Table 1 Summary of the imaging probes for deep tissue imaging
From: Recent advances in optical imaging through deep tissue: imaging probes and techniques
Strategy | Advantages/obstacles | Material | In vivo application | Ref. |
|---|---|---|---|---|
NIR-II | Deeper penetration depth compared to another wavelength region/Hard to develop hydrophilic NIR-II dyes. | Tat peptide-modified Pb/S quantum dot | Mesenchymal stem cell labelling and subcutaneous injection (mice). | [10] |
Heptamethine-cyanine-based NIR-II fluorophore | Intravenous injection and tumor imaging (mice). | [11] | ||
Metal nanotube-type phosphorescence probe | Subcutaneous injection and tumor imaging (mice) | [12] | ||
Bioluminescence | No excitation/Need luciferase protein with low in vivo stability, Time-dependent change of imaging signals. | Nano-luciferase complex and diphenyltetrazine pair | Intravenous injection of plasmid and intraperitoneal injection of diphenyltetrazine substrate for red-shifted bioluminescence (mice). | [13] |
Red fluorescence protein-luciferase fusion protein and biothiol-responsive coelenterazine | Subcutaneous injection of biothiol-responsive coelenterazine and tumor imaging (mice). | [14] | ||
H-ferritin nanocage-luciferin conjugate | Intravenous injection of nanocage and tumor imaging (mice). | [15] | ||
Chemiluminescence | No excitation/Time-dependent change of imaging signals. | Granzyme B-responsive phenoxydioxetane probe | Intratumoral injection of probe and imaging of NK cell effect in tumor (mice). | [16] |
Chemical conjugates of three components (NIRF dye, chemiluminescence dye, and cyclodextrin derivative). | Intravenous injection of the probe for dual imaging of drug-induced acute kidney injury (mice). | [17] | ||
Tetraphenylethylene-phthalhydrazid-based nanoparticle | Intravenous injection of probe and singlet oxygen imaging in arthritis model (rat). | [18] | ||
After glow | No excitation/Time-dependent change of imaging signals. Relatively short imaging time. | ZnSn2O4:Cr,Eu nanoparticle | Intravenous injection of the nanoparticle and tumor imaging (mice). | [19] |
Semiconducting polymer (phenylenevinylene) nanoparticle | Intravenous injection of the nanoparticle and lymph node/ tumor imaging (mice). | [20] | ||
Nanoparticle of three components (afterglow initiator, substrate, and semiconducting polymer). | Intravenous injection of the nanoparticle and tumor imaging (mice). | [21] |