Microfluidic platforms for optical biosensing
Inventors
Assignees
University of South Florida • University of South Florida St Petersburg
Publication Number
US-9687847-B1
Publication Date
2017-06-27
Expiration Date
2034-02-14
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Abstract
In one embodiment, a microfluidic platform for optical biosensing, the platform including an optical substrate, a layer provided on the substrate, and a channel formed within the layer through which fluid can flow, the channel including a constriction that is adapted to trap a microsphere suspended in the fluid when the fluid flows through the channel.
Core Innovation
The invention relates to a microfluidic platform designed for optical biosensing, which comprises an optical substrate, a top layer provided on the substrate, and a channel formed within the layer through which fluid can flow. The channel incorporates a constriction specifically adapted to trap a microsphere, which is suspended in the fluid, at a designated position as the fluid passes through. This precise positioning enables effective optical biosensing using the trapped microsphere as an optical resonator.
The background identifies challenges with existing microsphere resonator biosensors, specifically the difficulty in handling and accurately positioning microspheres due to their small size and the high precision required. Previous solutions involved either mechanical manipulation with micro-positioners, which is challenging, or permanently bonding microspheres to a substrate, which is irreversible and inflexible. The disclosed invention addresses the need for an improved method to handle and position microspheres easily and reversibly for optical biosensing applications.
The platform's constriction is engineered to create a three-point contact with the microsphere (two contact edges and the substrate), holding the microsphere securely in place for analysis while minimizing contact with the optical mode region to preserve resonance quality. The design supports both trap-and-release functionality, allowing for reuse and disposability of microspheres, and enables high sensitivity in detection due to optimal optical coupling and robust microsphere positioning.
Claims Coverage
There are two independent claims, each defining inventive features related to microfluidic platforms for optical biosensing with specific channel constriction geometries and microsphere trapping capabilities.
Microfluidic platform with inverted T-shaped constriction for microsphere trapping
The microfluidic platform comprises: - An optical substrate. - A layer provided on the substrate. - A channel formed within the layer and defined by the layer and substrate, through which fluid can flow. - A constriction in the channel that narrows along the channel's length to a point physically sized to trap a microsphere suspended in the fluid. - The constriction includes two opposed inwardly-extending members that narrow a top portion of the channel. - The inwardly-extending members are defined by lower surfaces (horizontal) and upper surfaces (vertical) forming opposing 90-degree edges, which contact opposite sides of the microsphere.
Microfluidic platform with triangular cross-section constriction for microsphere trapping
The microfluidic platform comprises: - An optical substrate. - A layer provided on the substrate. - A channel formed within the layer and defined by the layer and substrate, through which fluid can flow. - A constriction in the channel that narrows along the channel's length to a point physically sized to trap a microsphere suspended in the fluid. - The constriction features two opposed inwardly-extending members which are opposing walls angled toward each other, forming a constriction with a triangular cross-section.
The patent claims cover microfluidic platforms for optical biosensing with specific channel constriction geometries—including inverted T-shaped and triangular cross-sections—that are physically configured to trap microspheres, facilitating their use in optical biosensing.
Stated Advantages
Enables easy and reversible handling and positioning of microspheres for optical biosensing.
Eliminates the need for optical alignment by the end user and removes the requirement for surface regeneration of the optical resonator.
Allows use of low-cost and disposable microspheres in a reusable microfluidic cell.
Maintains the quality (Q-factor) of optical resonances by minimizing overlap between contact points and the excited optical mode region of the microsphere.
Provides robust trap-and-release functionality, enabling secure trapping and easy removal of microspheres.
Documented Applications
Analysis of biomolecular interactions for drug discovery.
Detection of bacteria and viruses for medical diagnosis.
Environmental monitoring.
Homeland security applications involving detection of specific biomolecules.
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