title: Nano-carrier for gene delivery and bioimaging based on carbon dots with PEI-passivation enhanced fluorescence.
abstract: Polyethylenimine (PEI) functionalized carbon dots (CD-PEI) were fabricated by one-step microwave assisted pyrolysis of glycerol and branched PEI25k mixture where the formation of carbon nanoparticles and the surface passivation were accomplished simultaneously. In this hybrid C-dot, PEI molecule played two key roles in the system - as a nitrogen-rich compound to passivate surface to enhance the fluorescence and as a polyelectrolyte to condense DNA. This CD-PEI was shown to be water soluble and emit stable bright multicolor fluorescence relying on excitation wavelength. The DNA condensation capability and cytotoxicity of CD-PEI could be regulated by pyrolysis time possibly due to the somewhat destruction of PEI during the formation of carbon dots. CD-PEI obtained at an appropriate pyrolysis time exhibited lower toxicity, higher or comparable gene expression of plasmid DNA in COS-7 cells and HepG2 cells relative to control PEI25k. Intriguingly, the CD-PEIs internalized into cells displayed tunable fluorescent emission under varying excitation wavelength, suggesting the potential application of CD-PEI in gene delivery and bioimaging.
authors.affiliation: School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin 300072, PR China.
authors.forename: Changjun
authors.initials: C
authors.lastname: Liu
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Xinyun
authors.initials: X
authors.lastname: Zhai
authors.forename: Feng
authors.initials: F
authors.lastname: Tian
authors.forename: Wenchen
authors.initials: W
authors.lastname: Li
authors.forename: Jianhai
authors.initials: J
authors.lastname: Yang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Hongbo
authors.initials: H
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Wenguang
authors.initials: W
authors.lastname: Liu
mesh_terms: D000818:Animals; D019556:COS Cells; D002244:Carbon / Q000737:chemistry* / Q000633:toxicity; D016923:Cell Death / Q000187:drug effects; D002522:Chlorocebus aethiops; D004247:DNA / Q000378:metabolism; D003952:Diagnostic Imaging / Q000379:methods*; D004337:Drug Carriers / Q000737:chemistry*; D004587:Electrophoresis, Agar Gel; D018014:Gene Transfer Techniques; D056945:Hep G2 Cells; D006801:Humans; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D010957:Plasmids / Q000378:metabolism; D011094:Polyethyleneimine / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D014162:Transfection
chemical_list: D004337:Drug Carriers; D002244:Carbon; D011094:Polyethyleneimine; D004247:DNA