Proximity Ligation Induced DNAzyme Motor Cooperating with Exponential Amplification Reaction for Accurate Low-Density Lipoprotein (LDL) Detection.

Low-density lipoprotein (LDL) is intricately associated with numerous clinical conditions, including dyslipidemia and metabolic-associated fatty liver disease (MAFLD), and its serum concentration is crucial for diagnostic purposes. However, the sensitive and accurate analysis of "intact" LDL is a significant difficulty, as conventional approaches typically focus solely on the detection of cholesterol or surface proteins of LDL. We developed a proximity ligation-induced DNAzyme motor that facilitates an outstanding amplification reaction for the precise and sensitive detection of LDL through the simultaneous recognition of the target ApoB and cholesterol. This technique facilitates the direct and accurate quantification of the concentration of "intact" LDL particles, as opposed to assessing the cholesterol content or ApoB protein inside LDL. The elevated amplification efficiency of the exponential amplification reaction, in conjunction with the trans-cleavage activity of the Cas14a1/crRNA complex, facilitates sensitive LDL detection with a low limit of detection of 6.12 mg/dL. The unique properties of the proposed method offer significant advantages in selectivity, stability, and sensitivity, rendering it extremely appropriate for diagnostics in MAFLD.