Microneedle Array Assembly Using Adhesive Substrate
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Solution Overview
Problem
Existing methods for producing microneedle arrays result in low density due to the proximity and securing of needles, making it difficult to achieve high density arrays using solid or hollow needles, particularly those made from stainless steel or other materials for cosmetic and drug delivery applications.
Innovation Solution
A method involving attaching microneedles to a substrate and building up a 2-dimensional array through layers, allowing for adjustable needle pitch and density by using a substrate with adhesive and alignment grooves, enabling the creation of high-density arrays without requiring sophisticated equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If needles are produced using fabrication techniques, then high needle densities are achieved, but tip sharpness and mechanical strength are compromised
Solution Approach 1:
The invention segments the needle array into individual solid needles that are separately manufactured and then assembled into an array. Each needle is produced using conventional solid material fabrication methods that ensure tip sharpness and mechanical strength, while the array assembly process achieves high needle densities through precise positioning and securing of individual needles.
2Quantity of substance
If solid or hollow needles are assembled at close proximities, then high density arrays are achieved, but the securing and placement process becomes complex
Solution Approach 1:
The invention introduces a substrate as an intermediary element that facilitates the assembly process. The substrate provides a base surface with features such as adhesive layers, grooves, or slots that enable precise placement and securing of individual needles at close proximities. This intermediary structure simplifies the assembly process by providing ready-made positioning mechanisms rather than requiring complex direct manipulation and securing of needles.
3Quantity of substance
If needle pitch is reduced to increase density, then higher needle density is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The invention applies preliminary action by pre-forming positioning features on the substrate before needle assembly. The substrate is prepared with adhesive layers, grooves, or slots at predetermined locations that specify the exact positions for needle placement. This preliminary preparation eliminates the need for high-precision real-time positioning during assembly, as needles are simply placed into pre-defined locations, thereby achieving high needle density with reduced manufacturing precision requirements.
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 method allows for the production of microneedle arrays with a significantly higher needle density, comparable to or smaller than the needle diameter plus adhesive/substrate thickness, facilitating improved drug delivery and diagnostic applications with enhanced mechanical strength and tip sharpness.
Implementation Method 1
using a substrate with adhesive and alignment grooves
Implementation Method 2
The alignment of the tips of the needles is achieved by having a flat surface against which the needle tips rest, either by gravity or by application of external force
Data Source
AI summary
Microneedle devices have projections that are generally sharp and elongated and designed to disrupt the upper layer of the skin, cause micro-indentations, or pierce the skin. High density arrays are produced using micro-fabrication or micro-molding techniques. The assembly of individual needles does not lend itself to the production of high density arrays. A method of forming microneedle arrays is disclosed which comprises attaching a plurality of microneedles to a substrate, and building up a 2-dimensional microneedle array by wrapping layers of the substrate around a core or folding the layers repeatedly back upon themselves. The arrays are capable of needle densities with a pitch within the range of needle radius plus several micrometers to millimeters.