Indocyanine Green-Loaded Mesoporous Silica Nanocomposite for Breast Cancer Imaging

Fluorescence imaging is essential for tumor staging and treatment decision-making. However, indocyanine green (ICG) imaging still faces challenges in terms of stability and targeting specificity despite improvements in penetration depth and the signal-to-noise ratio. To address these issues, a nanocomposite fluorescence probe called ICG@MSNs-PEG-Ab has developed. This probe involves coupling an anti-PD-L1 antibody to mesoporous silica nanoparticles (MSNs) loaded with ICG and coated with polyethylene glycol (PEG). The ICG@MSNs-PEG-Ab nanocomposite probe demonstrates excellent biocompatibility and emits strong and stable fluorescence in the near-infrared second region (NIR-II) when it is exposed to 808 nm laser irradiation. Importantly, it outperforms free ICG in terms of prolonged retention in the body and increased resistance to photodegradation. By combining passive targeting of the enhanced permeability and retention effect with active targeting of the interaction between the anti-PD-L1 antibody and antigen, ICG@MSNs-PEG-Ab selectively targets PD-L1-positive hormonal nude mice. This achievement enables high-performance NIR-II imaging, allowing for rapid and precise in vivo tumor identification with an impressive tumor-to-muscle contrast ratio of 3.94. This work provides valuable insights into the design of high-quality NIR-II fluorescence probes for accurate tumor diagnosis and targeted drug delivery.