Improved Laser Manipulation for On-chip Fabricated Microstructures Based on Solution Replacement and Its Application in Single Cell Analysis

Abstract

In this paper, we present the fabrication and assembly of microstructures inside a microfluidic device based on a photocrosslinkable resin and optical tweezers. We also report a method of solution replacement inside the microfluidic channel in order to improve the manipulation performance and apply the assembled microstructures for single cell cultivation. By the illumination of patterned ultraviolet (UV) through a microscope, microstructures of arbitrary shape were fabricated by the photocrosslinkable resin inside a microfluidic channel. Based on the microfluidic channel with both glass and polydimethylsiloxane (PDMS) surfaces, immovable and movable microstructures were fabricated and manipulated. The microstructures were fabricated at the desired places and manipulated by the optical tweezers. A rotational microstructure including a microgear and a rotation axis was assembled and rotated in demonstrating this technique. The improved laser manipulation of microstructures was achieved based on the on-chip solution replacement method. The manipulation speed of the microstructures increased when the viscosity of the solvent decreased. The movement efficiency of the fabricated microstructures inside the lower viscosity solvent was evaluated and compared with those microstructures inside the former high viscosity solvent. A novel cell cage was fabricated and the cultivation of a single yeast cell (w303) was demonstrated in the cell cage, inside the microfluidic device.

On-Chip Construction of Multilayered Hydrogel Microtubes for Engineered Vascular-Like Microstructures

“…In order to demonstrate the capability of the device to fabricate and assemble different microstructures, two solutions mixed with 2 types of particles, respectively, were prepared. The main experimental solution is poly(ethylene glycol) diacrylate (PEGDA), which is a photocrosslinkable hydrogel with good biocompatibility [18,19,43]. The two prepolymer solutions, mixed by PEGDA (molecular weight 700, Sigma Aldrich, St. Louis, MI, USA), and photoinitiator (2%, Irgacure 2959, Ciba Inc., Basel, Switzerland) with two types of fluorescent microbeads (cat #17152, 0.5 μm diameter as Type A solution; cat #18660, 1 μm diameter as Type B solution) (Fluoresbrite ® Polysciences Inc., Warrington, PA, USA), respectively, were prepared prior to the experiments.…”

“…On-chip fabrication, based on photo-crosslinkable hydrogel via UV illumination, is a creative way for immobilizing cells. Such direct encapsulation of cells inside patterned hydrogels provides many advantages including high speed, low cost, and arbitrary shape [17][18][19].…”

Bubble-based assembly of micro-tube with coordinated multiple manipulators

“…1. Their fabrication process is based on the sensitometric characteristic of biocompatible resin referring to [13][14]. We name them as donuts.…”

Dexterous nanomanipulation of 2D hydrogel microstructure for 3D assembly by multi-robot cooperation

“…Our on-chip fabrication method is based on the sensitometric characteristic of the crosslinkable resin, that is, the resin can solidify into expected microstructure by UV light illumination [21][22]. Poly (ethylene glycol) Diacrylate (PEGDA) resin is applied due to its good biocompatibity.…”