Capillary Microcuvette Dual Inlet Design for Flexible Sample Loading

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Solution Overview

Problem

Conventional microcuvettes are inconvenient for sample loading, particularly for blood samples, as they require direct fingertip contact with a narrow sample inlet, making it difficult to use blood from collection tubes and increasing the risk of biohazardous spills and contamination.

Innovation Solution

A microcuvette design with a capillary inlet and sample slot that allows for direct loading from fingertips or using a pipette, featuring a cavity width that decreases from the capillary inlet to the sample slot, enabling capillary action for specimen flow, and a narrower gap at the detection zone to prevent air bubble trapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a narrow sample inlet is used in conventional microcuvettes, then the device structure is simple, but the ease of operation deteriorates because direct fingertip contact is required and it is difficult to use with collection tubes

Engineering Contradiction:
Improveease of sample loadingVSAvoiddevice structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The sample inlet is divided into two distinct parts: a capillary inlet for direct fingertip contact and a sample slot for pipette loading. This segmentation allows the device to accommodate different sample loading methods without requiring a single complex inlet structure, thereby improving ease of operation while maintaining reasonable structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The microcuvette is designed with dual functionality at the sample inlet: it can accept both direct fingertip contact through the capillary inlet and pipette injection through the sample slot. This multi-functionality makes the device universally applicable to different sample collection scenarios, including both direct capillary sampling and laboratory-based pipetting from collection tubes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If direct fingertip contact with the sample inlet is required, then the device structure remains simple, but the reliability deteriorates due to increased risk of biohazardous spills and contamination

Engineering Contradiction:
Improvebiohazard safetyVSAvoidinlet structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

By segmenting the inlet into a capillary inlet and a sample slot, the design allows users to choose the safer pipette method through the sample slot when working with collection tubes, reducing direct contact risks. The capillary inlet remains available for situations where direct contact is necessary, maintaining simplicity while improving safety options.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sample slot acts as an intermediary interface that allows pipettes to transfer samples without direct fingertip contact with the microcuvette body. This intermediary mechanism reduces the risk of biohazardous spills and contamination by eliminating the need for fingers to directly touch the sample inlet area.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If only a single sample inlet is provided, then the device structure is simple, but the adaptability deteriorates because it cannot accommodate both direct fingertip loading and pipette injection

Engineering Contradiction:
Improvesample loading methodsVSAvoidinlet structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The inlet structure is segmented into two functional components: the capillary inlet optimized for direct fingertip contact and the sample slot optimized for pipette injection. This segmentation enables the device to adapt to different sample loading methods without requiring a single complicated inlet design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dual-inlet design provides universal compatibility with both capillary sampling and pipette-based sample transfer methods. The capillary inlet handles direct fingertip loading while the sample slot accommodates micropipettes, making the device versatile for various laboratory and field applications.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Measurement precision

If the cavity width is uniform, then the manufacturing precision is easier to achieve, but the measurement precision deteriorates due to air bubble trapping in the detection zone

Engineering Contradiction:
Improveoptical analysis accuracyVSAvoidcavity width tolerance
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The cavity width is designed with local variation: it is wider in the sample loading region to facilitate sample introduction and then gradually narrows toward the detection zone. This local quality change ensures that air bubbles are excluded from the detection area, improving measurement precision without requiring extremely tight manufacturing tolerances across the entire cavity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of maintaining a uniform narrow width throughout the cavity (which would prevent bubble trapping but be difficult to manufacture), the design inverts the approach by having a wider section that transitions to a narrower detection zone. This inversion allows easier manufacturing while still achieving the bubble-exclusion function needed for precise measurements.

Inventive Principle:
Principle #13The other way round (Inversion)

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

Enhances user convenience and measurement accuracy by allowing flexible sample loading from fingertips or collection tubes, reducing the risk of spills and contamination, and enabling variable sample volumes to be loaded efficiently.

Implementation Method 1

A capillary microcuvette includes a body member having two planar plates and a cavity formed within the body member. A capillary inlet is communicated with the cavity at one end of the body member along a longitudinal axis of the body member. The cavity has a width which gradually decreases in a direction from the capillary inlet to a sample slot

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2745779B8Capillary microcuvette having double collection means
Publication Date: 2016.08.31 BODITECHMED INC

AI summary

The present invention relates to a capillary microcuvette, the microcuvette comprises a body member having two plates and a cavity formed within the body, the cavity being defined by two opposing inner surfaces of the two plates of the body member, a portion of the cavity defining a detection zone, a capillary inlet being provided at one end of the body member that is communicated with the cavity, a sample slot being provided at a portion of the body member in which the capillary inlet is not formed, the sample slot being communicated with the cavity. The present microcuvette improves user convenience by providing dual application means of applying a specimen directly from a fingertip or using a pipette.