A PROCESS FOR POLYETHYLENIMINE AND ORGANIC REDUCING AGENT -MEDIATED SYNTHETIC INSERTION OF GOLD NANOPARTICLES WITHIN MESOPOROUS SILICA NANOPARTICLES AND THEIR BIOMEDICAL APPLICATIONS
Mesoporous silica nanoparticles (MSNP) with control over pore size and nanogeometry can be used as an efficient and safe carrier for drug delivery and biocatalysis. The surface modification of such MSNPs using suitable reagent may provide a robust framework in which two or more components can be incorporated to give multifunctional capabilities specifically synthesis of noble metal nanoparticles within mesoporous architecture along with specific loading of bioactive molecule. We report herein the polyethylenimine (PEI) and formaldehyde mediated synthesis of gold nanoparticles in mesoporous architecture of silica nanoparticles using (a) unmodified MSNP and (b) 3-trihydroxysilylpropyl methylphosphonate modified MSNPs. The finding on these lines demonstrated the following (i) PEI enable synthetic incorporation of gold nanoparticles in the presence of formaldehyde in both unmodified and modified MSNP, (ii) An increase in PEI concentration results relative increase in the nanogeometry of gold nanoparticles during synthetic incorporation in MSNP, (iii) phosphonate modified MSNP yielded into relatively better nanogeomtery of AuNPs, (iv) Unmodified MSNP resulted with an increase in polycrystalline behavior of AuNPs (v) the catalytic activity of AuNPs incorporated within modified MSNP are better as compared to that recorded with unmodified MSNP. The MSNPs of average size of 200 nm with pore size between 4-6 are used for AuNPs synthesis. It has been found that PEI coating enable AuNPs synthesis within mesopores in the presence of formaldehyde or tetrahydrofuran hydroperoxide between 10-25 oC or at 60oC even in absence of organic reducing agents. AuNPs incorporated MSNP shows efficient biocatalyst as peroxidase mimetic. In addition to that paclitaxel can also be loaded in AuNPs modified MSNP justifying novelty in drug delivery. The AuNPs incorporated within mesoporous matrix have been characterized by transmission electron microscopy, EADX and HR SEM. The cation
