On-Chip Trapping and Characterization of Cryptosporidium Using Surface Coated ITO-PDMS Bonded Chips

2011 ◽  
Vol 254 ◽  
pp. 191-194
Author(s):  
Harikrishnan Narayanan Unni ◽  
Deny Hartono ◽  
Kian Meng Lim
Keyword(s):  
Cryptosporidium Oocyst ◽  
Rapid Identification ◽  
Channel Height ◽  
Cell Trapping ◽  
Cell Compartments ◽  
Silane Coating ◽  
Ito Glass ◽  
Cryptosporidium Oocysts ◽  
On Chip

Dielectrophoresis has been shown to have significant potential for the characterization of cells and could become an efficient tool for rapid identification and assessment of microorganisms. The present work is focused on the trapping and characterization of Cryptosporidium pathogen using a microfluidic chip fabricated through a simple, effective bonding of surface coated ITO glass and PDMS. Lithographically patterned ITO glass plates were coated with an alkoxysilane solution DMOAP (N, N – dimethyl -N- octadecyl-3-aminopropyltrimethoxysilyl chloride) prior to bonding with PDMS microchannels. The silane coating was found to enhance the bonding between ITO and PDMS and reduce cell adhesion on the electrodes. Cryptosporidium oocysts, which are 2-4 microns in size and nearly spherical in shape represent the preliminary stage of cell development. The dielectrophoretic transport of cells is dependent on electrical properties such as permittivity and conductivity of the cells. Computational simulations were performed in order to study the effects of channel height, buffer conductivity and applied voltage on the flow and cell transport inside the DEP chip and facilitate effective cell trapping. Videomicroscopic experiments were performed using the fabricated device and the real part of Clausius-Mossotti factor of the cells was estimated from values of critical voltages of particle trapping (corresponding to various field frequencies) at the electrodes. The dielectric properties of the cell compartments (cytoplasm and membrane) were calculated based on a single shell model of the Cryptosporidium oocyst cell.

scholarly journals Use of Oxidative Stress Responses to Determine the Efficacy of Inactivation Treatments on Cryptosporidium Oocysts

2021 ◽  
Vol 9 (7) ◽  
pp. 1463
Author(s):  
Tamirat Tefera Temesgen ◽  
Kristoffer Relling Tysnes ◽  
Lucy Jane Robertson
Keyword(s):  
Oxidative Stress ◽  
Stress Responses ◽  
Target Genes ◽  
Cryptosporidium Oocyst ◽  
Drinking Water Treatment ◽  
Proof Of Concept ◽  
Environmental Matrices ◽  
Oocyst Wall ◽  
Novel Approach ◽  
Cryptosporidium Oocysts

Cryptosporidium oocysts are known for being very robust, and their prolonged survival in the environment has resulted in outbreaks of cryptosporidiosis associated with the consumption of contaminated water or food. Although inactivation methods used for drinking water treatment, such as UV irradiation, can inactivate Cryptosporidium oocysts, they are not necessarily suitable for use with other environmental matrices, such as food. In order to identify alternative ways to inactivate Cryptosporidium oocysts, improved methods for viability assessment are needed. Here we describe a proof of concept for a novel approach for determining how effective inactivation treatments are at killing pathogens, such as the parasite Cryptosporidium. RNA sequencing was used to identify potential up-regulated target genes induced by oxidative stress, and a reverse transcription quantitative PCR (RT-qPCR) protocol was developed to assess their up-regulation following exposure to different induction treatments. Accordingly, RT-qPCR protocols targeting thioredoxin and Cryptosporidium oocyst wall protein 7 (COWP7) genes were evaluated on mixtures of viable and inactivated oocysts, and on oocysts subjected to various potential inactivation treatments such as freezing and chlorination. The results from the present proof-of-concept experiments indicate that this could be a useful tool in efforts towards assessing potential technologies for inactivating Cryptosporidium in different environmental matrices. Furthermore, this approach could also be used for similar investigations with other pathogens.

scholarly journals Emerging Options for the Diagnosis of Bacterial Infections and the Characterization of Antimicrobial Resistance

2021 ◽  
Vol 22 (1) ◽  
pp. 456
Author(s):  
Simone Rentschler ◽  
Lars Kaiser ◽  
Hans-Peter Deigner
Keyword(s):  
Antimicrobial Resistance ◽  
Bacterial Infections ◽  
Point Of Care ◽  
Rapid Identification ◽  
Adequate Treatment ◽  
Resistance Patterns ◽  
Detection And Diagnosis ◽  
Patient Prognosis ◽  
Point Of Care Detection

Precise and rapid identification and characterization of pathogens and antimicrobial resistance patterns are critical for the adequate treatment of infections, which represent an increasing problem in intensive care medicine. The current situation remains far from satisfactory in terms of turnaround times and overall efficacy. Application of an ineffective antimicrobial agent or the unnecessary use of broad-spectrum antibiotics worsens the patient prognosis and further accelerates the generation of resistant mutants. Here, we provide an overview that includes an evaluation and comparison of existing tools used to diagnose bacterial infections, together with a consideration of the underlying molecular principles and technologies. Special emphasis is placed on emerging developments that may lead to significant improvements in point of care detection and diagnosis of multi-resistant pathogens, and new directions that may be used to guide antibiotic therapy.

scholarly journals Extended lubrication theory: improved estimates of flow in channels with variable geometry

2017 ◽  
Vol 473 (2206) ◽  
pp. 20170234 ◽  
Author(s):  
Behrouz Tavakol ◽  
Guillaume Froehlicher ◽  
Douglas P. Holmes ◽  
Howard A. Stone
Keyword(s):  
Stokes Equations ◽  
Perturbation Expansion ◽  
Accurate Estimate ◽  
Higher Order ◽  
Lubrication Theory ◽  
Channel Height ◽  
Fluid Films ◽  
Flow Characterization ◽  
Systematic Perturbation

Lubrication theory is broadly applicable to the flow characterization of thin fluid films and the motion of particles near surfaces. We offer an extension to lubrication theory by starting with Stokes equations and considering higher-order terms in a systematic perturbation expansion to describe the fluid flow in a channel with features of a modest aspect ratio. Experimental results qualitatively confirm the higher-order analytical solutions, while numerical results are in very good agreement with the higher-order analytical results. We show that the extended lubrication theory is a robust tool for an accurate estimate of pressure drop in channels with shape changes on the order of the channel height, accounting for both smooth and sharp changes in geometry.

scholarly journals Demonstration of an integrated nanophotonic chip-scale alkali vapor magnetometer using inverse design

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yoel Sebbag ◽  
Eliran Talker ◽  
Alex Naiman ◽  
Yefim Barash ◽  
Uriel Levy
Keyword(s):  
Spatial Resolution ◽  
Near Field ◽  
Computer Assisted ◽  
Experimental Characterization ◽  
Optical Isolation ◽  
New Concepts ◽  
On Chip ◽  
The Cost ◽  
Micrometer Scale

AbstractRecently, there has been growing interest in the miniaturization and integration of atomic-based quantum technologies. In addition to the obvious advantages brought by such integration in facilitating mass production, reducing the footprint, and reducing the cost, the flexibility offered by on-chip integration enables the development of new concepts and capabilities. In particular, recent advanced techniques based on computer-assisted optimization algorithms enable the development of newly engineered photonic structures with unconventional functionalities. Taking this concept further, we hereby demonstrate the design, fabrication, and experimental characterization of an integrated nanophotonic-atomic chip magnetometer based on alkali vapor with a micrometer-scale spatial resolution and a magnetic sensitivity of 700 pT/√Hz. The presented platform paves the way for future applications using integrated photonic–atomic chips, including high-spatial-resolution magnetometry, near-field vectorial imaging, magnetically induced switching, and optical isolation.

Determination of the Recovery Efficiency of Cryptosporidium Oocysts and Giardia Cysts from Seeded Bivalve Mollusks

2013 ◽  
Vol 76 (1) ◽  
pp. 93-98 ◽  
Author(s):  
FRANCISKA M. SCHETS ◽  
HAROLD H. J. L. van den BERG ◽  
ANA MARIA de RODA HUSMAN
Keyword(s):  
Quantitative Assessment ◽  
Intestinal Parasites ◽  
Cryptosporidium Oocyst ◽  
Immunomagnetic Separation ◽  
Giardia Cyst ◽  
Bivalve Mollusks ◽  
Recovery Efficiency ◽  
Risk Of Infection ◽  
Cryptosporidium Oocysts

The intestinal parasites Cryptosporidium and Giardia are transmitted by water and food and cause human gastroenteritis. Filter-feeding bivalve mollusks, such as oysters and mussels, filter large volumes of water and thus concentrate such pathogens, which makes these bivalves potential vectors of disease. To assess the risk of infection from consumption of contaminated bivalves, parasite numbers and parasite recovery data are required. A modified immunomagnetic separation (IMS) procedure was used to determine Cryptosporidium oocyst and Giardia cyst numbers in individually homogenized oysters (Crassostrea gigas) and mussels (Mytilus edulis). About 12% of the commercial bivalves were positive, with low (oo)cyst numbers per specimen. The recovery efficiency of the IMS procedure was systematically evaluated. Experiments included seeding of homogenized bivalves and whole animals with 100 to 1,000 (oo)cysts. Both seeding procedures yielded highly variable recovery rates. Median Cryptosporidium recoveries were 7.9 to 21% in oysters and 62% in mussels. Median Giardia recoveries were 10 to 25% in oysters and 110% in mussels. Giardia recovery was significantly higher than Cryptosporidium recovery. (Oo)cysts were less efficiently recovered from seeded whole animals than from seeded homogenates, with median Cryptosporidium recoveries of 5.3% in oysters and 45% in mussels and median Giardia recoveries of 4.0% in oysters and 82% in mussels. Both bivalve homogenate seeding and whole animal seeding yielded higher (oo)cyst recovery in mussels than in oysters, likely because of the presence of less shellfish tissue in IMS when analyzing the smaller mussels compared with the larger oysters, resulting in more efficient (oo)cyst extraction. The data generated in this study may be used in the quantitative assessment of the risk of infection with Cryptosporidium or Giardia associated with the consumption of raw bivalve mollusks. This information may be used for making risk management decisions.

Cryptosporidium oocyst shedding in buffalo calves in Haryana: A case study

2018 ◽  
Author(s):  
Krutanjali Swain ◽  
Abhilash Routray ◽  
Saraswat Sahoo and Subha Ganguly
Keyword(s):  
Cryptosporidium Oocyst ◽  
Buffalo Calves ◽  
Concentration Technique ◽  
Cryptosporidium Oocysts ◽  
Oil Immersion ◽  
Neonatal Diarrhoea ◽  
Conventional Microscopy ◽  
Animal Sciences ◽  
Acid Fast Staining

Bovine cryptosporidiosisis primarily associated with neonatal diarrhoea with higher morbidity than mortality in young calves till they attain immunological maturity. The present investigation relates to a report on the shedding of Cryptosporidium oocyst in two buffalo calves of buffalo farm, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar from 1st days up to 3 month of age at 15 days interval using simple conventional microscopy. By using formol-ether concentration technique followed by modified Ziehl-Neelsen (ZN) acid fast staining, Cryptosporidium oocysts were concentrated and identified. The Cryptosporidium oocysts appeared as reddish pink coloured bodies against a bluish/greenish coloured background at oil immersion using ZN staining kit. The maximum oocyst shedding was observed (2.3 oocyst / field) during 16 to 30 days of age. The oocyst shedding gradually decreased with increase in age afterwards clearly indicating the disease of young buffalo calves.

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