3D Printed Skin-Wash Sampler for Sweat Sampling in Cystic Fibrosis Diagnosis Using Capillary Electrophoretic Ion Ratio Analysis

Miriam Malá,Petra Itterheimová,Jana Vinohradská,Petr Kubáň,Lukáš Homola

doi:10.3390/separations8120234

Abstract

Sweat chloride analysis is one of the important approaches in cystic fibrosis diagnosis. The commonly used Macroduct method to acquire sweat samples is semi-invasive, time consuming and expensive. Furthermore, this method often fails to collect a sufficient amount of sweat in newborns due to the insufficient sweating rate. In this work, we present a novel, simple, 3D-printed sampling device that is used to collect sweat specimens completely noninvasively in less than one minute. The device has a flow-through channel adjacent to the skin surface, through which 500 µL of deionized water is flushed and the spontaneously formed sweat on the skin in the channel area is washed into a plastic vial. The developed skin-wash procedure is a single step operation, is completely noninvasive and it always produces a sweat specimen. The ions from the skin-wash are subsequently analyzed by capillary electrophoresis with contactless conductivity detection and selected ion ratio (Cl−/K+) or ((Cl− + Na+)/K+) is used as a cut-off value to diagnose cystic fibrosis patients with sensitivity and specificity comparable to the conventional Macroduct method.

Highlights

IntroductionSweat is an important diagnostic sample in cystic fibrosis (CF), a rare incurable autosomal recessive inherited disease [1]
Introduction published maps and institutional affilSweat is an important diagnostic sample in cystic fibrosis (CF), a rare incurable autosomal recessive inherited disease [1]
The same system and background electrolyte (BGE) were used for analysis of anions and cations, except that the polarity of the high-voltage power supply was switched from positive to negative

Summary

Introduction

Sweat is an important diagnostic sample in cystic fibrosis (CF), a rare incurable autosomal recessive inherited disease [1]. The mutation in cystic fibrosis transmembrane conductance regulator (CFTR) gene results in defective ion transfer through epithelial cellular membranes in CF patients and the unambiguous diagnostic tool is to measure the chloride concentration in sweat. The value above 60 mmol/L [2] is used as a cut-off to confirm the diagnosis of CF diagnosis in newborn screening programs across the world [3]. A clearly negative result of the sweat test is a value below 30 mmol/L, and the gray zone of the range between these values should be interpreted in connection with the clinical condition of the patient and possibly after the completion of other tests, including genetic testing.

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Results

Conclusion