Magnetic Nanoparticles PCR Enzyme-Linked Gene Assay for Quantitative Detection of BCR/ABL Fusion Gene in Chronic Myelogenous Leukemia

Application of iron oxide nanoparticles in the diagnosis and treatment of leukemia

Leukemia is a malignancy initiated by uncontrolled proliferation of hematopoietic stem cell from the B and T lineages, resulting in destruction of hematopoietic system. The conventional leukemia treatments induce severe toxic and a long series of unwanted side-effects which are caused by lack of specificity of anti-leukemic drugs. Recently, nanotechnology have shown tremendous application and clinical impact with respect to diagnosis and treatment of leukemia. According to considerable researches in the context of finding new nanotechnological platform, iron oxide nanoparticles have been gained increasing attention for the leukemia patients use. In this review, a short introduction of leukemia is described followed by the evaluation of the current approaches of iron oxide nanoparticles applied in the leukemia detection and treatment. The enormous advantages of iron oxide nanoparticles for leukemia have been discussed, which consist of the detection of magnetic resonance imaging (MRI) as efficient contrast agents, magnetic biosensors and targeted delivery of anti-leukemia drugs by coating different targeting moieties. In addition, this paper will briefly describe the application of iron oxide nanoparticles in the combined treatment of leukemia. Finally, the shortcomings of the current applications of iron-based nanoparticles in leukemia diagnosis and treatment will be discussed in particular.

Solvent-sensitive nanoparticle-enhanced PCR assay for the detection of enterotoxigenic Escherichia coli

Stimulus-responsive nanoparticles are among the most utilized nanoscale materials in biomedical applications. As these nanoparticles exhibit a manipulable response to a particular stimulus, such as pH, heat, and organic solvent, they are potential signalling units in diagnostic assays. This study aims to enhance the limit of detection and reduce the turnaround time of magnetic nanoparticle polymerase chain reaction (PCR) enzyme-linked gene assay (MELGA), an advanced PCR-based technique termed the solvent-sensitive nanoparticle (SSNP)-enhanced PCR assay. This technique was proposed to detect pathogenic enterotoxigenic Escherichia coli (ETEC) through applying stimulus-responsive nanoparticles. The SSNPs were elaborated with three main components, including mesoporous silica nanoparticles as a structural unit, organic dye (Nile red) as a payload, and the corresponding organic solvent-sensitive polymer shell as "gatekeeper" (poly(maleic anhydride-alt-methyl vinyl ether, PMAMVE). A suitable organic solvent capable of inducing polymer swelling and dye dissolution was investigated by considering a solubility parameter. Using ethanol, the encapsulated Nile red can diffuse out of the SSNPs faster than other solvents and reach a constant concentration within 15 min. For the PCR inhibition study, various SSNPs concentrations (10-30 μg/reaction) were mixed with the ETEC gene and PCR reagent. The results showed that the particles in this concentration range did not inhibit PCR. By comparing the efficacy of conventional PCR, MELGA, and SSNP-enhanced PCR assay, the proposed technique showed a better detection limit than that of PCR, whereas that of MELGA was the lowest. Moreover, compared to MELGA or conventional PCR, this technique provided remarkably faster results in the postamplification process.

Increased sensitivity of enterotoxigenic Escherichia coli detection in stool samples using oligonucleotide immobilized-magnetic nanoparticles

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A rapid detection of ETEC DNA with high sensitivity and specificity.

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The combination between magnetic nanoparticles and molecular technique.

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100-folds increase of sensitivity compared with gold standard.

PCR detection of enterotoxigenic Escherichia-coli (ETEC) can be used directly on stool sample. However, it still has limitations due to presence of PCR inhibitors and interferences. This study, oligonucleotide primer specific to ETEC was immobilized onto MNPs and applied for separation and enrichment of ETEC-DNA from contaminants in stool after boiling. DNA separation efficiency was evaluated using conventional PCR and magneto-PCR-enzyme linked-gene-assay (MELGA). Due to high specificity of primer and efficiency of nanoparticles to bring down PCR inhibitors, DNA separation using primer-immobilized-MNPs exhibited 100-fold increase of sensitivity compared to that using simple boiling. Moreover, the sensitivities in stool were increased from 10⁸ to 10⁶ CFU/mL and 10⁴ to 10² CFU/mL when PCR products were detected by gel electrophoresis and MELGA, respectively. Results suggested that oligonucleotide-immobilized-MNPs combined with boiling DNA extraction method was successfully used to separate the DNA of ETEC in stool with high sensitivity using MELGA.

Urinary PCA3 detection in prostate cancer by magnetic nanoparticles coupled with colorimetric enzyme-linked oligonucleotide assay

PCA3 is one of the most prostate cancer-specific genes described to date. Of note, PCA3 expression is detectable at high level in the urine of prostate cancer (PCa) patients. Accordingly, PCA3 is an ideal biomarker for PCa diagnosis. Several techniques for the measurement of this biomarker in urine have been developed but there are still some drawbacks. In this study, magnetic nanoparticle-based PCR coupled with streptavidin-horseradish peroxidase and a substrate for colorimetric detection was established as a potential assay for urinary PCA3 detection. The method provided a high specificity for PCA3 gene in LNCaP prostate cancer cell line. Additionally, this technique could detect PCA3 at femtogram level which was approximately 1,000-fold more sensitive than the conventional RT-PCR followed by agarose gel electrophoresis. The effectiveness of the method was assessed by PCA3 detection in clinical specimens. The relative PCA3 expression of PCa patients determined by this assay was significantly greater than that of benign prostatic hyperplasia (BPH) patients and healthy controls. The results of our test were comparable with the results of qRT-PCR. The proposed method is promising to distinguish between cancerous and non-cancerous groups. Altogether, this simple assay is practicable and useful for prostate cancer diagnosis.

Magnetic particles for in vitro molecular diagnosis: From sample preparation to integration into microsystems

Colloidal magnetic particles (MPs) have been developed in association with molecular diagnosis for several decades. MPs have the great advantage of easy manipulation using a magnet. In nucleic acid detection, these particles can act as a capture support for rapid and simple biomolecule separation. The surfaces of MPs can be modified by coating with various polymer materials to provide functionalization for different applications. The use of MPs enhances the sensitivity and specificity of detection due to the specific activity on the surface of the particles. Practical applications of MPs demonstrate greater efficiency than conventional methods. Beyond traditional detection, MPs have been successfully adopted as a smart carrier in microfluidic and lab-on-a-chip biosensors. The versatility of MPs has enabled their integration into small single detection units. MPs-based biosensors can facilitate rapid and highly sensitive detection of very small amounts of a sample. In this review, the application of MPs to the detection of nucleic acids, from sample preparation to analytical readout systems, is described. State-of-the-art integrated microsystems containing microfluidic and lab-on-a-chip biosensors for the nucleic acid detection are also addressed.

Simultaneous detection of 45 fusion genes in leukemia by dual-color fluorescence real-time PCR

INTRODUCTION

Detection of recurrent genetic abnormalities is of great significance for a refined diagnosis and assessment of prognosis in leukemia. Conventional nested reverse transcription PCR is labor intensive and time-consuming.

METHODS

We have developed a novel dual-color TaqMan probe-based real-time PCR method for the simultaneous screening of 45 fusion transcripts in 12 parallel reactions. The method was tested and validated with cell lines carrying known fusion transcripts and patient samples.

RESULTS

A multiplex real-time PCR method was successfully developed for rapid detection of 45 fusion genes and validated for 15 of the more commonly detected fusion genes. Intra-assay reproducibility assessed for the most frequent rearrangements ranged from 0.41% to 0.74% for the coefficient of variation (CV) of cycle threshold (Ct) and the interassay reproducibility ranged from 1.62% to 2.83% in five separate experiments. The lowest detection limit for the translocations tested ranged between 1 : 16 000 and 1 : 32 000. Validation of the method with 213 patient samples showed 100% specificity and excellent consistence with conventional nested RT-PCR.

CONCLUSION

Overall, we believe that this method is easily applicable, cost-effective, and clinically useful for a rapid screening of fusion genes in the initial diagnostic phase of leukemia. Its use can also be extended to the monitoring of minimal residual disease.

Enhanced Sensitivity for Detection of Plasmodium falciparum gametocytes by magnetic nanoparticles combined with enzyme substrate system

The highly sensitive and specific detection of Pfg377 gene of Plasmodium falciparum gametocyte using Magnetic Nanoparticles PCR Enzyme-Linked Gene Assay (MELGA) was successfully developed. The MELGA included amplification of the Pfg377 gene by polymerase chain reaction (PCR) using magnetic nanoparticles (MNPs)-conjugated forward primer and biotinylated reverse primer, followed by post-analytical process using horseradish peroxidase (HRP)-conjugated streptavidin (SA). The complexes of MELGA product were incubated with the peroxidase substrate and hydrogen peroxide to produce the signal for colorimetric measurement. Altogether, the MELGA technique provided a highly sensitive and specific detection at 1 P. falciparum gametocyte/µL, which was more efficient than that of microscopic examination and rapid diagnostic tests (RDTs). Additionally, the MELGA could detect target gene at femtogram level, which was greater sensitive than the conventional PCR, nested PCR and loop-mediated isothermal amplification (LAMP). The MELGA technique could become a novel and practical method that overcome limitation of traditional gametocyte detection.