MyMedR

Displaying all 5 publications

Abstract:

Sort:

The potential use of a layer-by-layer strategy to develop LDPE antimicrobial films coated with silver nanoparticles for packaging applications

Azlin-Hasim S, Cruz-Romero MC, Cummins E, Kerry JP, Morris MA

J Colloid Interface Sci, 2016 Jan 01;461:239-248.
PMID: 26402783 DOI: 10.1016/j.jcis.2015.09.021

Commercial low-density polyethylene (LDPE) films were UV/ozone treated and coated using a layer-by-layer (LbL) technique by alternating the deposition of polyethyleneimine (PEI) and poly(acrylic acid) (PAA) polymer solutions and antimicrobial silver (Ag). The effects of the initial pH of the PEI/PAA polymer solutions alternating layers (pH 10.5/4 or 9/6.5) on the antimicrobial activity of the developed LbL coatings combined with Ag against Gram-negative and Gram-positive bacteria were investigated. The results from fourier transform infrared spectroscopy and toluidine blue O assay showed that LDPE LbL coated using PEI/PAA polymer solutions with initial pH of 10.5/4 significantly increased the presence of carboxylic acid groups and after Ag attachment the coating had higher antimicrobial activity against both Gram-negative and Gram-positive bacteria compared to the LDPE LbL coated using PEI/PAA polymer solutions with initial pH of 9/6.5. The LDPE LbL coated films using non-modified pH PEI/PAA polymer solutions decreased the water contact-angle indicating an increased hydrophilicity of the film, also increased the tensile strength and roughness of LDPE LbL coated films compared to uncoated LbL samples. The LDPE LbL coated films attached with Ag(+) were UV/ozone treated for 20 min to oxidise Ag(+) to Ag(0). The presence of Ag(0) (Ag nanoparticles (NPs)) on the LDPE LbL coated films was confirmed by XRD, UV-vis spectrophotometer and colour changes. The overall results demonstrated that the LbL technique has the potential to be used as a coating method containing antimicrobial Ag NPs and that the manufactured films could potentially be applied as antimicrobial packaging.
Assessment of the migration potential of nanosilver from nanoparticle-coated low-density polyethylene food packaging into food simulants

Hannon JC, Kerry JP, Cruz-Romero M, Azlin-Hasim S, Morris M, Cummins E

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2016;33(1):167-78.
PMID: 26523861 DOI: 10.1080/19440049.2015.1114184

An experimental nanosilver-coated low-density polyethylene (LDPE) food packaging was incubated with food simulants using a conventional oven and tested for migration according to European Commission Regulation No. 10/2011. The commercial LDPE films were coated using a layer-by-layer (LbL) technique and three levels of silver (Ag) precursor concentration (0.5%, 2% and 5% silver nitrate (AgNO3), respectively) were used to attach antimicrobial Ag. The experimental migration study conditions (time, temperature and food simulant) under conventional oven heating (10 days at 60°C, 2 h at 70°C, 2 h at 60°C or 10 days at 70°C) were chosen to simulate the worst-case storage period of over 6 months. In addition, migration was quantified under microwave heating. The total Ag migrant levels in the food simulants were quantified by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Mean migration levels obtained by ICP-AES for oven heating were in the range 0.01-1.75 mg l(-1). Migration observed for microwave heating was found to be significantly higher when compared with oven heating for similar temperatures (100°C) and identical exposure times (2 min). In each of the packaging materials and food simulants tested, the presence of nanoparticles (NPs) was confirmed by scanning electron microscopy (SEM). On inspection of the migration observed under conventional oven heating, an important finding was the significant reduction in migration resulting from the increased Ag precursor concentration used to attach Ag on the LDPE LbL-coated films. This observation merits further investigation into the LbL coating process used, as it suggests potential for process modifications to reduce migration. In turn, any reduction in NP migration below regulatory limits could greatly support the antimicrobial silver nanoparticle (AgNP)-LDPE LbL-coated films being used as a food packaging material.
Human exposure assessment of silver and copper migrating from an antimicrobial nanocoated packaging material into an acidic food simulant

Hannon JC, Kerry JP, Cruz-Romero M, Azlin-Hasim S, Morris M, Cummins E

Food Chem Toxicol, 2016 Sep;95:128-36.
PMID: 27402098 DOI: 10.1016/j.fct.2016.07.004

To examine the human exposure to a novel silver and copper nanoparticle (AgNP and CuNP)/polystyrene-polyethylene oxide block copolymer (PS-b-PEO) food packaging coating, the migration of Ag and Cu into 3% acetic acid (3% HAc) food simulant was assessed at 60 °C for 10 days. Significantly lower migration was observed for Ag (0.46 mg/kg food) compared to Cu (0.82 mg/kg food) measured by inductively coupled plasma - atomic emission spectrometry (ICP-AES). In addition, no distinct population of AgNPs or CuNPs were observed in 3% HAc by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). The predicted human exposure to Ag and Cu was used to calculate a margin of exposure (MOE) for ionic species of Ag and Cu, which indicated the safe use of the food packaging in a hypothetical scenario (e.g. as fruit juice packaging). While migration exceeded regulatory limits, the calculated MOE suggests current migration limits may be conservative for specific nano-packaging applications.
Can the complete blood count be used as a reliable screening tool for obstructive sleep apnea?

Cummins E, Waseem R, Piyasena D, Wang CY, Suen C, Ryan C, et al.

Sleep Breath, 2021 Jun 29.
PMID: 34185230 DOI: 10.1007/s11325-021-02383-3

PURPOSE: Since hypoxia increases erythropoietin production and inflammation, the complete blood count (CBC) has been proposed as an inexpensive alternative for obstructive sleep apnea (OSA) screening. The objective of this study was to determine whether or not intermittent hypoxia and OSA severity, as measured by the mean oxygen saturation (SpO2) and apnea-hypopnea index (AHI), affect parameters measured by the CBC.
METHODS: This retrospective study included a total of 941 surgical patients who had a pre-operative home sleep study. The pre-operative CBC was extracted from the electronic patient records. Patients were stratified according to their AHI scores, into mild (AHI ≥ 5 -
Spray coating application for the development of nanocoated antimicrobial low-density polyethylene films to increase the shelf life of chicken breast fillets

Azlin-Hasim S, Cruz-Romero MC, Morris MA, Cummins E, Kerry JP

Food Sci Technol Int, 2018 Dec;24(8):688-698.
PMID: 30044138 DOI: 10.1177/1082013218789224

Antimicrobial coated films were produced by an innovative method that allowed surface modification of commercial low-density polyethylene films so that well-defined antimicrobial surfaces could be prepared. A Pluronic™ surfactant and a polystyrene-polyethylene oxide block copolymer were employed to develop modified materials. The Pluronic™ surfactant provided a more readily functionalised film surface, while block copolymer provided a reactive interface which was important in providing a route to silver nanoparticles that were well adhered to the surface. Antimicrobial films containing silver were manufactured using a spray coater and the amount of silver used for coating purposes varied by the concentration of the silver precursor (silver nitrate) or the number of silver coatings applied. Potential antimicrobial activity of manufactured silver-coated low-density polyethylene films was tested against Pseudomonas fluorescens, Staphylococcus aureus and microflora isolated from raw chicken. The microbiological and physicochemical quality of chicken breast fillets wrapped with silver-coated low-density polyethylene films followed by vacuum skin packaging was also assessed during storage. Antimicrobial activity of developed silver-coated low-density polyethylene films was dependent ( p