A New Optical Sweat Test Method Based on a Citric Acid-derived Multi-halide Sensor

Study Overview
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Brief Summary
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Cystic Fibrosis (CF) is a hereditary multi-system disease affecting approximately 30,000n children and adults in the USA. The diagnosis of CF requires biochemical confirmation (either abnormal sweat chloride measurement and/or identification of two CF disease causing mutations) plus clinical symptomatology. Measurements of sweat chloride remain cumbersome and although most common methodology to confirm CF diagnosis with limitations especially in young children less than 6 months of age and in areas that lack ability for the complex testing. The study objectives of this current research proposal include: A) To expand upon previously obtained pilot study data Evaluation of a fluorescent-based chloride sensor as an optical sweat test to diagnose cystic fibrosis B) To add the exploratory measurement of sweat Bromide as a first in human assessment observation, C) To Evaluate the development of smartphone based point-of-care technology for chloride and bromide sensor measurements, D) To further expand the class of citrate-based sensors with improved fluorescence and sensing properties for the design of new fluorescence-based analytical and diagnostic solutions based on the automated multi-halide detection system, and E) To develop point-of-care systems that can successfully integrate into clinical settings to improve current practices and facilitate early detection of disease.

Official Title
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A New Optical Sweat Test Method Based on a Citric Acid-derived Multi-halide Sensor

Conditions
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Cystic Fibrosis

Intervention / Treatment
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* Diagnostic Test: Measurement of Sweat Chloride and Sweat Bromide


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults 18 years of age or older capable of providing written informed consent AND Patients with an established diagnosis of Cystic Fibrosis (CF) OR Healthy volunteers Exclusion Criteria: Participants under medications or with disorders known to cause a positive error in the sweat test will be excluded in the study. Common causes of positive error in sweat test are mineralocorticoid hormone therapy, adrenal insufficiency, glycogen storage diseases, hypothyroidism, hypoparathyroidism, nephrogenic diabetes insipidus, G6PD deficiency or ectodermal dysplasia OR Any other skin or soft tissue disorders that could affect obtaining the necessary volumes of sweat.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Subjects with Cystic Fibrosis<br>Diagnostic | Diagnostic Test: Measurement of Sweat Chloride and Sweat Bromide<br>* Sweat Chloride comparisons between ion exchange chromatography and fluorescence citrate-based sensors<br>|
| Other: Healthy Volunteers<br>Diagnostic | Diagnostic Test: Measurement of Sweat Chloride and Sweat Bromide<br>* Sweat Chloride comparisons between ion exchange chromatography and fluorescence citrate-based sensors<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sweat chloride measurements in sweat samples via ion exchange chromatography | Sweat specimen samples obtained via pilocarpine iontophoresis will be measured for sweat chloride. Measurements for chloride will be determined by ion exchange chromatography measured in millimolar (mM). | anticipated 12 months | 
| Sweat chloride measurements in sweat samples via fluorescence quenching | Sweat specimen samples obtained via pilocarpine iontophoresis will be measured for sweat chloride. Measurements for the chloride will be determined by fluorescence citrate-based sensors, measured in millimolar (mM). | anticipated 12 months | 
| Sweat bromide measurements in sweat samples via fluorescence quenching | Sweat specimen samples obtained via pilocarpine iontophoresis will be measured for sweat bromide. Measurements for bromide will be determined by fluorescence citrate-based sensors, measured in millimolar (mM). | anticipated 12 months |