Surface Acoustic Wave Nebulization for Narrow Lung-Delivery Droplets
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Solution Overview
Problem
Current nebulizer systems have limitations in delivering drugs to the lungs, with only 70%-80% of the dose reaching the lung tissue, and are unable to effectively nebulize suspensions and liquids with high viscosity and surface tension, while also producing broad droplet size distributions that are suboptimal for respiratory disease treatment.
Innovation Solution
A device using surface acoustic waves (SAWs) to generate nebulized droplets by interacting with a liquid in an array of cavities on a SAW transmission surface, providing controlled droplet size distribution and improved delivery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional nebulizer systems are used, then the device complexity is low and ease of manufacture is high, but the delivery efficiency to lungs is only 70%-80% and droplet size distribution is broad
Solution Approach 1:
The device segments the liquid into discrete droplets using an array of cavities, where each cavity acts as an independent nebulization unit. This segmentation approach enables precise control over droplet formation and size distribution, improving delivery efficiency to 95% or more of the dose reaching the lungs.
Solution Approach 2:
The patent replaces conventional mechanical nebulization systems with surface acoustic wave (SAW) technology. The SAW transducer generates acoustic waves that interact with the liquid in cavities to produce monodisperse droplets, substituting mechanical disruption with acoustic field control, thereby achieving narrow droplet size distribution while maintaining device simplicity.
2Manufacturing precision
If ultrasonic nebulizers are used to generate fine droplets, then droplet size can be reduced, but the system cannot effectively nebulize suspensions and liquids with high viscosity and surface tension
Solution Approach 1:
The device changes the nebulization mechanism from ultrasonic vibration to surface acoustic wave interaction, which fundamentally alters how liquid is disrupted. SAWs propagate along the cavity surfaces and create controlled rupture points, allowing effective nebulization of suspensions and high-viscosity liquids that cannot be processed by conventional ultrasonic nebulizers.
Solution Approach 2:
The array of cavities acts as an intermediary structure between the SAW transducer and the liquid. The cavities concentrate and guide the acoustic energy to specific locations on the liquid surface, enabling controlled droplet formation from various liquid types including suspensions and high-viscosity formulations.
3Adaptability or versatility
If broad droplet size distribution is produced, then the device can handle various liquid viscosities, but the therapeutic effectiveness is reduced due to droplets being trapped in upper respiratory tract or throat
Solution Approach 1:
The device implements local quality control by creating uniform droplet sizes at each cavity location through SAW interaction. Each cavity produces droplets with consistent size characteristics, and the array of cavities collectively generates a monodisperse aerosol distribution, ensuring all droplets are within the optimal 1-5 μm range for deep lung penetration.
Solution Approach 2:
The patent uses surface acoustic waves—a form of mechanical vibration propagating along the cavity surfaces—to control droplet formation. By tuning the SAW frequency and utilizing the resonant interaction with liquid in cavities, the system produces consistent droplet sizes that optimize lung delivery while maintaining the ability to handle various liquid formulations.
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 achieves greater than 95% delivery of active drug to the lungs, enhancing treatment outcomes for respiratory diseases by producing droplets with a narrow size distribution within the 1-5 μm range, optimal for lung penetration.
Implementation Method 1
a surface acoustic wave (SAW) transducer adapted to generate and propagate SAWs along the SAW transmission surface, wherein, in operation, SAWs propagating along the SAW transmission surface interact with the liquid in the cavities to produce nebulised droplets of the liquid
Data Source
AI summary
A device is disclosed for the preparation of nebulised droplets, for inhalation. The device has: a surface acoustic wave (SAW) transmission surface; a SAW transducer adapted to generate and propagate SAWs along the SAW transmission surface; and an array of cavities opening at the SAW transmission surface for containing a liquid. In operation, SAWs propagating along the SAW transmission surface interact with the liquid in the cavities to produce nebulised droplets of the liquid. Operation of the device results in a nebulised plume of droplets of average diameter in the range 1-5 μm.