Femtosecond Laser Direct Write Integration of Multi-Protein Patterns and 3D Microstructures into 3D Glass Microfluidic Devices

Daniela Serien,Koji Sugioka,Atsushi Miyawaki,Katsumi Midorikawa,Hiroyuki Kawano

doi:10.3390/app8020147

Abstract

Microfluidic devices and biochips offer miniaturized laboratories for the separation, reaction, and analysis of biochemical materials with high sensitivity and low reagent consumption. The integration of functional or biomimetic elements further functionalizes microfluidic devices for more complex biological studies. The recently proposed ship-in-a-bottle integration based on laser direct writing allows the construction of microcomponents made of photosensitive polymer inside closed microfluidic structures. Here, we expand this technology to integrate proteinaceous two-dimensional (2D) and three-dimensional (3D) microstructures with the aid of photo-induced cross-linking into glass microchannels. The concept is demonstrated with bovine serum albumin and enhanced green fluorescent protein, each mixed with photoinitiator (Sodium 4-[2-(4-Morpholino) benzoyl-2-dimethylamino] butylbenzenesulfonate). Unlike the polymer integration, fabrication over the entire channel cross-section is challenging. Two proteins are integrated into the same channel to demonstrate multi-protein patterning. Using 50% w/w glycerol solvent instead of 100% water achieves almost the same fabrication resolution for in-channel fabrication as on-surface fabrication due to the improved refractive index matching, enabling the fabrication of 3D microstructures. A glycerol-water solvent also reduces the risk of drying samples. We believe this technology can integrate diverse proteins to contribute to the versatility of microfluidics.

Highlights

Microfluidics is increasingly influential to academia and industry in diverse fields including biology, chemistry, medicine, foods, energy, environment, etc. because of the advantageously small footprint sizes, high sensitivity, feature diversity, and compartmentalization [1]
We further demonstrate the micropatterning of multi-proteins two-step integration of enhanced green fluorescent protein (EGFP) and bovine serum albumin (BSA)
We studied feature sizes of line patterns of BSA, and demonstrate multi-protein integration in glass microfluidic channels

Summary

Introduction

Microfluidics is increasingly influential to academia and industry in diverse fields including biology, chemistry, medicine, foods, energy, environment, etc. because of the advantageously small footprint sizes, high sensitivity, feature diversity, and compartmentalization [1]. Microfluidics is increasingly influential to academia and industry in diverse fields including biology, chemistry, medicine, foods, energy, environment, etc. Because of the advantageously small footprint sizes, high sensitivity, feature diversity, and compartmentalization [1]. Feature diversity and compartmentalization allow the fabrication of so-called organ- or body-on-a-chip devices, which recreate organ or bodily functions mimicking appropriate bodily responses on microchips for drug screening [2]. Small footprint sizes allow efficient and complex detection in diagnostics by so-called. Sci. 2018, 8, 147 micro total analysis systems (μ-TAS) [3]. For all of these purposes, microfluidic devices commonly created in glass or polymer are building blocks, and desired functions are integrated to further functionalize them

Methods

Results

Discussion

Conclusion