Novel methodology based on biomimetic superhydrophobic substrates to immobilize cells in hydrogel spheres for tissue engineering applications

摘要

The low retention/integration of injected cells by host structures representsan important challenge in cell based therapies for regenerativemedicine purposes. Cell immobilization in hydrogels for target celldelivery has been developed to circumvent this issue. However, theexisting immobilization methodologies sometimes have several stepsunder wet conditions and present some drawbacks, including poorencapsulation efficiency and the use of harmful conditions for cells orother fragile molecules, such as proteins or growth factors. In order tosurpass these problems mesenchymal stem cells isolated from rats(rMSCs) bone marrow and fibronectin (FN) were immobilized in alginatebeads to mimic extracellular matrix environment using an innovativeapproach involving the jellification of the liquid precursor dropletsonto superhydrophobic surfaces. The alginate drops with cells and FNhardened very fast, at room temperature, into hydrogels spheres in anisolated environment which avoided the loss of FN and any contaminationor exchange of molecules with other liquid phase. The process forparticle fabrication employed allowed a very high efficiency on FNencapsulation and also the mild conditions prevented the loss of cellviability. Encapsulated rMSCs remained viable and were slowlyreleased from the beads during more than 20 days.