Figure 5: Capture and release of nanoparticles.

TEM images of stomatocytes filled with platinum nanoparticles (a) before and (b) after exposure to a magnetic field of 20 T and back to 0 T (40 mT s⁻¹); note the release of the platinum nanoparticles in the medium (marked with yellow arrows). (c) Dynamic light-scattering measurements of stomatocytes entrapping platinum nanoparticles before and after deformation in a magnetic field; the release of platinum nanoparticles during the deformation into the wide-opening prolate morphology is shown. (d,e) TEM images of the stomatocytes entrapping 40-nm platinum nanoparticles at different magnifications. The scale bar for the TEM images is 200 nm. (f) Size of the opening of the stomatocytes at 0, 10 and 20 T and their TEM images demonstrating the gradual opening and development of shape asymmetry of the objects during the process. (g) Cryo-TEM images of stomatocytes entrapping 60-nm platinum nanoparticles at different angles demonstrating the presence of the particles inside of the structures. The scale bar for the cryo-TEM images is 100 nm. (h) Asymmetric field flow fractionation chromatogram of the 60-nm platinum nanoparticles used in the capture experiment, stomatocytes after capture of particles in the magnetic field and after their purification via spin filtering to remove the free platinum nanoparticles. Note the chromatogram after spin filtering shows complete removal of free PtNP. The samples were then used for quantification of the amount of platinum inside of the structures via ICP-MS showing the presence of 2.43±0.11 mg of Platinum per 10 mg polymer (1 ml).