Research trends and hotspots of upconversion nanoparticles for drug delivery and biomedical targeting in photodynamic therapy

UCNP-PDT has evolved from simple photosensitizer loading to multifunctional nanoplatforms, expanding applications to cancer therapy, infection control, and immune modulation. Clinical translation remains limited by size-efficiency trade-offs, low-power irradiation, hypoxia, tissue heating under 980 nm excitation, GMP-compliant production, and insufficient long-term biosafety data. Future advances require coordinated strategies integrating material optimization, mechanistic insight, and translational considerations to achieve safe, scalable, and effective UCNP-PDT for clinical use.