Croconaine-based nanoparticles enable efficient optoacoustic imaging of murine brain tumors

Contrast enhancement in optoacoustic (photoacoustic) imaging can be achieved with agents that exhibit high absorption cross-sections, high photostability, low quantum yield, low toxicity, and preferential bio-distribution and clearance profiles. Based on advantageous photophysical properties of croconaine dyes, we explored croconaine-based nanoparticles (CR780RGD-NPs) as highly efficient contrast agents for targeted optoacoustic imaging of challenging preclinical tumor targets. Initial characterization of the CR780 dye was followed by modifications using polyethylene glycol and the cancer-targeting c(RGDyC) peptide, resulting in self-assembled ultrasmall particles with long circulation time and active tumor targeting. Preferential bio-distribution was demonstrated in orthotopic mouse brain tumor models by multispectral optoacoustic tomography (MSOT) imaging and histological analysis. Our findings showcase particle accumulation in brain tumors with sustainable strong optoacoustic signals and minimal toxic side effects. This work points to CR780RGD-NPs as a promising optoacoustic contrast agent for potential use in the diagnosis and image-guided resection of brain tumors

Bioengineered bacterial vesicles as biological nano-heaters for optoacoustic imaging

Bacterial outer membrane vesicles (OMVs) are increasingly used as carriers for drug delivery. Here the authors encapsulate biopolymer melanin into OMVs, extending their use to optoacoustic imaging both in vitro and in vivo, and demonstrate the potential of this tool for photothermal therapy applications

Bacterial outer membrane vesicles as cationic dye carriers for optoacoustics-guided phototherapy of cancer

Abstract Background Cationic dyes are widely used as biomarkers for optical imaging. However, most of these are hydrophobic and cannot be employed in vivo without chemical conjugation or modification. Herein, we report for the first time the use of bacterial outer membrane vesicles (OMVs) as nanocarriers of cationic dyes for cancer theranostics. Results We demonstrate that cationic dyes (IR780, Cy7, and Cy7.5) form stable complexes with negatively charged bacterial-OMVs, improving the dyes’ in vivo circulation and optoacoustic properties. Such OMV-Dye complexes are biodegradable and safe for in vivo applications. Importantly, this method of cationic dye loading is faster and easier than synthetic chemistry approaches, and the efficient tumor accumulation of OMV-Dyes enables sensitive tumor detection using optoacoustic technology. As a proof-of-concept, we generated OMV-IR780 for optoacoustics-guided in vivo tumor phototherapy in a mouse model. Conclusions Our results demonstrate cationic dye-bound OMVs as promising novel nanoagents for tumor theranostics

Croconaine-based nanoparticles enable efficient optoacoustic imaging of murine brain tumors

Contrast enhancement in optoacoustic (photoacoustic) imaging can be achieved with agents that exhibit high absorption cross-sections, high photostability, low quantum yield, low toxicity, and preferential bio-distribution and clearance profiles. Based on advantageous photophysical properties of croconaine dyes, we explored croconaine-based nanoparticles (CR780RGD-NPs) as highly efficient contrast agents for targeted optoacoustic imaging of challenging preclinical tumor targets. Initial characterization of the CR780 dye was followed by modifications using polyethylene glycol and the cancer-targeting c(RGDyC) peptide, resulting in self-assembled ultrasmall particles with long circulation time and active tumor targeting. Preferential bio-distribution was demonstrated in orthotopic mouse brain tumor models by multispectral optoacoustic tomography (MSOT) imaging and histological analysis. Our findings showcase particle accumulation in brain tumors with sustainable strong optoacoustic signals and minimal toxic side effects. This work points to CR780RGD-NPs as a promising optoacoustic contrast agent for potential use in the diagnosis and image-guided resection of brain tumors