This paper describes a strategy for autonomous diagnoses of cancers using microRNA (miRNA) and therapy for tumor cells by DNA computing techniques and nanopore measurement. Theranostics, which involves the combination of diagnosis and therapy, has emerged as an approach for personalized medicine or point-of-care cancer diagnostics. DNA computing will become a potent tool for theranostics because it functions completely autonomously without the need for external regulations. However, conventional theranostics using DNA computing involves a one-to-one reaction in which a single input molecule generates a single output molecule; the concentration of the antisense drug is insufficient for the therapy in this type of reaction. Herein we developed an amplification system involving an isothermal reaction in which a large amount of the antisense DNA drug was autonomously generated after detecting miRNA from small cell lung cancer. In addition, we successfully quantified the amount of the generated drug molecule by nanopore measurement with high accuracy, which was more accurate than conventional gel electrophoresis. This autonomous amplification strategy is a potent candidate for a broad range of theranostics using DNA computing.

Although DNA computation has traditionally been developed for parallel calculations in molecular analyses, this approach has recently been considered for use in diagnostic or medical applications in living systems. In this study, we propose that the DNA logic operation may be a powerful tool for the recognition of microRNA patterns, which may have applications for the early diagnosis of cancers. We developed a rapid, label-free decoding method for output diagnostic molecules using nanopore measurements. We designed diagnostic DNAs that autonomously recognized two microRNAs, miR-20a and miR-17-5p, and formed a four-way junction structure that was captured in the nanopore, showing long blocking currents. We analyzed the blocking duration based on the central limit theorem and found that four different operations, i.e., (0, 0), (0, 1), (1, 0), and (1, 1), could be discriminated. This pattern recognition method has been differentiated from simple detection methods based on DNA computing and nanopore technologies.

One of the greatest challenges faced by chemists and biologists is the detection of molecules at extremely low concentrations. This paper describes a method to detect ultra-low concentrations (1 femtomole) of nucleotides using isothermal amplification and a biological nanopore.

This paper describes a method for detecting microRNA (miRNA) expression patterns using the nanopore-based DNA computing technology. miRNAs have shown promise as markers for cancer diagnosis due to their cancer type specificity, and therefore simple strategies for miRNA pattern recognition are required. We propose a system for pattern recognition of five types of miRNAs overexpressed in bile duct cancer (BDC). The information of miRNAs from BDC is encoded in diagnostic DNAs (dgDNAs) and decoded electrically by nanopore analysis. With this system, we succeeded in the label-free detection of miRNA expression patterns from the plasma of BDC patients. Moreover, our dgDNA–miRNA complexes can be detected at subfemtomolar concentrations, which is a significant improvement compared to previously reported limits of detection (∼10 –12 M) for similar analytical platforms. Nanopore decoding of dgDNA-encoded information represents a promising tool for simple and early cancer diagnosis.

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