Makassar – A flower commonly known for its vibrant blue color and herbal benefits may hold the key to a greener future in nanotechnology. A study conducted by Satria Putra Jaya Negara and Andi Eka Kartika from Makassar State University demonstrates that butterfly pea flower (Clitoria ternatea) extract can be used to synthesize gold nanoparticles (AuNPs) through an environmentally friendly green synthesis approach. Published in 2026 in the East Asian Journal of Multidisciplinary Research (EAJMR), the research highlights how plant-based materials can replace hazardous chemicals while producing high-quality gold nanoparticles with promising applications in medicine, environmental science, and advanced technology.
Nanotechnology has become one of the fastest-growing scientific fields because materials engineered at the nanoscale exhibit unique physical, chemical, and optical properties that differ significantly from those of bulk materials. Among various nanomaterials, gold nanoparticles have attracted considerable attention due to their excellent chemical stability, high biocompatibility, and remarkable optical characteristics. These properties make AuNPs valuable for biosensors, medical imaging, drug delivery systems, catalysis, environmental monitoring, and electronic devices.
Despite their broad applications, conventional methods for synthesizing gold nanoparticles generally rely on hazardous reducing agents and organic solvents that may threaten both environmental sustainability and human health. As concerns over chemical pollution continue to grow, researchers worldwide have been seeking safer alternatives. Green synthesis has emerged as one of the most promising approaches because it utilizes natural biological resources, particularly plant extracts, as environmentally friendly reducing and stabilizing agents.
Butterfly pea flower was selected for this study because it is naturally rich in flavonoids, anthocyanins, tannins, and other polyphenolic compounds with strong antioxidant properties. These phytochemicals are capable of donating electrons to convert gold ions (Au³⁺) into metallic gold nanoparticles while simultaneously coating the nanoparticle surface to prevent excessive aggregation. Consequently, the plant extract serves two important functions during synthesis: reducing metal ions and stabilizing the nanoparticles without requiring synthetic chemicals.
The researchers carried out a laboratory experiment using methanolic butterfly pea flower extract as the natural bioreducing agent. Gold precursor solutions were reacted with the extract under five different reaction times—0, 30, 60, 90, and 120 minutes—to determine the optimal conditions for nanoparticle formation. The synthesized nanoparticles were characterized using UV–Visible spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM), allowing the researchers to evaluate their optical properties, functional groups, and particle morphology. All experiments were performed in triplicate to ensure reliability and reproducibility.
One of the first indicators of successful nanoparticle formation was a visible color change in the reaction mixture, which gradually transformed from pale yellow into ruby red. This distinctive color is widely recognized as evidence of gold nanoparticle formation. UV–Visible spectroscopy further confirmed the synthesis by detecting a characteristic Surface Plasmon Resonance (SPR) absorption peak centered at approximately 545.5 nanometers. The highest absorbance was recorded after 90 minutes, indicating that this reaction time produced the largest quantity of stable nanoparticles. When the reaction continued for 120 minutes, absorbance decreased slightly, suggesting that most gold ions had already been converted and that slight particle aggregation had begun to occur.
FTIR analysis revealed several important functional groups within the butterfly pea flower extract, including hydroxyl (O–H), methylene (C–H), aromatic carbon double bonds (C=C), and C–O groups. These functional groups play essential roles in transferring electrons during the reduction process and forming a protective organic layer around the nanoparticles. This natural coating improves nanoparticle stability and minimizes excessive aggregation, demonstrating that butterfly pea flower extract functions effectively as both a reducing and capping agent.
Scanning Electron Microscopy further demonstrated that the synthesized nanoparticles possessed nanoscale dimensions with predominantly semi-spherical and irregular polygonal shapes. Although minor agglomeration was observed, the nanoparticles remained relatively well dispersed, indicating that the plant-derived biomolecules successfully stabilized the particles throughout the synthesis process. These morphological observations closely matched the optical results obtained through UV–Visible spectroscopy, confirming the effectiveness of the green synthesis method.
According to Satria Putra Jaya Negara and Andi Eka Kartika from Makassar State University, the findings demonstrate that butterfly pea flower represents a promising natural resource for sustainable nanotechnology development. Using plant extracts eliminates the need for toxic reducing chemicals while providing a simple, cost-effective, and environmentally responsible method for producing gold nanoparticles. Such an approach supports global efforts to develop greener manufacturing technologies and reduce the environmental impact of advanced material production.
The implications of this research extend across multiple scientific and industrial sectors. Gold nanoparticles synthesized through environmentally friendly methods could be applied in biomedical diagnostics, targeted drug delivery, cancer therapy, biosensors, environmental monitoring, water purification technologies, catalysis, and advanced electronic devices. More importantly, the study demonstrates that Indonesia's abundant biodiversity can serve as a valuable source of sustainable raw materials for high-value nanotechnology, opening new opportunities for innovation while supporting environmental conservation and the development of green industries.
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Research Source
Article Title: Green Synthesis of Gold Nanoparticles (AuNPs) Using Butterfly Pea Flower (Clitoria ternatea) Extract: Effect of Reaction Time on Particle Characteristics
Journal: East Asian Journal of Multidisciplinary Research (EAJMR), Vol. 5, No. 6, 2026.
DOI: https://doi.org/10.55927/eajmr.v5i6.196
Journal Link: https://journaleajmr.my.id/index.php/eajmr
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