scholarly journals Tangential Flow Microfiltration for Viral Separation and Concentration

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 320 ◽  
Author(s):  
Yi Wang ◽  
Keely Keller ◽  
Xuanhong Cheng
Keyword(s):  
Specific Binding ◽  
Affinity Capture ◽  
Tangential Flow ◽  
Resource Limited ◽  
Hiv Virus ◽  
Physical Deposition ◽  
Consistent Performance ◽  
Set Up ◽  
Comsol Simulation ◽  
Filtration Device

Microfluidic devices that allow biological particle separation and concentration have found wide applications in medical diagnosis. Here we present a viral separation polydimethylsiloxane (PDMS) device that combines tangential flow microfiltration and affinity capture to enrich HIV virus in a single flow-through fashion. The set-up contains a filtration device and a tandem resistance channel. The filtration device consists of two parallel flow channels separated by a polycarbonate nanoporous membrane. The resistance channel, with dimensions design-guided by COMSOL simulation, controls flow permeation through the membrane in the filtration device. A flow-dependent viral capture efficiency is observed, which likely reflects the interplay of several processes, including specific binding of target virus, physical deposition of non-specific particles, and membrane cleaning by shear flow. At the optimal flow rate, nearly 100% of viral particles in the permeate are captured on the membrane with various input viral concentrations. With its easy operation and consistent performance, this microfluidic device provides a potential solution for HIV sample preparation in resource-limited settings.

scholarly journals Fast sorting of CD4+ T cells from whole blood using glass microbubbles

TECHNOLOGY ◽  
2015 ◽  
Vol 03 (01) ◽  
pp. 38-44 ◽  
Author(s):  
Chia-Hsien Hsu ◽  
Chihchen Chen ◽  
Daniel Irimia ◽  
Mehmet Toner
Keyword(s):  
T Cells ◽  
T Lymphocyte ◽  
Whole Blood ◽  
Specific Binding ◽  
Target Cells ◽  
Cd4 Cells ◽  
Specific Antibodies ◽  
Resource Limited ◽  
Aids Diagnosis ◽  
Better Than

The isolation of CD4 positive T lymphocyte (CD4+) from peripheral blood is important for monitoring patients after HIV infection. Here, we demonstrate a fast isolation strategy for CD4+ cells that involves mixing blood and glass microbubbles. After the specific binding of target cells to the microbubbles carrying specific antibodies on their surface, target cells will spontaneously float to the top of the blood vial and can be quickly separated. Using this strategy, we demonstrate that the isolation of CD4+ cells in less than 5 minutes and with better than 90% efficiency. This strategy for cell isolation based on buoyancy and glass microbubbles is quick and inexpensive, minimizes blood handling, does not require magnetic fields, or centrifugation equipment, and could lead to new, efficient strategies for AIDS diagnosis in resource-limited areas.

scholarly journals Affinity Membranes and Monoliths for Protein Purification

Membranes ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
Eleonora Lalli ◽  
Jouciane S. Silva ◽  
Cristiana Boi ◽  
Giulio C. Sarti
Keyword(s):  
Binding Capacity ◽  
Stationary Phases ◽  
Packed Column ◽  
Downstream Processing ◽  
Regenerated Cellulose ◽  
Affinity Capture ◽  
Scale Characterization ◽  
Set Up ◽  
Cellulose Membranes ◽  
Chromatographic Media

Affinity capture represents an important step in downstream processing of proteins and it is conventionally performed through a chromatographic process. The performance of this step highly depends on the type of matrix employed. In particular, resin beads and convective materials, such as membranes and monoliths, are the commonly available supports. The present work deals with non-competitive binding of bovine serum albumin (BSA) on different chromatographic media functionalized with Cibacron Blue F3GA (CB). The aim is to set up the development of the purification process starting from the lab-scale characterization of a commercially available CB resin, regenerated cellulose membranes and polymeric monoliths, functionalized with CB to identify the best option. The performance of the three different chromatographic media is evaluated in terms of BSA binding capacity and productivity. The experimental investigation shows promising results for regenerated cellulose membranes and monoliths, whose performance are comparable with those of the packed column tested. It was demonstrated that the capacity of convective stationary phases does not depend on flow rate, in the range investigated, and that the productivity that can be achieved with membranes is 10 to 20 times higher depending on the initial BSA concentration value, and with monoliths it is approximately twice that of beads, at the same superficial velocity.

scholarly journals SeeTB: A novel alternative to sputum smear microscopy to diagnose tuberculosis in high burden countries

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Vikas Pandey ◽  
Pooja Singh ◽  
Saumya Singh ◽  
Naresh Arora ◽  
Neha Quadir ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
High Signal ◽  
Sputum Smear ◽  
Smear Microscopy ◽  
Fluorescence Excitation ◽  
Case Identification ◽  
Resource Limited ◽  
Realistic Option ◽  
Viscous Polymer ◽  
Set Up

Abstract Microscopy-based tuberculosis (TB) diagnosis i.e. Ziehl-Neelsen screening still remains the primary diagnostic method in resource poor and high TB burden countries, however this method has poor sensitivity (~60%). Bringing three million TB patients who are left undiagnosed under the treatment has been a major focus as part of END-TB strategy across the world. We have developed a portable set-up called ‘SeeTB’ that converts a bright-field microscope into fluorescence microscope (FM) with minimal interventions. SeeTB, a total internal reflection-based fluorescence excitation system allows visualization of auramine-O stained bacilli efficiently with high signal-to-noise ratio. Along with the device, we have developed a sputum-processing reagent called ‘CLR’ that homogenizes and digests the viscous polymer matrix of sputum. We have compared the performance of SeeTB system in 237 clinical sputum samples along with FM, GeneXpert and liquid culture. In comparison with culture as gold standard, FM has sensitivity of 63.77% and SeeTB has improved sensitivity to 76.06%. In comparison with GeneXpert, FM has sensitivity of 73.91% while SeeTB has improved sensitivity to 85.51%. However, there is no significant change in the specificity between FM and SeeTB system. In short, SeeTB system offers the most realistic option for improved TB case identification in resource-limited settings.

Dilatancy-based impression and fabrication technique for custom foot orthoses

2015 ◽  
Vol 40 (3) ◽  
pp. 409-413 ◽  
Author(s):  
Larissa A Sletto ◽  
Yeongchi Wu ◽  
Christopher Robinson
Keyword(s):  
Developed Countries ◽  
Clinic Visit ◽  
Technical Note ◽  
Foot Orthoses ◽  
Fabrication Technique ◽  
Resource Limited ◽  
Short Period ◽  
Set Up ◽  
Plaster Bandage ◽  
Foot Orthosis

Background and aim: Current methods used to take impressions for custom foot orthoses include plaster bandage, foam box, fiberglass, and laser-optical scanner. Impressions are converted to positive plaster or foam models. These methods create waste and may not be feasible in resource-limited areas. This technical note presents an alternative, greener impression and fabrication technique for foot orthoses that utilizes the dilatancy principle. Technique: Steps of the dilatancy (vacuum-based) procedure include taking an impression of the foot, converting the negative mold to a positive sand model, modifying the positive sand model, and thermoforming the foot orthosis. Discussion: This plaster-less system is inexpensive to set up and maintain, is reusable thereby minimizing cost and waste, and is clean to use. It enables a practitioner to quickly take an impression for fabricating a foot orthosis in a short period of time during a single clinic visit by the patient. Clinical relevance The dilatancy casting system could potentially be a cheaper, faster, and greener alternative procedure for fabricating custom foot orthoses in both developing and developed countries.

scholarly journals Gasless laparoscopy versus conventional laparoscopy and laparotomy. A systematic review on the safety and efficiency

2021 ◽  
Author(s):  
Haitham Shoman ◽  
Simone Sandler ◽  
Alexander Peters ◽  
Ameer Farooq ◽  
Magdalen Gruendl ◽  
...  
Keyword(s):  
Assessment Tool ◽  
A Priori ◽  
Conventional Laparoscopy ◽  
Viable Option ◽  
Gasless Laparoscopy ◽  
Resource Limited ◽  
Duration Of Surgery ◽  
The Mean ◽  
Set Up

Abstract Background Gasless laparoscopy emerged to overcome the clinical and financial challenges of pneumoperitoneum and is often seen as a viable option for use in resource-limited settings as a means of saving costs and resources. This study aims to systematically review the evidence available on the safety and efficiency of gasless laparoscopy compared to conventional laparoscopy and laparotomy.Methods Following PRISMA guidelines, Medline, Embase, Web of Science and Cochrane were searched. Variables of interest were determined a priori and Covidence software was used to screen studies for inclusion without demographic preference. The quality of studies was assessed using the Cochrane Risk Assessment tool.Results Of 1080 screened studies a total of 43 studies were included. Laparoscopic cholecystectomy was by far the most studied intervention in randomized studies. In these, the mean set-up time for gasless and conventional laparoscopy was 13.14 (95% CI: -0.16–26.44) and 12.8 (95% CI: -10.86–36.47) minutes respectively; The mean duration of surgery for gasless and conventional laparoscopy was 89.39 (95% CI: 77.44-101.34) and 72.59 (95% CI: 63.44–81.74) minutes respectively and the mean length of stay was 4.25 (95% CI: 2.02–6.48) and 4.04 (95% CI: 1.72–6.36) days respectively. Most reported complications were hemorrhage and infection with no assessable statistical difference.Conclusions Although gasless laparoscopy seems to be a feasible approach for many general surgery interventions, the observed outcomes based on safety and efficiency don’t suffice to recommend gasless laparoscopy as an alternative to conventional laparoscopy or laparotomy. Larger randomized trials with a low risk of bias are warranted.

scholarly journals IV DripAssist: An Innovative Way to Monitor Intravenous Infusions Away From an Outlet?

2019 ◽  
Vol 184 (Supplement_1) ◽  
pp. 322-325
Author(s):  
Kyle Couperus ◽  
Karl Kmiecik ◽  
Christopher Kang
Keyword(s):  
Medical Center ◽  
Physician Assistants ◽  
Ease Of Use ◽  
Patient Treatment ◽  
Perceived Ease Of Use ◽  
Need For Power ◽  
Resource Limited ◽  
Manual Counting ◽  
Actual Field ◽  
Set Up

Abstract Intravenous (IV) administration of fluids and medications are a significant part of patient treatment. In austere environments, typical methods of counting drops from gravity drips or infusion pumps both have limitations such as accuracy, weight, and need for power. The DripAssist device calculates drip rates by counting drops in IV tubing drip chambers and may provide a useful patient safety monitor adjunct. The protocol was IRB approved, prospective, and designed as a pilot study involving 28 Madigan Army Medical Center Emergency Department personnel. After a brief didactic introduction to the device for clinical staff with no prior experience using the device, participants were timed setting three normal saline infusions at rates of 250 mL/h, 125 mL/h and 83 mL/h with 15gtt/mL tubing. Participants filled out a survey on perceived ease of use and utility of the device compared to pumps and manual counting. Most participants felt the DripAssist device was easy to understand and set up, but nurses and physician assistants were more likely than medics to perceive a benefit versus IV pumps or gravity drips. The DripAssist device may offer a safe, low-weight, functional tool which could improve care in a variety of resource-limited environments. However, additional studies using the device during actual field exercises would be beneficial.

scholarly journals Molecular Dynamics Simulations of Wild Type and Mutants of SAPAP in Complexed with Shank3

2019 ◽  
Vol 20 (1) ◽  
pp. 224 ◽  
Author(s):  
Lianhua Piao ◽  
Zhou Chen ◽  
Qiuye Li ◽  
Ranran Liu ◽  
Wei Song ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Specific Binding ◽  
Neurological Diseases ◽  
Pdz Domain ◽  
Dynamics Simulation ◽  
Binding Motif ◽  
Wild Type ◽  
Set Up ◽  
Dynamics Simulations ◽  
High Flexibility

Specific interactions between scaffold protein SH3 and multiple ankyrin repeat domains protein 3 (Shank3) and synapse-associated protein 90/postsynaptic density-95–associated protein (SAPAP) are essential for excitatory synapse development and plasticity. In a bunch of human neurological diseases, mutations on Shank3 or SAPAP are detected. To investigate the dynamical and thermodynamic properties of the specific binding between the N-terminal extended PDZ (Post-synaptic density-95/Discs large/Zonaoccludens-1) domain (N-PDZ) of Shank3 and the extended PDZ binding motif (E-PBM) of SAPAP, molecular dynamics simulation approaches were used to study the complex of N-PDZ with wild type and mutated E-PBM peptides. To compare with the experimental data, 974QTRL977 and 966IEIYI970 of E-PBM peptide were mutated to prolines to obtain the M4P and M5P system, respectively. Conformational analysis shows that the canonical PDZ domain is stable while the βN extension presents high flexibility in all systems, especially for M5P. The high flexibility of βN extension seems to set up a barrier for the non-specific binding in this area and provide the basis for specific molecular recognition between Shank3 and SAPAP. The wild type E-PBM tightly binds to N-PDZ during the simulation while loss of binding is observed in different segments of the mutated E-PBM peptides. Energy decomposition and hydrogen bonds analysis show that M4P mutations only disrupt the interactions with canonical PDZ domain, but the interactions with βN1′ remain. In M5P system, although the interactions with βN1′ are abolished, the binding between peptide and the canonical PDZ domain is not affected. The results indicate that the interactions in the two-binding site, the canonical PDZ domain and the βN1′ extension, contribute to the binding between E-PBM and N-PDZ independently. The binding free energies calculated by MM/GBSA (Molecular Mechanics/Generalized Born Surface Area) are in agreement with the experimental binding affinities. Most of the residues on E-PBM contribute considerably favorable energies to the binding except A963 and D964 in the N-terminal. The study provides information to understand the molecular basis of specific binding between Shank3 and SAPAP, as well as clues for design of peptide inhibitors.

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