Black phosphorus (BP) nanostructures have been receiving enormous attention in diverse bioapplications owing to their unique physicochemical properties. However, it is still challenging to investigate their blood circulation, biodistribution, and pharmacokinetics after administration due to the difficulty in quantifying them. Here, we report the quantification of blood circulation, biodistribution, and pharmacokinetics of dextran-modified BP nanoparticles (i.e., BP-DEX NPs) in balb/c mice through the highly sensitive noninvasive photoacoustic (PA) imaging and single-emission computed tomography/computed tomography (SPECT/CT) imaging. We first prepare water-soluble and biocompatible small BP-DEX NPs and label them with radioisotopes 99mTc. We then quantify their half-lives of distribution and elimination phases to be 0.2 and 9.5 h by counting the γ-emissions in the blood of mice administrated with BP-DEX NPs. We also show the dynamic variation of BP-DEX NPs in the tumor, liver, spleen, and kidney through in vivo PA imaging and illustrate the accumulation of nanoparticles in major organs by SPECT/CT imaging, which follows an order of spleen > liver > lung > kidney. Our work demonstrates the renal clearance and hepatobiliary excretion of BP-DEX NPs, which could be potentially translated for clinical in vivo imaging and therapy of cancer.
Keywords: SPECT/CT imaging; black phosphorus; blood circulation; pharmacokinetics; photoacoustic imaging.