Figure 5
From: Acid specific dark quencher QC1 pHLIP for multi-spectral optoacoustic diagnoses of breast cancer
MSOT Imaging performance of dark quencher QC1-pHLIP in a murine breast cancer model outperforms fluorescent ICG-pHLIP. Axial tomographic slices through the tumors before and 24 h after tail vein injection demonstrate specific ICG-pHLIP (a) and QC1-pHLIP (b) signals in an orthotopic murine breast cancer model. Tomographic sections of tumors from three different planes (xy, xz and yz) demonstrate targeted distribution of both pHLIPs through the tumor. Scale bar (white) is 2.5 mm, optoacoustic intensity (a.u.) scale is from 4.3 × 101 to 2.8 × 102 (grey scale), CLS score scale is from 7.8 × 101 to 2.1 × 102 (green/cyan). (c) Overall optoacoustic intensities of pre-injected (grey, n = 4) and post injected mice (n = 4) of either ICG-pHLIP (left, green) or QC1-pHLIP (right, cyan) at varying wavelengths (680–900 nm). (d) Representative fluorescent image of excised tumors from ICG-pHLIP injected mice and their corresponding H&E staining. Fluorescent microscopy of the tumors shows membrane insertion and distribution within tumor tissue. No fluorescence was observed in non-injected mice. (e) The accumulation of QC1-pHLIP in the tumor yielded 96% signal enhancement as compared to 35% for ICG-pHLIP.
