Synthesis and characterization of temozolomide loaded theranostic quantum dots for the treatment of brain glioma

Abstract

In the present study, we have synthesized a multifunctional nano-carrier for the targeted delivery of temozolomide to brain glioma cells. The synthesis involved the surface modification of Ag2S quantum dots (QDs) with PEG2000. Silver sulphide quantum dots (Ag2S QDs) have gained a lot of attention as a theranostic agent because they have outstanding optical and chemical features that make diagnosis and therapy easier at the same time. PEGylation of QDs provides active binding sites for the conjugation of other bio-molecules while also stabilising the carrier in a biological environment. Angiopep-2 (ANG-2), a 19-aa oligopeptide, was incorporated as a targeting agent for the specific targeting of the nano-carrier to the brain glioma cells. LRP1 (low-density lipoprotein receptor-related protein 1) is abundantly expressed in both brain capillary endothelial cells and glioma cells. Angiopep-2 can bind to LRP1 and use receptor-mediated transport to cross the blood–brain barrier. As a result, ANG can be employed to deliver drugs to both the brain and the tumour locations. Fourier transform infrared, ultraviolet-visible, and fluorescence spectroscopy were used to extensively examine the structural features and optical qualities. The efficiency of entrapment was determined to be 71±0.8%. At the lysosomal pH (pH 5.0), the prepared TMZ-ANG-PEG-QDs formulations show a sustained release pattern of TMZ (68.6±0.2 percent in 24 hr). Drug-loaded QDs had higher cytotoxicity and cellular uptake, and were taken up preferentially by malignant cells through receptor-mediated endocytosis pathways. As a result, we postulated that the synthesised QDs could be a good choice for theranostic applications, particularly for targeted drug delivery and cellular imaging at the same time.