Facile fabrication of polyurethane microcapsules carriers for tracing cellular internalization and intracellular pH-triggered drug release

A tailor-made traceable pH-sensitive drug delivery system based on polyurethane (PU) microcapsules was fabricated using a facile double-emulsion method containing 3,3'-dioctadecyloxacarbocyanine per chlorate, doxorubicin (DOX) and sodium bicarbonate (NaHCO3). When PU microcapsules were immersed in acidic media, NaHCO3 could react with the H+ to quickly produce CO2 bubbles to puncture the PU shell, resulting in rapid release of DOX to promptly reach the intracellular drug therapeutic threshold to kill cancer cells in a short period. Confocal laser scanning microscopic analysis showed that these traceable pH-sensitive drug carriers can be easily internalized by BGC 823 and Hela cells, and the loaded DOX can quickly release from PU microcapsules in the endo-/lysosomes to be mainly resided in cell nuclei. This traceable pH-sensitive drug carrier can achieve on-demand controlled release profiles for visualization of cancer therapy. Thus, it is a potential candidate for anticancer drug delivery system in advanced cancer therapy. (C) 2017 Elsevier B.V. All rights reserved.