Ultrascan digital camera

AgNPs were first characterised by ultraviolet–visible spectrophotometry (UV-Vis, BioTek Synergy 4 Microplate Reader, Bad Friedrichshall, Germany) through localised surface plasmon resonance (LSPR) absorbance measurement, scanned between 300 nm and 1000 nm, with 2 nm steps. Selected AgNPs were then characterised using high-resolution TEM (FEI Titan 80) to evaluate the shape and size distribution of the resulting AgNPs. Samples were drop-coated onto the Formvar carbon-coated copper grids with a 200 µm mesh size (Agar Scientific, Essex, UK) and dried over 24 h. Images were obtained using the FEI Titan 80 operated at 300 kV using a field emission electron gun equipped with a Gatan Ultrascan digital camera. ImageJ software was utilised to measure an average of 200 NPs to evaluate size distribution. Finally, energy-dispersive X-ray spectrometry (EDS) was used to analyse the elemental composition of the synthesised NPs. For this method, 5 µL of the samples was drop-coated trice onto polished aluminium slides and dried in the oven at 60 °C for 1 h. An electron microscope (Hitachi 3000, Tokyo, Japan) at 15 kV accelerating voltage and a working distance of 2 mm was used to obtain the EDS spectra of the samples.

The resulting AgNPs were characterised based following the study by Alves and Murray [3 (link)]. Ultraviolet–visible spectrophotometry (UV-Vis, BioTek Synergy 4 Microplate Reader, Bad Friedrichshall, Germany) was first used to measure the localised surface plasmon resonance (LSPR) absorbance. AgNPs were scanned between 300 nm and 1000 nm, with 2 nm steps. Afterwards, transmission electron microscopy (TEM, JEOL JEM 2100 Field Emission Electron Microscope, Tokyo, Japan) was used to evaluate the shape and size distribution of the AgNPs. Samples were drop-coated onto Formvar carbon-coated copper grids with a 200 µm mesh size and dried over 24 h. Images were obtained using a JEOL JEM 2100 Field Emission Electron Microscope operated at 200 kV with a field emission electron gun equipped with a Gatan Ultrascan digital camera. An average of 200 NPs was recorded from several TEM images, with AxioVision Rel 4.8 software used to evaluate size distribution. Furthermore, the elemental composition was analysed using energy dispersive X-ray spectrometry (EDX, Hitachi 3000, Tokyo, Japan). Five microliters of the samples was drop-coated onto polished aluminium slides and dried in the oven at 60 °C for 1 h, thrice. A Hitachi 3000 electron microscope with EDX capability at 15 kV accelerating voltage and a working distance of 2 mm was used to obtain the ED spectra of the samples.