Although carbon nanotubes (CNTs) are remarkable materials with many exceptional characteristics, their poor chemical functionality limits their potential applications. Herein, a strategy is proposed for functionalizing CNTs, which can be achieved with any functional group (FG) without degrading their intrinsic structure by using a deoxyribonucleic acid (DNA)‐binding peptide (DBP) anchor. By employing a DBP tagged with a certain FG, such as thiol, biotin, and carboxyl acid, it is possible to introduce any FG with a controlled density on DNA‐wrapped CNTs. Additionally, different types of FGs can be introduced on CNTs simultaneously, using DBPs tagged with different FGs. This method can be used to prepare CNT nanocomposites containing different types of nanoparticles (NPs), such as Au NPs, magnetic NPs, and quantum dots. The CNT nanocomposites decorated with these NPs can be used as reusable catalase‐like nanocomposites with exceptional catalytic activities, owing to the synergistic effects of all the components. Additionally, the unique DBP–DNA interaction allows the on‐demand detachment of the NPs attached to the CNT surface; further, it facilitates a CNT chirality‐specific NP attachment and separation using the sequence‐specific programmable characteristics of oligonucleotides. The proposed method provides a novel chemistry platform for constructing new functional CNTs suitable for diverse applications.

We conducted large‐scale screening test on drugs that were already approved for other diseases to find pigmentation‐modulating agents. Among drugs with potential for pigmentation control, we selected sorafenib and further investigated the effect on pigmentation using HM3KO melanoma cells. As a result of treating melanoma cells with sorafenib, pigmentation was promoted in terms of melanin content and tyrosinase activity. Sorafenib increased mRNA and protein levels of pigmentation‐related genes such as MITF, tyrosinase and TRP1. To uncover the action mechanism, we investigated the effect of sorafenib on the intracellular signalling pathways. Sorafenib reduced phosphorylation of AKT and ERK, suggesting that sorafenib induces pigmentation through inhibition of the AKT and ERK pathways. In addition, sorafenib significantly increased the level of active β‐catenin, together with activation of β‐catenin signalling. Mechanistic study revealed that sorafenib decreased phosphorylation of serine 9 (S9) of GSK3β, while it increased phosphorylation of tyrosine 216 (Y216) of GSK3β. These results suggest that sorafenib activates the β‐catenin signalling through the regulation of GSK3β phosphorylation, thereby affecting the pigmentation process.

Systematic evolution of ligands by exponential enrichment (SELEX) is a method that is generally used for developing aptamers, which have arisen the promising alternatives for antibodies. However, conventional SELEX methods have limitations, such as a limited selection of target molecules, time-consuming and complex fabrication processes, and labor-intensive processes, which result in low selection yields. Here, we used (i) graphene oxide (GO)-coated magnetic nanoparticles in the selection process for separation and label-free detection and (ii) a multilayered microfluidic device manufactured using a three-dimensionally printed mold that is equipped with automated control valves to achieve precise fluid flows. The developed on-chip aptamer selection device and GO-coated magnetic nanoparticles were used to screen aptamer candidates for adenosine in eight cycles of the selection process within approximately 2 h for each cycle. Based on results from isothermal titration calorimetry, an aptamer with a dissociation constant of 18.6 ± 1.5  μM was selected. Therefore, the on-chip platform based on GO-coated magnetic nanoparticles provides a novel label-free screening technology for biosensors and micro/nanobiotechnology for achieving high-quality aptamers.