MnAl Layered Double Hydroxide Nanoparticles as a Dual-Functional Platform for Magnetic Resonance Imaging and siRNA Delivery.

Multifunctional nanoparticles for cancer theranosis have been widely explored for effective cancer detection and therapy. In this work, dually functionalised manganese-based layered double hydroxide nanoparticles (Mn-LDH) were examined as an effective anticancer drug/gene delivery system and for T1 -weighted magnetic resonance imaging (MRI) in brain cancer theranostics. Such Mn-LDH have been shown to accommodate dsDNA/siRNAs and efficiently deliver them to Neuro-2a cells (N2a). Mn-LDH have also shown high biocompatibility with low cytotoxicity. Importantly, the cell-death siRNA (CD-siRNA) delivered with Mn-LDH more efficiently kills brain cancer cells than the free CD-siRNA. Moreover, Mn-LDH can act as excellent contrast agents for MRI, with an r1 value of 4.47 mm-1  s-1 , which is even higher than that of commercial contrast agents based on Gd complexes (r1 =3.4 mm-1  s-1 ). Altogether, the high delivery efficacy and MRI contrast capability make dual-functional Mn-LDH potential bimodal agents for simultaneous cancer diagnosis and therapy.