Near Infrared Microsensor for Continuous In-vivo Intraocular and Intracranial Pressure Monitoring.

Implantable Wireless Sensor;Bio-Optics;Intracranial Pressure;Bio-MEMS;Glaucoma;Near Infrared;Biomedical Engineering;Engineering;Biomedical Engineering

Ghannad-Rezaie, MostafaYang, Lynda Jun-san ;

University of Michigan

关键词: Implantable Wireless Sensor;    Bio-Optics;    Intracranial Pressure;    Bio-MEMS;    Glaucoma;    Near Infrared;    Biomedical Engineering;    Engineering;    Biomedical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/97943/mostafa_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Pressure monitoring in the nervous system is widely used to evaluate therapeutic interventions in patients with severe pathological elevated pressure in the brain (such as traumatic brain injuries (TBI) and hydrocephalus) and in the eye (e.g. glaucoma). Monitoring the pressure has been shown to reduce the number of deaths in TBI patients by 20% and number of blindness in glaucoma patients by 50%. Continuous, long-term in-vivo pressure monitoring, therefore is a necessity for planning interventional treatment for the patients in the risk.The clinical method for monitoring the pressure is not changes in past 40 years. Non-invasive tonometer for glaucoma patients are inaccurate and cannot be used for continuous monitoring.Current invasive clinical pressure monitoring practices often employ a catheter that records the pressure surgically inserted in the brain or in the eye. These catheter-based systems have been successful so far in accurately monitoring pressure but they are not appropriate for long-term monitoring as: (i) the patient is continuously connected to the non-portable monitoring unit, and (ii) the long-term placement of the catheter significantly increases the risk of infection.Motivated by the need for frequent, long-term pressure monitoring and the lack of commercially available fully implantable microsensors, we developed a novel class of MEMS-based, pressure technology, termed ;;Near infrared Fluorescent-based Optomechanical (NiFO)’ pressure sensing technology. NiFO technology is based on a fully implantable, powerless, optical microsensor (the NiFO sensor) that converts physiological pressure into a two-wavelength optical signal in the near infrared (NI) spectrum.NiFO microsensors were microfabricated using silicon bulk micromachining and were shown to operate at a physiologically relevant pressure range (0-100mmHg). They have a maximum error of less than 15 % throughout their dynamic range and they are extremely photostable. We adapted the microsensor design to measure intracranial pressure (ICP) and intraocular pressure (IOP) and we demonstrated their in-vivo operation for over a month in sheep. We envision that the proposed NiFO sensing technology will inaugurate a new era in the development of implantable, electronic and power-free miniaturized devices that can be used in a variety of biomedical pressure monitoring applications.