Sporopollenin exine capsules with polypeptide multilayer films promoting cell adhesion

Abstract

Sporopollenin exine capsules (SECs), extracted from plant pollen, are emerging as attractive and natural microcapsules for a wide range of bio-composite applications due to their abundant availability, chemical and mechanical robustness, species-specific architectural features, striking structural uniformity, and large inner cavity. However, SECs have a predominantly hydrophobic interface hindering their application in biomaterials. Thus, developing robust surface functionalization strategies to increase their hydrophilicity would open the door to interfacing microcapsules with cells. Herein, we create SECs with increased surface hydrophilicity coated by polypeptide multilayer films using layer-by-layer (LbL) self-assembly technology. Furthermore, human bone marrow-derived stem cells adhere more to these LbL-treated SECs acting as seed cells for tissue engineering. In summary, our findings demonstrate that LbL modification of SECs improves their functional properties and has broad implications across bio-composite applications.