The development of 2D or 3D bioactive platforms for rapidly
isolating
pure populations of cells from adult stem cells holds promise for
advancing the understanding of cellular mechanisms, drug testing,
and tissue engineering. Over the years, methods have emerged to synthesize
bioactive micro- and nanostructured 2D materials capable of directing
stem cell fate. We introduce a novel method for randomly micro- or
nanopatterning any protein/peptide onto both 2D and 3D scaffolds via
spray technology. Our goal is to investigate the impact of arranging
bioactive micropatterns (ordered vs disordered) on surfaces to guide
human mesenchymal stem cell (hMSC) differentiation. The spray technology
efficiently coats materials with controlled, cost-effective bioactive
micropatterns in various sizes and shapes. BMP-2 mimetic peptides
were covalently grafted, individually or in combination with RGD peptides,
onto activated polyethylene terephthalate (PET) surfaces through a
spraying process, incorporating nano/microscale parameters like size,
shape, and composition. The study explores different peptide distributions
on surfaces and various peptide combinations. Four surfaces were homogeneously
functionalized with these peptides (M1 to M4 with various densities
of peptides), and six surfaces with disordered micro- and nanopatterns
of peptides (S0 to S5 with different sizes of peptide patterns) were
synthesized. Fluorescence microscopy assessed peptide distribution,
followed by hMSC culture for 2 weeks, and evaluated osteogenic differentiation
via immunocytochemistry and RT-qPCR for osteoblast and osteocyte markers.
Cells on uniformly peptide-functionalized surfaces exhibited cuboidal
forms, while those on surfaces with disordered patterns tended toward
columnar or cuboidal shapes. Surfaces S4 and S5 showed dendrite-like
formations resembling an osteocyte morphology. S5 showed significant
overexpression of osteoblast (OPN) and osteocyte markers (E11, DMP1,
and SOST) compared to control surfaces and other micropatterned surfaces.
Notably, despite sharing an equivalent quantity of peptides with a
homogeneous functionalized surface, S5 displayed a distinct distribution
of peptides, resulting in enhanced osteogenic differentiation of hMSCs.