Cross-Linked Pillar[6]arene Nanosponges Fabricated by the Use of a Supra-Amphiphilic Template: Cargo Encapsulation and Overcoming Multidrug Resistance

We report a general fabrication method for water-soluble pillar[n]arene nanosponges (NS) by the use of a supra-amphiphilic template. For the first time, a supra-amphiphilic template is used to conveniently control the size of host molecule-based NS. The intrinsic cavity of water-soluble pillar[6]arene could stably encapsulate dyes (acridine orange and indocyanine green) and antitumor drugs (doxorubicin hydrochloride and mitoxantrone) by host-guest interaction. NS could deliver antitumor drugs to cancer cells. Multidrug resistance (MDR) of cancer cells (MCF-7/ADR) is overcome by the use of NS with a ninefold reduction in the IC₅₀ value compared to that of the free drug (3.4 μM vs 34.4 μM). Mechanistic studies show that stable encapsulation of the antitumor drug is the reason to overcome MDR.