In this article, we introduce an innovative combination of phosphorene nanosheets functionalized by sialic acid, Apart from the functionalization of the phosphorene sheets with sialic acid, we have examined their biological effect on cancerous cells. The formation of crystalline phosphorene sheets is achieved using a hydrogen-assisted plasma processing. The functionalization of the phosphorene is feasible through immersion of the freshly prepared sheets in a sialic-acid containing solution, leading to the formation of covalent bonding of bio-molecule with the phosphorus atoms on the sheet. We have investigated the toxicity of the prepared sheets and their efficacy in drug delivery using a combination of material and biological assays. For the cancer cells, we have used MDA-MB-231 cell line which is a highly metastatic breast cancer line. We used Doxorubicin medication either loaded on bio-phosphorene or in a lonely administration.
Apart from high stability of the treated bio-phosphorene sheets, their toxicity and efficacy have been examined on the aforementioned cell line. We have used both MTT and flow cytometry analysis to observe the rate of survival or death of the treated cells using various methods. The addition of sialic-acid molecules to the bio-phosphorene leads to a constructive effect on the stability of the sheets in air and aqueous solution. The viability rate for the unloaded bio-phosphorene sheets on MDA-MB-231 cells remains as high as 90% if the concentration of bio-phosphorene sheets stands between 25 and 167 μg/mL. In addition, the viability drops to values close and smaller than 50%, if a combination of infra-red illumination and DOX drug treatment is used. By referring to the data obtained in this research, we believe the use of bio-phosphorene sheets can be considered as a vehicle for drug delivery to increase the death rate of highly cancerous cells, while less aggressive and healthy cells remain non-affected.