Fluorometric determination of the breast cancer 1 gene based on the target-induced conformational change of a DNA template for copper nanoclusters

An electrochemical biosensor for the detection of BRCA1 based on MOF-derived CeO2@CuS nanosheets with high electrocatalytic H2O2 reduction performance

BACKGROUND

Since the incidence of breast cancer ranks first among female malignant tumors, early diagnosis and treatment of breast cancer are crucial to women's health. Therefore, the detection and monitoring of breast cancer susceptibility gene (BRCA1) is particularly important. In this paper, an electrochemical biosensor was developed to detect BRCA1 based on MOF-derived CeO2@CuS nanosheets with efficient electrocatalytic activity of H2O2 reduction.

RESULTS

CeO2 nanotube derived from MOF possessed excellent charge transfer ability and high specific surface area, making it an ideal substrate for loading CuS nanosheets. The combination of CeO2 and CuS enhanced the electrocatalytic activity and conductivity of H2O2 redox reaction. Then gold nanoparticles (Au) were introduced to synthesize Au@CeO2@CuS to further improve conductivity and electrocatalytic activity. Based on the excellent properties of the above synthetic materials, the non-enzymatic electrochemical sensing platform for detecting BRCA1 were constructed. The proposed method demonstrated wide linearity ranges and low detection limits for detecting BRCA1 (0.1 pmol/L - 10 nmol/L, 0.02 fmol/L), respectively.

SIGNIFICANCE

These showed that the sensing strategy provides a new approach for the detection of BRCA1 and has important significance for the early diagnosis and treatment of breast cancer.

Metal Nanocluster-Based Biosensors for DNA Detection

The early detection of genetic diseases is a critical need in modern medicine, underscoring the importance of developing deoxyribonucleic acid (DNA) biosensors. In recent years, metal nanoclusters (MNCs) have demonstrated significant potential as biosensors for DNA detection due to their ultra-small size, excellent photostability, bright photoluminescence, low toxicity and other outstanding properties. This review firstly discusses the characteristics of MNCs, which are effective in the early diagnosis of DNA diseases. Subsequently, different synthesis methods of MNCs are introduced. In the following section, DNA sensors based on different types of MNCs and their respective detection mechanisms are discussed in detail. Finally, the opportunities and challenges faced by DNA sensors based on MNCs are analyzed.

Dual-mode colorimetric and fluorescence detection of BRCA1 based on a CRISPR-Cas12a system

Breast cancer, the most common malignant tumor in the world, seriously threatens human life and health. Early diagnosis of breast cancer may help enhance the survival rate. In this work, a colorimetric and fluorescent dual-mode biosensor based on the CRISPR-Cas12a system was constructed to detect the breast cancer biomarker BRCA1. The intact G4 DNA, with the assistance of K+ and hemin, catalyses the oxidation of o-phenylenediamine (OPD) with the assistance of hydrogen peroxide (H2O2), generating the oxidation product 2,3-diaminophenazine (DAP), which has distinct absorption and fluorescence peaks. The presence of the target BRCA1 activates the trans-cleavage activity of CRISPR-Cas12a, leading to the cleavage of G4 DNA and inhibiting the catalytic oxidation of OPD. Target BRCA1 was quantitatively determined by measuring both the absorbance and fluorescence intensity of DAP. The detection limits were calculated to be 0.615 nM for the colorimetric method and 0.289 nM for the fluorescence method. The dual-mode biosensor showed good selectivity and reliability for BRCA1 and can resist interference from complex substrates, and it has great potential in biomedical detection.

Graphene-Oxide and Ionic Liquid Modified Electrodes for Electrochemical Sensing of Breast Cancer 1 Gene

Graphene-oxide and ionic liquid composite-modified pencil graphite electrodes (GO-IL-PGEs) were developed and used as a sensing platform for breast cancer 1 (BRCA1) gene detection. The characterization of GO-IL modified electrodes was executed by scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The nucleic-acid hybridization was monitored by a differential pulse voltammetry (DPV) technique by directly measuring the guanine oxidation signal without using any indicator. The effects of the IL concentration, the probe concentration, and the hybridization time were optimized to the biosensor response. The limit of detection (LOD) was calculated in the concentration range of 2–10 μg/mL for the BRCA1 gene and found to be 1.48 µg/mL. The sensitivity of the sensor was calculated as 1.49 µA mL/µg cm². The developed biosensor can effectively discriminate the complementary target sequence in comparison to a three-base-mismatched sequence or the non-complementary one.