High Resolution Separation of Proteins in a Polymeric Micro-Fluidic Chip

2003 ◽  
Author(s):  
Keisuke Horiuchi ◽  
Prashanta Dutta ◽  
Huanchun Cui ◽  
Cornelius F. Ivory
Keyword(s):  
High Resolution ◽  
Mass Production ◽  
Soft Lithography ◽  
Fluorescent Proteins ◽  
Three Dimensional ◽  
Peak Capacity ◽  
Microfluidic Chips ◽  
Sharp Edges ◽  
Separation Of Proteins ◽  
Long Channel

An integrated micro-fluidic chip has been developed using Poly-di-methyl siloxane (PDMS) to separate proteins by isoelectric focusing (IEF). Soft lithography techniques, which offer rapid prototyping, easy multilayer fabrication, mass production capability and biocompatibility, were utilized to fabricate various parts of the micro-fluidic chip. Separately molded PDMS layers were bonded together to form three-dimensional microfluidic chips. The microfluidic chips were prepared for IEF by conditioning the channel with 1 M NaOH and then loading it with a solution of fluorescent proteins made using 0.4% MC, 4% broad-range ampholyte and 0.018 mg/ml protein in 18 MOhm water. Relatively large reservoirs on the acidic and basic ends of the channel were filled with anolyte (50 mM phosphoric acid) and catholyte (50 mM sodium hydroxide), respectively, and then current was applied along the axis of the channel until one or more bands of protein focused, usually in just a few minutes even at relatively low voltages. The focused bands were generally well-formed with sharp edges and were less than 100 microns across yielding a putative peak capacity in excess of 100 peaks in a 2-cm long channel.

Band Deformation at a T-Junction While Electrofocusing in a Dog-Leg Microchannel

2004 ◽  
Author(s):  
Keisuke Horiuchi ◽  
Prashanta Dutta ◽  
Huanchun Cui ◽  
Cornelius F. Ivory
Keyword(s):  
Soft Lithography ◽  
Three Dimensional ◽  
Methyl Cellulose ◽  
Microfluidic Chips ◽  
Separation And Purification ◽  
Sharp Edges ◽  
Viscous Polymer ◽  
Band Deformation ◽  
On Chip ◽  
Long Channel

On-chip isoelectric focusing (IEF) has been performed in both straight and dog-leg microchannels. Three-dimensional microfluidic chips were fabricated on poly di-methyl-siloxane (PDMS) using soft lithography and multilayer bonding techniques. Plasma oxidized PDMS channel surfaces were dynamically coated with methyl cellulose to discourage electroosmotic flow during separation and purification processes. In a straight microchannel, IEF was completed within 5 minutes at an applied electric field strength of 50 V/cm using broad range ampholytes. The focused bands were generally well-formed with sharp edges and were less than 100 microns across yielding a putative peak capacity in excess of 100 peaks in a 2-cm long channel. However, the conventional IEF protocol shifts the focused bands toward the cathodic well. This cathodic drift can be effectively minimized by placing highly viscous polymer solutions in the electrode reservoirs. In dog-leg microchannels, initially well formed focused band dispersed at the Tee-channel junction, but refocused at the dog-leg channels with relatively lower resolution.

scholarly journals Rapid and Inexpensive Fabrication of Multi-Depth Microfluidic Device using High-Resolution LCD Stereolithographic 3D Printing

2019 ◽  
Vol 3 (1) ◽  
pp. 26 ◽  
Author(s):  
Mohamed Mohamed ◽  
Hitendra Kumar ◽  
Zongjie Wang ◽  
Nicholas Martin ◽  
Barry Mills ◽  
...  
Keyword(s):  
High Resolution ◽  
3D Printing ◽  
Soft Lithography ◽  
Liquid Crystal Display ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Single Step ◽  
Droplet Generator ◽  
Rapid Fabrication ◽  
Printing System

With the dramatic increment of complexity, more microfluidic devices require 3D structures, such as multi-depth and -layer channels. The traditional multi-step photolithography is time-consuming and labor-intensive and also requires precise alignment during the fabrication of microfluidic devices. Here, we present an inexpensive, single-step, and rapid fabrication method for multi-depth microfluidic devices using a high-resolution liquid crystal display (LCD) stereolithographic (SLA) three-dimensional (3D) printing system. With the pixel size down to 47.25 μm, the feature resolutions in the horizontal and vertical directions are 150 μm and 50 μm, respectively. The multi-depth molds were successfully printed at the same time and the multi-depth features were transferred properly to the polydimethylsiloxane (PDMS) having multi-depth channels via soft lithography. A flow-focusing droplet generator with a multi-depth channel was fabricated using the presented 3D printing method. Experimental results show that the multi-depth channel could manipulate the morphology and size of droplets, which is desired for many engineering applications. Taken together, LCD SLA 3D printing is an excellent alternative method to the multi-step photolithography for the fabrication of multi-depth microfluidic devices. Taking the advantages of its controllability, cost-effectiveness, and acceptable resolution, LCD SLA 3D printing can have a great potential to fabricate 3D microfluidic devices.

scholarly journals A combined 3D printing/CNC micro-milling method to fabricate a large-scale microfluidic device with the small size 3D architectures: an application for tumor spheroid production

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ebrahim Behroodi ◽  
Hamid Latifi ◽  
Zeinab Bagheri ◽  
Esra Ermis ◽  
Shabnam Roshani ◽  
...  
Keyword(s):  
High Resolution ◽  
3D Printing ◽  
Large Scale ◽  
Three Dimensional ◽  
Micro Milling ◽  
Tumor Spheroid ◽  
Microfluidic Chips ◽  
Difficult Time ◽  
Micro Channels ◽  
Milling Method

AbstractThe fabrication of a large-scale microfluidic mold with 3D microstructures for manufacturing of the conical microwell chip using a combined projection micro-stereolithography (PµSL) 3D printing/CNC micro-milling method for tumor spheroid formation is presented. The PµSL technique is known as the most promising method of manufacturing microfluidic chips due to the possibility of creating complex three-dimensional microstructures with high resolution in the range of several micrometers. The purpose of applying the proposed method is to investigate the influence of microwell depths on the formation of tumor spheroids. In the conventional methods, the construction of three-dimensional microstructures and multi-height chips is difficult, time-consuming, and is performed using a multi-step lithography process. Microwell depth is an essential parameter for microwell design since it directly affects the shear stress of the fluid flow and the diffusion of nutrients, respiratory gases, and growth factors. In this study, a chip was made with microwells of different depth varying from 100 to 500 µm. The mold of the microwell section is printed by the lab-made PµSL printer with 6 and 1 µm lateral and vertical resolutions. Other parts of the mold, such as the main chamber and micro-channels, were manufactured using the CNC micro-milling method. Finally, different parts of the master mold were assembled and used for PDMS casting. The proposed technique drastically simplifies the fabrication and rapid prototyping of large-scale microfluidic devices with high-resolution microstructures by combining 3D printing with the CNC micro-milling method.

scholarly journals 3D Nanofabrication inside rapid prototyped microfluidic channels showcased by wet-spinning of single micrometre fibres

2019 ◽  
Author(s):  
Matthias Wessling
Keyword(s):  
Soft Lithography ◽  
Three Dimensional ◽  
Free Form ◽  
Wet Spinning ◽  
Microfluidic Channels ◽  
Microfluidic Chips ◽  
Single Digit ◽  
Manufacturing Method ◽  
Multiphoton Lithography ◽  
Fibre Spinning

Microfluidics is an established multidisciplinary research domain with widespread applications in the fields of medicine, biotechnology and engineering. Conventional production methods of microfluidic chips have been limited to planar structures, preventing the exploitation of truly three-dimensional architectures for applications such as multi-phase droplet preparation or wet-phase fibre spinning. Here the challenge of nanofabrication inside a microfluidic chip is tackled for the showcase of a spider-inspired spinneret. Multiphoton lithography, an additive manufacturing method, was used to produce free-form microfluidic masters, subsequently replicated by soft lithography. Into the resulting microfluidic device, a three-dimensional spider-inspired spinneret was directly fabricated in-chip via multiphoton lithography. Applying this unprecedented fabrication strategy, the to date smallest printed spinneret nozzle is produced. This spinneret resides tightly sealed, connecting it to the macroscopic world. Its functionality is demonstrated by wet-spinning of single-digit micron fibres through a polyacrylonitrile coagulation process induced by a water sheath layer. The methodology developed here demonstrates fabrication strategies to interface complex architectures into classical microfluidic platforms. Using multiphoton lithography for in-chip fabrication adopts a high spatial resolution technology for improving geometry and thus flow control inside microfluidic chips. The showcased fabrication methodology is generic and will be applicable to multiple challenges in fluid control and beyond.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Electron crystallographic determination of the 3-D structure of staurolite at atomic resolution

1991 ◽  
Vol 49 ◽  
pp. 540-541
Author(s):  
Kenneth H. Downing ◽  
Hu Meisheng ◽  
Hans-Rudolf Went ◽  
Michael A. O'Keefe
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Atomic Resolution ◽  
Dimensional Structure ◽  
Structure Information ◽  
Resolution Electron ◽  
Scattering Effects ◽  
High Resolution Images ◽  
Effects Of Radiation

With current advances in electron microscope design, high resolution electron microscopy has become routine, and point resolutions of better than 2Å have been obtained in images of many inorganic crystals. Although this resolution is sufficient to resolve interatomic spacings, interpretation generally requires comparison of experimental images with calculations. Since the images are two-dimensional representations of projections of the full three-dimensional structure, information is invariably lost in the overlapping images of atoms at various heights. The technique of electron crystallography, in which information from several views of a crystal is combined, has been developed to obtain three-dimensional information on proteins. The resolution in images of proteins is severely limited by effects of radiation damage. In principle, atomic-resolution, 3D reconstructions should be obtainable from specimens that are resistant to damage. The most serious problem would appear to be in obtaining high-resolution images from areas that are thin enough that dynamical scattering effects can be ignored.

Three-Dimensional Immunoelectron Microscopy of Yeast Cells by a New High-Resolution Replica Method

1985 ◽  
Vol 43 ◽  
pp. 562-563
Author(s):  
Hirano T. ◽  
M. Yamaguchi ◽  
M. Hayashi ◽  
Y. Sekiguchi ◽  
A. Tanaka
Keyword(s):  
High Resolution ◽  
Plasma Polymerization ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Replica Method ◽  
Yeast Cells ◽  
Dynamic Aspect ◽  
Replica Technique ◽  
Gaseous Hydrocarbon ◽  
Transmission Electron

A plasma polymerization film replica method is a new high resolution replica technique devised by Tanaka et al. in 1978. It has been developed for investigation of the three dimensional ultrastructure in biological or nonbiological specimens with the transmission electron microscope. This method is based on direct observation of the single-stage replica film, which was obtained by directly coating on the specimen surface. A plasma polymerization film was deposited by gaseous hydrocarbon monomer in a glow discharge.The present study further developed the freeze fracture method by means of a plasma polymerization film produces a three dimensional replica of chemically untreated cells and provides a clear evidence of fine structure of the yeast plasma membrane, especially the dynamic aspect of the structure of invagination (Figure 1).

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