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Critical Length of PEG Grafts on lPEI/DNA Nanoparticles for Efficient in Vivo Delivery.

Williford JM, Archang MM, Minn I, Ren Y, Wo M, Vandermark J, Fisher PB, Pomper MG, Mao HQ - ACS Biomater Sci Eng (2016)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.


Related in: MedlinePlus

lPEI-g-PEG/DNA nanoparticles with short PEG5Hgrafts show reduced toxicity in vivo. (A, B) Liver enzyme activitiesanalyzed by measuring serum AST (A) and ALT (B) levels in Balb/c miceat 48 h after systemic injection of lPEI-g-PEG5H/DNAnanoparticles prepared with or without RYVVLPR cell adhesion peptideand in vivo jetPEI/DNA nanoparticles. Green lines show the normalranges of AST and ALT enzymes in rats. Each bar represents mean ±standard deviation (n = 4 per group). (C–E)H&E staining of liver tissue comparing untreated controls to thosetreated with jetPEI/DNA control nanoparticles and RYVVLPR-conjugatedlPEI-g-PEG5H/DNA nanoparticles. Scale bar represents100 μm.
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fig8: lPEI-g-PEG/DNA nanoparticles with short PEG5Hgrafts show reduced toxicity in vivo. (A, B) Liver enzyme activitiesanalyzed by measuring serum AST (A) and ALT (B) levels in Balb/c miceat 48 h after systemic injection of lPEI-g-PEG5H/DNAnanoparticles prepared with or without RYVVLPR cell adhesion peptideand in vivo jetPEI/DNA nanoparticles. Green lines show the normalranges of AST and ALT enzymes in rats. Each bar represents mean ±standard deviation (n = 4 per group). (C–E)H&E staining of liver tissue comparing untreated controls to thosetreated with jetPEI/DNA control nanoparticles and RYVVLPR-conjugatedlPEI-g-PEG5H/DNA nanoparticles. Scale bar represents100 μm.

Mentions: In addition to the transfection efficiencyimprovements, RYVVLPR-conjugated nanoparticles also reduce the toxicityresponse to nanoparticle treatment in Balb/c mice. We first measuredserum levels of aspartate aminotransferase (AST) and alanine aminotransferase(ALT), two common markers of liver function, because a majority ofthe nanoparticle dose accumulates in the liver. Two days after nanoparticleinjection, AST and ALT levels, 900 and 260 U/mL, were significantlyhigher than the normal range when treated with jetPEI/DNA nanoparticles.RYVVLPR-conjugated nanoparticles, on the other hand, averaged 200and 120 U/mL for AST and ALT, respectively (Figure 8A, B). We also evaluated tissue morphologicalchanges by H&E staining. In the liver, a mild degree of monocyteaccumulation was observed near portal and central veins in mice receivedin vivo jetPEI/DNA nanoparticles, which correlated well with the elevatedALT and AST levels. Monocyte accumulation was not observed in eitherlPEI-g-PEG/DNA nanoparticle-treated mice or untreatedcontrol (Figure 8C).


Critical Length of PEG Grafts on lPEI/DNA Nanoparticles for Efficient in Vivo Delivery.

Williford JM, Archang MM, Minn I, Ren Y, Wo M, Vandermark J, Fisher PB, Pomper MG, Mao HQ - ACS Biomater Sci Eng (2016)

lPEI-g-PEG/DNA nanoparticles with short PEG5Hgrafts show reduced toxicity in vivo. (A, B) Liver enzyme activitiesanalyzed by measuring serum AST (A) and ALT (B) levels in Balb/c miceat 48 h after systemic injection of lPEI-g-PEG5H/DNAnanoparticles prepared with or without RYVVLPR cell adhesion peptideand in vivo jetPEI/DNA nanoparticles. Green lines show the normalranges of AST and ALT enzymes in rats. Each bar represents mean ±standard deviation (n = 4 per group). (C–E)H&E staining of liver tissue comparing untreated controls to thosetreated with jetPEI/DNA control nanoparticles and RYVVLPR-conjugatedlPEI-g-PEG5H/DNA nanoparticles. Scale bar represents100 μm.
© Copyright Policy - editor-choice
Related In: Results  -  Collection

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fig8: lPEI-g-PEG/DNA nanoparticles with short PEG5Hgrafts show reduced toxicity in vivo. (A, B) Liver enzyme activitiesanalyzed by measuring serum AST (A) and ALT (B) levels in Balb/c miceat 48 h after systemic injection of lPEI-g-PEG5H/DNAnanoparticles prepared with or without RYVVLPR cell adhesion peptideand in vivo jetPEI/DNA nanoparticles. Green lines show the normalranges of AST and ALT enzymes in rats. Each bar represents mean ±standard deviation (n = 4 per group). (C–E)H&E staining of liver tissue comparing untreated controls to thosetreated with jetPEI/DNA control nanoparticles and RYVVLPR-conjugatedlPEI-g-PEG5H/DNA nanoparticles. Scale bar represents100 μm.
Mentions: In addition to the transfection efficiencyimprovements, RYVVLPR-conjugated nanoparticles also reduce the toxicityresponse to nanoparticle treatment in Balb/c mice. We first measuredserum levels of aspartate aminotransferase (AST) and alanine aminotransferase(ALT), two common markers of liver function, because a majority ofthe nanoparticle dose accumulates in the liver. Two days after nanoparticleinjection, AST and ALT levels, 900 and 260 U/mL, were significantlyhigher than the normal range when treated with jetPEI/DNA nanoparticles.RYVVLPR-conjugated nanoparticles, on the other hand, averaged 200and 120 U/mL for AST and ALT, respectively (Figure 8A, B). We also evaluated tissue morphologicalchanges by H&E staining. In the liver, a mild degree of monocyteaccumulation was observed near portal and central veins in mice receivedin vivo jetPEI/DNA nanoparticles, which correlated well with the elevatedALT and AST levels. Monocyte accumulation was not observed in eitherlPEI-g-PEG/DNA nanoparticle-treated mice or untreatedcontrol (Figure 8C).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.


Related in: MedlinePlus