Microfluidic Chip Surface Modification for Bacteria Detection

The patent combines multiple functions (sample processing, nucleic acid extraction, amplification, and detection) into a single microfluidic chip system. The chip integrates reaction chambers, fluid channels, and detection zones to perform entire detection workflow in one device, eliminating time-consuming transfer steps between separate equipment while maintaining high sensitivity through localized signal amplification.

The patent replaces complex mechanical sample processing equipment with microfluidic-based automated handling. The microfluidic chip uses integrated fluidic networks and micro-pumps to automate sample preparation and reagent delivery, reducing manual operation time while preserving detection sensitivity through precise control of reaction conditions.

The patent introduces optical detection as an intermediary method between the microfluidic chip and the user. Instead of requiring users to directly interpret complex electrochemical or impedance signals, the system converts bacterial detection into visual color changes or fluorescent signals that can be observed with simple optical equipment, greatly simplifying operation while maintaining high sensitivity through signal amplification mechanisms.

The patent employs colorimetric or fluorescent indicators that change color or emit light in response to bacterial presence. This visual signal transduction allows users to detect bacteria through simple color observation or basic optical detection, eliminating the need for complex electrochemical measurement equipment and specialized operational knowledge.

The patent performs preliminary modification of the microfluidic chip surface before sample introduction. The chip is pre-coated with capture probes or functionalized materials that specifically bind target bacteria, preventing non-specific adsorption of food matrix components. This preliminary functionalization simplifies subsequent optical detection by eliminating the need for complex real-time modification procedures.

The patent applies different functional modifications to different regions of the microfluidic chip. The detection zone is specifically functionalized with capture probes or fluorescent labels, while other regions maintain different surface properties to prevent non-specific binding. This localized functionalization reduces overall modification complexity by focusing complex chemistry only where needed for detection.

The patent transitions from two-dimensional single-layer aptamer surfaces to three-dimensional hierarchical structures. Dendritic polymers provide a branched, three-dimensional framework that extends into the sample volume, creating multiple capture zones at different heights and orientations. This dimensional expansion allows aptamers to effectively contact large bacterial targets from multiple angles, dramatically improving capture efficiency while maintaining structural organization.

The patent implements a nested hierarchical structure where aptamers are attached to dendritic polymers, which are in turn attached to the chip surface. This nested arrangement creates multiple levels of capture sites, with inner layers providing specific binding and outer layers increasing accessibility. The nested structure maximizes capture efficiency by providing both high local concentration of aptamers and extended spatial reach for bacterial contact.