Medusa particles are single crystal magnetite nanoparticles with polycaprolactone-<i>b</i>-poly(ethylene glycol) diblock (PCL-b-PEG) copolymer brushes covalently linked to the particle surface by a silane coupling agent. In aqueous media the hydrophobic PCL block collapsed around the magnetite particle, forming a 1 to 2 nm thick, semi-crystalline shell. The hydrophilic PEG block formed a corona around the particle, allowing dispersion in water. Doxorubicin, a cancer drug, was trapped in the PCL shell. Isothermal release studies showed the doxorubicin was slowly released at 279 and 300 K, while the release rate more than doubled above 310 K. Doxorubicin was electrochemically active in PBS buffer, allowing electrochemical detection and quantification of free doxorubicin. Application of a 430 kHz, 280 G amplitude ac magnetic field heated the magnetite particles, which melted the PCL shell, releasing the doxorubicin.

Magnetically stimulated release from Medusa particles

253rd National Meeting (2017)

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