Here, a novel super‐long, ultraviolet A region (UVA), persistent luminescent (PerL) material, LiYGeO4:Bi3+, is developed. After irradiation at 254 nm for 10 min, the UVA PerL of LiYGeO4:Bi3+ can persist for more than 300 h. In addition, the LiYGeO4:Bi3+ also possesses a strong UVA emission with a power density of 11.83 mW m−2 at 10 s after the removal of the excitation source. Even after 72 h, the UVA PerL emission spectrum can still be clearly detected, which is the same as the photoluminescence emission spectrum and originated from the Bi3+ emitting centers. Furthermore, LiYGeO4:Bi3+ also exhibits a photostimulated PerL property, which can be easily activated with a red light emitting diode (LED) or NIR laser irradiation after the long‐term decay. Combining the results of the PerL excitation, absorption, and thermoluminescence spectra, the excellent UVA PerL of LiYGeO4:Bi3+ can be ascribed to the existence of abundant trap sites created by the loss of Li+. This excellent PerL material can make up for deficiency of PerL materials in the UVA region and greatly expand the application of PerL materials in the biomedical, energy, environmental, and catalysis fields.
The
photodynamic therapy (PDT) as a promising antitumor therapy
technique is greatly hampered by the low tissue penetration of light
and the photothermal effect of prolonged irradiation. Near-infrared
(NIR) persistent luminescence nanoparticles (NPLNPs) possess the potential
for application in next-generation PDT. However, owing to the low
re-excitation efficiency of NPLNPs in deep tissue, the current PDT
nanoplatform based on NPLNPs is faced with the disadvantage of decreased
PDT efficiency induced by persistent luminescence (PersL) decay at
the lesion site. Herein, NPLNPs, Zn1.3Ga1.4Sn0.3O4:Cr3+ (ZGS), with small particle
sizes and excellent optical properties are synthesized via a simple
acetylacetonate combustion method. The ZGS can be repeatedly excited
by the biological window (659 nm) light to produce a strong NIR (700
nm) PersL. The response efficiency of ZGS to the wavelength in the
biological window has been greatly improved by doping Sn4+ into the ZnGa2O4 matrix, which is 55 times
higher than that of traditional ZnGa2O4:Cr3+. We further develop a PDT nanoplatform by modifying a photosensitizer
on its surface. The PDT experiments show that the developed nanoplatform
can achieve continuous and efficient tumor PDT with a depth of up
to 3 cm by repeated excitation using a 659 nm LED. The NPLNPs largely
solve the problem of the low re-excitation efficiency after NIR PersL
decay of traditional NPLNPs in deep tissue applications and will further
promote the application of NIR PLNPs in the biomedical field.
Immunotherapy holds great promise for cancer treatment. The key to improving the therapeutic effect is to drive the patient's own immune system to produce a strong, effective, and enduring tumor-specific immune response. Engineered nanoplatforms show promising potential in strengthening antitumor immune responses. However, current nanotherapeutic platforms based on exogenous responses stimulate the immune system only in a transitory and limited manner, which translates into insufficient immune activation and a low therapeutic efficacy. A novel targeted nano-immunostimulant (ZGS-Si-Pc@HA) is fabricated by coupling persistent luminescence nanoparticles with a photosensitizer and hyaluronic acid for sustained immune stimulation upon irradiation with biological window (659 nm) light. ZGS-Si-Pc@HA persistently drives reactive oxygen species production to induce immunogenic cell death, causing a durable tumor-specific immune response. Upon intratumoral injection, ZGS-Si-Pc@HA effectively alleviates immune tolerance and promotes T lymphocyte tumor infiltration. Further, ZGS-Si-Pc@HA enhances the therapeutic effect of checkpoint blockade immunotherapy, effectively inhibiting bilateral tumor growth and triggering an immunological memory effect. Nano-immunostimulants not only provide a new way to boost cancer immunotherapy, but also offer a reliable strategy for fighting cancer metastasis and recurrence clinically.
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