Among the innovative therapeutic techniques in orthopedics, a considerable interest arose around Mesenchymal Stem Cells (MSCs) - based therapies for one-step clinical applications. In order to achieve a better cell targeting at the injury site, these applications would need a specific cell delivery system. Hence, in this study a protocol for an efficient cell delivery based on the rapid cell adhesion on the surface of lyophilized fibroin-coated alginate microcarriers (L-FAMs) was optimized by the Design of Experiment (DoE) method in accordance with the minimum requirements for one-step clinical application. Specific parameters (seeding time, intermittent or not dynamic culture, stirring speed and volume of cell suspension) were combined in 13 different protocols, tested on human Adipose derived stem cells - ASCs (n=3). Cell adhesion rate in term of DNA quantification and metabolic activity of cells adhered on L-FAMs, and their qualitative observations by Calcein Staining were evaluated. The data showed that a suspension of 3.75 × 105 cells/ml and 10 mg/ml of FAMs, 12.3 rpm of stirring speed and 85.6 minutes of seeding time are the most performing combination of parameters. The final protocol was then tested and validated on both hASCs (n=3) and human bone marrow derived stem cells - BMSCs (n=3). The results confirmed a high adhesion rate of cells, homogenously arranged on the surface of L-FAMs without cell cluster formation. Even though further optimizations are still needed, the present protocol may represent the proof of concept for the introduction of L-FAMs as carriers in one-step intraoperative applications.
