Self-Assembling Nanoparticles of Amphiphilic Polymers for In Vitro and In Vivo FRET Imaging

Abstract

Self-assembling nanoparticles of amphiphilic polymers are viable delivery vehicles for transporting hydrophobic molecules across hydrophilic media. Noncovalent contacts between the hydrophobic domains of their macromolecular components are responsible for their formation and for providing a nonpolar environment for the encapsulated guests. However, such interactions are reversible and, as a result, these supramolecular hosts can dissociate into their constituents amphiphiles to release the encapsulated cargo. Operating principles to probe the integrity of the nanocarriers and the dynamic exchange of their components are, therefore, essential to monitor the fate of these supramolecular assemblies in biological media. The co-encapsulation of complementary chromophores within their nonpolar interior offers the opportunity to assess their stability on the basis of energy transfer and fluorescence measurements. Indeed, the exchange of excitation energy between the entrapped chromophores can only occur if the nanoparticles retain their integrity to maintain donors and acceptors in close proximity. In fact, energy-transfer schemes are becoming invaluable protocols to elucidate the transport properties of these fascinating supramolecular constructs in a diversity of biological preparations and can facilitate the identification of strategies to deliver contrast agents and/or drugs to target locations in living organisms for potential diagnostic and/or therapeutic applications.

Hydrazone-Based Amphiphilic Brush Polymer for Fast Endocytosis and ROS-Active Drug Release

“…A ROS-responsive drug delivery system has the potential to regulate the efficacy of anti-ROS drugs by acting as a protective shield for drugs prior to reaching their intended site, and then promptly releasing the encapsulated drug when exposed to a ROS-rich environment. Amphiphilic polymers have emerged as a promising class of drug carriers, as they can encapsulate hydrophobic drugs and form nanosized micelles in aqueous conditions, offering an effective method for sequestering hydrophobic drug molecules . ROS-responsive amphiphilic polymers have been explored for drug delivery, including those containing thioether, selenium/tellurium, thioketal, polysaccharide, aminoacrylate, boronic ester, peroxalate ester, and polyproline. − The drug release mechanisms include solubility change-induced carrier disassembly and cleavage-induced carrier degradation .…”