title: Effect of polyethylene glycol coatings on uptake of indocyanine green loaded nanocapsules by human spleen macrophages in vitro.
abstract: Near-infrared (NIR) optically active nanoparticles are promising exogenous chromophores for applications in medical imaging and phototherapy. Since nanoparticles can be rapidly eliminated from the body by cells of the reticuloendothelial system, a thriving strategy to increase their blood circulation time is through surface modification with polyethylene glycol (PEG). We constructed polymeric nanocapsules loaded with indocyanine green (ICG), an FDA-approved NIR dye, and coated with aldehyde-terminated PEG. Using optical absorbance spectroscopy and flow cytometry, we investigated the effect of PEG coating and molecular weight (MW) of PEG [5000 and 30,000 Daltons (Da)] on the phagocytic content of human spleen macrophages incubated with ICG-containing nanocapsules (ICG-NCs) between 15 to 360 min. Our results indicate that surface coating with PEG is an effective method to reduce the phagocytic content of ICG-NCs within macrophages for at least up to 360 min of incubation time. Coating the surface of ICG-NCs with the low MW PEG results in lower phagocytic content of ICG-NCs within macrophages for at least up to 60 min of incubation time as compared to ICG-NCs coated with the high MW PEG. Surface coating of ICG-NCs with PEG is a promising approach to prolong vasculature circulation time of ICG for NIR imaging and phototherapeutic applications.
authors.affiliation: Department of Bioengineering, University of California, Riverside, California 92521, USA.
authors.forename: Baharak
authors.initials: B
authors.lastname: Bahmani
authors.forename: Sharad
authors.initials: S
authors.lastname: Gupta
authors.forename: Srigokul
authors.initials: S
authors.lastname: Upadhyayula
authors.forename: Valentine I
authors.initials: VI
authors.lastname: Vullev
authors.forename: Bahman
authors.initials: B
authors.lastname: Anvari
mesh_terms: D002460:Cell Line; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis*; D003287:Contrast Media / Q000138:chemical synthesis; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation; D007208:Indocyanine Green / Q000493:pharmacokinetics; D008264:Macrophages / Q000166:cytology* / Q000378:metabolism; D008856:Microscopy, Fluorescence / Q000295:instrumentation*; D015336:Molecular Probe Techniques / Q000295:instrumentation; D053769:Nanocapsules / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D013154:Spleen / Q000166:cytology* / Q000378:metabolism
chemical_list: D020099:Coated Materials, Biocompatible; D003287:Contrast Media; D053769:Nanocapsules; D011092:Polyethylene Glycols; D007208:Indocyanine Green