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Fulltext Molecular genetic analysis of a supratentorial haemangioblastoma in a non-Von Hippel Lindau patient

Zamzuri I, Ghazali MM, Zainuddin N, Sulong S, Samarendra SM, Yusoff AAM, et al.

Med J Malaysia, 2005 Aug;60(3):360-3.
PMID: 16379193

We describe a rare tumor site in a 46 year old man who presented with a two week history of headache. Physical examination revealed bilateral papilloedema with no other localizing signs. Computed Tomographic Scan as well as Magnetic Resonance Imaging of the brain revealed a lesion with a dura tail located adjacent to the falx cerebri of the right frontal lobe. This lesion was not invading the inner table of the skull base. A tumor blush was seen on angiogram. There were no abnormalities on CT scan of the abdomen and fundoscopy was normal. Intraoperatively a vascular tumor not attached to the dura was noted and removed totally. Histopathological examination was typical of a hemangioblastoma. Analysis revealed no mutations of the VHL gene in 5 regions, exon 5-8 of the p53 gene, exon 1-2 of the p16 gene and exon 5,6 and 8 of the PTEN gene. This is the first case report of a supratentorial hemangioblastoma in a non-Von Hippel Lindau patient with genetic evidence.
Fulltext Third ventricular cavernous angioma

Zakaria MA, Abdullah JM, George JP, Mutum SS, Lee NN

Med J Malaysia, 2006 Jun;61(2):229-32.
PMID: 16898318 MyJurnal

Third ventricular cavernous angiomas are rare vascular malformations of the brain. We report an eight-year old boy with a rare third ventricular cavernous angioma that hemorrhaged presenting with symptoms of acute hydrocephalus. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) showed a heterogenous ill-defined, solid and cystic intraventricular mass in the third ventricle which was mildly enhanced with contrast and there was associated hydrocephalus. The mass was removed with success and follow up after two years revealed no neurological abnormalities.
CT scan in minor head injury: a guide for rural doctors

Abdul Latip LS, Ahmad Alias NA, Ariff AR, Shuaib IL, Abdullah J, Naing NN

J Clin Neurosci, 2004 Nov;11(8):835-9.
PMID: 15519858 DOI: 10.1016/j.jocn.2003.12.017

Minor head injury in a developing country like Malaysia is managed by primary care physicians and/or medical assistants in district hospitals. These patients are seen initially in their local hospitals, which have at least an X-ray machine for the purpose of screening. This study aimed to guide these physicians to manage these patients at a primary care level. A cross-sectional study was conducted and the study revealed significant predictors of significant computed tomographic (CT) findings. The presence of a Glasgow coma scale (GCS) score of 14 or 13 was associated with the risk of developing significant CT findings compared to patients with a GCS of 15 (p<0.001). Thirty-seven out of 50 patients with GCS of 14 or 13 developed clinically significant brain injury on CT scan. Similarly, the presence of skull fracture was associated with the risk of developing CT abnormalities (p<0.001). Forty-two out of 51 patients with skull fracture developed clinically significant CT findings. Vomiting was associated with developing CT abnormalities (p=0.017). Twenty-seven out of 40 patients with vomiting showed significant CT findings. Soft tissue injury was also found to be associated with developing CT abnormalities (p=0.007). Therefore, we propose reclassifying minor head injury based on the GCS score. Patients with a GCS score of 15 were classified as having mild head injury, while patients with a GCS score of 13 or 14 were at higher risk of developing brain injury and therefore categorized as high risk mild head injury. This group requires emergency CT scan examination, especially when associated with non-motor vehicle accidents, abnormal central nervous system (CNS) examination, craniofacial injuries or skull fractures. They should be referred to a general surgical unit which can treat head injuries or a neurosurgical tertiary centre.
Giant nerve sheath tumour: report of six cases

Ghani AR, Ariff AR, Romzi AR, Sayuthi S, Hasnan J, Kaur G, et al.

Clin Neurol Neurosurg, 2005 Jun;107(4):318-24.
PMID: 15885392

Giant nerve sheath tumour is a rare tumour originating from the nerve sheath. It differs from the conventional nerve sheath tumour only by the size these tumours can reach. There are two main type of tumours that occur in the nerve sheath which include neurofibroma and schwannoma. The current views are that schwannomas arise from the progenitor of the schwann cell. Whereas the neurofibroma series probably arise from a mesenchymal origin closer to a fibroblast. We report on six cases of nerve sheath tumour that occur in the spinal and paraspinal region that presented to us over a 5 year period.
Micromechanical modelling of oil palm empty fruit bunch fibres containing silica bodies

Omar FN, Hanipah SH, Xiang LY, Mohammed MAP, Baharuddin AS, Abdullah J

J Mech Behav Biomed Mater, 2016 09;62:106-118.
PMID: 27183430 DOI: 10.1016/j.jmbbm.2016.04.043

Experimental and numerical investigation was conducted to study the micromechanics of oil palm empty fruit bunch fibres containing silica bodies. The finite viscoelastic-plastic material model called Parallel Rheological Network model was proposed, that fitted well with cyclic and stress relaxation tensile tests of the fibres. Representative volume element and microstructure models were developed using finite element method, where the models information was obtained from microscopy and X-ray micro-tomography analyses. Simulation results showed that difference of the fibres model with silica bodies and those without ones is larger under shear than compression and tension. However, in comparison to geometrical effect (i.e. silica bodies), it is suggested that ultrastructure components of the fibres (modelled using finite viscoelastic-plastic model) is responsible for the complex mechanical behaviour of oil palm fibres. This can be due to cellulose, hemicellulose and lignin components and the interface behaviour, as reported on other lignocellulosic materials.
Fulltext Study on the spectrophotometric detection of free fatty acids in palm oil utilizing enzymatic reactions

Azeman NH, Yusof NA, Abdullah J, Yunus R, Hamidon MN, Hajian R

Molecules, 2015;20(7):12328-40.
PMID: 26198220 DOI: 10.3390/molecules200712328

In this paper, a comprehensive study has been made on the detection of free fatty acids (FFAs) in palm oil via an optical technique based on enzymatic aminolysis reactions. FFAs in crude palm oil (CPO) were converted into fatty hydroxamic acids (FHAs) in a biphasic lipid/aqueous medium in the presence of immobilized lipase. The colored compound formed after complexation between FHA and vanadium (V) ion solution was proportional to the FFA content in the CPO samples and was analyzed using a spectrophotometric method. In order to develop a rapid detection system, the parameters involved in the aminolysis process were studied. The utilization of immobilized lipase as catalyst during the aminolysis process offers simplicity in the product isolation and the possibility of conducting the process under extreme reaction conditions. A good agreement was found between the developed method using immobilized Thermomyces lanuginose lipase as catalyst for the aminolysis process and the Malaysian Palm Oil Board (MPOB) standard titration method (R2 = 0.9453).
Uniaxial and Multiaxial Fatigue Life Prediction of the Trabecular Bone Based on Physiological Loading: A Comparative Study

Fatihhi SJ, Harun MN, Abdul Kadir MR, Abdullah J, Kamarul T, Öchsner A, et al.

Ann Biomed Eng, 2015 Oct;43(10):2487-502.
PMID: 25828397 DOI: 10.1007/s10439-015-1305-8

Fatigue assessment of the trabecular bone has been developed to give a better understanding of bone properties. While most fatigue studies are relying on uniaxial compressive load as the method of assessment, in various cases details are missing, or the uniaxial results are not very realistic. In this paper, the effect of three different load histories from physiological loading applied on the trabecular bone were studied in order to predict the first failure surface and the fatigue lifetime. The fatigue behaviour of the trabecular bone under uniaxial load was compared to that of multiaxial load using a finite element simulation. The plastic strain was found localized at the trabecular structure under multiaxial load. On average, applying multiaxial loads reduced more than five times the fatigue life of the trabecular bone. The results provide evidence that multiaxial loading is dominated in the low cycle fatigue in contrast to the uniaxial one. Both bone volume fraction and structural model index were best predictors of failure (p
Computed tomography of the brain in predicting outcome of traumatic intracranial haemorrhage in Malaysian patients

Azian AA, Nurulazman AA, Shuaib L, Mahayidin M, Ariff AR, Naing NN, et al.

Acta Neurochir (Wien), 2001;143(7):711-20.
PMID: 11534693

Head injury is a significant economic, social and medical problem all over the world. Road accidents are the most frequent cause of head injury in Malaysia with highest risk in the young (15 to 24 years old). The associated outcomes include good recovery, possibility of death for the severely injured, which may cause disruption of the lives of their family members. It is important to predict the outcome as it will provide sound information to assist clinicians in Malaysia in providing prognostic information to patients and their families, to assess the effectiveness of different modes of treatment in promoting recovery and to document the significance of head injury as a public health problem.
RESULTS: A total of 103 cases with intracranial haemorrhage i.e. intracerebral haemorrhage, extradural haemorrhage, subdural haemorrhage, intraventricular haemorrhage, haemorrhagic contusion and subarachnoid haemorrhage, following motor vehicle accidents was undertaken to study factors contributing to either good or poor outcome according to the Glasgow Outcome Scale. Patients below 12 years of age were excluded. The end point of the study was taken at 24 months post injury. The selected variables were incorporated into models generated by logistic regression techniques of multivariate analysis to see the significant predictors of outcome as well as the correlation between the CT findings with GCS.
CONCLUSION: Significant predictors of outcome were GCS on arrival in the accident emergency department, pupillary reflex and the CT scan findings. The CT predictors of outcome include ICH, EDH, IVH, present of SAH, site of ICH, volumes of EDH and SDH as well as midline shift.
Association of p53 tumor suppressor gene with paraclinical and clinical modalities of gliomas patients in Malaysia

Yusoff AA, Abdullah J, Abdullah MR, Mohd Ariff AR, Isa MN

Acta Neurochir (Wien), 2004 Jun;146(6):595-601.
PMID: 15168228

Alteration of the tumor suppressor gene p53 is considered to be a critical step in the development of human cancer. Changes in this gene have been detected in a wide range of human tumours, including gliomas. In glioma, the presence of p53 gene alterations has been associated with worse prognosis.
The use of magnetic resonance phase-contrast cine in Chiari malformation with syringomyelia

Goh CH, Hamzah MR, Kandasamy R, Ghani ARI, Wong SH, Idris Z, et al.

Med J Malaysia, 2020 11;75(6):666-671.
PMID: 33219175

INTRODUCTION: Chiari malformation (CM) is a disorder of mesodermal origin and is commonly associated with syringomyelia. Foramen magnum decompression is the first-line of standard treatment in symptomatic patients with a confirmed radiographic diagnosis. Magnetic resonance (MR) cine allows accurate evaluation of cerebrospinal fluid (CSF) physiology at the craniovertebral junction but often this is under-utilised in Malaysia.
METHODS: In this series, we looked into nine cases of CM with syringomyelia from clinical and radiological perspective before and after surgery. The radiological parameters were herniated tonsillar length, syrinx: cord ratio, syrinx length and diameter. Flow velocity and morphologic changes in Chiari were illustrated.
RESULTS: Seven patients showed either reduction in syrinx length, syrinx: cord ratio or both postoperatively. Clinical recovery somewhat varied in motor and sensory symptoms. Four patients gained better functional grade in modified Rankin scale (MRS) while the rest remained similar. The study highlighted the advantage of CSF flow dynamics information over MR anatomical radiographic improvement in addressing the neurologic and functional recovery. We also discussed the practicality of cine sequence in preoperative patient selection, syrinx analysis and postoperative flow evaluation in anticipation of clinical outcome.
CONCLUSION: Phase-contrast cine MRI is a useful tool dictated by resource availability. We recommend its routine use in preoperative analysis and subsequent observational follow-up after surgery.
Label-free optical spectroscopy for characterizing binding properties of highly sensitive nanocrystalline cellulose-graphene oxide based nanocomposite towards nickel ion

Daniyal WMEMM, Fen YW, Abdullah J, Sadrolhosseini AR, Saleviter S, Omar NAS

Spectrochim Acta A Mol Biomol Spectrosc, 2019 Apr 05;212:25-31.
PMID: 30594850 DOI: 10.1016/j.saa.2018.12.031

Surface plasmon resonance (SPR) is a label-free optical spectroscopy that is widely used for biomolecular interaction analysis. In this work, SPR was used to characterize the binding properties of highly sensitive nanocrystalline cellulose-graphene oxide based nanocomposite (CTA-NCC/GO) towards nickel ion. The formation of CTA-NCC/GO nanocomposite has been confirmed by FT-IR. The SPR analysis result shows that the CTA-NCC/GO has high binding affinity towards Ni2+ from 0.01 until 0.1 ppm with binding affinity constant of 1.620 × 103 M-1. The sensitivity for the CTA-NCC/GO calculated was 1.509° ppm-1. The full width at half maximum (FWHM), data accuracy (DA), and signal-to-noise ratio (SNR) have also been determined using the obtained SPR curve. For the FWHM, the value was 2.25° at 0.01 until 0.08 ppm and decreases to 2.12° at 0.1 until 10 ppm. The DA for the SPR curves is the highest at 0.01 until 0.08 ppm and lowest at 0.1 until 10 ppm. The SNR curves mirrors the curves of SPR angle shift where the SNR increases with the Ni2+ concentrations. For the selectivity test, the CTA-NCC/GO has the abilities to differentiate Ni2+ in the mixture of metal ions.
Fulltext Malaysian Carica papaya L. var. Eksotika: Current Research Strategies Fronting Challenges

Sekeli R, Hamid MH, Razak RA, Wee CY, Ong-Abdullah J

Front Plant Sci, 2018;9:1380.
PMID: 30279695 DOI: 10.3389/fpls.2018.01380

Carica papaya L. or commonly known as papaya, is a major tropical crop consumed worldwide either as a vegetable or fresh fruit or processed products. In Malaysia, papaya was initially planted as a smallholder crop throughout the country. Eventually after 15 years of breeding and selection, a new variety, named C. papaya L. var. Eksotika, was released by the Malaysian Agricultural Research and Development Institute (MARDI) in 1987. This event changed the outlook of papaya planting from a smallholder crop to a plantation crop. Despite the blooming papaya business, the industry faced various disease issues that jeopardize its future. The most devastating was the papaya dieback disease, which affected approximately 800 hectares of plantation, destroyed approximately 1 million trees nationwide with total losses estimated at US$ 58 million. Even though Eksotika is a favored commercial variety with good eating and aesthetic quality fruit, its potential for more lucrative distant markets is tarnished with its short-shelf life fruits. Several strategies had been reported to address the challenges faced by Eksotika specifically against the dieback disease and the fruit's short shelf-life. This review focuses on C. papaya L. var. Eksotika particularly on the strategies to address the challenges faced in order to sustain the economic value of this crop plant, which had contributed significantly to the Malaysian economy.
Fluorescence-based immunoassay for the detection of Xanthomonas oryzae pv. oryzae in rice leaf

Awaludin N, Abdullah J, Salam F, Ramachandran K, Yusof NA, Wasoh H

Anal Biochem, 2020 12 01;610:113876.
PMID: 32750357 DOI: 10.1016/j.ab.2020.113876

The identification of rice bacterial leaf blight disease requires a simple, rapid, highly sensitive, and quantitative approach that can be applied as an early detection monitoring tool in rice health. This paper highlights the development of a turn-off fluorescence-based immunoassay for the early detection of Xanthomonas oryzae pv. oryzae (Xoo), a gram-negative bacterium that causes rice bacterial leaf blight disease. Antibodies against Xoo bacterial cells were produced as specific bio-recognition molecules and the conjugation of these antibodies with graphene quantum dots and gold nanoparticles was performed and characterized, respectively. The combination of both these bio-probes as a fluorescent donor and metal quencher led to changes in the fluorescence signal. The immunoreaction between AntiXoo-GQDs, Xoo cells, and AntiXoo-AuNPs in the immuno-aggregation complex led to the energy transfer in the turn-off fluorescence-based quenching system. The change in fluorescence intensity was proportional to the logarithm of Xoo cells in the range of 100-105 CFU mL-1. The limit of detection was achieved at 22 CFU mL-1 and the specificity test against other plant disease pathogens showed high specificity towards Xoo. The detection of Xoo in real plant samples was also performed in this study and demonstrated satisfactory results.
Fulltext Comprehensive analysis of mutations and clonal evolution patterns in a cohort of patients with cytogenetically normal acute myeloid leukemia

Mat Yusoff Y, Ahid F, Abu Seman Z, Abdullah J, Kamaluddin NR, Esa E, et al.

Mol Cytogenet, 2021 Sep 24;14(1):45.
PMID: 34560908 DOI: 10.1186/s13039-021-00561-2

BACKGROUND: Relapsed acute myeloid leukemia (AML) is associated with the acquisition of additional somatic mutations which are thought to drive phenotypic adaptability, clonal selection and evolution of leukemic clones during treatment. We performed high throughput exome sequencing of matched presentation and relapsed samples from 6 cytogenetically normal AML (CN-AML) patients treated with standard remission induction chemotherapy in order to contribute with the investigation of the mutational landscape of CN-AML and clonal evolution during AML treatment.
RESULT: A total of 24 and 32 somatic variants were identified in presentation and relapse samples respectively with an average of 4.0 variants per patient at presentation and 5.3 variants per patient at relapse, with SNVs being more frequent than indels at both disease stages. All patients have somatic variants in at least one gene that is frequently mutated in AML at both disease presentation and relapse, with most of these variants are classic AML and recurrent hotspot mutations including NPM1 p.W288fs, FLT3-ITD, NRAS p.G12D and IDH2 p.R140Q. In addition, we found two distinct clonal evolution patterns of relapse: (1) a leukemic clone at disease presentation acquires additional mutations and evolves into the relapse clone after the chemotherapy; (2) a leukemic clone at disease presentation persists at relapse without the addition of novel somatic mutations.
CONCLUSIONS: The findings of this study suggest that the relapse-initiating clones may pre-exist prior to therapy, which harbor or acquire mutations that confer selective advantage during chemotherapy, resulting in clonal expansion and eventually leading to relapse.
Corrigendum to "Biosynthesis of agar in red seaweeds: A review" [Carbohydr. Polym. 164 (2017) 23-30]

Lee WK, Lim YY, Leow AT, Namasivayam P, Ong Abdullah J, Ho CL

Carbohydr Polym, 2017 08 01;169:533.
PMID: 28504177 DOI: 10.1016/j.carbpol.2017.03.085
Fulltext Immuno Nanosensor for the Ultrasensitive Naked Eye Detection of Tuberculosis

Mohd Bakhori N, Yusof NA, Abdullah J, Wasoh H, Md Noor SS, Ahmad Raston NH, et al.

Sensors (Basel), 2018 Jun 14;18(6).
PMID: 29899214 DOI: 10.3390/s18061932

In the present study, a beneficial approach for the ultrasensitive and affordable naked eye detection and diagnosis of tuberculosis (TB) by utilizing plasmonic enzyme-linked immunosorbent assay (ELISA) via antibody-antigen interaction was studied. Here, the biocatalytic cycle of the intracellular enzymes links to the formation and successive growth of the gold nanoparticles (GNPs) for ultrasensitive detection. The formation of different colored solutions by the plasmonic nanoparticles in the presence of enzyme labels links directly to the existence or non-existence of the TB analytes in the sample solutions. For disease detection, the adapted protocol is based mainly on the conventional ELISA procedure that involves catalase-labeled antibodies, i.e., the enzymes consume hydrogen peroxide and further produce GNPs with the addition of gold (III) chloride. The amount of hydrogen peroxide remaining in the solution determines whether the GNPs solution is to be formed in the color blue or the color red, as it serves as a confirmation for the naked eye detection of TB analytes. However, the conventional ELISA method only shows tonal colors that need a high concentration of analyte to achieve high confidence levels for naked eye detection. Also, in this research, we proposed the incorporation of protein biomarker, Mycobacterium tuberculosis ESAT-6-like protein esxB (CFP-10), as a means of TB detection using plasmonic ELISA. With the use of this technique, the CFP-10 detection limit can be lowered to 0.01 µg/mL by the naked eye. Further, our developed technique was successfully tested and confirmed with sputum samples from patients diagnosed with positive TB, thereby providing enough evidence for the utilization of our technique in the early diagnosis of TB disease.
Biosynthesis of agar in red seaweeds: A review

Lee WK, Lim YY, Leow AT, Namasivayam P, Ong Abdullah J, Ho CL

Carbohydr Polym, 2017 May 15;164:23-30.
PMID: 28325321 DOI: 10.1016/j.carbpol.2017.01.078

Agar is a jelly-like biopolymer synthesized by many red seaweeds as their major cell wall component. Due to its excellent rheological properties, it has been exploited commercially for applications in food, cosmetic, pharmaceutical, biomedical and biotechnology industries. Despite its multiple uses, the biosynthesis of this phycocolloid is not fully understood. The current knowledge on agar biosynthesis is inferred from plant biochemistry and putative pathways for ulvan and alginate biosynthesis in green and brown seaweeds, respectively. In this review, the gaps in our current knowledge on agar biosynthetic pathway are discussed, focusing on the biosynthesis of agar precursors, elongation of agar polysaccharide chain and side chain modification. The development of molecular markers for the screening of desired seaweeds for industrial exploitation is also discussed.
A systematic review of the computerized tools and digital techniques applied to fabricate nasal, auricular, orbital and ocular prostheses for facial defect rehabilitation

Farook TH, Jamayet NB, Abdullah JY, Rajion ZA, Alam MK

J Stomatol Oral Maxillofac Surg, 2020 Jun;121(3):268-277.
PMID: 31610244 DOI: 10.1016/j.jormas.2019.10.003

A systematic review was conducted in early 2019 to evaluate the articles published that dealt with digital workflow, CAD, rapid prototyping and digital image processing in the rehabilitation by maxillofacial prosthetics. The objective of the review was to primarily identify the recorded cases of orofacial rehabilitation made by maxillofacial prosthetics using computer assisted 3D printing. Secondary objectives were to analyze the methods of data acquisition recorded with challenges and limitations documented with various software in the workflow. Articles were searched from Scopus, PubMed and Google Scholar based on the predetermined eligibility criteria. Thirty-nine selected papers from 1992 to 2019 were then read and categorized according to type of prosthesis described in the papers. For nasal prostheses, Common Methods of data acquisition mentioned were computed tomography, photogrammetry and laser scanners. After image processing, computer aided design (CAD) was used to design and merge the prosthesis to the peripheral healthy tissue. Designing and printing the mold was more preferred. Moisture and muscle movement affected the overall fit especially for prostheses directly designed and printed. For auricular prostheses, laser scanning was most preferred. For unilateral defects, CAD was used to mirror the healthy tissue over to the defect side. Authors emphasized on the need of digital library for prostheses selection, especially for bilateral defects. Printing the mold and conventionally creating the prosthesis was most preferred due to issues of proper fit and color matching. Orbital prostheses follow a similar workflow as auricular prosthesis. 3D photogrammetry and laser scans were more preferred and directly printing the prosthesis was favored in various instance. However, ocular prostheses fabrication was recorded to be a challenge due to difficulties in appropriate volume reconstruction and inability to mirror healthy globe. Only successful cases of digitally designed and printed iris were noted.
A fluorescence quenching based gene assay for Escherichia coli O157:H7 using graphene quantum dots and gold nanoparticles

Saad SM, Abdullah J, Rashid SA, Fen YW, Salam F, Yih LH

Mikrochim Acta, 2019 11 19;186(12):804.
PMID: 31745737 DOI: 10.1007/s00604-019-3913-8

A fluorometric assay is described for highly sensitive quantification of Escherichia coli O157:H7. Reporter oligos were immobilized on graphene quantum dots (GQDs), and quencher oligos were immobilized on gold nanoparticles (AuNPs). Target DNA was co-hybridized with reporter oligos on the GQDs and quencher oligos on AuNPs. This triggers quenching of fluorescence (with excitation/emission peaks at 400 nm/530 nm). On introducing target into the system, fluorescence is quenched by up to 95% by 100 nM concentrations of target oligos having 20 bp. The response to the fliC gene of E. coli O157:H7 increases with the logarithm of the concentration in the range from 0.1 nM to 150 nM. The limit of detection is 1.1 ± 0.6 nM for n = 3. The selectivity and specificity of the assay was confirmed by evaluating the various oligos sequences and PCR product (fliC gene) amplified from genomic DNA of the food samples spiked with E. coli O157:H7. Graphical abstractSchematic representation of fluorometric assay for highly sensitive quantification of Escherichia coli O157:H7 based on fluorescence quenching gene assay for fliC gene of E. coli O157:H7.
Nanocrystalline cellulose decorated quantum dots based tyrosinase biosensor for phenol determination

Manan FAA, Hong WW, Abdullah J, Yusof NA, Ahmad I

Mater Sci Eng C Mater Biol Appl, 2019 Jun;99:37-46.
PMID: 30889711 DOI: 10.1016/j.msec.2019.01.082

Novel biosensor architecture based on nanocrystalline cellulose (NCC)/CdS quantum dots (QDs) nanocomposite was developed for phenol determination. This nanocomposite was prepared with slight modification of nanocrystalline cellulose (NCC) with cationic surfactant of cetyltriammonium bromide (CTAB) and further decorated with 3-mercaptopropionic acid (3-MPA) capped CdS QDs. The nanocomposite material was then employed as scaffold for immobilization of tyrosinase enzyme (Tyr). The electrocatalytic response of Tyr/CTAB-NCC/QDs nanocomposite towards phenol was evaluated using differential pulse voltammetry (DPV). The current response obtained is proportional to the concentration of phenol which attributed to the reduction of o-quinone produced at the surface of the modified electrode. Under the optimal conditions, the biosensor exhibits good linearity towards phenol in the concentration range of 5-40 μM (R2 = 0.9904) with sensitivity and limit of detection (LOD) of 0.078 μA/μM and 0.082 μM, respectively.

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