Acrylamide optical sensor based on hydrolysis using Bacillus sp. strain ZK34 containing amidase properties

In this work, a new optical screening method for acrylamide was developed. Bacterial Bacillus sp. strain ZK 34 was used to hydrolyse acrylamide to the corresponding acid and ammonia. Nessler’s reagent was used to detect the produced ammonia and the yellow complex formed was treated as signal. Bacterial pellet was immobilised in the alginate membrane. The optimum composition of alginate used is 2%. The mass ratio of alginate:bacterial of 1:0.5 gave the optimum respond. Optimum concentration for NaOH and Nessler’s reagent were 0.075 M and 2.5 mM, respectively. The yellow complex of mercury (II) amido-iodine formed was directly proportional to the concentrations of acrylamide up to 50.00 ppm with the limit of detection of 1.30 ppm. This sensor shows a good reproducibility which the relatives standard deviation (RSD) values from 3.17-6.15%. Therefore, the detection of acrylamide based on the amidase hydrolysis is suitable for screening this carcinogen compound

Automatic diagnosis of tuberculosis disease based on Plasmonic ELISA and color-based image classification

Tuberculosis (TB) remains one of the most devastating infectious diseases and its treatment efficiency is majorly influenced by the stage at which infection with the TB bacterium is diagnosed. The available methods for TB diagnosis are either time consuming, costly or not efficient. This study employs a signal generation mechanism for biosensing, known as Plasmonic ELISA, and computational intelligence to facilitate automatic diagnosis of TB. Plasmonic ELISA enables the detection of a few molecules of analyte by the incorporation of smart nanomaterials for better sensitivity of the developed detection system. The computational system uses k-means clustering and thresholding for image segmentation. This paper presents the results of the classification performance of the Plasmonic ELISA imaging data by using various types of classifiers. The five-fold cross-validation results show high accuracy rate (>97%) in classifying TB images using the entire data set. Future work will focus on developing an intelligent mobile-enabled expert system to diagnose TB in real-time. The intelligent system will be clinically validated and tested in collaboration with healthcare providers in Malaysia

Lateral flow immunoassay for naked eye detection of Mycobacterium tuberculosis

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. Detection and control of infectious diseases is a major problem, especially in developing countries. Lateral flow immunoassay (LFIA) has been introduced as a handheld immunoassay-based point-of-care platform for an automated detection of TB. The CFP10-ESAT6 antigen of M. tuberculosis was used as the target in early detection of TB using LFIA strip-based POC strategy. An interesting platform based on optical signals is implemented as a colour change in the detection area that is visible to the naked eye. The gold nanoparticles (AuNPs) were used as the colour probe for the detection of a target of interest. The high-resolution transmission electron microscopy (HRTEM) image and ultraviolet-visible spectrophotometer (UV-Vis) analysis confirmed that the synthesized AuNPs were appropriate for the immunoassay designed. The platform consists of AuNPs conjugated with specific antibodies (Ab) to capture the antigen of M. tuberculosis. Under the capillary effect, sandwich immunoreactions of AuNP-Ab-antigen were performed on the test pad of the immunostrip, which can be observed by the colour signal on the test line of the strip with a short assay time. Furthermore, the newly developed biosensor was utilized in CFP10-ESAT6 antigen detection in human sputum specimens with satisfactory results. The characteristic coloured bands enable visual detection (naked eye) of target analyte without instrumentation. This noninvasive diagnose system which is sputum-based detection could provide user-friendly and affordable diagnostic tests in developing countries

Automatic diagnosis of tuberculosis disease based on plasmonic ELISA and color-based image classification

Tuberculosis (TB) remains one of the most devastating infectious diseases and its treatment efficiency is majorly influenced by the stage at which infection with the TB bacterium is diagnosed. The available methods for TB diagnosis are either time consuming, costly or not efficient. This study employs a signal generation mechanism for biosensing, known as Plasmonic ELISA, and computational intelligence to facilitate automatic diagnosis of TB. Plasmonic ELISA enables the detection of a few molecules of analyte by the incorporation of smart nanomaterials for better sensitivity of the developed detection system. The computational system uses k-means clustering and thresholding for image segmentation. This paper presents the results of the classification performance of the Plasmonic ELISA imaging data by using various types of classifiers. The five-fold cross-validation results show high accuracy rate (>97%) in classifying TB images using the entire data set. Future work will focus on developing an intelligent mobile-enabled expert system to diagnose TB in real-time. The intelligent system will be clinically validated and tested in collaboration with healthcare providers in Malaysia

Biodegradation of acrylamide by a newly isolated Bacillus sp. strain ZK34

Acrylamide is a toxic and carcinogenic compound which may cause cancer and genetic mutation, and also irritation to the skin and respiratory tract. The main sources of acrylamide pollution are the release of monomer residues from polyacrylamide which are widely used for water treatment and from the formulation of herbicide glyphosate. To overcome this problem, a potent and efficient acrylamide-degrading bacterium has been isolated from agricultural soil. The isolate was tentatively identified as Bacillus sp. strain ZK34 based on 16S rRNA molecular phylogeny and was deposited at the GenBank under the accession number KC433533. Bacillus sp. strain ZK34 grew optimally in the range of pH 7.0 and pH 8.0, and at 28°C. The test on effects of carbon sources on the growth of the bacterium was carried out using carbon sources such as glucose, sucrose, fructose, lactose, maltose, mannitol, citric acid, dextrin and glycerol at the initial concentration of 1.0% (w/v) with acrylamide as the sole nitrogen source. The results showed that glucose was the best carbon source for bacterium growth. The effects of different aliphatic amides on the growth of strain ZK34 using 1.0% (w/v) glucose as the carbon source showed that acrylamide, propionamide, methacrylamide,nicotinamide, and acetamide supported growth with increasing assimilative capability from methacrylamide to propionamide while 2-loroacetamide did not support growth. The optimum concentration of acrylamide for the growth of Bacillus sp. strain ZK34 was at 0.5 g/L. Bacillus sp. strain ZK34 could degrade 0.5 g/L of acrylamide in three days of incubation with concomitant cell growth. Strain ZK34 was immobilized in gellan gum and the degradation of acrylamide was compared between freely-suspended and immobilized cells. Optimization for immobilization procedures found 0.75% (w/v) of gellan gum, 300 beads/100 mL of BSM and 3 mm of bead size gave optimum degradation of acrylamide. Bacillus sp. strain ZK34 which has been immobilized in gellan gum beads showed enhanced degradation of elevated concentrations of acrylamide (3.0 g/L) compared to the free cells (2.0 g/L) and could be reused for at least 8 complete cycles. Kinetics study revealed that immobilized cells suited Yano model which indicated the acrylamide was not toxic to the cells even though the acrylamide concentration was high, while free cells fitted to Luong kinetic model where acrylamide was toxic whether at low or high concentrations. Heavy metals and pesticides showed less inhibition of acrylamide degradation in immobilized cells than the free cells. The outcome of this study will contribute to additional knowledge on a new source of more efficient microbe in acrylamide degrading process and has high potential to be used in the contaminated sites

Lateral flow immunoassay for ultrasensitive and affordable naked eye detection of tuberculosis

Lateral flow immunoassays (LFIAs) are advantageous over conventional detection methods in terms of their simplicity and rapidity. These assays have been reported using various types of labels but colloidal gold nanoparticles are still the preferred choice as a label because of their easy synthesis, visual detection and stability. Tuberculosis, or TB, is an infectious bacterial disease caused by Mycobacterium tuberculosis. İt remains one of the deadliest diseases in the world. The detection of Mycobacterium tuberculosis using LFIAs was developed and analyzed using gold nanoparticle

Electrochemical immunosensor for detection of Mycobacterium tuberculosis

A rapid and sensitive sandwich electrochemical immunosensor was developed based on the fabrication of the graphene/polyaniline (GP/PANI) nanocomposite onto screen-printed gold electrode (SPGE) for detection of Mycobacterium tuberculosis (M. tuberculosis) antigen. The chemical bonding and morphology of GP/PANI-modified SPGE were studied by Raman spectroscopy and field enhance scanning electron microscopy-energy dispersive X-ray spectroscopy (FESEM-EDX), respectively. From both studies, it clearly showed that GP/PANI was successfully coated onto SPGE through drop cast technique. Cyclic voltammetry (CV) was used to study the electrochemical properties of the modified electrode. The effective surface area for GP/PANI-modified SPGE was enhanced when compared with bare SPGE. Differential pulse voltammetry (DPV) was used to detect the M. tuberculosis antigen. This proposed electrochemical immunosensor is sensitive, low sample volume, rapid, and disposable, which is suitable for tuberculosis detection in real samples

Sandwich Electrochemical Immunosensor for Early Detection of Tuberculosis Based on Graphene/Polyaniline-Modified Screen-Printed Gold Electrode

A rapid and sensitive sandwich electrochemical immunosensor was developed based on the fabrication of the graphene/polyaniline (GP/PANI) nanocomposite onto screen-printed gold electrode (SPGE) for detection of tuberculosis biomarker 10-kDa culture filtrate protein (CFP10). The prepared GP/PANI nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The chemical bonding and morphology of GP/PANI-modified SPGE were studied by Raman spectroscopy and FESEM coupled with energy dispersive X-ray spectroscopy, respectively. From both studies, it clearly showed that GP/PANI was successfully coated onto SPGE through drop cast technique. Cyclic voltammetry was used to study the electrochemical properties of the modified electrode. The effective surface area for GP/PANI-modified SPGE was enhanced about five times compared with bare SPGE. Differential pulse voltammetry was used to detect the CFP10 antigen. The GP/PANI-modified SPGE that was fortified with sandwich type immunosensor exhibited a wide linear range (20⁻100 ng/mL) with a low detection limit of 15 ng/mL. This proposed electrochemical immunosensor is sensitive, low sample volume, rapid and disposable, which is suitable for tuberculosis detection in real samples

Enhanced Electrochemical Conductivity of Surface-Coated Gold Nanoparticles/Copper Nanowires onto Screen-Printed Gold Electrode

Electrochemical application has been widely used in the study of biosensors. Small biomolecules need a sensitive sensor, as the transducer that can relay the signal produced by biomolecule interactions. Therefore, we are improvising a sensor electrode to enhance electrochemical conductivity for the detection of small DNA molecule interaction. This work describes the enhanced electrochemical conductivity studies of copper nanowires/gold nanoparticles (CuNWs/AuNPs), using the screen-printed gold electrode (SPGE). The AuNPs were synthesized using the Turkevich method as well as characterized by the high-resolution transmission electron microscopy (HRTEM) and ultraviolet-visible (UV-Vis) analysis for the particle size and absorption nature, respectively. Further, the surface morphology and elemental analysis of a series of combinations of different ratios of CuNWs-AuNPs-modified SPGE were analyzed by field emission scanning electron microscopy (FESEM) combined with an energy dispersive X-ray (EDX). The results indicate that the nanocomposites of CuNWs-AuNPs have been randomly distributed and compacted on the surface of SPGE, with AuNPs filling the pores of CuNWs, thereby enhancing its electrochemical conductivity. The cyclic voltammetry (CV) method was used for the evaluation of SPGE performance, while the characterization of the electrochemical conductivity of the electrode modified with various concentrations of AuNPs, CuNWs, and different volumes of dithiopropionic acid (DTPA) has been conducted. Of the various parameters tested, the SPGE modified with a mixture of 5 mg/mL CuNWs and 0.25 mM AuNPs exhibited an efficient electrochemical conductivity of 20.3 µA. The effective surface area for the CuNWs-AuNPs-modified SPGE was enhanced by 2.3-fold compared with the unmodified SPGE, thereby conforming the presence of a large active biomolecule interaction area and enhanced electrochemical activity on the electrode surface, thus make it promising for biosensor application

Enhanced electrochemical conductivity of surface-coated gold nanoparticles/copper nanowires onto screen-printed gold electrode

Electrochemical application has been widely used in the study of biosensors. Small biomolecules need a sensitive sensor, as the transducer that can relay the signal produced by biomolecule interactions. Therefore, we are improvising a sensor electrode to enhance electrochemical conductivity for the detection of small DNA molecule interaction. This work describes the enhanced electrochemical conductivity studies of copper nanowires/gold nanoparticles (CuNWs/AuNPs), using the screen-printed gold electrode (SPGE). The AuNPs were synthesized using the Turkevich method as well as characterized by the high-resolution transmission electron microscopy (HRTEM) and ultraviolet-visible (UV-Vis) analysis for the particle size and absorption nature, respectively. Further, the surface morphology and elemental analysis of a series of combinations of different ratios of CuNWs-AuNPs-modified SPGE were analyzed by field emission scanning electron microscopy (FESEM) combined with an energy dispersive X-ray (EDX). The results indicate that the nanocomposites of CuNWs-AuNPs have been randomly distributed and compacted on the surface of SPGE, with AuNPs filling the pores of CuNWs, thereby enhancing its electrochemical conductivity. The cyclic voltammetry (CV) method was used for the evaluation of SPGE performance, while the characterization of the electrochemical conductivity of the electrode modified with various concentrations of AuNPs, CuNWs, and different volumes of dithiopropionic acid (DTPA) has been conducted. Of the various parameters tested, the SPGE modified with a mixture of 5 mg/mL CuNWs and 0.25 mM AuNPs exhibited an efficient electrochemical conductivity of 20.3 µA. The effective surface area for the CuNWs-AuNPs-modified SPGE was enhanced by 2.3-fold compared with the unmodified SPGE, thereby conforming the presence of a large active biomolecule interaction area and enhanced electrochemical activity on the electrode surface, thus make it promising for biosensor application