Magnetic-Immuno-Loop-Mediated Isothermal Amplification Based on DNA Encapsulating Liposome for the Ultrasensitive...

Determination of proteins, especially low-abundance proteins with high sensitivity and specificity, is essential for characterizing proteomes and studying their biochemical functions. Herein, a novel Magnetic-Immuno-Loop-Mediated Isothermal Amplification (Im-LAMP) based on DNA-encapsulating liposomes (liposome-Im- LAMP), was developed for trace amounts of proteins. To the best of our knowledge, this is our first report about the magnetic Im-LAMP approach based on liposomes encapsulated template DNA as the detection reagent. The DNA template was released from liposomes and then initiated an Im-LAMP reaction, generating the fluorescence signal with high sensitivity and rapidity. This technique was applied for the determination of P-glycoprotein as a model protein. It was demonstrated that the technique exhibited a dynamic response to P-glycoprotein ranging from 1.6*10^-2 to 160 pg/ml with a greatly low detection limit of 5*10^-3 pg/ml (5 fg/ml) which is substantially better than conventional enzyme-linked immunosorbent assays (ELISA). This ultra sensitivity was attributed to the LAMP reaction initiated by the enormous DNA targets encapsulated in liposomes. This magnetic liposome-Im-LAMP as an alternative approach is attractive for applications in other low-abundance proteins detection in clinical diagnostics.