Browse publications by year: 2020

  1. Naderipour A, Abdul-Malek Z, Ramachandaramurthy VK, Miveh MR, Moghaddam MJH, Guerrero JM
    Sci Rep, 2020 09 18;10(1):15335.
    PMID: 32948807 DOI: 10.1038/s41598-020-72152-x
    An amendment to this paper has been published and can be accessed via a link at the top of the paper.
    MeSH terms: Humans
  2. Mani MS, Joshi MB, Shetty RR, DSouza VL, Swathi M, Kabekkodu SP, et al.
    Toxicol Lett, 2020 Dec 15;335:11-27.
    PMID: 32949623 DOI: 10.1016/j.toxlet.2020.09.010
    Lead is a toxin of great public health concern affecting the young and aging population. Several factors such as age, gender, lifestyle, dose, and genetic makeup result in interindividual variations to lead toxicity mainly due to variations in metabolic consequences. Hence, the present study aimed to examine dose-dependent lead-induced systemic changes in metabolism using rat model by administering specific doses of lead such as 10 (low lead; L-Pb), 50 (moderate lead; M-Pb), and 100 mg/kg (high lead; H-Pb) body weight for a period of one month. Biochemical and haematological analysis revealed that H-Pb was associated with low body weight and feed efficiency, low total protein levels (p ≤ 0.05), high blood lead (Pb-B) levels (p ≤ 0.001), low ALAD (δ-aminolevulinate dehydratase) activity (p ≤ 0.0001), high creatinine (p ≤ 0.0001) and blood urea nitrogen (BUN) (p ≤ 0.01) levels, elevated RBC and WBC counts, reduced haemoglobin and blood cell indices compared to control. Spatial learning and memory test revealed that H-Pb exposed animals presented high latency to the target quadrant and escape platform compared to other groups indicating H-Pb alters cognition function in rats. Histopathological changes were observed in liver and kidney as they are the main target organs of lead toxicity. LC-MS analysis further revealed that Butyryl-L-carnitine (p ≤ 0.01) and Ganglioside GD2 (d18:0/20:0) (p ≤ 0.05) levels were significantly reduced in H-Pb group compared to all groups. Further, pathway enrichment analysis revealed abundance and significantly modulated metabolites associated with oxidative stress pathways. The present study is the first in vivo model of dose-dependent lead exposure for serum metabolite profiling.
    MeSH terms: Porphobilinogen Synthase; Animals; Blood Urea Nitrogen; Body Weight; Chromatography, Liquid; Cognition; Creatinine; Gangliosides; Hemoglobins; Lead; Lead Poisoning; Memory; Public Health; Rats; Tandem Mass Spectrometry; Spatial Learning
  3. Low PH, Mangat MS, Liew DNS, Wong ASH
    World Neurosurg, 2020 12;144:e710-e713.
    PMID: 32949798 DOI: 10.1016/j.wneu.2020.09.045
    BACKGROUND: The novel coronavirus disease 2019 (COVID-19) pandemic has set a huge challenge to the delivery of neurosurgical services, including the transfer of patients. We aimed to share our strategy in handling neurosurgical emergencies at a remote center in Borneo island. Our objectives included discussing the logistic and geographic challenges faced during the COVID-19 pandemic.

    METHODS: Miri General Hospital is a remote center in Sarawak, Malaysia, serving a population with difficult access to neurosurgical services. Two neurosurgeons were stationed here on a rotational basis every fortnight during the pandemic to handle neurosurgical cases. Patients were triaged depending on their urgent needs for surgery or transfer to a neurosurgical center and managed accordingly. All patients were screened for potential risk of contracting COVID-19 prior to the surgery. Based on this, the level of personal protective equipment required for the health care workers involved was determined.

    RESULTS: During the initial 6 weeks of the Movement Control Order in Malaysia, there were 50 urgent neurosurgical consultations. Twenty patients (40%) required emergency surgery or intervention. There were 9 vascular (45%), 5 trauma (25%), 4 tumor (20%), and 2 hydrocephalus cases (10%). Eighteen patients were operated at Miri General Hospital, among whom 17 (94.4%) survived. Ninety percent of anticipated transfers were avoided. None of the medical staff acquired COVID-19.

    CONCLUSIONS: This framework allowed timely intervention for neurosurgical emergencies (within a safe limit), minimized transfer, and enabled uninterrupted neurosurgical services at a remote center with difficult access to neurosurgical care during a pandemic.

    MeSH terms: Personal Protective Equipment; Borneo/epidemiology; Brain Neoplasms/surgery*; Emergencies*; Female; Craniocerebral Trauma/surgery*; Hospitals, General; Humans; Hydrocephalus/surgery*; Malaysia/epidemiology; Male; Neurosurgery*; Patient Transfer/statistics & numerical data*; Transportation of Patients; Triage; Air Ambulances; Skull Base Neoplasms/surgery; Neurosurgical Procedures/statistics & numerical data*; Central Nervous System Vascular Malformations/surgery
  4. Ibrahim Awad Mohammed, Abdallah Reghioua, Emad Yousif, Ali H. Jawad, Nurul Najwa Abd Malek
    Science Letters, 2020;14(1):96-108.
    MyJurnal
    Chitosan-epichlorohydrin/TiO2 composite was synthesized to be employed as an adsorbent for the
    removal of reactive red 4 (RR4) dye from aqueous solution. Response surface methodology (RSM) with 3-level Box-Behnken design (BBD) was utilized for the optimization of the removal of RR4. The process key variables which include adsorbent dose (A: 0.5 – 1.5 g), pH (B: 4 – 10) and time (30 – 80 min) were selected for the optimization process. The experimental data for RR4 removal were statistically analysed using analysis of variance (ANOVA). The significant interaction between key parameters on RR4 removal efficiency was observed by interaction between AB and AC. The highest RR4 removal (95.08%) was obtained under the following conditions; adsorbent dose (1.0 g), pH 4 and time of 80 min.
    MeSH terms: Analysis of Variance; Biometry; Epichlorohydrin; Hydrogen-Ion Concentration; Titanium; Water; Chitosan
  5. Nurul Najwa Abd Malek, Ali H. Jawad, Emad Yousif
    Science Letters, 2020;14(1):83-95.
    MyJurnal
    Cross-linked chitosan-epichlorohydrin was prepared for the adsorption of Reactive Red 4 (RR4).
    Response surface methodology (RSM) with 3–level Box-Behnken design (BBD) was employed to
    optimize the RR4 dye removal efficiency from aqueous solution. The adsorption key parameters that were selected such as adsorbent dose (A: 0.5 – 1.5 g), pH (B: 4 – 10) and time (30 – 80 min). The F-value of BBD model for RR4 removal efficiency was 185.36 (corresponding p-value < 0.0001). The results illustrated that the highest RR4 removal efficiency (70.53%) was obtained at the following conditions: adsorbent dose (1.0 g), pH 4 and time of 80 min.
    MeSH terms: Adsorption; Employment; Epichlorohydrin; Hydrogen-Ion Concentration; Water; Chitosan
  6. Nur Shazwani Abdul Mubarak, S. Sabar, Ali H. Jawad
    Science Letters, 2020;14(1):68-83.
    MyJurnal
    Commercial titanium dioxide Degussa P25 (TiO2) was used for the adsorption of reactive red 120
    (RR120) dye in a batch system. The optimization functions such as solution pH (3-12), adsorbent dosage (0.02 g-1.2 g), and initial dye concentration (30-400 mg/L) were studied. The equilibrium adsorption data for RR120 dye was analyzed by two types of isotherm models which are Langmuir and Freundlich models. The adsorption at equilibrium showed a better fit for linear Langmuir isotherm with the adsorption capacity, qmax of 18.62 mg/g at 303 K. The adsorption kinetic was well-described by pseudosecond order model. TiO2 showed a decent outcome due to the ability to adsorb target pollutants with theadded advantage of providing large hydroxyl groups (OH) on the surface of TiO2 so that pollutants can be adsorbed by interacting on the surface of OH.
    MeSH terms: Adsorption; Environmental Pollutants; Hydrogen-Ion Concentration; Kinetics; Titanium; Triazines
  7. Nur Afiqah Saparin, Mohd Muzamir Mahat, Muhd Fauzi Safian, Shahrul Hisham Zainal Ariffin, Nor Azah Mohamad Ali, Zaidah Zainal Ariffin
    Science Letters, 2020;14(1):62-67.
    MyJurnal
    The evolution of cosmetic products results in the growing demands for cosmetics that are preservatives free. Plant essential oils were found to be a promising antimicrobial and also antioxidant agent. In this study, Cymbopogon citratus (lemongrass), Laurus nobilis (bay leaf) and Backhousia citriodora (lemon myrtle) essential oils were selected and evaluated for their antimicrobial properties. It was found that Laurus nobilis exhibited strong antimicrobial activity against the selected bacteria Streptococcus saprophyticus (ATCC 49619), Streptococcus aureus (ATCC 22923), Streptococcus pyogenes (ATCC 29436), Pseudomonas aeruginosa (ATCC 13048), Klebsiella pneumoniae (ATCC 700603), Escherichia coli (ATCC 22922) with MIC ranging between 7.8 ug/mL to 250 μg/mL. The antioxidant activity of selected essential oils was determined by antioxidant assays which were 1,1-Diphenyl-2-picrylhydrazyl assay (DPPH), determination of ferric reducing antioxidant power assay (FRAP) and β-Carotene/linoleic acid bleaching assay. Backhousia citriodora and Laurus nobilis showed the highest antioxidant activity.
    n-Octanal and β-Selinene were identified to be the major components with peak area of 26.37 % and 13.92 % respectively in secondary metabolites analysis by Gas Chromatography-Mass Spectrometry (GCMS).
    MeSH terms: Antioxidants; Escherichia coli; Klebsiella pneumoniae; Gas Chromatography-Mass Spectrometry; Oils, Volatile; Pseudomonas aeruginosa; Streptococcus pyogenes; beta Carotene; Linoleic Acid; Laurus; Myrtus; Cymbopogon
  8. Johari MI, Yusoff K, Haron J, Nadarajan C, Ibrahim KN, Wong MS, et al.
    Sci Rep, 2020 Jun 25;10(1):10599.
    PMID: 32587371 DOI: 10.1038/s41598-020-67806-9
    An amendment to this paper has been published and can be accessed via a link at the top of the paper.
    MeSH terms: Humans
  9. Guo X, Sun C, Lin R, Xia A, Huang Y, Zhu X, et al.
    J Hazard Mater, 2020 11 15;399:122830.
    PMID: 32937692 DOI: 10.1016/j.jhazmat.2020.122830
    Stimulating direct interspecies electron transfer with conductive materials is a promising strategy to overcome the limitation of electron transfer efficiency in syntrophic methanogenesis of industrial wastewater. This paper assessed the impact of conductive foam nickel (FN) supplementation on syntrophic methanogenesis and found that addition of 2.45 g/L FN in anaerobic digestion increased the maximum methane production rate by 27.4 % (on day 3) while decreasing the peak production time by 33 % as compared to the control with no FN. Cumulative methane production from day 2 to 6 was 14.5 % higher with addition of 2.45 g/L FN than in the control. Levels of FN in excess of 2.45 g/L did not show benefits. Cyclic voltammetry results indicated that the biofilm formed on the FN could generate electrons. The dominant bacterial genera in suspended sludge were Dechlorobacter and Rikenellaceae DMER64, whereas that in the FN biofilm was Clostridium sensu stricto 11. The dominant archaea Methanosaeta in the FN biofilm was enriched by 14.1 % as compared to the control.
    MeSH terms: Anaerobiosis; Electron Transport; Electrons*; Methane*; Nickel; Sewage; Bioreactors; Dietary Supplements
  10. Lai CQ, Ibrahim H, Abd Hamid AI, Abdullah JM
    Sensors (Basel), 2020 Sep 14;20(18).
    PMID: 32937801 DOI: 10.3390/s20185234
    Traumatic brain injury (TBI) is one of the common injuries when the human head receives an impact due to an accident or fall and is one of the most frequently submitted insurance claims. However, it is often always misused when individuals attempt an insurance fraud claim by providing false medical conditions. Therefore, there is a need for an instant brain condition classification system. This study presents a novel classification architecture that can classify non-severe TBI patients and healthy subjects employing resting-state electroencephalogram (EEG) as the input, solving the immobility issue of the computed tomography (CT) scan and magnetic resonance imaging (MRI). The proposed architecture makes use of long short term memory (LSTM) and error-correcting output coding support vector machine (ECOC-SVM) to perform multiclass classification. The pre-processed EEG time series are supplied to the network by each time step, where important information from the previous time step will be remembered by the LSTM cell. Activations from the LSTM cell is used to train an ECOC-SVM. The temporal advantages of the EEG were amplified and able to achieve a classification accuracy of 100%. The proposed method was compared to existing works in the literature, and it is shown that the proposed method is superior in terms of classification accuracy, sensitivity, specificity, and precision.
    MeSH terms: Electroencephalography*; Humans; Magnetic Resonance Imaging; Tomography, X-Ray Computed; Support Vector Machine*
  11. Haque ST, Islam RA, Gan SH, Chowdhury EH
    Int J Mol Sci, 2020 Sep 14;21(18).
    PMID: 32937817 DOI: 10.3390/ijms21186721
    Background: The limitations of conventional treatment modalities in cancer, especially in breast cancer, facilitated the necessity for developing a safer drug delivery system (DDS). Inorganic nano-carriers based on calcium phosphates such as hydroxyapatite (HA) and carbonate apatite (CA) have gained attention due to their biocompatibility, reduced toxicity, and improved therapeutic efficacy. Methods: In this study, the potential of goose bone ash (GBA), a natural derivative of HA or CA, was exploited as a pH-responsive carrier to successfully deliver doxorubicin (DOX), an anthracycline drug into breast cancer cells (e.g., MCF-7 and MDA-MB-231 cells). GBA in either pristine form or in suspension was characterized in terms of size, morphology, functional groups, cellular internalization, cytotoxicity, pH-responsive drug (DOX) release, and protein corona analysis. Results: The pH-responsive drug release study demonstrated the prompt release of DOX from GBA through its disintegration in acidic pH (5.5-6.5), which mimics the pH of the endosomal and lysosomal compartments as well as the stability of GBA in physiological pH (pH 7.5). The result of DOX binding with GBA indicated an increment in binding affinity with increasing concentrations of DOX. Cell viability and cytotoxicity analysis showed no innate toxicity of GBA particles. Both qualitative and quantitative cellular uptake analysis in both cell lines displayed an enhanced cellular internalization of DOX-loaded GBA compared to free DOX molecules. The protein corona spontaneously formed on the surface of GBA particles exhibited its affinity toward transport proteins, structural proteins, and a few other selective proteins. The adsorption of transport proteins could extend the circulation half-life in biological environment and increase the accumulation of the drug-loaded NPs through the enhanced permeability and retention (EPR) effect at the tumor site. Conclusion: These findings highlight the potential of GBA as a DDS to successfully deliver therapeutics into breast cancer cells.
    MeSH terms: Biocompatible Materials/chemistry; Bone and Bones/chemistry*; Breast Neoplasms/drug therapy*; Calcium Phosphates/chemistry; Cell Survival/drug effects; Doxorubicin/pharmacology*; Doxorubicin/chemistry*; Drug Carriers/chemistry*; Female; Humans; Hydrogen-Ion Concentration; Permeability/drug effects; Drug Delivery Systems/methods; Anthracyclines/pharmacology; Cell Line, Tumor; Nanoparticles/chemistry*; MCF-7 Cells; Drug Liberation/drug effects
  12. Sani Haliru B, Rafii MY, Mazlan N, Ramlee SI, Muhammad I, Silas Akos I, et al.
    Plants (Basel), 2020 Sep 14;9(9).
    PMID: 32937908 DOI: 10.3390/plants9091202
    Brown planthopper (BPH; Nilaparvata lugens Stal) is considered the main rice insect pest in Asia. Several BPH-resistant varieties of rice have been bred previously and released for large-scale production in various rice-growing regions. However, the frequent surfacing of new BPH biotypes necessitates the evolution of new rice varieties that have a wide genetic base to overcome BPH attacks. Nowadays, with the introduction of molecular approaches in varietal development, it is possible to combine multiple genes from diverse sources into a single genetic background for durable resistance. At present, above 37 BPH-resistant genes/polygenes have been detected from wild species and indica varieties, which are situated on chromosomes 1, 3, 4, 6, 7, 8, 9, 10, 11 and 12. Five BPH gene clusters have been identified from chromosomes 3, 4, 6, and 12. In addition, eight BPH-resistant genes have been successfully cloned. It is hoped that many more resistance genes will be explored through screening of additional domesticated and undomesticated species in due course.
    MeSH terms: Genetic Background; Animals; Asia; Chromosomes, Human, Pair 3; Multigene Family; Hemiptera; Humans; Male; Prostatic Hyperplasia; Oryza
  13. Junaid M, Md Khir MH, Witjaksono G, Ullah Z, Tansu N, Saheed MSM, et al.
    Molecules, 2020 Sep 14;25(18).
    PMID: 32937975 DOI: 10.3390/molecules25184217
    In recent years, the field of nanophotonics has progressively developed. However, constant demand for the development of new light source still exists at the nanometric scale. Light emissions from graphene-based active materials can provide a leading platform for the development of two dimensional (2-D), flexible, thin, and robust light-emitting sources. The exceptional structure of Dirac's electrons in graphene, massless fermions, and the linear dispersion relationship with ultra-wideband plasmon and tunable surface polarities allows numerous applications in optoelectronics and plasmonics. In this article, we present a comprehensive review of recent developments in graphene-based light-emitting devices. Light emissions from graphene-based devices have been evaluated with different aspects, such as thermal emission, electroluminescence, and plasmons assisted emission. Theoretical investigations, along with experimental demonstration in the development of graphene-based light-emitting devices, have also been reviewed and discussed. Moreover, the graphene-based light-emitting devices are also addressed from the perspective of future applications, such as optical modulators, optical interconnects, and optical sensing. Finally, this review provides a comprehensive discussion on current technological issues and challenges related to the potential applications of emerging graphene-based light-emitting devices.
    MeSH terms: Electric Conductivity; Electrochemistry; Electrodes; Electronics; Electrons; Graphite/chemistry*; Light*; Temperature; Surface Plasmon Resonance/methods; Nanotechnology/methods*; Luminescence; Optics and Photonics; Optical Devices
  14. Algamal ZY, Qasim MK, Lee MH, Ali HTM
    SAR QSAR Environ Res, 2020 Nov;31(11):803-814.
    PMID: 32938208 DOI: 10.1080/1062936X.2020.1818616
    High-dimensionality is one of the major problems which affect the quality of the quantitative structure-activity relationship (QSAR) modelling. Obtaining a reliable QSAR model with few descriptors is an essential procedure in chemometrics. The binary grasshopper optimization algorithm (BGOA) is a new meta-heuristic optimization algorithm, which has been used successfully to perform feature selection. In this paper, four new transfer functions were adapted to improve the exploration and exploitation capability of the BGOA in QSAR modelling of influenza A viruses (H1N1). The QSAR model with these new quadratic transfer functions was internally and externally validated based on MSEtrain, Y-randomization test, MSEtest, and the applicability domain (AD). The validation results indicate that the model is robust and not due to chance correlation. In addition, the results indicate that the descriptor selection and prediction performance of the QSAR model for training dataset outperform the other S-shaped and V-shaped transfer functions. QSAR model using quadratic transfer function shows the lowest MSEtrain. For the test dataset, proposed QSAR model shows lower value of MSEtest compared with the other methods, indicating its higher predictive ability. In conclusion, the results reveal that the proposed QSAR model is an efficient approach for modelling high-dimensional QSAR models and it is useful for the estimation of IC50 values of neuraminidase inhibitors that have not been experimentally tested.
    MeSH terms: Algorithms*; Antiviral Agents/pharmacology*; Enzyme Inhibitors/chemistry*; Models, Chemical; Neuraminidase/antagonists & inhibitors*; Viral Proteins/antagonists & inhibitors*; Drug Design; Computational Biology; Quantitative Structure-Activity Relationship*; Influenza A Virus, H1N1 Subtype/enzymology*
  15. Kalaw E, Lim M, Kutasovic JR, Sokolova A, Taege L, Johnstone K, et al.
    Br J Cancer, 2020 11;123(11):1665-1672.
    PMID: 32939056 DOI: 10.1038/s41416-020-01065-3
    BACKGROUND: Metaplastic breast carcinoma encompasses a heterogeneous group of tumours with differentiation into squamous and/or spindle, chondroid, osseous or rhabdoid mesenchymal-looking elements. Emerging immunotherapies targeting Programmed Death Ligand 1 (PD-L1) and immune-suppressing T cells (Tregs) may benefit metaplastic breast cancer patients, which are typically chemo-resistant and do not express hormone therapy targets.

    METHODS: We evaluated the immunohistochemical expression of PD-L1 and FOXP3, and the extent of tumour infiltrating lymphocytes (TILs) in a large cohort of metaplastic breast cancers, with survival data.

    RESULTS: Metaplastic breast cancers were significantly enriched for PD-L1 positive tumour cells, compared to triple-negative ductal breast cancers (P 

    MeSH terms: Adult; Aged; Breast Neoplasms/immunology; Breast Neoplasms/pathology*; Female; Humans; Metaplasia; Middle Aged; Biomarkers, Tumor/immunology*; Lymphocytes, Tumor-Infiltrating/immunology; Forkhead Transcription Factors/biosynthesis*; Antigens, CD274/biosynthesis*
  16. Haditiar Y, Putri MR, Ismail N, Muchlisin ZA, Ikhwan M, Rizal S
    Heliyon, 2020 Sep;6(9):e04828.
    PMID: 32939416 DOI: 10.1016/j.heliyon.2020.e04828
    Malacca Strait (MS) has an important role and potential for many countries. It is a major transportation route for oil and commodities across continents. In addition, various activities such as shipping, fishing, aquaculture, oil drilling, and energy are also carried out in MS. Tides strongly affect the MS environment so that it becomes a major parameter in MS management. This paper is the first study, which presents MS tidal hydrodynamics based on a baroclinic and nonhydrostatic approach. Tidal hydrodynamics in MS and the surrounding waters were assessed using tidal forces, temperature, salinity, and density. This study analyzes the amplitude, phase, current ellipses, and semi-major axis of the tides. These variables are obtained from the simulation results of the three-dimensional numerical models of M2 tides and combined tides (M2, S2, N2, K1, and O1) with nonhydrostatic models. Then the results obtained are verified by observation data. Amplitude and phase of the tidal wave in MS originate from two directions, namely the northern part of MS (Andaman Sea) and the South China Sea (SCS). Tides from the north of MS propagate into the MS, while tides from the SCS travel to Singapore Waters (SW) and the south of MS. This causes a complex residual flow in SW and shoaling in the middle of MS. Shoaling in the middle of MS is characterized by a large amplitude and semi-major, as in B. Siapiapi. The results of this analysis show that tidal waves are dominated by semidiurnal types rather than diurnal types. The M2 current ellipse has dominantly anticlockwise rotation along the west of the MS, while along the east of MS, it has generally a clockwise rotation.
    MeSH terms: China; Reproduction; Rotation; Singapore; Temperature; Transportation; Aquaculture; Salinity; Physical Phenomena; Tidal Waves; Hydrodynamics
  17. Pourshahrestani S, Zeimaran E, Kadri NA, Mutlu N, Boccaccini AR
    Adv Healthc Mater, 2020 10;9(20):e2000905.
    PMID: 32940025 DOI: 10.1002/adhm.202000905
    Broad interest in developing new hemostatic technologies arises from unmet needs in mitigating uncontrolled hemorrhage in emergency, surgical, and battlefield settings. Although a variety of hemostats, sealants, and adhesives are available, development of ideal hemostatic compositions that offer a range of remarkable properties including capability to effectively and immediately manage bleeding, excellent mechanical properties, biocompatibility, biodegradability, antibacterial effect, and strong tissue adhesion properties, under wet and dynamic conditions, still remains a challenge. Benefiting from tunable mechanical properties, high porosity, biocompatibility, injectability and ease of handling, polymeric hydrogels with outstanding hemostatic properties have been receiving increasing attention over the past several years. In this review, after shedding light on hemostasis and wound healing processes, the most recent progresses in hydrogel systems engineered from natural and synthetic polymers for hemostatic applications are discussed based on a comprehensive literature review. Most studies described used in vivo models with accessible and compressible wounds to assess the hemostatic performance of hydrogels. The challenges that need to be tackled to accelerate the translation of these novel hemostatic hydrogel systems to clinical practice are emphasized and future directions for research in the field are presented.
    MeSH terms: Biocompatible Materials*; Hemostasis; Polymers; Wound Healing; Hydrogels*
  18. Li Z, Gopinath SCB, Lakshmipriya T, Anbu P, Perumal V, Wang X
    Biomed Microdevices, 2020 Sep 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.
    MeSH terms: DNA/analysis; DNA/chemistry; Female; Humans; Biosensing Techniques/instrumentation; Papillomavirus E7 Proteins/genetics; Papillomavirus E7 Proteins/metabolism; Human papillomavirus 16/genetics; Lab-On-A-Chip Devices; Limit of Detection
  19. Woon KL, Mustapa SAS, Mohd Jamel NS, Lee VS, Zakaria MZ, Ariffin A
    Chemphyschem, 2020 Sep 17.
    PMID: 32940952 DOI: 10.1002/cphc.202000612
    Material designs that use donor and acceptor units are often found in organic optoelectronic devices. Molecular level insight into the interactions between donors and acceptors are crucial for understanding how such interactions can modify the optical properties of the organic optoelectronic materials. In this paper, tris(4-(tert-butyl)phenyl)amine (pTPA) was synthesized as a donor in order to compare with unmodified triphenylamine (TPA) in a donor-acceptor system by having 2,4,6-triphenyl-1,3,5-triazine (TRZ) as an acceptor. Dimerization of donors and acceptors occurred in solvent when the concentration of solute is high. At 0 K, using a polarizable continuum model, the nitrogen atom of TPA is found to stack on top of the center of triazine of TRZ, whereas such alignment is offset in pTPA and TRZ. We attributed such alignment in TPA-TRZ as the result of attractive interactions between partial localization of 2pz electrons at the nitrogen atom of TPA and the π deficiency of triazine in TPA-TRZ. By taking into account random motions of the solvent effect at 300 K in quantum molecular dynamics and classical molecular dynamics simulations to interpret the marked difference in emission spectra between TPA-TRZ and pTPA-TRZ, it was revealed that the attractive interaction between pTPA and TRZ in toluene is weaker than TPA and TRZ. Because of the weaker attractive interaction between pTPA and TRZ in toluene, the dimers adopted numerous ground state conformations resulting in broad emission bands superimposed with multiple small Gaussian peaks. This is in contrast to TPA-TRZ which has only one dominant dimer conformation. This study demonstrates that the strength of intermolecular interactions between donors and acceptors should be taken into consideration in designing supramolecular structures.
    MeSH terms: Amines; Electrons; Molecular Conformation; Nitrogen; Solutions; Solvents; Toluene; Triazines; Dimerization; Molecular Dynamics Simulation
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