Patterning Nanoparticles in a Three-Dimensional Matrix Using an Electric-Field-Assisted Gel Transferring Technique

Abstract

In this paper, we describe an electric-field-assisted gel transferring technique for patterning on two- and three-dimensional media. The transfer process starts with the preparation of a block of agarose gel doped with charged nanoparticles or molecules on top of a screen mask with desired patterns. This gel/mask construct is then brought into contact with the appropriate receiving medium, such as a polymer membrane or a piece of flat hydrogel. An electric field is applied to transfer the doped charged nanoparticles or molecules into the receiving medium with a pattern defined by the screen mask. This printing method is rapid and convenient, the results are reproducible, and the process can be done without using expensive micro/nanofabrication facilities. The capability to pattern structures such as arrays of nanoparticles into three-dimensional hydrogels may find applications for positioning cell signaling molecules to control cell growth and migration.

Composition‐dependent underwater adhesion of catechol‐bearing hydrogels

“…Hydrogel‐based bioelectronics fabricated on ultracompliant substrates could improve device integration by reducing the modulus mismatch at the abiotic–biotic interface . However, integrating electronic materials with hydrogels is challenging because hydrated networks exhibit large dimensional strains and prohibit vacuum‐based materials processing . Electronic materials have been integrated with hydrogels through in situ micropatterned electropolymerization …”

“…9 However, integrating electronic materials with hydrogels is challenging because hydrated networks exhibit large dimensional strains and prohibit vacuum-based materials processing. 10 Electronic materials have been integrated with hydrogels through in situ micropatterned electropolymerization. 11,12 Transfer printing of electronic materials to adhesive hydrogels is a viable processing strategy because it decouples microelectronic fabrication processes from substrate composition.…”

3D Electrophoresis‐Assisted Lithography (3DEAL): 3D Molecular Printing to Create Functional Patterns and Anisotropic Hydrogels

“…These results demonstrate the capacity of the 3DEAL platform to move and localize molecules within multiple types of hydrogels to create deep patterns with micro‐scale resolution and aspect ratios of up to 1:100 (diameter:depth), contributing to current efforts aiming to develop ever more complex scaffolds . For example, creative methods developed by Ahadian et al based on dielectrophoresis and Dai using electrophoresis have enabled patterning of aligned carbon nanotubes down to 50 µm in depth and nanoparticles down to 20 µm in depth, respectively. However, these techniques have been limited to using nonbiological molecules and creating relatively shallow patterns within gels.…”

“…Recently, there has been interest in the use of electric fields (EFs) for 3D patterning. This method controls the motion of dispersed charged particles through an EF using either direct or alternating current. The use of direct current to move any kind of charged molecule in a uniform EF is termed electrophoresis.…”

Grayscale surface patterning using electrophoretic motion through a heterogeneous hydrogel material

“…The use of electrophoresis to generate patterns within hydrogels has been demonstrated previously; Dai et al [43] used an electric field to drive charged molecules through holes in a glass or plastic mask, which created patterned columns within a hydrogel. Aguilar et al [44] improved this method by using a mask material that was permeable to ions and water, minimizing the impact of the mask on the electric field and enabling patterns to be created through centimeters of hydrogel material.…”