Patterned Capillary Device for Signal-to-Noise Ratio
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Solution Overview
Problem
Classical flow cytometry techniques face challenges in achieving high sensitivity and signal-to-noise ratios when detecting fluorescent particles due to high excitation power densities and the need for precise optical alignment, which limits their effectiveness in detecting small particles with short transit times through capillary devices.
Innovation Solution
A patterned capillary device is fabricated with an opaque gold film on its inner surface, featuring transparent and opaque segments that adhere to specific areas, allowing only fluorescence emitted during the particle's transit through transparent segments to be detected, enhancing signal discrimination and reducing background noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a highly focused excitation beam is used to probe a small volume inside a capillary, then the signal-to-noise ratio is improved, but the device complexity and precision optical alignment requirements increase
Solution Approach 1:
The patent replaces the mechanical/optical alignment system with a photomask-based spatial encoding system. Instead of using precision optics to focus excitation light, the system uses a photomask to define transmission patterns that encode spatial information directly into the detected signal, eliminating the need for precise optical alignment while maintaining measurement precision
Solution Approach 2:
The patent creates a spatial copy of the encoding pattern on the capillary surface that can be read optically without requiring precise focus. The photomask pattern is transferred to the capillary wall, creating a static spatial code that can be detected by simple transmission measurements, copying the information encoding function from a complex optical system to a simple patterned surface
2Measurement precision
If the gold film pattern is left exposed on the inner surface, then the initial signal discrimination is achieved, but the pattern lifespan is reduced due to physical wear
Solution Approach 1:
The patent applies a protective coating over the gold film pattern before the capillary is put into service. This preliminary protective action prevents physical wear and damage to the pattern during particle flow, extending the pattern lifespan while preserving the signal discrimination capability of the underlying gold film structure
Solution Approach 2:
The patent uses a thin protective film or coating layer that conforms to the capillary's inner surface geometry. This thin film protects the rigid gold film pattern from mechanical damage caused by flowing particles while allowing optical transmission for detection, demonstrating the principle of using flexible protective layers to shield fragile structures
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 patterned capillary device improves signal-to-noise ratios and extends the lifespan of the detection pattern by protecting the gold film from physical wear, enabling more accurate and durable detection of fluorescent particles with reduced scattering and improved multiplex detection capabilities.
Implementation Method 1
flowing a solution comprising gold seeds though the capillary, the seeds adhering to non-exposed segments of the inner surface
Implementation Method 2
a substantially opaque film covering the inner surface of the wall, the opaque film comprising a plurality of substantially transparent segments defining a pattern
Implementation Method 3
the response of classical flow cytometers decrease as a function of emitter size... high luminosity, photostability
Data Source
AI summary
A patterned capillary device comprising a pattern on an inner surface is described herein. More specifically, the patterned capillary device comprises a wall having an outer surface and an inner surface, the wall defining a fluidic channel. A substantially opaque film covers the inner surface of the wall, the opaque film comprising a plurality of substantially transparent segments defining a pattern. A process for fabricating a pattern formed of opaque and transparent portions on an inner surface of a capillary device is also described herein.