Displaying publications 1 - 20 of 54 in total

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  1. Abdul Karim N', Wan Ibrahim WA, Sanagi MM, Abdul Keyon AS
    Electrophoresis, 2016 10;37(20):2649-2656.
    PMID: 27434368 DOI: 10.1002/elps.201600207
    Online preconcentration using electrokinetic supercharging (EKS) was proposed to enhance the sensitivity of separation for endocrine disrupting chemical (methylparaben (MP)) and phenolic pollutants (2-nitrophenol (NP) and 4-chlorophenol (CP)) in water sample. Important EKS and separation conditions such as the concentration of BGE; the choice of terminating electrolyte (TE); and the injection time of leading electrolyte (LE), sample, and TE were optimized. The optimum EKS-CE conditions were as follows: BGE comprising of 12 mM sodium tetraborate pH 10.1, 100 mM sodium chloride as LE hydrodynamically injected at 50 mbar for 30 s, electrokinetic injection (EKI) of sample at -3 kV for 200 s, and 100 mM CHES as TE hydrodynamically injected at 50 mbar for 40 s. The separation was conducted at negative polarity mode and UV detection at 214 nm. Under these conditions, the sensitivity of analytes was enhanced from 100- to 737-fold as compared to normal CZE with hydrodynamic injection, giving LOD of 4.89, 5.29, and 53 μg/L for MP, NP and CP, respectively. The LODs were adequate for the analysis of NP and CP in environmental water sample having concentration at or lower than their maximum admissible concentration limit (240 and 2000 μg/L for NP and CP). The LOD of MP can be suitable for the analysis of MP exists at mid-microgram per liter level, even though the LOD was slightly higher than the concentration usually found in water samples (from ng/L to 1 μg/L). The method repeatabilities (%RSD) were in the range of 1.07-2.39% (migration time) and 8.28-14.0% (peak area).
    Matched MeSH terms: Electrophoresis, Capillary/methods*
  2. Wan-Ibrahim WI, Ashrafzadeh A, Singh VA, Hashim OH, Abdul-Rahman PS
    Electrophoresis, 2016 09;37(17-18):2328-37.
    PMID: 27062367 DOI: 10.1002/elps.201500522
    Sarcoma is a malignant tumor that originates from the bone or soft tissue. In this study, abundances of serum amyloid A (SAA) in patients with pleomorphic sarcoma (PS), chondrosarcoma (CS), and osteosarcoma (OS) were analyzed and compared with those from their respective age-matched healthy control subjects. Results obtained from our analysis by 2DE showed that the levels of SAA were markedly elevated in patients with PS and OS, which are highly metastatic, while in patients with CS, which is a less aggressive sarcoma, the increase appeared less pronounced. A similar trend of altered abundances was also observed when the levels of SAA in the subjects were estimated using Western blot, ELISA, and multiple-reaction monitoring analyses. Absolute quantification using multiple-reaction monitoring further demonstrated that the increased abundance of SAA in patients with PS, OS, and CS was mainly attributed to isoform SAA1. In view of the different degrees of tumor malignancy in PS, OS, and CS, our data suggest their apparent correlation with the levels of SAA in the patients.
    Matched MeSH terms: Electrophoresis, Gel, Two-Dimensional
  3. Kwan SH, Wan-Ibrahim WI, Juvarajah T, Fung SY, Abdul-Rahman PS
    Electrophoresis, 2021 02;42(3):233-244.
    PMID: 33085102 DOI: 10.1002/elps.202000142
    Milk serves as the sole nutrition for newborns, as well as a medium for the transfer of immunological components from the mother to the baby. This study reveals different glycoprotein profiles obtained from human, bovine, and caprine milk and their potential roles in supporting infant growth. Proteins from these three milk samples are separated and analyzed using two-dimensional gel electrophoresis (2-DE). Glycosylated proteins from all samples are enriched by affinity chromatography using lectins from the seeds of Artocarpus integer before analysis using LC/MS-QTOF. The glycoproteome profiling demonstrates that glycosylated proteins are higher in caprine milk compared to other samples. Analysis using LC/MS-QTOF identified 42 O-glycosylated and 56 N-glycosylated proteins, respectively. Among those identified, human milk has 17 glycoproteins, which are both O- and N-glycosylated, whereas caprine and bovine have 10 and 1, respectively. Only glycoproteins from human milk have shown positive matching to important human biological pathways, such as vesicle-mediated transport, immune system and hemostasis pathways. Human milk remains unique for human babies with the presence of antibodies in the form of immunoglobulins that are lacking in ruminant milk proteomes.
  4. Tan XT, Amran FB, Thayan R, Ahmad N, Jaafar R, Haron R, et al.
    Electrophoresis, 2017 09;38(17):2141-2149.
    PMID: 28524240 DOI: 10.1002/elps.201600471
    Leptospirosis is an emerging zoonotic infectious disease in Malaysia. The symptoms of leptospirosis vary from mild nonspecific flu-like illness to a severe condition which is usually associated with serious complication and fatality. To study the protein expression profile of mild and severe leptospirosis, 15 paired sera were collected from the patients who were mildly infected and following that progressed to severe stage. The proteome profiles of mild and severe cases were studied using 2DE analysis in combination with LC-MS/MS. The expression of proteins that were significantly different and had a fold difference of at least 2 had been identified and then validated using Western blot. Our study demonstrated apolipoprotein A-I (APOA-I), serum amyloid A (SAA), transferrin (TF), haptoglobin (HP) and transthyretin (TTR) have significantly different expression between mild and severe leptospirosis. The Ingenuity Pathway Analysis software suggested the expression of these five proteins were modulated by acute phase response signaling pathway. Besides that, a functional network of lipid metabolism, molecular transport and small molecule biochemistry that interconnects these five proteins with interactomes also had been predicted by this software. In conclusion, this finding supports the potential of these five proteins to be the biomarkers for mild and severe human leptospirosis.
    Matched MeSH terms: Electrophoresis, Gel, Two-Dimensional
  5. Al Azzam KM, Saad B, Aboul-Enein HY
    Electrophoresis, 2010 Sep;31(17):2957-63.
    PMID: 20690150 DOI: 10.1002/elps.201000266
    Binding constants for the enantiomers of modafinil with the negatively charged chiral selector sulfated-β-CD (S-β-CD) using CE technique is presented. The calculations of the binding constants employing three different linearization plots (double reciprocal, X-reciprocal and Y-reciprocal) were performed from the electrophoretic mobility values of modafinil enantiomers at different concentrations of S-β-CD in the BGE. The highest inclusion affinity of the modafinil enantiomers were observed for the S-enantiomer-S-β-CD complex, in agreement with the computational calculations performed previously. Binding constants for each enantiomer-S-β-CD complex at different temperatures, as well as thermodynamic parameters for binding, were calculated. Host-guest binding constants using the double reciprocal fit showed better linearity (r(2)>0.99) at all temperatures studied (15-30°C) and compared with the other two fit methods. The linear van't Hoff (15-30°C) plot obtained indicated that the thermodynamic parameters of complexation were temperature dependent for the enantiomers.
    Matched MeSH terms: Electrophoresis, Capillary/methods*
  6. Al-Obaidi JR
    Electrophoresis, 2016 05;37(10):1257-63.
    PMID: 26891916 DOI: 10.1002/elps.201600031
    Mushrooms are considered an important food for their traditionally famous nutritional and medicinal values, although much information about their potential at the molecular level is unfortunately unknown. Edible mushrooms include fungi that are either collected wild or cultivated. Many important species are difficult to cultivate but attempts have been made with varying degrees of success, with the results showing unsatisfactory economical cultivation methods. Recently, proteomic analysis has been developed as a powerful tool to study the protein content of fungi, particularly basidiomycetes. This mini-review article highlights the contribution of proteomics platforms to the study of edible mushrooms, focusing on the molecular mechanisms involved in developmental stages. This includes extracellular and cytoplasmic effector proteins that have potential or are involved in the synthesis of anticancer, antidiabetic, antioxidant, and antibiotic, in blood pressure control, in the supply of vitamins and minerals, and in other responses to environmental changes. The contribution of different proteomics techniques including classical and more advanced techniques is also highlighted.
  7. Jamil NAM, Rahmad N, Rosli NHM, Al-Obaidi JR
    Electrophoresis, 2018 12;39(23):2954-2964.
    PMID: 30074628 DOI: 10.1002/elps.201800185
    Wax apple is one of the underutilized fruits that is considered a good source of fibers, vitamins, minerals as well as antioxidants. In this study, a comparative analysis of the developments of wax fruit ripening at the proteomic and metabolomic level was reported. 2D electrophoresis coupled with MALDI-TOF/TOF was used to compare the proteome profile from three developmental stages named immature, young, and mature fruits. In general, the protein expression profile and the identified proteins function were discussed for their potential roles in fruit physiological development and ripening processes. The metabolomic investigation was also performed on the same samples using quadrupole LC-MS (LC-QTOF/MS). Roles of some of the differentially expressed proteins and metabolites are discussed in relation to wax apple ripening during the development. This is the first study investigating the changes in the proteins and metabolites in wax apple at different developmental stages. The information obtained from this research will be helpful in developing biomarkers for breeders and help the plant researchers to avoid wax apple cultivation problems such as fruit cracking.
  8. Goodwin W, Alimat S
    Electrophoresis, 2017 04;38(7):1007-1015.
    PMID: 28008628 DOI: 10.1002/elps.201600383
    The SNPforID consortium identified a panel of 52 SNPs for forensic analysis that has been used by several laboratories worldwide. The original analysis of the 52 SNPs was based on a single multiplex reaction followed by two single-base-extension (SBE) reactions each of which was analyzed using capillary electrophoresis. The SBE assays were designed for high throughput genetic analyzers and were difficult to use on the single capillary ABI PRISM 310 Genetic Analyzer and the latest generation 3500 Genetic Analyzer, as sensitivity on the 310 was low and separation of products on the 3500 with POP-7™ was poor. We have modified the original assay and split it into four multiplex reactions, each followed by an SBE assay. These multiplex assays were analyzed using polymer POP-4™ on ABI 310 PRISM® and polymers POP-4™, POP-6™ and POP-7™ on the 3500 Genetic Analyzer. The assays were sensitive and reproducible with input DNA as low as 60 pg using both the ABI 310 and 3500. In addition, we found that POP-6™ was most effective with the 3500, based on the parameters that we assessed, achieving better separation of the small SBE products; this conflicted with the recommended use of POP-7™ by the instrument manufacturer. To support the use of the SNP panel in casework in Malaysia we have created an allele frequency database from 325 individuals, representing the major population groups within Malaysia. Population and forensic parameters were estimated for all populations and its efficacy evaluated using 51 forensic samples from challenging casework.
    Matched MeSH terms: Electrophoresis, Capillary/methods
  9. Bon MC
    Electrophoresis, 1996 Jul;17(7):1248-52.
    PMID: 8855412
    A combination of a modified Feret' (Silvae Genet. 1971, 20, 46-50) extraction buffer and two types of electrophoresis with acrylamide and starch gels were used to characterize allozymes in mature vegetative tissue of a commercially high value species of rattans (Calamus subinermis). From the analysis of allelic segregation from single maternal rattans and their offspring, genetic control of the 16 observed banding zones, which were consistently scorable, was assumed. Seventeen gene loci were identified. The percentage of polymorphic loci within Calamus subinermis was much higher (70.5%) than expected levels of genetic diversity for tropical woody and non-woody species. It is thought that the protocol described may be applied to the analysis of the genetic diversity of all the endangered Calamus species.
    Matched MeSH terms: Electrophoresis/methods*; Electrophoresis, Starch Gel/methods
  10. Keyon AS, Guijt RM, Gaspar A, Kazarian AA, Nesterenko PN, Bolch CJ, et al.
    Electrophoresis, 2014 May;35(10):1496-503.
    PMID: 24591173 DOI: 10.1002/elps.201300353
    Paralytic shellfish toxins (PSTs) are produced by marine and freshwater microalgae and accumulate in shellfish including mussels, oysters, and scallops, causing possible fatalities when inadvertently consumed. Monitoring of PST content of shellfish is therefore important for food safety, with currently approved methods based on HPLC, using pre- or postcolumn oxidation for fluorescence detection (HPLC-FLD). CE is an attractive alternative for screening and detection of PSTs as it is compatible with miniaturization and could be implemented in portable instrumentation for on-site monitoring. In this study, CE methods were developed for C(4) D, FLD, UV absorption detection, and MS-making this first report of C(4) D and FLD for PSTs detection. Because most oxidized toxins are neutral, MEKC was used in combination with FLD. The developed CZE-UV and CZE-C(4) D methods provide better resolution, selectivity, and separation efficiency compared to CZE-MS and MEKC-FLD. The sensitivity of the CZE-C(4) D and MEKC-FLD methods was superior to UV and MS, with LOD values ranging from 140 to 715 ng/mL for CZE-C(4) D and 60.9 to 104 ng/mL for MEKC-FLD. With the regulatory limit for shellfish samples of 800 ng/mL, the CZE-C(4) D and MEKC-FLD methods were evaluated for the screening and detection of PSTs in shellfish samples. While the CZE-C(4) D method suffered from significant interferences from the shellfish matrix, MEKC-FLD was successfully used for PST screening of a periodate-oxidized mussel sample, with results confirmed by HPLC-FLD. This confirms the potential of MEKC-FLD for screening of PSTs in shellfish samples.
    Matched MeSH terms: Electrophoresis, Capillary/methods*
  11. Deivasigamani R, Abdul Nasir NS, Mohamed MA, Buyong MR
    Electrophoresis, 2022 Feb;43(4):609-620.
    PMID: 34859896 DOI: 10.1002/elps.202100207
    This article describes a dielectrophoresis (DEP)-based simulation and experimental study of human epidermal keratinocyte (HEK) cells for wounded skin cell migration toward rapid epithelialization. MyDEP is a standalone software designed specifically to study dielectric particles and cell response to an alternating current (AC) electric field. This method demonstrated that negative dielectrophoresis (NDEP ) occurs in HEK cells at a wide frequency range in highly conductive medium. The finite element method was used to characterize particle trajectory based on DEP and drag force. The performance of the system was assessed using HEK cells in a highly conductive EpiLife suspending medium. The DEP experiment was performed by applying sinusoidal wave AC potential at the peak-to-peak voltage of 10 V in a tapered aluminum microelectrode array from 100 kHz to 1 MHz. We experimentally observed the occurrence of NDEP, which attracted HEK cells toward the local electric field minima in the region of interest. The DIPP-MotionV software was used to track cell migration in the prerecorded video via an automatic marker and estimate the average speed and acceleration of the cells. The results showed that HEK cell migration was accomplished approximately at 6.43 μm/s at 100 kHz with 10 V, and FDEP caused the cells to migrate and align at the target position, which resulted in faster wound closures because of the application of an electric field frequency to HEK cells in random locations.
  12. Deivasigamani R, Mohd Maidin NN, Abdul Nasir NS, Abdulhameed A, Ahmad Kayani AB, Mohamed MA, et al.
    Electrophoresis, 2023 Mar;44(5-6):573-620.
    PMID: 36604943 DOI: 10.1002/elps.202200203
    Dielectrophoresis (DEP) bioparticle research has progressed from micro to nano levels. It has proven to be a promising and powerful cell manipulation method with an accurate, quick, inexpensive, and label-free technique for therapeutic purposes. DEP, an electrokinetic phenomenon, induces particle movement as a result of polarization effects in a nonuniform electrical field. This review focuses on current research in the biomedical field that demonstrates a practical approach to DEP in terms of cell separation, trapping, discrimination, and enrichment under the influence of the conductive medium in correlation with bioparticle viability. The current review aims to provide readers with an in-depth knowledge of the fundamental theory and principles of the DEP technique, which is influenced by conductive medium and to identify and demonstrate the biomedical application areas. The high conductivity of physiological fluids presents obstacles and opportunities, followed by bioparticle viability in an electric field elaborated in detail. Finally, the drawbacks of DEP-based systems and the outlook for the future are addressed. This article will aid in advancing technology by bridging the gap between bioscience and engineering. We hope the insights presented in this review will improve cell suspension medium and promote DEP-viable bioparticle manipulation for health-care diagnostics and therapeutics.
  13. Rozaini AZA, Abdulhameed A, Deivasigamani R, Nadzreen N, Zin NM, Kayani AA, et al.
    Electrophoresis, 2023 Aug;44(15-16):1220-1233.
    PMID: 37259263 DOI: 10.1002/elps.202200276
    Characterization of antibiotic-resistant bacteria is a significant concern that persists for the rapid classification and analysis of the bacteria. A technology that utilizes the manipulation of antibiotic-resistant bacteria is key to solving the significant threat of these pathogenic bacteria by rapid characterization profile. Dielectrophoresis (DEP) can differentiate between antibiotic-resistant and susceptible bacteria based on their physical structure and polarization properties. In this work, the DEP response of two Gram-positive bacteria, namely, Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-susceptible S. aureus (MSSA), was investigated and simulated. The DEP characterization was experimentally observed on the bacteria influenced by oxacillin and vancomycin antibiotics. MSSA control without antibiotics has crossover frequencies ( f x 0 ${f_{x0}}$ ) from 6 to 8 MHz, whereas MRSA control is from 2 to 3 MHz. The f x 0 ${f_{x0}}$ changed when bacteria were exposed to the antibiotic. As for MSSA, the f x 0 ${f_{x0}}$ decreased to 3.35 MHz compared to f x 0 ${f_{x0}}$ MSSA control without antibiotics, MRSA, f x 0 ${f_{x0}}$ increased to 7 MHz when compared to MRSA control. The changes in the DEP response of MSSA and MRSA with and without antibiotics were theoretically proven using MyDEP and COMSOL simulation and experimentally based on the modification to the bacteria cell walls. Thus, the DEP response can be employed as a label-free detectable method to sense and differentiate between resistant and susceptible strains with different antibiotic profiles. The developed method can be implemented on a single platform to analyze and identify bacteria for rapid, scalable, and accurate characterization.
  14. Tan HS, Jacoby RP, Ong-Abdullah M, Taylor NL, Liddell S, Chee WW, et al.
    Electrophoresis, 2017 04;38(8):1147-1153.
    PMID: 28198080 DOI: 10.1002/elps.201600506
    Oil palm is one of the most productive oil bearing crops grown in Southeast Asia. Due to the dwindling availability of agricultural land and increasing demand for high yielding oil palm seedlings, clonal propagation is vital to the oil palm industry. Most commonly, leaf explants are used for in vitro micropropagation of oil palm and to optimize this process it is important to unravel the physiological and molecular mechanisms underlying somatic embryo production from leaves. In this study, a proteomic approach was used to determine protein abundance of mature oil palm leaves. To do this, leaf proteins were extracted using TCA/acetone precipitation protocol and separated by 2DE. A total of 191 protein spots were observed on the 2D gels and 67 of the most abundant protein spots that were consistently observed were selected for further analysis with 35 successfully identified using MALDI TOF/TOF MS. The majority of proteins were classified as being involved in photosynthesis, metabolism, cellular biogenesis, stress response, and transport. This study provides the first proteomic assessment of oil palm leaves in this important oil crop and demonstrates the successful identification of selected proteins spots using the Malaysian Palm Oil Board (MPOB) Elaeis guineensis EST and NCBI-protein databases. The MS data have been deposited in the ProteomeXchange Consortium database with the data set identifier PXD001307.
    Matched MeSH terms: Electrophoresis, Gel, Two-Dimensional
  15. Liew YK, Neela V, Hamat RA, Nordin SA, Chong PP
    Electrophoresis, 2013 Feb;34(3):397-400.
    PMID: 23161123 DOI: 10.1002/elps.201200380
    The typical concentration of protein loaded varies from 0.13 to 1.40 μg/μL for a classical silver staining method in 2DE gel. Here, we present a simple modified classical silver staining method by modifying the silver impregnation and development reaction steps. This modified method detects the protein spots at extremely low loaded concentrations, ranging from 0.0048 to 0.0480 μg/μL. We recommend this modified silver staining as an excellent method for the limited biological samples used for silver-stained 2DE analysis. Altogether, the protocol takes close to two days from first dimension separation to second dimension separation, followed by silver staining, scanning, and analysis.
    Matched MeSH terms: Electrophoresis, Gel, Two-Dimensional/methods*
  16. Anada RP, Wong KT, Jayapalan JJ, Hashim OH, Ganesan D
    Electrophoresis, 2018 09;39(18):2308-2315.
    PMID: 29570807 DOI: 10.1002/elps.201700407
    The Glasgow Coma Scale (GCS), which classifies patients into mild, moderate or severe traumatic brain injury (TBI), is a system used to prioritize treatment and prognosticate the severity of head injury. In this study, sera of patients with various stages of TBI, as well as control subjects, were analyzed to screen for proteins that may be used to complement the GCS system. By subjecting pooled serum samples to iTRAQ analysis for quantitative comparison of protein abundance, and attesting their altered levels using ELISA, we have detected increased levels of serum amyloid A, C-reactive protein, leucine-rich alpha-2-glycoprotein, lipopolysaccharide-binding protein, fibronectin, vitronectin and alpha-1-antichymotrypsin in patients across all strata of TBI relative to the controls. However, kininogen was decreased only in moderate and severe TBI, whereas apolipoprotein E and zinc-alpha-2-glycoprotein were only increased in severe TBI. Hence, we propose a panel of serum biomarkers, which if analyzed within 24 h of the injury, can be used to diagnose patients with TBI into mild, moderate or severe stratification objectively, thus complementing the traditional GCS.
  17. Nolan MJ, Jex AR, Upcroft JA, Upcroft P, Gasser RB
    Electrophoresis, 2011 Aug;32(16):2075-90.
    PMID: 23479788
    We barcoded 25 in vitro isolates (representing 92 samples) of Giardia duodenalis from humans and other animals, which have been assembled by the Upcroft team at the Queensland Institute of Medical Research over a period of almost three decades. We used mutation scanning-coupled sequencing of loci in the triosephosphate isomerase, glutamate dehydrogenase and β-giardin genes, combined with phylogenetic analysis, to genetically characterise them. Specifically, the isolates (n514) of G. duodenalis from humans from Australia (AD113; BRIS/83/HEPU/106; BRIS/87/HEPU/713; BRIS/89/HEPU/1003; BRIS/92/HEPU/1541; BRIS/92/HEPU/1590; BRIS/92/HEPU/2443; BRIS/93/HEPU/1706), Malaysia (KL/92/IMR/1106) and Afghanistan (WB), a cat from Australia (BAC2), a sheep from Canada (OAS1) and a sulphur-crested cockatoo from Australia (BRIS/95/HEPU/2041) represented assemblage A (sub-assemblage AI-1, AI-2 or AII-2); isolates (n510) from humans from Australia (BRIS/91/HEPU/1279; BRIS/92/HEPU/2342; BRIS/92/HEPU/2348; BRIS/93/HEPU/1638; BRIS/93/HEPU/1653; BRIS/93/HEPU/1705; BRIS/93/HEPU/1718; BRIS/93/HEPU/1727), Papua New Guinea (BRIS/92/HEPU/1487) and Canada (H7) represented assemblage B (sub-assemblage BIV) and an isolate from cattle from Australia (BRIS/92/HEPU/1709) had a match to assemblage E. Isolate BRIS/90/HEPU/1229 from a human from Australia was shown to represent a mixed population of assemblages A and B. These barcoded isolates (including stocks and derived lines) now allow direct comparisons of experimental data among laboratories and represent a massive resource for transcriptomic, proteomic, metabolic and functional genomic studies using advanced molecular technologies.
  18. Yunus NA, Nili H, Green NG
    Electrophoresis, 2013 Apr;34(7):969-78.
    PMID: 23436439 DOI: 10.1002/elps.201200466
    Dielectrophoresis is the movement of particles in nonuniform electric fields and has been of interest for application to manipulation and separation at and below the microscale. This technique has the advantages of being noninvasive, nondestructive, and noncontact, with the movement of particle achieved by means of electric fields generated by miniaturized electrodes and microfluidic systems. Although the majority of applications have been above the microscale, there is increasing interest in application to colloidal particles around a micron and smaller. This paper begins with a review of colloidal and nanoscale dielectrophoresis with specific attention paid to separation applications. An innovative design of integrated microelectrode array and its application to flow-through, continuous separation of colloidal particles is then presented. The details of the angled chevron microelectrode array and the test microfluidic system are then discussed. The variation in device operation with applied signal voltage is presented and discussed in terms of separation efficiency, demonstrating 99.9% separation of a mixture of colloidal latex spheres.
    Matched MeSH terms: Electrophoresis/instrumentation*; Electrophoresis/methods*
  19. Abdulhameed A, Mohtar MN, Hamidon MN, Halin IA
    Electrophoresis, 2022 Feb;43(3):487-494.
    PMID: 34679198 DOI: 10.1002/elps.202100268
    The assembly of carbon nanotubes (CNTs) across planner electrodes using dielectrophoresis (DEP) is one of the standard methods used to fabricate CNT-based devices such as sensors. The medium drag velocity caused by electrokinetic phenomena such as electrothermal and electroosmotic might drive CNTs away from the deposition area. This problem becomes critical at large-scale electrode structures due to the high attenuation of the DEP force. Herein, we simulated and experimentally validated a novel DEP setup that uses a top glass cover to minimize the medium drag velocity. The simulation results showed that the drag velocity can be reduced by 2-3 orders of magnitude compared with the basic DEP setup. The simulation also showed that the optimum channel height to result in a significant drag velocity reduction was between 100 μm and 240 μm. We experimentally report, for the first time, the assembly and alignment of CNT bridges across indium tin oxide (ITO) electrodes with spacing up to 125 μm. We also derived an equation to optimize the CNT's concentration in suspensions based on the electrode gap width and channel height. The deposition of long CNTs across ITO electrodes has potential use in transparent electronics and microfluidic systems.
  20. Jessie K, Jayapalan JJ, Rahim ZH, Hashim OH
    Electrophoresis, 2014 Dec;35(24):3504-11.
    PMID: 25223738 DOI: 10.1002/elps.201400252
    Prolonged chewing of betel quid is known to cause oral diseases, including cancer. The present study was performed to screen for aberrant proteins in the saliva of habitual betel quid chewers compared to nonchewers. Saliva of female subjects (n = 10) who had been chewing betel quid for more than 20 years and nonbetel quid chewers (n = 10) of the same gender and range of age was analyzed by gel-based proteomics. Increased structural microheterogeneity of saliva haptoglobin beta chains indicated by shifts of focused spots similar to that earlier reported in patients with oral squamous cell carcinoma, and their relatively higher abundance compared to nonbetel quid chewers, were detected in saliva protein profiles of all chewers. In addition, the majority of the betel quid chewers also showed significant higher abundance of hemopexin, alpha-1B glycoprotein, alpha1-antitrypsin, complement C3, and transthyretin. These proteins had previously been associated with several different cancers. Our data demonstrated different forms of protein aberration in the saliva of betel quid chewers, which may be indicative of early oral precancerous conditions.
    Matched MeSH terms: Electrophoresis, Gel, Two-Dimensional
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