Rolling circle amplification (RCA) is an isothermal enzymatic process where a short DNA or RNA primer is amplified to form a long single stranded DNA or RNA using a circular DNA template and special DNA or RNA polymerases. The RCA product is a concatemer containing tens to hundreds of tandem repeats that are complementary to the circular template. The power, simplicity, and versatility of the DNA amplification technique have made it an attractive tool for biomedical research and nanobiotechnology. Traditionally, RCA has been used to develop sensitive diagnostic methods for a variety of targets including nucleic acids (DNA, RNA), small molecules, proteins, and cells. RCA has also attracted significant attention in the field of nanotechnology and nanobiotechnology. The RCA-produced long, single-stranded DNA with repeating units has been used as template for the periodic assembly of nanospecies. Moreover, since RCA products can be tailor-designed by manipulating the circular template, RCA has been employed to generate complex DNA nanostructures such as DNA origami, nanotubes, nanoribbons and DNA based metamaterials. These functional RCA based nanotechnologies have been utilized for biodetection, drug delivery, designing bioelectronic circuits and bioseparation. In this review, we introduce the fundamental engineering principles used to design RCA nanotechnologies, discuss recently developed RCA-based diagnostics and bioanalytical tools, and summarize the use of RCA to construct multivalent molecular scaffolds and nanostructures for applications in biology, diagnostics and therapeutics.

A comprehensive review that offers mechanistic insight into the CRISPR–Cas toolbox for analytical and diagnostic assay development.

Dynamic DNA assemblies, including catalytic DNA circuits, DNA nanomachines, molecular translators, and reconfigurable nanostructures, have shown promising potential to regulate cell functions, deliver therapeutic reagents, and amplify detection signals for molecular diagnostics and imaging. However, such applications of dynamic DNA assembly systems have been limited to nucleic acids and a few small molecules, due to the limited approaches to trigger the DNA assemblies. Herein, we describe a binding-induced DNA strand displacement strategy that can convert protein binding to the release of a predesigned output DNA at room temperature with high conversion efficiency and low background. This strategy allows us to construct dynamic DNA assembly systems that are able to respond to specific protein binding, opening an opportunity to initiate dynamic DNA assembly by proteins.