A robust graft-to strategy to form multifunctional and stealth zwitterionic polymer-coated mesoporous silica nanoparticles.

Mesoporous silica nanoparticles (MSNs) are a new class of carrier materials promising for drug/gene delivery and many other important applications. Stealth coatings are necessary to maintain their stability in complex media. Herein, a biomimetic polymer conjugate containing one ultralow fouling poly(carboxybetaine) (pCBMA) chain and one surface-adhesive catechol (DOPA) residue group was efficiently grafted to the outer surface of SBA-15 type MSNs using a convenient and robust method. The cytotoxicity of SBA-15-DOPA-pCBMAs was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results showed no significant decrease in cell viability at the tested concentration range. Macrophage cell uptake studies revealed that the uptake ratios of SBA-15-DOPA-pCBMAs were much lower than that of parent MSNs. Furthermore, inductively coupled plasma mass spectrometry (ICP-MS) analysis results showed that after SBA-15-DOPA-pCBMAs were conjugated with a targeting cyclo-[Arg-Gly-Asp-d-Tyr-Lys] (cRGD) peptide, uptake by bovine aortic endothelial cells (BAECs) was notably increased. Results indicated that cRGD-functionalized MSNs were able to selectively interact with cells expressing αvβ3 integrin. Thus, MSNs with DOPA-pCBMAs are promising as stealth multifunctional biocarriers for targeted drug delivery or diagnostics.