Optimized holographic femtosecond laser patterning method towards rapid integration of high-quality functional devices in microchannels.

Chenchu Zhang,Ze Cai,Dong Wu,Gang Zhao,Peichao Wu,Yanlei Hu,Jiaru Chu,Wenqiang Du,Shenglong Rao,Bing Xu,Jincheng Ni,Koji Sugioka,Zhaoxin Lao,Jiawen Li

doi:10.1038/srep33281

Abstract

Rapid integration of high-quality functional devices in microchannels is in highly demand for miniature lab-on-a-chip applications. This paper demonstrates the embellishment of existing microfluidic devices with integrated micropatterns via femtosecond laser MRAF-based holographic patterning (MHP) microfabrication, which proves two-photon polymerization (TPP) based on spatial light modulator (SLM) to be a rapid and powerful technology for chip functionalization. Optimized mixed region amplitude freedom (MRAF) algorithm has been used to generate high-quality shaped focus field. Base on the optimized parameters, a single-exposure approach is developed to fabricate 200 × 200 μm microstructure arrays in less than 240 ms. Moreover, microtraps, QR code and letters are integrated into a microdevice by the advanced method for particles capture and device identification. These results indicate that such a holographic laser embellishment of microfluidic devices is simple, flexible and easy to access, which has great potential in lab-on-a-chip applications of biological culture, chemical analyses and optofluidic devices.

Highlights

Different fluids[23], micromixer for high efficiency mixing of different fluids[24], microfilter for controllable filtering of particles[25] and center-pass optofluidic microlens array for 100% cell counting[26] into microfluidic channels
Utilizing the smooth patterned focus generated by mixed region amplitude freedom (MRAF) algorithm, we develop a technique termed MRAF-based holographic patterning (MHP) method, to realize rapid integration of microfluidic device with high resolution and high surface quality
After choosing the initial phase of algorithm, iterative Fourier transform algorithms (IFTAs) calculates the light field at the output plane by a fast Fourier transform of the chosen phase combined with incident light amplitude

Summary

Introduction

Different fluids[23], micromixer for high efficiency mixing of different fluids[24], microfilter for controllable filtering of particles[25] and center-pass optofluidic microlens array for 100% cell counting[26] into microfluidic channels. We apply a phase modulated LC-SLM to generate shaped patterns with highly spatially uniform energy by adopting a mixed region amplitude freedom (MRAF) algorithm[37], which has been put forward to realize smooth patterned focus for atom trapping. Utilizing the smooth patterned focus generated by MRAF algorithm, we develop a technique termed MRAF-based holographic patterning (MHP) method, to realize rapid integration of microfluidic device with high resolution and high surface quality. The rectangular light field distribution along the principal optical axis is theoretically simulated by MRAF, whose uniformity is higher than that derived from Gerchburg-Saxton (GS) algorithm This is further verified by fabricating rectangle patterns with MRAF-calculated computer generated holograms (CGHs) in our experiment. The “lab on chip” microdevice integrated with the trap structures is tested with SiO2 particles suspension with diameters of 3.0 μm, 5.0 μm and 10.0 μm in alcohol solution, and the results show that 10.0 μm beads can be completely captured while other two size beads pass successfully

Methods

Results

Conclusion