Document Type : Research Paper
Authors
1
Research Center for Energy Efficient Materials (RCEEM), Premier Research Institute of Science and Mathematics (PRISM), Mindanao State University-Iligan Institute of Technology, 9200 Iligan City, Philippines
2
IT and Physics Department, College of Natural Sciences and Mathematics, Mindanao State University - General Santos, General Santos City, 9500 South Cotabato, Philippines
3
Research Center for Energy Efficient Materials (RCEEM), Premier Research Institute of Science and Mathematics (PRISM), MSU-Iligan Institute of Technology, 9200 Iligan City, Philippines
4
Research Center on Energy Efficient Materials (RCEEM), Premier Research Institute in Science and Mathematics (PRISM), Mindanao State University − Iligan Institute of Technology, Iligan City 9200, Philippines
5
Department of Physical Sciences and Mathematics, College of Marine and Allied Sciences, Mindanao State University at Naawan, Naawan 9023, Misamis Oriental, Philippines
6
Department of Physics, Mindanao State University-Iligan Institute of Technology, 9200 Iligan City, Philippines
7
Department of Chemistry, Caraga State University, Butuan City 8600, Philippines
8
Mindanao State University at Naawan Campus, Naawan Misamis Oriental 9023, Philippines
9
Department of Chemistry, New Science Building, North Carolina Agricultural and Technical State University 1601 E. Market Street, Greensboro, NC 27411 USA
10
Center for Sustainable Polymers, MSU-Iligan Institute of Technology, Iligan City 9200, Philippines
11
Faculty of Chemistry, Semnan University, Semnan, the Islamic Republic of Iran
12
Department of Mathematics and Statistics, Mindanao State University-Iligan Institute of Technology, 9200 Iligan City, Philippines
13
Department of Materials and Resources Engineering and Technology, MSU-Iligan Institute of Technology, Iligan City 9200, Philippines
10.22059/jufgnsm.2024.02.04
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.
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