We report the development of an optical fibre probe which could find use as an aid for margin detection during surgery. A fluorophore doped polymer is coated on an optical fibre tip, allowing for pH values of unknown tissue to be measured and compared to healthy tissue, to discriminate between healthy and cancerous tissue.<p> </p>This probe is integrated within a portable system, requiring no alignment or access to specialised vibration damped optical tables. A miniature spectrometer allows for measurements to be performed on-site, opening up the potential for use of these probes within the operating theatre for in-vivo measurements.
Reactive Oxygen Species (ROS) cause DNA damage and defective function in sperm and also affects the developmental competence of embryos. It is therefore critical to monitor ROS in sperm, oocytes and developing embryos. In particular, hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) is a ROS important to normal cell function and signalling as well as its role in oxidative stress. Here we report the development of a fluorescent sensor for H<sub>2</sub>O<sub>2</sub> using carboxyperoxyfluor-1 (CPF1) in solution and attached to a glass slide or multi-mode optical fibre. CPF1 increases in fluorescence upon reaction with H<sub>2</sub>O<sub>2</sub> to non-invasively detect H<sub>2</sub>O<sub>2</sub> near developing embryos. These probes are constructed by immobilising CPF1 to the optical fibre tip a polyacrylamide layer. Also reported is a new dual optical fibre sensor for detecting both H<sub>2</sub>O<sub>2</sub> and pH that is functional at biologically concentrations of H<sub>2</sub>O<sub>2</sub> and can sense pH to 0.1 units. This research shows promise for the use of optical fibre sensors for monitoring the health of developing embryos. Furthermore, these sensors are applicable for use beyond embryos such as detecting stress in endothelial cells involved in cardiovascular dysfunction.
Incomplete removal of malignant tumours continues to be a significant issue in cancer surgery. It increases the risk of local recurrence and impaired survival, and results in the need for additional surgery with associated attendant costs and morbidity. While pathological methods exist to determine tissue type during surgery, these methods can compromise post-operative pathology, have a lag of minutes to hours before the surgeon receives the results of the tissue analysis and are restricted to excised tissue.<p> </p>In this work we report the development of an optical fibre probe which could find use as an aid for margin detection during surgery. A fluorophore doped polymer coating is deposited on the tip of an optical fibre, which can then be used to record the pH by monitoring the emission spectra from the embedded indicator. The pH values of unknown tissue are measured and compared to healthy tissue, allowing for discrimination between healthy and cancerous tissue.<p> </p>The probe developed here shows strong potential for use during surgery, as the probe design can be readily adapted to a low-cost portable configuration which could find use in the operating theatre. Use of this probe in surgery either on excised or in-vivo tissue has the potential to improve success rates for complete removal of cancers.
The production of reactive oxygen species (ROS) is known to affect the developmental competence of embryos. Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) an important reactive oxygen species, is also known to causes DNA damage and defective sperm function. Current techniques require incubating a developing embryo with an organic fluorophore which is potentially hazardous for the embryo. What we need is a localised ROS sensor which does not require fluorophores in solution and hence will allow continuous monitoring of H<sub>2</sub>O<sub>2</sub> production without adversely affect the development of the embryo. Here we report studies on such a fibre-based sensor for the detection of H<sub>2</sub>O<sub>2</sub> that uses a surface-bound aryl boronate fluorophore carboxyperoxyfluor-1(CPF1). Optical fibres present a unique platform due to desirable characteristics as dip sensors in biological solutions. Attempts to functionalise the fibre tips using polyelectrolyte layers and (3-aminopropyl)triethoxysilane (APTES) coatings resulted in a limited signal and poor fluorescent response to H<sub>2</sub>O<sub>2</sub> due to a low tip surface density of the fluorophore. To increase the surface density, CPF1 was integrated into a polymer matrix formed on the fibre tip by a UV-catalysed polymerisation process of acrylamide onto a methacrylate silane layer. The polyacrylamide containing CPF1 gave a much higher surface density than previous surface attachment methods and the sensor was found to effectively detect H<sub>2</sub>O<sub>2</sub>. Using this method, biologically relevant concentrations of H<sub>2</sub>O<sub>2</sub> were detected, enabling remote sensing studies into ROS releases from embryos throughout early development.