Abstract
Optically active organic nanoparticles capable of emitting strong near-infrared II (NIR-II) fluorescence and eliciting tumor hyperthermia are promising for tumor imaging and photothermal therapy (PTT). However, their applications for the treatment of pancreatic tumors via mere PTT are challenging as both the nanoparticles and light are hard to enter the deeply located pancreatic tumors. Here, we report a NIR-II light excitable, carbonic anhydrase (CA)-targeting cisplatin prodrug-decorated nanoparticle (IRNPs-SBA/PtIV) for NIR-II fluorescence imaging (FLI)-guided combination PTT and chemotherapy of pancreatic tumors. IRNPs-SBA/PtIV is designed to hold a high photothermal conversion efficiency (PCE ≈ 65.17 %) under 1064 nm laser excitation, a strong affinity toward CA (Kd = 14.40 ± 5.49 nM), and a prominent cisplatin release profile in response to glutathione (GSH) and 1064 nm laser irradiation. We show that IRNPs-SBA/PtIV can be actively delivered into pancreatic tumors where the CA is upregulated, and emits NIR-II fluorescence to visualize tumors with a high sensitivity and penetration depth under 980 nm laser excitation. Moreover, the tumor-resided IRNPs-SBA/PtIV can efficiently inhibit the CA activity and consequently, relieve the acidic and hypoxic tumor microenvironment, benefiting to intensify chemotherapy. Guided by the NIR-II FLI, IRNPs-SBA/PtIV is capable of efficiently inhibiting pancreatic tumor growth via combinational PTT and chemotherapy with 1064 nm laser excitation under a low-power density (0.5 W cm-2, 10 min). This study demonstrates promise to fabricate NIR-II excitable nanoparticles for FLI-guided precise theranostics of pancreatic tumors.