As Acrylamide Research Articles

Tannin impregnation pre-treatment of potatoes as a valuable strategy for acrylamide, monochloropropanediol and glycidol mitigation in chips and frying oil

This study focused on evaluating the mitigating effect of five different natural extracts of commercial tannins on the concentration of food contaminants such as acrylamide (AA), glycidols (GD), and monochloropropanediols (MCPDs) in potato chips and frying oils after the impregnation of potatoes with tannins. The impregnated samples were used to perform 4 consecutive fryings to simulate the effect produced in restaurants. AA mitigation was achieved in all pre-treated chips throughout the four frying cycles (except for the chestnut extract). The highest AA mitigation (86.6%) was achieved using quebracho extract. This correlated positively with the progress of Maillard reaction measured at 284 nm. In potato chips, 3-MCPD and GD were decreased by most tannins tested, whereas 2-MCPD was only mitigated using hydrolyzable tannins. However, in frying oils, 3-MCPD showed a decrease using chestnut, grape seed and quebracho extracts, 2-MCPD decreased using all tannins, and no effect was observed on GD. To our knowledge, this is the first study using tannins as a mitigation strategy to decrease MCPDs and GD; and it seems a good approach to keep low concentrations of these compounds. Indeed, hydrolyzable tannins seem the best option to mitigate MCPD and GD and condensed tannins the best one to mitigate AA.

Food process contaminants: formation, occurrence, risk assessment and mitigation strategies - a review.

Thermal treatment of food can lead to the formation of potentially harmful chemicals, known as process contaminants. These are adventitious contaminants that are formed in food during processing and preparation. Various food processing techniques, such as heating, drying, grilling, and fermentation, can generate hazardous chemicals such as acrylamide (AA), advanced glycation end products (AGEs), heterocyclic aromatic amines (HAAs), furan, polycyclic aromatic hydrocarbons (PAHs), N-nitroso compounds (NOCs), monochloropropane diols (MCPD) and their esters (MCPDE) which can be detrimental to human health. Despite efforts to prevent the formation of these compounds during processing, eliminating them is often challenging due to their unknown formation mechanisms. It is critical to identify the potential harm to human health in processed food and understand the mechanisms by which harmful compounds form during processing, as prolonged exposure to these toxic compounds can lead to health problems. Various mitigation strategies, such as the use of diverse pre- and post-processing treatments, product reformulation, additives, variable process conditions, and novel integrated processing techniques, have been proposed to control these food hazards. In this review, we summarize the formation and occurrence, the potential for harm to human health produced by process contaminants in food, and potential mitigation strategies to minimize their impact.

The role of microRNAs in acrylamide toxicity.

The chemical compound known as Acrylamide (AA) is employed in different industries worldwide and is also found in thermal-processed food. AA has been acting as a reproductive toxicant, carcinogen, and neurotoxic in various animals, which may promote several toxic impacts in animal and human species. Up to now, various studies have focused on the harmful mechanisms and intervention actions of AA. However, the underlying mechanisms that AA and its toxic effects can exert have remained uncertain. MicroRNAs (miRNAs) are a class of short, non-coding RNAs that are able to act as epigenetic regulators. These molecules can regulate a wide range of cellular and molecular processes. In this regard, it has been shown that different chemical agents can dysregulate miRNAs. To determine the possible AA targets along with mechanisms of its toxicity, it is helpful to study the alteration in the profiles of miRNA regulation following AA intake. The current research aimed to evaluate the miRNAs' mediatory roles upon the AA's toxic potentials. This review study discussed the AA, which is made within the food matrix, the way it is consumed, and the potential impacts of AA on miRNAs and its association with different cancer types and degenerative diseases. The findings of this review paper indicated that AA might be capable of altering miRNA signatures in different tissues and exerting its carcinogen effects.

Effect of Acrylamide and Mycotoxins in SH-SY5Y Cells: A Review.

Thermal processes induce the formation of undesired toxic components, such as acrylamide (AA), which has been shown to induce brain toxicity in humans and classified as Group 2A by the International Agency of Research in Cancer (IARC), as well as some mycotoxins. AA and mycotoxins' toxicity is studied in several in vitro models, including the neuroblastoma cell line model SH-SY5Y cells. Both AA and mycotoxins occur together in the same food matrix cereal base (bread, pasta, potatoes, coffee roasting, etc.). Therefore, the goal of this review is to deepen the knowledge about the neurological effects that AA and mycotoxins can induce on the in vitro model SH-SY5Y and its mechanism of action (MoA) focusing on the experimental assays reported in publications of the last 10 years. The analysis of the latest publications shows that most of them are focused on cytotoxicity, apoptosis, and alteration in protein expression, while others are interested in oxidative stress, axonopathy, and the disruption of neurite outgrowth. While both AA and mycotoxins have been studied in SH-SY5Y cells separately, the mixture of them is starting to draw the interest of the scientific community. This highlights a new and interesting field to explore due to the findings reported in several publications that can be compared and the implications in human health that both could cause. In relation to the assays used, the most employed were the MTT, axonopathy, and qPCR assays. The concentration dose range studied was 0.1-10 mM for AA and 2 fM to 200 µM depending on the toxicity and time of exposure for mycotoxins. A healthy and varied diet allows the incorporation of a large family of bioactive compounds that can mitigate the toxic effects associated with contaminants present in food. Although this has been reported in some publications for mycotoxins, there is still a big gap for AA which evidences that more investigations are needed to better explore the risks for human health when exposed to AA and mycotoxins.

Application of cellulose- and chitosan-based edible coatings for quality and safety of deep-fried foods.

Excessive oil uptake and formation of carcinogens, such as acrylamide (AA), heterocyclic amines (HCAs), and polycyclic aromatic hydrocarbons (PAHs), during deep-frying are a potential threat for food quality and safety. Cellulose- and chitosan-based edible coatings have been widely applied to deep-fried foods for reduction of oil uptake because of their barrier property to limit oil ingress, and their apparent inhibition of AA formation. Cellulose- and chitosan-based edible coatings have low negative impacts on sensory attributes of fried foods and are low cost, nontoxic, and nonallergenic. They also show great potential for reducing HCAs and PAHs in fried foods. The incorporation of nanoparticles improves mechanical and barrier properties of cellulose and chitosan coatings, which may also contribute to reducing carcinogens derived from deep-frying. Considering the potential for positive health outcomes, cellulose- and chitosan-based edible coatings could be a valuable method for the food industry to improve the quality and safety of deep-fried foods.

Health risk assessment of process-related contaminants in bread.

Bread constitutes a popular and even daily component of human diet world-wide, Iran included. However, there are concerns that various processing methods such as frying and baking could result in the production of potentially a source of known carcinogens such as acrylamide (AA) and benzo(a)pyrene (BaP). The present study tried to perform a risk assessment on seven categories of bread consumers, based on age and gender, calculating the Target Hazard Quotient (THQ), Incremental Lifetime Cancer Risk (ILCR), and Margin of Exposure (MOE) related to the dietary intake of AA and BaP. AA and BaP were analyzed in 87 bread samples using LC-MS/MS and GC-MS/MS, respectively. The results indicated that more than 94% (mean concentration: 25.9ng/g) and about 20% (mean concentration: 1.98ng/g) of the samples were contaminated with AA and BaP, respectively. The THQ of AA intake through bread consumption for seven categories was in the following decreasing order: semi-industrial Sangak bread of Shiraz (SIS-Sh)> traditional Sangak bread of Shiraz (TS-Sh)> traditional Sangak bread of Tehran (TS-Th)> commercial bread of Tehran (C-Th). The non-neoplastic and neoplastic MOE for AA (˂10,000) indicates a high risk of exposure for all people in Tehran and Shiraz through the consumption of all tested bread. Due to the consumption of TS, SIS, and C bread, the BaP MOE for all people in Tehran and Shiraz was >10000, which shows a low health risk for consumers. Our findings showed that ILCR for AA in seven classes of people who had TS-Sh and TS-Th was remarkably higher than ILCR for all categories that consumed the C-Th. BaP ILCR for the people who ingested TS-Th, TS-Sh, SIS-Th, and SIS-Sh was about 2-4 times higher than people who had C-Th. This study indicates that bread is the main source of AA and BaP intake in Iran, which might elevate the cancer risk.

A Kinetic Model of Acrylamide Formation inside of the Heat Boundary Layer

The Maillard reaction is important for the formation of color and aroma in heat-processed foods, but it may also be associated with the formation of toxic compounds, such as acrylamide (AA) and hydroxymethylfurfural (HMF). In an acetic acid food system, the major characteristics of the heating process are heat transfer and mass transfer. During high-temperature heating, an acetic acid system contains a heat boundary layer (HBL). For the food system, AA and HMF formations are complex on the inside of the HBL. To assess the effects of chitosan addition on the inhibition of AA formation, a kinetic model in the food system was developed that combined the Langmuir adsorption mechanism, the coverage function, the relative efficiency of chitosan dispersion, and the step function to predict the entire heating time. The inhibition of AA formation in asparagine-glucose-chitosan solution is dependent on chitosan addition and chitosan dispersion on the inside of the HBL. For extending heating duration, AA forms with high loading of glucose and asparagine were significantly higher than those with low loading. The effect of the asparagine on the AA content is related to one reaction pathway in the AA formation. However, the effect of sugar reduction on the AA content is due to two reaction pathways. For heating circumstances, a process prediction with different glucose and asparagine loadings was developed. • A heat process prediction with different Glu and Asp loadings was developed. • Model formed from Langmuir adsorption, coverage function and chitosan dispersion. • AA forms in Asp-Glu-chitosan system dependent on chitosan added and dispersed in HBL. • Influence of asp is due to a single reaction pathway in the formation of AA. • Influence of reducing sugar is on two reaction pathways in the formation of AA.

Synergic effect of phytase, amylase, galactosidase, and asparaginase activity on the mitigation of acrylamide and hydroxymethylfurfural in roll bread by co-culture fermentation

In this study, the effect of co-culture Lactobacillus acidophilus ATCC 4356 and Lactobaacillus. plantarum ATCC 20552 on enzyme production (phytase, α-amylase, α-galactosidase and asparaginase (ASNase)), as well as acrylamide (AA) and 5-Hydroxymethylfurfural (HMF) levels in fermented bread, were determined. Based on the findings herein, the maximum levels of phytase (112.8–163 (U/mL), α-amylase (84.9–180.6 U/mL), α-galactosidase (2.33–6.72 U/mL), and asparaginase (5.23–9.14 U/mL) were calculated after 8 h of co-culture fermentation. The phytase and asparaginase activity of L. plantarum was higher than that of L. acidophilus while L. acidophilus showed higher α-amylase and α-galactosidase activity compared to L. plantarum. The phytic acid session caused an increase in the mineral content, thereby synergically affecting the rise in the amylase and asparaginase activity. The results also showed that acrylamide and HMF levels in breads fermented using co-culture L. acidophilus and L. plantarum + yeast was much lower (185.7 ± 1.1–34.6 ± 0.3 μg/kg d.b. and 12.3 ± 1.1 – <0.5 mg/kg d.b.) compared with those in the yeast-only fermented bread (334.9 ± 0.8–208.1 ± 0.7 μg/kg d. b. and 33.6 ± 1.2–20.5 ± 0.7 mg/kg d.b.), respectively. According to the treatment results, co-culture fermentation as along with time and temperature of proofing could be considered as potential factors to reduce AA and HMF content.

3D printing nanocomposite hydrogels with lattice vascular networks using stereolithography

Hydrogels have emerged as leading candidates to reproduce native extracellular matrix. To provide structures and functions similar to tissues in vivo, controlled porosity and vascular networks are required. However, fabrication techniques to introduce these are still limited. In this study we propose stereolithography as a fabrication technique to achieve 3D vascular networks using water-based solvents only. A 3D printable hydrogel is formulated based on available commercial chemicals such as acrylamide (AAm) and polyethylene glycol diacrylate 700 (PEGDA700), with nanocellulose crystals (CNC) as a nanofiller. An optimisation procedure to increase resolution, tune porosity as well as mechanical properties is developed. The results highlight the importance of photoabsorber addition to improve channel resolution. We demonstrate that with the adequate choice of chemicals and fillers for photocurable formulations, structural and functional properties of the fabricated scaffold can be tailored, opening the path for advanced applications.Graphic abstract

Single-Step Synthesis of Alginate Microgels Enveloped with a Covalent Polymeric Shell: A Simple Way to Protect Encapsulated Cells.

Microgels of biopolymers such as alginate are widely used to encapsulate cells and other biological payloads. Alginate is an attractive material for cell encapsulation because it is nontoxic and convenient: spherical alginate gels are easily created by contacting aqueous droplets of sodium alginate with divalent cations such as Ca2+. Alginate chains in the gel become cross-linked by Ca2+ cations into a 3-D network. When alginate gels are placed in a buffer, however, the Ca2+ cross-links are eliminated by exchange with Na+, thereby weakening and degrading the gels. With time, encapsulated cells are released into the external solution. Here, we describe a simple solution to the above problem, which involves forming alginate gels enveloped by a thin shell of a covalently cross-linked gel. The shell is formed via free-radical polymerization using conventional monomers such as acrylamide (AAm) or acrylate derivatives, including polyethylene glycol diacrylate (PEGDA). The entire process is performed in a single step at room temperature (or 37 °C) under mild, aqueous conditions. It involves combining the alginate solution with a radical initiator, which is then introduced as droplets into a reservoir containing Ca2+ and monomers. Within minutes of either simple incubation or exposure to ultraviolet (UV) light, the droplets are converted into alginate-polymer microcapsules with a core of alginate and a shell of the polymer (AAm or PEGDA). The microcapsules are mechanically more robust than conventional alginate/Ca2+ microgels, and while the latter swell and degrade when placed in buffers or in chelators like sodium citrate, the former remain stable under all conditions. We encapsulate both bacteria and mammalian cells in these microcapsules and find that the cells remain viable and functional over time. Lastly, a variation of the synthesis technique is shown to generate multilayered microcapsules with a liquid core surrounded by concentric layers of alginate and AAm gels. We anticipate that the approaches presented here will find application in a variety of areas including cell therapies, artificial cells, drug delivery, and tissue engineering.

Effects of metal ions on formation of acrylamide and 5‐hydroxymethylfurfural in asparagine–glucose model system

SummaryUndesirable substances of thermal food processing such as acrylamide (AA) and 5‐hydroxymethylfurfural (HMF) have been intensively studied in recent decades. The aim of this work was to investigate the evolution mechanism of AA and HMF contents in the presence of various valence metal cations at various concentrations in asparagine–glucose model system. Three interesting phenomena were found. Firstly, the AA contents first decreased and then increased, whereas the HMF contents first increased and then decreased, with increasing metal cations concentration; secondly, the concentration of cations for maximal HMF contents was lower than the concentration of cations for minimal AA contents; thirdly, the maximum AA‐inhibiting or HMF‐promoting efficiency was achieved more readily with trivalent, then divalent and lastly monovalent cations. These phenomena can be explained by that increasing the metal cations concentration can increase the protonated product contents, thus increasing the AA‐inhibiting efficiency and HMF‐promoting efficiency. With higher metal cations concentration in the model system, HMF as a reactant can react with the asparagine to form AA or directly decompose into furfural. These interesting results can provide a theoretical foundation to simultaneously control the formation of AA and HMF during food processing.

Collagen-based hydrogel films as drug-delivery devices with antimicrobial properties

Collagen (coll)-containing hydrogel films were prepared by mixing degraded collagen with monomers such as acrylamide (AAm), and 2-hydroxy ethylmethacrylate (HEMA) before the polymerization/cross-linking of composites as p(coll-co-AAm), and p(coll-co-HEMA), respectively. These materials were used as drug-delivery devices for potential wound dressing materials by loading and releasing of model drugs such as gallic acid (GA) and naproxen (NP). A linear release profile was obtained up to 32-h release from GA-loaded p(coll-co-AAm) interpenetrating polymeric networks films, and 36-h linear release profile of NP for p(coll-co-HEMA). Furthermore, metal nanoparticles such as Ag and Cu prepared within these hydrogel films offered antimicrobial characteristic against known common bacteria such as Escherichia coli, Bacillus subtilis, and Staphylococcus aureus.

Investigation of variations in the acrylamide and N(ε) -(carboxymethyl) lysine contents in cookies during baking.

Baking processing is indispensable to determine special sensory prosperities of cookies and induces the formation of some beneficial components such as antioxidants. However, the formation of some Maillard reaction-derived chemical hazards, such as acrylamide (AA) and N(ε) -(carboxymethyl) lysine (CML) in cookies is also a significant consequence of baking processing from a food safety standpoint. This study investigated the effects of baking conditions on the formation of AA and CML, as well as the antioxidant activity (AOA) of cookies. Cookies were baked at various baking temperatures (155 to 230 °C) and times (1.5 to 31 min). AA and CML contents were determined by ultra-performance liquid chromatography-tandem mass spectrometry, respectively. The highest level of AA was obtained in the cookies baked at 155 °C/21 min and 205 °C/11 min (328.93 ± 3.10 μg/kg and 329.29 ± 5.29 μg/kg), while the highest level of CML was obtained in the cookies baked at 230 °C/1.5 min (118.05 ± 0.21 mg/kg). AA was prone to form at relatively low temperature range (155 to 205 °C), however, CML at relatively high temperature range (205 to 230 °C). The CML content was much higher than the AA content in the same set of cookies, by about 2 to 3 orders of magnitude. The AOA of cookies increased at more severe baking conditions. According to the AA and CML content, AOA and sensory properties of cookies, the temperature-time regime of 180 °C/16 min might be a compromised selection. However, only optimizing the baking condition was not enough for manufacture of high-quality cookies. Cookies, a kind of widely consumed bakery products in the world, contain some potentially harmful compounds, like acrylamide (AA) and N(ε) -(carboxymethyl) lysine (CML). AA in cookies has led to public health concern and several research efforts. But CML, another Maillard reaction-derived chemical hazard, has been neglected so far, even though its content is much higher than that of AA in cookies. The results contribute to further insight into the Maillard reaction and are useful for the selection of baking conditions to produce high-quality cookies with lower AA and CML contents, higher AOA, and better sensory properties.

Abstract 4692: Comparison of dietary exposure to acrylamide and acrolein: monitoring mercapturic acids in human urine after consumption of potato crisps

Abstract Acrolein (AC) is an α,ß-unsaturated aldehyde, classified by the IARC in group 3B (not classifiable as to its carcinogenicity to humans). It is supposed to be formed by heating of fat containing foods, via heat induced formation from glycerides/glycerol. Formation of AC from carbohydrates has also been discussed [Stevens and Maier, 2008]. Moreover, it also has been suggested that AC might be formed by endogenous metabolism as a side product of carbohydrate and/or amino acid turnover or by oxidative desamination of polyamines. Analytical determination of AC in foodstuffs is difficult, due to its high volatility and reactivity. Data on exposure and contents of AC in heat treated foods therefore are scarce. It is unclear, to which extent AC contributes to the overall exposure of heat induced biologically active compounds such as acrylamide (AA) and furan. AC forms 1,4-Michael type adducts of biomolecular targets with nucleophiles like sulfhydryl and amino groups. In the organism, AC is mainly conjugated to glutathione and excreted after degradation and reduction as the mercapturic acid (MA), N-acetyl-S-(3-hydroxypropyl)-cysteine (3-HPMA). In the present study, AC exposure and detoxification kinetics were investigated within the scope of a human study with 13 healthy volunteers ingesting a test meal of 150 g potato crisps. Urine was collected for up to 72 hours (12 time points) and MA contents were measured after purifying and enrichment by solid phase extraction (SPE) [Fuhr et al., 2006]. Levels of 3-HPMA and of MAs derived from AA (N-acetyl-S-(2-carbamoylethyl)-cysteine (AAMA)) and glycidamide (N-acetyl-S-(2-hydroxy-2-carbamoylethyl)-cysteine (GAMA)) were determined by liquid chromatography tandem mass spectrometry (LC-MS/MS), and urinary concentrations were standardized by reference to urinary creatinine. The maximal urine concentrations found for 3-HPMA, AAMA, and GAMA were (mean ± SD) 146 ± 86, 2.5 ± 0.8, 0.14 ± 0.07 µmol/g creatinine, respectively and elimination half lives were 5, 12, and 38 hours. The AA uptake with a 150 g meal of potato crisps was about 1 mg, equivalent to 12.4 µg/kg body weight. The predose values for the sum of AAMA and GAMA were 0.15, that for 3-HPMA 35.9 µmol/g creatinine. On the basis of the AUC values of MAs excreted in urine, the total excretion of 3-HPMA was about 15 times higher than that of AAMA plus GAMA. Thus, the exposure to AC from the test meal was at least one order of magnitude higher than exposure to AA. The question as to what extent AC exposure has to be taken into account when considering risk assessment by heat induced toxicants has not been addressed before.

Synthesis and characterization of polyethylene modified through phase-transfer-catalyzed graft copolymerization

In an effort to impart biodegradability, polyethylene (PE) was modified through the graft copolymerization of vinyl monomers such as acrylamide (AAm) and acrylic acid (AAc) by a phase-transfer-catalyst method. The grafting percentage of AAm and AAc for PE was found to be dependent on the dibenzoyl peroxide concentration, monomer concentration, time, temperature, and concentration of the phase-transfer catalyst. Some AAm- and AAc-grafted PE samples were prepared by chemical, UV, and γ-radiation methods. The biodegradation of samples of PE, polyethylene-g-polyacrylamide, and polyethylene-g-poly(acrylic acid) prepared by all these methods was studied. The weight loss of the samples over a period of time was observed with soil-burial tests. The grafted samples prepared by the phase-transfer-catalyst method showed better biodegradation results than those prepared by other methods of grafting. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Phenacylpyridinium Oxalate as a Novel Water-Soluble Photoinitiator for Free Radical Polymerization

Phenacylpyridinium oxalate (PPOx) was synthesized by counter anion exchange reaction of phenacylpyridinium bromide (PPBr) with potassium oxalate. Radicals formed from the photolysis of PPOx in aqueous solutions were capable of initiating polymerization of hydrophilic monomers such as acrylamide (AAm), 2-hydroxyethyl methacrylate (HEMA) and N-vinyl pyrrolidone (NVP). Direct decomposition of excited phenacylpyridinium ion as well as electron transfer and cleavage reactions involving both pyridinium and oxalate ions were proposed for the initiation step.

Microgel, nanogel and hydrogel–hydrogel semi-IPN composites for biomedical applications: synthesis and characterization

Quaternary ammonium salt hydrogels from a cationic monomer, (3-acrylamidopropyl)-trimethylammonium chloride (APTMACl), in a variety sizes such as bulk, micro- and nano- has been prepared. The synthesis of micro- and nanogels were carried out in the microenvironment of water-in-oil microemulsions using two types of surfactants, namely, L-α- phosphatidylcholine (lecithin) and dioctyl sulfosuccinate sodium salt (AOT). Additionally, hydrogel–hydrogel composite semi-interpenetrating polymer networks (semi-IPN) was synthesized by dispersing previously prepared micro/nanogel into neutral monomers such as acrylamide (AAm) or 2-hydroxylethyl methcarylate (HEMA) before network formation. Hydrogel swelling and pH response behaviors have been investigated for bulk gels. Morphology, structure, and size of nano-, micro- and bulk materials were explored utilizing transmission electron microcopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). It was confirmed with gel electrophoresis that completely charged nanogel form a strong complex with DNA.

Influence of Secondary Components on the Synthesis of Self-Cross-Linked N-Isopropylacrylamide Microgels

This work presents systematic studies of cross-linker-free microgels formed by copolymerization of N-isopropylacrylamide (NIPAAm) and various secondary monomer components in water under standard reaction conditions. The sizes, solid densities, and volume phase transitions of these particles have been characterized through static and dynamic laser light-scattering experiments. We find that introducing a hydrophobic component, for example, styrene (St) or methyl methacrylate (MMA), leads to particles with smaller sizes and higher solid densities, while the volume phase transition shifts to lower temperatures. On the other hand, introducing a hydrophilic component such as acrylamide (AAm) or acrylic acid (AA) leads to larger particles with lower solid densities and a volume phase transition that shifts to higher temperatures and is broadened. The molar mass changes little in either case. Introducing a charged component such as sodium styrene sulfonate (NaSS) or poly(sodium styrene sulfonate) (PNaSS) leads to a sharp decrease in molar mass and particle size, and a very broad phase transition. These trends provide good guidance for synthesizing both self-cross-linked and cross-linked copolymerized microgels of different properties.

Functionalizing of polyurethane surfaces by photografting with hydrophilic monomers

Poly(ester urethane) (PU) with functional groups (amide, hydroxyl, carboxyl) on surfaces were prepared by grafting monomers such as acrylamide (AAm), hydroxyethyl acrylate (HEA), and methacrylic acid (MAA) onto the PU membranes. Grafting copolymerization was carried out by the combined use of photooxidization and UV irradiation grafting. The PU membrane was photooxidized in hydrogen peroxide solution under UV light to yield hydroperoxide groups on the surface and then irradiation grafting with monomer in water. The ATR-FTIR spectrum, X-ray photoelectron spectroscopy characterized the grafted copolymers and verified the occurrence of grafting copolymerization. The results showed that the content of hydroperoxide groups yielded was dependent on the photooxidization time and reached maximum at about 8 h. Grafting copolymerization was enhanced when irradiating by UV light. The degree of grafting was increased with the increase of content of hydroperoxide groups, irradiation time, and monomer concentration. The grafting copolymerization was enhanced when an appropriate amount of ferrous ions was added. After grafting, the wettability of PU and the water absorption percentage increased with the degree of grafting. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2505–2512, 2000

Photoinduced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine on polyethylene membrane surface for obtaining blood cell adhesion resistance

Phospholipid polymer, poly[2-methacryloyloxyethyl phosphorylcholine (MPC)], was grafted with polyethylene (PE) membrane using photoinduced polymerization technique to make the membrane resistant to cell adhesion. The water contact angle on the PE membrane grafted with poly(MPC) decreased with an increase in the photopolymerization time. This decrease corresponded to the increase in the amount of poly(MPC) grafted on the PE surface. The same graft polymerization procedure was applied using other hydrophilic monomers, such as acrylamide (AAm), N-vinylpyrrolidone (VPy) and methacryloyl poly(ethylene glycol) (MPEG). These monomers were also polymerized to form grafted chains on the PE membrane, and the grafting was confirmed with X-ray photoelectron spectroscopy. Analysis of amount and distribution of plasma proteins at the plasma-contacting surface of the original and the modified PE membranes were analyzed using immunogold assay. The grafting of poly(MPC) and poly(VPy) on PE membrane reduced the plasma protein adsorption significantly compared with that on the original PE membrane. However, the PE membranes grafted with poly(AAm) or poly(MPEG) did not show any effects on protein adsorption. Platelet adhesion on the original and modified PE membranes from platelet-rich plasma was also examined. A large number of platelets adhered and activated on the original PE membrane. Grafting with poly(AAm) did not suppress platelet adhesion, but grafting with poly(MPC) or poly(VPy) on the PE membrane was effective in preventing platelet adhesion. It is concluded that the introduction of the phosphorylcholine group on the surface could decrease the cell adhesion to substrate polymer.