Protective copolymers for nonviral gene vectors: synthesis, vector characterization and application in gene delivery

Abstract

Uncontrolled interactions of gene vectors and drug carriers in and with an in vivo environment pose serious limitations to their applicability. In order to reduce such interactions we have designed, synthesized and applied novel copolymers of poly(ethylene glycol) and reactive linkers which are derivatized with anionic peptides after copolymerization. The anionic copolymer derivatives are used to coat positively charged nonviral gene vectors by electrostatic interactions. The copolymer coat confers to polyelectrolyte colloids of DNA and polycations steric stabilization in their minimal size and prevents salt-and serum albumin-induced aggregation.

Magnetofection: enhancing and targeting gene delivery by magnetic force in vitro and in vivo

“…Subsequently, the cells were washed once with fresh medium, grown for 24 or 48 h and subjected to reporter gene assays as described elsewhere. 24,25 Nonviral magnetofection Plasmids p55pCMV-IVS-luc+, coding for the firefly luciferase, and pCMV-ß-gal were kindly provided by Andrew Baker (Bayer, USA) and by Walter Schmidt (Intercell, Vienna, Austria), respectively. Plasmids were purified by cesium chloride gradient.…”

The Magnetofection Method: Using Magnetic Force to Enhance Gene Delivery

“…During this incubation time, cells in triplicate wells each were washed with PBS and lysed for luciferase assay after 1, 2, 4, and 8 hours of incubation and then again after 24 and 48 hours. The luciferase assay was performed as described (Finsinger et al, 2000). The figure shows the early onset of detectable reporter gene expression upon magnetofection which peaked after 24 hours and which was consistently higher than the one achieved with standard transfection (enhancement of 9-to 18-fold after onset of reporter gene expression in the standard wells).…”

“…These complexes have been shown by numerous researchers to be particles of nanometric size or aggregates thereof. Often, toroids and rods are observed for polyplexes and less regular structures for lipoplexes, sometimes extending into the micrometer size range (an example of such structures is shown in Finsinger et al, 2000). As (strept)avidin or antibody-coated magnetic particles are expensive to manufacture, we decided to use the simplest way of linkage, physical interaction, which not only is the cheapest way but also highly effective and fully compatible with the cellular processing of gene vectors.…”

“…To the 4 hour plates 100 µl/well of fresh medium containing 20% FCS (+ pen/strep) were added without a washing step. The luciferase assay was carried out as described (Finsinger et al, 2000) after 24 hours. The Figure shows that the transfection efficiency decreased at higher magnetic particle doses probably due to toxicity.…”

Targeted delivery of RNA-cleaving DNA enzyme (DNAzyme) to tumor tissue by transferrin-modified, cyclodextrin-based particles

“…The CDPs are capable of providing the in vitro delivery of plasmids in the presence of serum. [11][12][13][14][15] The CDPs demonstrate low toxicity in vitro (for βCDP6, a CDP containing 6 methylene units between charges, IC 50 = 1.1 mM to BHK-21 cells) and in vivo (for βCDP6, LD 40 = 200 mg/kg in mice) and may be suitable for oligonucleotide delivery due to their low degree of polymerization (short polycations are known to minimize complement activation 7 ). Polyplexes formed using CDPs can be modified to impart stability in biological fluids and cell targeting specificity by surface decoration with adamantanebased modifiers (Figs.…”