Supramolecular\nPhotoactivatable Anticancer Hydrogels

Abstract

A photoactivatable\ndopamine-conjugated platinum­(IV) anticancer\ncomplex (<b>Pt-DA</b>) has been incorporated into G-quadruplex\nG₄K⁺ borate hydrogels by using borate ester\nlinkages (<b>Pt-G</b>_<b>4</b><b>K</b>^<b>+</b><b>B</b> hydrogel). These were characterized\nby ¹¹B NMR, attenuated total reflection Fourier transform\ninfrared spectroscopy, circular dichroism, scanning electron microscopy\nand transmission electron microscopy. Microscopy investigations revealed\nthe transformation of an extended fiber assembly into discrete flakes\nafter incorporation of <b>Pt-DA</b>. <b>Pt-DA</b> showed\nphotocytotoxicity against cisplatin-resistant A2780Cis human ovarian\ncancer cells (IC₅₀ 74 μM, blue light) with a photocytotoxic\nindex <2, whereas <b>Pt-G</b>_<b>4</b><b>K</b>^<b>+</b><b>B</b> hydrogels exhibited\nmore potent photocytotoxicity (IC₅₀ 3 μM, blue light)\nwith a photocytotoxic index >5. Most notably, <b>Pt-DA</b> and <b>Pt-G</b>_<b>4</b><b>K</b>^<b>+</b><b>B</b> hydrogels show selective phototoxicity\nfor cancer\ncells versus normal fibroblast cells (MRC5).