POS8-1644
Cryo-Enhanced Upconversion Photodynamic Therapy
Topic
S8. Frontiers of Functional Polymers in Biology and Medicine
When and Where
Oct 1, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Jinkee HONG
Ki Su KIM
Presenter(s)
Anara Molkenova (Pusan National University)
Co-Author(s)
Abstract
Upconversion photodynamic therapy (PDT) has emerged as a promising localized therapeutic strategy for cancer treatment by enabling remote activation of ultraviolet and visible light-mediated photodynamic processes using near-infrared (NIR)-excitable upconversion nanoparticles (UCNPs). However, the clinical translation of PDT remains challenging because the relatively low luminescence efficiency of UCNPs limits the generation of sufficient therapeutic output under skin-safe NIR irradiation conditions. Recent studies have demonstrated that UCNP luminescence can be substantially enhanced at cryogenic temperatures through suppression of thermally induced quenching. Here, we exploit this phenomenon to establish a cryo-enhanced upconversion photodynamic therapy (Cryo-PDT) strategy. We developed 808-nm-excitable UCNPs using a facile and accelerated synthetic approach and demonstrated a 2.5-fold enhancement in photoluminescence intensity under cryogenic conditions. A multifunctional therapeutic nanoplatform comprising porous silica-coated UCNPs, chlorin e6 (Ce6), and hyaluronic acid (UCNPs@SiO₂-Ce6-HA) was subsequently developed for NIR-triggered treatment of skin cancer. Ex vivo studies demonstrated that cryogenic enhancement of UCNP luminescence increased Ce6-mediated singlet oxygen generation by 3.15-fold. In vitro studies further confirmed the biosafety, cancer-cell targeting, and NIR-triggered cytotoxicity of the nanoplatform, while porcine skin models demonstrated efficient transdermal delivery. Importantly, consecutive freezing and 808-nm NIR irradiation produced a synergistic tumoricidal effect in melanoma-bearing mice, resulting in 1.44-fold greater tumor eradication compared with conventional PDT alone. Collectively, these findings establish Cryo-PDT as a promising strategy for overcoming the limited optical output of UCNPs and improving the efficacy of NIR-mediated photodynamic cancer therapy.
