A Versatile Theranostic Delivery Platform Integrating Magnetic Resonance Imaging/Computed Tomography, pH/cis-Diol Controlled Release, and Targeted Therapy

The functions of biomedical imaging, cancer targeting, and controlled release of therapeutic agents were integrated into a drug delivery platform to proof its diagnostic and therapeutic capabilities. This versatile nanocomposite is based on the strategic design of wormlike mesoporous silica nanocarriers that are decorated with extremely small iron oxide nanoparticles, having a prominent T1-weighted Magnetic Resonance Imaging (MRI) signal. The controlled release function was then achieved through the grafting of polyalcohol saccharide derivative ligands onto the surfaces of mesoporous silica nanoparticles to conjugate with boronic acid functionalized gold nanoparticles, which acted as the gate and the source of computed tomography (CT) signals. This versatile platform thus exhibited a MRI/CT dual imaging property drawing on the strong points to offset the weaknesses of each, rendering more accurate diagnosis. The capping of gold nanoparticles controlled with the hydrolysis of boronate ester bonds provides the reversible opening/closing process, avoiding further release of drug once the nanocomposite leaves the cell or tissue. To endow this platform with targeting ability, protocatechuic acid was utilized as a linker to connect folic acid with the boronic acid of the gold nanoparticles. The anchor of targeting moiety, folic acid, enriched this platform and enhanced the specific cellular uptake toward cells with folate receptor. This integrated drug delivery platform was then loaded with the antitumor agent doxorubicin, demonstrating its power for targeted delivery, bioimaging, and controlled release chemotherapy to reduce the undesired side effects of chemotherapy.