Study On Preparation And Application Of Multifunctional Nano-therapeutic Preparation

Cancer has great danger to human life and health, so early diagnosis and treatment of cancer is very important.Molecular imaging has attracted more interesting in recent years for its advantages in providing in vivo information for diagnosis and the monitoring of disease.Among various imaging techniques, ultrasound imaging is noteworthy for its real-time, cost effectiveness, portability, and wide availability.However, the weak difference in echogenicity between different tissues often hampers diagnosis. In order to better visualize specific tissues, ultrasound contrast agents(UCAs)are frequently used.The agents alter or enhance the returning ultrasound signal and provide improved surface or tissue resolution. For this purpose,gas-filled microbubbles are developed to enhance the ultrasound signal. Unfortunately, the air microbubbles dissolve and collapse within seconds after injection into the bloodstream because of the effect of Laplace pressure, blood pressure, oxygen metabolism, and exposure to ultrasound energy.Alternatively, inorganic based hollow capsule materials, such as hollow silica nano-/micro-spheres, may be another choice for UCAs. Silica has been suggested in the literature to be a highly biocompatible and mechanically stable substance. Its surface canbe easily modified with amino, thiol, and carboxyl groups which would in turn facilitate the linking of bioconjugators. This property satisfies the requirement for use in pharmaceutics and biochemistry.Herein, we describe the development of Fe3O4 grafted hollow silica spheres[abbreviated as Fe3O4–HSS]based on sacrificing the polystyrene template to fabricate hollow silica spheres.Investigations by cytotoxicity test, hemolysis assay, and MRI imgaing have proved that the Fe3O4–HSS have low cytotoxicity, good blood compatibility and cell permeability. Finally, the Fe3O4–HSS have been used for in vivo ultrasound imaging, which makes them promising candidates as novel UCAs.The gold nanoparticles were deposited on the surface of hollow silca spheres via electrostatic adsorption to form gold nanoshelled microcapsule The gold nanoshelled microcapsule were proved to have great capabilities of ultrasound contrast enhancement as well as NIR photothermal therapy. That demonstrated the feasibility of the combination of ultrasound contrast imaging and NIR photothermal therapy as novel theranostics.