Construction of multilayer films with bactericidal and long-term antitumor drug release properties as a non-vascular stent coating for therapy in obstruction

The construction of antibacterial and antitumor coatings could offer effective routes to improve the therapeutic effects of non-vascular stents for unresectable obstructions caused by malignant tumours. Herein, polyelectrolyte multilayers have been explored as bactericidal coatings with controlled antitumor drug release. To solve the challenges of loading and controlled release of small-molecule chemotherapeutic drugs in polyelectrolyte multilayers, the antitumor drug doxorubicin (DOX) was chemically conjugated onto polyethylenimine via cis aconitic anhydride (pH-sensitive linker), thus obtaining the polycation prodrug PEI-CA-DOX. Alginate sodium was oxidized (O-Alg) and mixed with DOX to prepare the O-Alg-DOX complex as a polyanion. QCM-D and contact angle tests were used to monitor and verify the progressive build-up of the PEI-CA-DOX/O-Alg-DOX multilayer films, which show a linear growth. The in vitro antibacterial tests indicated that the PEI-CA-DOX-terminated PEI-CA-DOX/O-Alg-DOX multilayers could kill the bacteria effectively. As-such multilayers also presented a long-term sustained DOX release behaviour in PBS due to the combination of slow release in PEI-CA-DOX and fast release in the O-Alg-DOX complex. The as-designed PEI-CA-DOX/O-Alg-DOX multilayers with combined antibacterial and antitumor properties may have great potential for applications in non-vascular stent coatings for palliative treatment of obstruction caused by malignant tumours.