Effect of Polyplex Morphology on Cellular Uptake, Intracellular Trafficking, and Transgene Expression

Abstract

Nanoparticle morphology has been shown to affect cellular uptake, but there are few studies investigating the impact of particle shape on biologic drug delivery. Recently, our group synthesized a series of N-(2-hydroxypropyl) methacrylamide (HPMA)-oligolysine brush polymers for nucleic acid delivery that varied in oligolysine peptide length and polymer molecular weight. Interestingly, a 50% longer peptide (K15) transfected very poorly compared to the optimized polymer comprised of K10 peptide despite similar chemical composition and molecular weight. We hypothesized that differences in particle morphology contributed to the differences in plasmid DNA delivery. We found that particles formed with plasmid DNA and a polymer with the longer oligolysine peptide (pHK15) had larger aspect ratios than particles formed with optimized polymer (pHK10). Even though both formulations showed similar percentages of cellular association, particles of a higher aspect ratio were internalized to a lesser extent. Furthermore, the rod-like particles accumulated more in endosomal/lysosomal compartments, leading to delayed nuclear delivery. Other parameters, such as particle surface charge, unpackaging ability, uptake mechanism, intracellular trafficking, nor the presence of heparan sulfate proteoglycans did not significantly differ between the two polymer formulations. These results indicate that, for this system, polyplex morphology primarily impacts nucleic acid delivery efficiency through differences in cellular internalization rates.

Target-specific near-IR induced drug release and photothermal therapy with accumulated Au/Ag hollow nanoshells on pulmonary cancer cell membranes

“…Effective drug delivery by nanocarriers has been intensively investigated using dendrimers [1,2], polymeric micelles [3], liposomes [4,5], carbon-based materials [6e8], magnetic particles [9,10], and noble metal nanoparticles (NPs) [7,11]. Nanocarriers were developed to protect drugs from premature degradation and to enhance drug absorption into specific tissues.…”

Shape control in engineering of polymeric nanoparticles for therapeutic delivery

“…In a separate study using N-(2-hydroxypropyl) methacrylamide (HPMA) as the hydrophilic block, Shi et al showed that the molecular weight of PLL in a HPMA- b -PLL copolymer also effectively changed the shape of complex core micelles formed with plasmid DNA. 124 Nanoparticles formed with copolymers containing longer PLL block exhibited higher aspect ratios than that with shorter PLL blocks, which exhibited more spherical shapes.…”

“…Shi et al , using HPMA- b -PLL copolymers to condense DNA, compared cellular uptake, intracellular trafficking, and transfection efficiency for 25 nm × 74 nm oblong complex core micelles and 18 nm × 102 nm rod-like micelles. 124 The transfection efficiency for the oblong micelles was 42-fold higher than the rod-like micelles with a higher aspect ratio. Mechanistic studies showed that cellular uptake for the more condensed particles was approximately 4-fold higher, whereas the rod-like particles, after internalization, tended to accumulate more in endosomal/lysosomal compartments.…”

Insight into nanoparticle cellular uptake and intracellular targeting

“…Polyplexes derived from copolymers of N -(2-hydroxypropyl)methacrylamide (HPMA) and methacrylamide monomers bearing pendant L-lysine based peptide groups with different numbers of L-lysine repeat units were reported to exhibit an improved nuclear accumulation (plasmid DNA delivery) when the number of L-lysine repeat units was ten (pHK10 and pHK15 stands for polymers with 10 and 15 L-lysine repeat units, Fig. 5) [198]. pHK10 copolymer interacted with the plasmid DNA resulting in the nanoparticles with lower aspect ratio (width ~25 nm and length ~74 nm) when compared to the nanoparticles (width ~18 nm and length ~102 nm) formed by the copolymer pHK15.…”