A stimuli-responsive, site-specific nano-drug delivery ideal for oral administration

by Ozkizilcik, Asya; Murphy, Suzanne; Tian, Z. Ryan

There is an increasing gap between the ever-growing demand for effective and patient-friendly drug delivery technologies and the longstanding drawbacks of conventional drug-delivery methods. Oral administration of drugs, the most economic and user-friendly method, for instance, has been suffered by (i) drugs' digestive decompn. in the low-pH environment in stomach and (ii) polymeric microcapsules with drug-inclusion voids disconnected by polymer-matrix. Therefore, increasing hope and in turn grand challenges have been put on the smart engineering of new nano- and micro-structured materials, devices and even systems. Here we report for the first time a hollow-microcapsule with (i) a tunable void-vol. for maximally loading drugs and (ii) a smart wall for time-programmable release of the drugs in response to the external stimuli such as pH-changes. In expt., the low-cost microcapsule was walled by self-assembled bionanofibers, and then surface-coated by a pH-sensitive biodegradable biopolymer with widely tunable layer-thicknesses and nanopore-closure down to sub-nm scale. In this preliminary work, methylene blue dye was loaded through diffusion as a model drug. For the first time, the in-vitro release profiles reached (i) a ~99% drug loading efficiency and (ii) sustained and programmable releases over a 48-h time period in simulated body fluid at 37 oC. This work proves a new scalable and highly translational technol. in biomedical engineering and nanomedicine.