Taurine-Based Ionic Liquids for Transdermal Protein Delivery and Enhanced Anticancer Activity

Tumor is one of the most serious forms of abnormal growth that endangers human health today; its morbidity and mortality are both increasing every year. Most of the antitumor drugs used currently cannot be absorbed well by the human body because of their poor solubility and low bioavailability. Therefore, the prevention and treatment of tumors are still of high significance. These challenges can be addressed by the use of ionic liquids (ILs). Half of the antitumor drugs currently in the market are salts linked together by ILs. Compared to the solid form of the drug, the salt that is liquid at room temperature or body temperature shows good solubility, absorption, and stability. Therefore, in this study, we combined taurine with antitumor activity and alkaloids with biological activity (l-(-)-carnitine or betaine) to produce IL salts possessing the merits of both these components to develop an efficient and cost-effective drug delivery system for tumor treatment. Taurine-based ILs can deliver proteins such as insulin or dextran, which are promising drug delivery carriers. In vitro experiments showed that the taurine-based IL exhibited good biocompatibility, non-toxicity, and antitumor activity. Compared to the blank group, the proliferation inhibition rate of human colon adenocarcinoma cells (Caco-2) treated with different concentrations of taurine-based ILs increased significantly. The inhibitory effect of the taurine-based IL on Caco-2 cell proliferation became more pronounced with an increase in its concentration and the treatment time. Moreover, the results suggested that the combination of taurine-based ILs and chemotherapy drugs can improve the efficacy of chemotherapy drugs and reduce their adverse reactions. Interestingly, taurine-based ILs can inhibit the growth of tumor cells by inducing apoptosis in tumor cells after 4 h. This demonstrates the immense potential of taurine-based ILs in inhibiting the growth of tumor cells.