Fabrication of three-dimensional microarray structures by controlling the thickness and elasticity of poly(dimethylsiloxane) membrane

Abstract

In this paper, we propose a method to construct three-dimensional curved microstructures with easy control of the size, position and shape, by exploiting the elasticity of poly(dimethylsiloxane) (PDMS) membranes and basic physics. For this end, we developed the method to handle thin PDMS membrane safely, and to replicate PDMS microstructure from the PDMS mold. Using this method, we demonstrated two potential applications: (1) the use of concave well for the formation of embryoid body (EB) to differentiate into neuronal cells, and (2) the fabrication of SU-8 and hydrogel microparticles having diverse curved shapes. The curved structures were successfully fabricated with simple process, and EBs were formed in the concave well and differentiated into the neuronal cells. Microparticles with diverse shapes were fabricated from a range of materials for potential use as drug carrier and pH responsive micro-actuator elements.

Cryo‐preservation for the repeated use of a PDMS prepolymer

“…Three types of master mold were used to test whether the cryo‐preserved PDMS prepolymer could faithfully replicate master molds having (1) cylindrical wells 400 μm in diameter and 400 μm in depth; (2) rectangular channels 400 μm in height, 1000 μm in width, and 10 mm in length; and (3) a curved structure (concave). The rectangular and cylindrical master molds were fabricated using a standard SU‐8 based patterning process, and the concave master mold was fabricated by deflecting a thin PDMS layer, as described previously . Nonpreserved PDMS prepolymer, a cryo‐preserved PDMS prepolymer at −20 and −80°C, and a PDMS prepolymer submitted to repeated cryo‐preservation cycles (at −20°C) were poured over the three types of master mold, and the replicated PDMS structures were compared.…”

“…Polydimethylsiloxane (PDMS, Sylgard 184 Silicone Elastomer KIT, Dow Corning) is a silicon‐based organic polymer and is one of most popular materials for creating microfluidic channels, elastic stamps, and flexible electronics . PDMS displays several advantages including optical transparency, gas permeability, and biocompatibility, and such properties facilitate its extensive application in the biological and medical fields . The typical process to construct the PDMS microfluidic channels is the preparation of master mold, PDMS replication from a master mold and bonding.…”

Locally Controlled Diffusive Release of Bone Morphogenetic Protein-2 Using Micropatterned Gelatin Methacrylate Hydrogel Carriers

“…For fabricating a PDMS (Dow Corning, MI, USA)based concave micromold using a replication process, a well-defined photo-lithography method was used with the photosensitive epoxy resin (SU-8, Micro-Chem, MA, USA) 51,52 . A hemispheric SU-8 polymeric convex master mold, which commonly uses an epoxy-based negative photoresist according to a published protocol, was used 51 . Briefly, to make a master mold, a perforated SU-8 shadow mask layer with arrayed holes (diameter: 250 μm) was designed.…”

A Simple Aspect Ratio Dependent Method of Patterning Microwells for Selective Cell Attachment

“…Knowledge of changes in cell morphology, mechanics, and mobility in response to geometrical cues and topological stimuli is important for understanding normal and pathological cell development [3]. Microfabrication provides unique in vitro approaches to recapitulating in vivo conditions due to the ability to precisely control the cellular microenvironment [4, 5]. Microwell arrays have emerged as robust alternatives to traditional 2-D cell culture substrates as they are relatively simple and compatible with existing laboratory techniques and instrumentation [6, 7].…”