Chitosan-based tyrosinase optical phenol biosensor employing hybrid nafion/sol–gel silicate for MBTH immobilization

Abdullah, Jaafar; Ahmad, Musa; Heng, Lee Yook; Karuppiah, N.; Sidek, Hamidah

doi:10.1016/j.talanta.2005.12.061

Cited by 55 publications

(19 citation statements)

References 25 publications

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“…In addition to the glucose detection, we applied the photoluminescent peptide hydrogel by encapsulating HRP for the detection of toxic pollutants such as phenol and hydroquinone that cause harmful effects on human health and the environment (Gianfreda et al, 2006;Abdullah et al, 2006). Phenol and hydroquinone are known to be converted to quinone intermediates through a HRP-catalyzed reaction, and the intermediates perform the role of electron acceptors (i.e., quenching agent) on the surface of QDs (Yuan et al, 2008).…”

Section: Resultsmentioning

confidence: 99%

Self-assembled, photoluminescent peptide hydrogel as a versatile platform for enzyme-based optical biosensors

Kim

Lim

Nam

et al. 2011

Biosensors and Bioelectronics

119

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Section: Resultsmentioning

confidence: 99%

Self-assembled, photoluminescent peptide hydrogel as a versatile platform for enzyme-based optical biosensors

Kim

Lim

Nam

et al. 2011

Biosensors and Bioelectronics

119

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“…Biosensors can provide rapid measurement without labor-intensive and time-consuming sample preparation and apparently allow for a promising way to assess the biologically available phenol in the environment. Previously, different biosensors for phenol have been described such as the amperometric [4], [5], enzymatic [6], and optical biosensor [7].…”

Section: Introductionmentioning

confidence: 99%

An Effective Strategy for a Whole-Cell Biosensor Based on Putative Effector Interaction Site of the Regulatory DmpR Protein

et al. 2012

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Introduction and RationaleThe detection of bioavailable phenol is a very important issue in environmental and human hazard assessment. Despite modest developments recently, there is a stern need for development of novel biosensors with high sensitivity for priority phenol pollutants. DmpR (Dimethyl phenol regulatory protein), an NtrC-like regulatory protein for the phenol degradation of Pseudomonas sp. strain CF600, represents an attractive biosensor regimen. Thus, we sought to design a novel biosensor by modifying the phenol detection capacity of DmpR by using mutagenic PCR.MethodsBinding sites of ‘A’ domain of DmpR were predicted by LIGSITE, and molecular docking was performed by using GOLD to identify the regions where phenol may interact with DmpR. Total five point mutations, one single at position 42 (Phe-to-Leu), two double at 140 (Asp-to-Glu) and 143 (Gln-to-Leu), and two double at L113M (Leu-to- Met) and D116A (Asp-to- Ala) were created in DmpR by site-directed mutagenesis to construct the reporter plasmids pRLuc42R, pRLuc140p143R, and pRLuc113p116R, respectively. Luciferase assays were performed to measure the activity of luc gene in the presence of phenol and its derivatives, while RT-PCR was used to check the expression of luc gene in the presence of phenol.ResultsOnly pRLuc42R and pRLuc113p116R showed positive responses to phenolic effectors. The lowest detectable concentration of phenol was 0.5 µM (0.047 mg/L), 0.1 µM for 2, 4-dimethylphenol and 2-nitrophenol, 10 µM for 2, 4, 6-trichlorophenol and 2-chlorophenol, 100 µM for 2, 4-dichlorophenol, 0.01 µM for 4-nitrophenol, and 1 µM for o-cresol. These concentrations were measured by modified luciferase assay within 3 hrs compared to 6–7 hrs in previous studies. Importantly, increased expression of luciferase gene of pRLuc42R was observed by RT-PCR.ConclusionsThe present study offers an effective strategy to design a quick and sensitive biosensor for phenol by constructing recombinant bacteria having DmpR gene.

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“…K M is defined as the concentration of the specific substrate at which a given enzyme yields one-half its maximum velocity [19]. The values of R max remains the same irrespective of the present or absent of the inhibitor while the value of Michaelis-Menten constant (K M ) increases (Table 1) with increase in inhibitor concentration.…”

Section: Resultsmentioning

confidence: 99%

An Optical Test Strip for the Detection of Benzoic Acid in Food

Hamzah

Yusof

Salleh

et al. 2011

Sensors

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Fabrication of a test strip for detection of benzoic acid was successfully implemented by immobilizing tyrosinase, phenol and 3-methyl-2-benzothiazolinone hydrazone (MBTH) onto filter paper using polystyrene as polymeric support. The sensing scheme was based on the decreasing intensity of the maroon colour of the test strip when introduced into benzoic acid solution. The test strip was characterized using optical fiber reflectance and has maximum reflectance at 375 nm. It has shown a highly reproducible measurement of benzoic acid with a calculated RSD of 0.47% (n = 10). The detection was optimized at pH 7. A linear response of the biosensor was obtained in 100 to 700 ppm of benzoic acid with a detection limit (LOD) of 73.6 ppm. At 1:1 ratio of benzoic acid to interfering substances, the main interfering substance is boric acid. The kinetic analyses show that, the inhibition of benzoic is competitive inhibitor and the inhibition constant (Ki) is 52.9 ppm. The activity of immobilized tyrosinase, phenol, and MBTH in the test strip was fairly sustained during 20 days when stored at 3 °C. The developed test strip was used for detection of benzoic acid in food samples and was observed to have comparable results to the HPLC method, hence the developed test strip can be used as an alternative to HPLC in detecting benzoic acid in food products.

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Chitosan-based tyrosinase optical phenol biosensor employing hybrid nafion/sol–gel silicate for MBTH immobilization

Cited by 55 publications

References 25 publications

Self-assembled, photoluminescent peptide hydrogel as a versatile platform for enzyme-based optical biosensors

Self-assembled, photoluminescent peptide hydrogel as a versatile platform for enzyme-based optical biosensors

An Effective Strategy for a Whole-Cell Biosensor Based on Putative Effector Interaction Site of the Regulatory DmpR Protein

An Optical Test Strip for the Detection of Benzoic Acid in Food

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