Concentric Flow Injection Device for Cell Viability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current injection devices, such as syringes, cause significant cell death during the injection of biological materials due to excessive shear rates experienced by cells as they pass through small-bore needles, leading to low cell viability rates and reduced effectiveness of therapies like stem cell therapies.
Innovation Solution
An injection device with a dual-barrel design, where a first barrel containing biological cells is surrounded by a second barrel's fluid in a concentric flow, minimizing shear rates by using a lubricating fluid like phosphate-buffered saline to reduce mechanical stress on the cells, and optimizing the device's geometry to maintain a low shear rate throughout the injection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If small-bore needles are used to reach target therapeutic areas, then the ability to access deep or precise locations is improved, but cell viability deteriorates due to high shear rates
Solution Approach 1:
A lubricating fluid is introduced as an intermediary substance between the cell-containing fluid and the needle wall. This lubricating fluid reduces the shear rate experienced by cells during injection through small-bore needles, thereby maintaining cell viability while enabling access to target therapeutic areas that require small-bore needles.
Solution Approach 2:
The viscosity of the carrier fluid is modified by adding a lubricating agent, changing the rheological parameters of the fluid. This parameter change reduces the shear rate at the needle wall during injection, allowing small-bore needles to be used without causing excessive cell damage, thus maintaining both adaptability and reliability.
2Device complexity
If conventional single-barrel syringes are used, then device complexity is minimized, but cell damage due to shear effects increases
Solution Approach 1:
The syringe is segmented into two separate barrels: one containing the cell-containing fluid and another containing the lubricating fluid. This segmentation allows each fluid to be delivered independently and simultaneously, enabling the lubricating fluid to protect cells from shear damage while maintaining a relatively simple overall device structure.
Solution Approach 2:
The lubricating fluid is delivered in a concentric manner around the cell-containing fluid, creating a nested flow pattern. The inner barrel delivers the cell fluid through a central channel, while the outer barrel delivers the lubricating fluid in an annular region, nesting the protective function around the vulnerable cells.
3Productivity
If high injection velocities are used to maintain productivity, then injection speed is improved, but shear rate increases causing cell death
Solution Approach 1:
The lubricating fluid serves as a mediator that decouples the relationship between injection velocity and shear rate. By introducing this intermediary layer, higher injection velocities can be used to maintain productivity without proportionally increasing the shear rate experienced by cells, thus improving cell survival rates while maintaining injection speed.
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
This design significantly improves cell viability rates by minimizing shear-induced damage, potentially achieving 85% or greater cell survival during injection, while maintaining low injection velocities suitable for clinical and bioplotting applications.
Implementation Method 1
produce a concentric flow of the first fluid within the second fluid
Implementation Method 2
minimises the shear rate experienced by the first fluid
Implementation Method 3
using a lubricating fluid like phosphate-buffered saline to reduce mechanical stress on the cells
Data Source
AI summary
An injection device comprising: a first barrel for containing a first fluid, and having a first plunger; a second barrel for containing a second fluid, and having a second plunger, the second barrel being arranged to one side of the first barrel; a flow converging chamber in fluid communication with the second barrel, for receiving, in use, a flow of the second fluid from the second barrel when the second plunger is advanced within the second barrel; a first inlet to the flow converging chamber, in communication with the first barrel, for receiving, in use, a flow of the first fluid from the first barrel when the first plunger is advanced within the first barrel, simultaneously with the advancement of the second plunger, and arranged to introduce the flow of the first fluid in a concentric manner within the flow of the second fluid, at a meeting point within the flow converging chamber, to produce a concentric flow of the first fluid within the second fluid; and an outlet of the flow converging chamber, for outwardly delivering the concentric flow of the first fluid within the second fluid. The first fluid may contain biological materials such as cells, and may for example comprise a hydrogel. The second fluid may comprise an aqueous fluid such as phosphate-buffered saline. Also provided is a method of delivering a concentric flow of a first fluid within a second fluid, using such an injection device.