Noncircular Test Loops With Reciprocating Flow for Low-Hemolysis Testing
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Solution Overview
Problem
Existing flow-based biological testing platforms struggle to accurately simulate physiological conditions, minimize background noise, and reduce hemolytic damage while providing controlled fluid flow for evaluating biocompatibility of medical devices, failing to meet FDA guidelines and comprehensive evaluation needs.
Innovation Solution
A flow-based biological testing platform with a stationary base, reciprocating base, and flexible tubular test loops, featuring a single check valve and fluid loading system, which induces fluid flow through linear reciprocating motion, minimizing background noise and hemolytic damage, and allowing for simultaneous operation of multiple loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a Chandler loop with air gap is used to create flow, then fluid flow is generated, but air-blood interaction causes activation and departs from physiological conditions
Solution Approach 1:
The invention extracts and removes the air gap component from the testing system. By eliminating the air-blood interface entirely and using a completely fluid-filled loop design, the harmful air-blood interaction activation is removed while flow is still generated through alternative means (roller pump or gravitational drainage).
Solution Approach 2:
The invention introduces a roller pump as an intermediary device to generate fluid flow without requiring an air gap. The roller pump mechanically drives fluid circulation through the loop, replacing the gravitational flow mechanism that required air-blood interface, thereby eliminating activation while maintaining physiological flow conditions.
2Object-affected harmful factors
If a Wolf loop with check valve is used to prevent backward flow, then hemolytic damage is reduced, but the whole loop must move requiring platform to be stopped for sampling
Solution Approach 1:
The invention segments the testing loop into stationary and mobile portions. The sampling ports are positioned in the stationary portion of the loop, allowing samples to be accessed without moving the entire loop or stopping the platform. This enables continuous operation while maintaining the benefits of the check valve design.
Solution Approach 2:
The stationary sampling ports are designed to allow the system to serve itself by enabling sample collection without external intervention or platform interruption. The design inherently provides continuous access to flowing blood samples while the loop remains in motion.
3Speed
If roller pump is used to drive fluid flow, then controlled flow is achieved, but significant hemolytic damage and activation occur
Solution Approach 1:
The invention replaces the roller pump mechanical system with a gravitational flow system. By positioning the fluid reservoir above the testing section, gravity naturally drives fluid flow through the loop, eliminating the need for mechanical pumping and thereby preventing roller-induced hemolytic damage and activation.
4Device complexity
If circular test loop is used for testing, then simple design is achieved, but background noise is high and physiological simulation is inaccurate
Solution Approach 1:
The invention changes the loop geometry from a symmetric circular design to an asymmetric configuration with distinct vertical and horizontal sections. The vertical section allows gravitational flow, while the horizontal testing section provides a stable, noise-minimized environment for accurate measurements. This asymmetric design reduces background noise while maintaining simplicity.
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 platform achieves precise simulation of physiological conditions, reduces background noise to less than 15%, minimizes hemolytic damage, and supports comprehensive evaluation of biocompatibility, aligning with FDA guidelines and facilitating high-throughput testing of medical devices.
Implementation Method 1
The blood in the Wolf loop platform is moved forward by inertia and is prevented from backward flow by at least one check valve
Implementation Method 2
each test loop includes at least one check valve mounted within the test loop allowing flow in a single flow direction within the test loop
Implementation Method 3
As the turntable spins, gravity keeps the fluid at the bottom of the tube, creating flow
Data Source
AI summary
A flow-based biological testing platform comprises a stationary base; a reciprocating base mounted on the stationary base, configured for reciprocating motion on the base; and at least one flexible tubular test loop coupled to both the stationary and the reciprocating base, wherein each test loop is configured to be selectively filled with a biologic fluid, and wherein each test loop includes at least one check valve mounted within the test loop allowing flow in a single flow direction within the test loop, and a fluid loading and removal system attached to the stationary base allowing fluid to be supplied to and withdrawn from the flexible tubular test loop; wherein reciprocation of the reciprocating base induces fluid flow in a single direction within each flexible test loop.