ABSTRACT
Membrane curvature reflects physical forces operating on the lipid membrane, which plays important roles in cellular processes. Here, we design a mechanosensitive DNA (MSD) nanomachine that mimics natural mechanosensitive PIEZO channels to convert the membrane tension changes of lipid vesicles with different sizes into fluorescence signals in real time. The MSD nanomachine consists of an archetypical six-helix-bundle DNA nanopore, cholesterol-based membrane anchors, and a solvatochromic fluorophore, spiropyran (SP). We find that the DNA nanopore effectively amplifies subtle variations of the membrane tension, which effectively induces the isomerization of weakly emissive SP into highly emissive merocyanine isomers for visualizing membrane tension changes. By measuring the membrane tension via the fluorescence of MSD nanomachine, we establish the correlation between the membrane tension and the curvature that follows the Young-Laplace equation. This DNA nanotechnology-enabled strategy opens new routes to studying membrane mechanics in physiological and pathological settings.
Subject(s)
Nanopores , Nanotechnology , Fluorescence , DNA , Lipids , Cell MembraneABSTRACT
Herein we utilized the thermal hysteresis method to directly probe the self-assembly process of amphiphilic DNA nanostructures, with the use of an amphiphilic tetrahedral DNA framework (am-TDF) as a model system. The analysis of the reaction rate surfaces under different ionic strengths revealed that strands of amphiphilic DNA first formed metastable micelles via an entropy-driven process, which were then enthalpically transformed into am-TDF.
Subject(s)
Micelles , Nanostructures , DNA/chemistry , Entropy , Nanostructures/chemistryABSTRACT
Herein we examined the utilization of the orthogonal noncovalent interaction to program the self-assembly of amphiphilic DNA frameworks (am-FNAs). By finely controlling reaction parameters such as ionic strength, the length of amphiphilic DNA, and mechanical agitation, we constructed a series of amphiphilic DNA-based primary logic gates (NOT, AND, OR and INH) and a secondary logic gate (NOT-OR).
Subject(s)
DNA , LogicABSTRACT
Synthetic molecular machines have received increasing attention because of their great ability to mimic natural biological motors and create novel modes of motion. However, very few examples have been implemented with real autonomous movement inside living cells, due to the challenges of the driving force and highly integrated system design. In this work, we report an elegant, highly integrated DNA nanomachine that can be powered by endogenous ATP molecules and autonomously operated inside living cells without any auxiliary additives. It assembles all components on a single gold nanoparticle (AuNP) including a hairpin-locked swing arm encoding a start triggered by an intracellular target molecule and a two-stranded DNA track responding to the motion of the swing arm. When the intracellular target activates the nanomachine via the unlocking swing arm, the machine autonomously and progressively operates on the established DNA track via intramolecular toehold-mediated strand migration and internal ATP binding. This paper also demonstrates the machine's bioanalytical application for specific microRNA (miRNA) imaging in living cells.
ABSTRACT
We rationally engineered an elegant entropy-driven DNA nanomachine with three-dimensional track and applied it for intracellular miRNAs imaging. The proposed nanomachine is activated by target miRNA binding to drive a walking leg tethered to gold nanoparticle with a high density of DNA substrates. The autonomous and progressive walk on the DNA track via the entropy-driven catalytic reaction of intramolecular toehold-mediated strand migration leads to continuous disassembly of DNA substrates, accompanied by the recovery of fluorescence signal due to the specific release of a dye-labeled substrate from DNA track. Our nanomachine outperforms the conventional intermolecular reaction-based gold nanoparticle design in the context of an improved sensitivity and kinetics, attributed to the enhanced local effective concentrations of working DNA components from the proximity-induced intramolecular reaction. Moreover, the nanomachine was applied for miRNA imaging inside living cells.
