Magnetic cell separation using nano-sized bacterial magnetic particles with reconstructed magnetosome membrane

Tomoko Yoshino, Hisashi Hirabe, Masayuki Takahashi, Motoki Kuhara, Haruko Takeyama, Tadashi Matsunaga*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

79 Citations (Scopus)


Magnetic nanoparticles produced by magnetotactic bacterium, bacterial magnetic particles (BacMPs), covered with a lipid bilayer membrane (magnetosome membrane) can be used to separate specific target cells from heterogeneous mixtures because they are easily manipulated by magnets and it is easy to display functional proteins on their surface via genetic engineering. Despite possessing unique and valuable characteristics, the potential toxicity of BacMPs to the separated cells has not been characterized in detail. Here, a novel technique was developed for the reconstruction of magnetosome membrane of BacMPs expressing protein A (protein A-BacMPs) to reduce cytotoxicity and the newly developed nanomaterial was then used for magnetic cell separation. The development of the magnetosome membrane-reconstructed protein A-BacMP was based on the characteristics of the Mms13 anchor protein, which strongly binds to the magnetite surface of BacMPs. Treatment of protein A-BacMPs with detergents removed contaminating proteins but did not affect retention of Mms13-protein A fusion proteins. The particle surfaces were then reconstructed with phosphatidylcholine. The protein A-BacMPs containing reconstructed magnetosome membranes remained dispersible and retained the ability to immobilize antibody. In addition, they contained few membrane surface proteins and endotoxins, which were observed on non-treated protein A-BacMPs. Magnetic separation of monocytes and B-rymphocytes from the peripheral blood was achieved with high purity using magnetosome membrane-reconstructed protein A-BacMPs.

Original languageEnglish
Pages (from-to)470-477
Number of pages8
JournalBiotechnology and bioengineering
Issue number3
Publication statusPublished - 2008 Oct 15
Externally publishedYes


  • Cell separation
  • Magnetic nanoparticle
  • Membrane
  • Phospholipid

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology


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