Electrochemical magneto-immunoassay based on Mycobacterium leprae mimotope for serological diagnosis of leprosy

Abstract

Leprosy is an infectious disease classified as Neglected Tropical Disease (NTD) by the World Health Organization (WHO). Its diagnosis is challenging, relying on clinical symptoms and invasive procedures. Delays can cause severe physical disability, including hand, foot, and eye impairments. Herein, we describe the development of a magneto-immunoassay based on an electrochemical disposable microfluidic device for the serological diagnosis of leprosy. The assay makes use of magnetic particles (MPs) modified with Mycobacterium leprae mimotope as a probe to capture and separate target-specific antibodies from serum samples. The antibody anti-M. leprae was detected using the anti-human antibody IgG conjugated with horseradish peroxidase enzyme as an electrochemical maker. The magneto-immunoassay was applied in serum samples from healthy subjects and patients diagnosed with leprosy classified as paucibacillary (PB) and multibacillary (MB). The results showed that the method could differentiate between negative and positive patients (AUC = 0.990) with high clinical sensitivity (91.2%) and specificity (100.0%). In addition, the assay showed the capability to differentiate between paucibacillary and multibacillary with sensitivities of 88.9% and 93.7%, respectively, indicating that the device can be used to guide the treatment of positive cases. Thus, magneto-immunoassay based on the use of a disposable microfluidic device demonstrated to be a valuable tool for the early diagnosis of leprosy which can help the public health system to reduce disability cases and even control and eliminate the disease by interrupting the chain of transmission.