Hydrogels with cell adhesive properties are a promising approach to promote bone tissue regeneration. Among the different polymers available to design hydrogels, alginate has been widely used, due to its high versatility and availability, biocompatibility, application to different fabrication processes and the ease in tuning its intrinsic properties [1]. However, alginate is a bioinert material and thus, it does not naturally possess adhesive cues to promote cell attachment [2]. In addition, bacterial colonization of biomaterials is also a problematic concern in the clinics. Indeed, bacterial infections and the possibility of biofilm formation are one of the major causes of implant failure, representing about 20% of failures [3]. Thus, addressing bioactivity of hydrogels as well as inhibiting bacterial colonization are crucial aspects to ensure the success of an implant.

To manage both issues, an alginate hydrogel modified with a multifunctional peptide containing the well-known RGD cell adhesive motif in combination with an antibacterial peptide derived from the 1-11 region of lactoferrin (LF) was developed [4]. The RGD-LF branched peptide was successfully linked to the alginate by carbodiimide chemistry, as demonstrated by 1 H NMR and fluorescence experiments. The functionalized alginate hydrogel presented good physicochemical properties (porosity, swelling and rheological behavior). Moreover, biological characterization demonstrated the ability of the modified hydrogels to promote ALP activity of human bone marrow derived mesenchymal stem cells (hBMMSCs) as well as to decrease bacterial viability and the possible early colonization of the hydrogel in both Gram-positive and Gram-negative models.

In summary, the functionalized hydrogels presented in this work, with the dual capacity to promote cell adhesion while preventing bacterial contamination, would have potential application in bone tissue engineering applications.

References

[1] A.C. Hernández-González, Carbohydr Polym, 2020, 229, 115514.

[2] F. Melo-Fonseca, Stem Cell Rev Reports. 2020, 16(6), 1121-1138.

[3] R.E. Delanois, J Arthroplasty, 2017; 32(9), 2663-2668.

[4] M. Hoyos-Nogués; ACS Appl Mater Interfaces, 2017, 9(26), 21618-21630.