Nanofluid-Enhanced Laser Lithotripsy Using Conducting Polymer Nanoparticles

Abstract

Urinary stone disease, characterized by the hard mineral deposits in the urinary tract, has seen a rising prevalence globally. This condition often leads to severe pain and requires medical intervention. Laser lithotripsy, a minimally invasive treatment, uses laser to fragment urinary stones to facilitate removal or natural passage. Among available laser technologies, Ho:YAG laser has established itself as the gold standard for three decades. Efforts to improve ablation efficiency have focused on laser parameters such as pulse energy and frequency. This study introduces an ablation enhancement strategy that incorporates nanoparticles with strong near-infrared absorption into the surrounding fluid to enhance light-matter interaction. Using 0.03 wt.% PEDOT:PSS nanofluid improves stone ablation efficiency by 38-727% in spot treatment and 26-75% in scanning treatment with a clinical Ho:YAG laser lithotripter. The highly absorbing nanofluid accelerates vapor tunnel formation, boosts laser energy transmission, and permeates stone pores to enhance damage, without increasing thermal tissue injury. Cytotoxicity tests also confirmed minimal toxicity at appropriate concentrations. This nanofluid-based approach offers a promising advancement for more efficient and safer laser lithotripsy. Further work should address the remaining challenges for clinical translation, including aggregation in saline, efficacy in real human kidney stones, and comprehensive animal studies.

Keywords: Ho:YAG laser; NIR absorber; conducting polymers; kidney stone disease; laser lithotripsy.