Gastric cancer is one of the most common cancers in modern societies. Previous studies have shown that the use of nanoparticle complexes is effective in the treatment of cancer. The aim of this study was to investigate the cytotoxicity and anticancer properties of cobalt oxide (Co 3 O 4 ) nanoparticles (NPs) functionalized by glutamic acid (Glu) and conjugated with thiosemicarbazide (TSC) on gastric cancer (AGS) cell line. First, the Co 3 O 4 @Glu/TSC nanoparticles were synthesized via co-condensation reaction. Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) tests were performed for identifying the morphology, structure, size and functional groups of produced nanoparticles. MTT assay was also performed to evaluate cytotoxicity effect. Moreover, Annexin V/PI staining with flow cytometry analysis, caspase-3 activation assay, and Hoechst 33258 staining was carried out for evaluating apoptosis. The FTIR results showed that the components of Co 3 O 4 @Glu/TSC NPs complex were successfully fabricated. Crystallographic structure of Co 3 O 4 @Glu/TSC NPs was confirmed by XRD patterns. SEM results indicated that the size of the nanoparticles was in the range of 16-40 nm. An EDX spectrum was determined and data explained the existence of cobalt as the prominent element. MTT test results showed that AGS cell life was significantly decreased compared to the control group with increasing concentration of nanoparticles (dose-dependent) (P < 0.05), IC 50 = 107.5 μg/mL. The results of flow cytometry assay and caspase-3 activity showed that fabricated Co 3 O 4 @Glu/TSC NPs induced apoptosis in the treated group. Moreover, Co 3 O 4 @Glu/TSC NPs treated AGS cells indicate an increase in the apoptotic characteristics including nuclear fragmentation. In the current work, the promising cytotoxicity and anti-cancer activities of Co 3 O 4 @Glu/TSC NPs complex toward gastric cancer (AGS) cell line were showed and it can be suggested for the drug delivery system.

Purpose Gastric carcinoma is the fourth most common malignancy worldwide and remains the second cause of death of all malignancies worldwide. Today, despite advances in treatment, cancer is still the second leading cause of death worldwide. In the meantime, nanotechnology has helped to achieve fast and effective treatment. Today, Thiosemicarbazones has emerged as a new wave of drugs in recent years. Since these compounds alone have not been very successful in treating cancer, combining them with different nanoparticles has significantly increased the chances of success. Methods In this study, first Zinc Oxide (ZnO) nanoparticles were synthesized and then functionalized by glutamine (Gln) and finally conjugated to Thiosemicarbazide (ZnO@Gln-TSC) by co-precipitation method. Physicochemical method including FTIR, DLS, XRD, EDS-map, Zeta-potential, field emission scanning electron microscopy (FESEM) and imaging electron microscopy (TEM) techniques were used to investigate the synthesis of ZnO@Gln-TSC nanoparticles. The toxicity effects of ZnO@Gln-TSC nanoparticles and Oxaliplatin drug at different concentrations were investigated by MTT assay on adenocarcinoma gastric (AGS) cell line and normal cell line (HEK293). Apoptosis (programmed cell death) was also evaluated by Flow cytometry (Annexin V/ PI kit), cell cycle analysis and Hoechst staining. Results The synthesis of ZnO@Gln-TSC nanoparticles (NPs) was confirmed by chemical confirmation tests. The size of synthesized NPs was reported in the range of 40 to 70 nm. Also, a number of -31.7 mV in the Zeta-potential test indicated the stability of the produced nanoparticle. EDS analysis showed the elements of final NPs. DLS analysis showed the size of the hydrated NP at 374 nm. MTT test showed that the IC50 of NPs was 9.8 µg/ml and Oxaliplatin drug 65.7 µg/ml for cancer cells in comparison the IC50 of 150 µg/ml for normal cells. Hoechst staining confirmed that the NPs can induce apoptosis and cell death in cancer cell line. Flow cytometry analysis showed apoptosis induction among NPs treated cells than controls with the frequency of 55.5% and 9.48% for the early and late apoptosis, respectively. Conclusion This study revealed the promising anticancer potential of NPs to be used for gastric cancer treatment after further characterization using in-vitro and in-vivo assays.