Metabolic labeling experiments followed by immunoprecipitation were performed to investigate the kinetics, location and inhibitor sensitivity of degradation of both wild‐type (wt) and mutant (delta F508) cystic fibrosis conductance transmembrane regulator (CFTR). At the earliest stages of the biosynthetic process, both wt and delta F508 CFTR were found to be susceptible to degradation by endogenous proteases. Virtually all delta F508 CFTR and 45‐80% of wt CFTR were rapidly degraded with a similar half‐life (t1/2 approximately 0.5 h). The remaining wt CFTR attained a protease‐resistant configuration regardless of whether traffic between the endoplasmic reticulum (ER) and Golgi was operational. Metabolic energy is required for the conformational transition, but not to maintain the stability of the protease‐resistant wt CFTR. Intracellular degradation of delta F508 CFTR and of incompletely folded wt CFTR occurs in a non‐lysosomal, pre‐Golgi compartment, as indicated by the sensitivity of proteolysis to different inhibitors and temperature. Accordingly, products of the degradation of delta F508 CFTR could be detected by immunoblotting in isolated ER, but not in the Golgi. Together, these results suggest a dynamic equilibrium between two forms of wt CFTR in the ER: an incompletely folded, protease‐sensitive form which is partially converted by an ATP‐dependent process to a more mature form that is protease‐resistant and capable of leaving the ER. The inability delta F508 CFTR to undergo such a transition renders it susceptible to complete and rapid degradation in a pre‐Golgi compartment.

The ability to accurately identify and isolate cells is the cornerstone of precise disease diagnosis and therapies. A single-step cell identification method based on logic analysis of multiple surface markers will have unique advantages because of its accuracy and efficacy. Herein, using multiple DNA aptamers for cancer biomarker recognition and associative toehold activation for signal integration and amplification as two molecular keys, we have successfully operated a cell-surface device that can perform AND Boolean logic analysis of multiple biomarkers and precisely label the target cell subtype in large populations of similar cells via the presence or absence of different biomarkers. Our approach can achieve single-step cancer cell identification and isolation with excellent sensitivity and accuracy and thus will have broad applications in biological science, biomedical engineering, and personalized medicine.

DNA nanotechnology has been proven to be a powerful platform to assist the development of imaging probes for biomedical research. The attractive features of DNA nanostructures, such as nanometer precision, controllable size, programmable functions, and biocompatibility, have enabled researchers to design and customize DNA nanoprobes for bioimaging applications. However, DNA probes with low molecular weights (e.g., 10–100 nt) generally suffer from low stability in physiological buffer environments. To improve the stability of DNA nanoprobes in such environments, DNA nanostructures can be designed with relatively larger sizes and defined shapes. In addition, the established modification methods for DNA nanostructures are also essential in enhancing their properties and performances in a physiological environment. In this review, we begin with a brief recap of the development of DNA nanostructures including DNA tiles, DNA origami, and multifunctional DNA nanostructures with modifications. Then we highlight the recent advances of DNA nanostructures for bioimaging, emphasizing the latest developments in probe modifications and DNA-PAINT imaging. Multiple imaging modules for intracellular biomolecular imaging and cell membrane biomarkers recognition are also summarized. In the end, we discuss the advantages and challenges of applying DNA nanostructures in bioimaging research and speculate on its future developments.

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