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Photon-Based Point-of-Care Testing for Critical, Emergency, and Disaster Care

(Major Collaborator-Driven Research Project)

UC Davis: NK Tran, RF Louie, NL Gentile, GJ Kost; 

LLNL: B. Hindson, B Baker

In the past year, CBST researchers at UC Davis and Lawrence Livermore Laboratory (LLNL) received an $8.5M grant (U54EB007959) from the National Institute of Biomedical Imaging and Bioengineering (NIBIB) to establish and support the UC Davis-LLNL Point-of-Care (POC) Technologies Center. The Center is located at CBST in the Oak Park Research Building at the UC Davis Medical Center in Sacramento, CA. Point-of-Care testing (POCT) is defined as diagnostic testing at or near the site of patient care. Critical, emergency, and disaster care environments require accurate, robust, and novel diagnostic technologies to facilitate evidence-based treatment decisions by health care professionals. Types of POCT include transportable, portable, bench-top, and handheld devices. The current goal is to plan and execute the development of photon-based POCT devices that would be jointly supported by CBST and POC Technologies Center.

Candidate projects of photon-based POCT devices include:

1)    Development of a photon-based technology applied to endotracheal tubes to provide in vivo pathogen detection (see figure). This biosensor may assay the sputum for turbidity and fluorescence. Sepsis is the primary cause of death in non-coronary intensive care units (ICU). In surgical ICUs, ventilator associated pneumonias (VAP) account for 43% of all nosocomial infections. Given the high prevalence rate, mortality, and incidents of treatment failures, there is a need for in vivo monitoring for VAP.

2)    Hospital acquired wound infections occur 18% of the time in surgical intensive care patients. Post-surgical wounds, as well as existing wounds related to bacteria causing necrotizing fasciitis are at high risk for nosocomial infections and possibly sepsis. Previous work has shown that on a porous microcavity resonator-based biosensor, detection of red shifts occurred when presented with bacterial endotoxin. This technology may be enhanced with the use of flexible organic light emitting diode (OLED)-biosensors to monitor for wound infections. OLED’s are unique in their capacity to be printed onto any substrate.

P3)    Fluorescent microsphere-based cardiac biomarker testing in animal models has shown promise. Therefore, novel new approaches like real-time, percutaneous photometric assessment of myoglobin and bed-side myocardial perfusion imaging may reduce the mortality among misdiagnosed patients with acute coronary syndrome ACS. ACS is one of the leading causes of deaths in the emergency department.

Other candidate applications for photon-based critical care monitoring may include non-invasive blood glucose monitoring for tight glycemic control, transcutaneous monitoring of glomerular filtration rate, and biosensor integration with foley catheters and intravenous catheters for pathogen detection in urinary tract infections and bloodstream infections respectively. Integration of endotracheal, wound, urinary tract, and intravenous biosensors may reduce the need for pan culturing, and accelerate treatment decisions in the critical care setting.

The CPOCT is currently setting up laboratory its laboratory facilities at CBST and is in the process of planning its developmental activities. One project underway is the development of two prototype systems using loop-mediated isothermal amplification (LAMP) and photosensors for nucleic acid testing of high-risk pathogens including methicillin resistant Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Streptoccocus pneumoniae, and E. coli in whole blood samples. The prototype systems will be designed for use in community hospitals, rural settings, and at disaster response sites. One prototype will be ruggedized for field use by disaster medical assistance teams (DMATs).