Supramolecular Self-Assembly of g-C₃N₄ Nanoplatform as Drug Delivery Carriers for Cancer Therapy

Graphite carbon nitride (g-C3N4) polymer with two-dimensional planar structure is a new star in nanodrug delivery systems in recent years because it shows characteristics of low cost, nontoxicity, biocompatibility and easy functionalization. However, conventional g-C3N4 shows bulk, macro size, small specific surface area and poor water solubility. To improve this, most works are always confined to physical ultrasound, oxidative peeling or template-strategy, which have the disadvantages of redundant steps, environment-unfriendliness and high cost. In this paper, a modified supramolecular self-assembled strategy was carried out to construct a novel graphitic carbon nitride nanoplatform (named by CA-MA(X)) using melamine and cyanuric as precursors. The chemical structure characterization, drug loading experiment and cell tests in vitro of the CA-MA(X) nanoplatform were carried out and discussed in detail. Results indicated that the obtained samples show enhanced specific surface area, more exposed groups and good biocompatibility. Compared to the traditional carbon nitride (named by MA-CN), the newly prepared CA-MA(X) carrier shows improved drug loading efficiency and good pH-responsive loading, as well as releasing. Cell uptake experiment demonstrates that CA-MA(2)-DOX can be swallowed by cancer cells and during treatment of the cancer cell process, the CA-MA(2)-DOX complex experiences phagocytizing by the cancer cell, controlled-release DOX and kills the cancer cell after DOX was passively diffused into the nucleus. CA-MA(2)-DOX exhibited significant in vitro antitumor activity. To our knowledge, this is the first time the supramolecular self-assembled method was used in carbon nitride nanocarrier construction for cancer treatment.