Capillary Flow Layer-by-Layer: A Microfluidic Platform for the High-Throughput Assembly and Screening of Nanolayered Film Libraries

Abstract

Layer-by-layer (LbL) assembly is a powerful tool with increasing real world applications in energy, biomaterials, active surfaces, and membranes; however, the current state of the art requires individual sample construction using large quantities of material. Here we describe a technique using capillary flow within a microfluidic device to drive high-throughput assembly of LbL film libraries. This capillary flow layer-by-layer (CF-LbL) method significantly reduces material waste, improves quality control, and expands the potential applications of LbL into new research spaces. The method can be operated as a simple lab benchtop apparatus or combined with liquid-handling robotics to extend the library size. Here we describe and demonstrate the technique and establish its ability to recreate and expand on the known literature for film growth and morphology. We use the same platform to assay biological properties such as cell adhesion and proliferation and ultimately provide an example of the use of this approach to identify LbL films for surface-based DNA transfection of commonly used cell types.

High Throughput Layer-by-Layer Films for Extracting Film Forming Parameters and Modulating Film Interactions with Cells

“…27,31 These high-throughput methods capable of LbL film synthesis have been leveraged to facilitate systematic investigations between a variety of cell types and LbL films so as to optimize material properties for specific cellular interactions. 27,31 For example, gradient LbL films systematically generated in a combinatorial manner can be used to rapidly assess polyelectrolyte pairs for their interactions with cells. 31 More recently, LbL film libraries were fabricated using a novel method making use of small volumes of materials with multiple independent microfluidic channels (capillary flow-LbL) to generate thin films to screen a number 4 of cell-material interactions; in this case, optimization of in vitro DNA transfection was demonstrated.…”

Layer-by-Layer Assembly of PEDOT:PSS and WO3 Nanoparticles: Enhanced Electrochromic Coloration Efficiency and Mechanism Studies by Scanning Electrochemical Microscopy

“…Various nanostructures, such as nanoparticles, nanotubes and nanosheets, can be used as building blocks of LBL-assembled thin films [14,16]. Compared with other thin-film fabrication methods, such as electrodeposition, the LBL process allows precise control over the deposition of each component from solution [17,18] and hence is very useful for fabrication of hybrid films with tailored morphologies for mechanism studies. A significant advantage of LBL assembly process for the fabrication of electrochromic thin films is the ease in incorporation of EC materials with polyelectrolyte, which can act as ionic conductors to aid insertion/extraction of ions into/ from the electrochromic materials [19,20].…”

Gene delivery using dendrimer/pDNA complexes immobilized in electrospun fibers using the Layer-by-Layer technique

“…29 By using the LbL assembly approach, a broad range of materials including polymers, nanoparticles, and biomolecules are able to be assembled onto substrates of varying geometry (e.g., planar surfaces, colloids, and fibers, etc.) to form functional nanostructured materials.…”