Chemical and photoelectron spectrometry analysis of the adsorption of phospholipid model membranes and red blood cell membranes on to chrysotile fibres

Our plain-English summary of Chemical and photoelectron spectrometry analysis of the adsorption of phospholipid model membranes and red blood cell membranes on to chrysotile fibres, by M.C. Jaurand, J.H. Thomassin, P. Baillif, et al (British Journal of Industrial Medicine, 1980).

The study

• Authors: M.C. Jaurand, J.H. Thomassin, P. Baillif, L. Magne, J.C. Touray, J. Bignon
• Journal: British Journal of Industrial Medicine
• Published: 1980;37(2):169-74
• Cited by: 30 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

A study of the interaction of phospholipid model membranes and red blood cell membranes with UICC A chrysotile fibres using chemical analysis and photoelectron spectrometry showed that the interaction agreed with an adsorption of the membranes on to the chrysotile fibres. The photoelectron spectrometry analysis allowed the statement that phospholipid model membranes are adsorbed as bilayer. Chemical analysis showed that for each milligram of chrysotile the amount of phospholipids adsorbed was about 155 microgram and the available surface for phospholipids was about 38 m/g. It was established that entire membranes were adsorbed. A mechanism for the haemolytic capacity of chrysotile is suggested.

In plain English

This laboratory study examined how chrysotile asbestos fibres (UICC A reference sample) take up membrane material. The authors mixed the fibres with artificial membranes (liposomes) of the phospholipid DPPC, or with human red blood cell membranes ('ghosts'), and measured what attached by chemical analysis and photoelectron spectrometry (XPS). In preliminary tests, DPPC uptake reached balance within minutes. Across five experiments, maximum uptake was 155 plus or minus 27 micrograms of DPPC per milligram of chrysotile. XPS calculations fitted DPPC lying on the fibres as a double layer (bilayer) rather than a single layer. Assuming each DPPC molecule covers 60 square angstroms in a bilayer, chemical analysis gave an estimated available fibre surface of about 38 square metres per gram. For red blood cell membranes, adsorption plotted against membrane concentration showed a two-part (biphasic) pattern. Proteins and phospholipids were both adsorbed, in a nearly constant ratio. Results varied between experiments, which the authors linked to fibre aggregation and membrane complexity. The authors suggested that chrysotile may break red blood cells by adsorbing phospholipids, then whole membranes, as haemoglobin is released, leaving the fibres unreactive.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory (in vitro) experiment measuring adsorption of membranes on to chrysotile fibres by chemical analysis and X-ray photoelectron spectrometry (XPS)
• Who was studied: No human or animal subjects. Suspensions of UICC A chrysotile fibres were tested with DPPC liposomes (model membranes) and with membranes (ghosts) prepared from human red blood cells, in laboratories in Creteil and Orleans, France.
• Exposure: UICC A chrysotile at a final concentration of 1 mg/ml, mixed with DPPC liposomes (0 to 400 micrograms DPPC per ml) or red blood cell ghosts (0 to 200 micrograms phosphatides per ml) and incubated for 15 minutes at 37 degrees C
• Main results:
  • In preliminary tests with 500 micrograms DPPC per ml, the balance between free and adsorbed DPPC was reached in the first minutes
  • Liposomes: from five experiments, the maximum adsorption capacity was 155 plus or minus 27 micrograms of DPPC per mg of chrysotile
  • Assuming bilayer adsorption, the XPS-derived area per DPPC molecule was 64 or 80 square angstroms, depending on the electron path length assumed. The authors noted this was very close to published values for lecithin. Assuming a single layer (monolayer) gave 24 or 19 square angstroms.
  • The authors concluded that, at maximum surface coverage, DPPC was adsorbed as a bilayer
  • The chrysotile surface available to DPPC was estimated by chemical analysis, assuming 60 square angstroms per DPPC molecule and bilayer adsorption. The estimate had a mean of 38 square metres per gram (range 27.5 to 44.4).
  • Liposomes at a chrysotile concentration of 1 mg/ml: the mean adsorption coefficient from four experiments was 0.044 ml per microgram, corresponding to 50% coverage at 23 micrograms per ml
  • Red blood cell ghosts: by chemical analysis, the adsorption isotherm (amount adsorbed against concentration) was biphasic
  • Ghosts: in two experiments, the ratio of protein adsorbed to phospholipid adsorbed stayed nearly constant as the amount of ghosts increased
  • Ghosts: the XPS nitrogen signal indicated that both proteins and phospholipids were adsorbed on the chrysotile fibres
  • The chrysotile surface appeared positively charged when uncovered, and DPPC adsorption decreased the surface charge
• The authors' conclusion: The authors suggested a possible mechanism for how chrysotile breaks red blood cells (haemolysis). An electrostatic interaction with the cell may be followed by adsorption of phospholipids, release of haemoglobin, and adsorption of the whole membrane. The membrane-covered fibres then become unreactive.
• Limitations the authors state:
  • Results differed between experiments, possibly because the available fibre surface depends on how far the fibres were opened up
  • Large variation in the ghost experiments may reflect the complex make-up of the membranes or uneven (heterogeneous) ghost preparations
  • The XPS data for ghosts could not be explained by a simple model
  • Because of variation between experiments, the strength of attraction (affinity) of phospholipids for chrysotile was hard to assess
  • The adsorption formula applies to dilute solutions, whereas high DPPC concentrations were used

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile, UICC.

Related studies

• Changes in lipid ordering of model phospholipid membranes treated with chrysotile and crocidolite asbestos — E.G. Gendek, A.R. Brody (1990)
• Surface interaction between chrysotile and solutions (dissolution and adsorption): systematic x-ray photoelectron spectroscopy studies — J.H. Thomassin, J.C. Touray, et al. (1980)
• Influence of the sialic acid content of the membrane on its susceptibility to chrysotile — J. Depasse (1982)
• Hemolysis by chrysotile asbestos fibers. I. Influence of the sialic acid content in human, rat, and sheep red blood cell membranes — J.P. Pelé, R. Calvert (1983)
• Inhibition by phospholipids of haemolytic action of asbestos — M.C. Jaurand, L. Magne, et al. (1979)
• In vitro reactivity of alveolar macrophages and red blood cells with asbestos fibres treated with oxalic acid, sulfur dioxide and benzo-3,4-pyrene — M.C. Jaurand, L. Magne, et al. (1981)

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