title: Self-assembled polyelectrolyte nanoparticles as fluorophore-free contrast agents for multicolor optical imaging.
abstract: In this work, we describe the fabrication of self-assembled polyelectrolyte nanoparticles that provide a multicolor optical imaging modality. Poly(γ-glutamic acid)(γ-PGA) formed self-assembled nanoparticles through electrostatic interactions with two different cationic polymers: poly(L-lysine)(PLL) and chitosan. The self-assembled γ-PGA/PLL and γ-PGA/chitosan nanoparticles were crosslinked by glutaraldehyde. Crosslinking of the ionic self-assembled nanoparticles with glutaraldehyde not only stabilized the nanoparticles but also generated a strong autofluorescence signal. Fluorescent Schiff base bonds (C=N) and double bonds (C=C) were generated simultaneously by crosslinking of the amine moiety of the cationic polyelectrolytes with monomeric glutaraldehyde or with polymeric glutaraldehyde. The unique optical properties of the nanoparticles that resulted from the crosslinking by glutaraldehyde were analyzed using UV/Vis and fluorescence spectroscopy. We observed that the fluorescence intensity of the nanoparticles could be regulated by adjusting the crosslinker concentration and the reaction time. The nanoparticles also exhibited high performance in the labeling and monitoring of therapeutic immune cells (macrophages and dendritic cells). These self-assembled nanoparticles are expected to be a promising multicolor optical imaging contrast agent for the labeling, detection, and monitoring of cells.
authors.affiliation: Center for Chemical analysis, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-600, Korea. sdh2080@krict.re.kr.
authors.forename: Da Hye
authors.initials: DH
authors.lastname: Shin
authors.affiliation: SKKU Advanced Institute of Nanotechnology (SAINT), School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Korea. hmbgo@nate.com.
authors.forename: Min Beom
authors.initials: MB
authors.lastname: Heo
authors.affiliation: SKKU Advanced Institute of Nanotechnology (SAINT), School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Korea. yongtaik@skku.edu.
authors.forename: Yong Taik
authors.initials: YT
authors.lastname: Lim
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival; D048271:Chitosan / Q000737:chemistry*; D003287:Contrast Media / Q000138:chemical synthesis* / Q000737:chemistry; D004573:Electrolytes / Q000138:chemical synthesis* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D061848:Optical Imaging; D010316:Particle Size; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D055672:Static Electricity
chemical_list: D003287:Contrast Media; D004573:Electrolytes; D005456:Fluorescent Dyes; C511775:poly(gamma-glutamic acid); D011107:Polylysine; D011099:Polyglutamic Acid; D048271:Chitosan