Coupling a universal DNA circuit with graphene sheets/polyaniline/AuNPs nanocomposites for the detection of BCR/ABL fusion gene

Various types of electrochemical biosensors for leukemia detection and therapeutic approaches

Leukemia often initiates following dysfunctions in hematopoietic stem cells lineages. Various types of leukemia, including acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia (CML), acute promyelocytic leukemia (APL), and human T-cell leukemia/lymphoma virus type 1 (HTLV-1) can thus call for different diagnosis and treatment options. One of the most important subjects in leukemia is the early detection of the disease for effective therapeutic purposes. In this respect, biosensors detecting the molecules of deoxyribonucleic acid (DNA) as analytes are called genosensors or DNA biosensors. Electrochemical sensors, as the most significant approach, also involve reacting of chemical solutions with sensors to generate electrical signals proportional to analyte concentrations. Biosensors can further help detect cancer cells in the early stages of the disease. Moreover, electrochemical biosensors, developed based on various nanomaterials (NMs), can increase sensitivity to the detection of leukemia-related genes, e.g., BCR/ABL as a fusion gene and promyelocytic leukemia/retinoic acid receptor alpha (PML/RARα). Therefore, the present review reflects on previous studies recruiting different NMs for leukemia detection.

Aptamer based high throughput colorimetric biosensor for detection of staphylococcus aureus

To develop a high throughput colorimetric biosensor for detection of Staphylococcus aureus (SA) based on specific aptamer and catalysis of dsDNA-SYBR Green I (SG I) complex. SA specific aptamer was immobilized on a 96-well plate by hybridization with the capture probe anchored on the plate surface through streptavidin-biotin binding. In presence of SA, the aptamer was dissociated from the capture probe-aptamer duplex due to the stronger interaction between the aptamer and SA. The consequent single-strand capture probe could be hybridized with a three-way junction (TWJ) probe. With the presence of SG I, the dsDNA-SG I complex catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) under photo-irradiation, producing sensitive photo-catalyzed colorimetric response to SA. Under the optimal conditions, the proposed method could directly detect SA with the limit of detection (LOD) at 81 CFU mL⁻¹ in PBS buffer in 5.5 hours, which demonstrated the sensitive and fast quantification of target pathogenic bacteria. The method showed weak colorimetric signal to Escherichia coli and Pseudomonas aeruginosa, indicating the high specificity for SA. In addition, the method can simultaneously detect 96 samples which can be used for high throughput analysis. The designed method may become a powerful tool for pathogenic microorganisms screening in clinical diagnostics, food safety and environmental monitoring.

Au nanoparticle in situ decorated RGO nanocomposites for highly sensitive electrochemical genosensors

A novel hybrid nanocomposite formed by RGO flakes, surface functionalized by 1-pyrene carboxylic acid (PCA), densely and uniformly in situ decorated by Au NPs, is reported, for miRNA detection.