Sensitive, Real-Time, and In-Vivo Oxygen Monitoring for Photodynamic Therapy by Multifunctional Mesoporous Nanosensors

Real-time monitoring of oxygen consumption is beneficial to predict treatment responses and optimize therapeutic protocols for photodynamic therapy (PDT). In this work, we first demonstrate that deformable hollow mesoporous organosilica nanoparticles (HMONs) can be used to load [(Ru(dpp)₃)]Cl₂ for detecting oxygen (denoted as HMON-[(Ru(dpp)₃)]Cl₂). This nanoprobe shows significantly improved biocompatibility and high cellular uptake. In-vitro experiments demonstrate that the HMON-[(Ru(dpp)₃)]Cl₂ can sensitively detect oxygen changes between 1% and 20%. On this basis, photosensitizer chlorin e6 (Ce6) and [(Ru(dpp)₃)]Cl₂ are simultaneously loaded in the HMONs (denoted as HMON-Ce6-[(Ru(dpp)₃)]Cl₂) for real-time oxygen monitoring during photodynamic therapy. The HMON-Ce6-[(Ru(dpp)₃)]Cl₂ can reflects oxygen consumption in solution and cells in photodynamic therapy. Furthermore, the ability of the HMON-Ce6-[(Ru(dpp)₃)]Cl₂ nanosensor to monitor oxygen changes is demonstrated in tumor-bearing nude mice.