Precise sample metering method by coordinated burst action of hydrophobic burst valves applied to dried blood spot collection

Lab on Chip, 2021,21, 4445-4454

Student ID: 110033612

Name : 李佩容

Outline

03

02

04

01

INTRODUCTION

Discussion

Materials

&

METHODS

Conclusion

Introduction

Introduction

• Unknown blood volumes present in the samples may influence traditional protocols analysis data.

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• Dried blood spot sampling acts as an alternative sample collection method.

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• Precisely metered volumes from a blood drop and load them on pre-cut filter paper.

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Dried Blood Spot(DBS)

• DBS sampling of capillary blood is a promising invasive alternative to conventional venipuncture.

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• DBS sampling could be used in a multitude of areas like therapeutic drug monitoring, pharmacokinetics, and diagnosis of infectious diseases.

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• These applications take advantage of improved logistical convenience, reduced cost, automatable processing, and increased analyte stability.

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Hematocrit (Hct)

• High variability in blood sample among different groups of patients induces biases in quantitative bioanalyses.

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• As blood with different Hct levels spreads differently through filter paper as a direct consequence of its different viscosity, DBS sub-punches with the same area contain different blood volumes linked to the respective Hct levels.

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• Since red blood cells tend to accumulate at the edges of the DBS, applying larger blood volumes in the central versus peripheral area of the DBS will lead to different assay data.

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Materials�&�Methods

Hydrophobic Burst Valve fabrication

Incubation

Mask-coated strategy

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Hydrophobic Burst Valve fabrication

• The Aquapel and Fluoropel coated substrates were integrated in a microfluidic channel as bottom to create a sc HBV or as bottom and top for the dc HBV.

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HBV-1

HBV-2

Sample metering system characterization

Preload(20 µL)

• The volumetric performance of the microfluidic metering system was assessed by a gravimetric method.

Experimental setup

Waste channel

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Syringe pump

Excessive sample

Results�&�Discussion

HBV characterization(contact angle)

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Sample metering system(work flow)

T-junction

HBV-1

HBV-2

Burst

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HBV-2

Filling

Sample metering system

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Sample metering system

(gravimetric measurements)

• Good reproducibility

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• High accuracy

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• The loss is proportional to the length of the channels.

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3% deviation

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Conclusion

Conclusion

• In this work, a passive, low-cost and user-friendly microfluidic DBS sampling device is presented, utilizing coordinated burst actions of hydrophobic burst valves (HBVs) with configurable burst pressures.

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• The influence of two fluorinated solutions coated on specific channel regions on the contact angle and burst pressure is assessed.

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• The HBVs enable metering of predefined blood volumes starting from an unknown sample volume, ideal for multiplexed analyses on the same sample.

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Reference

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• “Precise sample metering method by coordinated burst action of hydrophobic burst valves applied to dried blood spot collection”, Dries Vloemans, Lorenz Van Hileghem, Wannes Verbist, a Debby Thomas, b Francesco Dal Dossoa and Jeroen Lammertyn, Lab on Chip, 2021,21, 4445-4454

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• “Low-cost rapid prototyping of flexible microfluidic devices using a desktop digital craft cutter”, Po Ki Yuen  and Vasiliy N. Goral, Lab Chip, 2010, 10, 384-387

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