Ultrasensitive dual probe immunosensor for the monitoring of nicotine induced-brain derived neurotrophic factor released from cancer cells

Akhtar, Mahmood H.,Hussain, Khalil K.,Gurudatt, N.G.,Chandra, Pranjal,Shim, Yoon-Bo Elsevier 2018 Biosensors & bioelectronics Vol.116 No.-

<P><B>Abstract</B></P> <P>Brain-derived neurotrophic factor (BDNF) was detected in the extracellular matrix of neuronal cells using a dual probe immunosensor (DPI), where one of them was used as a working and another bioconjugate loading probe. The working probe was fabricated by covalently immobilizing capture anti-BDNF (Cap Ab) on the gold nanoparticles (AuNPs)/conducting polymer composite layer. The bioconjugate probe was modified by drop casting a bioconjugate particles composed of conducting polymer self-assembled AuNPs, immobilized with detection anti-BDNF (Det Ab) and toluidine blue O (TBO). Each sensor layer was characterized using the surface analysis and electrochemical methods. Two modified probes were precisely faced each other to form a microfluidic channel structure and the gap between inside modified surfaces was about 19 µm. At optimized conditions, the DPI showed a linear dynamic range from 4.0 to 600.0 pg/ml with a detection limit of 1.5 ± 0.012 pg/ml. Interference effect of IgG, arginine, glutamine, serine, albumin, and fibrinogene were examined and stability of the developed biosensor was also investigated. The reliability of the DPI sensor was evaluated by monitoring the extracellular release of BDNF using exogenic activators (ethanol, K<SUP>+</SUP>, and nicotine) in neuronal and non-neuronal cells. In addition, the effect of nicotine onto neuroblastoma cancer cells (SH-SY5Y) was studied in detail.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This work reports for the first time a dual probe immunosensor for BDNF. </LI> <LI> Bioconjugate particles were synthesized, which composed of anti-BDNF and TBO chemically bonded onto the SAM. </LI> <LI> The proposed method can be extended for <I>in-vivo</I> applications, which is a unique feature of this immunosensor. </LI> <LI> In biological matrix, nicotine-induced BDNF release in neuroblastoma cancer cells was monitored. </LI> </UL> </P>

Analysis of Diffraction Gratings Embedded in Inhomogeneous and Lossy Dielectric

Mahmood K. Moaveni,Azhar A. Rizvi,Bahman A. Kamran 대한전자공학회 1997 TENCON 87 - Computers and Communications Technolog Vol.- No.-

Rician noise reduction in magnetic resonance images using adaptive non-local mean and guided image filtering

Mahmood, M. T.,Chu, Y. H.,Choi, Y. K. Springer Science + Business Media 2016 Optical review Vol.23 No.3

<P>This paper proposes a Rician noise reduction method for magnetic resonance (MR) images. The proposed method is based on adaptive non-local mean and guided image filtering techniques. In the first phase, a guidance image is obtained from the noisy image through an adaptive non-local mean filter. Sobel operators are applied to compute the strength of edges which is further used to control the spread of the kernel in non-local mean filtering. In the second phase, the noisy and the guidance images are provided to the guided image filter as input to restore the noise-free image. The improved performance of the proposed method is investigated using the simulated and real data sets of MR images. Its performance is also compared with the previously proposed state-of-the art methods. Comparative analysis demonstrates the superiority of the proposed scheme over the existing approaches.</P>

Two cases of cholera O1 in South Batinah, Oman, April 2019: lessons learned

Zayid K. Al Mayahi,Nasser Al-Shaqsi,Hamid A. Elmutashi,Ali Al-Dhoyani,Azza Al Hattali,Khalid Salim,Issa S. Al Fulaiti,Mahmood S. Al Subhi 한국역학회 2019 Epidemiology and Health Vol.41 No.-

Cholera represents an ongoing threat to many low-income and middle-income countries, but some cases of cholera even occur in high-income countries. Therefore, to prevent or combat cholera outbreaks, it is necessary to maintain the capacity to rapidly detect cholera cases, implement infection control measures, and improve general hygiene in terms of the environment, water, and food. The 2 cases, 1 imported and 1 secondary, described herein are broadly indicative of areas that require improvement. These cases were missed at the primary health care stage, which should be the first detection point even for unusual diseases such as cholera, and the absence of strict infection control practices at the primary care level is believed to contribute to secondary cases of infection. This report also encourages countries to ensure that rapid diagnostic stool tests are available to enable quick detection, as well as to provide information to people travelling to areas where cholera is endemic.

Detection of Ca²⁺-induced acetylcholine released from leukemic T-cells using an amperometric microfluidic sensor

Akhtar, Mahmood H.,Hussain, Khalil K.,Gurudatt, N.G.,Shim, Yoon-Bo Elsevier Applied Science 2017 Biosensors & Bioelectronics Vol. No.

<P><B>Abstract</B></P> <P>A microfluidic structured-dual electrodes sensor comprising of a pair of screen printed carbon electrodes was fabricated to detect acetylcholine, where one of them was used for an enzyme reaction and another for a detection electrode. The former was coated with gold nanoparticles and the latter with a porous gold layer, followed by electropolymerization of 2, 2:5,2-terthiophene-3-(p-benzoic acid) (pTTBA) on both the electrodes. Then, acetylcholinesterase was covalently attached onto the reaction electrode, and hydrazine and choline oxidase were co-immobilized on the detection electrode. The layers of both modified electrodes were characterized employing voltammetry, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and quartz crystal microscopy. After the modifications of both electrode surfaces, they were precisely faced each other to form a microfluidic channel structure, where H<SUB>2</SUB>O<SUB>2</SUB> produced from the sequential enzymatic reactions was reduced by hydrazine to obtain the analytical signal which was analyzed by the detection electrode. The microfluidic sensor at the optimized experimental conditions exhibited a wide dynamic range from 0.7nM to 1500μM with the detection limit of 0.6 ± 0.1nM based on 3s (S/N = 3). The biomedical application of the proposed sensor was evaluated by detecting acetylcholine in human plasma samples. Moreover, the Ca<SUP>2+</SUP>-induced acetylcholine released in leukemic T-cells was also investigated to show the <I>in vitro</I> detection ability of the designed microfluidic sensor. Interference due to the real component matrix were also studied and long term stability of the designed sensor was evaluated. The analytical performance of the designed sensor was also compared with commercially available ACh detection kit.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A microfluidic structured-dual electrodes sensor comprising of a pair of SPCE. </LI> <LI> Covalent attachment of AChE on reaction and ChoX and hydrazine on detection electrode. </LI> <LI> Sequential enzymatic reactions produced H<SUB>2</SUB>O<SUB>2</SUB>, which reduced by hydrazine. </LI> <LI> Nifedipine effect was monitored in Ca<SUP>2+</SUP>-induced ACh release in leukemic T-cells. </LI> </UL> </P>

Performance comparison between multienzymes loaded single and dual electrodes for the simultaneous electrochemical detection of adenosine and metabolites in cancerous cells

Hussain, Khalil K.,Akhtar, Mahmood H.,Kim, Moo-Hyun,Jung, Dong-Keun,Shim, Yoon-Bo Elsevier Applied Science 2018 Biosensors & bioelectronics Vol. No.

<P><B>Abstract</B></P> <P>The analytical performance of the multi enzymes loaded single electrode sensor (SES) and dual electrode sensor (DES) was compared for the detection of adenosine and metabolites. The SES was fabricated by covalent binding of tri-enzymes, adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), and xanthine oxidase (XO) along with hydrazine (Hyd) onto a functionalized conducting polymer [2,2:5,2-terthiophene-3-(p-benzoic acid)] (pTTBA). The enzyme reaction electrode in DES was fabricated by covalent binding of ADA and PNP onto pTTBA coated on Au nanoparticles. The detection electrode in DES was constructed by covalent binding of XO and Hyd onto pTTBA coated on porous Au. Due to the higher amount (3.5 folds) of the immobilized enzymes and Hyd onto the DES than SES, and the lower Michaelis constant (Km) value for DES (28.7 µM) compared to SES (36.1 µM), the sensitivity was significantly enhanced for the DES (8.2 folds). The dynamic range obtained using DES was from 0.5 nM to 120.0 µM with a detection limit of 1.43 nM ± 0.02, 0.76 nM ± 0.02, and 0.48 nM ± 0.01, for adenosine (AD), inosine (IN), and hypoxanthine (Hypo) respectively. Further, the DES was coupled with an electrochemical potential modulated microchannel for the separation and simultaneous detection of AD, IN, and Hypo in an extracellular matrix of cancerous (A549) and non-cancerous (Vero) cells. The sensor probe confirms a higher basal level of extracellular AD and its metabolites in cancer cells compared to normal cells. In addition, the effect of dipyridamole on released adenosine in A549 cells was investigated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Performance comparison between multienzymes loaded single and dual electrodes sensor. </LI> <LI> Electrochemical potential modulated microchannel (EPMM) coupled with dual electrode sensor (DES). </LI> <LI> Electrochemical separation analysis of adenosine, inosine, and hypoxanthine in extracellular cancer cells. </LI> <LI> Adenosine concentration was monitored with and without an adenosine reuptake inhibitor (dipyridamole) in A549 and Vero cells. </LI> </UL> </P>

Accuracy of FDG-PET/CT for Detection of Incidental Pre-Malignant and Malignant Colonic Lesions - Correlation with Colonoscopic and Histopathologic Findings

Kunawudhi, Anchisa,Wong, Alexandra K,Alkasab, Tarik K,Mahmood, Umar Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.8

Purpose: We evaluated all PET/CTs acquired for patients without a primary diagnosis of colorectal cancer, and compared results for those who had subsequent colonoscopy within 6 months, to assess the accuracy of FDG PET/CT for detection of incidental pre-malignant polyps and malignant colon cancers. Materials and Methods: Medical records of 9,545 patients who underwent F-18 FDG PET/CT studies over 3.5 years were retrospectively reviewed. Due to pre-existing diagnosis of colorectal cancer, 818 patients were excluded. Of the remainder, 157 patients had colonoscopy within 6 months (79 males; mean age 61). We divided the colon into 4 regions and compared PET/CT results for each region with colonoscopy and histopathologic findings. True positive lesions included colorectal cancer, villous adenoma, tubulovillous adenoma, tubular adenoma and serrated hyperplastic polyp/hyperplastic polyposis. Results: Of 157 patients, 44 had incidental colonic uptake on PET/CT (28%). Of those, 25 had true positive (TP) uptake, yielding a 48% positive predictive value (PPV); 9% (4/44) were adenocarcinoma. There were 23 false positive (FP) lesions of which 4 were hyperplastic polyp, one was juvenile polyp and 7 were explained by diverticulitis. Fifty eight patients had false negative PET scans but colonoscopy revealed true pre-malignant and malignant pathology, yielding 23% sensitivity. The specificity, negiative predictive value (NPV) and accuracy were 96%, 90% and 87%, respectively. The average SUVmax values of TP, FP and FN lesions were 7.25, 6.11 and 2.76, respectively. There were no significant difference between SUVmax of TP lesions and FP lesions (p>0.95) but significantly higher than in FN lesions (p<0.001). The average size (by histopathology and colonoscopy) of TP lesions was 18.1 mm, statistically different from that of FN lesions which was 5.9 mm (p<0.001). Fifty-one percent of FN lesions were smaller than 5 mm (29/57) and 88% smaller than 10 mm (50/57). Conclusions: The high positive predictive value of incidental focal colonic FDG uptake of 48% for colonic neoplasia suggests that colonoscopy follow-up is warranted with this finding. We observed a low sensitivity of standardly acquired FDG-PET/CT for detecting small polyps, especially those less than 5 mm. Clinician and radiologists should be aware of the high PPV of focal colonic uptake reflecting pre-malignant and malignant lesions, and the need for appropriate follow up.

Particle distribution in melt-processed Y_1.5 Ba₂Cu₃O_x superconductors with BaCeO₃ addition

Youn, J.S.,No, K.,Kim, Y.H.,Mahmood, A.,Jun, B.H.,Han, Y.H.,Sung, T.H.,Kim, C.J. North-Holland 2009 Physica. C, Superconductivity Vol.469 No.15

To understand the effect of BaCeO<SUB>3</SUB> on a Y<SUB>2</SUB>BaCuO<SUB>5</SUB> (Y211) distribution, Y<SUB>1.5</SUB>Ba<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>x</SUB> (Y1.5) superconductors with/without 1wt.% BaCeO<SUB>3</SUB> additions were prepared by a top-seeded melt-textured growth (TSMG) process. Two different BaCeO<SUB>3</SUB> powders (as-synthesized (coarse powder) and an attrition-milled (fine powder)) were used and the size effect was compared with that obtained from a Y1.5 sample with no addition. A refinement of the Y211 particles was achieved for both the as-synthesized and attrition-milled BaCeO<SUB>3</SUB> additions. The distribution of the Y211 particles was most uniform in the Y1.5 sample prepared with the attrition-milled BaCeO<SUB>3</SUB> powder due to the reduced size of the Y211-free regions by the fine size BaCeO<SUB>3</SUB> addition. The highest J<SUB>c</SUB> was achieved in the Y1.5 sample prepared with the attrition-milled BaCeO<SUB>3</SUB> powder. The J<SUB>c</SUB> result agreed well with the microstructure variations by the addition of BaCeO<SUB>3</SUB> powders.

Preparation of Cu₂ZnSnS₄ thin films by using electrospray method: Experimental and modeling approach on film growth

Song, D.,Kim, W.,Mahmood, K.,Kang, H.W.,Park, S.B.,Park, S.,Han, J.I. Elsevier Sequoia 2013 JOURNAL OF ALLOYS AND COMPOUNDS Vol.567 No.-

Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> (CZTS) thin films were deposited on glass substrate by using an electrospray method and an annealing process for improving the crystallinity and the morphology of the prepared films was performed. To investigate the relationship between the volume of a droplet on the substrate and the area of the deposited film, a numerical study on the wetting properties was performed for the first time in electrospray research, so a mathematical model to predict the shape of the droplet on the substrate with respect to temperature was developed. According to the simulation results, the deposition area by the single droplet was accurately predicted compared with the experimental data. In addition to the numerical approach, the properties of the films were experimentally analyzed. Consequently, the film with the best crystallinity, was synthesized by 60min electrospraying deposition and followed by the annealing at 663K. This film showed an optical band gap of 1.55eV. Thus, both experimental and modeling analysis will suggest a new process to produce inorganic thin films.

Fabrication of CeO₂ Cap Layer on Coated Conductor by Electron Beam Evaporation

J.B. Lee,S.K. Park,H.J. Kim,B.J. Kim,S.K. Hong,S.H. Moon,A. Mahmood,H.G. Lee,G.W. Hong 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12