One pot synthesis of luminescent Mn doped ZnSe nanoparticles and their silica based water dispersible formulation for targeted delivery of doxorubicin

Abstract

The manganese doped zinc selenide nanoparticles (ZnSe:Mn NPs) have been synthesized by thermolysis method using oleic acid and oleylamine as capping agents, and 1-octadecene as solvent. Coating of mesoporous silica is done on ZnSe:Mn (ZnSe:Mn@mSilica) which is further functionalized with amine functional groups by treating with (3-aminopropyl)trimethoxysilane. Further pegylation is done to achieve water dispersibility by conjugating carboxyl groups of poly(ethylene glycol) diacid with the amine groups. These pegylated NPs are subsequently treated with ethylenediamine followed by acrylic acid. Conjugation of tris-(hydroxymethyl-aminomethane) is performed by Michael-type addition reaction to afford ZnSe:Mn@mSilica-PEG-Tris-OH. These tris functionalized NPs have exhibited broad emission ranging from 590-620 nm that is an indicative for their suitability in diagnosis and monitoring progress of cancer treatment. To explore the usefulness of increased surface area because of mesoporosity, doxorubicin is loaded on ZnSe:Mn@mSilica-PEG-Tris-OH NPs through silyl ether linkage and evaluated for cytotoxicity against WEHI-164 mouse fibrosarcoma and RAJI human hematopoietic origin cancer cell lines. A decrease in 12% of cell viability of WEHI-164 cells while 30% decrease in RAJI cell lines (IC₅₀ ≈ 45 nM) are observed. This shows that our formulation has more cytotoxic in RAJI cancer cell lines than that of WEHI-164 cancer cells. These results reveal that the formulation has potential for the application in drug delivery and diagnosis in chemotherapeutics.