In the present study, the targeted drug-carrying and detecting properties of the carmustine anticancer drug by pure B3O3 sheet have been explored with the help of periodic density functional theory. The results reveal that the drug-loaded on a pure B3O3 sheet has reduced the band gap by about the 28–32%; thus, it can detect the drug well. The band structure and density of states fully support the reduction in the band gap. Hirshfeld charge analysis confirms the charge transfer from the carmustine anticancer drug towards the sheet. In the most stable configuration, adsorption energy values in the gas and water phases for the drug-loaded on the B3O3 sheet are − 1.09 and − 0.58 eV, respectively. The parallel position is the most stable interaction between the drug and the surface. In the absence of radiation, the calculated recovery time at 306 K (normal cell temperature) and 310 K (brain tumor tissue temperature) are 3.7 × 10− 3 and 2.8 × 10− 3 s, respectively. According to the analyzes done by using the molecular dynamics (NVT module) at 310 K temperature, after being adsorbed carmustine anticancer drug on the pristine B3O3 substrate, the drug is released from the nanocarrier in the adjacency of tumor cells, and the therapeutic operation is carried out on the target cells