEEM), Premier Research Institute of Science and Mathematics (PRISM) - MSU-Iligan Institute of Technology , Ruda ، Archie Research Center on Energy Efficient Materials (RCEEM), Premier Research Institute in Science and Mathematics (PRISM) - Mindanao State University −Iligan Institute of Technology , Ceniza ، Amyzz Department of Physical Sciences and Mathematics - College of Marine and Allied Sciences - Mindanao State University at Naawan , Sayson ، Noel Lito Department of Physics - Mindanao State University-Iligan Institute of Technology , Latayada ، Felmer Department of Chemistry - Caraga State University , Capangpangan ، Rey Mindanao State University, Naawan Campus , Dumancas ، Gerard Department of Chemistry - North Carolina Agricultural and Technical State University , Lubguban ، Arnold Center for Sustainable Polymers - MSU-Iligan Institute of Technology , Malaluan ، Roberto Center for Sustainable Polymers - MSU-Iligan Institute of Technology , Hosseini-Bandegharae ، Ahmad Faculty of Chemistry - Semnan University , Petalcorin Jr. ، Gaudencio Department of Mathematics and Statistics - Mindanao State University-Iligan Institute of Technology , Alguno ، Arnold Department of Materials and Resources Engineering and Technology - MSU-Iligan Institute of Technology
Abstract :
Polyethylene glycol-capped gold nanoparticles (PEG-AuNPs) are highly promising for biological and medical applications due to their biocompatibility, enhanced stability, and low cytotoxicity. The successful synthesis method presented here was a one-step process where both reduction and functionalization took place simultaneously using lower concentrations of gold precursors. Unlike previous methods that used higher concentrations ( 10 mM) and did not explore varying molar ratios, this study investigates the physicochemical properties of PEG-AuNPs synthesized with precursor concentrations ranging from 0.5 mM to 5 mM. Transmission electron microscopy images revealed an increase in the particle sizes of spherical nanoparticles from 14.5nm to 46.7nm as the precursor concentration increased, consistent with dynamic light scattering measurements. UV-Vis spectroscopy confirmed that spherical nanoparticles were formed having surface plasmon resonance peaks ranging from 520-530nm. Fourier transform infrared spectroscopy analyses revealed the interactions between PEG ligands and gold nanoparticles where some specific peaks exist around 1632cm⁻¹ while the O-H stretching peak shifted from approximately 3400 cm⁻¹ to about 3490 cm⁻¹, confirming successful surface modification. Photoluminescence spectroscopy revealed maximum emission particularly observed at the lowest precursor concentration (0.5 mM). Importantly, the synthesized PEG-AuNPs even at the lowest precursor concentration of 0.5mM demonstrated exceptional stability in saline conditions, maintaining dispersion even in the presence of 500 mM NaCl. This one-step synthesis method at reduced precursor concentrations not only enables precise control over the nanoparticles’ size and optical properties but also enhances their stability and tunable fluorescence. These findings present a scalable and versatile approach for the tailored synthesis of PEG-AuNPs, making them suitable for advanced biological and medical sensing applications.
Keywords :
Gold nanoparticles , Precursor concentration , One , step synthesis , polyethylene glycol
