Displaying publications 21 - 40 of 337 in total

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  1. Fulltext Magnetic nanoparticles assisted dispersive liquid-liquid microextraction of chloramphenicol in water samples
    Saad SM, Aling NA, Miskam M, Saaid M, Mohamad Zain NN, Kamaruzaman S, et al.
    R Soc Open Sci, 2020 Apr;7(4):200143.
    PMID: 32431904 DOI: 10.1098/rsos.200143
    This work describes the development of a new methodology based on magnetic nanoparticles assisted dispersive liquid-liquid microextraction (DLLME-MNPs) for preconcentration and extraction of chloramphenicol (CAP) antibiotic residues in water. The approach is based on the use of decanoic acid as the extraction solvent followed by the application of MNPs to magnetically retrieve the extraction solvent containing the extracted CAP. The coated MNPs were then desorbed with methanol, and the clean extract was analysed using ultraviolet-visible spectrophotometry. Several important parameters, such as the amount of decanoic acid, extraction time, stirring rate, amount of MNPs, type of desorption solvent, salt addition and sample pH, were evaluated and optimized. Optimum parameters were as follows: amount of decanoic acid: 200 mg; extraction time: 10 min; stirring rate: 800 rpm; amount of MNPs: 60 mg; desorption solvent: methanol; salt: 10%; and sample pH, 8. Under the optimum conditions, the method demonstrated acceptable linearity (R2 = 0.9933) over a concentration range of 50-1000 µg l-1. Limit of detection and limit of quantification were 16.5 and 50.0 µg l-1, respectively. Good analyte recovery (91-92.7%) and acceptable precision with good relative standard deviations (0.45-6.29%, n = 3) were obtained. The method was successfully applied to tap water and lake water samples. The proposed method is rapid, simple, reliable and environmentally friendly for the detection of CAP.
    Matched MeSH terms: Limit of Detection
  2. An efficient biosorption-based dispersive liquid-liquid microextraction with extractant removal by magnetic nanoparticles for quantification of bisphenol A in water samples by gas chromatography-mass spectrometry detection
    Subuhi NEAM, Saad SM, Zain NNM, Lim V, Miskam M, Kamaruzaman S, et al.
    J Sep Sci, 2020 Aug;43(16):3294-3303.
    PMID: 32519432 DOI: 10.1002/jssc.201901194
    In this work, a simple, fast, sensitive, and environmentally friendly method was developed for preconcentration and quantitative measurement of bisphenol A in water samples using gas chromatography with mass spectrometry. The preconcentration approach, namely biosorption-based dispersive liquid-liquid microextraction with extractant removal by magnetic nanoparticles was performed based on the formation of microdroplet of rhamnolipid biosurfactant throughout the aqueous samples, which accelerates the mass transfer process between the extraction solvent and sample solution. The process is then followed by the application of magnetic nanoparticles for easy retrieval of the analyte-containing extraction solvent. Several important variables were optimized comprehensively including type of disperser solvent and desorption solvent, rhamnolipid concentration, volume of disperser solvent, amount of magnetic nanoparticles, extraction time, desorption time, ionic strength, and sample pH. Under the optimized microextraction and gas chromatography with mass spectrometry conditions, the method demonstrated good linearity over the range of 0.5-500 µg/L with a coefficient of determination of R2  = 0.9904, low limit of detection (0.15 µg/L) and limit of quantification (0.50 µg/L) of bisphenol A, good analyte recoveries (84-120%) and acceptable relative standard deviation (1.8-14.9%, n = 6). The proposed method was successfully applied to three environmental water samples, and bisphenol A was detected in all samples.
    Matched MeSH terms: Limit of Detection
  3. MCM-41 solid phase membrane tip extraction combined with liquid chromatography for the determination of non-steroidal anti-inflammatory drugs in human urine
    Kamaruzaman S, Sanagi MM, Endud S, Wan Ibrahim WA, Yahaya N
    J Chromatogr B Analyt Technol Biomed Life Sci, 2013 Dec 1;940:59-65.
    PMID: 24140656 DOI: 10.1016/j.jchromb.2013.09.017
    Mesoporous silica material, MCM-41, was utilized for the first time as an adsorbent in solid phase membrane tip extraction (SPMTE) of non-steroidal anti-inflammatory drugs (NSAIDs) in urine prior to high performance liquid chromatography-ultraviolet (HPLC-UV) analysis. The prepared MCM-41 material was enclosed in a polypropylene membrane tip and used as an adsorbent in SPMTE. Four NSAIDs namely ketoprofen, diclofenac, mefenamic acid and naproxen were selected as model analytes. Several important parameters, such as conditioning solvent, sample pH, salting-out effect, sample volume, extraction time, desorption solvent and desorption time were optimized. Under the optimum extraction conditions, the MCM-41-SPMTE method showed good linearity in the range of 0.01-10μg/mL with excellent correlation coefficients (r=0.9977-0.9995), acceptable RSDs (0.4-9.4%, n=3), good limits of detection (5.7-10.6μg/L) and relative recoveries (81.4-108.1%). The developed method showed a good tolerance to biological sample matrices.
    Matched MeSH terms: Limit of Detection
  4. Sensitive Leptospira DNA detection using tapered optical fiber sensor
    Zainuddin NH, Chee HY, Ahmad MZ, Mahdi MA, Abu Bakar MH, Yaacob MH
    J Biophotonics, 2018 08;11(8):e201700363.
    PMID: 29570957 DOI: 10.1002/jbio.201700363
    This paper presents the development of tapered optical fiber sensor to detect a specific Leptospira bacteria DNA. The bacteria causes Leptospirosis, a deadly disease but with common early flu-like symptoms. Optical single mode fiber (SMF) of 125 μm diameter is tapered to produce 12 μm waist diameter and 15 cm length. The novel DNA-based optical fiber sensor is functionalized by incubating the tapered region with sodium hydroxide (NaOH), (3-Aminopropyl) triethoxysilane and glutaraldehyde. Probe DNA is immobilized onto the tapered region and subsequently hybridized by its complementary DNA (cDNA). The transmission spectra of the DNA-based optical fiber sensor are measured in the 1500 to 1600 nm wavelength range. It is discovered that the shift of the wavelength in the SMF sensor is linearly proportional with the increase in the cDNA concentrations from 0.1 to 1.0 nM. The sensitivity of the sensor toward DNA is measured to be 1.2862 nm/nM and able to detect as low as 0.1 fM. The sensor indicates high specificity when only minimal shift is detected for non-cDNA testing. The developed sensor is able to distinguish between actual DNA of Leptospira serovars (Canicola and Copenhageni) against Clostridium difficile (control sample) at very low (femtomolar) target concentrations.
    Matched MeSH terms: Limit of Detection*
  5. An integrated lateral flow assay for effective DNA amplification and detection at the point of care
    Choi JR, Hu J, Gong Y, Feng S, Wan Abas WA, Pingguan-Murphy B, et al.
    Analyst, 2016 05 10;141(10):2930-9.
    PMID: 27010033 DOI: 10.1039/c5an02532j
    Lateral flow assays (LFAs) have been extensively explored in nucleic acid testing (NAT) for medical diagnostics, food safety analysis and environmental monitoring. However, the amount of target nucleic acid in a raw sample is usually too low to be directly detected by LFAs, necessitating the process of amplification. Even though cost-effective paper-based amplification techniques have been introduced, they have always been separately performed from LFAs, hence increasing the risk of reagent loss and cross-contaminations. To date, integrating paper-based nucleic acid amplification into colorimetric LFA in a simple, portable and cost-effective manner has not been introduced. Herein, we developed an integrated LFA with the aid of a specially designed handheld battery-powered system for effective amplification and detection of targets in resource-poor settings. Interestingly, using the integrated paper-based loop-mediated isothermal amplification (LAMP)-LFA, we successfully performed highly sensitive and specific target detection, achieving a detection limit of as low as 3 × 10(3) copies of target DNA, which is comparable to the conventional tube-based LAMP-LFA in an unintegrated format. The device may serve in conjunction with a simple paper-based sample preparation to create a fully integrated paper-based sample-to-answer diagnostic device for point-of-care testing (POCT) in the near future.
    Matched MeSH terms: Limit of Detection
  6. Improved sensitivity of lateral flow assay using paper-based sample concentration technique
    Tang R, Yang H, Choi JR, Gong Y, Hu J, Feng S, et al.
    Talanta, 2016 May 15;152:269-76.
    PMID: 26992520 DOI: 10.1016/j.talanta.2016.02.017
    Lateral flow assays (LFAs) hold great promise for point-of-care testing, especially in resource-poor settings. However, the poor sensitivity of LFAs limits their widespread applications. To address this, we developed a novel device by integrating dialysis-based concentration method into LFAs. The device successfully achieved 10-fold signal enhancement in Human Immunodeficiency Virus (HIV) nucleic acid detection with a detection limit of 0.1nM and 4-fold signal enhancement in myoglobin (MYO) detection with a detection limit of 1.56ng/mL in less than 25min. This simple, low-cost and portable integrated device holds great potential for highly sensitive detection of various target analytes for medical diagnostics, food safety analysis and environmental monitoring.
    Matched MeSH terms: Limit of Detection
  7. Sensitive silica-alumina modified capacitive non-Faradaic glucose sensor for gestational diabetes
    Chen L, Xie W, Luo Y, Ding X, Fu B, Gopinath SCB, et al.
    Biotechnol Appl Biochem, 2021 Mar 30.
    PMID: 33786878 DOI: 10.1002/bab.2155
    A highly sensitive silica-alumina (Si-Al)-modified capacitive non-Faradaic glucose biosensor was introduced to monitor gestational diabetes. Glucose oxidase (GOx) was attached to the Si-Al electrode surface as the probe through amine-modification followed by glutaraldehyde premixed GOx as aldehyde-amine chemistry. This Si-Al (∼50 nm) modified electrode surface has increased the current flow upon binding of GOx with glucose. Capacitance values were increased by increasing the glucose concentrations. A mean capacitance value was plotted and the detection limit was found as 0.03 mg/mL with the regression coefficient value, R² = 0.9782 [y = 0.8391x + 1.338] on the linear range between 0.03 and 1 mg/mL. Further, a biofouling experiment with fructose and galactose did not increase the capacitance, indicating the specific glucose detection. This Si-Al-modified capacitance sensor detects a lower level of glucose presence and helps in monitoring gestational diabetes.
    Matched MeSH terms: Limit of Detection
  8. Gold-nanourchin seeded single-walled carbon nanotube on voltammetry sensor for diagnosing neurogenerative Parkinson's disease
    Zhang R, Wang S, Huang X, Yang Y, Fan H, Yang F, et al.
    Anal Chim Acta, 2020 Jan 15;1094:142-150.
    PMID: 31761041 DOI: 10.1016/j.aca.2019.10.012
    α-synuclein is a predominantly expressing neuronal protein for understanding the neurodegenerative disorders. A diagnosing system with aggregated α-synuclein encoded by SNCA gene is necessary to make the precautionary treatment against Parkinson's disease (PD). Herein, gold-nanourchin conjugated anti-α-synuclein antibody was desired as the probe and seeded on single-walled carbon nanotube (SWCN) integrated interdigitated electrode (IDE). The surface morphology of SWCN-modified IDE and gold urchin-antibody conjugates were observed under FESEM, FETEM and AFM, the existing elements were confirmed. Voltammetry analysis revealed that the limit of fibril-formed α-synuclein detection was improved by 1000 folds (1 fM) with gold-nanourchin-antibody modified surface, compared to the surface with only antibody (1 pM). Validating the interaction of α-synuclein by Enzyme-linked Immunosorbent Assay was displayed the detection limit as 10 pM. IDE has a good reproducibility and a higher selectivity on α-synuclein as evidenced by the interactive analysis with the control proteins, PARK1 and DJ-1.
    Matched MeSH terms: Limit of Detection
  9. Quantification of nimetazepam and its metabolite in human hair samples using liquid chromatography-tandem mass spectrometry: Case report
    Dai Y, Han L, Wang Y, Zhao K, Gu J, Bai H, et al.
    Leg Med (Tokyo), 2023 Nov;65:102303.
    PMID: 37598646 DOI: 10.1016/j.legalmed.2023.102303
    Nimetazepam (marketed brand names; Erimin and Lavol) is an intermediate acting benzodiazepine derivative, which was widely used mainly in East and Southeast Asian region countries including Japan, Malaysia, Brunei, the Philippines, Thailand, Indonesia, Hong Kong, Singapore and China. Nimetazepam and its metabolite 7-aminonimetazepam were quantified from human hair samples by liquid chromatography tandem-mass spectrometry (LC-MS/MS), under selective reaction monitoring mode. Using diazepam-d5 as an internal standard, the concentration of nimetazepam and its metabolite 7-aminonimetazepam could be determined by matrix matched calibration method. Extraction of the target compounds was performed by using methanol, followed by evaporation and being concentrated with nitrogen. The Limit of quantification concentrations of nimetazepam and its metabolite 7-aminonimetazepam in hair samples were both 25 pg/mg by established method. The concentrations of nimetazepam in hair samples obtained from 2 users were 27.4, and 22.0 pg/mg, respectively; the concentrations of 7-animonimetazepam in hair samples were 54.2 and 29.1 pg/mg, respectively. In our study, the 7-aminonimetazepam concentrations in hair was higher than those of nimetazepam in the authentic hair samples. To our knowledge, this is the first report to establish the detailed procedure for quantificating nimetazepam and 7-aminonimetazepam in human hair by LC-MS/MS.
    Matched MeSH terms: Limit of Detection
  10. Self-assembled silver nanoparticle-DNA on a dielectrode microdevice for determination of gynecologic tumors
    Li Z, Gopinath SCB, Lakshmipriya T, Anbu P, Perumal V, Wang X
    Biomed Microdevices, 2020 09 17;22(4):67.
    PMID: 32940771 DOI: 10.1007/s10544-020-00522-3
    Nanoscale materials have been employed in the past 2 decades in applications such as biosensing, therapeutics and medical diagnostics due to their beneficial optoelectronic properties. In recent years, silver nanoparticles (AgNPs) have gained attention due to their higher plasmon excitation efficiency than gold nanoparticles, as proved by sharper and stronger plasmon resonance peaks. The current work is focused on utilizing self-assembled DNA-AgNPs on microdevices for the detection of gynecological cancers. Human papilloma virus (HPV) mostly spreads through sexual transmittance and can cause various gynecological cancers, including cervical, ovarian and endometrial cancers. In particular, oncogene E7 from the HPV strain 16 (HPV-16 E7) is responsible for causing these cancers. In this research, the target sequence of HPV-16 E7 was detected by an AgNP-conjugated capture probe on a dielectrode sensor. The detection limit was in the range between 10 and 100 aM (by 3σ estimation). The sensitivity of the AgNP-conjugated probe was 10 aM and similar to the sensitivity of gold nanoparticle conjugation sensors, and the mismatched control DNA failed to detect the target, proving selective HPV detection. Morphological assessments on the AgNPs and the sensing surfaces by high-resolution microscopy revealed the surface arrangement. This sensing platform can be expanded to develop sensors for the detection various clinically relevant targets.
    Matched MeSH terms: Limit of Detection
  11. Fulltext A rapid and sensitive Loop-mediated isothermal amplification assay for detection of pork DNA based on porcine tRNA lys and ATPase 8 genes
    Abdullahi, U.F., Igwenagu, E., Aliyu, S., Mu’azu, A., Naim, R., Wan-Taib, W.R.
    International Food Research Journal, 2017;24(4):1357-1361.
    MyJurnal
    This study describes the development of a rapid and sensitive Loop-mediated isothermal
    amplification assay for detection of swine DNA in adulterated meat and meat products. The
    need to protect consumer’s right to eat foods of their choices, has made it imperative for
    researchers to develop efficient means of screening and certification of food products. Six sets
    of LAMP primers designed based on porcine tRNA lysine gene and ATPase subunit 8 genes
    were used for the assay. Amplification was carried out under constant temperature (630C), using
    a simple laboratory water bath. Average time spent in amplification and detection of results was
    25 min. All results were visually detected and confirmed by electrophoresis. Detection limit of
    the assay was 0.03 femtogram (fg) much high than the PCR assay, and detection probability of
    the assay was 100%. Detection of 0.5% of pork spiked with 99.5% of cattle beef is indicative
    of the sensitivity and robustness of the assay. This could serve as a prototype for development
    of a sensitive and inexpensive Swine DNA LAMP detection kit.
    Matched MeSH terms: Limit of Detection
  12. Fulltext Ascorbic acid quantification in Benincasa hispida fruit extracted using different solvents
    Fatariah, Z., Tengku Zulkhairuazha, T.Y., Wan Rosli, W.I.
    International Food Research Journal, 2015;22(1):208-212.
    MyJurnal
    Ascorbic acid or vitamin C is mostly found in natural products such as fruits and vegetables. High performance liquid chromatography (HPLC) method has been developed and validated to compare the ascorbic acid content in Benincasa hispida (Bh) fruit extract with three different extraction solvents; i) 3% metaphosphoric acid, ii) 3% citric acid and iii) distilled water. The compound has been detected and quantified by the use of HPLC coupled with UV-Vis detector. The amount of ascorbic acid detected in Bh fruit extract prepared with different extraction solvents; 3% metaphosphoric acid, 3% citric acid and distilled water were 13.18, 7.91 and 9.42 mg/100g respectively. Total run time was 6 min and the retention time was 2.60 min. Calibration curve was linear with the concentration range 1.00 – 16.00 μg/ml. Limits of detection was 0.24 μg/ml, limit of quantification was 0.81 μg/ml and recovery was 93.52%. The result showed ascorbic acid content is higher in Bh fruit extract with 3% metaphosphoric acid, followed by extract with distilled water and 3% citric acid. Thus, Bh is another novel fruit/ vegetable potentially used as food ingredient as it contains a good source of ascorbic acid that can be good for one’s health.
    Matched MeSH terms: Limit of Detection
  13. Quantitative HPLC analysis of gallic acid in benincasa hispida prepared with different extraction techniques
    Fatariah Z, Zulkhairuazha TT, Wan Rosli W
    Sains Malaysiana, 2014;43:1181-1187.
    Ash gourd (Benincasa hispida, Bh) is traditionally claimed useful in treating asthma, cough, diabetes, haemoptysis and hemorrhages from internal organs, epilepsy, fever and balancing of the body heat. One of the major phenolic acids presented in Benincasa hispida is gallic acid, a phenolic compound which is linked with its ability in reducing Type II diabetes. The aim of the present study was to investigate the effect of different extraction techniques on the concentration of gallic acid in Bh. The Bh extracts were prepared with three different techniques namely; fresh extract (FE), low heating (LH) and drying and heating (DH). The gallic acid has been detected and quantified using high performance liquid chromatography (HPLC) coupled with uv-Vis detector. The amount of gallic acid detected in FE, LH and DH were 0.036, 0.050 and 0 272 mg1100 g, respectively. The limits of detection was 0.75 liglmL while the limit of quantification and recovery were 2.50 liglmL and 95 .53% , respectively. In summary, HPLC technique coupled with vv detector systems able to quantify gallic acid in Bh extracts. The gallic acid were present at higher concentration in Bh extracted using drying and heating, followed by low heating and fresh extract methods.
    Matched MeSH terms: Limit of Detection
  14. Ionic liquid-impregnated agarose film two-phase micro-electrodriven membrane extraction (IL-AF-μ-EME) for the analysis of antidepressants in water samples
    Mohamad Hanapi NS, Sanagi MM, Ismail AK, Wan Ibrahim WA, Saim N, Wan Ibrahim WN
    J Chromatogr B Analyt Technol Biomed Life Sci, 2017 Mar 01;1046:73-80.
    PMID: 28142101 DOI: 10.1016/j.jchromb.2017.01.028
    The aim of this study was to investigate and apply supported ionic liquid membrane (SILM) in two-phase micro-electrodriven membrane extraction combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV) for pre-concentration and determination of three selected antidepressant drugs in water samples. A thin agarose film impregnated with 1-hexyl-3-methylimidazolium hexafluorophosphate, [C6MIM] [PF6], was prepared and used as supported ionic liquid membrane between aqueous sample solution and acceptor phase for extraction of imipramine, amitriptyline and chlorpromazine. Under the optimized extraction conditions, the method provided good linearity in the range of 1.0-1000μgL(-1), good coefficients of determination (r(2)=0.9974-0.9992) and low limits of detection (0.1-0.4μgL(-1)). The method showed high enrichment factors in the range of 110-150 and high relative recoveries in the range of 88.2-111.4% and 90.9-107.0%, for river water and tap water samples, respectively with RSDs of ≤7.6 (n=3). This method was successfully applied to the determination of the drugs in river and tap water samples. It is envisaged that the SILM improved the perm-selectivity by providing a pathway for targeted analytes which resulted in rapid extraction with high degree of selectivity and high enrichment factor.
    Matched MeSH terms: Limit of Detection
  15. Cardiovascular biomarker troponin I biosensor: Aptamer-gold-antibody hybrid on a metal oxide surface
    Hui H, Gopinath SCB, Ismail ZH, Chen Y, Pandian K, Velusamy P
    Biotechnol Appl Biochem, 2023 Apr;70(2):581-591.
    PMID: 35765758 DOI: 10.1002/bab.2380
    Myocardial infarction (MI) is highly related to cardiac arrest leading to death and organ damage. Radiological techniques and electrocardiography have been used as preliminary tests to diagnose MI; however, these techniques are not sensitive enough for early-stage detection. A blood biomarker-based diagnosis is an immediate solution, and due to the high correlation of troponin with MI, it has been considered to be a gold-standard biomarker. In the present research, the cardiac biomarker troponin I (cTnI) was detected on an interdigitated electrode sensor with various surface interfaces. To detect cTnI, a capture aptamer-conjugated gold nanoparticle probe and detection antibody probe were utilized and compared through an alternating sandwich pattern. The surface metal oxide morphology of the developed sensor was proven by microscopic assessments. The limit of detection with the aptamer-gold-cTnI-antibody sandwich pattern was 100 aM, while it was 1 fM with antibody-gold-cTnI-aptamer, representing 10-fold differences. Further, the high performance of the sensor was confirmed by selective cTnI determination in serum, exhibiting superior nonfouling. These methods of determination provide options for generating novel assays for diagnosing MI.
    Matched MeSH terms: Limit of Detection
  16. Investigations for the Possible Use of a Monoclonal Antibody Produced against Strongyloides ratti Antigen as an Immunodiagnostic Reagent for Active Strongyloidiasis
    Mahmuda A, Bande F, Abdulhaleem N, Abd Majid R, Awang Hamat R, Omar Abdullah W, et al.
    Iran J Parasitol, 2018 8 3;13(2):204-214.
    PMID: 30069204
    Background: Currently, most of the available serological diagnostic kits for strongyloidiasis are based on the use of the crude antigens of Strongyloides ratti, which are good, but with less sensitivity towards the infection. Hence, this study aimed to produce and evaluate monoclonal antibody for detecting soluble parasite antigen in animal sera.

    Methods: The study was conducted in the Department of Medical Microbiology and Parasitology, University Putra Malaysia in 2014-2017. Saline extract protein from the infective larvae of S. ratti was used to immunize BALB/c mice and subsequent fusion of the B-cells with myeloma cells (SP2/0) using 50% PEG. The hybridomas were cultured in HAT medium and cloned by limiting dilutions. Positive hybrids were screened by indirect ELISA. The ascites fluid from the antibody-secreting hybridoma was purified and the MAb was characterized by western-blots and evaluated in sandwich ELISA for reactivity against the homologous and heterologous antigens.

    Results: An IgG1 that recognizes a 30 and 34 kDa protein bands was obtained. The MAb was recognized by all S. ratti-related antigens and cross-reacted with only Toxocara canis antigens in both assays. The minimum antigen detection limit was found to be 5 ng/ml. All antibody-positive rat and dog sera evaluated have shown antigen-positive reactions in Sandwich-ELISA.

    Conclusion: The MAb produced, was able to detect antigens in strongyloidiasis and toxocariasis in animal models and may also be useful for the serological detection of active strongyloidiasis and visceral toxocariasis in human sera.

    Matched MeSH terms: Limit of Detection
  17. A cell-based potentiometric biosensor using the fungus Lentinus sajor-caju for permethrin determination in treated wood
    Arip MN, Heng LY, Ahmad M, Ujang S
    Talanta, 2013 Nov 15;116:776-81.
    PMID: 24148473 DOI: 10.1016/j.talanta.2013.07.065
    The characteristics of a potentiometric biosensor for the determination of permethrin in treated wood based on immobilised cells of the fungus Lentinus sajor-caju on a potentiometric transducer are reported this paper. The potentiometric biosensor was prepared by immobilisation of the fungus in alginate gel deposited on a pH-sensitive transducer employing a photocurable acrylic matrix. The biosensor gave a good response in detecting permethrin over the range of 1.0-100.0 µM. The slope of the calibration curve was 56.10 mV/decade with detection limit of 1.00 µM. The relative standard deviation for the sensor reproducibility was 4.86%. The response time of the sensor was 5 min at optimum pH 8.0 with 1.00 mg/electrode of fungus L. sajor-caju. The permethrin biosensor performance was compared with the conventional method for permethrin analysis using high performance liquid chromatography (HPLC), and the analytical results agreed well with the HPLC method (at 95% confidence limit). There was no interference from commonly used organophosphorus pesticides such as diazinon, parathion, paraoxon, and methyl parathion.
    Matched MeSH terms: Limit of Detection
  18. Dual panel multiplex PCR assay for rapid detection of medically important fungi and resistant species of candida and aspergillus
    Jacinta Santhanam, Mohd Hanif Jainlabdin, Ang LC, Tzar Mohd Nizam
    Sains Malaysiana, 2018;47:489-498.
    Invasive fungal infections (IFIs) have risen dramatically in recent years among high risk immunocompromised patients.
    Rapid detection of fungal pathogens is crucial to timely and accurate antifungal therapy. Two multiplex polymerase
    chain reaction (PCR) assays were developed to detect major fungal species that cause invasive infections and identify
    resistant species. Genus specific primers for Candida, Aspergillus, Fusarium and species specific primers for Candida
    glabrata, Candida krusei and Aspergillus terreus which are known to be clinically resistant species, were designed from
    the internal transcribed spacer (ITS) regions of ribosomal ribonucleic acid (rRNA) gene complex. Both assays were
    performed simultaneously to promote rapid detection of fungal isolates based on distinct amplicon sizes. Inclusion of the
    universal fungal primers ITS 1 and ITS 4 in the genus specific assay produced a second amplicon for each isolate which
    served to confirm the detection of a fungal target. The limit of detection for the genus specific assay was 1 nanogram
    (ng) deoxyribonucleic acid (DNA) for Aspergillus fumigatus and Candida albicans, 0.1 ng DNA for Fusarium solani, while
    the species-specific assay detected 0.1 ng DNA of A. terreus and 10 picogram (pg) DNA of C. krusei and C. glabrata. The
    multiplex PCR assays, apart from universal detection of any fungal target, are able to detect clinically important fungi
    and differentiate resistant species rapidly and accurately, which can contribute to timely implementation of effective
    antifungal regime.
    Matched MeSH terms: Limit of Detection
  19. Fulltext Single-tube, dual channel pentaplexing for the identification of Candida strains associated with human infection
    Jainlabdin MH, Batra A, Sánchez Paredes E, Hernández Hernández F, Fu G, Tovar-Torres J
    Sci Rep, 2019 10 11;9(1):14692.
    PMID: 31604994 DOI: 10.1038/s41598-019-51198-6
    Invasive candidiasis is one of the most common nosocomial fungal infections worldwide. Delayed implementation of effective antifungal treatment caused by inefficient Candida diagnosis contributes to its notoriously high mortality rates. The availability of better Candida diagnostic tools would positively impact patient outcomes. Here, we report on the development of a single-tube, dual channel pentaplex molecular diagnostic assay based on Multiplex Probe Amplification (MPA) technology. It allows simultaneous identification of C. auris, C. glabrata and C. krusei, at species-level as well as of six additional albicans and non-albicans pathogenic Candida at genus level. The assay overcomes the one-channel one-biomarker limitation of qPCR-based assays. Assay specificities are conferred by unique biomarker probe pairs with characteristic melting temperatures; post-amplification melting curve analysis allows simple identification of the infectious agent. Alerting for the presence of C. auris, the well-characterised multi-drug resistant outbreak strain, will facilitate informed therapy decisions and aid antifungal stewardship. The MPA-Candida assay can also be coupled to a pan-Fungal assay when differentiation between fungal and bacterial infections might be desirable. Its multiplexing capacity, detection range, specificity and sensitivity suggest the potential use of this novel MPA-Candida assay in clinical diagnosis and in the control and management of hospital outbreaks.
    Matched MeSH terms: Limit of Detection
  20. Fulltext Subtractive inhibition assay for the detection of Campylobacter jejuni in chicken samples using surface plasmon resonance
    Masdor NA, Altintas Z, Shukor MY, Tothill IE
    Sci Rep, 2019 09 20;9(1):13642.
    PMID: 31541137 DOI: 10.1038/s41598-019-49672-2
    In this work, a subtractive inhibition assay (SIA) based on surface plasmon resonance (SPR) for the rapid detection of Campylobacter jejuni was developed. For this, rabbit polyclonal antibody with specificity to C. jejuni was first mixed with C. jejuni cells and unbound antibody was subsequently separated using a sequential process of centrifugation and then detected using an immobilized goat anti-rabbit IgG polyclonal antibody on the SPR sensor chip. This SIA-SPR method showed excellent sensitivity for C. jejuni with a limit of detection (LOD) of 131 ± 4 CFU mL-1 and a 95% confidence interval from 122 to 140 CFU mL-1. The method has also high specificity. The developed method showed low cross-reactivity to bacterial pathogens such as Salmonella enterica serovar Typhimurium (7.8%), Listeria monocytogenes (3.88%) and Escherichia coli (1.56%). The SIA-SPR method together with the culturing (plating) method was able to detect C. jejuni in the real chicken sample at less than 500 CFU mL-1, the minimum infectious dose for C. jejuni while a commercial ELISA kit was unable to detect the bacterium. Since the currently available detection tools rely on culturing methods, which take more than 48 hours to detect the bacterium, the developed method in this work has the potential to be a rapid and sensitive detection method for C. jejuni.
    Matched MeSH terms: Limit of Detection
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