ABSTRACT
The paper reports on covalent linking of different alkyne-containing (decyne, ethynylferrocene, and N-propargyl-1-pyrenecarboxamide) compounds to azide-terminated nanodiamond (ND) particles. Azide-terminated particles (ND-N(3)) were obtained from amine-terminated nanodiamond particles (ND-NH(2)) through the reaction with 4-azidobenzoic acid in the presence of a carbodiimide coupling agent. Functionalized ND particles with long alkyl chain groups can be easily dispersed in various organic solvents without any apparent precipitation after several hours. The course of the reaction was followed using Fourier transform infrared (FT-IR) spectroscopy, UV/vis spectroscopy, fluorescence, cyclic voltammetry, thermogravimetric analysis (TGA), and particle size measurements. The surface loading of pyrene bearing a terminal acetylene group was found to be 0.54 mmol/g. Because of its gentle nature and specificity, the chemistry developed in this work can be used as a general platform for the preparation of functional nanoparticles for various applications.
Subject(s)
Diamond/chemistry , Nanoparticles/chemistry , Nanotechnology/methods , Molecular Structure , Spectrophotometry, Ultraviolet/methods , Spectroscopy, Fourier Transform InfraredABSTRACT
Many neurodegenerative diseases, cancer, and infections of the brain become more prevalent as populations become older. Despite major advances in neuroscience, the blood-brain barrier (BBB) ensures that many potential therapeutics cannot reach the central nervous system (CNS). The BBB is formed by the complex tight junctions between the endothelial cells of the brain capillaries and their low endocytic activity. It results in the capillary wall that behaves as a continuous lipid bilayer and prevents the passage of polar substances. Drug delivery to the brain has remained one of the most vexing problems in translational neuroscience research, because of the difficulties posed by the BBB. Several strategies for delivering drugs to the CNS have been developed. This review rationalizes the strategies to target drugs to the brain by using different colloids.
Subject(s)
Blood-Brain Barrier/drug effects , Brain/drug effects , Colloids/pharmacokinetics , Drug Delivery Systems/methods , Nanoparticles/therapeutic use , Animals , Blood-Brain Barrier/metabolism , Brain/blood supply , Brain/metabolism , Capillaries/drug effects , Capillaries/metabolism , Colloids/therapeutic use , Drug Delivery Systems/trends , Endothelial Cells/drug effects , Endothelial Cells/metabolism , Humans , Lipids/chemistry , Lipids/pharmacokinetics , Membrane Lipids/metabolism , Polymers/pharmacokineticsABSTRACT
In order to graft an amphiphilic polysaccharide to lipid nanocapsules, we present here a new method of dextran lipidation. The lipidation strategy is based on the formation of an oxime linkage between the amphiphilic hydroxylamine C16E20ONH2 and the reductive end of a 40 kDa dextran. This chemoselective reaction allows us to control the lipidation site and the number of lipid introduced on the dextran molecule. This new amphiphilic dextran was used to coat the surface of lipid nanocapsules. The coating efficiency was followed by dynamic light scattering and the presence of the polysaccharide was confirmed by (1)H NMR and observed by electronic microscopy.
