Visual Detection of Leishmania donovani and Leptomonas seymouri in Co–Infected Samples by Their Specific DNA Biomarker and Gold Nanoparticle

Abstract

Visceral leishmaniasis (VL) is a fatal tropical disease that often relapses in apparently recovered patients as post kalaazar dermal leishmaniasis (PKDL) in Indian subcontinent. Recently, the co‐infection of Leishmania donovani and another tripanosmatid, Leptomonas seymouri has been reported in VL and PKDL in this region. The coexistence of Leishmania imposter, Leptomonas in the clinical isolates and its follow up cultures has been challenging in immunological and vaccine development research against leishmaniasis, where maintenance of pure Leishmania culture is a prerequisite. The impact of this newly observed parasitic co‐habitation in diagnosis and management of VL and PKDL is yet to be ascertained. However, an early detection of this emerging co‐infection has become intriguing for research and medical management of the disease. Internal transcribed spacer‐1 (ITS‐1), in which Leishmania and Leptomonas differ in sequences, were used as the specific markers in the current assay. The color of gold nanoparticle visually got changed as target DNA isolated from either of the species interacted with designed, species‐specific oligonucleotide probes added externally. The current colorimetric assay to detect the co‐infection of Leishmania and Leptomonas is a robust, sensitive, high throughput, low cost and rapid method requiring no sophisticated instruments.

Rapid diagnosis of leishmania spp. in blood samples using gold nanoparticles.

“…Thus, increasing the local color density or its variation towards a specific color (20). This color variation depends more on the quantity and quality of the target material, as the color density varies with different concentrations of the target material (21). Therefore, the goal of obtaining the highest testing accuracy is the ensuring of the nanoparticles reach the target sequence.…”

Green Synthesis of Sodium Cholate Stabilized Silver Nanoparticles: An Effective Colorimetric Sensor for Hg2+ and Pb2+ Ions

“…So far there are many reports available on the sensing of heavy metal ions using noble metal nanoparticles in particular silver and gold nanoparticles (Ag and Au NPs) as colorimetric probe ,. The key advantages of these metal nanomaterials based assays are their high molar extinction coefficient, size and shape tunable optical properties, biocompatibility, high stability, good water solubility and the molecular recognition events can be directly visualized by the naked eye without any sophisticated instruments ,,. Besides, the selectivity and sensitivity of the NPs based on various analytes would be achieved by functionalization using suitable capping molecules.…”