Patterning Nanoparticles in a Three-Dimensional Matrix Using an Electric-Field-Assisted Gel Transferring Technique (original) (raw)
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Patterning Proteins and Cells Using Two-Dimensional Arrays of Colloids
Langmuir, 2003
A simple method is described for controlling the organization of proteins on surfaces using two-dimensional arrays of micron-sized colloidal particles. Suspensions of colloids functionalized with proteins are deposited onto coverslips coated with gold using a combination of gravitational settling and applied electrical fields. Varying settling time and particle concentration controls the density of particles on the substrate. Surface coverage ranged from an essentially continuous coating of protein on close-packed arrays to domains of protein separated by distances as large as 16 µm. Colloidal particle arrays were also patterned into 500 µm islands on substrates using elastomeric lift-off membranes. The applicability of this approach to the promotion of fibroblast cell adhesion and spreading was demonstrated using particles coated with the cell adhesion protein fibronectin. Behavior of adherent cells varied with particle density. This method provides a general strategy for controlling the organization of functional proteins at surfaces on three length scales: the size of individual colloidal particles, the spacing between particles, and the organization of particles in patterned arrays.
A photolabile hydrogel for guided three-dimensional cell growth and migration
Nature Materials, 2004
issue engineering aims to replace, repair or regenerate tissue/organ function, by delivering signalling molecules and cells on a three-dimensional (3D) biomaterials scaffold that supports cell infiltration and tissue organization 1,2. To control cell behaviour and ultimately induce structural and functional tissue formation on surfaces, planar substrates have been patterned with adhesion signals that mimic the spatial cues to guide cell attachment and function 3-5. The objective of this study is to create biochemical channels in 3D hydrogel matrices for guided axonal growth.An agarose hydrogel modified with a cysteine compound containing a sulphydryl protecting group provides a photolabile substrate that can be patterned with biochemical cues. In this transparent hydrogel we immobilized the adhesive fibronectin peptide fragment, glycinearginine-glycine-aspartic acid-serine(GRGDS),in selected volumes of the matrix using a focused laser.We verified in vitrothe guidance effects of GRGDS oligopeptide-modified channels on the 3D cell migration and neurite outgrowth.This method for immobilizing biomolecules in 3D matrices can generally be applied to any optically clear hydrogel, offering a solution to construct scaffolds with programmed spatial features for tissue engineering applications. Hydrogels have been widely studied as tissue scaffolds because they are biocompatible and non-adhesive to cells, allowing cell adhesion to be programmed in 6-8. Current microfabrication methods for 3D hydrogel matrices with controlled intrinsic structure mainly include photolithographic patterning 9-11 , microfluidic patterning 12 , electrochemical deposition 13 and 3D printing 14 .Notably,although these layering techniques can conveniently shape the hydrogel on X-Y planes, they have limited control over both the coherence of the layers along the z direction and the local chemistry. Combining photolabile hydrogel matrices with focused light provides the possibility of eliminating the layering process and directly modifying the local physical or chemical properties in 3D. This results in a promising (and perhaps facile) way to fabricate novel tissue constructs 15,16 ,as is described herein to control cell behaviour by controlling the local chemical properties of gels. Reconstituting adhesive biomolecules into biomaterials is of great importance to understanding cell-substrate interactions that can be translated to tissue-regeneration designs. Using 2D lithographic techniques,adhesive biomolecules can be localized in arbitrary shapes and sizes 17,18 .For example,patterning narrow strips of the extracellular
3D electrophoresis-assisted lithography (3DEAL) for patterning hydrogel environments
The ability to easily generate anisotropic hydrogel environments made from functional molecules with microscale resolution is an exciting possibility for the biomaterials community. This study reports a novel 3D-Electrophoresis-Assisted-Lithogrpahy (3DEAL) platform that combines elements from proteomics, biotechnology, and microfabrication to print well-defined 3D molecular patterns within hydrogels. The potential of the 3DEAL platform is assessed by patterning immunoglobulin G, fibronectin, and elastin within nine widely used hydrogels and characterizing pattern depth, resolution, and aspect ratio. Furthermore, the technique's versatility is demonstrated by fabricating complex patterns including parallel and perpendicular columns, curved lines, gradients of molecular composition, and patterns of multiple proteins ranging from tens of microns to centimeters in size and depth. The functionality of the printed molecules is assessed by culturing NIH-3T3 cells on a fibronectin-patterned polyacrylamide-collagen hydrogel and selectively supporting cell growth. 3DEAL is a simple, accessible, and versatile hydrogel-patterning platform based on controlled molecular printing that may enable the development of tunable, chemically anisotropic, and hierarchical 3D environments.
Functionalized Hydrogel Surfaces for the Patterning of Multiple Biomolecules
Journal of Biomedical Materials Research Part A, 2007
Patterning of multiple proteins and enzymes onto biocompatible surfaces can provide multiple signals to control cell attachment and growth. Acrylamide-based hydrogels were photo-polymerized in the presence of streptavidin-acrylamide, resulting in planar gel surfaces functionalized with the streptavidin protein. This surface was capable of binding biotin-labeled biomolecules. The proteins fibronectin and laminin, the enzyme alkaline phosphatase, and the photo-protein R-phycoerythrin were patterned using soft lithographic techniques. Polydimethylsiloxane stamps were used to transfer biotinylated proteins onto streptavidin-conjugated hydrogel surfaces. Stamped biomolecules were spatially resolved to feature sizes of 10 mum. Fluorescence measurements were used to assess protein transfer and enzyme functionality on modified surfaces. Our results demonstrate that hydrogel surfaces can be patterned with multiple proteins and enzymes, with retention of biological and catalytic activity. These surfaces are biocompatible and provide cues for cell attachment and growth.
Cell Patterning on Biological Gels via Cell Spraying through a Mask
Tissue Engineering, 2005
We present an easily applicable and inexpensive method for patterning cells on arbitrary surfaces including biological gels with little loss of viability or function. Single-cell suspensions of human umbilical vein endothelial cells and NIH 3T3 fibroblasts were sprayed with an off-the-shelf airbrush through a mask to create 100-m scale patterns on collagen gels. Three-dimensional patterns were created by layering a collagen gel on top of the first pattern and patterning the top gel. Coculture of rat hepatocytes with NIH 3T3 patterns on collagen gels resulted in localized increased activity of cytochrome P-450 along the pattern. These results suggest that cell spraying is a useful tool for the study of heterotypic cellular interactions and tissue-engineering applications on biologically relevant matrices, and for the creation of three-dimensional cell patterns in vitro.
2019
We demonstrate the use of electric fields to rapidly form gels of the biopolymer alginate (Alg) in specific three-dimensional (3-D) shapes and patterns. In our approach, we start with a gel of the biopolymer agarose, which is thermoresponsive and hence can be molded into a specific shape. The agarose mold is then loaded with Ca2+ cations and placed in a beaker containing an Alg solution. The inner surface of the beaker is surrounded by aluminum foil (cathode), and a copper wire (anode) is stuck in the agarose mold. These are connected to a direct current (DC) power source, and when a potential of ∼10 V is applied, an Alg gel is formed in a shape that replicates the mold. Gelation occurs because the Ca2+ ions electrophoretically migrate away from the mold, whereupon they cross-link the Alg chains adjacent to the mold. At low Ca2+ (0.01 wt %), the Alg gel layer grows outward from the mold surface at a steady rate of about 0.8 mm/min, and the gel stops growing when the field is switche...
Advanced Functional Materials
The ability to easily generate anisotropic hydrogel environments made from functional molecules with microscale resolution is an exciting possibility for the biomaterials community. This study reports a novel 3D-Electrophoresis-Assisted-Lithogrpahy (3DEAL) platform that combines elements from proteomics, biotechnology, and microfabrication to print well-defined 3D molecular patterns within hydrogels. The potential of the 3DEAL platform is assessed by patterning immunoglobulin G, fibronectin, and elastin within nine widely used hydrogels and characterizing pattern depth, resolution, and aspect ratio. Furthermore, the technique's versatility is demonstrated by fabricating complex patterns including parallel and perpendicular columns, curved lines, gradients of molecular composition, and patterns of multiple proteins ranging from tens of microns to centimeters in size and depth. The functionality of the printed molecules is assessed by culturing NIH-3T3 cells on a fibronectin-patterned polyacrylamide-collagen hydrogel and selectively supporting cell growth. 3DEAL is a simple, accessible, and versatile hydrogel-patterning platform based on controlled molecular printing that may enable the development of tunable, chemically anisotropic, and hierarchical 3D environments.
Synthesis and patterning of hydrogel-nanoparticle composites
Nanoengineering: Fabrication, Properties, Optics, and Devices V, 2008
We have developed a novel method for patterning nanoscale composite hydrogel materials on silicon through electron beam lithography. Gold particles were introduced into poly N-isopropylacrylamide (PNIPAam) patterned by e-beam lithography. By including BAC, the polymer can covalently bond to the colloidal gold nanoparticles. Such composites can be stable for long periods of time. We describe the structure, quality, and properties of the resulting patterned hydrogel-nanoparticle composite films.
Fabrication of micropatterns of nanoarrays on a polymeric gel surface
Nanoscale, 2010
Micro-nano patterns of gold on the surface of poly(ethylene glycol) (PEG) hydrogels were prepared. The approach combines the technique of conventional photolithography (a top-down method for micropatterns), block copolymer micelle nanolithography (a bottom-up method for gold nanopatterns), and a linker-assistant technique to transfer a pattern on a hard surface to a polymeric surface. Hybrid micro-nano patterns on hydrogels were characterized using scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The patterned Au nanoparticles were further modified by a peptide containing arginine-glycine-aspatate (RGD). The celladhesion contrast of the patterned hydrogel surface was confirmed by preliminary cell experiments.