Film Including a Polysulfated Oligosaccharide and a Polycation and Method for Manufacturing Same

Abstract

The present invention relates to a nanofilm including at least one polycation and one polysulfated oligosaccharide. The present invention also relates to the nanofilms obtainable by simultaneously or alternately sputtering at least one polycation solution and at least one polysulfated oligosaccharide solution and to the use of said nanofilms on skin, skin conditions, wounds, or mucous membranes. The present invention also relates to a nanofilm for the use thereof in a method for releasing polysulfated oligosaccharide upon contact with exuding wounds.

Claims

1. A film comprising at least one polycation and one polysulfated oligosaccharide having one to four ose units, said film having a thickness between 1 nm and 10 m.

2. The film according to claim 1, wherein the polycation is present in a quantity of 10% to 90% by weight, and the polysulfated oligosaccharide is present in a quantity of 10% to 90% by weight in relation to the weight of the film.

3. The film according to claim 1, wherein the polycation is selected from the group consisting of poly(L-lysin), chitosan, collagen, branched poly(ethylene imine), poly(L-arginine), poly(allylamine) (PAH), and their mixtures.

4. The film according to claim 1, wherein the polysulfated oligosaccharide is a sucrose octasulfate.

5. The film according to claim 1, having a thickness of 10 nm to 8 m.

6. A film obtained by simultaneously or alternately sputtering, of at least one polycation solution and at least one polysulfated oligosaccharide solution.

7. The film according to claim 6, wherein the sputtered solutions include a pharmaceutically-acceptable environment.

8. The film according to claim 6, wherein the sputtering is carried out simultaneously.

9. A film obtained by alternate impregnation in at least one polycation solution and at least one polysulfated oligosaccharide solution.

10. The film according to claim 9, wherein the solutions include a pharmaceutically-acceptable environment.

11. A method for releasing a polysulfated oligosaccharide onto an exuding wounds, said method comprising: preparing a film according to claim 1, and contacting the film with an exuding wound to release the polysulfated oligosaccharide.

12. A device configured to protect skin, wounds or mucous membranes, said device comprising the film according to claim 1.

13. The film according to claim 2, wherein the polycation is present in a quantity of 30% to 70% by weight and the polysulfated oligosaccharide is present in a quantity of 30% to 70% by weight.

14. The film according to claim 3, wherein the polycation is poly(L-lysin) or branched poly(ethylene imine).

15. The film according to claim 4, wherein the sucrose octasulfate is potassium sucrose octasulfate.

16. The film according to claim 5, having a thickness of 50 nm to 5 m.

17. The film according to claim 5, having a thickness of 100 nm to 1 m.

18. The film according to claim 7, wherein the pharmaceutically-acceptable environment is water.

Description

EXAMPLES OF NANOFILMS ACCORDING TO THE INVENTION

[0072] The polycations which have been used are of synthetic origin, like poly(L-lysin) (polypeptide) or of natural origin, like collagen (COL, protein).

[0073] Potassium sucrose octasulfate (or KSOS) and the polycations have been prepared in ultra-pure water (with resistivity 18.2 M.Math.cm, Milli-Q-plus system, Millipore).

[0074] The construction of nanofilms has been done on silicon substrates (Wafernet INC, USA), cut beforehand using a diamond scraper into rectangles of around 22 cm.sup.2. Before use, the substrates have been treated with plasma cleaner (Harrick Plasma, USA) in order to remove impurities and make them hydrophilic. The gas used is oxygen contained in air.

[0075] Whichever the system studied, a first layer of branched poly(ethylene imine) (BPEI) has been deposited by dipping (5 minutes) the substrate in an aqueous BPEI solution followed by two rinses with water (each for 1 minute) and a drying with nitrogen. This first layer serves as a fastening layer favouring the construction of nanofilms.

[0076] The preparation of polycation/KSOS nanofilms by sputtering is defined below. A sputtering device including four airbrushes, connected to a compressed air inlet and placed at a distance of 25 cm from the substrate has been used.

[0077] Two airbrushes enable to sputter the two compounds in solution (KSOS and the chosen polycation). Two others enable to carry out the steps of rinsing and drying the deposits.

[0078] In order to evaluate the quantity of sputtered compounds, the sputtering flows are measured during each handling and are around 0.3 mL/s.

[0079] The substrate is rotated for a duration of the sputtering around 1000 rpm in order to obtain consistent deposits.

[0080] Several parameters have been studied: [0081] the type of sputtering (alternate or simultaneous) [0082] the concentration of substantive salt NaCl (0 and 150 mM) [0083] the type of polycations (synthetic or natural origin) [0084] the sputtered KSOS/polycation ratio

[0085] In order to measure the thickness of successive deposits on the silicon substrates, ellipsometry has been used.

[0086] Nanofilm stability tests have been carried out by putting a substrate of 22 cm.sup.2 in contract with 20 mL of physiological environment and environment simulating the wound for 45 minutes.

[0087] The physiological environment is modelled by a phosphate buffer at pH level 7.40.1 (phosphate buffer saline, PBS) obtained by diluting a 10 concentrated PBS solution containing Ca.sup.2+ and Mg.

[0088] The wound environment is modelled by a 5% mass NaCl and 5% mass CaCl.sub.2 dihydrate aqueous solution.

Example 1 According to the Invention: Poly(L-Lysin)/KSOS Nanofilms

[0089] PLL/KSOS nanofilms have been obtained after 25 simultaneous sputtering steps. The sputtering durations are as follows: 10 seconds for sputtered compounds; 5 seconds for rinsing, 5 seconds for drying.

[0090] The two compounds are used in an aqueous solution with 150 mM NaCl in substantive salt.

[0091] The optimisation of the construction has been obtained by making the KSOS concentration vary from 0.05 to 12 mg/mL for a PLL concentration of 0.2 mg/mL.

[0092] The construction optimum is obtained with 0.2 mg/mL in KSOS.

[0093] After developing PLL/KSOS nanofilms, their stability has been tested upon contact with the physiological environment and upon contact with the wound environment. To do this, each nanofilm with a size of 22 cm.sup.2 has been put in contact with 750 L of physiological environment or wound environment for 45 minutes followed by a step of rinsing with Milli Q water for 45 minutes.

[0094] PLL/KSOS nanofilms have a low loss of thickness (<10%) upon contact with the physiological environment, which means that nanofilms are stable upon contact with the physiological environment. In addition, the infrared spectroscopy shows that a low portion of the KSOS is released during this contact: the 1240 cm.sup.1 strip of KSOS slightly decreases.

[0095] However, upon contact with the wound environment, PLL/KSOS nanofilms are totally dissolved, thus releasing all the KSOS.

Example 2 According to the Invention: Study of Sputtering in Obtaining Poly(L-Lysin)/KSOS Nanofilms

[0096] In this example, the two compounds (PLL and KSOS) are used in an aqueous solution with 150 mM NaCl in substantive salt and at a concentration of 0.2 mg/mL.

[0097] PLL/KSOS nanofilms have been obtained after 16 alternate or simultaneous sputtering steps.

[0098] An alternate sputtering step is carried out as follows: the PLL solution then the KSOS solution is sputtered for 5 seconds followed by a step of rinsing for 5 seconds and of drying for 5 seconds.

[0099] A simultaneous sputtering step is carried out as follows: the PLL and KSOS solutions are simultaneously sputtered for 5 seconds, followed by a step of rinsing for 5 seconds and of drying for 5 seconds.

[0100] FIG. 1 represents the development of the thickness, in nm, of PLL/KSOS nanofilms according to the number of alternate and simultaneous sputtering steps in the presence of 150 mM NaCl. After 16 sputtering steps, the PLL/KSOS nanofilm reaches 36 nm by the simultaneous sputtering method and 10 nm by the alternate sputtering method.

[0101] The simultaneous sputtering method enables to obtain PLL/KSOS nanofilms with a given thickness with less steps than alternate sputtering. Indeed, all is needed is 3 simultaneous sputtering steps to obtain a 10 nm nanofilm, whereas 16 alternate sputtering steps are needed. Thus, the simultaneous sputtering method is economically advantageous (quicker and enables to use lower quantities of PLL and KSOS).

[0102] In addition, the thicknesses obtained in simultaneous sputtering have a better reproducibility (thickness error bar less than 10% thickness). Thus, the thickness of the nanofilm is easier to control with simultaneous sputtering.

[0103] In addition, the thicknesses obtained in alternate sputtering reach an upper value of 10 nm over the number of steps studied. This means that between 6 and 16 steps, the thickness no longer increases.

[0104] In conclusion, simultaneous sputtering enables a more effective control of the quantity of KSOS inserted in the nanofilm compared with alternate sputtering.

Example 3 According to the Invention: Branched Poly(Ethylene Imine) (BPEI)/KSOS nanofilms obtained by alternate impregnation

[0105] The two compounds (BPEI and KSOS) are used in an aqueous solution with 150 mM NaCl in substantive salt and at a concentration of 0.2 mg/mL.

[0106] BPEI/KSOS nanofilms have been obtained after 20 alternate impregnation steps. An impregnation step is carried out as follows: the support is dipped in one of the solutions (BPEI or KSOS) for 5 minutes, followed by a step of rinsing (dipping in a 150 mM NaCl solution) for 5 minutes and of drying for 5 seconds.

[0107] FIG. 2 represents the development of the thickness, in nm, of BPEI/KSOS nanofilms according to the number of alternate impregnation steps in the presence of 150 mM NaCl. After 20 alternate impregnation steps, the BPEI/KSOS nanofilm reaches 4.7 nm. As a comparison, the thickness of BPEI/KSOS nanofilms reach around 15 nm by alternate and simultaneous sputtering. One of the advantages of the impregnation method is the volume used in a compound solution. Indeed, for 20 deposit steps, the volume used for each compound is 10 mL in alternate impregnation and 30 mL in alternate and simultaneous sputtering.