title: Critical Length of PEG Grafts on lPEI/DNA Nanoparticles for Efficient in Vivo Delivery.
abstract: Nanoparticle-mediated gene delivery is a promising alternative to viral methods; however, its use in vivo, particularly following systemic injection, has suffered from poor delivery efficiency. Although PEGylation of nanoparticles has been successfully demonstrated as a strategy to enhance colloidal stability, its success in improving delivery efficiency has been limited, largely due to reduced cell binding and uptake, leading to poor transfection efficiency. Here we identified an optimized PEGylation scheme for DNA micellar nanoparticles that delivers balanced colloidal stability and transfection activity. Using linear polyethylenimine (lPEI)-g-PEG as a carrier, we characterized the effect of graft length and density of polyethylene glycol (PEG) on nanoparticle assembly, micelle stability, and gene delivery efficiency. Through variation of PEG grafting degree, lPEI with short PEG grafts (molecular weight, MW 500-700 Da) generated micellar nanoparticles with various shapes including spherical, rodlike, and wormlike nanoparticles. DNA micellar nanoparticles prepared with short PEG grafts showed comparable colloidal stability in salt and serum-containing media to those prepared with longer PEG grafts (MW 2 kDa). Corresponding to this trend, nanoparticles prepared with short PEG grafts displayed significantly higher in vitro transfection efficiency compared to those with longer PEG grafts. More importantly, short PEG grafts permitted marked increase in transfection efficiency following ligand conjugation to the PEG terminal in metastatic prostate cancer-bearing mice. This study identifies that lPEI-g-PEG with short PEG grafts (MW 500-700 Da) is the most effective to ensure shape control and deliver high colloidal stability, transfection activity, and ligand effect for DNA nanoparticles in vitro and in vivo following intravenous administration.
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, Maryland 21205, United States; Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States.
authors.forename: John-Michael
authors.initials: JM
authors.lastname: Williford
authors.affiliation: Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States; Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States.
authors.forename: Maani M
authors.initials: MM
authors.lastname: Archang
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins Medical Institutions , 601 N. Caroline Street, Baltimore, Maryland 21287, United States.
authors.forename: Il
authors.initials: I
authors.lastname: Minn
authors.affiliation: Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States; Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States.
authors.forename: Yong
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States; Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Wo
authors.affiliation: Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States; Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States.
authors.forename: John
authors.initials: J
authors.lastname: Vandermark
authors.affiliation: Department of Human and Molecular Genetics, Virginia Commonwealth University, 1101 East Marshall Street, Richmond, Virginia 23298, United States; VCU Institute of Molecular Medicine, Virginia Commonwealth University, 1220 East Broad Street, Richmond, Virginia 23298, United States; VCU Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Fisher
authors.affiliation: Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States; Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States; Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins Medical Institutions, 601 N. Caroline Street, Baltimore, Maryland 21287, United States.
authors.forename: Martin G
authors.initials: MG
authors.lastname: Pomper
authors.affiliation: Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States; Institute for NanoBioTechnology and Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States; Translational Tissue Engineering Center and Whitaker Biomedical Engineering Institute, Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, Maryland 21287, United States.
authors.forename: Hai-Quan
authors.initials: HQ
authors.lastname: Mao
keywords: DNA; nanomedicine; nonviral; shape; tumor-specific promoter