Implantable Pressure Sensor with Oil-Filled Protective Chamber
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current implantable intraocular pressure (IOP) sensors have a short lifespan due to sensor drift caused by chemo-biological factors like hydrolytic corrosion and biofouling, leading to inaccurate measurements and frequent recalibration, while pressure relief devices also suffer from biofouling issues, resulting in inadequate monitoring and treatment of glaucoma.
Innovation Solution
An implantable pressure sensor apparatus with an oil-filled bag or pliable membrane protecting the sensor, combined with a drainage tube and flow restrictor, is mounted outside the eyeball with cannulas entering through the pars plana, using biocompatible materials and designs that minimize biofouling and drift, such as silicone oil and parylene membranes, along with a flexible PCB and wireless transmitter for continuous monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an implantable IOP sensor is used for continuous monitoring, then measurement accuracy and reliability are improved, but sensor lifespan deteriorates due to sensor drift from hydrolytic corrosion and biofouling
Solution Approach 1:
The sensor system is divided into separate functional components: the pressure sensing element, the fluid communication pathway (cannula), and the housing. This segmentation allows the sensing membrane to be protected from direct exposure to ocular fluids while maintaining pressure measurement capability through the fluid column in the cannula.
Solution Approach 2:
A biocompatible fluid (such as saline or ocular humor) serves as an intermediary medium, transmitting pressure from the ocular environment through the cannula to the sensing membrane. This intermediary protects the sensor from direct contact with biofouling-prone ocular fluids while maintaining accurate pressure transmission.
2Reliability
If a drainage tube is implanted to relieve IOP, then pressure relief function is improved, but reliability deteriorates due to frequent biofouling and clogging
Solution Approach 1:
The system combines multiple functions into a single integrated device: the housing serves as both the sensor protection enclosure and the drainage tube, while the cannula serves as both the pressure sensing conduit and the drainage pathway. This multi-functionality reduces the number of separate components that could become fouled.
Solution Approach 2:
The flow restrictor is designed to be serviceable through the housing, allowing clinicians to access and clean or replace the restrictor without removing the entire implanted device. This self-service capability enables maintenance of the drainage function while the device remains in place.
3Speed
If the sensor membrane is directly exposed to bodily fluids for pressure sensing, then sensing responsiveness is improved, but sensor stability deteriorates due to hydrolytic corrosion and biofouling
Solution Approach 1:
A biocompatible fluid column in the cannula acts as an intermediary, transmitting pressure changes from the ocular environment to the sensing membrane without requiring direct contact between the membrane and ocular fluids. This maintains sensing responsiveness while protecting membrane stability.
Solution Approach 2:
The housing incorporates a flexible, biocompatible membrane that seals the interior while allowing pressure transmission. This thin film protects the internal sensing components from direct exposure to ocular fluids while maintaining pressure sensitivity.
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 provides a reliable, long-term monitoring and drainage system that maintains clinical accuracy, reduces biofouling, and allows for continuous IOP monitoring, enhancing the diagnosis and treatment of glaucoma by preventing preventable vision loss.
Implementation Method 1
an oil chamber encapsulating the pressure sensitive membrane, the oil chamber filled with a biocompatible oil and having a pliable membrane on at least one side
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
A miniature, low power electronic pressure sensor with a first, oil-filled chamber to protect its microelectromechanical systems (MEMS) pressure sensitive membrane and a second chamber filled with saline or body fluids connected by tube into an organ in the body, such as an eyeball, that needs pressure sensing, is described. The tube carries pressure from a sensitive area within the organ to the electronic pressure sensor. The pressure sensor may communicate wirelessly with external readers and pass data to a server or other computer. Running alongside the tube is another tube for draining and pressure relief. The tubes, or cannulas, can share an opening into the organ in order to minimize the number of holes needed. The tubes may be molded into a single oval cross section, combined coaxially, or share a lumen for a portion that enters the wall of an organ so as to promote healing.