Native extracellular matrix (ECM) can exhibit cyclic nanoscale stretching and shrinking of ligands to regulate complex cell–material interactions. Designing materials that allow cyclic control of changes in intrinsic ligand‐presenting nanostructures in situ can emulate ECM dynamicity to regulate cellular adhesion. Unprecedented remote control of rapid, cyclic, and mechanical stretching (“ON”) and shrinking (“OFF”) of cell‐adhesive RGD ligand‐presenting magnetic nanocoils on a material surface in five repeated cycles are reported, thereby independently increasing and decreasing ligand pitch in nanocoils, respectively, without modulating ligand‐presenting surface area per nanocoil. It is demonstrated that cyclic switching “ON” (ligand nanostretching) facilitates time‐regulated integrin ligation, focal adhesion, spreading, YAP/TAZ mechanosensing, and differentiation of viable stem cells, both in vitro and in vivo. Fluorescence resonance energy transfer (FRET) imaging reveals magnetic switching “ON” (stretching) and “OFF” (shrinking) of the nanocoils inside animals. Versatile tuning of physical dimensions and elements of nanocoils by regulating electrodeposition conditions is also demonstrated. The study sheds novel insight into designing materials with connected ligand nanostructures that exhibit nanocoil‐specific nano‐spaced declustering, which is ineffective in nanowires, to facilitate cell adhesion. This unprecedented, independent, remote, and cytocompatible control of ligand nanopitch is promising for regulating the mechanosensing‐mediated differentiation of stem cells in vivo.
Native extracellular matrix (ECM) exhibits dynamic change in the ligand position. Herein, the ECM‐emulating control and real‐time monitoring of stem cell differentiation are demonstrated by ligand nanoassembly. The density of gold nanoassembly presenting cell‐adhesive Arg‐Gly‐Asp (RGD) ligand on Fe3O4(magnetite) nanoparticle in nanostructures flexibly grafted to material is changed while keeping macroscale ligand density invariant. The ligand nanoassembly on the Fe3O4can be magnetically attracted to mediate rising and falling ligand movements via linker stretching and compression, respectively. High ligand nanoassembly density stimulates integrin ligation to activate the mechanosensing‐assisted stem cell differentiation, which is monitored via in situ real‐time electrochemical sensing. Magnetic control of rising and falling ligand movements hinders and promotes the adhesion‐mediated mechanotransduction and differentiation of stem cells, respectively. These rising and falling ligand states yield the difference in the farthest distance (≈34.6 nm) of the RGD from material surface, thereby dynamically mimicking static long and short flexible linkers, which hinder and promote cell adhesion, respectively. Design of cytocompatible ligand nanoassemblies can be made with combinations of dimensions, shapes, and biomimetic ligands for remotely regulating stem cells for offering novel methodologies to advance regenerative therapies.
more » « less- PAR ID:
- 10449343
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Small
- Volume:
- 17
- Issue:
- 41
- ISSN:
- 1613-6810
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract -
more » « less
Abstract Various signals in tissue microenvironments are often unevenly distributed around cells. Cellular responses to asymmetric cell‐matrix adhesion in a 3D space remain generally unclear and are to be studied at the single‐cell resolution. Here, the authors developed a droplet‐based microfluidic approach to manufacture a pure population of single cells in a microscale layer of compartmentalized 3D hydrogel matrices with a tunable spatial presentation of ligands at the subcellular level. Cells elongate with an asymmetric presentation of the integrin adhesion ligand Arg‐Gly‐Asp (RGD), while cells expand isotropically with a symmetric presentation of RGD. Membrane tension is higher on the side of single cells interacting with RGD than on the side without RGD. Finite element analysis shows that a non‐uniform isotropic cell volume expansion model is sufficient to recapitulate the experimental results. At a longer timescale, asymmetric ligand presentation commits mesenchymal stem cells to the osteogenic lineage. Cdc42 is an essential mediator of cell polarization and lineage specification in response to asymmetric cell‐matrix adhesion. This study highlights the utility of precisely controlling 3D ligand presentation around single cells to direct cell polarity for regenerative engineering and medicine.
-
more » « less
The extracellular matrix (ECM) is a complex, hierarchical material containing structural and bioactive components. This complexity makes decoupling the effects of biomechanical properties and cell-matrix interactions difficult, especially when studying cellular processes in a 3D environment. Matrix mechanics and cell adhesion are both known regulators of specific cellular processes such as stem cell proliferation and differentiation. However, more information is required about how such variables impact various neural lineages that could, upon transplantation, therapeutically improve neural function after a central nervous system injury or disease. Rapidly Assembling Pentapeptides for Injectable Delivery (RAPID) hydrogels are one biomaterial approach to meet these goals, consisting of a family of peptide sequences that assemble into physical hydrogels in physiological media. In this study, we studied our previously reported supramolecularly-assembling RAPID hydrogels functionalized with the ECM-derived cell-adhesive peptide ligands RGD, IKVAV, and YIGSR. Using molecular dynamics simulations and experimental rheology, we demonstrated that these integrin-binding ligands at physiological concentrations (3–12 m
m ) did not impact the assembly of the KYFIL peptide system. In simulations, molecular measures of assembly such as hydrogen bonding and pi-pi interactions appeared unaffected by cell-adhesion sequence or concentration. Visualizations of clustering and analysis of solvent-accessible surface area indicated that the integrin-binding domains remained exposed. KYFIL or AYFIL hydrogels containing 3 mm of integrin-binding domains resulted in mechanical properties consistent with their non-functionalized equivalents. This strategy of doping RAPID gels with cell-adhesion sequences allows for the precise tuning of peptide ligand concentration, independent of the rheological properties. The controllability of the RAPID hydrogel system provides an opportunity to investigate the effect of integrin-binding interactions on encapsulated neural cells to discern how hydrogel microenvironment impacts growth, maturation, or differentiation. -
more » « less
Abstract The development of materials capable of varying macroscale ligand distributions can emulate an extracellular matrix (ECM) remodeling and regulate the adhesion and polarization of macrophages. In this report, negatively charged slidable nano‐ligands are assembled and then conjugated to a positively charged substrate via electrostatic interaction. The negatively charged slidable nano‐ligands are prepared by coating magnetic nanoparticles with a polymer linker and negatively charged RGD ligand. The nano‐ligand sliding is characterized under an external magnetic field, which spatiotemporally alters macroscale ligand density. To the best of knowledge, this is the first demonstration that magnetic maipulation of the macroscale ligand density inhibits inflammatory M1 phenotype but stimulates the adhesion and regenerative M2 phenotype of host macrophages. Furthermore, it is elucidated that the magnetic attraction of the slidable nano‐ligand facilitates the assembly of adhesion structures in macrophages, thereby stimulating their regenerative M2 phenotype. The design of ECM‐emulating materials that allow remote, spatiotemporal, and reversible controllability of macroscale ligand density provides an appealing strategy in the spatiotemporal regulation of immunomodulatory tissue‐regenerative responses to implants in vivo.
-
Jian Yang (Ed.)Dynamic regulation of cell-extracellular matrix (ECM)-material interactions is crucial for various biomedical applications. In this study, a light-activated molecular switch for the modulation of cell attachment/detachment behaviors was established on monolayer graphene (Gr)/n-type Silicon substrates (Gr/Si). Initiated by light illumination at the Gr/Si interface, pre-adsorbed proteins (bovine serum albumin, ECM proteins collagen-1, and fibronectin) underwent protonation to achieve negative charge transfer to Gr films (n-doping) through π-π interactions. This n-doping process stimulated the conformational switches of ECM proteins. The structural alterations in these ECM interactors significantly reduced the specificity of the cell surface receptor-ligand interaction (e.g., integrin recognition), leading to dynamic regulation of cell adhesion and eventual cell detachment. RNA-sequencing results revealed that the detached bone marrow mesenchymal stromal cell sheets from the Gr/Si system manifested regulated immunoregulatory properties and enhanced osteogenic differentiation, implying their potential application in bone tissue regeneration. This work not only provides a fast and feasible method for controllable cells/cell sheets harvesting but also gives new insights into the understanding of cell-ECM-material communications.more » « less
