Optically encoded multifunctional nanospheres for one-pot separation and detection of multiplex DNA sequences

An electrochemical sensing strategy for the detection of the hepatitis B virus sequence with homogenous hybridization based on host–guest recognition

Schematic for electrochemically sensing DNA with hybridization in homogeneous solutionviahost–guest recognition based on MNPs/β-CD.

Highly sensitive DNA detection using cascade amplification strategy based on hybridization chain reaction and enzyme-induced metallization

A novel highly sensitive colorimetric assay for DNA detection using cascade amplification strategy based on hybridization chain reaction and enzyme-induced metallization was established. The DNA modified superparamagnetic beads were demonstrated to capture and enrich the target DNA in the hybridization buffer or human plasma. The hybridization chain reaction and enzyme-induced silver metallization on the gold nanoparticles were used as cascade signal amplification for the detection of target DNA. The metalization of silver on the gold nanoparticles induced a significant color change from red to yellow until black depending on the concentration of the target DNA, which could be recognized by naked eyes. This method showed a good specificity for the target DNA detection, with the capabilty to discriminate single-base-pair mismatched DNA mutation (single nucleotide polymorphism). Meanwhile, this approach exhibited an excellent anti-interference capability with the convenience of the magentic seperation and washing, which enabled its usage in complex biological systems such as human blood plasma. As an added benefit, the utilization of hybridization chain reaction and enzyme-induced metallization improved detection sensitivity down to 10pM, which is about 100-fold lower than that of traditional unamplified homogeneous assays.

Efficient preparation of magnetic quantum dot barcodes

Quantum dot (QD)-encoded magnetic barcodes were prepared through a highly efficient membrane emulsification-solvent evaporation approach. Our study demonstrates the great potential of these QD-encoded magnetic barcodes for both magnetic separation and multiplex suspension assays.

DNA induced intense plasmonic circular dichroism of highly purified gold nanobipyramids

We report a strong and reversible CD response through the assembly of helical DNA and Au nanobipyramids (Au NBPs). Compared with common spherical Au nanoparticles or anisotropic Au nanorods, highly purified Au NBPs possess a more intense electromagnetic field and improved surface plasmon resonance. Thus, the assembly of DNA and Au NBPs exhibits an obviously enhanced plasmonic CD response. When the plasmonic CD is used for DNA detection, it shows high sensitivity and good reproducibility.