179. real time ultrasound-based measurements of clotting time and implantable sensor for therapeutic drug monitoring of heparin

Department: NanoEngineering
Faculty Advisor(s): Jesse V. Jokerst

Primary Student
Name: Junxin Wang
Email: juw089@ucsd.edu
Phone: 858-534-6765
Grad Year: 2019

Abstract
Heparin anticoagulation therapy is an indispensable feature of clinical care yet has a narrow therapeutic window and is the second most common intensive care unit (ICU) medication error. The active partial thromboplastin time (aPTT) monitors heparin but suffers from long turnaround times, a variable reference range, limited utility with low molecular weight heparin, and poor correlation to dose. Here, we describe a photoacoustic imaging technique to monitor heparin concentration using methylene blue as a simple and Federal Drug Administration-approved contrast agent. We found a strong correlation between heparin concentration and photoacoustic signal measured in phosphate buffered saline (PBS) and blood. Clinically relevant heparin concentrations were detected in blood in 32 s with a detection limit of 0.28 U/mL. We validated this imaging approach by correlation to the aPTT (Pearson?s r = 0.86; p < 0.05) as well as with protamine sulfate treatment. This technique also has good utility with low molecular weight heparin (enoxaparin) including a blood detection limit of 72 &#956;g/mL. We then used these findings to create a nanoparticle-based hybrid material that can immobilize methylene blue for potential applications as a wearable/implantable heparin sensor to maintain drug levels in the therapeutic window. To the best of our knowledge, this is the first use of photoacoustics to image anticoagulation therapy with significant potential implications to the cardiovascular and surgical community.

Industry Application Area(s)
Life Sciences/Medical Devices & Instruments | Materials

Related Links:

  1. http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.6b02557

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