Capacitive Syringe Sensing for Battery-Free Injection Status Tracking

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Solution Overview

Problem

Drug delivery devices lack features for accurately detecting and communicating injection status, particularly in clinical trials where timely and appropriate administration of medicaments is critical.

Innovation Solution

A drug delivery device equipped with a capacitive element and a short-range communication device, such as NFC, measures capacitance changes to determine injection status and communicate this information to stakeholders without the need for physical contact or batteries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If traditional drug delivery devices are used without sensor assemblies, then the device complexity is low and manufacturing cost is reduced, but the ability to detect and communicate injection status is lost

Engineering Contradiction:

Improveinjection status informationVSAvoiddevice complexity

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The patent replaces mechanical observation methods with electronic sensing. A capacitive sensor assembly detects plunger rod position and composition presence through electrical fields, substituting mechanical visualization with electronic detection and wireless communication of injection status.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The sensor assembly serves multiple functions: detecting plunger rod position, determining composition presence, and communicating status wirelessly. This multi-functionality addresses information loss while adding only one modular component to the device.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Loss of information

If communication devices are added to drug delivery devices, then the ability to communicate injection status is improved, but the manufacturing cost increases

Engineering Contradiction:

Improvedrug delivery informationVSAvoidmanufacturing cost

Core Design Contradiction:

Loss of informationVSEase of manufacture

Solution Approach 1:

The patent employs a disposable sensor assembly integrated with the drug delivery device. This single-use component includes capacitive sensors and wireless communication capability, providing accurate injection status tracking at minimal cost for the information gained.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The capacitive sensor assembly acts as an intermediary between the mechanical plunger rod and the wireless communication system. It converts physical position information into electrical signals that can be transmitted, enabling cost-effective communication without direct mechanical-to-digital conversion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If sensor assemblies are integrated into drug delivery devices, then the measurement precision of injection status is improved, but the device complexity increases

Engineering Contradiction:

Improveinjection status detection accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent places capacitive sensors at specific locations within the sensor assembly to detect local changes in the electrical field caused by the plunger rod position and composition presence. This localized sensing approach achieves precise measurement without requiring complex system-wide instrumentation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The capacitive sensors detect changes in electrical field parameters (capacitance values) as the plunger rod moves and composition is present or depleted. By monitoring these parameter changes, the system achieves precise injection status detection through simple capacitive measurements rather than complex mechanical encoders.

Inventive Principle:

Principle #35Parameter changes

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 accurate detection and communication of injection status, ensuring timely and appropriate administration of medicaments, particularly in clinical trials, without increasing device cost.

Implementation Method 1

a sensor assembly, including a capacitive element and a short-range communication device in electrical communication with the capacitive element, wherein the short-range communication device is capable of measuring capacitance at the capacitive element

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4285959B1Battery-free sensing solution for drug delivery devices

Publication Date: 2026.05.13 BECTON DICKINSON & CO

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Figure 2A

AI summary

Provided herein is a drug delivery device including a syringe barrel having a proximal end, a distal end, and a sidewall arranged between the proximal end and the distal end defining an interior configured to hold a composition, a plunger rod received at least partially within the interior of the syringe, the plunger rod having a proximal end, a distal end, and a stopper arranged at the distal end, and a sensor assembly, including a capacitive element and a short-range communication device in electrical communication with the capacitive element, wherein the short-range communication device is capable of measuring capacitance at the capacitive element.