Green synthesis of gold nanoparticles using Telfairia occidentalis leaf extract and evaluation of their antioxidant activity for possible industrial applications

Daniel B. Tsado; Muhammed M. Ndamitso; Yahaya A. Iyaka; John O. Jacob; Saheed Mustapha

doi:10.46481/jnsps.2026.3708

Authors

Daniel B. Tsado
[email protected]

Department of Chemistry, Federal University of Technology, PMB 65, Gidan Kwano Campus, Minna, Niger State, Nigeria
Muhammed M. Ndamitso
Department of Chemistry, Federal University of Technology, PMB 65, Gidan Kwano Campus, Minna, Niger State, Nigeria;

Nanotechnology Research Group, Center for Genetic Engineering and Biotechnology, Federal University of Technology, Minna, PMB 65, Niger State, Nigeria
Yahaya A. Iyaka
Department of Chemistry, Federal University of Technology, PMB 65, Gidan Kwano Campus, Minna, Niger State, Nigeria
John O. Jacob
Department of Chemistry, Federal University of Technology, PMB 65, Gidan Kwano Campus, Minna, Niger State, Nigeria
Saheed Mustapha
Department of Chemistry, Federal University of Technology, PMB 65, Gidan Kwano Campus, Minna, Niger State, Nigeria;

Nanotechnology Research Group, Center for Genetic Engineering and Biotechnology, Federal University of Technology, Minna, PMB 65, Niger State, Nigeria

Keywords:

Green synthesis, Gold nanoparticles, Telfairia occidentalis, Phytochemical screening, Antioxidant activity

Abstract

An investigation was conducted on the green synthesis of gold nanoparticles (AuNPs) using aqueous Telfairia occidentalis leaf extract as both the reducing and stabilizing agent. Following preliminary phytochemical analysis, AuNPs were synthesized by reacting aqueous tetrachloroauric acid trihydrate with the extract under controlled conditions and characterized using several analytical techniques. The UV-visible spectrum exhibited a surface plasmon resonance (SPR) band at 547.92 nm, and Fourier-transform infrared (FTIR) spectroscopy revealed hydroxyl and amide functional groups, supporting stabilization by polyphenols and proteins. High-resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED) supported a quasi-spherical morphology and high crystallinity, with a mean diameter of 25.89 ± 7.53 nm, a size range of 10.81--48.31 nm, and a median diameter of 25.26 nm (n = 108), as determined using ImageJ; energy-dispersive X-ray spectroscopy (EDS) confirmed the elemental composition and predominance of gold. Antioxidant capacity evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), and lipid peroxidation inhibition assays was concentration dependent. At 100 mu g/mL, AuNPs gave 68.20 ± 0.20% DPPH inhibition versus 91.66 ± 0.26% for ascorbic acid, 75.81 ± 0.18% FRAP versus 95.88 ± 0.38%, and 65.90 ± 0.40% lipid-peroxidation inhibition versus 89.25 ± 0.40%. The findings indicate promising in vitro antioxidant activity, although safety, stability, and application-specific performance require further validation before biomedical or industrial use.

Dimensions

REFERENCES

[1] F. Eker, E. Akdaşçi, H. Duman, M. Bechelany & S. Karav, ``Gold nanoparticles in nanomedicine: unique properties and therapeutic potential'', Nanomaterials 14 (2024) 1854. https://doi.org/10.3390/nano14221854.

[2] M. R. Kumalasari, R. Alfanaar & A. S. Andreani, ``Gold nanoparticles (AuNPs): A versatile material for biosensor application'', Talanta Open 9 (2024) 100327. https://doi.org/10.1016/j.talo.2024.100327.

[3] H. Ahari, M. Fakhrabadipour, S. Paidari, G. Goksen & B. Xu, ``Role of AuNPs in active food packaging improvement: A review'', Molecules 27 (2022) 8027. https://doi.org/10.3390/molecules27228027.

[4] B. A. Suliasih, S. Budi & H. Katas, ``Synthesis and application of gold nanoparticles as antioxidants'', PHARMACIA 71 (2024) 1. https://doi.org/10.3897/pharmacia.71.e112322.

[5] P. B. Santhosh, J. Genova & H. Chamati, ``Green synthesis of gold nanoparticles: an eco-friendly approach'', Chemistry (Switzerland) 4 (2022) 345. https://doi.org/10.3390/chemistry4020026.

[6] Ł. Niżnik, M. Noga, D. Kobylarz, A. Frydrych, A. Krośniak, L. Kapka-Skrzypczak & K. Jurowski, ``Gold nanoparticles (AuNPs)-toxicity, safety and green synthesis: A critical review'', International Journal of Molecular Sciences 25 (2024) 4057. https://doi.org/10.3390/ijms25074057.

[7] J. O. Adeyemi, A. O. Oriola, D. C. Onwudiwe & A. O. Oyedeji, ``Plant extracts mediated metal-based nanoparticles: synthesis and biological applications'', Biomolecules 12 (2022) 627. https://doi.org/10.3390/biom12050627.

[8] N. S. Alsaiari, F. M. Alzahrani, A. Amari, H. Osman, H. N. Harharah, N. Elboughdiri & M. A. Tahoon, ``Plant and microbial approaches as green methods for the synthesis of nanomaterials: synthesis, applications, and future perspectives'', Molecules (Basel, Switzerland) 28 (2023) 463. https://doi.org/10.3390/molecules28010463.

[9] A. S. Jain, P. S. Pawar, A. Sarkar, V. Junnuthula & S. Dyawanapelly, ``Bionanofactories for green synthesis of silver nanoparticles: toward antimicrobial applications'', International Journal of Molecular Sciences 22 (2021) 11993. https://doi.org/10.3390/ijms222111993.

[10] A. Timoszyk & R. Grochowalska, ``Mechanism and antibacterial activity of gold nanoparticles (aunps) functionalized with natural compounds from plants'', Pharmaceutics 14 (2022) 2599. https://doi.org/10.3390/pharmaceutics14122599.

[11] K. K. Bharadwaj, B. Rabha, S. Pati, T. Sarkar, B. K. Choudhury, A. Barman, D. Bhattacharjya, A. Srivastava, D. Baishya & H. A. Edinur, ``Green synthesis of gold nanoparticles using plant extracts as beneficial prospect for cancer theranostics'', Molecules 26 (2021) 6389. https://doi.org/10.3390/molecules26216389.

[12] M. S. Kiran, C. R. Rajith Kumar, U. R. Shwetha, H. S. Onkarappa, V. S. Betageri & M. S. Latha, ``Green synthesis and characterization of gold nanoparticles from Moringa oleifera leaves and assessment of antioxidant, antidiabetic and anticancer properties'', Chemical Data Collections 33 (2021) 100714. https://doi.org/10.1016/j.cdc.2021.100714.

[13] R. A. Pinho, D. P. S. Haupenthal, P. E. Fauser, A. Thirupathi & P. C. L. Silveira, ``Gold nanoparticle-based therapy for muscle inflammation and oxidative stress'', Journal of Inflammation Research 15 (2022) 3219. https://doi.org/10.2147/JIR.S327292.

[14] S. Fallah, E. Yusefi-Tanha & J. R. Peralta-Videa, ``Interaction of nanoparticles and reactive oxygen species and their impact on macromolecules and plant production'', Plant Nano Biology 10 (2024) 100105. https://doi.org/10.1016/j.plana.2024.100105.

[15] S. A. Siddiqui, S. Khan, M. Mehdizadeh, N. A. Bahmid, D. N. Adli, T. R. Walker, R. Perestrelo & J. S. Câmara, ``Phytochemicals and bioactive constituents in food packaging - A systematic review'', Heliyon 9 (2023) e21196. https://doi.org/10.1016/j.heliyon.2023.e21196.

[16] N. Chaachouay & L. Zidane, ``Plant-derived natural products: a source for drug discovery and development'', Drugs and Drug Candidates 3 (2024) 184. https://doi.org/10.3390/ddc3010011.

[17] A. Pugazhendhi, M. A. Alshehri, S. Kandasamy, P. K. Sarangi & A. Sharma, ``Deciphering the importance of nanoencapsulation to improve the availability of bioactive molecules in food sources to the human body'', Food Chemistry 464 (2025) 141762. https://doi.org/10.1016/j.foodchem.2024.141762.

[18] R. Puttasiddaiah, R. Lakshminarayana, N. L. Somashekar, V. K. Gupta, B. S. Inbaraj, Z. Usmani, V. B. Raghavendra, K. Sridhar & M. Sharma, ``Advances in nanofabrication technology for nutraceuticals: New insights and future trends'', Bioengineering (Basel, Switzerland) 9 (2022) 478. https://doi.org/10.3390/bioengineering9090478.

[19] A. Rezagholizade-shirvan, M. Soltani, S. Shokri, R. Radfar, M. Arab & E. Shamloo, ``Bioactive compound encapsulation: Characteristics, applications in food systems, and implications for human health'', Food Chemistry: X 24 (2024) 101953. https://doi.org/10.1016/j.fochx.2024.101953.

[20] X. Guo, L. Li, Y. Qi, J. Su, X. Ou, M. Lv, Y. Jin, X. Han, Y. Zhang, H. Wu, R. Chen & X. Wang, ``Green-synthesized antibacterial and unidirectional water-permeable polylactic acid/ZnO composite film for enhanced preservation of perishable fruits'', Materials Today Chemistry 40 (2024) 102284. https://doi.org/10.1016/j.mtchem.2024.102284.

[21] M. Kula-Maximenko, A. Gorczyca, E. Pociecha, A. Gąstoł, J. Maciejewska-Prończuk & M. Oćwieja, ``Characterization of selected parameters of Chlorella vulgaris microalgae after short-term exposure to gold nanoparticles with different surface properties'', Journal of Environmental Chemical Engineering 10 (2022) 108248. https://doi.org/10.1016/j.jece.2022.108248.

[22] K. Wang, H. Liang, S. Pu, J. Li, C. Tan & S. Li, ``Antioxidant and catalytic reduction activity of green synthesized gold nanoparticles using water-soluble chitosan'', Journal of Macromolecular Science, Part A 62 (2025) 105. https://doi.org/10.1080/10601325.2024.2444431.

[23] Z. Villagrán, L. M. Anaya-Esparza, C. A. Velázquez-Carriles, J. M. Silva-Jara, J. M. Ruvalcaba-Gómez, E. F. Aurora-Vigo, E. Rodríguez-Lafitte, N. Rodríguez-Barajas, I. Balderas-León & F. Martínez-Esquivias, ``Plant-based extracts as reducing, capping, and stabilizing agents for the green synthesis of inorganic nanoparticles'', Resources 13 (2024) 70. https://doi.org/10.3390/resources13060070.

[24] N. N. Duy, D. X. Du, D. V. Phu, L. A. Quoc, B. D. Du & N. Q. Hien, ``Synthesis of gold nanoparticles with seed enlargement size by $gamma$-irradiation and investigation of antioxidant activity'', Colloids and Surfaces A: Physicochemical and Engineering Aspects 436 (2013) 633. https://doi.org/10.1016/j.colsurfa.2013.07.038.

[25] A. F. Abd Aziz & B. A. Suliasih, ``Morphology-dependent antioxidant activity of gold nanoparticles prepared using different electrolyte concentrations'', Chemistry and Materials 4 (2025) 9. https://doi.org/10.56425/cma.v4i1.93.

[26] C. Hano & B. H. Abbasi, ``Plant-Based Green Synthesis of Nanoparticles: Production, characterization and applications'', Biomolecules 12 (2021) 31. https://doi.org/10.3390/biom12010031.

[27] Z. Bahmanyar, F. Mohammadi, A. Gholami & M. Khoshneviszadeh, ``Effect of different physical factors on the synthesis of spherical gold nanoparticles towards cost-effective biomedical applications'', IET Nanobiotechnology 17 (2023) 1. https://doi.org/10.1049/nbt2.12100.

[28] M. Li, J. Wei, Y. Song & F. Chen, ``Gold nanocrystals: optical properties, fine-tuning of the shape, and biomedical applications'', RSC Advances 12 (2022) 23057. https://doi.org/10.1039/d2ra04242h.

[29] A. D. M. Owoyale, M. Galadimma, S. Y. Daniyan & N. Adabara, ``Quantitative phytochemical analysis and antifungal susceptibility of Vernonia amygdalina against some strains of Candida albicans'', Journal of Advances in Medical and Pharmaceutical Sciences 21 (2019) 1. https://doi.org/10.9734/jamps/2019/v21i330132.

[30] M. A. Hossain, N. K. Disha, J. H. Shourove & P. Dey, ``Determination of antioxidant activity and total tannin from drumstick (Moringa oleifera Lam.) leaves using different solvent extraction methods'', Turkish Journal of Agriculture--Food Science and Technology 8 (2020) 2749. https://doi.org/10.24925/turjaf.v8i12.2749-2755.4038.

[31] B. A. Soumana, A. I. Ibrahim, I. F. Ossamulu, M. M. Wun, H. S. Auta, H. L. Muhammad & H. A. Makun, ``Phytochemical analysis and antifungal activity of Parkia biglobosa and Eucalyptus camaldulensis (Steud.)'', African Journal of Biological Sciences 6 (2024) 10478. https://www.researchgate.net/profile/Muhammad-Wuna/publication/385172782_PHYTOCHEMICAL_ANALYSIS_AND_ANTIFUNGAL_ACTIVITY_OF_PARKIA_BIGLOBOSA_AND_EUCALYPTUS_CAMALDULENSIS_STEU/links/67194d5e2b65f6174dc3de4d/PHYTOCHEMICAL-ANALYSIS-AND-ANTIFUNGAL-ACTIVITY-OF-PARKIA-BIGLOBOSA-AND-EUCALYPTUS-CAMALDULENSIS-STEU.pdf.

[32] O. O. Stephen, O. J. Otorkpa, M. A. Emmanel, A. V. Amichi, A. Friday, A. P. Folorunsho, O. T. Tayo & O. C. Kehinde, ``Extracts of Telfairia occidentalis as an alternative treatment for Trypanosoma brucei infection in mice'', Tropical Journal of Drug Research 2 (2025) 70. https://doi.org/10.26538/tjdr/v2i3.2.

[33] F. Khan, M. Shariq, M. Asif, M. A. Siddiqui, P. Malan & F. Ahmad, ``Green nanotechnology: Plant-mediated nanoparticle synthesis and application'', Nanomaterials 12 (2022) 673. https://doi.org/10.3390/nano12040673.

[34] M. Oyaizu, ``Studies on products of browning reactions: antioxidative activities of product of browning reaction prepared from glucosamine'', Japan Journal of Nutrition 44 (1986) 307. https://doi.org/10.5264/eiyogakuzashi.44.307.

[35] G. Ruberto & M. T. Baratta, ``Antioxidant activity of selected essential oil components in two lipid model systems'', Food Chemistry, 69 (2000) 167. https://doi.org/10.1016/S0308-8146(99)00247-2.

[36] A. A. Anvar, H. Ahari & M. Ataee, ``Antimicrobial properties of food nanopackaging: A new focus on foodborne pathogens'', Frontiers in Microbiology 12 (2021) 690706. https://doi.org/10.3389/fmicb.2021.690706.

[37] D. G. García, C. Garzón-Romero, M. A. Salazar, K. J. Lagos, K. O. Campaña, A. Debut, K. Vizuete, M. R. Rivera, D. Niebieskikwiat, M. J. Benitez & M. P. Romero, ``Bioinspired synthesis of magnetic nanoparticles based on iron oxides using orange waste and their application as photo-activated antibacterial agents'', International Journal of Molecular Sciences 24 (2023) 4770. https://doi.org/10.3390/ijms24054770.

[38] F. U. Haider, U. Zulfiqar, N. ul Ain, S. Hussain, M. F. Maqsood, M. Ejaz, J. W. H. Yong & Y. Li, ``Harnessing plant extracts for eco-friendly synthesis of iron nanoparticle (Fe-NPs): Characterization and their potential applications for ameliorating environmental pollutants'', Ecotoxicology and Environmental Safety 281 (2024) 116620. https://doi.org/10.1016/j.ecoenv.2024.116620.

[39] M. Godoy-Gallardo, U. Eckhard, L. M. Delgado, Y. J. D. de Roo Puente, M. Hoyos-Nogués, F. J. Gil & R. A. Perez, ``Antibacterial approaches in tissue engineering using metal ions and nanoparticles: From mechanisms to applications'', Bioactive Materials 6 (2021) 4470. https://doi.org/10.1016/j.bioactmat.2021.04.033.

[40] C. C. Ilechukwu, C. O. Ezenwelu, J. C. Ifemeje, C. Okechukwu, J. N. Ilechukwu & I. H. Iheukwumere, ``In vitro antioxidant and phytochemical analysis of Solanum aethiopicum (Garden egg leaf) and Telfairia occidentalis (Fluted pumpkin leaf)'', IPS Interdisciplinary Journal of Biological Sciences 4 (2025) 107. https://doi.org/10.54117/iijbs.v4i3.56.

[41] A. O. Kalu, E. C. Egwim, A. A. Jigam & H. L. Muhammed, ``Green synthesis of magnetite nanoparticles using calotropis procera leaf extract and evaluation of its antimicrobial activity'', Nano Express 3 (2022) 045004. https://doi.org/10.1088/2632-959X/aca925.

[42] J. Ali, I. ur Rehman & J. A. Bangash, ``Phytochemicals content and in-vitro antioxidant properties of Azadirachta indica seeds, leaves and twigs prepared from different extraction techniques'', International Journal of Engineering, Science and Technology 14 (2023) 12. https://doi.org/10.4314/ijest.v14i4.2.

[43] T. Ahmad, M. Moniruzzaman, H. M. A. Asghar & et al., ``Mechanistic investigation of phytochemicals involved in green synthesis of gold nanoparticles using aqueous Elaeis guineensis leaves extract: Role of phenolic compounds and flavonoids'', Biotechnology and Applied Biochemistry 66 (2019) 698. https://doi.org/10.1002/bab.1787.

[44] T. H. P. Nguyen, T. P. Nguyen, T. A. T. Nguyen, T. D. Nguyen, S. W. Chang, D. D. Nguyen & D. D. La, ``Terminalia catappa leaf extract as a bio-reducing agent to synthesize Cu$_2$O nanoparticles for methylene blue photodegradation'', Discover Applied Sciences 6 (2024) 309. https://doi.org/10.1007/s42452-024-05990-3.

[45] S. Ghasemi, S. Dabirian, F. Kariminejad, D. E. Koohi, M. Nemattalab, S. Majidimoghadam, E. Zamani & F. Yousefbeyk, ``Process optimization for green synthesis of silver nanoparticles using Rubus discolor leaves extract and its biological activities against multi-drug resistant bacteria and cancer cells'', Scientific Reports 14 (2024) 4130. https://doi.org/10.1038/s41598-024-54702-9.

[46] X. Huang, S. Devi, M. Bordiga, C. S. Brennan & B. Xu, ``Phenolic compounds mediated biosynthesis of gold nanoparticles and evaluation of their bioactivities: A review'', International Journal of Food Science & Technology 58 (2023) 1673. https://doi.org/10.1111/ijfs.16346.

[47] S. N. Tanwar, Y. R. Parauha, Y. There, H. C. Swart & S. J. Dhoble, ``Plant-based biosynthesis of metal and metal oxide nanoparticles: An update on antimicrobial and anticancer activity'', ChemBioEng Reviews 11 (2024) e202400012. https://doi.org/10.1002/cben.202400012.

[48] J. O. Momoh, A. A. Manuwa, F. A. Ayinde & Y. O. Bankole, ``Nutritional, phytochemicals, gc-ms and antibacterial activities of aqueous red onion (allium cepa) extract against staphylococcus aureus and escherichia coli'', International Journal of Tropical Disease & Health 44 (2023) 35. https://doi.org/10.9734/ijtdh/2023/v44i51407.

[49] I. A. Baba, O. B. Awe, S. Mustapha, M. A. Abubakar, A. S. Abdulkareem, J. O. Tijani & K. S. Obayomi, ``Influence of plant-derived extracts on the synthesis, physicochemical properties, and applications of metal and metal oxide nanoparticles'', Hybrid Advances 13 (2026) 100666. https://doi.org/10.1016/j.hybadv.2026.100666.

[50] A. Alafnan, S. Sridharagatta, H. Saleem, U. Khurshid, A. Alamri, S. Y. Ansari, S. A. Zainal Abidin, S. A. Ansari, A. S. Alamri, N. Ahemad & S. Anwar, ``Evaluation of the phytochemical, antioxidant, enzyme inhibition, and wound healing potential of Calotropis gigantea (l.) dryand: A source of a bioactive medicinal product'', Frontiers in Pharmacology 12 (2021) 701369. https://doi.org/10.3389/fphar.2021.701369.

[51] J. Singh, T. Dutta, K. Home Kim, M. Rawat, P. Samddar & P. Kumar, ````Green'' synthesis of metals and their oxide nanoparticles: Applications for environmental remediation'', Journal of Nanobiotechnology 16 (2018) 84. https://doi.org/10.1186/s12951-018-0408-4.

[52] M. Aravind, M. Amalanathan & M. S. M. Mary, ``Synthesis of TiO$_2$ nanoparticles by chemical and green synthesis methods and their multifaceted properties'', SN Applied Sciences 3 (2021) 409. https://doi.org/10.1007/s42452-021-04281-5.

[53] M. Fahim, A. Shahzaib, N. Nishat, A. Jahan, T. A. Bhat & A. Inam, ``Green synthesis of silver nanoparticles: A comprehensive review of methods, influencing factors, and applications'', JCIS Open 16 (2024) 100125. https://doi.org/10.1016/j.jciso.2024.100125.

[54] A. M. Elbagory, C. N. Cupido, M. Meyer & A. A. Hussein, ``Large scale screening of southern African plant extracts for the green synthesis of gold nanoparticles using microtitre-plate method'', Molecules 21 (2016) 1498. https://doi.org/10.3390/molecules21111498.

[55] S. Basumatary, J. Daimari, A. Ghosh & A. K. Deka, ``Green synthesis of NPs (Ag & Au) from some plant families (Phyllanthaceae, Lamiaceae, Rutaceae and Euphorbiaceae) and their application in therapeutics: A review'', South African Journal of Botany 166 (2024) 624. https://doi.org/10.1016/j.sajb.2024.02.003.

[56] Y. Song, M. Sun, H. Wu, W. Zhao & Q. Wang, ``Temperature sensor based on surface plasmon resonance with TiO$_2$-Au-TiO$_2$ triple structure'', Materials 15 (2022) 7766. https://doi.org/10.3390/ma15217766.

[57] G.-Y. Kwak, Y. Han, S. Baik, B.-M. Kong, D.-C. Yang, S.-C. Kang & J. Sukweenadhi, ``Gold nanoparticles green-synthesized by the Suaeda japonica leaf extract and screening of anti-inflammatory activities on RAW 267.4 macrophages'', Coatings 12 (2022) 460. https://doi.org/10.3390/coatings12040460.

[58] Z. Zarei, H. Azarnivand, M. Moazeni, M. Bahmani, D. Razmjoue & F. Oroojalian, ``Salvia sclarea L. mediated green synthesis of gold nanoparticles (AuNPs) and evaluation of their antibacterial, anticandidal, and scolicidal properties'', Scientific Reports 15 (2025) 33392. https://doi.org/10.1038/s41598-025-18448-2.

[59] S. O. Aisida, K. Ugwu, A. C. Nwanya, A. K. H. Bashir, N. U. Nwankwo, I. Ahmed & F. I. Ezema, ``Biosynthesis of silver oxide nanoparticles using leave extract of Telfairia occidentalis and its antibacterial activity'', Materials Today: Proceedings 36 (2021) 208. https://doi.org/10.1016/j.matpr.2020.03.005.

[60] H. K. Talabi, J. Y. Talabi & M. Ayenuro, ``Green synthesis and characterization of silver nanoparticles using Telfairia occidentalis leaf extract and bactericide efficiency on epoxy matrix doped composites'', Journal of Biomimetics, Biomaterials and Biomedical Engineering 71 (2026) 33. https://doi.org/10.4028/p-4doGOW.

[61] F. Y. F. Taufeq, M. L. Nordin & H. Katas, ``Upscaling, toxicity and efficacy of multifaceted dressing embedded with dsirna-loaded gold nanoparticles for enhancing diabetic wound treatment'', PLoS ONE 20 (2025) e0327375. https://doi.org/10.1371/journal.pone.0327375.

[62] S. Ghosh, R. Ahmad, M. Zeyaullah & S. K. Khare, ``Microbial nano-factories: Synthesis and biomedical applications'', Frontiers in Chemistry 9 (2021) 626834. https://doi.org/10.3389/fchem.2021.626834.

[63] M. A. Alghuthaymi, C. Rajkuberan, T. Santhiya, O. Krejcar, K. Kuča, R. Periakaruppan & S. Prabukumar, ``Green synthesis of gold nanoparticles using Polianthes tuberosa L. floral extract'', Plants 10 (2021) 2370. https://doi.org/10.3390/plants10112370.

[64] Z. Nkentsha & S. Rambharose, ``Green-synthesized gold nanoparticles exhibit neuroprotective activity against oxidative stress-induced damage in SH-SY5Y cells'', Journal of Nanoparticle Research 27 (2025) 197. https://doi.org/10.1007/s11051-025-06387-y.

[65] S. Pasieczna-Patkowska, M. Cichy & J. Flieger, ``Application of fourier transform infrared (ftir) spectroscopy in characterization of green synthesized nanoparticles'', Molecules 30 (2025) 684. https://doi.org/10.3390/molecules30030684.

[66] R. C. Sandulovici, C.-M. Carmen-Marinela, A. Grigoroiu, C. A. Moldovan, M. Savin, V. Ordeanu, S. N. Voicu, D. Cord, G. M. Costache, M. L. Galatanu, M. Popescu, I. Sarbu, E. Mati, L. E. Ionescu, R. Neagu, V. Ţucureanu, R. M. Claudia, I. Mihalache, C. Romanitan & D. Dragomir, ``The physicochemical and antimicrobial properties of silver/gold nanoparticles obtained by `green synthesis' from willow bark and their formulations as potential innovative pharmaceutical substances'', Pharmaceuticals 16 (2023) 48. https://doi.org/10.3390/ph16010048.

[67] A. Cazacu, M. Dobromir, C. Chiruță & E.-L. Ursu, ``Chitosan-mediated environment-friendly synthesis of gold nanoparticles with enhanced photonic reactivity'', Nanomaterials 12 (2022) 4186. https://doi.org/10.3390/nano12234186.

[68] A. Fadaka, O. Aluko, S. Awawu & K. Theledi, ``Green synthesis of gold nanoparticles using Pimenta dioica leaves aqueous extract and their application as photocatalyst, antioxidant, and antibacterial agents'', Journal of Multidisciplinary Applied Natural Science 1 (2021) 78. https://doi.org/10.47352/jmans.v1i2.81.

[69] N. Kumar, A. Singh & V. Devra, ``Experimental investigation on plant extract-induced biosynthesis of Nickel nanoparticles'', Next Nanotechnology 7 (2025) 100104. https://doi.org/10.1016/j.nxnano.2024.100104.

[70] S. N. Shintre, S. Wadhai & P. Thakur, ``Synthesis of Ag/ZnO-AC composite photocatalyst: spectroscopic investigation, parameter optimization, synergistic effect and performance enhancement for cost-effective photocatalytic degradation of phenols and dyes'', Water Science and Technology 85 (2022) 2663. https://doi.org/10.2166/wst.2022.137.

[71] Z. Wang, T. Hu, R. Liang & M. Wei, ``Application of zero-dimensional nanomaterials in biosensing'', Frontiers in Chemistry 8 (2020) 320. https://doi.org/10.3389/fchem.2020.00320.

[72] J. O. Oladele, O. M. Oyeleke, O. O. Awosanya, B. D. Olowookere & O. T. Oladele, ``Fluted Pumpkin (Telfairia occidentalis) protects against phenyl hydrazine-induced anaemia and associated toxicities in rats'', Advances in Traditional Medicine 21 (2021) 739. https://doi.org/10.1007/s13596-020-00499-7.

[73] J. O. Oladele, M. O. Bamigboye, B. D. Olowookere, O. M. Oyeleke, J. C. Anyim, K. S. Oladele & I. O. Oyewole, ``Identification of bioactive chemical constituents presents in the aqueous extract of Telfairia Occidentalis and Its in vitro antioxidant activities'', Journal of Natural and Ayurvedic Medicine 4 (2020) 000237. https://doi.org/10.23880/jonam-16000237.

[74] W. C. Liao, C. S. Liao, Y.-C. Lin & C.-Y. Lien, ``Characterization of gold nanoparticles synthesized with Zingiber zerumbet extracts'', Journal of Chemistry 2024 (2024) 1358495. https://doi.org/10.1155/2024/1358495.

[75] A. Zuhrotun, D. J. Oktaviani & A. N. Hasanah, ``Biosynthesis of Gold and Silver nanoparticles using phytochemical compounds'', Molecules (Basel, Switzerland) 28 (2023) 3240. https://doi.org/10.3390/molecules28073240.

[76] A. Hidayat, A. Taufiq, Z. A. I. Supardi, S. M. Jayadininggar, U. Sa'adah, N. A. Astarini, T. Suprayogi & M. Diantoro, ``Synthesis and characterization of TiO$_2$/ZnO-Ag@TiO$_2$ nanocomposite and their performance as photoanode of organic dye-sensitized solar cell'', Materials Today: Proceedings 44 (2021) 3395. https://doi.org/10.1016/j.matpr.2020.11.862.

[77] G. Suriyakala, S. Sathiyaraj, R. Babujanarthanam, K. M. Alarjani, D. S. Hussein, R. A. Rasheed & K. Kanimozhi, ``Green synthesis of gold nanoparticles using Jatropha integerrima Jacq. flower extract and their antibacterial activity'', Journal of King Saud University-Science 34 (2022) 101830. https://doi.org/10.1016/j.jksus.2022.101830.

[78] S. A. Akintelu, B. Yao & A. S. Folorunso, ``Green synthesis, characterization, and antibacterial investigation of synthesized gold nanoparticles (AuNPs) from Garcinia kola pulp extract'', Plasmonics 16 (2021) 157. https://doi.org/10.1007/s11468-020-01274-9.

[79] M. N. Alam, S. Das, S. Batuta, D. Mandal & N. A. Begum, ``Green-nano chemistry for safe environment: bio-friendly synthesis of fluorescent monometallic (Ag and Au) and bimetallic (Ag/Au alloy) nanoparticles having pesticide sensing activity'', Journal of Nanostructure in Chemistry 6 (2016) 373. https://doi.org/10.1007/s40097-016-0209-y.

[80] A. Zulfiqar, M. Honkanen, Nonappa & M. Vippola, ``In Situ TEM imaging reveals the dynamic interplay between attraction, repulsion and sequential attraction-repulsion in gold nanoparticles'', Small (Weinheim an der Bergstrasse, Germany) 20 (2024) e2406943. https://doi.org/10.1002/smll.202406943.

[81] E. V. Abkhalimov & B. G. Ershov, ``Difference in the catalytic activity of atoms in the corners and at the edges of gold nanoparticles: hydrogen isotope exchange reaction'', International Journal of Molecular Sciences 25 (2024) 12022. https://doi.org/10.3390/ijms252212022.

[82] M. H. Ali, M. A. K. Azad, K. A. Khan, M. O. Rahman, U. Chakma & A. Kumer, ``Analysis of crystallographic structures and properties of silver nanoparticles synthesized using pkl extract and nanoscale characterization techniques'', ACS Omega 8 (2023) 28133. https://doi.org/10.1021/acsomega.3c01261.

[83] B. Roy & J. Das, ``Strengthening face centered cubic crystals by annealing induced nano-twins'', Scientific Reports 7 (2017) 17512. https://doi.org/10.1038/s41598-017-17848-3.

[84] H. Hassan, K. I. Omoniyi, F. G. Okibe, A. A. Nuhu & E. G. Echioba, ``Evaluation of antibacterial potential of biosynthesized plant leave extract mediated titanium oxide nanoparticles using Hypheae thiebeace and Anannos seneglensis'', Journal of Applied Sciences and Environmental Management 23 (2019) 1795. https://doi.org/10.4314/jasem.v23i10.5.

[85] M. Ahmad, I. Ahmad, E. Ahmed, M. S. Akhtar & N. R. Khalid, ``Facile and inexpensive synthesis of Ag doped ZnO/CNTs composite: Study on the efficient photocatalytic activity and photocatalytic mechanism'', Journal of Molecular Liquids 311 (2020) 113326. https://doi.org/10.1016/j.molliq.2020.113326.

[86] F. Z. Haque, R. Nandanwar & P. Singh, ``Evaluating photodegradation properties of anatase and rutile TiO$_2$ nanoparticles for organic compounds'', Optik 128 (2017) 191. https://doi.org/10.1016/j.ijleo.2016.10.025.

[87] M. Saunders, P. L. Clode, E. V. S. Wong, A.-L. Jessop, G. E. Shröder-Turk & F. de Tombeur, ``When biology meets materials science -- Interdisciplinary applications of electron microscopy'', Journal of Microscopy (2026) 1. https://doi.org/10.1111/jmi.70086.

[88] J. O. Tijani, O. Ugochukwu, L. A. Fadipe, M. T. Bankole, A. S. Abdulkareem & W. D. Roos, ``One-step green synthesis of WO 3 nanoparticles using Spondias mombin aqueous extract: effect of solution pH and calcination temperature'', Applied Physics A: Materials Science and Processing 125 (2019) 13. https://doi.org/10.1007/s00339-019-2450-y.

[89] V. Harish, M. M. Ansari, D. Tewari, M. Gaur, A. B. Yadav, M.-L. García-Betancourt, F. M. Abdel-Haleem, M. Bechelany & A. Barhoum, ``Nanoparticle and nanostructure synthesis and controlled growth methods'', Nanomaterials (Basel, Switzerland) 12 (2022) 3226. https://doi.org/10.3390/nano12183226.

[90] E. Mohseni, A. Rahmani, Z. Hamdi & P. Ghorbanzadeh, ``Efficiency of response surface method based on central composite design in optimizing the adsorption process of cadmium metal from aqueous solutions using activated charcoal prepared from walnut shell'', Desalination and Water Treatment 317 (2024) 100250. https://doi.org/10.1016/j.dwt.2024.100250.

[91] D. A. Said, A. M. Ali, M. M. Khayyat, M. Boustimi, M. Loulou & R. Seoudi, ``A study of the influence of plasmonic resonance of gold nanoparticle doped PEDOT : PSS on the performance of organic solar cells based on CuPc / C$_60$'', Heliyon 5 (2019) e02675. https://doi.org/10.1016/j.heliyon.2019.e02675.

[92] M. Iqbal, G. Usanase, K. Oulmi, F. Aberkane, T. Bendaikha, H. Fessi, N. Zine, G. Agusti, E. S. Errachid & A. Elaissari, ``Preparation of gold nanoparticles and determination of their particles size via different methods'', Materials Research Bulletin 79 (2016) 97. https://doi.org/10.1016/j.materresbull.2015.12.026.

[93] I. Hammami, N. M. Alabdallah, A. Al jomaa & M. kamoun, ``Gold nanoparticles: Synthesis properties and applications'', Journal of King Saud University - Science 33 (2021) 101560. https://doi.org/10.1016/j.jksus.2021.101560.

[94] J. S. Boruah, C. Devi, U. Hazarika, P. V. B. Reddy, D. Chowdhury, M. Barthakur & P. Kalita, ``Green synthesis of gold nanoparticles using an antiepileptic plant extract: in vitro biological and photo-catalytic activities'', RSC Advances 11 (2021) 28029. https://doi.org/10.1039/D1RA02669K.

[95] C. E. A. Botteon, L. B. Silva, G. V. Ccana-Ccapatinta, T. S. Silva, S. R. Ambrosio, R. C. S. Veneziani, J. K. Bastos & P. D. Marcato, ``Biosynthesis and characterization of gold nanoparticles using Brazilian red propolis and evaluation of its antimicrobial and anticancer activities'', Scientific Reports 11 (2021) 1974. https://doi.org/10.1038/s41598-021-81281-w.

[96] G. Suneetha, D. Ayodhya & P. Sunitha Manjari, ``Schiff base stabilized gold nanoparticles: Synthesis, characterization, catalytic reduction of nitroaromatic compounds, fluorometric sensing, and biological activities'', Results in Chemistry 5 (2023) 100688. https://doi.org/10.1016/j.rechem.2022.100688.

[97] S. B. Nadhe, S. A. Wadhwani, R. Singh & B. A. Chopade, ``Green synthesis of AuNPs by Acinetobacter sp. gwrva25: optimization, characterization, and its antioxidant activity'', Frontiers in Chemistry 8 (2020) 474. https://doi.org/10.3389/fchem.2020.00474.

[98] M. Alle, S. H. Lee & J. C. Kim, ``Ultrafast synthesis of gold nanoparticles on cellulose nanocrystals via microwave irradiation and their dyes-degradation catalytic activity'', Journal of Materials Science & Technology 41 (2020) 168. https://doi.org/10.1016/j.jmst.2019.11.003.

[99] P. S. Sadalage, R. V. Patil, D. V. Havaldar & et al., ``Optimally biosynthesized, PEGylated gold nanoparticles functionalized with quercetin and camptothecin enhance potential anti-inflammatory, anti-cancer and anti-angiogenic activities'', Journal of Nanobiotechnology 19 (2021) 84. https://doi.org/10.1186/s12951-021-00836-1.

[100] A. J. Love, V. V. Makarov, O. V. Sinitsyna, J. Shaw, I. V. Yaminsky, N. O. Kalinina & M. E. Taliansky, ``A genetically modified tobacco mosaic virus that can produce gold nanoparticles from a metal salt precursor'', Frontiers in Plant Science 6 (2015) 984. https://doi.org/10.3389/fpls.2015.00984.

[101] P. Parajuli, R. Mendoza-Cruz, U. Santiago, A. Ponce & M. J. Yacamán, ``The evolution of growth, crystal orientation, and grain boundaries disorientation distribution in gold thin films'', Crystal Research and Technology 53 (2018) 1800038. https://doi.org/10.1002/crat.201800038.

[102] Z. Jelen, M. Krajewski, F. Zupanič, P. Majerič, T. Švarc, I. Anžel, J. Ekar, S.-C. Liou, J. Kubacki, M. Tokarczyk & R. Rudolf, ``Melting point of dried gold nanoparticles prepared with ultrasonic spray pyrolysis and lyophilisation'', Nanotechnology Reviews 12 (2023) 20220568. https://doi.org/10.1515/ntrev-2022-0568.

[103] V. Lotito & T. Zambelli, ``Pattern detection in colloidal assembly: A mosaic of analysis techniques'', Advances in Colloid and Interface Science 284 (2020) 102252. https://doi.org/10.1016/j.cis.2020.102252.

[104] T. Donnelly, G. O'Connell & J. G. Lunney, ``Metal nanoparticle film deposition by femtosecond laser ablation at atmospheric pressure'', Nanomaterials (Basel, Switzerland) 10 (2020) 2118. https://doi.org/10.3390/nano10112118.

[105] H. M. Saleh, O. A. Soliman, M. O. Elshazly, A. Raafat, A. K. Gohar & T. A. Salaheldin, ``Acute hematologic, hepatologic, and nephrologic changes after intraperitoneal injections of 18 nm gold nanoparticles in hamsters'', International Journal of Nanomedicine 11 (2016) 2505. https://doi.org/10.2147/IJN.S102919.

[106] Y. V. Ryabchikov, ``Design of `green' plasmonic nanocomposites with multi-band blue emission for ultrafast laser hyperthermia'', Nanoscale 16 (2024) 19453. https://doi.org/10.1039/D4NR03120B.

[107] S. Akhtar, F. Zuhair, M. Nawaz & F. A. Khan, ``Green synthesis, characterization, morphological diversity, and colorectal cancer cytotoxicity of gold nanoparticles'', RSC Advances 14 (2024) 36576. https://doi.org/10.1039/D4RA06340F.

[108] M. Jalal, M. A. Ansari, M. Alshamrani, S. G. Ali, Y. F. Jamous, S. A. Alyahya, M. S. Alhumaidi, K. A. Altammar, A. Alsalhi, H. M. Khan & M. N. Alomary, ``Crinum latifolium mediated biosynthesis of gold nanoparticles and their anticandidal, antibiofilm and antivirulence activity'', Journal of Saudi Chemical Society 27 (2023) 101644. https://doi.org/10.1016/j.jscs.2023.101644.

[109] H. Kalantari & R. J. Turner, ``Structural and antimicrobial properties of synthesized gold nanoparticles using biological and chemical approaches'', Frontiers in Chemistry 12 (2024) 1482102. https://doi.org/10.3389/fchem.2024.1482102.

[110] Y. Han, X. Zhang, L. Zhu, K. Wang, D. Sha, N. Ji, J. Fan, Q. Chen, K. Chen, Y. Zhou, X. Yao, B. Li & L. Guan, ``Modulation of LPS-induced RAW 264.7 macrophages by Pulsatilla koreana-synthesized gold nanoparticles'', Frontiers in Nutrition 12 (2025) 1666919. https://doi.org/10.3389/fnut.2025.1666919.

[111] M. Z. Lafta, R. R. H. Al-Samarrai & M. Bouaziz, ``Green synthesis of silver and gold nanoparticles using quercetin extracted from Arctium lappa by HPLC, characterization and estimation of antioxidant activity'', Results in Chemistry 13 (2025) 102028. https://doi.org/10.1016/j.rechem.2025.102028.

[112] S. Rokkarukala, T. Cherian, C. Ragavendran, R. Mohanraju, C. Kamaraj, Y. Almoshari, A. Albariqi, M. H. Sultan, A. Alsalhi & S. Mohan, ``One-pot green synthesis of gold nanoparticles using Sarcophyton crassocaule, a marine soft coral: Assessing biological potentialities of antibacterial, antioxidant, anti-diabetic and catalytic degradation of toxic organic pollutants'', Heliyon 9 (2023) e14668. https://doi.org/10.1016/j.heliyon.2023.e14668.

[113] S. Ahmad, S. Ahmad, Q. Xu, I. Khan, X. Cao, R. Yang & H. Yan, ``Green synthesis of gold and silver nanoparticles using crude extract of Aconitum violaceum and evaluation of their antibacterial, antioxidant and photocatalytic activities'', Frontiers in Bioengineering and Biotechnology 11 (2024) 1320739. https://doi.org/10.3389/fbioe.2023.1320739.

[114] K. Phukan, R. Devi & D. Chowdhury, ``Green synthesis of gold nano-bioconjugates from onion peel extract and evaluation of their antioxidant, anti-inflammatory, and cytotoxic studies'', ACS Omega 6 (2021) 17811. https://doi.org/10.1021/acsomega.1c00861.

[115] J. K. Patra, Y. Kwon & K.-H. Baek, ``Green biosynthesis of gold nanoparticles by onion peel extract: Synthesis, characterization and biological activities'', Advanced Powder Technology 27 (2016) 2204. https://doi.org/10.1016/j.apt.2016.08.005.

[116] C. Carnovale, G. Bryant, R. Shukla & V. Bansal, ``Identifying trends in gold nanoparticle toxicity and uptake: size, shape, capping ligand, and biological corona'', ACS Omega 4 (2019) 242. https://doi.org/10.1021/acsomega.8b03227.

[117] J. Flieger, W. Flieger, J. Baj & R. Maciejewski, ``Antioxidants: Classification, natural sources, activity/capacity measurements, and usefulness for the synthesis of nanoparticles'', Materials 14 (2021) 4135. https://doi.org/10.3390/ma14154135.

[118] A. S. El Newehy, S. F. Gheda, M. M. Ismail, D. Aldisi, M. M. A. Abulmeaty & M. E. Elshobary, ``Fucoidan-based gold nanoparticles: Antioxidant and anticancer potential from Turbinaria decurrens and Sargassum cinereum'', Pharmaceutics 17 (2025) 826. https://doi.org/10.3390/pharmaceutics17070826.

[119] F. Fragou, A. Theofanous, Y. Deligiannakis & M. Louloudi, ``Nanoantioxidant materials: Nanoengineering inspired by nature'', Micromachines 14 (2023) 383. https://doi.org/10.3390/mi14020383.

[120] O. K. Awote, A. B. Ojekale, M. I. Kazeem, A. G. Adeyemo, J. O. Igbalaye, R. Ilesanmi, O. B. Kanmodi, H. D. Azeez, H. T. Ramoni & D. S. Salako, ``Antidiabetic, antioxidant, antiglycation and anti-inflammatory potentials of green-synthesized silver nanoparticles using Telfairia occidentalis leaf and stem aqueous extracts'', Letters in Applied NanoBioScience 13 (2024) 41. https://doi.org/10.33263/LIANBS131.041.

[121] A. Karnwal, R. S. Kumar Sachan, I. Devgon, J. Devgon, G. Pant, M. Panchpuri, A. Ahmad, M. B. Alshammari, K. Hossain & G. Kumar, ``Gold nanoparticles in nanobiotechnology: from synthesis to biosensing applications'', ACS Omega 9 (2024) 29966. https://doi.org/10.1021/acsomega.3c10352.

[122] F. Ruth, W. Soeratri, D. M. Hariyadi, E. Septiana, S. E. Muttaqien, A. W. Munfadlila, F. C. Sekaringtyas & A. Rosyidah, ``Gold nanoparticle synthesized from centella asiatica: emphasis on optimization, characterization, antioxidant, antiglycation, and cytotoxicity effect as an anti-aging cosmetic ingredient'', BioNanoScience 15 (2025) 45. https://doi.org/10.1007/s12668-024-01713-5.

[123] Y. Bo, Y. Wang, Y. Liu, J. Liu, H. Shen & S. Wang, ``Green synthesis of gold nanoparticles by celastrol for chemotherapy and photothermal anticancer therapy'', Materials Open 02 (2024) 2450005. https://doi.org/10.1142/S2811086224500055.