Optical Force Measurement in Cardiac Tissue Bioreactor
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Solution Overview
Problem
Current bioreactor systems for growing cardiac tissue strips face limitations such as non-isometric force measurement, inability to stretch tissues to optimal length, high expense, low throughput, and tissue damage due to clamping, making it difficult to compare data with traditional muscle bath systems.
Innovation Solution
A bioreactor system that integrates mechanical and electrical stimulation, automated contractile force measurement, and media perfusion, allowing for the growth of multiple tissue strips in parallel while maintaining optimal incubator conditions, with features like fiber-optic tension sensors and position-sensitive detectors for real-time data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PDMS cantilever platform with optical tracking is used for force measurement, then non-invasive real-time measurement is achieved, but force measurement accuracy is reduced due to non-isometric conditions and mechanical unloading
Solution Approach 1:
The patent replaces the mechanical PDMS cantilever system with an optical measurement system using a position-sensitive detector (PSD) and laser beam. The laser beam reflects off a mirror attached to the tissue strip, and the PSD tracks the beam position to measure force, eliminating mechanical contact and unloading effects while maintaining non-invasive real-time measurement capability
Solution Approach 2:
The patent introduces a mirror as an intermediary element attached to the tissue strip. The mirror reflects the laser beam to the PSD, serving as a mediator that transmits mechanical displacement information from the tissue to the optical detection system without requiring direct mechanical contact between the measurement system and the tissue
2Measurement precision
If muscle bath systems are used for force testing, then isometric force measurement is achieved, but system cost and complexity increase significantly
Solution Approach 1:
The patent replaces the complex mechanical muscle bath system with a simplified optical measurement system. Instead of using mechanical transducers, clamps, and fluid baths, the invention uses a laser beam, mirror, and position-sensitive detector to achieve isometric force measurement, dramatically reducing mechanical complexity while maintaining measurement accuracy
Solution Approach 2:
The patent extracts and eliminates the unnecessary mechanical components of traditional muscle bath systems (clamps, fluid baths, mechanical transducers) and retains only the essential measurement function through the optical system, simplifying the overall device while preserving isometric measurement capability
3Reliability
If traditional muscle bath systems are used, then tissue clamping is achieved for secure mounting, but tissue damage occurs due to clamping forces
Solution Approach 1:
The patent replaces mechanical clamping with optical attachment. A mirror is attached to the tissue strip using non-mechanical means (such as adhesive or integration into the hydrogel matrix), and the optical system measures force without applying clamping forces to the tissue, eliminating damage while maintaining stable mounting
Solution Approach 2:
The mirror serves as an intermediary that attaches to the tissue without requiring strong mechanical clamps. The mirror can be integrated into the hydrogel matrix or attached with minimal interference, providing stable mounting while avoiding the high clamping forces that cause tissue damage in traditional systems
4Productivity
If automated bioreactor system is implemented, then throughput and efficiency are improved, but system cost and complexity increase
Solution Approach 1:
The patent designs the bioreactor system to perform multiple functions: tissue culture, mechanical stimulation, electrical stimulation, and force measurement all within a single integrated platform. The optical measurement system serves both as a research tool and a quality control mechanism, enabling high-throughput screening while maintaining tissue viability for extended periods
Solution Approach 2:
The system incorporates automated media perfusion, environmental control, and data collection that operate without continuous manual intervention. The optical measurement system continuously monitors tissue force generation automatically, and the bioreactor maintains optimal culture conditions autonomously, reducing labor requirements while increasing throughput
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
Enables high-content, biofidelic, non-destructive testing of engineered muscle tissue performance, providing accurate and efficient data collection without the need for manual interaction, and allowing for controlled mechanical and electrical stimulation.
Implementation Method 1
a fiber-optic tissue post that acts as a light guide to a position-sensitive detector
Implementation Method 2
The position-sensitive detector receives light transmitted through the fiber-optic tissue post and detects the position of a light spot
Implementation Method 3
A video platform to optically track the displacement of the ends of the post due to bending enables the tissue-generated contractile force to be estimated non-invasively and in real-time using the bending equation for a cantilever beam
Data Source
AI summary
An improved tissue engineering bioreactor and testing platform has been designed that integrates multiple testing and stimulation capabilities. The system allows for growth of multiple tissue strips in parallel with mechanical and electrical stimulation, media perfusion, and the automated monitoring of contractile force and extracellular electrical activity. The system is designed to be low-cost and scalable, to provide for high-content, biofidelic, non-destructive testing of engineered muscle tissue performance that is conventionally measured using muscle-bath systems.