Retractable-Needle Delivery Device for Controlled Cell Ejection
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Solution Overview
Problem
Conventional delivery devices experience issues such as unwanted backflow of therapeutic substances, cell settling, rapid ejection rates causing damage to cells, and wastage of therapeutic substances due to long travel paths and non-smooth transitions.
Innovation Solution
A delivery device with a positive displacement mechanism where the needle retracts while the plunger advances, reducing backflow, and features a constant diameter needle lumen to minimize cell settling and allow controlled ejection rates, along with front-loading and air venting to reduce waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional delivery device uses a long needle and syringe for cell-based therapeutic administration, then the therapeutic substance can be delivered to a specific site bypassing body defense barriers, but cell settling occurs and cell viability is reduced due to rapid ejection rates
Solution Approach 1:
The needle is designed to be retractable, moving dynamically from an extended delivery position to a retracted safe position. This dynamic configuration allows the needle to reach the target site for accurate delivery while minimizing cell settling and damage during the delivery process by reducing the effective delivery path length.
Solution Approach 2:
The device controls the ejection rate by adjusting the plunger movement speed and needle retraction speed. By changing these parameters, the system delivers cells at a controlled, slow rate that maintains cell viability while still achieving accurate delivery to the specific target site.
2Device complexity
If the needle remains stationary during substance delivery, then simple device structure is maintained, but unwanted backflow of therapeutic substances occurs
Solution Approach 1:
The needle dynamically retracts during the delivery process while the plunger advances. This relative motion creates a unidirectional flow that prevents backflow of the therapeutic substance while maintaining a relatively simple device structure without requiring additional valves or complex mechanisms.
3Ease of manufacture
If the needle lumen has varying diameter with smooth transitions, then ease of manufacture is improved, but cell settling occurs in non-uniform flow paths
Solution Approach 1:
The needle lumen is designed with a constant diameter specifically in the critical delivery region to ensure uniform cell flow and prevent settling. This local quality adjustment addresses the cell delivery requirement while the overall needle structure remains simple to manufacture.
4Quantity of substance
If the plunger travels a long distance through the needle lumen, then complete delivery of therapeutic substance is achieved, but wastage of therapeutic substances increases due to long travel path
Solution Approach 1:
The needle retracts simultaneously with plunger advancement, effectively reducing the travel path length of the therapeutic substance. This dynamic adjustment ensures complete delivery of the therapeutic substance while minimizing wastage by shortening the distance the substance must travel through the needle lumen.
Data Source
AI summary
A delivery device for delivering, for example, a therapeutic substance, that includes a needle having a needle lumen and a plunger that is configured to move through the needle lumen; a first translation screw attached to the needle and positioned within a first threaded passage; a second translation screw attached to the plunger and positioned within a second threaded passageway; and a device actuator. Actuation of the device actuator causes rotation of the first threaded passage and rotation of the second threaded passage, which causes the first translation screw to translate through the first threaded passage and move the needle and causes the second translation screw to translate through the second threaded passage and move the plunger through the needle lumen.