Our Publications

Microfluidic device: A versatile biosensor platform to multiplex aptamer‐based detection of malaria biomarkers

Abstract Plasmodium falciparum malaria remains a dominant infectious disease that affects Africa than the rest of the world, considering its associated cases and death rates. It's a febrile illness that produces several reliable biomarkers, for example, P. falciparum lactate dehydrogenase ( Pf LDH), P. falciparum Plasmodium glutamate dehydrogenase (PfGDH), and P. falciparum histidine‐rich proteins (HRP‐II) in blood circulatory system that can easily be employed as targets in rapid diagnostic tests (RDTs). In recent times, several DNA aptamers have been developed via SELEX technology to detect some specific malaria biomarkers ( Pf LDH, Pv LDH, HRP‐II, PfGDH) in a biosensor mode with good binding affinity properties to overcome the trend of cross‐reactivity, limited sensitivity and stability problems that have been observed with immunodiagnostics. In this review, we summarized existing diagnostic methods and relevant biomarkers to suggest promising approaches to develop sensitive and species‐specific multiplexed diagnostic devices enabling effective detection of malaria in complex biological matrices and surveillance in the endemic region.

Distribution and Molecular Characterization of Clinically Relevant Acinetobacter Species from Selected Freshwater Sources in the Eastern Cape Province, South Africa

Background: Several Acinetobacter species live in different ecosystems, such as soil, freshwater, wastewater, and solid wastes, which has attracted considerable research interests in public health and agriculture. Methods: We assessed the distribution of Acinetobacter baumannii and Acinetobacter nosocomialis in three freshwater resources (Great Fish, Keiskemma, and Tyhume rivers) in South Africa between April 2017–March 2018. Molecular identification of Acinetobacter species was performed using Acinetobacter-specific primers targeting the recA gene, whilst confirmed species were further delineated into A. baumannii and A. nosocomialis. Similarly, virulence genes; afa/draBC, epsA, fimH, OmpA, PAI, sfa/focDE, and traT in the two Acinetobacter species were assessed. Results: Our finding revealed that 410 (48.58%) and 23 (2.7%) of the isolates were confirmed as A. baumannii and A. nosocomalis, respectively. Additionally, three hundred and eight (75.12%) A. baumannii and three (13.04%) A. nosocomialis exhibited one or more of the virulence genes among the seven tested. OmpA was the most prevalent virulence gene in A. baumannii in freshwater sources. Conclusions: The distribution of clinically important Acinetobacter species in the freshwater sources studied suggests possible contamination such as the release of hospital wastewater and other clinical wastes into the environment thereby posing a risk to public health.

A microfluidic paper analytical device using capture aptamers for the detection of PfLDH in blood matrices

Abstract Background The prevalence and death rate arising from malaria infection, and emergence of other diseases showing similar symptoms to malaria require the development of malaria-specific and sensitive devices for its diagnosis. To address this, the design and fabrication of low-cost, rapid, paper-based analytical devices (µPAD) using surface-immobilized aptamers to detect the presence of a recombinant malarial biomarker— Plasmodium falciparum lactate dehydrogenase (r Pf LDH)—is reported in this study. Methods Test zones on paper surfaces were created by covalently immobilizing streptavidin to the paper, subsequently attaching biotinylated aptamers to streptavidin. Aptamers selectively bound r Pf LDH. The measurement of captured r Pf LDH enzyme activity served as the means of detecting this biomarker. Enzyme activity across three replicate sensors was digitally quantified using the colorimetric Malstat assay. Results Screening of several different aptamers reported in the literature showed that aptamers rLDH7 and 2008s immobilized in this manner specifically recognised and captured Pf LDH. Using rLDH7, the sensitivity of the µPAD sensor was evaluated and the µPAD sensor was applied for preferential detection of r Pf LDH, both in buffered solutions of the protein and in spiked serum and red blood cell lysate samples. In buffered solutions, the test zone of the µPAD sensor exhibited a K D of 24 ± 11 nM and an empirical limit of detection of 17 nM, respectively, a limit similar to commercial antibody-based sensors exposed to r Pf LDH. The specific recognition of 133 nM r Pf LDH in undiluted serum and blood samples was demonstrated by the µPAD. Conclusion The reported µPAD demonstrates the potential of integrating aptamers into paper-based malarial rapid diagnostic tests. Graphical Abstract

Co-immobilization of cellulase extracted from Schizophylum commenfr and Saccharomyces cerevisieae in the bioconversion of sugar cane bagasse to ethanol

The production of ethanol from sugar cane bagasse using co-immobilized yeast cells (saccharomyces cerevisieae Y300) and crude cellulase enzyme extracted from mushroom, Schizophylum commenfr, was studied. The yeast cell and cellulase enzyme were immobilized on activated bone for simultaneous saccharification of sugar cane bagasse and ethanol production.

Modification of Starch Extracted from Cassava with Acidified Ethanol

Development of paper-based aptasensors for detection of Plasmodium falciparum lactate dehydrogenase in malaria

A comparative study of functional and structural properties of starch extracted from Dioscorea rotundata and Colocasia esculenta

This study was designed to compare some functional and structural properties of yam ( Dioscorea rotundata ) and cocoyam ( Colocasia esculenta ) starches. The yield, swelling power, amylose content, paste clarity, and viscosity of yam and cocoyam starches were determined. Likewise, the structural conformation of the starches was evaluated using optical and scanning electron microscopy as well as FTIR spectroscopy. The result showed that, the yield, swelling power, amylose content, and paste clarity of yam and cocoyam starches were 33.38% (217 ± 0.88 g) and 25% (108.75 ± 0.88 g); 38.4 ± 0.2 g/g and 33.4 ± 0.1 g/g; 25.96 ± 0.16 and 22.99 ± 0.04 and 44 ± 2% 34 ± 1% and 350 ± 15.28 and 210 ± 10 mPa.s, respectively. The yield, swelling power, amylose content, paste clarity, and viscosity of yam starch were significantly higher ( p < 0.05) than from cocoyam starch. The result of FTIR spectroscopy of yam and cocoyam starches at OH stretch was 3176.45 and 3251.60 cm −1 , respectively. At OH stretch cocoyam starch gives higher absorption intensity and broader shape than yam starch, which could be attributed to higher crystallinity of cocoyam starch granules compared to yam starch. The optical and scanning electron microscopy indicated that the granular shape of yam starch was oval whereas cocoyam starch was polygonal with fissures and cavities. In conclusion, from the various functional and structural properties of yam and cocoyam starches evaluated, both could be a cheap and good sources starch, which could be worked for industrial application.

Effect of phosphoric acid treatment on physicochemical, functional, and structural properties of starch extracted from yam ( Dioscorea rotundata )