Recent trends in biosensors for leukemia diagnosis: A critical overview of electrochemical and optical approaches for clinical applicability

Leukemia is a hematopoietic cancer with heterogeneous manifestations. For the initial diagnosis and risk stratification of patients, it is necessary to perform several tests together to delineate the prognosis and appropriate therapy. Initial tests involve the evaluation and detection of leukemic cells with complete blood count and flow cytometry with immunophenotyping. However, for decisive therapy classification, tests such as karyotyping, fluorescent in situ hybridization, and RT-PCR (transcriptase reaction combined with polymerase chain reaction) are indispensable. In view of this, various biosensors have been developed with the aim of addressing some of these limitations. This is because these devices are designed for low-cost, simple, and quickly interpretable detection with accuracy. Thus, this review discusses different strategies, techniques, and tools used in leukemia biosensors as well as the main challenges for the real applicability of bio-devices in diagnostic routines. In this regard, biosensors applied to leukemia have been subdivided into the detection of cells and oncogenes. He electrochemical and optical techniques used as transduction methods are discussed, along with nanostructuring, biomarkers, challenges, and perspectives of these tools. Additionally, general biomarkers of interest and innovative strategies involving the combination of different biomolecules are also discussed. Some challenges encountered include the application of biosensors in miniaturized systems compatible with lab-on-chip technologies, as well as devices capable of addressing the complexity of markers in relation to the molecular heterogeneity present in leukemia cases.