Tapering Hexagonal Microprojection Arrays for Intradermal Vaccine Delivery
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Solution Overview
Problem
Current intradermal vaccine delivery methods face challenges such as inefficient targeting of immune cells, tissue damage, and mechanical difficulties in precise delivery due to the disparity in mechanical modulus of skin layers, limiting the effectiveness of vaccine administration.
Innovation Solution
The development of microprojection arrays with tapering hexagonal or octagonal microprojections that have a slight draught angle increasing to 70 degrees, allowing for deeper skin penetration with reduced energy requirements and enhanced immunogenic response by increasing cell death and antigen delivery to live cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional conical or cylindrical microprojection designs are used, then the device structure is simple, but skin penetration depth is limited and energy requirements are high
Solution Approach 1:
The patent changes the geometric parameters of microprojections from conventional conical or cylindrical shapes to tapering hexagonal or octagonal shapes with specific draught angles (1-20 degrees) transitioning to steeper angles (20-70 degrees). This parameter change optimizes the balance between skin penetration depth and energy requirements by creating a shape that concentrates force at the tip while maintaining structural integrity
Solution Approach 2:
The patent employs asymmetric tapering in the microprojection geometry where the draught angle varies along the length of the projection. The base portion has a slight draught angle (1-20 degrees) for structural stability, while the tip portion has a steeper angle (20-70 degrees) for effective skin penetration, creating an asymmetric profile that optimizes both penetration depth and energy efficiency
2Measurement precision
If microprojection arrays are used to deliver vaccines intradermally, then targeting of immune cells is improved, but tissue damage occurs due to mechanical stress
Solution Approach 1:
The patent applies local quality by creating microprojections with varying geometric properties along their length. The base has a larger cross-section for structural support and array stability, while the tip has a smaller cross-section with optimized angles for precise skin penetration. This local variation in geometry allows precise targeting of immune cells in the dermis while minimizing collateral tissue damage through controlled stress distribution
3Manufacturing precision
If the mechanical modulus disparity of skin layers is not addressed, then device design is simplified, but precise delivery to targeted depth is challenging
Solution Approach 1:
The patent addresses the mechanical modulus disparity of skin layers by optimizing the microprojection geometric parameters, specifically the draught angles. The transition from slight draught angles (1-20 degrees) at the base to steeper angles (20-70 degrees) at the tip creates a stress distribution pattern that facilitates sequential penetration through epidermis and dermis layers with different mechanical properties, achieving precise delivery without increasing device complexity
Data Source
AI summary
A microprojection array comprising a substrate with a plurality of microprojections protruding from the substrate wherein the microprojections have a tapering hexagonal shape and comprise a tip and a base wherein the base has two substantially parallel sides with a slight draught angle of approximately 1 to 20 degrees up to a transition point at which point the angle increases to from about 20 degrees to about 70 degrees.