Introduction: Surface modification has become a major challenge over the past two decades in order to improve the interface between a biomaterial and a host. Elastin-like recombinamers (ELRs) are a fine example of biocompatible stimuli-responsive material and self-assembly towards temperature and their recombinant nature makes them attractive for tissue engineering applications. Their smart nature can be exploited for drug delivery systems and controlled protein or cell adhesion. Two osteogenic ELRs were used with chitosan using a multilayer approach: one was labeled HAP3, and the second H3A20H3, composed of 3 blocks – 1 nonpolar and 2 polar containing the osteoconductive sequence. We hypothesized that different ELR’s, although similar in sequence, behave differently when used along with polysaccharides.

Materials and Methods: A quartz-crystal microbalance with dissipation monitoring (QCM-D) was used for monitoring in situ deposition of chitosan and HAP3 or H3A20H3 in parallel onto gold-coated sensors. Contact angles were measured in a DataPhysics OCA20 system. The coatings were prepared on glass slides. Temperature-dependent contact angles were measured. The samples were immersed in a beaker of PBS at room temperature or at 50 ºC. After 1 hour, the samples were withdrawn and contact angles were measured.

Results: The number of layers was chosen after QCM-D analysis: while it was possible to buildup HAP3-based multilayers, using H3A20H3 only allowed to conceive 1 bilayer, what is attributed to the exposure of the nonpolar blocks to the surface, decreasing the affinity to charged species and aqueous solutions. This is in accordance with the surface wettability behavior shown by the contact angle measurements.

Discussion and Conclusions: The results show that ELRs are suitable materials to conceive coatings along with polysaccharides. Their recombinant nature may allow the production of materials not only more suitable for a multilayer approach but also for specific applications by adding bioactive sequences and organizing their structure in blocks.