Ce[sup 3/4+] cation-functionalized maghemite nanoparticles towards siRNA-mediated gene silencing.

Pre-formed Massart magnetite (Fe[sub 3]O[sub 4]) nanoparticles (NPs) have been successfully modified by positively charged lanthanide Ce(III/IV) cations/[CeLJ3/4+ complexes by using a strong mono-electronic Ceric Ammonium Nitrate oxidant (CAN) as a Ce donor. The doping process is promoted by high-power ultrasonic irradiation. The reaction has been statistically optimized by Design of Experiments (DoE, MINITAB® 16 DoE software) to afford globally optimized magnetically responsive ultra-small 6.61 ± 2.04 nm-sized CAN[sub DOE]-γ-Fe[sub 2]O[sub 3] NPs that are highly positively charged (ξ potential: +45.7 mV). This innovative inorganic DoE-optimized NP surface modification by [CeL[sub n][sup 3/4+] complexes enables an effective "fully inorganic-type" coordination attachment of a branched poly-cationic 25 kDa b-PEI[sub 25] polymer for siRNA loading and gene silencing. This innovative NP platform technology paves an efficient way for the successful development of a wide range of biomedicine and diagnostic-related applications. [ABSTRACT FROM AUTHOR]