Incorporation of gene therapy vector in chitosan stabilized Mn2+-doped ZnS quantum dot

Chitosan stabilized and water soluble (pH ≤ 6.5) ZnS:Mn2+ quantum dots (QDs) of ca. 3.6 nm having a strong orange fluorescence have been synthesized in an environment friendly method. Binding of plasmid DNA containing the bifunctional cytosine deaminase-uracilphosphoribosyl transferase (pCD-UPRT) gene with therapeutic importance in suicide gene therapy has been investigated and shown to follow the Langmuir reversible adsorption model. The biocompatibility of the composite on HT29 cells was confirmed by the viability assay. The chitosan stabilized ZnS:Mn2+ QDs synthesized in the present study could be a promising alternative to conventional organic fluorophore-tagged gene delivery systems for real-time monitoring in gene therapy applications.