Ccd112

The human colorectal cancer cell lines (HT29 and Caco-2) and normal cell line (CCD-112) were obtained from the American Type Culture Collection (ATCC). HT29 and Caco-2 cells were cultured in FA-deficient RPMI1640 medium (Gibco, Life Technologies), while the CCD-112 cells were grown in EMEM medium (ATCC) containing heat-inactivated foetal bovine serum (FBS, 10%). All cells were cultured at 37 °C in a humidified atmosphere of 5% CO₂ and 95% air and were passaged twice weekly.

The source of honey was from the Capilano Honey Limited (Australia). Standard graphene oxide (water dispersion, 4 mg/ml) was purchased from Graphene (U-Malaya). Copper II nitrate trihydrate (Cu(NO₃)₂.3H₂O, AR grade), ascorbic acid (C₆H₈O₆, AR grade), and sodium hydroxide (NaOH) were purchased from R&M Chemical, United Kingdom. All the chemicals were of analytical grade without further purification. Two Gram-positive bacteria, methicillin-resistant Staphylococcus aureus (MRSA, clinical isolate) and Enterococcus faecalis (E. faecalis, ATCC 33186), and two Gram-negative bacteria, Escherichia coli (E. coli, ATCC 11775) and Pseudomonas aeruginosa (P. aeruginosa, ATCC 10145), were used for antibacterial assessment. They were cultured and maintained in sterile Mueller–Hinton agar and broth media (Becton Dickinson, United States). The colorectal cancer cell line HCT116 (ATCC CCL-247) and human normal colon cell CCD112 (ATCC CRL-1541) were used for the cytotoxicity assay.

HCT116 (ATCC CCL-247) colorectal carcinoma and CCD112 (ATCC CRL-1541) colon normal cell lines were purchased from American Type Culture Collection (ATCC, United States). Both cell lines were maintained in Dulbecco’s Modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum (FBS) (Gibco) and 1% penicillin/streptomycin (Gibco). CellTiter 96 Aqueous One Solution or MTS reagent (#G3582, Promega) was purchased to evaluate the cytotoxicity of AuNPs, Au-AgNPs and Au-AgPCA NPs on the cell lines as described below.