Browsing by Author "Wang, Gang"

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    Shape Memory Alloy-based Whole Blood Glucose Monitoring Device: The e-Mosquito
    (2017) Wang, Gang; Mintchev, Martin; Yadid-Pecht, Orly; Smith, Michael; Yanushkevich, Svetlana; Murari, Kartikeya; Gavrilova, Marina; Kaminska, Bozena
    Diabetes Mellitus (DM) is a systemic disorder that results in elevated blood glucose levels in the body, leading to many secondary complications. Presently, manual fingerpicking tests remain the most popular method of blood glucose monitoring (BGM). However, the tests are often ignored by DM patients due to the pain and inconvenience. This thesis aims at addressing a growing demand for replacing the fingerpricking tests by presenting a wearable microsystem for minimally invasive, autonomous and pseudo-continuous blood glucose monitoring, the e-Mosquito. The proposed design of the e-Mosquito device aims to extract whole blood sample from a small lanced skin wound using a novel shape memory alloy (SMA)-based microactuator and directly measure the blood glucose level from this sample. A completely functional prototype of the e-Mosquito was developed. The prototype was first tested in-vitro on a custom-designed mechanical test station. Measurements showed that the output force and depth met the minimum requirements for reaching subcutaneous blood capillaries. The microactuation mechanism was also evaluated by extracting blood samples from the wrist of four human volunteers. 19 out of 23 actuations successfully reached capillary vessels below the wrist producing blood droplets on the surface of the skin. The integrated potentiostat-based glucose sensing circuit of the e-Mosquito device also showed a good linear correlation (R^2=0.9733) with measurements using standard BGM technology. These proof-of-concept studies demonstrated the feasibility of the SMA-based e-Mosquito device for replacing the fingerpricking tests in DM management.
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    Transcutaneous Intraluminal Impedance Measurement for Minimally Invasive Monitoring of Gastric Motility: Validation in Acute Canine Models
    (2014-12-09) Poscente, Michael D.; Wang, Gang; Filip, Dobromir; Ninova, Polya; Muench, Gregory; Yadid-Pecht, Orly; Mintchev, Martin P.; Andrews, Christopher N.
    Transcutaneous intraluminal impedance measurement (TIIM) is a new method to cutaneously measure gastric contractions by assessing the attenuation dynamics of a small oscillating voltage emitted by a battery-powered ingestible capsule retained in the stomach. In the present study, we investigated whether TIIM can reliably assess gastric motility in acute canine models. Methods. Eight mongrel dogs were randomly divided into 2 groups: half received an active TIIM pill and half received an identically sized sham capsule. After 24-hour fasting and transoral administration of the pill (active or sham), two force transducers (FT) were sutured onto the antral serosa at laparotomy. After closure, three standard cutaneous electrodes were placed on the abdomen, registering the transluminally emitted voltage. Thirty-minute baseline recordings were followed by pharmacological induction of gastric contractions using neostigmine IV and another 30-minute recording. Normalized one-minute baseline and post-neostigmine gastric motility indices (GMIs) were calculated and Pearson correlation coefficients (PCCs) between cutaneous and FT GMIs were obtained. Statistically significant GMI PCCs were seen in both baseline and post-neostigmine states. There were no significant GMI PCCs in the sham capsule test. Further chronic animal studies of this novel long-term gastric motility measurement technique are needed before testing it on humans.