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Recently, lipid nanoparticles (LNPs) have been extensively investigated as non-viral carriers of nucleic acid vaccines due to their high transport efficiency, safety, and straightforward production and scalability. However, the molecular mechanism underlying the interactions between nucleic acids and phospholipid bilayers within LNPs remains elusive. In this study, we employed the all-atom molecular dynamics simulation to investigate the interactions between single-stranded nucleic acids and a phospholipid bilayer. Our findings revealed that hydrophilic bases, specifically G in single-stranded RNA (ssRNA) and single-stranded DNA (ssDNA), displayed a higher propensity to form hydrogen bonds with phospholipid head groups. Notably, ssRNA exhibited stronger binding energy than ssDNA. Furthermore, divalent ions, particularly Ca2+, facilitated the binding of ssRNA to phospholipids due to their higher binding energy and lower dissociation rate from phospholipids. Overall, our study provides valuable insights into the molecular mechanisms underlying nucleic acid-phospholipid interactions, with potential implications for the nucleic acids in biotherapies, particularly in the context of lipid carriers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adopt the strategy of splitting Cas12a activator to achieve dual target detection. • First combination of cleaved Cas12a activator and three-way junction structure. • The strategy of capturing targets with double binding sites is adopted. • Direct detection of RNA without reverse transcription. • Detection range was 1 pM–10 nM, and the detection limit was 205 fm. We developed a novel CRISPR/Cas12a fluorescence biosensor to specifically detect the H1N1 virus based on splitting single-stranded DNA (ssDNA) activators. Specifically, activators 1 and 2 were generated from dual target nucleic acid sites to induce a three-way junction (3WJ) isothermal amplification process. Two specific H1N1 RNA nucleic acid sites were bound to a set of probes to form a 3WJ, which facilitated repeated extension and nicking reactions to produce high levels of split ssDNA activators via DNA polymerase and nicking endonuclease activity. Amplified activators 1 and 2 fully assembled with Cas12a/crRNA to form complexes. Activated Cas12a trans -cleaved ssDNA reporter molecules to generate fluorescence signals. Under optimal conditions, biosensor dynamic detection range was 1 pM–10 nM, and the detection limit was 205 fM. Thus, our biosensor showed high specificity, reliability, and robustness, which highlights its potential use for H1N1 diagnostics. [ABSTRACT FROM AUTHOR]

Fluorescence biosensor to detect microRNAs via integrating DNA hairpins transition mediated strand displacement amplification with primer exchange reaction. [Display omitted] Herein, we constructed a fluorescence biosensor for the ultra-sensitive analysis of microRNAs (miRNAs) by combining DNA hairpins transition triggered strand displacement amplification (DHT-SDA) with primer exchange reaction (PER). Target miRNA initiated DHT-SDA to facilitate the generation of multiple single-stranded DNA (ssDNA) as PER primer, which was extended into a long ssDNA. The biosensor is successfully utilized in detecting miRNAs with high sensitivity (limit of detection for miRNA-21 was 58 fM) and a good linear relationship between 100 nM and 100 fM. By simply changing the DNA hairpin sequence, the constructed biosensor can be extended to analyze another miRNAs. Moreover, the biosensor has the feasibility of detecting miRNAs in real samples with satisfactory accuracy and reliability. Therefore, the fluorescent biosensor has great application potential in clinical diagnosis. [ABSTRACT FROM AUTHOR]