Departments of Chemistry and Chemical Engineering and the Texas Center for Superconductivity, University of Houston, Houston, Texas 77204, United States
Nanotechnology has greatly enhanced the field of medicine over the last decade. Within this field, advances in nanoparticle research have rendered them attractive candidates for drug delivery. Consequently, controlling the chemistry that occurs at the nanoparticle interface influences the efficiency of the drug-delivery system. In this review, we explore the role of coating materials, in the form of self-assembled monolayers (SAMs), in enhancing the interfacial properties of nanoparticles. We discuss how SAMs enhance the properties of particles, such as stability and dispersibility, as well as provide a platform for delivering biomolecules and other therapeutic agents. In addition, we describe recent methods for generating nanoparticles with targeted surface functionality using custom-designed SAMs. These functionalities offer marked advances to the three stages of a drug-delivery system: loading, delivery, and release of therapeutic molecules. A suitable functionalization strategy can provide a means for covalent or non-covalent immobilization of drug molecules. Moreover, a robust coating layer can aid the encapsulation of drug molecules and inhibit molecular degradation during the delivery process. A stimuli-responsive SAM layer can also provide an efficient release mechanism. Thus, we also review how stimuli-responsive coatings allow for the controlled release of therapeutic agents. In addition, we discuss the merits and limitations of stimuli-responsive SAMs as well as possible strategies for future delivery systems. Overall, advances in this research area allow for developing novel drug delivery methodologies with high efficiency and minimal toxicity.
