Scholarlink

<p>Sunlight is a clean and renewable energy source for nanomaterial fabrication; however, its quantitative influence on nanoparticle formation remains insufficiently explored. In this study, copper nanoparticles (CuNPs) were synthesized using an aqueous green tea (<i>Camellia sinensis</i>) extract under natural sunlight, and the relationship between real-time solar irradiance and nanoparticle physicochemical and antimicrobial properties was systematically investigated. UV–Vis spectroscopy indicated rapid photoreduction of Cu<sup>2</sup>⁺ ions, while XRD and TEM analyses revealed predominantly spherical nanoparticles with face-centered cubic copper structure. Statistical analysis of more than 200 particles per sample demonstrated a strong negative correlation (r = − 0.93, <i>p</i> &lt; 0.01) between solar irradiance intensity and particle size, with midday sunlight producing the smallest CuNPs (18.6 ± 3.1&#xa0;nm). HPLC profiling suggested that epigallocatechin gallate (EGCG) is a major phytochemical contributing to photon-assisted electron transfer during reduction. The synthesized CuNPs exhibited good colloidal stability, with a zeta potential of −28.4&#xa0;mV and minimal aggregation over a 30-day period. Antibacterial evaluation showed activity against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>, with minimum inhibitory concentrations of 62.5&#xa0;µg&#xa0;mL⁻<sup>1</sup> and 78.1&#xa0;µg&#xa0;mL⁻<sup>1</sup>, respectively. The antibacterial effect is associated with reactive oxygen species generation and membrane disruption mechanisms, consistent with previous reports. Overall, this study suggests a correlation between solar irradiance and CuNP size, stability, and biological activity, providing a promising laboratory-scale, energy-efficient photochemical approach for nanoparticle synthesis.</p> Graphical Abstract <p>Graphical schematic illustrating the sunlight-driven green synthesis of copper nanoparticles (CuNPs) using aqueous green tea (<i>Camellia sinensis</i>) extract. Variations in natural solar irradiance during morning, midday, and evening influence the photoreduction rate of Cu²⁺ ions, resulting in CuNPs with different sizes and stability. Midday sunlight, associated with the highest photon flux, produces smaller and more uniform CuNPs due to efficient catechin-mediated electron transfer and surface capping. The synthesized CuNPs exhibit pronounced antimicrobial activity against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>, primarily through reactive oxygen species generation and bacterial membrane disruption. The schematic highlights the direct relationship between solar irradiance, nanoparticle physicochemical properties, and biological efficacy, emphasizing sunlight as a clean and renewable driving force for sustainable nanomaterial synthesis.</p> <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Sunlight-driven green synthesis of copper nanoparticles using green tea extract and their antibacterial activity

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年6月15日

查看全文
  • Naveen Pathivada,
  • Gopi Mamidi,
  • Indira Priyadarsini Amancharla,
  • Gunduluru Swathi

摘要

Sunlight is a clean and renewable energy source for nanomaterial fabrication; however, its quantitative influence on nanoparticle formation remains insufficiently explored. In this study, copper nanoparticles (CuNPs) were synthesized using an aqueous green tea (Camellia sinensis) extract under natural sunlight, and the relationship between real-time solar irradiance and nanoparticle physicochemical and antimicrobial properties was systematically investigated. UV–Vis spectroscopy indicated rapid photoreduction of Cu2⁺ ions, while XRD and TEM analyses revealed predominantly spherical nanoparticles with face-centered cubic copper structure. Statistical analysis of more than 200 particles per sample demonstrated a strong negative correlation (r = − 0.93, p < 0.01) between solar irradiance intensity and particle size, with midday sunlight producing the smallest CuNPs (18.6 ± 3.1 nm). HPLC profiling suggested that epigallocatechin gallate (EGCG) is a major phytochemical contributing to photon-assisted electron transfer during reduction. The synthesized CuNPs exhibited good colloidal stability, with a zeta potential of −28.4 mV and minimal aggregation over a 30-day period. Antibacterial evaluation showed activity against Escherichia coli and Staphylococcus aureus, with minimum inhibitory concentrations of 62.5 µg mL⁻1 and 78.1 µg mL⁻1, respectively. The antibacterial effect is associated with reactive oxygen species generation and membrane disruption mechanisms, consistent with previous reports. Overall, this study suggests a correlation between solar irradiance and CuNP size, stability, and biological activity, providing a promising laboratory-scale, energy-efficient photochemical approach for nanoparticle synthesis.

Graphical Abstract

Graphical schematic illustrating the sunlight-driven green synthesis of copper nanoparticles (CuNPs) using aqueous green tea (Camellia sinensis) extract. Variations in natural solar irradiance during morning, midday, and evening influence the photoreduction rate of Cu²⁺ ions, resulting in CuNPs with different sizes and stability. Midday sunlight, associated with the highest photon flux, produces smaller and more uniform CuNPs due to efficient catechin-mediated electron transfer and surface capping. The synthesized CuNPs exhibit pronounced antimicrobial activity against Escherichia coli and Staphylococcus aureus, primarily through reactive oxygen species generation and bacterial membrane disruption. The schematic highlights the direct relationship between solar irradiance, nanoparticle physicochemical properties, and biological efficacy, emphasizing sunlight as a clean and renewable driving force for sustainable nanomaterial synthesis.