Metal–organic frameworks (MOFs) are porous materials
with
adsorption, storage, and separation capabilities due to their high
specific surface areas and large pore volumes. MOFs are thus used
in biomedical applications, and MOF nanoparticles have been widely
studied as nanocarriers for drug delivery systems. Several research
groups recently reported that specific MOF nanoparticles can adsorb
and retain proteins, suggesting to us that MOF nanoparticles may have
advantages as novel cell culture scaffolds. However, MOF nanoparticles
cannot be used as two-dimensional scaffolds for cells. We therefore
established a bottom-up technique to construct two-dimensional MOFs
[MIL-53 (Al)] on polymer films. The developed two-dimensional MIL-53
(Al) film [fMIL-53 (Al)] exhibited high serum protein adsorption,
retention, and replenishment capabilities as compared to conventional
cell culture scaffolds. β-Galactosidase, used as a model protein,
adsorbed on fMIL-53 (Al) exhibited original enzymatic activity, indicating
that proteins are not denatured during the adsorption process. The
viability of mouse myoblast cells (C2C12) cultured on fMIL-53 (Al)
was 100%, indicating the cell compatibility of fMIL-53 (Al). Importantly,
C2C12 cells cultured on serum protein-preadsorbed fMIL-53 (Al) exhibited
excellent long-term adhesion, morphology, and proliferation even in
a medium lacking serum proteins, demonstrating an important advantage
of fMIL-53 (Al) as a cell culture scaffold, given that conventional
cell culture scaffolds typically require a serum-containing medium
to support stable cell adhesion and proliferation. To our knowledge,
this is the first report regarding the application of MOFs as cell
culture scaffolds and will serve as a starting point for studying
two- and three-dimensional MOF-based cellular scaffolds for cell culture
systems and for in vitro and in vivo tissue engineering.