Hollow AgAu-DTTC-BSA: a promising imaging assisted photothermal agent

Surgical resection is currently the primary treatment option for most malignant tumors. However, it remains to be a formidable challenge to remove tumor lesions in a precise and thorough manner. Recurrent abdominal malignancies, such as colon and ovarian cancers, are highly invasive and metastatic, and can migrate to surrounding tissues and critical organs in an immersive way. For this reason, imaging techniques, such as positron emission tomography (PET) and magnetic resonance imaging (MRI), are commonly used for the pre-operative positioning of tumors. Nonetheless, tissues can be displaced during surgery, thus making real-time observation and localization impossible. Therefore, there is an urgent clinical need for more accurate, real-time medical imaging techniques to guide precise intraoperative tumor removal to improve therapeutic efficacy.

Recently, surface-enhanced Raman scattering (SERS) imaging has enjoyed extensive applications in the fields of interface and surface science, materials analysis, food safety, environmental monitoring and national security thanks to its high specificity, sensitive detection, remarkable stability, high signal-to-noise ratio and ease of operation. Silver-based hybrid nanoprobes for surface-enhanced Raman scattering (SERS) imaging show their tremendous promise for precise biological detection and mediated phototherapy. The research team led by ZHOU Min from the Zhejiang University Institute of Translational Medicine has engaged in research into this field in recent years and published a series of research articles (Advanced Sciences 2021; Biomaterials 2020; Biomaterials 2021; WIREs Nanomedicine & Nanobiotechnology 2021; Acta Pharmaceutica Sinica B 2018).

Based on their recent study, ZHOU Min et al. published an open-access article entitled “Bioinspired protein corona strategy enhanced biocompatibility of Ag-Hybrid hollow Au nanoshells for surface-enhanced Raman scattering imaging and on-demand activation tumor-phototherapy” in the journal Biomaterials.

In this study, ZHOU Min et al. developed a versatile bioinspired protein corona strategy through assembling bovine serum albumin (BSA) protected Raman tag DTTC-conjugated Ag-hybrid hollow Au nanoshells (hollow AgAu-DTTC-BSA). The silver ion release and reactive oxygen species (ROS) generation are significantly suppressed, thus doing no damage to normal cells and tissues. They can be reactivated on-demand under laser-irradiation at the tumor site. These nanoshells could also produce strong localized surface plasmon resonance for efficient-stable photothermal effect and enhanced SERS activity under laser irradiation, approved by both theoretical and experimental calculations. Furthermore, the biocompatible hollow AgAu-DTTC-BSA could detect both primary tumor tissues and tiny liver metastases (~0.18 mm) in orthotopic/subcutaneous CT26 colon tumor-bearing mice models. Researchers also demonstrate their excellent therapeutic efficacy for colorectal solid neoplasms by accurate SERS imaging-guided photothermal therapy, simultaneously assisted with toxic Ag ion and ROS.

This research suggests that hollow AgAu-DTTC-BSA is a promising imaging assisted photothermal agent for solid tumor theranostics and that it will enhance the likelihood of Ag-based nanoparticles for practical treatment.