Microfabrication Techniques for Neuroprostheses

2011 ◽  
pp. 43-58
1994 ◽  
Vol 372 ◽  
Author(s):  
M. M. Farooqui ◽  
A. G. R. Evans

Fabrication of three dimensional micro structures in silicon and silicon related materials is becoming increasingly important for the realisation of micro systems comprising of sensors, actuators, transducers and analytical assemblies. Fabrication of such devices so far has been mostly in form of structures defined by the crystal planes of silicon, or has involved sophisticated technologies such as ion beam machining, replication using LIGA, or micromachining techniques involving a sequence of alignment and etch stages using binary masks. Structures with circular symmetry are of great interest as micro optical components amongst others, and these are not easily amenable to microfabrication techniques commonly employed.


Author(s):  
Karen Chang Yan ◽  
John Sperduto ◽  
Michael Rossini ◽  
Michael Sebok

Microfluidic devices are widely used in biomedical applications owing to their inherent advantages. Microfabrication techniques are common methods for fabricating microfluidic devices, which require specialized equipment. This paper presents a multi-layer construction process for producing microfluidic devices via integrating two accessible fabrication techniques — hydrogel molding, a microfabrication-free method, and electrospinning (ES). The formed microchannels were examined via analyzing micrographs. Preliminary results demonstrate the feasibility of the method and potential for incorporating complex channels and device optimization.


2000 ◽  
Author(s):  
Laurent Dellmann ◽  
Terunobu Akiyama ◽  
Danick Briand ◽  
Sebastien Gautsch ◽  
Olivier T. Guenat ◽  
...  

Biosensors ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 27
Author(s):  
Roselien Vercauteren ◽  
Audrey Leprince ◽  
Jacques Mahillon ◽  
Laurent A. Francis

Porous silicon (PSi) has been widely used as a biosensor in recent years due to its large surface area and its optical properties. Most PSi biosensors consist in close-ended porous layers, and, because of the diffusion-limited infiltration of the analyte, they lack sensitivity and speed of response. In order to overcome these shortcomings, PSi membranes (PSiMs) have been fabricated using electrochemical etching and standard microfabrication techniques. In this work, PSiMs have been used for the optical detection of Bacillus cereus lysate. Before detection, the bacteria are selectively lysed by PlyB221, an endolysin encoded by the bacteriophage Deep-Blue targeting B. cereus. The detection relies on the infiltration of bacterial lysate inside the membrane, which induces a shift of the effective optical thickness. The biosensor was able to detect a B. cereus bacterial lysate, with an initial bacteria concentration of 105 colony forming units per mL (CFU/mL), in only 1 h. This proof-of-concept also illustrates the specificity of the lysis before detection. Not only does this detection platform enable the fast detection of bacteria, but the same technique can be extended to other bacteria using selective lysis, as demonstrated by the detection of Staphylococcus epidermidis, selectively lysed by lysostaphin.


2017 ◽  
Vol 5 (4) ◽  
Author(s):  
S. Debnath ◽  
J. Kundu ◽  
B. Bhattacharyya

To adapt with today's rapidly changing world, fabrication of intricate microparts is becoming an urgent need. Manufacturing of these microparts with stringent requirements necessitates the early adoption of different microfabrication techniques. Wire electrochemical machining (WECM) is such a process which removes excess metal by dissolving it electrochemically. This process can easily generate features downscaled to micron ranges and offers several advantages like the requirement of very simple setup, fabrication of accurate complex microfeatures without undergoing any thermal stress, burr formation, and tool wear, which make it superior from other existing micromachining processes. However, this process is new, and little is known about its applicability and feasibility. Hence, the present work is directed towards developing suitable WECM setup to fabricate microfeatures by introducing proper means for enhancing the mass transport phenomenon. The tungsten tool wire for machining has been in situ etched to a diameter of 23.43 μm by a novel approach for retaining its regular cylindrical form and has been implemented during machining. Moreover, the influences of high duty ratio and applied frequency have been investigated on the corresponding width of the fabricated microslits and the experimental results have been represented graphically where the minimum width of the microslit is obtained as 44.85 μm. Furthermore, mathematical modeling has been developed to correlate duty ratio and applied frequency with generated slit width. Additionally, the mathematical modeling has been validated with practical results and complex stepped type microfeatures have been generated to establish process suitability.


Author(s):  
Naoki Yanagisawa ◽  
Elena Kozgunova ◽  
Guido Grossmann ◽  
Anja Geitmann ◽  
Tetsuya Higashiyama

Abstract Many plant processes occur in the context of and in interaction with a surrounding matrix such as soil (e.g. root growth and root–microbe interactions) or surrounding tissues (e.g. pollen tube growth through the pistil), making it difficult to study them with high-resolution optical microscopy. Over the past decade, microfabrication techniques have been developed to produce experimental systems that allow researchers to examine cell behavior in microstructured environments that mimic geometrical, physical and/or chemical aspects of the natural growth matrices and that cannot be generated using traditional agar plate assays. These microfabricated environments offer considerable design flexibility as well as the transparency required for high-resolution, light-based microscopy. In addition, microfluidic platforms have been used for various types of bioassays, including cellular force assays, chemoattraction assays, and electrotropism assays. Here, we review the recent use of microfluidic devices to study plant cells and organs, including plant roots, root hairs, moss protonemata, and pollen tubes. The increasing adoption of microfabrication techniques by the plant science community may transform our approaches to investigating how individual plant cells sense and respond to changes in the physical and chemical environment.


2008 ◽  
Author(s):  
M. Ams ◽  
D. Little ◽  
R. J. Williams ◽  
G. D. Marshall ◽  
P. Dekker ◽  
...  

2020 ◽  
Vol 8 (11) ◽  
pp. 1841
Author(s):  
Stéphane Pinck ◽  
Lucila Martínez Ostormujof ◽  
Sébastien Teychené ◽  
Benjamin Erable

It is the ambition of many researchers to finally be able to close in on the fundamental, coupled phenomena that occur during the formation and expression of electrocatalytic activity in electroactive biofilms. It is because of this desire to understand that bioelectrochemical systems (BESs) have been miniaturized into microBES by taking advantage of the worldwide development of microfluidics. Microfluidics tools applied to bioelectrochemistry permit even more fundamental studies of interactions and coupled phenomena occurring at the microscale, thanks, in particular, to the concomitant combination of electroanalysis, spectroscopic analytical techniques and real-time microscopy that is now possible. The analytical microsystem is therefore much better suited to the monitoring, not only of electroactive biofilm formation but also of the expression and disentangling of extracellular electron transfer (EET) catalytic mechanisms. This article reviews the details of the configurations of microfluidic BESs designed for selected objectives and their microfabrication techniques. Because the aim is to manipulate microvolumes and due to the high modularity of the experimental systems, the interfacial conditions between electrodes and electrolytes are perfectly controlled in terms of physicochemistry (pH, nutrients, chemical effectors, etc.) and hydrodynamics (shear, material transport, etc.). Most of the theoretical advances have been obtained thanks to work carried out using models of electroactive bacteria monocultures, mainly to simplify biological investigation systems. However, a huge virgin field of investigation still remains to be explored by taking advantage of the capacities of microfluidic BESs regarding the complexity and interactions of mixed electroactive biofilms.


Author(s):  
Richard Galos ◽  
Xin Li

Electrical Impedance Measurement of PZT Nanofiber sensors are performed and material properties including resistivity and dielectric constant are derived from the measurements. Nanofibers formed by electro-spinning with diameters ranging from 10 to 150 nm were collected and integrated into sensors using microfabrication techniques. The nanosensor impedance was extremely high at low frequencies and special matching circuitry was fabricated to detect output. The resulting impedance measurements are also compared with those of individual nanofibers that were tested using Scanning Conductive Microscopy (SCM) and Conductive AFM.


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