Injection Needle Array to Prevent Wheal Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing injection needles with microneedles face challenges in efficiently injecting liquids into the skin due to the formation of wheals, which can lead to liquid leakage or difficulty in entering the body, especially with larger volumes.
Innovation Solution
The injection needle design includes a first projection with a conical shape and an opening at the distal end, surrounded by second projections that do not have an opening, arranged in a specific pattern to minimize skin suppression and allow efficient liquid injection by providing space for skin rise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If microneedles are used for intradermal injection, then pain is significantly reduced, but liquid leakage occurs due to wheal formation
Solution Approach 1:
The injection needle is divided into multiple fine needle-like projections (microneedles) arranged in an array, with each projection independently penetrating the skin. This segmentation allows the liquid to be distributed across multiple insertion points, preventing wheal formation and leakage while maintaining low pain levels.
Solution Approach 2:
The projections are designed with specific local characteristics: fine needle-like tips for painless penetration, hollow interiors for liquid delivery, and controlled spacing to allow skin rise. This local quality optimization ensures reliable liquid injection without the harmful wheal formation effect.
2Quantity of substance
If larger volumes of liquid are injected, then treatment effectiveness increases, but liquid leakage worsens due to wheal formation
Solution Approach 1:
The liquid volume is segmented across multiple projection tips simultaneously. By distributing the total injection volume across many fine projections, the patent prevents localized skin over-distension that causes wheal formation and leakage, enabling reliable delivery of larger total volumes.
Solution Approach 2:
The injection approach transitions from a single-point penetration to a two-dimensional array of projections. This dimensional change allows the liquid to be dispersed over a larger surface area, preventing the accumulation that leads to wheal formation and enabling scalable volume delivery.
3Manufacturing precision
If projections are arranged closely together, then injection precision is improved, but skin rise is suppressed reducing injection efficiency
Solution Approach 1:
The projection array is designed with optimized local spacing that balances precision and skin rise. The projections are positioned at specific intervals that are close enough for precise targeting but far enough to allow the skin to rise between them, ensuring both injection precision and efficiency.
Solution Approach 2:
The spacing parameter between projections is optimized to a specific range. By adjusting this geometric parameter, the patent achieves the dual benefit of sufficient precision for accurate delivery while maintaining enough space for skin rise, thereby preserving injection efficiency.
Data Source
Figure 1~2
Figure 3(a)~4
Figure 5
AI summary
An injection needle includes first and second projections (11, 12); wherein the first projection and the second projection each are fine and protrude from a sheet base portion (2), the first projection (11) has a conical shape and includes an opening (11a) in a distal end portion thereof, the second projection (12) does not include an opening in a distal end portion thereof, and the first projection and the second projection each have a protruding height of 5000 µm or less. The injection needle includes a first region (R1) and a second region (R2) in plan view; wherein first region (R1) includes one or two or more first projections (11); the second region (R2) includes two or more second projections (12); and the second region (R2) surrounds the first region (R1) or the second regions (R2) sandwich the first region (R1). A distance (D1), which is the shortest distance among distances between the first projection (11) and the second projections (12), is from 2.0 mm to 10 mm.