Impact of microwave synthesis time on the shape of silver nanostructures and their antibacterial activity


  • Nhat Hieu HOANG Quy Nhon University, 170 An Duong Vuong, Quy Nhon City, Binh Dinh Province, 820000, Vietnam
  • Van Nghia NGUYEN Quy Nhon University, 170 An Duong Vuong, Quy Nhon City, Binh Dinh Province, 820000, Vietnam
  • Thi Tho NGUYEN Quy Nhon University, 170 An Duong Vuong, Quy Nhon City, Binh Dinh Province, 820000, Vietnam
  • Thi Mong Diep NGUYEN Quy Nhon University, 170 An Duong Vuong, Quy Nhon City, Binh Dinh Province, 820000, Vietnam



Nanotechnology, silver nanoparticles, nanowires, nanosphere, nanoparticles


Silver is a well-known effective antibacterial and disinfectant material with relatively few side effects. Nanosilver derived from it, have strong antibacterial, antifungal and broad-spectrum antiviral properties. This study describes how the microwave synthesis durations of silver nanoparticles affect their shape, and the effect of the shapes of these nanoparticles on their antibacterial activity. The optical properties of the nanosilver were examined through UV-Vis absorption spectroscopy. The morphology of the grain was determined by transmission electron microscopy (TEM), and the crystallinity of the nanosilver was confirmed by X-ray diffraction (XRD). The antibacterial activities were assessed using bacterial pathogens Bacillus cereus and Bacillus megaterium, and were performed using the disk diffusion method. The obtained results show that (i) the shape and size of the nanosilver change when the microwave time is increased. They are of various sizes but almost all circular in shape when microwaved for 1.5 min, of larger sizes and different non-spherical geometric shapes after 3 min of microwave, and converted to nanowires after 5 min of microwave. (ii) Bacillus cereus and Bacillus megaterium were sensitive to all nanosilver but the antibacterial activity was more potent when the nanosilver possessed a defined shape than when they were silver nanowires.


Download data is not yet available.


M. Ehling-Schulz, D. Lereclus, and T. M. Koehler, “The bacillus cereus group: bacillus species with pathogenic potential,” Microbiol Spectrum, vol. 7, no. 3, pp. 1-60, 2019.

M. F. Abdel-Monaim, M. R. Gabr, S. M. El-Gantiry, M. N. Shaat, and A. A. El-Bana, “Bacillus megaterium, a new pathogen on lupine plants in Egypt,” Journal of Bacteriology Research, vol. 4, no. 2, pp. 24-32, 2012.

M. Saravanan, S. K. Barik, D. MubarakAli, P. Prakash, and A. Pugazhendhi, “Synthesis of silver nanoparticles from Bacillus brevis (NCIM 2533) and their antibacterial activity against pathogenic bacteria,” Microbial Pathogenesis, vol. 116, pp. 221-226, 2018.

D. Rai, N. L. Pham, J. T. Harty, and V. P. Badovinac, “Tracking the total CD8 T cell response to infection reveals substantial discordance in magnitude and kinetics between inbred and outbred hosts,” The Journal of Immunology, vol. 183, no. 12, pp. 7672-7681, 2009.

X. F. Zhang, W. Shen, and S. Gurunathan, “Silver nanoparticle-mediated cellular responses in various cell lines: an in vitro model,” International Journal of Molecular, vol. 17, no. 10, pp. 1603, 2016.

S. Gurunathan, J. Han, J. H. Park, and J. H. Kim, “A green chemistry approach for synthesizing biocompatible gold nanoparticles,” Nanoscale Research Letters, vol. 9, no. 1, pp. 248, 2014.

J. Xu, Y. Li, H. Wang, M. Zhu, W. Feng, and G. Liang, “Enhanced antibacterial and anti-biofilm activities of antimicrobial peptides modified silver nanoparticles,” International Journal of Nano-medicine, vol. 16, pp. 4831-4846, 2021.

S. Khorrami, A. Zarrabi, M. Khaleghi, M. Danaei, and M. R. Mozafari, “Selective cytotoxicity of green synthesized silver nanoparticles against the MCF-7 tumor cell line and their enhanced antioxidant and antimicrobial properties,” International Journal of Nanomedicine, vol. 13, pp. 8013-8024, 2018.

V. S. Ramkumar, A. Pugazhendhi, K. Gopalakrishnan, P. Sivagurunathan, G. D. Saratale, T. N. B. Dung, and E. Kannapiran, “Biofabrication and characterization of silver nanoparticles using aqueous extract of seaweed Enteromorpha compressa and its biomedical properties,” Biotechnology Reports, vol. 14, pp. 1-7, 2017.

N. Duran, G. Nakazato, and A. B. Seabra, “Antimicrobial activity of biogenic silver nanoparticles, and silver chloride nano-particles: an overview and comments,” Applied Microbiology and Biotechnology, vol. 100, no. 15, pp. 6555-6570, 2016.

R. Shanmuganathan, D. MubarakAli, D. Prabakar, H. Muthukumar, N. Thajuddin, S. S. Kumar, and A. Pugazhendhi, “An enhancement of antimicrobial efficacy of biogenic and ceftriaxone-conjugated silver nanoparticles: green approach,” Environmental science and pollution research international, vol. 25, no. 11, pp. 10362-10370, 2018.

J. M. Jacob, M. S. John, A. Jacob, P. Abitha, S. S. Kumar, R. Rajan, N. Suganthy, and P. Arivalagan, “Bactericidal coating of paper towels via sustainable biosynthesis of silver nanoparticles using ocimum sanctum leaf extract,” Materials Research Express, vol. 6, no. 4, p. 045401, 2019.

I. Pastoriza-Santos, and L. M. Liz-Marzán, Formation of PVP-protected metal nanoparticles in DMF,” Langmuir, vol. 18, no. 7, pp. 2888-2894, 2002.

C. M. Gonzalez, Y. Liu, and J. C. Scaiano, “Photochemical strategies for the facile synthesis of gold-silver alloy and core-shell bimetallic nanoparticles,” Journal of Physical Chemistry C, vol. 113, no. 27, pp. 11861-11867. 2009.

B. Yin, H. Ma, S. Wang, and S. Chen, “Electrochemical synthesis of silver nanoparticles under protection of poly(N-vinylpyrrolidone),” Journal of Physical Chemistry B, vol. 107, no. 34, pp. 8898-8904, 2003.

S. S. Shankar, A. Ahmad, and M. Sastry, “Geranium leaf assisted biosynthesis of silver nanoparticles,” Biotechnology Progress, vol. 19, pp. 1627-1631, 2003.

P. Mukherjee, M. Roy, B. P. Mandal, G. K. Dey, P. K. Mukherjee, J. Ghatak, A. K. Tyagi, and S. P. Kale, “Green synthesis of highly stabilized nanocrystalline silver particles by a non-pathogenic and agriculturally important fungus T. asperellum,” Nanotechnology, vol. 19, no. 7, p. 075103, 2008.

D. MubarakAli, N. Thajuddin, K. Jeganathan, and M. Gunasekaran, “Plant extract mediated synthesis of silver and gold nanoparticles and its antibacterial activity against clinically isolated pathogens,” Colloids Surf B Biointerfaces, vol. 85, pp. 360-365, 2011.

M. Thirunavoukkarasu, U. Balaji, S. Behera, P. K. Panda, and B. K. Mishra, “Biosynthesis of silver nanoparticle from leaf extract of Desmodium gangeticum (L.) DC. and its biomedical potential,” Spectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy, vol. 116, pp. 424-427, 2013.

V. N. Anjana, M. Joseph, S. Francis, A. Joseph, E. P. Koshy, and B. Mathew, “Microwave assisted green synthesis of silver nanoparticles for optical, catalytic, biological and electrochemical applications,” Artif Cells Nanomed Biotechnol, vol. 49, no. 1, pp. 438-449, 2021.

M. N. Nadagouda, T. F. Speth, and R. S. Varma, “Microwave-assisted green synthesis of silver nanostructures,” Accounts of Chemical Research, vol. 44, no. 7, pp. 469-478, 2011.

S. N. Nyamu, L. Ombaka, E. Masika, and M. Ng'ang'a, “One-pot microwave-assisted synthesis of size-dependent l-glutathione-capped spherical silver nanoparticles suitable for materials with antibacterial properties,” Journal of Interdisciplinary Nanomedicine, vol. 4, no. 3, pp 86-94, 2019.

D. S. Chung, H. Kim, J. Ko, J. Lee, B. Hwang, S. Chang, B. Kim, and S.-J. Chung, “Microwave synthesis of silver nano-particles using different pentose carbohydrates as reducing agents,” Journal of Chemistry and Chemical Engineering, vol. 12, pp. 1-10, 2018.

H. Liang, W. Wang, Y. Huang, S. Zhang, H. Wei, and H. Xu, “Controlled synthesis of uniform silver nanospheres,” The Journal of Physical Chemistry C, vol. 114, pp. 7427-7431, 2010.

L. Bachenheimer, R. Scherzer, P. Elliott, S. Stagon, L. Gasparov, and H. Huang, “Degradation mechanism of ag nanorods for surface enhanced raman spectroscopy,” Scientific Reports, vol. 7, pp. 4-7, 2017.

H. N. Hieu, D. T. H. Trang, V. T. T. Hien, N. V. Nghia, N. T. Lam, and T. M. D. Nguyen, “Microorganism-mediated green synthesis of silver nanoparticles using Aspergillus niger and Bacillus megaterium,” Digest Journal of Nanomaterials and Biostructures, vol. 17, no. 1, pp. 359-367, 2022.

S. Link, and M. A. El-Sayed, “Optical properties and ultrafast dynamics of metallic nanocrystals,” Annual Review of Physical Chemistry, vol. 54, pp. 331-366, 2003.

H. M. Abd-Elnaby, G. M. Abo-Elala, U. M. Abdel-Raouf, and M. M. Hamed, “Antibacterial and anticancer activity of extracellular synthesized silver nanoparticles from marine Streptomyces rochei MHM13,” Egyptian Journal of Aquatic Research, vol. 42, pp. 301-312, 2016.

S. Joseph, and B. Mathew, “microwave assisted biosynthesis of silver nanoparticles using the rhizome extract of alpinia galanga and evaluation of their catalytic and antimicrobial activities,” Journal of Nanoparticles, vol. 2014, ID 967802, 2014.

M. Tsuji, Y. Nishizawa, K. Matsumoto, N. Miyamae, T. Tsuji, and M. Kubokawa, “Effects of chain length of polyvinyl-pyrrolidone for the synthesis of silver nanostructures by a microwave-polyol method,” Materials Letters, vol 60, pp. 834-838, 2006.

N. V. Nghia, N. N. K. Truong, N. M. Thong, and N. P. Hung, “Synthesis of nanowire-shaped silver by polyol process of

sodium chloride,” International Journal of Materials and Chemistry, vol. 2, no. 2, pp 75-78, 2012.

X. L. Tang, M. Tsuji, M. Nishio, and P. Jiang, “Roles of chloride anions in the shape evolution of anisotropic silver nano-structures in poly(vinylpyrrolidone) (PVP)-assisted polyol process,” Bulletin of the Chemical Society of Japan, vol. 82, no. 10, pp. 1304-1312, 2009.

I. Sondi, and B. Salopek-Sondi, “Silver nanoparticles as anti- microbial agent: a case study on E. coli as a model for Gram-negative bacteria,” Journal of Colloid and Interface Science, vol. 275, pp. 177-182, 2004.

M. Sathishkumar, K. Sneha, S. W. Won, C. W. Cho, S. Kim, and Y. S. Yun, “Cinnamon zeylanicum bark extract and powder mediated green synthesis of nano-crystalline silver particles and its bactericidal activity,” Colloids Surf B Biointerfaces, vol. 73, pp. 332-338, 2009.




How to Cite

N. H. . HOANG, V. N. . NGUYEN, T. T. . NGUYEN, and T. M. D. . NGUYEN, “Impact of microwave synthesis time on the shape of silver nanostructures and their antibacterial activity”, J Met Mater Miner, vol. 33, no. 1, pp. 101–106, Mar. 2023.



Original Research Articles