The multivalent effect is often used to engineer microfluidic affinity interfaces to improve the target separation efficiency. Currently, no design rules exist for thermodynamic and kinetic tuning of properly joining multiple ligands. Herein, we developed a thermodynamic and kinetic modulating strategy of the microfluidic affinity interface via a merit-complementary-heteromultivalent aptamers functionalized DNA nanoassembly. Our strategy is built on the two types of identified aptamers that bind to distinct sites of EpCAM. The aptamer binding of one type is more rapid but less tight, while the other is opposite. By assembling the two types of aptamers together with a tetrahedral DNA framework, we fully exploited these aptamers' merits for tight and rapid recognition of EpCAM, leading to target cell capture with high efficiency and throughput. Our strategy provides a perspective on engineering multivalent recognition molecules through thermodynamic and kinetic tuning.

The blood-brain barrier (BBB) controls chemical access to the brain and maintains fluid homeostasis, but in vitro models accurately simulating the physiological characteristics of the BBB are lacking. Here, we...

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Adeno-associated virus (AAV) is a versatile gene vector that is widely used in mammalian research. In basic studies and large-scale AAV production, genetic testing is ubiquitous and routine polymerase chain reaction (PCR)-based tests limit the efficiency due to the labor-intensive and time-consuming requirements of thermal cycling. This study introduces an assay based on recombinase-aided amplification combined with lateral flow (LF-RAA), which can quickly and accurately detect the AAV genome, thus improving the efficiency of AAV research and production. This application is the first use of an RAA approach to AAV genome detection. In this point-of-care testing (POCT) detection platform, the RAA reaction and LF readout are integrated into a user-friendly microfluidic chip that can be applied without advanced technical training. The LF-RAA chip provides high sensitivity, with a limit of detection of 10 copies/μL, and generates results quickly, and it only needs to be incubated for 10 min at a constant temperature, that is, 39 °C. Results are visualized on the LF Dipstick, and detection results are reliable, validated with 100% accuracy in 47 laboratory-produced recombination adeno-associated virus (rAAV) samples carrying target genes from several different viruses. The LF-RAA assay is applicable in AAV research and production processes requiring genome identification.