Transmission-electron microscopic observations of freeze-etched polyacrylamide gels
106
Citation
34
Reference
10
Related Paper
Citation Trend
Keywords:
Polyacrylamide
Agar gel
Polyacrylamide is a polymer of controllable molecular weight formed by the polymerization of acrylamide monomers available in one of three forms: solid (powder or micro beads), aqueous solution, or inverse emulsions (in water droplets coated with surfactant and suspended in mineral oil). Residual acrylamide monomer is likely an impurity in most Polyacrylamide preparations, ranging from <1 ppm to 600 ppm. Higher levels of acrylamide monomers are present in the solid form compared to the other two forms. Polyacrylamide is reportedly used in 110 cosmetic formulations, at concentrations ranging from 0.05% to 2.8%. Residual levels of acrylamide in Poly acrylamide can range from < .01 % to 0.1 %, although representative levels were reported at 0.02% to 0.03%. Because of the large sizes of Polyacrylamide polymers, they do not penetrate the skin. Polyacrylamide itself is not significantly toxic. For example, an acute oral toxicity study of Polyacrylamide in rats reported that a single maximum oral dose of 4.0 g/kg body weight was tolerated. In subchronic oral toxicity studies, rats and dogs treated with Polyacrylamide at doses up to 464 mg/kg body weight showed no signs of toxicity. Several 2-year chronic oral toxicity studies in rats and dogs fed diets containing up to 5% Polyacrylamide had no significant adverse effects. Polyacrylamide was not an ocular irritant in animal tests. No compound-related lesions were noted in a three-generation reproductive study in which rats were fed 500 or 2000 ppm Polyacrylamide in their diet. Polyacrylamide was not carcinogenic in several chronic animal studies. Human cutaneous tolerance tests performed to evaluate the irritation of 5% (w/w) Polyacrylamide indicated that the compound was well tolerated. Acrylamide monomer residues do penetrate the skin. Acrylamide tested in a two-generation reproductive study at concentrations up to 5 mg/kg day x in drinking water, was associated with prenatal lethality at the highest dose, with evidence of parental toxicity. The no adverse effects level was close to the 0.5 mg/kg day x dose. Acrylamide tested in a National Toxicology Program (NTP) reproductive and neurotoxicity study at 3, 10, and 30 ppm produced no developmental or female reproductive toxicity. However, impaired fertility in males was observed, as well as minimal neurotoxic effects. Acrylamide neurotoxicity occurs in both the central and peripheral nervous systems, likely through microtubule disruption, which has been suggested as a possible mechanism for genotoxic effects of acrylamide in mammalian systems. Acrylamide was genotoxic in mammalian in vitro and in vivo assays. Acrylamide was a tumor initiator, but not an initiator/promoter, in two different mouse strains at a total dose of 300 mg/kg (6 doses over 2 weeks) resulting in increased lung adenomas and carcinomas without promotion. Acrylamide was tested in two chronic bioassays using rats. In one study, increased incidence of mammary gland tumors, glial cell tumors, thyroid gland follicular tumors, oral tissue tumors, uterine tumors and clitoral gland tumors were noted in female rats. In male rats, the number of tumors in the central nervous system (CNS), thyroid gland, and scrotum were increased with acrylamide exposure. In the second study, using higher doses and a larger number of female rats, glial cell tumors were not increased, nor was there an increase in mammary gland, oral tissue, clitoral gland, or uterine tumors. Tumors of the scrotum in male rats were confirmed, as were the thyroid gland follicular tumors in males and females. Taken together, there was a dose-dependent, but not statistically significant, increase in the number of astrocytomas. Different human lifetime cancer risk predictions have resulted, varying over three orders of magnitude from 2 × 10 3 to 1.9 × 120 6. In the European Union, acrylamide has been limited to 0.1 ppm for leave-on cosmetic products and 0.5 ppm for other cosmetic products. An Australian risk assessment suggested negligable health risks from acrylamide in cosmetics. The Cosmetic Ingredient Review (CIR) Expert Panel acknowledged that acrylamide is a demonstrated neurotoxin in humans and a carcinogen in animal tests, but that neurotoxic levels could not be attained by use of cosmetics. Although there are mechanisms of action of acrylamide that have been proposed for tumor types seen in rat studies that suggest they may be unique to the rat, the Panel was not convinced that these results could be disregarded as a species-specific finding with no relevance to human health and safety. Based on the genotoxicity and carcinogenicity data, the Panel does not believe that acrylamide is a genotoxic carcinogen in the usual manner and that several of the risk assessment approaches have overestimated the human cancer risk. The Panel did conclude, however, that it was appropriate to limit acrylamide levels to 5 ppm in cosmetic formulations.
Polyacrylamide
Cite
Citations (128)
Abstract Linear polyacrylamide has been used to increase the tensile strength and stability of low percentage acrylamide gels in the range of 2.5 to 6.0 % w/v acrylamide. This added strength allows handling and staining of the gel without the excessive difficulty which is normally incurred when working in this range. Addition of up to 0.6 % w/v of linear polyacrylamide gives no pore size reduction. While addition of linear polyacrylamide to acrylamide gels using bisacrylamide as a crosslinker has a hazy appearance, the use of diallyltartardiamide as a crosslinker gives the desired clarity without loss of large pore size and improves adherence to glass walls. A further advantage of acrylamide gel matrices is that the traditional methods of silver staining can be used for detection of DNA. Thus, adding linear polyacrylamide to an acrylamide gel using diallytartardiamide as a crosslinker allows easy use of low percentage acrylamide gels for separation and detection of DNA fragments in the range of 70 to 2500 base pairs.
Polyacrylamide
Linear range
Cite
Citations (8)
Polyacrylamide
Cite
Citations (5)
Immobilization in polyacrylamide gel is a technique based on the polymerization of acrylamide with N,N′-methylene-bis-acrylamide (Bis) as the cross-linking agent. The degree of cross-linking is controlled by adjusting the ratio of acrylamide to Bis used. Being nonionic in nature, polyacrylamide is the most widely used matrix for entrapping enzymes.
Polyacrylamide
Methylene blue
Cite
Citations (1)
The impurities generated from the preparation process of acrylamide greatly effected on the properties of polyacrylamide.Researches showed that reducing the impurities containing in monomers was necessary to obtain polyacrylamide with satisfactory quality.In this article,experimental results were showed that impurities containing in acrylamide were reduced effectively by optimizing the parameters of equipment and technology and improvement of refining during the production of both acrylonitrile and acrylamide.The experimental polymerization of acrylamide showed that the new acrylamide produced after technology optimization can be used to synthesize polyacrylamide with high quality.
Polyacrylamide
Cite
Citations (1)
Polyacrylamide
Agar gel
Cite
Citations (65)
Abstract The outer membrane protein (OMP) profiles of 23 blood isolates of Acinetobacter baumannii representing all the different antimicrobial susceptibility patterns observed during a 3‐year period in a Spanish hospital were studied. OMPs extracted from envelopes of sonicated cells after solubilisation with 2% of N‐lauryl‐sarcosinate were analysed by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE) using the Laemmli's buffers. Eight running gel systems differing in the concentration of polyacrylamide (8%, 10% and 12%) and in the absence or presence of urea (4 M and 6 M ) were used in a preliminary study analysing the OMP profiles of four clonally unrelated strains of A. baumannii . When this study was completed, the OMPs of the 23 A. baumannii were analysed in 10% SDS‐polyacrylamide gels with 6 M urea and in 12% SDS‐polyacrylamide gels. Ten OMP profiles were observed in 10% SDS‐polyacrylamide gels with 6 M urea, whereas only 5 OMP profiles were visualised using 12% SDS‐polyacrylamide gels. The OMP profiles obtained in 10% SDS‐polyacrylamide gels with 6 M urea only partially correlated with those observed in 12% SDS‐polyacrylamide gels. In conclusion, the use of 10% SDS‐polyacrylamide gels with 6 M urea is recommended for the study of OMP profiles of A. baumannii .
Polyacrylamide
Acinetobacter baumannii
Sodium dodecyl sulfate
Cite
Citations (19)
The copolymerization reaction between gomuti starch and acrylamide was initiated using (NH4)2S2O8 as initiator under microwaves heating at 60~80 . The analysis of the Fourier transform-infrared spectroscopy and Scanning electron microscopy showed that the product is gomuti-graft-polyacrylamide. The productivity of graft copolymer and the conversion rate of acrylamide vary with the weight ratio of acrylamide and gomuti starch (AM/GOM). They reach maximum value when AM/GOM≈2.5. The flocculating test showed that in water of yellow mud , the turbidity removal rate of gomuti-graft-polyacrylamide is better than that of polyacrylamide.
Polyacrylamide
Turbidity
Cite
Citations (0)
Abstract The purpose of this paper is to present information gathered regarding, in general, the physical characteristics, and, in particular, the possible toxic nature of polyacrilamides. A short discussion of the properties and toxicity of the acrylamide monomer is also included. The United States government, specifically the Food and Drug Administration and the Environmental Protection Agency, already regulates several uses of polyacrylamide; criteria and standards have been established based on numerous toxicological studies of both polyacrylamide and acrylamide. These studies are reviewed and summarized. The regulations generally restrict both the amount of residual acrylamide monomer in the polyacrylamide and the amount of polymer that may be used in the specified application. By imposing this type of restriction, a maximum limit on the amount of acrylamide in contact with food or drinking water can be indirectly achieved.
Polyacrylamide
Cite
Citations (73)
Polyacrylamide
Depolymerization
Distilled water
Degradation
Cite
Citations (0)