On the potential of the WSi12 superatom as a drug carrier: a DFT study.

The adsorption behaviors of 5-fluorouracil (5-Fu), 5-aminosalicylic acid (5-ASA), isoniazid (INH), 6-thioguanine (6-TG), and temozolomide (TMZ) onto the WSi12 superatom have been studied using density functional theory calculations to explore its potential application in drug delivery. Our results demonstrate that 5-Fu is bound to WSi12via very weak interaction with a small Ead value of -11.62 kcal mol-1, while the tight adsorption of TMZ greatly deforms this superatom and results in a high Edef value of 86.92 kcal mol-1, suggesting that WSi12 is not suitable to serve as a carrier for these two drugs. Fortunately, 5-ASA, INH, and 6-TG can be effectively bound to WSi12via forming polar covalent bonds in the resulting 5-ASA@WSi12, INH@WSi12, and 6-TG@WSi12 with the Ead values of -25.71 kcal mol-1, -19.65 kcal mol-1, and -24.24 kcal mol-1, respectively. As a result, the recovery time for the release of these drugs is moderate, indicating that this superatom can be regarded as a potential carrier for 5-ASA, INH, and 6-TG. Moreover, it is found that the Ead value of 6-TG@WSi12 is reduced from -24.24 to -15.29 kcal mol-1 under weakly acidic conditions, and the drug delivery performances of WSi12-extended WnSi6(n+1) (n = 2, 4, and 6) nanostructures are better than that of a single WSi12 superatom. We hope that this study could provide a valuable reference for further experiments on using such WSin clusters as novel drug delivery carriers.