Smooth muscle cell phenotype modulation and contraction on native and cross-linked polyelectrolyte multilayers.

Area of Science:

• Biomaterials Science
• Cell Biology
• Tissue Engineering

Background:

• Smooth muscle cells exist in two main phenotypes: a motile, synthetic state and a sessile, contractile state.
• Understanding how to control these cellular phenotypes is crucial for applications in regenerative medicine and disease treatment.

Purpose of the Study:

• To investigate the ability of biocompatible polyelectrolyte multilayers (PEMUs) with tunable stiffness to manipulate the phenotype of aortic smooth muscle cells.
• To correlate the mechanical properties of PEMUs with the resulting cellular phenotype and function.

Main Methods:

• Fabrication of polyelectrolyte multilayers (PEMUs) using poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA).
• Tuning PEMU stiffness via thermal cross-linking to form covalent amide bonds.
• Characterization of PEMU thickness and stiffness using Atomic Force Microscopy (AFM) and nanoindentation.
• Culturing rat aortic A7r5 smooth muscle cells on PEMUs with varying stiffness and assessing their phenotype markers and contractile function.

Main Results:

• Cross-linked PEMUs were thinner than native PEMUs, with Young's modulus ranging from 6 MPa to over 8 GPa.
• Cells cultured on native (non-cross-linked) PEMUs displayed synthetic phenotype markers (vimentin, tropomyosin 4, nmMHCIIB) and exhibited motility.
• Cells cultured on maximally cross-linked PEMUs expressed contractile phenotype markers (calponin, smMHC, myocardin, transgelin, smActin) and produced contractile force.

Conclusions:

• Tunable stiffness of polyelectrolyte multilayers (PEMUs) can effectively control smooth muscle cell phenotype.
• Stiffer PEMUs promote a contractile smooth muscle cell phenotype, while softer PEMUs support a synthetic phenotype.
• This approach offers a promising strategy for engineering tissues and controlling cell behavior in biomedical applications.