Encapsulation and Release Mechanisms in Coordination Polymer Nanoparticles

Abstract

The interplay of guest encapsulation and release mechanisms in nanoscale metal–organic vehicles and its effect on the drug‐delivery kinetics of these materials were investigated through a new multidisciplinary approach. Two rationally‐designed molecular guests were synthesized, which consist of a red‐fluorescent benzophenoxazine dye covalently tethered to a coordinating catechol group and a protected, non‐coordinating catechol moiety. This allowed loading of the guests into compositionally and structurally equivalent coordination polymer particles through distinct encapsulation mechanisms: coordination and mechanical entrapment. The two types of particles delivered their fluorescent cargo with remarkably different kinetic profiles, which could be satisfactorily modeled considering degradation‐ and diffusion‐controlled release processes. This demonstrates that careful selection of the method of guest incorporation into coordination polymer nanoparticles allows selective tuning of the rate of drug delivery from these materials and, therefore, of the time window of action of the encapsulated therapeutic agents.

Nanomedicine Applications of Hybrid Nanomaterials Built from Metal–Ligand Coordination Bonds: Nanoscale Metal–Organic Frameworks and Nanoscale Coordination Polymers

“…The released drug will undergo aquation and binds to DNA to induce apoptosis. 242 Drugs loaded into the NCPs via encapsulation will be released through free diffusion, while drugs covalently conjugated to the frameworks can only be released after the nanoparticles are degraded. The stability of NMOFs in the physiological environment should be addressed before their successful applications in drug delivery, imaging, and sensing.…”

Versatile iron–catechol-based nanoscale coordination polymers with antiretroviral ligand functionalization and their use as efficient carriers in HIV/AIDS therapy

“…29,[36][37][38] Less explored has been the chemical entrapment through tethering of active drugs as chelating ligands, in spite of the fact that its efficiency has already been reported. 39 Moreover, the chemical flexibility of organic synthesis may allow for the design of drugs (ligands) cleaved under physiological conditions.…”

Amorphous Coordination Polymer Particles for Biomedicine

“…In a very recent study, a detailed rationalization of guest encapsulation and release mechanisms was performed with the aim of understanding the drug delivery kinetics of most emerging CPPs and, consequently, to fully assess their potential use as nanocarriers for therapeutic purposes [50]. Thus, two morphologically equivalent CPPs based on cobalt with general composition [Co(bix)(3,5-dbsq)(3,5-dbcat)] were used as carriers, where bix is a flexible bis-imidazole bridging ligand and 3,5-dbsq and 3,5-dbcat stand for the semiquinonate radical and catecholate forms of 3,5-di-tert-butylcatechol.…”