Optical coding of fusion genes using multicolor quantum dots for prostate cancer diagnosis

Abstract

Recent studies have found that prostate cancer expresses abnormal genetic markers including multiple types of TMPRSS2–ERG fusion genes. The expression level of different TMPRSS2–ERG fusion genes is correlated to pathologic variables of aggressive prostate cancer and disease progression. State-of-the-art methods for detection of TMPRSS2–ERG fusion genes include reverse transcription polymerase chain reaction (RT-PCR) with a detection limit of 1 fmol at urinary condition. RT-PCR is time consuming, costly, and inapplicable for multiplexing. Ability to identify multiple fusion genes in a single sample has become important for diagnostic and clinical purposes. There is a need for a sensitive diagnostic test to detect multiple TMPRSS2–ERG fusion genes for an early diagnosis and prognosis of prostate cancer. Here, we propose to develop an assay for prostate cancer diagnosis using oligonucleotide-functionalized quantum dot and magnetic microparticle for optical detection of rearranged TMPRSS2–ERG fusion genes at a low concentration in urine. We found that our assay was able to identify three different types of fusion gene with a wide detection range and detection limit of 1 fmol (almost the same level of the RT-PCR result reported). Here, we show detection of multiple TMPRSS2–ERG fusion genes using color-coded oligonucleotides in cell lysate and urine.

Quantitative Single-Cell Analysis of Isolated Cancer Cells with a Microwell Array

“…Instead of targeting the cells with a conventional fluorescent dye, for which the signal decreases over time due to the photobleaching effect, QD nanoprobes were used to quantify the biomarkers in the prostate-cancer cell lines (Figure ). Immunofluorescence with QD nanoprobes is useful for subsequent quantitative analysis because of several advantageous optical properties of QDs for bioimaging. − The QDs are 20–100 times brighter than traditional fluorescent dyes, and they show stable optical characters. , The number of QDs was quantitated on the basis of the fluorescence intensity per square micrometer . The number of QDs is equivalent to the number of the biomarkers, and thus the number density of biomarkers was calculated on the basis of the fluorescence intensity.…”

Nanotechnology-Based Strategies for Early Cancer Diagnosis Using Circulating Tumor Cells as a Liquid Biopsy

“…This property is especially significant in the application of QDs for enhancing the sensitivity of surface marker-dependent CTC capture and sorting, particularly when CTCs may be in low abundance at the early stages of the disease. The size dependence of the absorption and emission wavelengths of QDs enables the tunable design of QDs for a range of imaging applications, especially in multicolor labeling for the simultaneous detection of multiple targets 79 . In addition, size-tuned QDs with different emission wavelengths corresponding to the same excitation wavelength can be applied to capture and sort heterogeneous CTCs 80 .…”

Rapid detection of quantum dot immune chromatography nasopharyngeal carcinoma EBNA1 antibody

“…Compared to the traditional organic molecular fluorescent materials, QD has the following advantages: i) wide and continuous excitation spectrum, with large absorption coefficient and high quantum yield; ii) narrow and symmetric emission spectrum without trailing; iii) strong fluorescence intensity and high signal to noise ratio; iv) good light stability and strong ability to resist photobleaching; v) emission wavelength changes with particle size. Owing to its unique chemical and optical properties, QD has gradually been applied in tumor biological medicine, such as prostate cancer ( 4 ), pancreatic cancer ( 5 ), breast cancer ( 5 ), liver cancer ( 6 ), colorectal cancer ( 7 ) and nasopharyngeal carcinoma (NPC) ( 8 ). This study aimed to explore the 605 nm carboxyl of water-soluble quantum dots to assess the practicability of the NPC marker EBNA1 antibody.…”