Modified Microneedles for Painless Transdermal Electrochemical Detection
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Solution Overview
Problem
Current methods for on-body wearable devices to detect ions and (bio)molecules in real-time through transdermal analysis are invasive and require complex sample manipulation, often using needles that are not painless and not suitable for simultaneous detection in multiple biofluids.
Innovation Solution
The development of modified microneedles and needles that can be externally or internally converted into electrochemical sensors, integrated into a patch for painless transdermal detection using potentiometry and amperometry readouts, allowing for simultaneous detection in interstitial fluid and blood.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional needles are used for transdermal detection, then sample extraction is achieved, but the procedure becomes invasive and painful
Solution Approach 1:
The needle is divided into multiple segments: a biocompatible microneedle array for painless skin penetration, and a separate sensor component that is introduced into the hollow interior after insertion. This segmentation allows the microneedle to perform its function of reaching the target fluid without causing pain, while the sensor component provides the detection capability.
Solution Approach 2:
A conductive paste or mixture acts as an intermediary medium between the external sensor electrode and the biofluid. This intermediary allows electrical contact and sample interaction without requiring direct exposure of the sensor to the external environment, enabling painless yet effective transdermal detection.
2Measurement precision
If sensors are implanted inside the skin for in-situ measurement, then real-time detection is achieved, but the invasiveness increases
Solution Approach 1:
The device is segmented into a microneedle insertion component and a separate sensor component. The microneedle penetrates the skin to reach the target biofluid, while the sensor is introduced separately into the hollow microneedle interior, avoiding the need for deep surgical implantation while still achieving in-situ measurement capability.
Solution Approach 2:
The hollow microneedle structure serves dual purposes: it acts as both the penetration instrument and the delivery vehicle for the sensor. The microneedle itself provides the pathway for sensor introduction, eliminating the need for separate implantation procedures.
3Measurement precision
If complex sample manipulation is used for detection, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The biofluid automatically fills the hollow interior of the microneedle through capillary action or pressure differential after skin penetration, eliminating the need for external pumping or complex sample collection mechanisms. The system self-regulates sample acquisition.
Solution Approach 2:
The hollow microneedle structure serves multiple functions simultaneously: it acts as the penetration tool, the sample collection chamber, and the delivery vehicle for the sensor. This multi-functionality reduces the number of separate components needed for sample manipulation.
4Measurement precision
If traditional needle designs are used, then single fluid detection is achieved, but simultaneous multi-fluid detection is not possible
Solution Approach 1:
The device uses an array of multiple hollow microneedles rather than a single needle, allowing each microneedle to target different biofluids or different analytes within the same fluid. This segmented approach enables simultaneous multi-fluid or multi-analyte detection capability.
Solution Approach 2:
The hollow microneedle array platform is designed to accommodate different sensor types and configurations, enabling it to detect multiple different biofluids or multiple analytes within the same fluid type, providing universal detection capability across different biological samples.
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
The solution enables cost-effective, painless, and reproducible multi-analyte detection in both interstitial fluid and blood, improving the compatibility and accuracy of on-body wearable sensors for real-time monitoring.
Implementation Method 1
The method comprises modifying an external surface of at least one solid microneedle or needle to improve its conductivity and/or to provide a material compatible with a further chemical modification
Implementation Method 2
The microneedles and needles structured to act as sensors for different analytes are integrated in a patch that is suitable to be applied to the skin. Two different biofluids may be targeting simultaneously by microneedles and needles of different sizes, structures and designs integrated in the same skin patch.
Data Source
AI summary
The disclosure relates to two methods to modify microneedles and needles to transform them as electrochemical sensors for ions and biomolecules. The methods focus on microneedles and needles made of any material through an external and internal modification methods to provide the function as electrodes: the working electrode, (pseudo)counter electrode and/or (pseudo)reference electrode depending on the electrochemical readout. With the external modification method, any solid microneedle and needle can be individually transformed in either of the said electrodes. With the internal modification method, any hollow microneedle and needle can be individually transformed in either of the electrodes. The working electrode, (pseudo)counter electrode and or (pseudo)reference electrode can be simultaneously integrated into the same hollow microneedle or needle by internal compartmentation. Two different biofluids can be simultaneously targeted by microneedles and needles of different sizes, structures and fabricated by one or both methods when integrated in the same skin patch.