Figure 5.

Novel strategies for integrated detection and quantitation of ctDNA. (a) Schematic of self-powered bidirectional partition microfluidic chip with embedded microwells. A layered microfluidic chip was designed such that the sample was loaded into the chip through the inlet and distributed into microwells in two directions. The microchannels connected to the red channel are alternatively embedded in the row of microwells linked to the channel. The embedded microwells allow decreasing of the blank area on the chip without shortening the interval of alternate microwells. The blue line around the array denotes the hydration channel. Reproduced with permission from Geng et al. ²⁷⁶ under open Creative Commons Attribution License. (b) Integrated biochip equipped with central lysis and four amplification/detection chambers linked by the fluidic channels for targeted ctDNA analysis. The on-chip electrical cell lysis releases cellular targets and the nanofluidic manipulations are under an AC field to enhance isothermal solid phase amplification. Superparamagnetic iron oxide particle nanozyme-mediated redox reaction allows for electrochemical detection of surface-immobilized amplicons. Reproduced with permission from Koo et al. ²⁸⁰ Copyright 2020 American Chemical Society. (c) Schematic illustration of the pump-free, high-throughput microfluidic chip-based SERS assay for ctDNA detection. The chip was developed with Cu2O octahedra and an AuNB array as the SERS-active substrate and CHA-HCR as the dual amplification strategy. Reproduced with permission from Cao et al. ²⁸⁴ under open Creative Commons Attribution License.