A Magnetically Controlled Wireless Optical Oxygen Sensor for Intraocular Measurements

Abstract

Abstract-The influence of oxygen on various ophthalmological complications is not completely understood and intraocular oxygen measurements are essential for better diagnosis and treatment. A magnetically controlled wireless sensor device is proposed for minimally invasive intraocular oxygen concentration measurements. This device will make it possible to make measurements at locations that are currently too invasive for human intervention by integrating a luminescence optical sensor and a magnetic steering system. The sensor works based on quenching of luminescence in the presence of oxygen. A novel iridium phosphorescent complex is designed and synthesized for this system. A frequency-domain lifetime measurement approach is employed because of the intrinsic nature of the lifetime of luminescence. Experimental results of the oxygen sensor together with magnetic and hydrodynamic characterization of the sensor platform are presented to demonstrate the concept. In order to use this sensor for in vivo intraocular applications, the size of the sensor must be reduced, which will require an improved signal-to-noise ratio.

Recent Developments in the Application of Phosphorescent Iridium(III) Complex Systems

“…[34,84,[246][247][248] An experimental array for the measurement of oxygen concentration with respect to medicinal applications, i.e., for intraocular measurements, was recently introduced by Nazeeruddin and co-workers. [249] Since the oxygen concentration is in general related to sudden changes in the luminescence of the Ir III complex, new materials with high quantum yields and long excited-state lifetimes (i.e., up to several microseconds) for reliable, sensitive detection are the focus of current research. [9] Among others, mixed-ligand iridium(III) complexes are highly promising candidates, due to their well-tunable excited state properties, high durability, and stability towards the generated singlet oxygen.…”

Wireless Microrobotic Oxygen Sensing for Retinal Hypoxia Monitoring

“…In this paper, a method to functionalize mobile microrobots for intraocular oxygen sensing is presented. The research builds on [7] and proposes luminescence-based oxygen sensing using thin-films. The sensors used in [7] are further miniaturized and the readout setup is improved to utilize smaller microrobot sensors.…”

“…The research builds on [7] and proposes luminescence-based oxygen sensing using thin-films. The sensors used in [7] are further miniaturized and the readout setup is improved to utilize smaller microrobot sensors. The coated microrobots are used in an experimental setup that acts as a human-eye phantom (Fig.…”

OctoMag: An electromagnetic system for 5-DOF wireless micromanipulation

“…These untethered devices can navigate in bodily fluids to enable a number of new minimally invasive therapeutic and diagnostic medical procedures. We are particularly interested in intraocular microrobots, which have the potential to be used in ophthalmic procedures such as drug delivery and remote sensing [1]. One particularly difficult procedure for vitreoretinal surgeons to perform is retinal-vein cannulation-the injection of a clotbusting enzyme into a tiny vein-which is at the limits of human capabilities [2].…”