In this proposal we propose to combine the expertise of the two research centres involved (photonics engineering at UPC-CD6 plus OFI sensors in LAAS-CNRS) to develop a novel type of blood flow sensor, as a first practical approach to the general use of optical feedback interferometry for biosensing. Biosensors, applied to telemedicine or security, are evolving towards compact, strong, and non-invasive (ideally non-contact) miniaturized items. Laser OFI sensors measure changes in the optical path of the laser, just by pointing it on the target, enabling to detect minute changes in it. OFI sensors are thus very adequate for modern biosensing as accurate, non-contact, compact and noninvasive probes without any complex optical alignment step, and very cost effective.

OFI based sensors have been recently applied for many applications including measurement of displacement, velocity, absolute distance, surface profile, physical quantities and biomedical applications like measurements of arterial pulse shape, blood cell velocity distribution in micro-channels, blood flow, and muscle vibration. 

We plan to advance in the use of OFI sensor for bio-sensing applications, by using a microscope objective as a part of optical configuration to control the dimensions of the spot on the target, including the capability of real-time laser feedback control appropriate for achieving the optimum measurement condition. Prospective applications include:  Tumor monitoring and angiogenesis, Diabetes research, Dermatology, Peripheral Vascular Disease, Intra-cranial monitoring in stroke and brain injury, and Gastroenterology.

The expected results consist of:
• Modelling of the sensing volume and its effects on OFI signal, validate using the experimental setup described next.
• Development of a new optical setup appropriate for controlling the illumination on the sample and sensing volume with the ability of the feedback level adjustments in OFI measurements. Includes design and construction of such a setup.
• An OFI-based sensor for experimental measurements of the concentration of blood particles, blood flow distribution and profile, and blood flow rate using the OFI based sensor with the new optical system. All experiments should be performed in real-world conditions, and being as non-invasive and cost-effective as possible.
• Repeatability and reliability measurements of the sensor obtained.

The project has been funded by the EU Commission under the program TECNIOSpring of ACC1Ó.