Saffie N.-E.,Institute for Research in Molecular Medicine INFORMM |
Abdullah J.,Institute for Research in Molecular Medicine INFORMM |
Rahman Z.A.,Universiti Sains Malaysia |
Hussin A.,Hospital Raja Perempuan Zainab II |
And 2 more authors.
Journal of Food Safety | Year: 2014
An in-house loop-mediated isothermal amplification (LAMP) method was established for the detection of Salmonella Typhi and Salmonella Paratyphi A using primers that were designed based on gene coding for putative regulatory protein in S.Typhi (STY4220) and S.Paratyphi A (SSPA3213). This established in-house LAMP assay gave positive results to all the 14 S.Typhi and 20 S.Paratyphi A isolates used in this study and negative to 20 other Salmonella and 19 non-Salmonella bacteria. When tested on 60 clinical samples, it gave positive results to 10 clinical samples containing either S.Typhi or S.Paratyphi A and negative to the other 50 samples, which were similar to those results obtained by gold standard culture method. Because of its rapidity and simplicity, this LAMP offers a promising method for the detection of both S.Typhi and S.Paratyphi A for screening purposes at resource-limited settings. © 2014 Wiley Periodicals, Inc.
Mohamad Nor N.,Universiti Sains Malaysia |
Abdul Razak K.,Universiti Sains Malaysia |
Abdul Razak K.,Institute for Research in Molecular Medicine INFORMM |
Tan S.C.,Institute for Research in Molecular Medicine INFORMM |
Noordin R.,Institute for Research in Molecular Medicine INFORMM
Journal of Alloys and Compounds | Year: 2012
In this study, colloidal stability of iron oxide nanoparticles (IONPs) with several acid functionalizations and biocompatible polymer coating were compared for use as labelling agent in lateral flow immunoassay (LFIA). IONPs were synthesized using the precipitation method and peptized using perchloric acid (PA), nitric acid (NA) and citric acid (CA) to form a stable IONPs ferrofluid. Steric stabilization of IONPs using silane polyethelene glycol (SiPEG) was developed to improve biocompatibility and provide spaces for subsequent conjugation process. From the transmission electron microscopy (TEM) images, the sizes of IONPs obtained with different acids peptization were in range of 11-17 nm. The IONPs peptized using citric acid showed the most stable ferrofluid condition at physiological condition with zeta potential value of -49 mV. The LFIA was also developed to examine the conjugation properties of IONPs to mouse anti-human IgG 4 antibody (MαHIgG 4). IONPs functionalized with citric acid can be directly conjugated with the MαHIgG 4 without the need of SiPEG addition. This is due to the presence of the carboxylic group that acted as a ligand to the extended bond formation with the antibody. Moreover, the conjugation of IONPs with MαHIgG 4 was also tested in a LFIA to detect brugian filariasis. The conjugated IONPs-CA without SIPEG showed the optimum detection efficiency within 15 min of assay time. © 2012 Elsevier B.V. All rights reserved.
Lee M.J.,Institute for Research in Molecular Medicine INFORMM |
Ramanathan S.,Universiti Sains Malaysia |
Ismail R.,Institute for Research in Molecular Medicine INFORMM |
Mansor S.M.,Universiti Sains Malaysia |
And 2 more authors.
Asian Pacific Journal of Tropical Disease | Year: 2014
Introduction: Stability tests are used to evaluate whether an assay is suitable for general laboratory use. All reagents undergo degradation at a defined rate determined by the laws of chemistry and physics. In this assay, stability of antibodies against mitragynine, horseradish peroxidase labeled with mitragynine, and standard calibrators of mitragynine were examined. Objective: To examine the stability of enzyme immunoassay reagents of mitragynine. Methods: For stability test on antibodies and horseradish peroxidase, four types of stabilizers were used and compared with a control. The stabilizers include HRP SELECT, HRP STABILZYME, HRP STABILGUARD, and HRP F1H (In-house). Stability test on standard calibrators of mitragynine was performed without adding any stabilizers. The reagents to be tested were kept at 4°C and 37°C respectively for a period of 10 weeks. The ELISA assay was performed on day 0, 1, 3, 5, 7, 14, 21, 28, 35, 42, 49, 56, 63, and 70 by using the reagents that were kept at 4°C and 37°C respectively. The results obtained were recorded and the respective graphs were plotted. Results & Discussion: For stability tests on antibodies against mitragynine and horseradish peroxidase labeled with mitragynine, the results showed that both were stable either by using HRP STABILZYME, HRP SELECT, HRP STABILGUARD or HRP F1H (In-house) at 4°C and 37°C compared with control, for up to 10 weeks. Using an accepted extrapolation formula, stability for 10 weeks at 37°C translates to 25 months at 4°C. Stability on standard calibrators showed that degradation occurred after one week being stored at 4°C in buffer solution. The readings decreased tremendously when kept in buffer solution at 37°C on day 1 compared with day 0. Conclusion: HRP STABILZYME, HRP SELECT, HRP STABILGUARD and HRP F1H (In-house) can be used as stabilizers for antibodies against mitragynine and horseradish peroxidase labeled with mitragynine. In addition, the standard calibrators of mitragynine were only stable at 4°C for one week in buffer solution. © 2014 Asian Pacific Tropical Medicine Press.