Ocular Microneedle Injection With Depth and Force Control
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Solution Overview
Problem
Existing methods for delivering substances to the posterior region of the eye, such as the suprachoroidal space, face challenges due to anatomical variations, difficulty in controlling needle depth, potential damage to the retina, and leakage of fluids, and require high injection forces that users are uncomfortable with.
Innovation Solution
A microneedle system with an energy storage member and actuation rod that adjusts force based on target tissue density, a hub for forming a fluid-tight seal, and an adjustment mechanism for precise needle insertion and length control, minimizing collateral damage and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional needles and syringes are used for direct injection into the eye, then effective drug delivery can be achieved, but significant safety risks and high injection forces are required
Solution Approach 1:
The injection system is divided into separate functional modules: a hub for positioning and sealing, a needle for penetration, and a syringe for fluid delivery. This segmentation allows each component to be optimized independently, with the hub providing stable anchoring and the needle providing precise, low-force penetration through the sclera
Solution Approach 2:
The hub acts as an intermediary between the user and the eye tissue. It provides a stable platform for needle insertion, distributes the insertion force, and creates a fluid-tight seal, thereby reducing the force required for needle penetration and improving safety
2Reliability
If needle insertion depth is increased to reach the suprachoroidal space, then effective drug delivery to the posterior region is achieved, but risk of retinal damage increases
Solution Approach 1:
The needle length is pre-adjusted to the optimal length before insertion. The hub is positioned on the cornea first, and then the needle is inserted to a predetermined depth that corresponds to the suprachoroidal space, avoiding over-penetration and retinal damage
Solution Approach 2:
The system replaces manual depth control with a mechanical depth control mechanism. The needle is coupled to the hub through a shaft, and the insertion depth is controlled by the rotation and positioning of the hub, providing precise and repeatable depth control
3Reliability
If injection force is increased to deliver medication to dense ocular tissue, then effective delivery is achieved, but user comfort deteriorates
Solution Approach 1:
The injection system provides dynamic force control. The hub can be rotated to different positions, and the needle insertion depth can be adjusted, allowing the system to adapt to different tissue densities and injection requirements, thereby maintaining user comfort while ensuring effective delivery
Solution Approach 2:
The system changes the parameters of needle insertion by allowing rotation of the hub to different angular positions and adjustment of needle length. This enables optimization of the insertion force for different tissue densities, reducing the force required for injection while maintaining delivery effectiveness
4Device complexity
If conventional injection methods are used, then simple delivery is achieved, but fluid leakage and anatomical variations are not addressed
Solution Approach 1:
The hub serves multiple functions: it acts as a positioning platform, creates a fluid-tight seal, provides needle support, and enables depth control. This multi-functionality addresses fluid leakage and anatomical variations without significantly increasing the overall complexity of the injection system
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 precise delivery of substances to the suprachoroidal space with reduced force requirements, minimizes tissue damage, and prevents leakage, improving treatment efficacy and user comfort.
Implementation Method 1
The energy storage member is configured to produce a force on a proximal end portion of the actuation rod. The force is sufficient to move the distal end portion of the actuation rod within the medicament container to convey at least a portion of a substance from the medicament container via the needle
Implementation Method 2
a hub for forming a fluid-tight seal
Data Source
AI summary
An apparatus includes a housing coupled to a medicament container, which is coupled to a needle. An injection assembly is disposed within the housing and includes an energy storage member and an actuation rod. A distal end portion of the actuation rod is disposed within the medicament container. The energy storage member can produce a force on a proximal end portion of the actuation rod sufficient to move the distal end portion of the actuation rod within the medicament container. This can convey at least a portion of a substance from the medicament container via the needle when a distal tip of the needle is disposed within a first region of a target location. The force is insufficient to move the distal end portion of the actuation rod within the medicament container when the distal tip of the needle is disposed within a second region of the target location.