Bioinspired nickel oxide nanoparticle as an efficient nanocarrier in the delivery of doxorubicin as an anti-bladder cancer drug

[Display omitted] •Cressa cretica plant extract as a green reducing and stabilizing agent to prepare NiO NPs.•HPLC revealed the best conditions of pH 7 and reaction time 9 h for loading of doxorubicin.•NiO-NPs have an averagesize of about 16 nm and a surface charge of −19.1 mV.•The highest drug loading of around 67% was attained onto NiO-NPs.•NiO-NPs showed paramagnetic behavior.•The MTT assay showed NiO-NPs are toxic against RT4 cell line with an IC50 of 500 mg/L. This study introduces Cressa cretica plant extract as a green reducing and stabilizing agent to prepare nickel oxide nanoparticles (NiO-NPs) from Ni(NO3)2·6H2O using the sol–gel method. Also, NiO-NPs were identified by XRD, FT-IR, FESEM, TEM, XPS, EDS, UV–Vis, TGA/DTA, VSM, DLS, and zeta potential techniques. Then, the synthesized NiO-NPs were loaded with doxorubicin drug and optimal conditions for the drug loading process such as pH of the reaction medium, reaction time, and amount of the nanoparticles were evaluated by the HPLC method. The results showed that NiO-NPs are pure with the averagesize of about 16 nm and surface charge of −19.1 mV. Additionally, the produced NiO-NPs showed strong super-paramagnetic behavior. Moreover, the loading of doxorubicin was well confirmed by FT-IR. From HPLC data, pH 6, reaction time 9 h, and nanoparticle amount of 0.01 g are the optimal conditions to achieve the highest drug loading around 67%. Furthermore, the MTT assay was used to study the cytocompatibility of NiO-NPs on the cancer RT4 cell line, and the cytotoxicity was confirmed along with an IC50 value of around 500 mg/L.