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

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.

Download Full-text

Detector-Free Photothermal Bar-Chart Microfluidic Chips (PT-Chips) for Visual Quantitative Detection of Biomarkers

10.26434/chemrxiv.14131514 ◽

2021 ◽

Author(s):

Wan Zhou ◽

Guanglei Fu [email protected] ◽

Xiujun Li

Keyword(s):

Whole Blood ◽

Limit Of Detection ◽

Point Of Care ◽

Clinical Diagnostics ◽

Detection Sensitivity ◽

Quantitative Detection ◽

Microfluidic Chips ◽

Analytical Instruments ◽

Photothermal Effects ◽

On Chip

The volumetric bar-chart microfluidic chips (V-Chips) driven by chemical reaction-generated gas provide a promising platform for point-of-care (POC) visual biomarker quantitation. However, multiple limitations are encountered in conventional V-Chips, such as costly and complex chip fabrication, complicated assembly, and imprecise controllability of gas production. Herein, we introduced nanomaterial-mediated photothermal effects to V-Chips, and for the first time developed a new type of V-Chip, photothermal bar-chart microfluidic chip (PT-Chip), for visual quantitative detection of biochemicals without any bulky and costly analytical instruments. Immunosensing signals were converted to visual readout signals via photothermal effects, the on-chip bar-chart movements, enabling quantitative biomarker detection on a low-cost polymer hybrid PT-Chip with on-chip scale rulers. Four different human serum samples containing prostate-specific antigen (PSA) as a model analyte were detected simultaneously using the PT-Chip, with the limit of detection of 2.1 ng/mL, meeting clinical diagnostic requirements. Although no conventional signal detectors were used, it achieved comparable detection sensitivity to absorbance measurements with a microplate reader. The PT-Chip was further validated by testing human whole blood without the color interference problem, demonstrating good analytical performance of our method even in complex matrixes and thus the potential to fill a gap in current clinical diagnostics that is incapable of testing whole blood. This new PT-Chip driven by nanomaterial-mediated photothermal effects opens a new horizon of microfluidic platforms for instrument-free diagnostics at the point of care.

Download Full-text

Detector-Free Photothermal Bar-Chart Microfluidic Chips (PT-Chips) for Visual Quantitative Detection of Biomarkers

10.26434/chemrxiv.14131514.v1 ◽

2021 ◽

Author(s):

Wan Zhou ◽

Guanglei Fu [email protected] ◽

Xiujun Li

Keyword(s):

Whole Blood ◽

Limit Of Detection ◽

Point Of Care ◽

Clinical Diagnostics ◽

Detection Sensitivity ◽

Quantitative Detection ◽

Microfluidic Chips ◽

Analytical Instruments ◽

Photothermal Effects ◽

On Chip

The volumetric bar-chart microfluidic chips (V-Chips) driven by chemical reaction-generated gas provide a promising platform for point-of-care (POC) visual biomarker quantitation. However, multiple limitations are encountered in conventional V-Chips, such as costly and complex chip fabrication, complicated assembly, and imprecise controllability of gas production. Herein, we introduced nanomaterial-mediated photothermal effects to V-Chips, and for the first time developed a new type of V-Chip, photothermal bar-chart microfluidic chip (PT-Chip), for visual quantitative detection of biochemicals without any bulky and costly analytical instruments. Immunosensing signals were converted to visual readout signals via photothermal effects, the on-chip bar-chart movements, enabling quantitative biomarker detection on a low-cost polymer hybrid PT-Chip with on-chip scale rulers. Four different human serum samples containing prostate-specific antigen (PSA) as a model analyte were detected simultaneously using the PT-Chip, with the limit of detection of 2.1 ng/mL, meeting clinical diagnostic requirements. Although no conventional signal detectors were used, it achieved comparable detection sensitivity to absorbance measurements with a microplate reader. The PT-Chip was further validated by testing human whole blood without the color interference problem, demonstrating good analytical performance of our method even in complex matrixes and thus the potential to fill a gap in current clinical diagnostics that is incapable of testing whole blood. This new PT-Chip driven by nanomaterial-mediated photothermal effects opens a new horizon of microfluidic platforms for instrument-free diagnostics at the point of care.

Download Full-text

Integrated Microfluidic Flow Sensor for LAB-oN-CHIP and PoINT-oF-CARE Applications

Biotekhnologiya ◽

10.21519/0234-2758-2020-36-4-112-120 ◽

2020 ◽

Vol 36 (4) ◽

pp. 112-120

Author(s):

A.V. Zverev ◽

M. Andronik ◽

V.V. Echeistov ◽

Z.H. Issabayeva ◽

O.S. Sorokina ◽

...

Keyword(s):

Numerical Simulation ◽

Flow Rate ◽

Microfluidic Chip ◽

Soft Lithography ◽

Point Of Care ◽

Flow Sensor ◽

Oxide Semiconductor ◽

Dead Volume ◽

Lab On Chip ◽

On Chip

The results of the development and manufacture of an integrated membrane-free sensor for the control of accurate dilution of liquid samples on the microfluidic chip are presented. The proposed type of devices is intended for direct precise measurements of liquid flow rate in microchannels of laboratories-on-chip, including point-of-care systems. The sensor topology was optimized based on the numerical simulation results and technological requirements. The main characteristic of the developed sensor is the lack of a membrane in the design while maintaining the sensitivity and accuracy of the device at the level of a commercial membrane analogue. The fully biocompatible sensor was manufactured using standard microelectronics and soft lithography technologies. In order to optimize the sensor design, 32 different topologies of the device were tested. The integration of the flow sensors on the chip allows to significantly reduce the dead volume of the hydrodynamic system and to control the amount of liquid entering the individual reservoirs of the microfluidic chip. The sensor occupies an area of (210 x 140) um2 in the channel and is characterized by a relative error of 5% in the flow rate range of 100-1000 ul/min. microfluidics, lab-on-chip, calorimetric flow sensor, thermoresistive sensor, numerical simulation, hydrodynamics, complementary metal-oxide-semiconductor, microtechnologies Devices were made at the BMSTU Nanofabrication Facility (FMN Laboratory, FMNS REC, ID 74300).

Download Full-text

Smartphone-app based point-of-care testing for myocardial infarction biomarker cTnI using an autonomous capillary microfluidic chip with self-aligned on-chip focusing (SOF) lenses

Lab on a Chip ◽

10.1039/c9lc00259f ◽

2019 ◽

Vol 19 (10) ◽

pp. 1797-1807 ◽

Cited By ~ 8

Author(s):

Chao Liang ◽

Yuanchang Liu ◽

Aiying Niu ◽

Chong Liu ◽

Jingmin Li ◽

...

Keyword(s):

Myocardial Infarction ◽

Fluorescence Intensity ◽

Microfluidic Chip ◽

Point Of Care ◽

The Self ◽

Smartphone App ◽

Point Of Care Testing ◽

On Chip

We present a smartphone-app platform for point-of-care testing of cTnI, which features the self-aligned on-chip focusing (SOF) lenses for enhancing the fluorescence intensity.

Download Full-text

Ultrasensitive optofluidic enzyme-linked immunosorbent assay by on-chip integrated polymer whispering-gallery-mode microlaser sensors

Lab on a Chip ◽

10.1039/d0lc00240b ◽

2020 ◽

Vol 20 (14) ◽

pp. 2438-2446 ◽

Cited By ~ 1

Author(s):

Xia Ouyang ◽

Tong Liu ◽

Yangxi Zhang ◽

Jijun He ◽

Zijian He ◽

...

Keyword(s):

Immunosorbent Assay ◽

Microfluidic Chip ◽

Whispering Gallery Mode ◽

Enzyme Linked Immunosorbent Assay ◽

Ultrasensitive Detection ◽

Whispering Gallery ◽

On Chip ◽

Detection Of Biomarkers

Polymer whispering-gallery-mode microlaser sensors are optically 3D μ-printed and then integrated within a microfluidic chip for ultrasensitive detection of biomarkers.

Download Full-text

Microfluidic Immunoaffinity Basophil Activation Test for Point-of-Care Allergy Diagnosis

The Journal of Applied Laboratory Medicine ◽

10.1373/jalm.2018.026641 ◽

2019 ◽

Vol 4 (2) ◽

pp. 152-163 ◽

Cited By ~ 1

Author(s):

Zenib Aljadi ◽

Frida Kalm ◽

Harisha Ramachandraiah ◽

Anna Nopp ◽

Joachim Lundahl ◽

...

Keyword(s):

Flow Cytometry ◽

Microfluidic Device ◽

Microfluidic Chip ◽

Whole Blood ◽

Point Of Care ◽

Basophil Activation Test ◽

Healthy Controls ◽

Activation Test ◽

On Chip ◽

Cd63 Expression

Abstract Background The flow cytometry-based basophil activation test (BAT) is used for the diagnosis of allergic response. However, flow cytometry is time-consuming, requiring skilled personnel and cumbersome processing, which has limited its use in the clinic. Here, we introduce a novel microfluidic-based immunoaffinity BAT (miBAT) method. Methods The microfluidic device, coated with anti-CD203c, was designed to capture basophils directly from whole blood. The captured basophils are activated by anti-FcεRI antibody followed by optical detection of CD63 expression (degranulation marker). The device was first characterized using a basophil cell line followed by whole blood experiments. We evaluated the device with ex vivo stimulation of basophils in whole blood from healthy controls and patients with allergies and compared it with flow cytometry. Results The microfluidic device was capable of capturing basophils directly from whole blood followed by in vitro activation and quantification of CD63 expression. CD63 expression was significantly higher (P = 0.0002) in on-chip activated basophils compared with nonactivated cells. The difference in CD63 expression on anti-FcεRI-activated captured basophils in microfluidic chip was significantly higher (P = 0.03) in patients with allergies compared with healthy controls, and the results were comparable with flow cytometry analysis (P = 0.04). Furthermore, there was no significant difference of CD63% expression in anti-FcεRI-activated captured basophils in microfluidic chip compared with flow cytometry. Conclusions We report on the miBAT. This device is capable of isolating basophils directly from whole blood for on-chip activation and detection. The new miBAT method awaits validation in larger patient populations to assess performance in diagnosis and monitoring of patients with allergies at the point of care.

Download Full-text

INTEGRATED MICROFLUIDIC FLOW SENSOR FOR LAB-ON-CHIP AND POINT-OF-CARE APPLICATIONS

BIOTECHNOLOGY: STATE OF THE ART AND PERSPECTIVES ◽

10.37747/2312-640x-2020-18-457-458 ◽

2020 ◽

pp. 457-458

Author(s):

V. Ryzhkov ◽

M. Andronik ◽

V. Echeistov ◽

Z. Issabayeva ◽

O. Sorokina ◽

...

Keyword(s):

Microfluidic Chip ◽

Point Of Care ◽

Experimental Comparison ◽

Fluid Flow Rate ◽

Fabrication Technology ◽

Flow Sensors ◽

Lab On Chip ◽

Microfluidic Flow ◽

Chip Fabrication ◽

On Chip

An integrated membrane-free sensor for precise measurements of fluid flow rate in microchannels of laboratories-on- chip has been developed. The sensor allows to measure flow on microfluidic chip in real time and is designed for liquid samples precise dilution control on the microfluidic chip. Fabrication technology of the microfluidic chip with built-in flow sensors as well as results of experimental comparison of developed sensor with a commercial flowmeter are presented.

Download Full-text

Design and Fabrication of Multichannel PDMS Microfluidic

Journal of Physics Conference Series ◽

10.1088/1742-6596/2129/1/012048 ◽

2021 ◽

Vol 2129 (1) ◽

pp. 012048

Author(s):

M N Afnan Uda ◽

U Hashim ◽

M N A Uda ◽

N A Parmin ◽

V Thivina

Keyword(s):

Contact Area ◽

Microfluidic Chip ◽

Point Of Care ◽

Main Tool ◽

Morphological Properties ◽

Single Chip ◽

Lab On Chip ◽

Micro Channels ◽

On Chip ◽

Disease Analysis

Abstract Microfluidic delivers miniaturized fluidic networks for processing liquids in the microliter range. In the recent years, lab-on-chip (LOC) is become a main tool for point-of-care (POC) diagnostic especially in the medical field. In this paper, we presented a design and fabrication on multi disease analysis using single chip via delivery of fluid with the multiple transducers is the pathway of multi-channel microfluidic based LOC’s. 3 in 1 nano biosensor kit was attached with the microfluidic to produce nano-biolab-on-chip (NBLOC). The multi channels microfluidic chip was designed including the micro channels, one inlet, three outlet and sensor contact area. The microfluidic chip was designed to include multiplex detection for pathogen that consists of multiple channels of simultaneous results. The LOC system was designed using Design Spark Mechanical software and PDMS was used as a medium of the microfluidic. The microfluidic mold and PDMS microfluidic morphological properties have been characterized by using low power microscope (LPM), high power microscope (HPM) and surface profiler. The LOC system physical was experimental by dropping food coloring through the inlet and collecting at the sensor contact area outlet.

Download Full-text