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Designed Fabrication of Unique Eccentric Mesoporous Silica Nanocluster-Based Core–Shell Nanostructures for pH-Responsive Drug Delivery

Chen, Lulu, Li, Lu, Zhang, Lingyu, Xing, Shuangxi, Wang, Tingting, Wang, Y. Andrew, Wang, Chungang, Su, Zhongmin
ACS Applied Materials & Interfaces 2013 v.5 no.15 pp. 7282-7290
acrylic acid, chemical elements, doxorubicin, fluorescence, image analysis, iron oxides, nanoparticles, pH, polyacrylic acid, porous media, prostatic neoplasms, silica
A novel and facile strategy using poly(acrylic acid) (PAA) as a nanoreactor and template has been proposed and applied for the first time to fabricate a novel and unique class of multifunctional eccentric Fe₃O₄@PAA/SiO₂ core–shell nanoclusters (NCs) consisting of a single Fe₃O₄ nanoparticle (NP), PAA, and eccentric SiO₂ NCs that are composed of a large number of small fluorescent SiO₂ NPs. Interestingly, the resulting eccentric PAA shell around Fe₃O₄ NPs as a high water-absorbent polymer is like a “reservoir” to absorb and retain water molecules inside its net structure to confine the growth of small SiO₂ NPs inside the PAA networks, resulting in the formation of an eccentric SiO₂ NC with aggregated pores. The thicknesses of uniform and well-dispersed SiO₂ NCs can also be precisely controlled by varying the amount of tetraethyl orthosilicate (TEOS). Importantly, the synthetic method has been confirmed to be universal and extended to other functional NPs with different compositions and shapes as eccentric cores. Furthermore, the as-prepared multifunctional eccentric Fe₃O₄@PAA/SiO₂ core–shell NCs combined fluorescence imaging, ultrahigh drug loading capacity (1.13 mg doxorubicin/mg eccentric NCs), and pH-responsive drug release into one were taken as an example to study the applications in simultaneous fluorescence imaging and pH responsive drug delivery into prostate cancer PC3M cells.