Publicação
Green synthesis of Ag and Au nanoparticles using Thymlaea extract: morphology, antioxidant activity, and SERS detection of penicillin G
| Resumo: | This study describes the green synthesis of silver and gold colloids via the reduction of Ag(I) and Au(III) in the presence of distinct aqueous plant extracts, as well as the influence of various reaction parameters, such as reaction time, pH, and extract concentration, on the morphology, size, and stability of the nanoparticles. The method employed led to the formation of stable colloids containing polydisperse silver and gold nanoparticles, which were applied to the SERS detection of benzylpenicillin, a natural β-lactam antibiotic also known as penicillin G (PG). Our results show that all Ag/Au colloids synthesised with Thymelaea plant extract exhibit effective SERS activity for PG detection at a concentration of 10−3 M, without significant interference from chemical adsorbates originating from the extracts. The assessment of antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay revealed that AgNPs (IC₅₀ = 12 μg/mL) and AuNPs (IC₅₀ = 20 μg/mL) exhibit superior activity compared to the crude aqueous extract (IC₅₀ = 30 μg/mL). Transmission electron microscopy (TEM) analysis showed size variations of the nanoparticles depending on the concentration: for AgNPs, spherical particles with diameters of 15.0 nm (2 mg/mL), 20.4 nm (3 mg/mL), 23.5 nm (4 mg/mL), and 26.6 nm (5 mg/mL), and for AuNPs, spherical particles with average diameters of 17.2 nm (5 mg/mL), 27.3 nm (4 mg/mL), 32.7 nm (3 mg/mL), and 76.5 nm (2 mg/mL). Zeta potential measurements confirmed their stability, with all nanoparticles exhibiting negative surface charges. Moreover, pH variations had a minimal impact on their morphology. |
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| Autores principais: | Fernine, Yasmine |
| Outros Autores: | Hjoujia, Kaoutar; Messaoudi, Noureddine El; Martins, Natércia C. T.; Almehizia, Abdulrahman A.; Trindade, Tito; Taleb, Mustapha |
| Assunto: | Green synthesis Thymelaea plant extract AgNPs Au NPs SERS DPPH assay |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | This study describes the green synthesis of silver and gold colloids via the reduction of Ag(I) and Au(III) in the presence of distinct aqueous plant extracts, as well as the influence of various reaction parameters, such as reaction time, pH, and extract concentration, on the morphology, size, and stability of the nanoparticles. The method employed led to the formation of stable colloids containing polydisperse silver and gold nanoparticles, which were applied to the SERS detection of benzylpenicillin, a natural β-lactam antibiotic also known as penicillin G (PG). Our results show that all Ag/Au colloids synthesised with Thymelaea plant extract exhibit effective SERS activity for PG detection at a concentration of 10−3 M, without significant interference from chemical adsorbates originating from the extracts. The assessment of antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay revealed that AgNPs (IC₅₀ = 12 μg/mL) and AuNPs (IC₅₀ = 20 μg/mL) exhibit superior activity compared to the crude aqueous extract (IC₅₀ = 30 μg/mL). Transmission electron microscopy (TEM) analysis showed size variations of the nanoparticles depending on the concentration: for AgNPs, spherical particles with diameters of 15.0 nm (2 mg/mL), 20.4 nm (3 mg/mL), 23.5 nm (4 mg/mL), and 26.6 nm (5 mg/mL), and for AuNPs, spherical particles with average diameters of 17.2 nm (5 mg/mL), 27.3 nm (4 mg/mL), 32.7 nm (3 mg/mL), and 76.5 nm (2 mg/mL). Zeta potential measurements confirmed their stability, with all nanoparticles exhibiting negative surface charges. Moreover, pH variations had a minimal impact on their morphology. |
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