Ultraviolet/Visible and Near-Infrared Dual Spectroscopic Method for Detection and Quantification of Low-Level Malaria Parasitemia in Whole Blood

Abstract

The scourge of malaria infection continues to strike hardest against pregnant women and children in Africa and South East Asia. For global elimination, testing methods that are ultrasensitive to low-level ring-staged parasitemia are urgently required. In this study, we used a novel approach for diagnosis of malaria infection by combining both electronic ultraviolet−visible (UV/vis) spectroscopy and near infrared (NIR) spectroscopy to detect and quantify low-level (1−0.000001%) ring-staged malariainfected whole blood under physiological conditions uisng Multiclass classification using logistic regression, which showed that the best results were achieved using the extended wavelength range, providing an accuracy of 100% for most parasitemia classes. Likewise, partial least-squares regression (PLS-R) analysis showed a higher quantification sensitivity (R 2 = 0.898) for the extended spectral region compared to UV/vis and NIR (R 2 = 0.806 and 0.556, respectively). For quantifying different-stage blood parasites, the extended wavelength range was able to detect and quantify all thePlasmodium falciparum accurately compared to testing each spectral component separately. These results demonstrate the potential of a combined UV/vis−NIR spectroscopy to accurately diagnose malaria-infected patients without the need for elaborate sample preparation associated with the existing mid-IR approaches.

Visible microspectrophotometry coupled with machine learning to discriminate the erythrocytic life cycle stages of P. falciparum malaria parasites in functional single cells

“…Although the 663 nm haemozoin band is not evident in malaria infected functional cells, there are slight shifts in the Soret band between spectra from the control and ABS cells consistent with a previous report analysing isolated P. falciparum parasites embedded in saline. 23,29,37 In the control spectrum of uninfected red blood cells, the Soret band was observed at 418 nm, which is attributed to oxygenated RBCs. 23 However, the presence of haemozoin in the ABS parasites results in slight broadening of the Soret band and the peak is shifted to 430 nm.…”

“…5B and C and in previous UV-Vis studies of haemozoin/ β-haematin. 23,29,35 Support vector machine classification SVM models were similarly developed to further explore the differences in the dataset. Each model's accuracy was scored based on the cross-validation errors (Root Mean Squared Error of Validation; RMSEV).…”

“…More recently, we have explored more inexpensive options based on near infrared and ultraviolet-visible (UV/Vis) spectroscopy to quantify parasitaemia in isolated RBCs 28 and aqueous blood samples, 29 but not to discriminate various ABS parasites at the single cell level. We showed that by combining UV/Vis and NIR region of the electromagnetic spectrum together improved parasitaemia quantification.…”

“…We showed that by combining UV/Vis and NIR region of the electromagnetic spectrum together improved parasitaemia quantification. 29 The visible part of the electromagnetic (400–700 nm) is particularly important for analysing aqueous samples due to the low absorption of water in this region. 30 Hitherto, no study has successfully discriminated different ABS parasites in their physiological state at the single cell level using visible spectroscopy.…”

A Combined Near-Infrared and Mid-Infrared Spectroscopic Approach for the Detection and Quantification of Glycine in Human Serum

“…The spectral acquisition was performed using a miniature, portable and hand-held spectrometer (manufactured by Neospectra Si-Ware systems (Menlo Park, CA, USA)) commercialized by Hydrix MedTech (Melbourne, Australia) that incorporates an integrated spectral sensor in the NIR regime between 2500 nm and 1350 nm. The spectrometer has been previously applied to detect and quantify malaria parasitemia in dried [39] and aqueous blood [40]. Technically, the Michelson interferometer was fabricated monolithically by exploiting the Micro-Electro-Mechanical System (MEMS) technology, which enabled the micropatterning or micromachining of the prime functional part of the spectrometer.…”