Multifunctional theranostic nanoplatform based on HER2-specific liposomes loaded with IR783 for simultaneous PTT/PDT therapy and optical bioimaging.

We propose a new multifunctional nanoplatform for intravital optical bioimaging and combined photodynamic and photothermal therapy of HER2-positive cancers, using single-wavelength laser irradiation. The system consists of IR783-loaded liposomes functionalized with a HER2-targeting designed ankyrin repeat protein (DARPin_9-29), genetically fused to an albumin-binding domain (ABD). The bifunctional module DARP-ABD on the liposome surface provides HER2-specific tumor targeting with a high tumor-to-background ratio, enabling effective tumor bioimaging. IR783 encapsulated in liposomes retains its photothermal properties and ability to generate ROS when exposed to near-infrared irradiation. Administration of DARP-ABD-Lip(IR783) followed by laser irradiation resulted in significant tumor growth inhibition (TGI of 70.6% by day 10), which progressed to a remarkable 91.5% TGI by the end of the monitoring period.