An Integrated Microfluidic Device for the Continuous Sampling and Analysis of Biological Fluids

2001 ◽  
Author(s):  
Jeffrey D. Zahn ◽  
Ajay A. Deshmukh ◽  
Alexandros P. Papavasiliou ◽  
Albert P. Pisano ◽  
Dorian Liepmann
Keyword(s):  
Molecular Weight ◽  
Chemical Sensor ◽  
Biological Fluids ◽  
Microfluidic System ◽  
Integrated Sensor ◽  
Continuous Sampling ◽  
Positive Displacement ◽  
Chip Flow ◽  
Large Molecular Weight ◽  
On Chip

Abstract Enzyme based biosensors suffer from loss of activity and sensitivity. One major reason is due to large molecular weight proteins adsorbing on the surface of the sensor. These proteins affect sensor signal stability and disrupt enzyme function. Thus, one fruitful way to minimize the loss of sensor activity is to filter out large molecular weight compounds before they come in contact with the enzyme based biosensor. Further, the removal of free protein from biological solution helps to increase sensor accuracy and lifetime. Therefore, a microdialysis microneedle is introduced that is capable of excluding large MW compounds based on size. These microneedles have been integrated into a planar microfluidic system capable of sampling and analyzing biological solutions. The integrated microfluidic system includes the assembly of microneedles with on-chip flow channels and electronics together with previously designed positive displacement micropumps, microvalves and a planar electro-chemical sensor for biological detection. Multichannel fluidic control for biological sampling, sensor cleansing and recalibration is demonstrated with integrated sensor operation.

Closed-loop feedback control of microfluidic cell manipulation via deep-learning integrated sensor networks

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Ningquan Wang ◽  
Ruxiu Liu ◽  
Norh Asmare ◽  
Chia-Heng Chu ◽  
Ozgun Civelekoglu ◽  
...  
Keyword(s):  
Deep Learning ◽  
Sensor Networks ◽  
Feedback Control ◽  
Closed Loop ◽  
Microfluidic System ◽  
Cell Manipulation ◽  
Integrated Sensor ◽  
Loop Feedback ◽  
Closed Loop Feedback ◽  
On Chip

An adaptive microfluidic system changing its operational state in real-time based on cell measurements through an on-chip electrical sensor network.

scholarly journals Hydrogel: Preparation, Characterization and Applications

2020 ◽  
Vol 3 (01) ◽  
Author(s):  
Ujjwal Nautiyal ◽  
Nandini Sahu ◽  
Diksha Gupta
Keyword(s):  
Drug Delivery ◽  
Molecular Weight ◽  
Biological Tissue ◽  
Biological Fluids ◽  
Three Dimensional ◽  
Review Article ◽  
Advantages And Disadvantages ◽  
Concise Review ◽  
Large Molecular Weight

This review article is intended to provide an overview of hydrogel as novel vesicular drug delivery system.For the treatment of many diseases large molecular weight proteins are required. These can be available with the availability of Hydrogels. Hydrogels are hydrophilic, three-dimensional networks, which are able to imbibe large amounts of water or biological fluids, and thus resemble, to a large extent, a biological tissue. They are insoluble due to the presence of chemical (tie-points, junctions) and/or physical crosslinks such as entanglements and crystallites. It has focused on to present a concise review on the applications of hydrogels in the pharmaceutical field, hydrogel properties, method of preparation of hydrogel, advantages and disadvantages of hydrogel, characterization of hydrogel.

scholarly journals Study on Functionality and Surface Modification of a Stair-Step Liquid-Triggered Valve for On-Chip Flow Control

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 690
Author(s):  
Xi Chen ◽  
Sihui Chen ◽  
Yi Zhang ◽  
Hui Yang
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Microfluidic System ◽  
Chip Flow ◽  
Initial Stage ◽  
Surface Contact ◽  
Surface Contact Angle ◽  
Fluidic Control ◽  
On Chip ◽  
Micro Systems

Distinctive from other forms of microfluidic system, capillary microfluidics is of great interest in autonomous micro-systems due to its well-engineered fluidic control based on capillary force. As an essential component of fluidic control in capillaric circuits, micro-valves enable sequential fluidic operations by performing actions such as stopping and triggering. In this paper, we present a stair-step liquid-triggered valve; the functionality of the valve and its dependencies on geometry and surface modification are studied. The surface contact angle of the microfabricated valves that are coated by polyethylene glycol (PEG) or (3-Aminopropyl) triethoxysilane (APTES) is evaluated experimentally, and the corresponding reliability of the valve structure is discussed. Moreover, the variation in the surface contact angle over time is investigated, indicating the shelf time of the device. We further discuss the overall fluidic behavior in such capillary valves, which benefits the capillaric circuit designs at the initial stage.

The External Shape of Human γ GI Immunoglobulin from Crystal Sections

1971 ◽  
Vol 29 ◽  
pp. 428-429
Author(s):  
L. W. Labaw
Keyword(s):  
Molecular Weight ◽  
Sodium Phosphate ◽  
Osmium Tetroxide ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray ◽  
Large Molecular Weight ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Crystallographic Axes

Crystals of a human γGl immunoglobulin have the external morphology of diamond shaped prisms. X-ray studies have shown them to be monoclinic, space group C2, with 2 molecules per unit cell. The unit cell dimensions are a = 194.1, b = 91.7, c = 51.6Å, 8 = 102°. The relatively large molecular weight of 151,000 and these unit cell dimensions made this a promising crystal to study in the EM.Crystals similar to those used in the x-ray studies were fixed at 5°C for three weeks in a solution of mother liquor containing 5 x 10-5M sodium phosphate, pH 7.0, and 0.03% glutaraldehyde. They were postfixed with 1% osmium tetroxide for 15 min. and embedded in Maraglas the usual way. Sections were cut perpendicular to the three crystallographic axes. Such a section cut with its plane perpendicular to the z direction is shown in Fig. 1.This projection of the crystal in the z direction shows periodicities in at least four different directions but these are only seen clearly by sighting obliquely along the micrograph.

scholarly journals Design and Manufacturing of a Disposable, Cyclo-Olefin Copolymer, Microfluidic Device for a Biosensor †

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1178 ◽  
Author(s):  
Jorge Prada ◽  
Christina Cordes ◽  
Carsten Harms ◽  
Walter Lang
Keyword(s):  
Microfluidic Device ◽  
Heating Temperature ◽  
Low Cost ◽  
Reaction Chamber ◽  
Microfluidic System ◽  
Heating Process ◽  
Design And Manufacturing ◽  
On Chip ◽  
Working Parameters ◽  
Auto Fluorescence

This contribution outlines the design and manufacturing of a microfluidic device implemented as a biosensor for retrieval and detection of bacteria RNA. The device is fully made of Cyclo-Olefin Copolymer (COC), which features low auto-fluorescence, biocompatibility and manufacturability by hot-embossing. The RNA retrieval was carried on after bacteria heat-lysis by an on-chip micro-heater, whose function was characterized at different working parameters. Carbon resistive temperature sensors were tested, characterized and printed on the biochip sealing film to monitor the heating process. Off-chip and on-chip processed RNA were hybridized with capture probes on the reaction chamber surface and identification was achieved by detection of fluorescence tags. The application of the mentioned techniques and materials proved to allow the development of low-cost, disposable albeit multi-functional microfluidic system, performing heating, temperature sensing and chemical reaction processes in the same device. By proving its effectiveness, this device contributes a reference to show the integration potential of fully thermoplastic devices in biosensor systems.

scholarly journals Classification of Tea Aromas Using Multi-Nanoparticle Based Chemiresistor Arrays

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2547 ◽  
Author(s):  
Tuo Gao ◽  
Yongchen Wang ◽  
Chengwu Zhang ◽  
Zachariah A. Pittman ◽  
Alexandra M. Oliveira ◽  
...  
Keyword(s):  
Chemical Sensor ◽  
Sensor Arrays ◽  
Machine Learning Algorithms ◽  
Single Type ◽  
Multivariate Techniques ◽  
Integrated Sensor ◽  
Resistance Change ◽  
Linear Discriminant ◽  
Lift Off

Nanoparticle based chemical sensor arrays with four types of organo-functionalized gold nanoparticles (AuNPs) were introduced to classify 35 different teas, including black teas, green teas, and herbal teas. Integrated sensor arrays were made using microfabrication methods including photolithography and lift-off processing. Different types of nanoparticle solutions were drop-cast on separate active regions of each sensor chip. Sensor responses, expressed as the ratio of resistance change to baseline resistance (ΔR/R0), were used as input data to discriminate different aromas by statistical analysis using multivariate techniques and machine learning algorithms. With five-fold cross validation, linear discriminant analysis (LDA) gave 99% accuracy for classification of all 35 teas, and 98% and 100% accuracy for separate datasets of herbal teas, and black and green teas, respectively. We find that classification accuracy improves significantly by using multiple types of nanoparticles compared to single type nanoparticle arrays. The results suggest a promising approach to monitor the freshness and quality of tea products.

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