Target-catalyzed self-assembled spherical G-quadruplex/hemin DNAzymes for highly sensitive colorimetric detection of microRNA in serum.

The accurate and visual detection of circulating microRNA (miRNA) has attracted increasing interest due to its pivotal role in clinical disease diagnosis. Taking advantages of nucleic acid isothermal amplification and enzyme-catalyzed chromogenic reaction, here, a colorimetric sensing strategy was proposed for sensitive miRNA analysis. When the target miRNA was present, local catalytic hairpin assembly (CHA) would be triggered and proceed continuously to form dozens of double-stranded oligonucleotides with G-rich sticky ends on the gold nanoparticle, which could self-assemble into a spherical G-quadruplex (GQ)/hemin DNAzyme by binding with hemin and potassium ions. As a horseradish peroxidase-mimic, GQ/hemin DNAzyme could catalyze the redox reaction and color change of the substrates. Taking miRNA-21 as an example, the developed method exhibited satisfactory specificity as well as high sensitivity with a detection limit of 90.3 fM. Furthermore, the sensing platform has been successfully employed to detect miRNA-21 in spiked serum, providing a promising tool for early diagnosis of cancers.

Patterned Duplex Fabric Based on Genetically Modified Spidroin for Smart Wound Management.

The treatment of diabetic wounds remains a great challenge for the medical community. Here, a smart patterned DNA double helix (duplex)-like fabric based on genetically modified spider silk protein (PDF-S) which is inspired by soft plant tendrils, is proposed for diabetic wound treatment. Benefiting from spider silk protein (spidroin); PDF-S is equipped with high strength; high toughness, and excellent biocompatibility. Notably, the fabric crimped through the biomimetic DNA double-helix-like structure can effectively adapt to tensile impact and the maximum stretch rate reaches 1500%. A pattern-based microfluidic channel of PDF-S allowed wound secretion to flow spontaneously through the channel. Meanwhile; due to the optical properties of the introduced photonic crystal structure; PDF-S is equipped with fluorescence enhancement properties; enabling PDF-S to display color-sensitive behavior suitable for wound monitoring and guiding clinical treatment. In addition, to enable sensitive motion monitoring, microelectronic circuits are integrated on the surface of the PDF-S. These unique material features suggest that this study will lead to a new generation of biomimetic artificial spider silk materials for design and application in the biomedical field.