Syringe-Injectable, Self-Expandable, and Ultraconformable Magnetic Ultrathin Films

Kento Yamagishi, Akihiro Nojiri, Eiji Iwase, Michinao Hashimoto*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Syringe-injectable biomaterials and medical devices are important as minimally invasive implants for diagnosis, therapy, and regenerative medicine. Free-standing polymeric nanosheets with a thickness less than 1 μm and a flexural rigidity less than 10-2 nN m are a promising platform of syringe-injectable, implantable devices that provide conformable and long-term stable adhesion to the target biological tissues for in situ delivery of therapeutic materials. Here, we developed free-standing ultrathin films (<1 μm thick) based on polyurethane-based shape-memory polymer (SMP) and magnetic nanoparticles (MNP), termed MNP-SMP nanosheets. With the temperature-mediated shape-memory effect of SMP, we overcome the limitation in the manipulation of the conventional polymer nanosheets. In particular, we demonstrated the following four capabilities using the 710 nm thick MNP-SMP nanosheet with the glass transition temperature (Tg) of 25 °C: (1) syringe-injectability through the medical needles, (2) self-expandability after ejection, (3) conformability and removability on the biological surfaces, and (4) guidability in an external magnetic field. The MNP-SMP nanosheets were readily interfaced with an additional layer of poly(lactic-co-glycolic acid) (PLGA) to extend their functionality as a carrier of molecular and cellular drugs. The MNP-SMP nanosheets will contribute to the development of advanced syringe-injectable medical devices as a platform to deliver drugs, sensors, cells, and engineered tissues to the specific site or lesion in the body for minimally invasive diagnosis and therapy.

Original languageEnglish
Pages (from-to)41770-41779
Number of pages10
JournalACS Applied Materials and Interfaces
Issue number44
Publication statusPublished - 2019 Nov 6


  • magnetic nanoparticles
  • polymer nanosheets
  • self-expandable devices
  • shape-memory polymers
  • syringe-injectable devices

ASJC Scopus subject areas

  • Materials Science(all)


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