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

Abstract

The manganese doped zinc selenide nanoparticles (ZnSe:Mn NPs) were synthesized by thermolysis method using oleic acid and oleylamine as a capping agent, 1-octadecene as solvent. Coating of mesoporous silica was done on ZnSe:Mn (ZnSe:Mn@mSilica) which was further functionalized with amine functional groups by treating with (3-aminopropyl)trimethoxysilane. Further pegylation was done to achieve water dispersibility by conjugating carboxyl groups of poly(ethylene glycol) diacid with the amine groups. These pegylated NPs were subsequently treated with ethylenediamine followed by acrylic acid. Conjugation of tris-(hydroxymethyl-aminomethan) was performed by Michael-type addition reaction to afford ZnSe:Mn@mSilica-PEG-Tris-OH. These TRIS functionalized NPs 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 was 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) were observed.  This shows that our formulation has more cytotoxic in RAJI cancer cell lines than that of WEHI-164 cancer cells. These results revealed that the formulation has potential for the application in drug delivery and diagnosis in chemotherapeutics.