Nanobio and BioNano

Catalytically active nanomaterials: A promising candidate for artificial enzymes

2021-05-17T16:44:18+00:00

Enzymes are highly efficient biomolecules that speed upÂ biochemical reactions. They usually exhibit high specificity to theirÂ distinctive substrates with enzymatic activities normally takingÂ place in mild conditions [1]. Enzymes provide significant numberÂ of assistance from mediating cellular metabolisms to theÂ utilization in industrial processes such as pharmaceutical, food andÂ agrochemical industries.Â However, â€˜natural limitationsâ€™ hinder the usage ofÂ enzymes to its maximum trajectory e.g. harsh environmental conditionÂ that affects catalytic capability (i.e. by protein denaturation or enzyme being digested). In addition, there are many difficulties that affect enzyme recovery and industrial operation often requiresÂ exorbitantÂ cost of preparation for purification [1]. While the advancement in biotechnology leads to the exploration of biomolecules with enzymatic properties including cyclodextrins, metal complexes, porphyrins, polymers, and dendrimers, nanobiotechnology explores nanomaterials. There are varieties of nanomaterials that have been extensively explored to mimic the structures and functions of naturally occurring enzymes, namely; gold nanoparticles, platinum nanomaterials, nanoceria, iron and copper oxides, manganese dioxide and others. These nanomaterials (with artificial enzyme mimicking activities) were successfully utilized in immunoassays, cancer diagnostics and therapies, neuroprotection, stem cell growth, pollutant removal and biosensing applications [1].

Functional gold-nanoparticles based colorimetric assay for medical and industrial use

2021-05-17T16:46:55+00:00

Nanosize materials have been widely available in various research fields as an advanced technology. Gold nanoparticles (GNPs) have unique optical, electrical, and magnetic properties. Especially, the optical spectrum of GNPs shows a localized surface plasmon band in the region of 520â€“550 nm. Te wavelength of spectrum of GNPs change drastically longer when several particles come close to each other. Various types of GNP based assays that was conjugated with functional biomolecules have been developed to take advantage of the optical property. Tis review introduces the optical assays using GNPs conjugated with biomolecules for medical and industrial use.

A rapid inhibitive assay for the determination of heavy metals using Î±-chymotrypsin; a serine protease

2021-05-17T16:47:53+00:00

Agricultural areas in Malaysia depend upon unpolluted source of water and hence needÂ continuous monitoring. An enzyme-based assay for the detection of xenobiotics is a promisingÂ low cost and rapid method for monitoring. An enzymatic-heavy metal assay has been developedÂ using Î±-chymotrypsin; a serine protease. This enzyme is assayed by using casein as a substrateÂ with Coomassie dye to track the complete hydrolysis of casein. In the absence of inhibitors, caseinÂ is hydrolysed to completion and the solution is brown. Eight heavy metals were tested on the Î±-Â chymotrypsin bioassays and in the presence of Hg2+, Cr2+ and Zn2+ at the final concentration ofÂ 5mg/L, hydrolysis of casein is inhibited and the solution remains blue. The assay was sensitive to
Hg2+, Cr2+ and Zn2+ with an IC50 (the concentration of toxicant giving 50% inhibition) of 1.34Â mg/L, 1.974 mg/L and 2.49 mg/L, respectively. The calculated limits of quantitation (LOQ) valueÂ for Hg2+, Cr2+ and Zn2+ were 0.012 mg/L, 0.324 mg/L and 0.098 mg/L, respectively. TheÂ calculated LOD values for Hg2+, Cr2+ and Zn2+ were 0.003 mg/L, 0.320 mg/L and 0.074 mg/L,Â respectively. The results of this study indicate that this assay has the potential to be used as a toolÂ in biosensor development for the determination of heavy metals in various samples.

Morphological structure of Kappaphycus alvarezii under scanning electron microscope after degradation in acidic solution

2021-05-17T16:48:33+00:00

Seaweeds are an increasingly popular macroalgae with intensive cultivation being carriedÂ carried out in East Malaysia especially from the species Kappaphycus alvarezii and GracilariaÂ salicornia. Tese species have unique saccharides that warrant further exploration. K. alvarezii isÂ rich in carrageenan and sulphated sugars. Other important polysaccharides are agars, xylans,
floridean starch and water-soluble sulphated galactan which can be used in manyÂ biotechnology applications. Despite this only a few studies have been carried out to understandÂ their hydrolysis behavior into the nanosize level morphological structure using ScanningÂ Electron Microscope (SEM). Seeaweeds are also rich in oxygen believed to be in the form ofÂ hydroxyl bond making them harder to be broken down. Generally, chemical method is used toÂ hydrolyse seaweed polysaccharides into their respected monosaccharides. Tis study shows thatÂ the morphologies of K. alverazii exhibits smooth surface with salt crystalloid deposition covering the area. Te study samples also show some reticulated and blocky image. Te shrink fibrilsÂ could be seen clearly due to the dried sample used before treatment. Te fractured surface afterÂ heating treatment at high temperature shows a removal of surface impurities. Te treatmentÂ also resulted in the leaching out of the salt crystalloid deposition layer and more internalÂ structure was exposed. Another observation revealed the existence of pores on the surface.Â Finally the surfaces of K. alverazii contain less microstructures and the microfibrils structureÂ become broken as the broken microfibers can be clearly seen on the fiber surfaces. Tis mayÂ benefit to increase total surface area for further hydrolysis process.

Modelling the growth kinetics of E. coli measured using real-time impedimetric biosensor

2021-05-17T16:49:15+00:00

The development of in situ sensor for measuring bacterial concentrations in fermenter wouldÂ allow real-time monitoring of the concentration of bacteria. Kim et al [1] has developed such aÂ method using impedance spectroscopy, and was able to measure in real-time the concentration ofÂ E. coli at 0.01 MHz frequency using impedance changes. In this work we used severalÂ mathematical models of bacterial growth kinetics such as logistic, Gompertz, Richards, Schnute,Â Baranyi-Roberts, Von Bertalanffy, Buchanan three-phase and the Huang models to model theÂ resulting bacterial growth curve from Kim et al. The Buchanan three-phase model was chosen asÂ the best model based on statistical tests such as root-mean-square error (RMSE), adjustedÂ coefficient of determination (R2), bias factor (BF), accuracy factor (AF) and corrected AICc
(Akaike Information Criterion). Parameters obtained from the growth fitting exercise wereÂ maximum specific growth rate (Î¼max), lag time (Î») and maximal number of cells achieved perÂ droplet (Ymax) with values of 0.67Â±0.086 (h-1), 2.45Â±0.24 (h) and 20.26Â±0.038 (ln cell no/ml),Â respectively. The parameters obtained from fitting the bacterial growth curve using this model canÂ be used for further modeling and optimization exercises for identifying key optimal parametersÂ for improving the sensitivity of the biosensor.

Statistical diagnostic tests of residuals from the Gompertz model used in the fitting of the growth of E. coli measured using a real-time impedimetric biosensor

2021-05-17T16:49:43+00:00

The development of in situ sensor for measuring bacterial concentrations in biotechnology andÂ the health sciences would allow real-time monitoring of the concentration of bacteria. Kim et alÂ [1] has developed such a method using impedance spectroscopy, and was able to measure in realtimeÂ the concentration of E. coli at 0.01 MHz frequency using impedance changes. We modeledÂ the growth kinetics using several nonlinear regression methods and discovered that the modifiedÂ Gompertz model is the best model for the growth of the bacterium [2]. It is well known thatÂ nonlinear regression of a data and further statistical analysis to find the best model relies on theÂ facts that the residuals (difference between observed and predicted data) followed a normal orÂ Gaussian distribution and that the data must be free of outliers. If all of these assumptions areÂ satisfied, the test is said to be robust. In this work we perform statistical diagnostics to theÂ residuals to satisfy the requirements above and found that removal of an outlier allows theÂ residuals to conform to all of the requirements above. The results indicated that remodelling of theÂ Gompertz model using the new set of data should be carried out.