scholarly journals A plasmonic gold nanofilm-based microfluidic chip for rapid and inexpensive droplet-based photonic PCR

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abbas Jalili ◽  
Maryam Bagheri ◽  
Amir Shamloo ◽  
Amir Hossein Kazemipour Ashkezari
Keyword(s):  
Microfluidic Chip ◽  
Point Of Care ◽  
Pcr Amplification ◽  
Alcohol Oxidase ◽  
Nucleic Acid Amplification ◽  
Adhesive Tape ◽  
Microfluidic Chips ◽  
Fast Heating ◽  
Light Emitting ◽  
Heating And Cooling

AbstractPolymerase chain reaction (PCR) is a powerful tool for nucleic acid amplification and quantification. However, long thermocycling time is a major limitation of the commercial PCR devices in the point-of-care (POC). Herein, we have developed a rapid droplet-based photonic PCR (dpPCR) system, including a gold (Au) nanofilm-based microfluidic chip and a plasmonic photothermal cycler. The chip is fabricated by adding mineral oil to uncured polydimethylsiloxane (PDMS) to suppress droplet evaporation in PDMS microfluidic chips during PCR thermocycling. A PDMS to gold bonding technique using a double-sided adhesive tape is applied to enhance the bonding strength between the oil-added PDMS and the gold nanofilm. Moreover, the gold nanofilm excited by two light-emitting diodes (LEDs) from the top and bottom sides of the chip provides fast heating of the PCR sample to 230 °C within 100 s. Such a design enables 30 thermal cycles from 60 to 95 °C within 13 min with the average heating and cooling rates of 7.37 ± 0.27 °C/s and 1.91 ± 0.03 °C/s, respectively. The experimental results demonstrate successful PCR amplification of the alcohol oxidase (AOX) gene using the rapid plasmonic photothermal cycler and exhibit the great performance of the microfluidic chip for droplet-based PCR.

An on-chip valve-assisted microfluidic chip for quantitative and multiplexed detection of biomarkers

2018 ◽  
Vol 10 (21) ◽  
pp. 2470-2480 ◽  
Author(s):  
Binfeng Hu ◽  
Yong Liu ◽  
Jinqi Deng ◽  
Lei Mou ◽  
Xingyu Jiang
Keyword(s):  
Microfluidic Chip ◽  
Point Of Care ◽  
Microfluidic Chips ◽  
Portable Instrument ◽  
Multiplexed Detection ◽  
On Chip ◽  
Detection Of Biomarkers

A point-of-care immunoassay platform including on-chip valve-assisted microfluidic chips and a portable instrument for quantitative and multiplexed detection of biomarkers.

scholarly journals Integrated, Automated, Fast PCR System for Point-Of-Care Molecular Diagnosis of Bacterial Infection

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 377
Author(s):  
Dongkyu Lee ◽  
Deawook Kim ◽  
Jounghyuk Han ◽  
Jongsu Yun ◽  
Kang-Ho Lee ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Fluorescence Intensity ◽  
Pathogenic Bacteria ◽  
Point Of Care ◽  
Pcr Amplification ◽  
Sample Volume ◽  
Separation And Purification ◽  
Heating And Cooling ◽  
Automated Sample Preparation ◽  
Commercial Device

We developed an integrated PCR system that performs automated sample preparation and fast polymerase chain reaction (PCR) for application in point-of care (POC) testing. This system is assembled from inexpensive 3D-printing parts, off-the-shelf electronics and motors. Molecular detection requires a series of procedures including sample preparation, amplification, and fluorescence intensity analysis. The system can perform automated DNA sample preparation (extraction, separation and purification) in ≤5 min. The variance of the automated sample preparation was clearly lower than that achieved using manual DNA extraction. Fast thermal ramp cycles were generated by a customized thermocycler designed to automatically transport samples between heating and cooling blocks. Despite the large sample volume (50 μL), rapid two-step PCR amplification completed 40 cycles in ≤13.8 min. Variations in fluorescence intensity were measured by analyzing fluorescence images. As proof of concept of this system, we demonstrated the rapid DNA detection of pathogenic bacteria. We also compared the sensitivity of this system with that of a commercial device during the automated extraction and fast PCR of Salmonella bacteria.

scholarly journals Pulse-Controlled Amplification – a new powerful tool for front-line diagnostics

2020 ◽  
Author(s):  
Katharina Müller ◽  
Sarah Daßen ◽  
Scott Holowachuk ◽  
Katrin Zwirglmaier ◽  
Joachim Stehr ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Molecular Diagnostics ◽  
Standard Technique ◽  
Rapid Identification ◽  
Nucleic Acid Amplification ◽  
Target Sequence ◽  
Infectious Agents ◽  
Fast Heating ◽  
Heating And Cooling ◽  
Nucleic Acid Amplification Technology

ABSTRACTMolecular diagnostics has become essential in the identification of many infectious diseases, and the detection of nucleic acids often serves as the gold standard technique for most infectious agents. However, established techniques like polymerase chain reaction (PCR) are time-consuming laboratory-bound techniques. Here we present an alternative method for the rapid identification of infectious agents using pulse-controlled amplification (PCA). PCA is a next generation nucleic acid amplification technology that uses rapid energy pulses to heat microcyclers (micro-scale metal heating elements embedded directly in the amplification reaction) for a few microseconds, thus only heating a small fraction of the reaction volume. The heated microcyclers cool off nearly instantaneously, resulting in ultra-fast heating and cooling cycles during which classic amplification of a target sequence takes place. This reduces the overall amplification time by a factor of up to 10, enabling a sample-to-result workflow in just 15 minutes, while running on a small and portable prototype device. We could demonstrate the efficacy of this technology in two assays, one for a nosocomial context targeting MecA conferred antibiotic resistance, and one for a biothreat scenario targeting Yersinia pestis. The observed limits of detection were 10 copies per reaction (purified DNA) for MecA in a methicillin resistant Staphylococcus aureus and 434 copies per reaction (purified DNA) or 9.8 cells per reaction (crude sample) of Yersinia pestis. Thus, PCA offers a decentralization of molecular diagnostics and is applicable whenever rapid, on-site detection of infectious agents is needed.

scholarly journals A fast and simple bonding method for low cost microfluidic chip fabrication

2018 ◽  
Vol 69 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Zhifu Yin ◽  
Helin Zou
Keyword(s):  
Microfluidic Chip ◽  
Low Cost ◽  
Adhesive Tape ◽  
Microfluidic Chips ◽  
Bonding Pressure ◽  
Gas Leakage ◽  
Microstructure Fabrication ◽  
Chip Fabrication ◽  
Commercial Applications ◽  
Bonding Method

Abstract With the development of the microstructure fabrication technique, microfluidic chips are widely used in biological and medical researchers. Future advances in their commercial applications depend on the mass bonding of microfluidic chip. In this study we are presenting a simple, low cost and fast way of bonding microfluidic chips at room temperature. The influence of the bonding pressure on the deformation of the microchannel and adhesive tape was analyzed by numerical simulation. By this method, the microfluidic chip can be fully sealed at low temperature and pressure without using any equipment. The dye water and gas leakage test indicated that the microfluidic chip can be bonded without leakage or block and its bonding strength can up to 0.84 MPa.

Texture Evolution Under Fast Heating and Cooling Rates of Zirconium Alloys Studied In-Situ by Synchrotron X-Ray Diffraction

2020 ◽  
Author(s):  
Chi-Toan Nguyen ◽  
Alistair Garner ◽  
Javier Romero ◽  
Antoine Ambard ◽  
Michael Preuss ◽  
...  
Keyword(s):  
Texture Evolution ◽  
Zirconium Alloys ◽  
X Ray Diffraction ◽  
Fast Heating ◽  
Cooling Rates ◽  
X Ray ◽  
Heating And Cooling

scholarly journals Laboratory-Scale Processing and Performance Assessment of Ti–Ta High-Temperature Shape Memory Spring Actuators

2021 ◽  
Author(s):  
A. Paulsen ◽  
H. Dumlu ◽  
D. Piorunek ◽  
D. Langenkämper ◽  
J. Frenzel ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory ◽  
Detrimental Effect ◽  
Wire Drawing ◽  
Fast Heating ◽  
Heating And Cooling ◽  
Arc Melting ◽  
Ω Phase ◽  
And Performance

AbstractTi75Ta25 high-temperature shape memory alloys exhibit a number of features which make it difficult to use them as spring actuators. These include the high melting point of Ta (close to 3000 °C), the affinity of Ti to oxygen which leads to the formation of brittle α-case layers and the tendency to precipitate the ω-phase, which suppresses the martensitic transformation. The present work represents a case study which shows how one can overcome these issues and manufacture high quality Ti75Ta25 tensile spring actuators. The work focusses on processing (arc melting, arc welding, wire drawing, surface treatments and actuator spring geometry setting) and on cyclic actuator testing. It is shown how one can minimize the detrimental effect of ω-phase formation and ensure stable high-temperature actuation by fast heating and cooling and by intermediate rejuvenation anneals. The results are discussed on the basis of fundamental Ti–Ta metallurgy and in the light of Ni–Ti spring actuator performance.

scholarly journals Design and experimental investigation of a novel spiral microfluidic chip to separate wide size range of micro-particles aimed at cell separation

2021 ◽  
pp. 095441192110297
Author(s):  
Seyed Ali Tabatabaei ◽  
Mohammad Zabetian Targhi
Keyword(s):  
Point Of Care ◽  
Diagnostic System ◽  
Average Diameter ◽  
Microfluidic System ◽  
Microfluidic Chips ◽  
Medical Sciences ◽  
Blood Samples ◽  
Micro Particles ◽  
Monodisperse Polystyrene ◽  
Device Size

Isolation of microparticles and biological cells on microfluidic chips has received considerable attention due to their applications in numerous areas such as medical and engineering fields. Microparticles separation is of great importance in bioassays due to the need for smaller sample and device size and lower manufacturing costs. In this study, we first explain the concepts of separation and microfluidic science along with their applications in the medical sciences, and then, a conceptual design of a novel inertial microfluidic system is proposed and analyzed. The PDMS spiral microfluidic device was fabricated, and its effects on the separation of particles with sizes similar to biological particles were experimentally analyzed. This separation technique can be used to separate cancer cells from the normal ones in the blood samples. These components required for testing were selected, assembled, and finally, a very affordable microfluidic kit was provided. Different experiments were designed, and the results were analyzed using appropriate software and methods. Separator system tests with polydisperse hollow glass particles (diameter 2–20 µm), and monodisperse Polystyrene particles (diameter 5 & 15 µm), and the results exhibit an acceptable chip performance with 86% of efficiency for both monodisperse particles and polydisperse particles. The microchannel collects particles with an average diameter of 15.8, 9.4, and 5.9 μm at the proposed reservoirs. This chip can be integrated into a more extensive point-of-care diagnostic system to test blood samples.

scholarly journals Microfluidics-Based Plasmonic Biosensing System Based on Patterned Plasmonic Nanostructure Arrays

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 826
Author(s):  
Yanting Liu ◽  
Xuming Zhang
Keyword(s):  
Plasmon Resonance ◽  
Point Of Care ◽  
Simultaneous Detection ◽  
High Sensitivity ◽  
Microfluidic Chips ◽  
Label Free ◽  
Plasmonic Nanostructure ◽  
Point Of Care Diagnostics ◽  
Surface Enhanced Raman ◽  
Nanostructure Arrays

This review aims to summarize the recent advances and progress of plasmonic biosensors based on patterned plasmonic nanostructure arrays that are integrated with microfluidic chips for various biomedical detection applications. The plasmonic biosensors have made rapid progress in miniaturization sensors with greatly enhanced performance through the continuous advances in plasmon resonance techniques such as surface plasmon resonance (SPR) and localized SPR (LSPR)-based refractive index sensing, SPR imaging (SPRi), and surface-enhanced Raman scattering (SERS). Meanwhile, microfluidic integration promotes multiplexing opportunities for the plasmonic biosensors in the simultaneous detection of multiple analytes. Particularly, different types of microfluidic-integrated plasmonic biosensor systems based on versatile patterned plasmonic nanostructured arrays were reviewed comprehensively, including their methods and relevant typical works. The microfluidics-based plasmonic biosensors provide a high-throughput platform for the biochemical molecular analysis with the advantages such as ultra-high sensitivity, label-free, and real time performance; thus, they continue to benefit the existing and emerging applications of biomedical studies, chemical analyses, and point-of-care diagnostics.

scholarly journals Diagnosis of Herpes Simplex Virus: Laboratory and Point-of-Care Techniques

2021 ◽  
Vol 13 (2) ◽  
pp. 518-539
Author(s):  
Peuli Nath ◽  
Md Alamgir Kabir ◽  
Somaiyeh Khoubafarin Doust ◽  
Aniruddha Ray
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Point Of Care ◽  
Diagnostic Techniques ◽  
Nucleic Acid Amplification ◽  
Physical Contact ◽  
Detection Sensitivity ◽  
Detection Techniques ◽  
Advantages And Disadvantages ◽  
Simplex Virus

Herpes is a widespread viral infection caused by the herpes simplex virus (HSV) that has no permanent cure to date. There are two subtypes, HSV-1 and HSV-2, that are known to cause a variety of symptoms, ranging from acute to chronic. HSV is highly contagious and can be transmitted via any type of physical contact. Additionally, viral shedding can also happen from asymptomatic infections. Thus, early and accurate detection of HSV is needed to prevent the transmission of this infection. Herpes can be diagnosed in two ways, by either detecting the presence of the virus in lesions or the antibodies in the blood. Different detection techniques are available based on both laboratory and point of care (POC) devices. Laboratory techniques include different biochemical assays, microscopy, and nucleic acid amplification. In contrast, POC techniques include microfluidics-based tests that enable on-spot testing. Here, we aim to review the different diagnostic techniques, both laboratory-based and POC, their limits of detection, sensitivity, and specificity, as well as their advantages and disadvantages.

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