Homogeneous Visual and Fluorescence Detection of Circulating Tumor Cells in Clinical Samples via Selective Recognition Reaction and Enzyme-Free Amplification

Abstract

Here we report a simple all-nucleic-acid enzymefree catalyzed hairpin assembly assisted amplification strategy with quantum dots (QDs) as the nanoscale signal reporter for homogeneous visual and fluorescent detection of A549 lung cancer cells from clinical blood samples. This work was based on the phenomenon that CdTe QDs can selectively recognize Ag + and C-Ag + -C and by using mucin 1 as the circulating tumor cells (CTCs) marker and aptamer as the recognition probe. Under optimized conditions, the limits of detections as low as 0.15 fg/mL of mucin 1 and 3 cells/mL of A549 cells were achieved with fluorescence signals. A 1 fg/mL concentration of mucin 1 and 100 cells/mL of A549 can be distinguished by the naked eye. This method was used to quantitatively analyze CTCs in 51 clinical whole blood samples of patients with lung cancer. The levels of CTCs detected in clinical samples by this method were consistent with those obtained using the folate receptor-polymerase chain reaction clinical test kit and correlated with radiologic and pathological findings.

Simultaneous Homogeneous Fluorescence Detection of AFP and GPC3 in Hepatocellular Carcinoma Clinical Samples Assisted by Enzyme-Free Catalytic Hairpin Assembly

“…11−16 Especially, CHA endows with higher catalytic efficiency, lower background signals, and a simpler and more stable reaction system. 13 In amplification technologies involving nanomaterials, materials with luminescent properties can boost analytical sensitivity while laying the foundation for the construction of analytical methods for visual reading. 17−19 For instance, quantum dots (QDs), nanoclusters, N-methyl mesoporphyrin IX (NMM) small molecules, lanthanide coordination complexes, and so forth have been applied in the sensing field.…”

“…In contrast, nucleic acid aptamers that are simple to synthesize, easy to store, economical, and easy to introduce functional groups have received extensive attention in sensing fields . In addition, the biggest benefit of nucleic acid aptamers as recognition probes is the ease with which multiple nucleic acid amplification strategies may be integrated to enhance the detection sensitivity of the method. − Among several signal amplification techniques, enzyme-free nucleic acid- and nanomaterial-assisted methods such as nonenzyme-catalyzed hairpin assembly (CHA), hybrid chain reaction, and DNAzyme amplification technologies have been widely used by the virtue of their simple and economical design and favorable amplification effect. − Especially, CHA endows with higher catalytic efficiency, lower background signals, and a simpler and more stable reaction system . In amplification technologies involving nanomaterials, materials with luminescent properties can boost analytical sensitivity while laying the foundation for the construction of analytical methods for visual reading. − For instance, quantum dots (QDs), nanoclusters, N -methyl mesoporphyrin IX (NMM) small molecules, lanthanide coordination complexes, and so forth have been applied in the sensing field.…”

A cascade Fermat spiral microfluidic mixer chip for accurate detection and logic discrimination of cancer cells

“…[25][26][27][28] Fluorescent biosensors have a wide range of applications in analytical detection, medical analysis, and bioimaging due to their strong fluorescence, high sensitivity, and ease of operation. [29][30][31] Therefore, it is important to develop fluorescent biosensors integrated with microfluidic chips for directly detecting cancer cells and distinguishing cancer cells from normal cells. It is worth noting that copper ions (Cu 2+ ) can catalyze the reaction system of Amplex Red (AR) and hydrogen peroxide (H 2 O 2 ) and oxidize the non-fluorescent substance AR to the highly fluorescent substance resorufin (ox-AR).…”

Homogeneous Binary Visual and Fluorescence Detection of Tetanus Toxoid in Clinical Samples Based on Enzyme-Free Parallel Hybrid Chain Reaction

“…Nucleic acid amplification technology includes both enzyme-based reactions, such as polymerase chain reaction and so forth, − and nonenzyme-based reactions, such as catalytic hairpin assembly, hybridization chain reaction (HCR), and DNAzymes. − Compared to enzyme-based reactions, the enzyme-free amplification system is more straightforward and easy to perform. Amplification strategies making use of nanomaterials are also highly attractive because of their intrinsic enzyme-like catalytic properties, the ability to encapsulate massive reactants, or their ability to react precisely and quickly with metal ions. − Nanomaterials are also ideal tools to develop POCT with easily detectable readouts, such as changes in color, pressure, blood glucose, distance, weight, and temperature. − Many nanomaterial-assisted POCT approaches are performed in room temperature in an instrument-free manner and thus are very straightforward to use. , …”