Cell-free DNA (cfDNA), which promotes precision oncology, has received extensive concern because of its abilities to inform genomic mutations, tumor burden and drug resistance. The absolute quantification of cfDNA concentration has been proved as an independent prognostic biomarker of overall survival. However, the properties of low abundance and high fragmentation hinder the isolation and further analysis of cfDNA. Microfluidic technologies and lab-on-a-chip (LOC) devices provide an opportunity to deal with cfDNA sample at a micrometer scale, which reduces required sample volume and makes rapid isolation possible. Microfluidic platform also allow for high degree of automation and high-throughput screening without liquid transfer, where rapid and precise examination and quantification could be performed at the same time. Microfluidic technologies applied in cfDNA isolation and analysis are limited and remains to be further explored. This paper reviewed the existing and potential applications of microfluidic technologies in collection and enrichment of cfDNA, quantification, mutation detection and sequencing library construction, followed by discussion of future perspectives.

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Freestanding graphene films are desired to be widely applied in biosensor fabrication due to their distinctive physical properties and improved performance. Chemical vapor deposition has been developed to efficiently fabricate large-area graphene. However, some of the fabricated graphene films might break or be contaminated in the current transferring step using polymers. A stable and high-quality transfer method is needed. Herein, we report on an advanced transfer method of large-area graphene film which uses fullerene as a supporting substrate. Unlike polymers, which are commonly eliminated by being dissolved in an organic solution, fullerene can be easily removed by evaporation in a vacuum because it has a different heat stability to graphene. By using the improved transferring method, the percentage of integrated freestanding films after transferring was increased from 60.7% to 93.4%. The vacuum is beneficial in terms of keeping the brittle freestanding films intact. Graphene films transferred using fullerene showed an advanced flatness and a simplicial elementary composition in comparison to those transferred using polymers. Even through there is trace residue, this stable allotrope of graphene is considered to have almost no impact on biomolecule sensing. These advantages make the fullerene transferring method an attractive candidate for fabricating large-area freestanding graphene films, especially for using in the field of biochemistry analysis and biosensors.

BackgroundThe extremely small amount of DNA in a cell makes it difficult to study the whole genome of single cells, so whole‐genome amplification (WGA) is necessary to increase the DNA amount and enable downstream analyses. Multiple displacement amplification (MDA) is the most widely used WGA technique.ResultsCompared with amplification methods based on PCR and other methods, MDA renders high‐quality DNA products and better genome coverage by using phi29 DNA polymerase. Moreover, recently developed advanced MDA technologies such as microreactor MDA, emulsion MDA, and micro‐channel MDA have improved amplification uniformity. Additionally, the development of other novel methods such as TruePrime WGA allows for amplification without primers.ConclusionHere, we reviewed a selection of recently developed MDA methods, their advantages over other WGA methods, and improved MDA‐based technologies, followed by a discussion of future perspectives. With the continuous development of MDA and the successive update of detection technologies, MDA will be applied in increasingly more fields and provide a solid foundation for scientific research.

This work proposes a novel method for the semi-quantitative determination of hydrogen peroxide (H2O2) in routine and on-site applications.