Water-soluble sulfonate porphyrin functionalized hyaluronic acid with comb-like structure: Potential photosensitizers for photodynamic therapy

Abstract

A water-soluble comb-like porphyrin polymer based on hyaluronic acid (HA) as the main chain and sulfonate substituted tetraphenylporphyrin (TASP) as side groups, named as HA-g-NH-TPP-(SO3Na) [(HA-g-TASP)], was designed and synthesized, which could be used as a potential photosensitizer in photodynamic therapy (PDT). This photosensitizer displayed high-water solubility, low dark cytotoxicity, high photocytoxiticy and high singlet oxygen yield (ΦΔ = 0.86). The HA-g-TASP was carefully characterized by UV–Vis, FTIR, and 1H NMR. UV–Vis spectra showed the Q bands of the HA-g-TASP spectrum had a significant red shift about 50 nm to near-infrared (NIR) region compared with TASP, the HA-g-TASP had a smaller energy band gap. The NIR region is known as the transparent window of the organisms, NIR irradiation shows larger penetration distance in tissue. As a novel photosensitizer, HA-g-TASP exhibited low cytotoxicity in dark and also low photocytotoxicity towards normal cells, but performed enhanced photodynamic activity against cancer cells (HeLa cells). As a result, HA-g-TASP with comb-like structure may be a useful photosensitizer for practical photodynamic therapy in the future.