20:T4f4,Luminescence quenching at high dopant concentrations generally limits the dopant concentration to less than 1-5 mol% in lanthanide-doped materials, and this remains a major obstacle in designing materials with enhanced efficiency/brightness. In this work, we provide direct evidence that the major quenching process at high dopant concentrations is the energy migration to the surface (i.e., surface quenching) as opposed to the common misconception of cross-relaxation between dopant ions. We show that after an inert epitaxial shell growth, erbium (Er³⁺) concentrations as high as 100 mol% in NaY(Er)F₄/NaLuF₄ core/shell nanocrystals enhance the emission intensity of both upconversion and downshifted luminescence across different excitation wavelengths (980, 800, and 658 nm), with negligible concentration quenching effects. Our results highlight the strong coupling of concentration and surface quenching effects in colloidal lanthanide-doped nanocrystals, and that inert epitaxial shell growth can overcome concentration quenching. These fundamental insights into the photophysical processes in heavily doped nanocrystals will give rise to enhanced properties not previously thought possible with compositions optimized in bulk.21:T445,Photodynamic therapy (PDT) is ineffective against deeply seated metastatic tumors due to poor penetration of the excitation light. Herein, we developed a biomimetic nanoreactor (bio-NR) to achieve synergistic chemiexcited photodynamic-starvation therapy against tumor metastasis. Photosensitizers on the hollow mesoporous silica nanoparticles (HMSNs) are excited by chemical energy in situ of the deep metastatic tumor to generate singlet oxygen (¹O₂) for PDT, and glucose oxidase (GOx) catalyzes glucose into hydrogen peroxide (H₂O₂). Remarkably, this process not only blocks the nutrient supply for starvation therapy but also provides H₂O₂ to synergistically enhance PDT. Cancer cell membrane coating endows the nanoparticle with biological properties of homologous adhesion and immune escape. Thus, bio-NRs can effectively convert the glucose into ¹O₂ in metastatic tumors. The excellent therapeutic effects of bio-NRs in vitro and in vivo indicate their great potential for cancer metastasis therapy.

	Year	Citations

References