Synthesis and characterisation of iron oxide nanoparticles conjugated with epidermal growth factor receptor (EGFR) monoclonal antibody as MRI contrast agent for cancer detection

The aim of this study is to synthesise superparamagnetic iron oxide nanoparticles conjugated with anti-epidermal growth factor receptor monoclonal antibody (ANTI-EGFR-SPION) and investigate its physicochemical characterisation and biocompatibility as a targeted magnetic resonance imaging (MRI) contrast agent for the EGFR-specific detection in EGFR expressing tumour cells. These particles employed biocompatible polymers, poly(D,L-lactide-co-glycolide) (PLGA) and polyethylene glycol aldehyde (PEG-aldehyde), to increase the half-life of particles in circulation and reduce their side effects. The Fe₃O₄-loaded PLGA-PEG-aldehyde nanoparticles were prepared by a modified water-in-oil-in-water double emulsion method. The EGFR antibody was conjugated to the surface of SPIONs using the aldehyde-amine reaction. Synthesised conjugates (nanoprobes) were characterised using Fourier transform infrared spectrophotometry, dynamic light scattering, transmission electron microscopy images, and vibrating-sample magnetometery, and the results showed that the conjugation was successful. The mean diameter of nanoprobes was about 25 nm. These nanoprobes exhibited excellent water-solubility, stability, and biocompatibility. Meanwhile, MR susceptibility test proved that synthesised nanoprobes can be managed for negative contrast enhancement. The results of this study suggested the potential use of these nanoprobes for non-invasive molecular MRI in EGFR detection in the future.

Eco-friendly synthesis of silver and gold nanoparticles with enhanced antimicrobial, antioxidant, and catalytic activities

The present work is emphasised on the bio-fabrication of silver and gold nanoparticles in a single step by a microwave-assisted method using the leaf extract of Synedrella nodiflora as both reducing and stabilising agent. The synthesised nanoparticles are highly stable and show surface plasmon resonance peak at 413 and 535 nm, respectively, for silver and gold nanoparticles in UV-Vis spectrum. The functional group responsible for the reduction of metal ions were obtained from Fourier transform infrared spectroscopy. The crystalline nature of nanoparticles with face-centred cubic geometry was confirmed by the X-ray diffraction and selected area electron diffraction patterns. The morphology and sizes of the silver and gold nanoparticles were obtained from transmission electron microscopy images. The nanoparticles exhibit effective antimicrobial activities against various pathogenic strains. These antimicrobial properties were analysed by employing agar well diffusion method. The nanoparticles show significant antioxidant properties, and it was determined using 2, 2-diphenyl-1-picrylhydrazyl assay. The nanoparticles also show potent catalytic activity in the degradation of anthropogenic pollutant dyes Congo red and eosin Y by excess NaBH4. Thus, the current study demonstrates the potential use of S. nodiflora as a reducing and stabilising agent for the synthesis of silver and gold nanoparticles and their relevance in the field of biomedicine and catalysis.

Magnetic soy protein isolate-bovine serum albumin nanoparticles preparation as a carrier for inulinase immobilisation

Magnetic nanoparticles (NPs) were functionalised with soy protein isolate (SPI) and bovine serum albumin (BSA) for inulinase immobilisation. The results revealed the nanomagnetite size of about 50 nm with a polydispersity index (PDI) of 0.242. The average size of the SPI NPs prepared by using acetone was 80-90 nm (PDI, 0.277), and SPI-BSA NPs was 80-90 nm (PDI, 0.233), and their zeta potential was around -34 mV. The mean diameter of fabricated Fe3O4@SPI-BSA NPs was <120 nm (PDI, 0.187). Inulinase was covalently immobilised successfully through glutaraldehyde on Fe3O4@SPI-BSA NPs with 80% enzyme loading. Fourier transform infrared spectra, field emission scanning electron microscopy, and transmission electron microscopy images provided sufficient proof for enzyme immobilisation on the NPs. The immobilised inulinase showed maximal activity at 45°C, which was 5°C higher than the optimum temperature of the free enzyme. Also, the optimum pH of the immobilised enzyme was shifted from 6 to 5.5. Thermal stability of the enzyme was considerably increased to about 43% at 75°C, and Km value was reduced to 25.4% after immobilisation. The half-life of the enzyme increased about 5.13-fold at 75°C as compared with the free form. Immobilised inulinase retained over 80% of its activity after ten cycles.