Intraocular Pressure Sensor with Flexible Multilayer Coating
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Solution Overview
Problem
Existing intraocular pressure sensors implanted in the eye face challenges in accurately measuring pressure due to coatings that act as barriers, preventing precise sensing and quick reaction to pressure changes, while also being obstructive and causing adverse reactions.
Innovation Solution
A silicone gel layer is used on the sensing surface of an implantable pressure sensor, hermetically encapsulated within a flexible multilayer coating, which provides mechanical protection and adheres well to the sensor and surrounding tissue, allowing for accurate pressure measurement without damping and minimizing occlusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier coating is applied to protect the pressure sensor, then the sensor is protected from tissue damage, but the coating prevents accurate pressure sensing and quick reaction to pressure changes
Solution Approach 1:
The patent applies a flexible multilayer coating comprising alternating layers of Parylene C and SiOx that hermetically seals the pressure sensor while allowing accurate pressure transmission. The flexible nature of these thin films enables the coating to conform to the sensor surface and transmit pressure changes without significant damping, resolving the contradiction between protection and sensing accuracy.
Solution Approach 2:
The patent uses a composite multilayer coating structure combining Parylene C and SiOx materials. This composite approach leverages the complementary properties of each material - Parylene C provides flexibility and conformability while SiOx provides barrier properties - achieving both sensor protection and accurate pressure measurement simultaneously.
2Object-affected harmful factors
If a coating is applied to prevent adverse reactions, then biocompatibility is improved, but the coating becomes obstructive and causes vision blockage
Solution Approach 1:
The flexible multilayer coating is applied as an extremely thin film that provides biocompatibility and protection while remaining optically transparent. The thin film structure allows light to pass through without significant absorption or scattering, preventing vision blockage while still providing the necessary barrier function to prevent adverse tissue reactions.
Solution Approach 2:
The coating is applied locally only where necessary - on the sensor components and electronics - while leaving the optic zone of the intraocular lens clear and unobstructed. This localized application ensures biocompatibility and protection in areas where materials are present, while maintaining full optical clarity in the vision-critical optic region.
3Reliability
If the sensor is encapsulated for protection, then reliability is improved, but the sensor's sensitivity and response speed are compromised
Solution Approach 1:
The flexible multilayer coating is designed with sufficient thinness and flexibility to allow rapid pressure transmission while providing hermetic sealing. The flexible nature of the Parylene C and SiOx layers enables them to deform quickly in response to pressure changes, maintaining sensor response speed while providing durable protection against tissue encapsulation and degradation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables precise and responsive measurement of intraocular pressure without compromising the sensor's sensitivity or causing adverse reactions, ensuring clear vision and effective monitoring of glaucoma and post-operative conditions.
Implementation Method 1
A silicone gel layer is used on the sensing surface of an implantable pressure sensor... allowing for accurate pressure measurement without damping
Implementation Method 2
A silicone gel layer is used on the sensing surface of an implantable pressure sensor, hermetically encapsulated within a flexible multilayer coating
Implementation Method 3
A silicone gel layer is used on the sensing surface of an implantable pressure sensor... adheres well to the sensor and surrounding tissue
Data Source
AI summary
Implantable pressure sensors and implantable electronics should be packaged in hermetically sealed modules with biocompatible surfaces before being implanted. Packaging designs should be compact and cause little to no interference with the mechanical (and optical) properties or functions of the implant. For a pressure sensor in an intraocular lens, this means that the sensor and packaging should allow the lens to be folded so that it can be implanted through a small incision in the eye. An inventive implantable pressure sensor is coated with a silicone elastomer and hermetically sealed by a multilayer coating of SiOx and Parylene C, which may also encapsulate other components, including a microcontroller or processor, rechargeable batteries, sensors, resistors, capacitors, wireless transceivers, and/or antennas mounted on a transparent substrate. This combination of silicone gel and multilayer coating isolates the pressure sensor from surrounding tissue while allowing the pressure sensor to measure pressure precisely and quickly.