N‐isopropylacrylamide (NIPAM) and acrylic acid (AA) copolymer microgels P(NIPAM ‐co‐AA) with different amount of AA were prepared by using a reverse suspension polymerization technique. The polymeric microgels were used firstly as micro‐containers to include Fe3O4 nanoparticles and then as micro‐reactors to control the hydrolysis of tetraethyl orthosilicate (TEOS). In this way, various super‐paramagnetic composite microspheres (P(NIPAM‐AA)/Fe3O4/SiO2) with different morphologies were prepared. It was demonstrated that the morphologies of the composite microspheres could be tailored to a certain extent by either varying the ratio of the two monomer units in the template microgels or the amount of SiO2 deposited. The sensitivity of the composite microspheres to an external magnetic field was determined by the amount of Fe3O4 included. The magnetic responsibility of the composite microspheres, and the ease of modifying the surfaces may make the microspheres of important use in the mild separation of bioactive materials, loading of active materials, and radiation and shock absorption, etc.

Vibration caused by ultrasonic waves can change the structure of cell membrane and enhance its permeation. In the last decade, a new ultrasound-aided method, sonoporation, has been proposed and utilized to transmit target molecules (such as drugs and DNA) into cells for therapy. The objective of this study was to investigate the method of loading nanometer-sized superparamagnetic iron oxide particles into Sarcoma 180 cells by sonoporation without chemical agents. The SPIO nanoparticles were prepared in our laboratory by means of classical coprecipitation and the formation of Fe3O4 crystal in SPIO nanoparticles was confirmed by x-ray diffraction analysis with its other characteristics assessed by magnetic hysteresis loops and size distribution. Cell labeling with SPIOs using sonoporation was successfully demonstrated in vitro for sarcoma180 cell suspensions from ICR mice. The labeling efficiency and viability were evaluated by Prussian blue staining. Such sonoporation technique can be employed for rapid labeling of various cells for MRI visualization of their spatiotemporal activities in vivo upon transplantation.

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Shape effect is an important parameter in the design of novel nanomaterials. Engineering the shape of nanomaterials is an effective strategy for optimizing their bioactive performance. Nanomaterials with unique shape...