Large-Area Biomolecule Nanopatterns on Diblock Copolymer Surfaces for Cell Adhesion Studies

Abstract

Cell membrane receptors bind to extracellular ligands, triggering intracellular signal transduction pathways that result in specific cell function. Some receptors require to be associated forming clusters for effective signaling. Increasing evidences suggest that receptor clustering is subjected to spatially controlled ligand distribution at the nanoscale. Herein we present a method to produce in an easy, straightforward process, nanopatterns of biomolecular ligands to study ligand–receptor processes involving multivalent interactions. We based our platform in self-assembled diblock copolymers composed of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) that form PMMA nanodomains in a closed-packed hexagonal arrangement. Upon PMMA selective functionalization, biomolecular nanopatterns over large areas are produced. Nanopattern size and spacing can be controlled by the composition of the block-copolymer selected. Nanopatterns of cell adhesive peptides of different size and spacing were produced, and their impact in integrin receptor clustering and the formation of cell focal adhesions was studied. Cells on ligand nanopatterns showed an increased number of focal contacts, which were, in turn, more matured than those found in cells cultured on randomly presenting ligands. These findings suggest that our methodology is a suitable, versatile tool to study and control receptor clustering signaling and downstream cell behavior through a surface-based ligand patterning technique.

Sputter Deposition of Titanium on Poly(Methyl Methacrylate) Enhances Corneal Biocompatibility

“…16 To improve the interfacial adhesion, numerous surface modification approaches have been proposed, including biomineralization of hydroxyapatite (HAp) onto the PMMA surface, 17 calcium phosphate coating (d-CaP), 18 TiO 2 nanoparticle dip coating, 19 TiO 2 coating over a layer of polydopamine, 20 covalent functionalization with l-3,4-dihydroxyphenylalanine (l-DOPA), 21 and nanopatterning with cell adhesive peptides. 22 The superiority of Ti compared to PMMA as a substrate for cell growth has been previously demonstrated. 14,15,23,24 The application of a sandblasted Ti sleeve around the BK optic was previously shown to enhance the adhesion between the sleeve and a donor corneal graft 20 ; yet, it is expensive and requires precise machining of the Ti sleeve to perfectly fit the stem.…”

“… 16 To improve the interfacial adhesion, numerous surface modification approaches have been proposed, including biomineralization of hydroxyapatite (HAp) onto the PMMA surface, 17 calcium phosphate coating (d-CaP), 18 TiO 2 nanoparticle dip coating, 19 TiO 2 coating over a layer of polydopamine, 20 covalent functionalization with l -3,4-dihydroxyphenylalanine ( l -DOPA), 21 and nanopatterning with cell adhesive peptides. 22 …”

Electron Beam Lithography Fabrication of SU-8 Polymer Structures for Cell Studies

“…Fabrication approaches such as mask-based photolithography [22] and mask-less photolithography [23,24] are frequently applied, but structure resolution are for both techniques limited by the optical diffraction limit. Other approaches such as dip pen lithography [25], nano-sphere lithography [26], block-copolymer lithography [27] and other similar approaches [28] are able to perform structuring with sub-100 nm resolution, but have a limited throughput.…”

Covalent Functionalization of PMMA Surface with L‐3,4‐Dihydroxyphenylalanine (L‐DOPA) to Enhance its Biocompatibility and Adhesion to Corneal Tissue

“…This can impact homogeneity of the coating and lower the efficiency bond between PMMA and the recipient tissue, making these approach impractical for the clinical translation. 11 Recent studies to functionalize PMMA surfaces includes: large-area nanopatterning with cell adhesive peptides, 35 atmospheric pressure plasma plasma-assisted copolymerization of methyl methacrylate (MMA) with a vinyl derivative of L-DOPA, followed by deposit coating with reactive catechol/quinone groups suitable for protein covalent immobilization, 36 PMMA-MA nanoparticle surface modification with azide/carboxylate bifunctional group to enable assembly of small nanoparticle and their further coupling with oligonucleotides, 37 vaporphase nanopatterning of PMMA with aminosilanes via electron beam lithography, 38 surface functionalized of PMMA-based optical fiber probe with phenilboronic groups for glucose detection, 39 and hydrothermally treating the electrospun PMMA nanofibers with titanium nbutoxide precursor to form TiO 2 nanoparticles supported on PMMA nanofibers for photocatalytic degradation of methyl orange. 40 In this study, we covalently functionalized the PMMA surface with an L-3,4-dihydroxyphenylalanine amino acid (L-DOPA) and have studied cytotoxicity, biocompatibility, and the structural properties of coated PMMA, along with the interfacial adhesion strength of coated PMMA with human corneal tissues ( Figure 1b).…”