In this study, a new formulation of nanoparticles (NPs) based on the electrostatic interaction between
chitosan and chondroitin sulphate (CH–CS NPs) is proposed for the controlled release of proteins and
growth factors (GFs), specifically platelet lysates (PLs). These nanoparticulate carriers are particularly
promising for protein entrapment because the interactions between the polysaccharides and
the entrapped proteins mimic the interactions between chondroitin sulphate and proteins in the
native extracellular matrix (ECM). Spherical non-cytotoxic NPs were successfully produced, exhibiting
high encapsulation efficiency for physiological levels of GFs and a controlled protein release
profile for >1 month. Moreover, it was also observed that these NPs can be uptaken by human
adipose-derived stem cells (hASCs), depending on the concentration of NPs in the culture medium
and incubation time. This shows the versatility of the developed NPs, which, besides acting as a protein
delivery system, can also be used in the future as intracellular carriers for bioactive agents, such
as nucleotides. When the PL-loaded NPs were used as a replacement of bovine serum for in vitro
hASCs culture, the viability and proliferation of hASCs was not compromised. The release of PLs from
CH–CS NPs also proved to be effective for the enhancement of in vitro osteogenic differentiation of
hASCs, as shown by the increased levels of mineralization, suggesting not only the effective role of
the delivery system but also the role of PLs as an osteogenic supplement for bone tissue engineering
and regenerative medicine applications.