We report on the design of glycosylated nanogels via core-cross-linking of amphiphilic non-watersoluble block copolymers composed of an acetylated glycosylated block and a pentafluorophenyl (PFP) activated ester block prepared by RAFT polymerization. Self-assembly, pH-sensitive corecross-linking and removal of remaining PFP esters and protecting groups is achieved in one-pot yielding fully hydrated sub-100 nm nanogels. Using cell subsets that exhibit high and low expression of the mannose receptor under conditions that suppress active endocytosis, we show that mannosylated but not galactosylated nanogels can efficiently target the mannose receptor (MR) that is expressed on the cell surface of primary dendritic cells (DCs). These nanogels hold promise for immunological applications involving DCs and macrophage subsets.

Low birth weight is associated with both short term problems and the fetal programming of adult onset diseases, including an increased risk of obesity, diabetes and cardiovascular disease. Placental insufficiency leading to intrauterine growth restriction (IUGR) contributes to the prevalence of diseases with developmental origins. Currently there are no therapies for IUGR or placental insufficiency. To address this and move towards development of an in utero therapy, we employ a nanostructure delivery system complexed with the IGF-1 gene to treat the placenta. IGF-1 is a growth factor critical to achieving appropriate placental and fetal growth. Delivery of genes to a model of human trophoblast and mouse placenta was achieved using a diblock copolymer (pHPMA-b-pDMAEMA) complexed to hIGF-1 plasmid DNA under the control of trophoblast-specific promoters (Cyp19a or PLAC1). Transfection efficiency of pEGFP-C1-containing nanocarriers in BeWo cells and non-trophoblast cells was visually assessed via fluorescence microscopy. In vivo transfection and functionality was assessed by direct placental-injection into a mouse model of IUGR. Complexes formed using pHPMA-b-pDMAEMA and CYP19a-923 or PLAC1-modified plasmids induce trophoblast-selective transgene expression in vitro, and placental injection of PLAC1-hIGF-1 produces measurable RNA expression and alleviates IUGR in our mouse model, consequently representing innovative building blocks towards human placental gene therapies.

N-alkyl urea peptoid oligomers containing glucose or mannose have been synthesized and characterized. The oligomers were subsequently polymerized using a step-growth polymerization with hexamethylene diisocyanate. Equal moles of both monomers were used to guarantee high-molecular weight polymers. The polymers were characterized by gel permeation chromatography, nuclear magnetic resonance, and Fourier-transform infrared spectroscopy, and contact angle measurements of solvent cast thin films. Sulfation of the final polymers was achieved using a SO 3 =pyridine complex in pyridine to afford the heparin biomimetics. The average degree of sulfation was calculated to be 3.5 sulfates per saccharide as measured by elemental analysis.

The synthesis of a glycosaminoglycan polymer mimetic is reported. An isopropylidene protected glucose methacrylate monomer was copolymerized under reversible addition fragmentation chain transfer polymerization control with an azido-containing comonomer to a molecular weight of 29 000 g mol −1 with polydispersity of 1.21. The comonomer ratio was determined to be 15:1 based on 1 H NMR spectroscopy. This copolymer was coupled to sugar-functionalized N-alkyl-N,N-linked urea oligomers using a copper catalyzed alkyne/azide cycloaddition reaction. The reaction efficiency was 100% as monitored by 1 H NMR spectroscopy. The isopropylidene protecting groups on the polymer and N-alkyl-N,N-linked urea oligomers were removed using acid hydrolysis to give the final polysaccharide mimetic. It is expected that these polymers will have applications in a variety of future therapeutic applications.

Background: Nonviral polymeric delivery systems are explored to enhance clinical development of nucleic acids as therapeutic entities for effective management of debilitating conditions such as cancer. This study was to compare safety and efficacy of quaternary amine-containing methacrylate polymer Eudragit ® RL PO (ERL) and poly[N-(2-hydroxypropyl)methacrylamide]-poly(N,N-dimethylaminoethyl methacrylate) copolymer (pHPMA-b-pDMAEMA), which contains secondary and tertiary amines, as effective gene carriers. Methods: Polyplexes of pAcGFP1-C1 with ERL or pHPMA-b-pDMAEMA were fabricated at different N/P ratios. Formation of DNA/catiomer nanostructures was monitored by ethidium bromide intercalation and agarose gel retardation. Particle size, zeta potential and cytotoxicity of different polyplexes were characterized. Transfection efficiency in presence and absence of serum was assessed using confocal microscopy. Results: pHPMA-b-pDMAEMA demonstrated at least a 10-fold greater DNA condensation capacity per weight unit than ERL. However, DNA intercalation with pHPMA-b-pDMAEMA was reduced in presence of serum-free cell culture media, whereas polyplex formation with ERL was equivalent in phosphate-buffered saline, pH 7.4 and serum-free cell culture media. Cellular safety of HeLa cells was not compromised by polyplexes fabricated with either polymer up to N/P=4. However, ERL alone was more toxic. In absence of serum, pHPMA-b-pDMAEMA polyplexes at N/P=4 induced equivalent transgene expression as control TurboFect™ polyplexes. In contrast, ERL-containing nanoassemblies failed to produce measurable transgene expression. Inclusion of serum significantly decreased transfection efficiency of pHPMA-b-pDMAEMA-containing polyplexes by ~30% at N/P=4 and ~50% at N/P=2. Conclusion: Polyplexes fabricated with secondary and tertiary amine-containing pHPMA-b-pDMAEMA copolymer represent more effective gene delivery systems than nanoassemblies composed of quaternary amine-containing ERL and should be further explored for clinical applications.