In this communication, we fabricated graphene oxide membranes with tunable permeation by embedding carbon nanodots of controllable sizes.

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We report a new method for the detection of regional DNA methylation using basedependent affinity interaction (i.e., adsoption) of DNA with graphene. Due to the strongest adsorption affinity of guanine bases towards graphene, bisulfite-treated guanine-enriched methylated DNA leads to a larger amount of the adsorbed DNA on the graphene-modified 2 electrodes in comparison to the adenine-enriched unmethylated DNA. The level of the methylation is quantified by monitoring the differential pulse voltammetric current as a function of the adsorbed DNA. The assay is sensitive to distinguish methylated and unmethylated DNA sequences at single CpG resolution by differentiating changes in DNA methylation as low as 5%. Furthermore, this method has been used to detect methylation levels in a collection of DNA samples taken from oesophageal cancer tissues.

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Low‐cost flexible organic light‐emitting diodes (OLEDs) with nanoemitter material from waste open up new opportunities for sustainable technology. The common emitter materials generated from waste are carbon dots (CDs). However, these have poor luminescent properties. Further solid‐state emission quenching makes application in display devices challenging. Here, flexible and rigid OLED devices are demonstrated using self‐assembled 2D arrays of CDs derived from waste material, viz., human hair. High‐performance CDs with a quantum yield (QY) of 87%, self‐assembled into 2D arrays, are achieved by improving the crystallinity and decreasing the CDs' size distribution. The CD island array exhibits ultrahigh hole mobility (≈10−1 cm2 V−1 s−1) and significant reduction in solid‐state emission quenching compared to pristine CDs; hence, it is used here as an emitting layer in both indium tin oxide (ITO)‐coated glass and ITO‐coated flexible poly(ethylene terephthalate) (PET) substrate OLED devices, without any hole‐injection layer. The flexible OLED device exhibits a stable, voltage‐independent blue/cyan emission with a record maximum luminescence of 350 cd m−2, whereas the OLED device based on the rigid glass substrate shows a maximum luminescence of 700 cd m−2. This work sets up a platform to develop next‐generation OLED displays using CD emitters derived from the biowaste material.