Highly stable and specific molecular beacons encapsulated in cationic lipoplex nanoparticles and application thereof

A method of detecting the presence of a target DNA, a mRNA, or a microRNA, in a subject, comprising:

• a) providing a liquid sample comprising cells, circulating tumor cells (CTCs), or extracellular vesicles (EVs);
• b) contacting the cells, circulating tumor cells (CTCs), or extracellular vesicles (EVs) with a cationic lipoplex nanoparticle, wherein the cationic lipoplex nanoparticle comprises a nucleic acid probe, wherein the nucleic acid probe comprises at least one stem, at least one loop, an overhang section, and at least one fluorescent dye, and wherein the nucleic acid probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID No 2, SEQ ID No 4, SEQ ID No 5, SEQ ID No 6, SEQ ID No 7, SEQ ID No 9, SEQ ID No 11, SEQ ID No 12, and SEQ ID No 13;
• c) allowing the nucleic acid probe to hybridize to the target DNA, the mRNA, or the microRNA;
• and
• d) measuring a fluorescent signal to detect the target DNA, the mRNA, or the microRNA.