Objective To develop albumin-binding indocyanine green (ICG) and assess its potential for near-infrared ?uorescence imaging and intraoperative navigation in lung cancer. Methods ABD-tri was recombinantly expressed by genetic engineering. Its albumin-binding capability was determined using size-exclusion chromatography, and its albumin-dependent binding to lung cancer cells was evaluated by flow cytometry. ICG was conjugated to ABD-tri to generate the fluorescent probe ABD-tri-ICG. The potential of ABD-tri-ICG for near-infrared ?uorescence imaging and imaging-guided tumor resection was evaluated in mice bearing subcutaneous tumor grafts of lung cancer. Results ABD-tri was highly expressed in Escherichia coli (E. coli) and was purified to homogeneity via a simple affinity chromatography. ABD-tri bound both human and murine serum albumin, contributing to its binding to lung cancer cells. ICG was effectively conjugated to ABD-tri to produce the fluorescence probe ABD-tri-ICG after mixing and incubation at room temperature for 1 h. In mice bearing lung cancer tumor grafts, intravenously injected ABD-tri-ICG enabled clear visualization of tumors with diameters ranging from 5 to 7 mm within 0.5-24 h post-injection. The tumor grafts were resected under the guidance of by ABD-tri-ICG-mediated near-infrared ?uorescence imaging. ConclusionIntravenous injection of ABD-tri-ICG allows rapid and sustained visualization of lung cancer tumor grafts and enables intraoperative navigation in mice, warranting further evaluation on the clinical translation of ABD-tri-ICG.
ObjectiveTo prepare platelet-derived growth factor receptor β (PDGFRβ)-targeted near-infrared molecular probe and evaluate its potential in optical molecular imaging of lung cancer.MethodsPDGFRβ-specific affibody Z-tri was recombinantly expressed in Escherichia coli (E. coli) and purified using affinity chromatography. In vitro cell-binding of Z-tri was analyzed by flow cytometry. Cellular distribution of Z-tri in tumor grafts was determined by protein-tracing. The molecular probe CF750-Z-tri was prepared by conjugating near-infrared fluorescent dye CF750 to Z-tri. The optical images of xenografts of lung cancer were obtained by using CF750-Z-tri combined with optical imaging system.ResultsPDGFRβ-specific affibody Z-tri was highly expressed in E. coli and purified to homogeneity. Z-tri could bind PDGFRβ-positive cells but not PDGFRβ-negative cells cultured in vitro. In the tumor xenografts of human lung cancer, intravenously injected Z-tri was predominantly distributed on cells overexpressing PDGFRβ. The near infrared fluorescent dye CF750 was efficiently conjugated to Z-tri. Optical images with high contrast of lung cancer xenografts were produced by using the near-infrared fluorescent probe CF750-Z-tri combined with optical imaging system.ConclusionThe near-infrared fluorescent probe CF750-Z-tri can be used for optical imaging of human lung cancer, which takes great potential in optical imaging-guided surgery of lung cancer.