In this study, we propose doxorubicin (DOX) loaded oligonucleotides (ONTs) attached to gold nanoparticles (AuNPs) as a drug delivery system for cancer chemotherapy. DOX is one of the representative cancer chemotherapy agents and is widely used by many researchers as a chemotherapy agent in the drug delivery system. Due to the advantages of AuNPs such as simple steps in synthesis, high surface-area-to-volume ratio, and biocompatibility, we utilized AuNPs as drug delivery vehicle. AuNPs were synthesized by chemical reduction to be 13 nm diameter. The G-C rich oligonucleotides were used both for drug loading sites and AuNPs capping agents. 80% of DOX in solution could be bound to ONTs on AuNPs to became DOX-loaded AuNPs coated with ONTs (Doxorubicin-Oligomer-AuNP, DOA), and about 28% of loaded DOX was released from the as-prepared DOA. Confocal microscopy observation showed that DOA was well transported into cells, and finally the DOX was released into the cell nucleus. The drug's efficacies such as in vitro cytotoxicity and in vivo tumor growth inhibition were demonstrated with SW480 colon cancer cell line and a xenograft mouse model. MTT assay was performed to see the cytotoxicity effect on SW480 cells treated with DOA for 24 h, and the cell viability was determined to be 41.77% (p < 0.001). When DOA was administered regularly to a tumor bearing mouse, the tumor growth inhibition degree was examined by measuring the tumor size. The treatment-control (T/C) ratio was found to be 0.69. Thus, our results suggest the use of DOAs as promising drug delivery systems for colorectal cancer therapy.
Keywords: Colorectal cancer; Doxorubicin; Drug delivery; Gold nanoparticle; Nanomedicine.
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