IL41223A - Method of improving the surface properties of plastic articles used for the cultivation of living tissues and cells - Google Patents

Description

of titer plastic for the cells s Method of improving the surface properties of plastic articles 39297 This invention relates to a method of modifying the s face of a utensil made from a plastics material for the cultivation of living animal or human cells and so as to allow those cells and tissues to grow thereon as a In the last decades plastics materials have spread use for the production of numerous articles j previously were made from natural fibres the hvdrophobic nature of the surfaces of most plastics articles has prevented the full utilization of the otherwise valuable properties of plastics materials in several although synthetic fibres have found widespread use within the textile the hydrophobic nature of the surfaces of such fibres has prevented them from fully placing natural especially in articles which during use are in contact with the Also within the scientific and medical field the use of plastics materials has been hampered by the hydrophobic nature of plastics Plastics for example made from are unsatisfactory for the cultivation of living animal or human cells and tissue because their surface properties prevent liquids having high surface especially adhering to said living cells and tissue are unable to grow as a on the surface of such articles but curl up to form lumps which cannot be properly It has been of plastics articles for use in the medicxal field by ing such articles to a strong irradiation to obtain a tion dose of at least 5 In a radiation dose of about megarads is and even when using such a high radiation dose it has been found to It has now been found that the surface of plastics utensils can be made hydrophilic by a process which does not even require irradiation and if radiation is used then it requires a much lower radiation dose than the prior art the novel method results in the obtaining of reproducible The method of the invention comprises the steps of contact the surface of such a plastics utensil with a reactive medium containing an oxidant and H said medium being activatable 2 m diation so as to form free radicals and exposing said while the same remains in contact with said to ultraviol light at a wave length substantially the same as the absorption maximum of said plastics The chemically induced free process may be of various types dependent on the oxidant if the oxidant is a generation of free OH may be effected by the addition of an acid ferrous salt When using a concentration of about the plastics article is preferably in a mixture of solution and an acid ferrous salt and the mixture is subsequently heated to a temperature of about for about When initiating the free reaction by irradiation water is used as the free forming chemical The water may be sprayed onto the article in the form of a thin layer or the article or a part thereof may be covered by a thicker layer of of the order of 5 If a film of water is sprayed onto a plast article made from polystyrene and having a temperature of about radiation dose of about 7 megarads has been found to be satisfactorv in order to make the surface In case the water forms a layer of a thickness of about 5 a radiation dose of 7 megarads has also been foun to be The oxidant used is preferably gaseous oxygen for When a plastics article is exposed to ultr violet light in the presence of water and large amount of ozone are The ozone appears to be an important termediate compound in the reaction with the plastics material and in order to increase the amount of ozone it is pre ferred to start the operation of the ultraviolet lamp some time before the treatment of the plastics article is initiated Ozone decomposes by irradiation with a quantum cy of moles of ozone per light The presence of water increases the quantum efficiency When a mixture of ozone and water is the formation of free hydroxyl radicals can be These hydroxyl radicals are formed as a result of the decomposition of ozone into an oxygen molecule and an oxygen atom of which the latter reacts with water to form two hydroxyl It is assumed that one of the following reactions then takes Some of the hydroxyl radicals react directly with the plastics material to form a hydrophilic In case of polystyrene the hydroxyl radicals react with a particularly reactive form of the polystyrene formed as a result of the exposure to ultraviolet it has been that a reaction with the polystyrene also takes place even if the polystyrene has not been converted into such a reactive The hydroxyl radicals recombine in pairs form hydrogen peroxide which also decomposes when irradiated so as to form hydroxyl radicals which then may react with the plastics In another preferred embodiment of the invention the oxidant is potassium peroxydisuiphate which decomposes when being subjected to the influence of ultraviolet light so as to form sulphate ion The sulphate ion radicals then react with water to form hydroxyl radicals which can then react with the plastics material In case the article to be treated is made from the treatment of the polystyrene articles is ferably carried out in water saturated atmospheric air and a wave length of 254 When using a 15 watt low pressure mercury ultraviolet a significant effect is obtained within a time period of about The hydrophilie nature of the surfaces of plastics articles which have been treated by the method of the is evidenced by fact that the angle between the water surface and the surface of such plastics articles to which water has been is almost When said angle is above the surface is more or less The method of the invention particularly suitable for modifying the surfaces of articles made from satisfactory results are also obtained with articles made from such as and The invention will now be described in further detail with reference to the following EXAMPLE 1 25 ml of a mixture of and in a concentration 4 2 4 of were mixed with 2 ml of a solution A polystyrene article was immersed in said mixture and the ture was heated to for After this treatment the surface was EXAMPLE 2 Water was sprayed onto a surface of a polystyrene article and the article was subsequently irradiated at room ture so as to obtain a total radiation dose of 7 This treatment resulted in the obtaining of a hydrophilie EXAMPLE 3 25 ml of a solution was introduced into a styrene dish having a diameter of 9 cm so as to form a 5 mm layer on the bottom of said Subsequently the dish was so as to obtain a γ radiation dose of The surface of the polystyrene dish then became EXAMPLE 4 Water sprayed polystyrene dishes were introduced into a stream of water saturated atmospheric air at and diated by a UV lamp emitting light at a predominant wave length of 254 for 3 The surface thus treated was An ESCA spectrum of the surface shows that it contains EXAMPLE 5 Polystyrene dishes were introduced into a stream of water saturated and water saturated in a molar ratio of The articles were then irradiated at a temperature of by an UV lamp emitting light at a predominant wave length of 254 In order to investigate the changes of the surfaces of said articles by means of an ESCA the tion was continued for After this treatment the surface was The effected changes of the surface properties are denced by the ESCA spectrum which shows that the molar ratio of oxygen to sulfur in the surface layer is On the basis of said spectrum it can also be concluded that sulfur has been introduced as a substituent on the carbon sulfur peak at eV indicates a high sulfur valency which suggests that the sulfur has been introduced in the form of a sulfonic acid EXAMPLE 6 A polystyrene dish was filled with a solution of in M aqueous hydrochloric The dish was then subjected to ultraviolet light at a temperature of about The irradiation was continued for about 1 hour in order to permit an examination of the surface material with an ESCA spectrometer ESCA spectroscopy shows that this treatment introduces nitrogen into the surface of the polystyrene and thus renders it EXAMPLE 7 A water sprayed Nylon plate B3K on basis was introduced into a stream of water saturated atmospheric air at and by a UV lamp emitting light at a predominant wave length of 254 for 65 The surface thus treated was EXAMPLE 8 A water sprayed Nylon plate F 103 on caprolactam basis was introduced into a stream of water saturated atmospheric air at and irradiated by a UV lamp emitting light at a predominant wave length of for 65 The surface thus treated was EXAMPLE 9 A water sprayed polycarbonate plate on bisphenol was introduced into a water saturated stre of atmospheric air at and irradiated by a UV lamp emittin light at a predominant wave length of 254 for 65 The surface thus treated was insufficientOCRQuality

Claims (5)

1. ·. A method of modifying the surface of a utensil made from a plastics material for the cultivation of living animal or human cells and tissue, to allow said cells- or tissue to grow thereon as a monolayer, comprising contacting a surface of said utensil with a reactive medium containing an oxidant and H20, said medium being activatable by irradiation so as to form free radicals and exposing said surface, while the same remains in contact with said medium, to ultraviolet light at a wave length substantially the same as the absorption maximum of said plastics material.

2. A method as set forth in Claim 1 wherein said plastics material is selected from the group consisting of polycarbonate, nylon or polystyrene and said wave length is 254 my.

3. A method as set forth in Claim 1 wherein said oxidant is selected from the group consisting of oxygen, air, hydrogen peroxide and peroxydisulfates.

4. A method as set, forth in Claim 1 wherein said reactive medium is maintained in gaseous phase during said contacting and comprises oxygen and water vapor.

5. A method as set forth in Claim 4 wherein said gaseous reactive medium contains sulfur dioxide.