Nanosized Fe3O4 an efficient PCR yield enhancer-Comparative study with Au, Ag nanoparticles

Nanomaterials-assisted PCR is a promising field of nanobiotechnology that amalgamates nanomaterials into the conventional PCR system to achieve better amplification of desired product. With literature documenting the variable effects of these nanomaterials on the PCR yield and amplification; it was thought worthwhile to compare the PCR enhancing efficiency of three transition metal nanoparticles in form of stable colloidal suspensions at varying concentrations.The nanoparticles(NPs) of silver, gold and magnetite were chemically synthesized by reducing their respective salts and characterized using UV-vis spectroscopy. Their morphology was assessed using nanoparticle tracking system and AFM. The effect of these nanofluids on amplification of 800 bp prokaryotic DNA template with 30% GC content was studied using conventional thermal cycler. The reaction kinetics for all the three nanofluids yielded a Gaussian curve of amplification with varying concentrations. The ammonium salt of oleic acid coated magnetite (Fe3O4) nanoparticles at a concentration of 0.72 × 10(-2)nM and average size of 33 nm demonstrated highest amplification efficiency of 190% as compared to the citrate stabilized AgNP-25 nm (45%) and AuNP-15.19 nm (134%) using a conventional PCR system. The major reasons that allow Fe3O4 NPs outperform the other 2 transition metal NP's seem to be attributed to its heat conduction property as well as effective adsorption of PCR components onto the ammonium salt of oleic acid coated magnetite nanofluids. The data from our study offers valuable information for the application of ferrofluids as economically, efficient and effective alternative for nanomaterial-assisted PCR yield enhancers.

Attenuation of lysozyme amyloid cytotoxicity by SPION-mediated modulation of amyloid aggregation

The formation and deposition of proteinaceous aggregates of amyloid fibrils characterize diverse degenerative diseases, such as Alzheimer's, Parkinson's, and systemic amyloidosis. The presence of these aggregates is associated with clinical manifestations, and various forms of amyloid aggregates have been identified to be cytotoxic. Although the exact mechanism of amyloid toxicity remains to be elucidated, prevention of amyloid fibril formation and aggregation forms a possible therapeutic approach. Nanomaterials possess the potential for such a strategy. Using hen egg white lysozyme (HEWL) as a prototypic amyloid-forming protein, we found a reduction in the aggregation rate of HEWL in the presence of super-paramagnetic iron oxide nanoparticles (SPIONs) with slowing of nucleation and amyloid fibril elongation. HEWL-amyloid had a predominantly fibrillar structure and was toxic to various cells. A significant attenuation of cytotoxicity was observed when cells were treated with SPION-interacted HEWL-amyloid. Ultra-structural differences were observed between the native and SPION-interacted HEWL-amyloids by SEM and TEM imaging. Our findings confirm that SPIONs perturb amyloid fibrillation, thereby reducing the cytotoxicity of amyloid.

Studies on degradation efficiency of polycaprolactone by a naturally-occurring bacterium

We report a strain of Bacillus, isolated from the rhizosphere of the mangrove Sesuvium portulacastrum, that degrades polycaprolactone (PCL) on timescales that are a factor of three shorter than hitherto reported, with complete degradation in only 20 days. The bacterium has been identified as Bacillus pumilus by means of 16S rRNA gene sequencing and FAME analysis; it secretes proteases and lipases and its 'de-polymerase' activity is evident by the zone of clearing in emulsified PCL. It is an aerobic chemoheterotroph capable of utilizing a variety of carbohydrates. Although not a true psychrophile, is a mesophile, growing optimally over a temperature range 30-45 degrees C and pH range 5-12.5. It is a halophile tolerating NaCI concentrations up to 10% w/v, and is unique in degrading and utilizing PCL and its monomer, epsilon-caprolactone (CL), as a sole carbon source. Degradation of PCL was monitored using Fourier Transform Infrared (FTIR) spectroscopy, light microscopy and scanning electron microscopy (SEM). This degradation was found to be enhanced by salts (NaCl, KCI, MgSO4, Na2HPO4) and at medium pH values in excess of 7. Under the same growth conditions, another standard Bacillus pumilus strain showed somewhat reduced PCL-degradation.