Engineering of Nucleic Acids and Synthetic Cofactors as Holo Sensors for Probing Signaling Molecules in the Cellular Membrane Microenvironment

DNA-Based Molecular Engineering of the Cell Membrane

The cell membrane serves as a barrier and gatekeeper to regulate the cellular transportation of substances and information. It plays a significant role in protecting the cell from the extracellular environment, maintaining intracellular homeostasis, and regulating cellular function and behaviors. The capability to engineer the cell membrane with functional modules that enable dynamic monitoring and manipulating the cell-surface microenvironment would be critical for studying molecular mechanisms underlying various biological processes. To meet this goal, DNA, with intrinsic advantages of high versatility, programmability, and biocompatibility, has gained intense attention as a molecular tool for cell-surface engineering. The past three decades have witnessed the rapid advances of diverse nucleic acid materials, including functional nucleic acids (FNAs), dynamic DNA circuits, and exquisite DNA nanostructures. In this mini review, we have summarized the recent progress of DNA technology for cell membrane engineering, particularly focused on their applications for molecular sensing and imaging, precise cell identification, receptor activity regulation, and artificial membrane structures. Furthermore, we discussed the challenge and outlook on using nucleic acid materials in this specific research area.

Logic-Gated Proximity Aptasensing for Cell-Surface Real-Time Monitoring of Apoptosis

In nature, intact apoptotic cells release ATP as a signaling molecule to trigger prompt phagocytic clearance, even at the earliest stage of apoptosis. Inspired by this, here we introduce a straightforward strategy for real-time monitoring ATP exocytosis and drug-stimulated apoptosis in the cancer cell surroundings. Triplex-boosted G-quadruplexes (tb-G4s) responding to cell environmental factors (H⁺ and K⁺ ) are engineered to construct a DNA logic-gated nanoplatform for proximity ATP aptasensing on the cell surface. It enables the real-time monitoring of cell apoptosis by capturing released endogenous ATP during chemotherapy drug stimulation, providing a sensitive approach for dynamically evaluating drug-induced apoptosis and therapeutic efficacy.

Synthetic DNA for Cell-Surface Engineering

The cell membrane is not only a physical barrier, but also a functional organelle that regulates the communication between a cell and its environment. The ability to functionalize the cell membrane with synthetic molecules or nanostructures would advance cellular functions beyond what evolution has provided. The aim of this Minireview is to introduce recent progress in using synthetic DNA and DNA-based nanostructures for cell-surface engineering. We first introduce chemical conjugation and physical binding methods for monovalent and polyvalent surface engineering. We then introduce the application of these methods for either the promotion or inhibition of cell-environment communication in numerous applications, including the promotion of cell-cell recognition, regulation of intracellular pathways, protection of therapeutic cells, and sensing of the intracellular and extracellular microenvironments. Lastly, we summarize current challenges existing in this area and potential solutions to solve these challenges.

A Smart, Autocatalytic, DNAzyme Biocircuit for in Vivo, Amplified, MicroRNA Imaging

DNAzymes have been recognized as promising transducing agents for visualizing endogenous biomarkers, but their inefficient intracellular delivery and limited amplification capacity (including insufficient cofactor supply) preclude their extensive biological application. Herein, an autocatalytic DNAzyme (ACD) biocircuit is constructed for amplified microRNA imaging in vivo based on a hybridization chain reaction (HCR) and DNAzyme biocatalysis, sustained by a honeycomb MnO₂ nanosponge (hMNS). The hMNS not only delivers DNA probes, but also supplies Mn²⁺ as a DNAzyme cofactor and magnetic resonance imaging (MRI) agent. Through the subsequent cross-activation of HCR and DNAzyme amplicons, the ACD amplifies the limited signal resulting from miRNA recognition. The hMNS/ACD system was used to image microRNA in vivo, thus demonstrating its great promise in cancer diagnosis.