Abstract: Nitrogen-containing lipids prepared from the conjugate addition of amines to acrylates, acrylamides, or other carbon-carbon double bonds conjugated to electron-withdrawing groups are described. Methods of preparing these lipids from commercially available starting materials are also provided. These amine-containing lipids or salts forms of these lipids are preferably biodegradable and biocompatible and may be used in a variety of drug delivery systems. Given the amino moiety of these lipids, they are particularly suited for the delivery of polynucleotides. Complexes or nanoparticles containing the inventive lipid and polynucleotide have been prepared. The inventive lipids may also be used to in preparing microparticle for drug delivery. They are particularly useful in delivering labile agents given their ability to buffer the pH of their surroundings.

Abstract: A system for electrostatically coating particles is provided. The system is particularly well suited for coating charged drug delivery particles (e.g., nanoparticles, microparticles) with a coating of opposite charge. The coating may include a targeting moiety such as a small molecule ligand, peptide, protein, aptamer, etc. The coated particles are biodegradable and/or biocompatible, have a near neutral zeta (?) potential, and are stable in serum. The invention also provides pharmaceutical compositions and kits including the inventive coated particles. Methods of preparing and using the inventive particles are also included.