Are reported methods for synthesizing nanoparticles and microparticles by magnetic stirrer reproducible?

Document Type: Hypothesis


1 Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran

2 Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran

3 Pediatric Urology and Regenerative Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran

4 Department of Tissue Engineering, School of Advanced Technologies in Medicine, Mazandaran University of Medical Sciences, Sari, Iran

5 Cellular and Molecular Research Center, School of Medicine, Yasuj University of Medical Sciences, Yasuj, Iran

6 Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran



One of the most common tools for fabricating different drug-loaded polymeric particles is magnetic stirrer, a widely-used tool in nano-based drug delivery systems. Typically, the revolutions per minute (rpm) or G-Force of the stirrer are reported in related literature, while other parameters generate less attention and must be better understood. Reporting the rpm or G-Force is likely insufficient for producing the same vortex flow intensity and mono-dispersity as having a reliable and reproducible nanoparticle and microparticle synthesis method. We speculate that the magnetic stirrer bar’s length and diameter, and the size of the cylindrical container, affect the qualities of nanoparticles and microparticles. Given the importance of these particle characteristics in the field of nanomedicine, understanding these details would improve reporting method reliability. These data are currently missing in most related papers and must be reported. The purpose of our study is to highlight the importance of these underestimated parameters (magnetic bar’s length, diameter, and the size of the cylindrical container) and the impact on the reproducibility of particle synthesis methods using a magnetic stirrer.


1. Patra, J.K., et al., Nano based drug delivery systems: recent developments and future prospects. Journal of nanobiotechnology, 2018. 16(1): p. 71.
2. Dang, Y. and J. Guan, Nanoparticle-based Drug Delivery Systems for Cancer Therapy. Smart Materials in Medicine, 2020.
3. Ben-Akiva, E., et al., Polymeric micro-and nanoparticles for immune modulation. Biomaterials science, 2019. 7(1): p. 14-30.
4. Dacoba, T.G., et al. Modulating the immune system through nanotechnology. in Seminars in immunology. 2017. Elsevier.
5. Rezvantalab, S., et al., PLGA-based nanoparticles in cancer treatment. Frontiers in pharmacology, 2018. 9: p. 1260.
6. Kızılbey, K., Optimization of rutin-loaded PLGA nanoparticles synthesized by single-emulsion solvent evaporation method. Acs Omega, 2019. 4(1): p. 555-562.
7. Chenthamara, D., et al., Therapeutic efficacy of nanoparticles and routes of administration. Biomaterials Research, 2019. 23(1): p. 1-29.
8. Onoue, S., S. Yamada, and H.-K. Chan, Nanodrugs: pharmacokinetics and safety. International Journal of Nanomedicine, 2014. 9: p. 1025.
9. Hernández-Giottonini, K.Y., et al., PLGA nanoparticle preparations by emulsification and nanoprecipitation techniques: effects of formulation parameters. RSC Advances, 2020. 10(8): p. 4218-4231.
10. Hawari, A., C. Tham, and Z.A.A. Hamid. Effect of Synthesis Parameters on Size of the Biodegradable Poly (L-Lactide)(PLLA) Microspheres. in Advanced Materials Research. 2014. Trans Tech Publ.
11. Jyothi, N.V.N., et al., Microencapsulation techniques, factors influencing encapsulation efficiency. Journal of microencapsulation, 2010. 27(3): p. 187-197.
12. Aravand, M.A. and M.A. Semsarzadeh. Particle formation by emulsion inversion method: effect of the stirring speed on inversion and formation of spherical particles. in Macromolecular symposia. 2008. Wiley Online Library.
13. Halász, G., et al., Vortex flow generated by a magnetic stirrer. American Journal of Physics, 2007. 75(12): p. 1092-1098.
14. McCall, R.L. and R.W. Sirianni, PLGA nanoparticles formed by single-or double-emulsion with vitamin E-TPGS. JoVE (Journal of Visualized Experiments), 2013(82): p. e51015.
15. Bile, J., et al., The parameters influencing the morphology of poly (ɛ-caprolactone) microspheres and the resulting release of encapsulated drugs. International journal of pharmaceutics, 2015. 494(1): p. 152-166.
16. Li, D. and R.B. Kaner, Shape and aggregation control of nanoparticles: not shaken, not stirred. Journal of the American Chemical Society, 2006. 128(3): p. 968-975.

Volume 51, Issue 2
December 2020
Pages 498-500
  • Receive Date: 25 June 2020
  • Revise Date: 06 August 2020
  • Accept Date: 02 September 2020