Ag5IO6: novel antibiofilm activity of a silver compound with application to medical devices.

This work explores the unique antibiofilm activity of pentasilver hexaoxoiodate (Ag(5)IO(6)). To test this activity, wound dressings were impregnated with Ag(5)IO(6) and compared with various commercially available silver-containing dressings, as well as dressings containing chlorhexidine, iodine and polyhexamethylene biguanide (PHMB). The materials were tested against Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans for their ability to prevent micro-organism adherence, eliminate planktonic micro-organisms and disrupt/eliminate mature biofilms generated using the MBEC™ assay within 24 h of microbial exposure.

Dispersions of nanocrystalline cellulose in aqueous polymer solutions: structure formation of colloidal rods.

The steady-state shear and linear viscoelastic deformations of semidilute suspensions of rod-shaped nanocrystalline cellulose (NCC) particles in 1.0% hydroxyethyl cellulose and carboxymethyl cellulose solutions were investigated. Addition of NCC at the onset of semidilute suspension concentration significantly altered the rheological and linear viscoelastic properties of semidilute polymer solutions.

Bisphosphonate-decorated lipid nanoparticles designed as drug carriers for bone diseases.

A conjugate of distearoylphosphoethanolamine-polyethylene glycol with 2-(3-mercaptopropylsulfanyl)-ethyl-1,1-bisphosphonic acid (thiolBP) was synthesized and incorporated into micelles and liposomes to create mineral-binding nanocarriers for therapeutic agents. The micelles and liposomes were used to encapsulate the anticancer drug doxorubicin (DOX) and a model protein lysozyme (LYZ) by using lipid film hydration (LFH) and reverse-phase evaporation vesicle (REV) methods. The results indicated that the micelles and LFH-derived liposomes were better at DOX loading than the REV-derived liposomes, while the REV method was preferable for encapsulating LYZ.

Relationship between the extent of lipid substitution on poly(L-lysine) and the DNA delivery efficiency.

Poly(L-lysine) (PLL) is a commonly used polymer for nonviral gene delivery. However, the polymer exhibits significant toxicity and is not very effective for transgene expression. To enhance the gene delivery efficiency of the polymer, we imparted an amphiphilic property to PLL by substituting approximately 10% of epsilon-NH2 with several endogenous lipids of variable chain lengths (lipid carbon chain ranging from 8 to 18).

Formulation and delivery of siRNA by oleic acid and stearic acid modified polyethylenimine.

This study was conducted to formulate a nonviral delivery system for the delivery of small interfering RNA (siRNA) to B16 melanoma cells in vitro. For this purpose, oleic and stearic acid modified derivatives of branched polyethylenimine (PEI) were prepared and evaluated. The hydrophobically modified polymers increased siRNA condensation up to 3 folds as compared to the parent PEI.

Further investigation of lipid-substituted poly(L-Lysine) polymers for transfection of human skin fibroblasts.

Enabling gene expression in skin fibroblasts using safe, nonviral gene delivery has the potential to stimulate wound healing and aid in skin tissue engineering efforts. In this study, several lipid-substituted poly(L-Lysines) (PLL) were investigated for their ability to deliver a plasmid DNA (pEGFP) to human skin fibroblasts. While native and lipid-substituted PLLs showed complete complexation with pEGFP, polymers with higher lipid substitution were more resilient to dissociation after heparin treatment.

A comparative evaluation of poly-L-lysine-palmitic acid and Lipofectamine 2000 for plasmid delivery to bone marrow stromal cells.

The current study compared the effectiveness of an amphiphilic biomaterial poly(L-lysine)-palmitic acid (PLL-PA), and the lipid-based transfection agent Lipofectamine 2000 for plasmid delivery to bone marrow stromal cells (BMSC). We investigated the utility of the carriers to deliver a plasmid containing enhanced green fluorescent protein (pEGFP) to BMSC in vitro. Confocal microscopy was used to investigate the intracellular trafficking of pEGFP/carrier complexes.

Palmitic acid substitution on cationic polymers for effective delivery of plasmid DNA to bone marrow stromal cells.

Nonviral gene carriers are actively explored in gene therapy due to safety concerns of the viral carriers. To design effective gene carriers for modification of bone marrow stromal cells (BMSC), an important cell phenotype for clinical application of gene therapy, cationic polymers polyethyleneimine (PEI), and poly-L-Lysine (PLL) were substituted with palmitic acid (PA) via amide linkages. Depending on the reaction conditions, PEI and PLL was substituted with 2.

Palmitic acid-modified poly-L-lysine for non-viral delivery of plasmid DNA to skin fibroblasts.

Palmitic acid conjugates of poly-L-lysine (PLL-PA) were prepared, and their ability to deliver plasmid DNA into human skin fibroblasts was evaluated in vitro. The conjugates were capable of condensing a 4.7 kb plasmid DNA into 50-200 nm particles (mean +/- SD = 112 +/- 34 nm), which were slightly smaller than the particles formed by PLL (mean +/- SD = 126 +/- 51 nm).