Early imaging of tumor response to chemotherapy has the potential for significant clinical benefits. We are developing a
family of fiber-optic sensors called SencilsTM (sensory cilia), which are disposable, minimally invasive, and can provide
in vivo monitoring of various analytes for several weeks. The objective of this study was to develop and test our sensor to
image the labeling of phosphatidylserine by apoptotic cells in response to chemotherapeutic drugs. FM1-43 was a better
fluorescent marker for detecting phosphatidylserine expression than Annexin V-FITC; both the proportion of labeled
cells (Annexin V, 15%; FM1-43, 58%) and the relative fluorescent increase (Annexin V-FITC, 1.5-fold; FM1-43,
4.5-fold) was greater when FM1-43 was used to detect apoptosis. Initial testing of the optical sensing technology using
Taxol-treated MCF-7 cells demonstrated that injection of FM1-43 resulted in a rapid, transient increase in fluorescence
that was greater in apoptotic cells compared to control cells (apoptotic cells, 4-fold increase; control cells, 2-fold
increase). Using an established animal model, mice were injected with cyclophosphamide and hepatic apoptosis was
assessed by imaging of PS expression. Both the amplitude of fluorescence increase and the time taken for the amplitude
to decay to half of its peak were increased in livers from animals treated with cyclophosphamide. Our optical sensing
technology can be used to detect the early apoptotic response of cells to chemotherapeutic drugs both in vitro and in vivo.
This novel technology represents a unique option for the imaging of tumor responses in vivo, and provides an inexpensive, specific system for the detection of early-stage apoptosis.
KEYWORDS: Glucose, Sensors, Optical fibers, Luminescence, Polymers, Chemical analysis, In vivo imaging, Collagen, Ultraviolet radiation, Chemical fiber sensors
Sencilstm (sensory cilia) are chemical sensors that are minimally invasive, disposable and
easily readable to make frequent measurements of various analytes in vivo over a period of 1-3
months. A percutaneous optical fiber permits precise, reliable photonic measurement of chemical
reactions in a nano-engineered polymer matrix attached to the internal end of the fiber. The first
Sencils sense interstitial glucose based on measurement of fluorescence resonance energy transfer
(FRET) between fluorophores bound to betacyclodextrin and Concanavalin A (Con A) in a
polyethylene glycol (PEG) matrix. In vitro experiments demonstrate a rapid and precise relationship
between the ratio of the two fluorescent emissions and concentration of glucose in saline over the
physiological range of 0-500mg/dl. Chronic implantation in pigs has demonstrated biocompatibility.
The Sencil platform can be adapted to detect other analytes in interstitial fluids.
KEYWORDS: Glucose, Sensors, Luminescence, Fluorescence resonance energy transfer, Chemical analysis, Optical fibers, In vivo imaging, Polymers, Blood, Filtering (signal processing)
Sencils (sensory cilia) are chemical sensors that are minimally invasive, disposable and easily readable to make frequent measurements of various analytes in vivo over a period of 1-3 months. A percutaneous optical fiber permits precise, reliable photonic measurement of chemical reactions in a nano-engineered polymer matrix attached to the internal end of the fiber. The first Sencils sense interstitial glucose based on measurement of fluorescence resonance energy transfer (FRET) between fluorophors bound to dextran and Concanavalin-A in a polyethylene glycol (PEG) matrix. In vitro experiments demonstrate a rapid and precise relationship between the ratio of the two fluorescent emissions and concentration of glucose in saline over the physiological range of 0-500mg/dl. Chronic implantation in pigs has demonstrated biocompatibility. The Sencil platform can be adapted to detect other analytes in interstitial fluids.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.