JP2009534058A - Improved fibrin sealant composition and use thereof - Google Patents

Abstract

  The wound healing process can be reinforced by the addition of fibrin sealant. Depending on the sealant composition and method of application, the wound healing process and tissue regeneration may be further facilitated. The present invention provides improved sealant compositions and uses thereof.

Description

BACKGROUND OF THE INVENTION The overall wound healing process is a complex series of events that begins at the time of injury and can last for months to years. During the first 2-5 days, called the inflammatory phase, vasoconstriction, platelet condensation and thromboplastin clot formation occur, followed by inflammation characterized by vasodilation and phagocytosis. The next about 3 weeks, called the proliferative phase, begins with granulation where fibroblasts place the collagen bed, then the abnormal capillaries are filled and new ones are formed. Shrinkage damage edges are stitched together and the surface is covered with cells during epithelialization. The rebuilding phase can last from 3 weeks to 2 years. Here, new collagen is formed which increases the tensile strength.

Conventional fibrin sea lanterns, also called fibrin adhesives or fibrin glues, are also based on the polymerization of fibrinogen monomers to insoluble net marks (clots). This process is initiated when thrombin cleaves fibrinogen to become a fibrin II acid-soluble monomer and when thrombin activates factor XIII to factor XIIIa in the presence of Ca ⁺⁺ . The fibrin II acid-soluble monomer is then converted to an acid-insoluble crosslinked fibrin II polymer by Factor XIIIa.

  The use of fibrin sealants has been described for various medical means such as hemostatic agents, excess liquid absorbents, surgical adhesive barriers, wound dressings and bioactive agent delivery vehicles. Many methods of applying fibrin sealants are known in the art. They have all been developed for the rapid polymerization of fibrin sealants after mixing the fibrinogen and thrombin components. In one method, the mixture must be filled into a suitable size syringe and quickly applied to the desired site. Another method uses a double barrel syringe. Other methods employ a droplet delivery system or a spray application system. Some of these methods require special applicators. In still other methods, the components are bound to a carrier material, or one or more of the components may be in a non-liquid form, such as a powder. Biocompatible and biodegradable polymers have been identified as suitable carrier materials for fibrin sealant components. Such polymers offer the advantage that fibrin sealant fibers are pre-prepared and activated when placed at the injury site (US Pat. No. 6,503,527). Examples of useful polymers are polyglucosamine type materials such as hyaluronic acid (HA) and chitin / chitosan. HA has also been described as a preferred viscosity-enhancing polymer to prevent migration of the fibrin sealant from the site of application (EP 0590015).

  In addition to the uses described above, polyglucosamine type materials may have other advantages. For example, HA has been used in plastic surgery for removal of sputum, and doctors have infused HA directly into the synovial fluid of the knee as a treatment for osteoporosis for the past 20 years. However, the bioavailability of HA itself is limited due to its fast turnover and short half-life. Chitosan has been used as a dietary supplement to lose weight, but has also been found useful in wound healing (US Pat. No. 4,532,134).

  In addition to controlling hemostasis, it is further desirable to stimulate wound healing by providing the most likely condition for tissue regeneration, thereby promoting wound healing. Cell therapy and the use of typical growth factors are increasingly being used in current therapies where it is difficult to heal the injury. Growth factors can act synergistically with surgical debridement in healing wounds.

  Various types of substances have been tested as vehicles for cell or growth factor delivery, and no one has shown to be optimal. However, self-fibrin is thought to be useful for the delivery of self-keratinocytes (Grant 2002 Br J Plast Surg vol. 55: 219-227). Furthermore, autologous fibrin is now being developed to include and deliver a family of platelet-derived growth factors.

  The conversion of fibrin monomer by fibrin-cleaving agent into an insoluble network of polymerized fibrin is a rapid process and thus requires the preparation of a fibrin sealant mixture immediately before use. Fast polymerization can cause application problems due to clogging of the applicator and further difficulties in applying the correct dosage form to obtain the desired tensile strength of the fibrin sealant. Accordingly, fibrin sealant compositions have been employed that have been delivered by means of a solid phase carrier material wherein one or more of the components included is a solid phase, such as a fiber, sheet or powder. Such partially solid compositions can be prepared at a suitable time prior to use due to delays in the initiation of the polymerization process. These partially solid phase fibrin sealant compositions may appear to be more easily handled by medical professionals, but are also limited by certain limitations. For example, the use of other components suitable for tissue regeneration, such as fibrin sealant as a vehicle for cells, may not be compatible with a semi-solid phase or non-water soluble environment. In addition, liquid phase fibrin sealant compositions are more easily adapted to damaged edges than films or sheets. Accordingly, there remains a strong need for liquid fibrin sealant compositions and simple methods of their application.

BRIEF SUMMARY OF THE INVENTION In a first aspect, the present invention provides a liquid phase composition wherein, when applied to a desired site, the liquid component of the composition is a fibrin monomer or polymer, a fibrinogen-cleaving agent and a polyglucosamine. A fibrin sealant containing the mold material is formed.

  In a second aspect, the invention relates to a method of making the composition, wherein the components of the composition are not polymerized by storage in a low pH buffer until use.

  In a third aspect, the invention provides a method of applying the composition comprising providing a component of the composition, comprising providing an applicator device, the device comprising at least two reagent outlets and at least one reagent outlet. It relates to said method comprising an air outlet and applying the components of the composition to the desired site using an applicator device.

  In a fourth aspect, the present invention relates to the use of the composition to support cell growth.

  The present invention will be described in detail with reference to the following drawings.

DETAILED DESCRIPTION OF THE INVENTION The present invention is described in detail below.
One aspect of the present invention is a liquid phase composition, wherein the liquid component of the composition is partially applied at least one minute after application to the desired site upon application of the composition to the desired site. It relates to said composition which forms a fibrin sheeran comprising a fibrin monomer or polymer, a fibrinogen-cleaving agent and a polyglucosamine-type substance which is crosslinked or partially polymerised.

  The ability of a liquid fibrin sealant composition is determined by its physical properties, such as its ability to adhere to an application site without moving from place to place, elasticity and tensile strength, formed during polymerization. Clinical applications call for the instantaneous polymerization of a fibrin sealant having specified physical properties. Therefore, the time required to handle the fibrin sealant must be balanced.

  As used herein, “partially crosslinked or partially polymerized” indicates that the clot formation process has not been fully completed.

  The liquid composition of the present invention is suitable for most applications because the fibrin sealant is compatible with the application site. Rapid polymerization ensures that the fibrin sealant remains at the application site and is not removed by bodily fluids or target movement. As such, the present invention does not require the addition of ingredients to provide increased viscosity or carrier material. One or more applications of the liquid phase composition can create a fibrin sealant structure having the desired elasticity and tensile strength.

  “Fibrin” as used herein means fibrin, fibrin I or fibrin II. As used herein, “fibrinogen cleaving agent” means an enzyme capable of cleaving peptide A or peptide B or both from fibrinogen. A fibrinogen-cleaving agent commonly used in fibrin sealants is thrombin, which can be any suitable source, such as an enzyme from human or bovine, snake venom, such as batroxobin, carobin, fibrozyme, and the American Hub Harax. Obtained from snake-derived enzymes.

  As used herein, “polyglucosamine-type substance” means a molecule that is a repetitive part of a molecule where the glucosamine is. It includes biocompatible and bioabsorbable materials such as hyaluronic sun, chitin / chitosan and their derivatives.

  Chitin is widely distributed in the plant and animal kingdoms. Its main function is to provide structural and skeletal supports. Chitin is a linear homopolymer of β-D (1-4) linked to 2-acetamido-2-deoxy-D-glucopyranose (N-acetylglucosamine) units. A part, typically about 15%, of N-deacetylated, fully acetylated polymer is called chitan and fully deacetylated polymer is called chitosan. Is done.

  Hyaluronic acid (HA), also called hyaluronan, is a linear polymer of disaccharide repeating units, D-glucuronic acid and N-acetyl D-glucosamine. This mucopolysaccharide has been shown to have different biological properties depending on the molecular weight. HA has an unusually fast rate turnover of 2-5 minutes in animal tissue and is removed by degradation over time, even when it has a maximum molecular weight. Furthermore, the viscosity of the high molecular weight solution presents a major problem during application.

  The present invention demonstrates in Example 1 that a polyglucosamine such as HA is surprisingly trapped in a fibrin sealant clot, thereby delaying its fast turnover and short half-life. This provides a broader adoption in the selection and use of polyglucosamines of various molecular weights. The retention of HA in the fibrin clot allows the use of low molecular weight polyglucosamine in combination with a fibrin sealant, thereby making delivery more limited due to the low viscosity of the components.

  Infection is a challenge in the treatment of chronic injury, and therefore the use of antimicrobial agents is desirable. The examples of the present application demonstrate the antibacterial effect of chitosan. Other studies have also reported this property of chitosan (US Pat. No. 4,532,134). Furthermore, they found that when applied alone, chitosan reduced the tensile strength of the damage in the early stages of the wound healing process and did not provide a significant effect in later stages. . Early studies have shown that HA can help reduce the incidence of bacterial infections in bronchitis (Venge, P., 1996 Am J Respir Crit Care Med 153 (1): 312-6) . Thus, the simultaneous application of chitosan, HA or other polyglucosamine with a fibrin sealant may impart additional features of antimicrobial activity to the composition, as proposed in the present invention.

  High fibrin density can affect the growth and behavior of cells in the fibrin matrix, thereby affecting the wound healing process. Early studies have shown that high fibrin density results in a compressed network in which chondrocyte ingrowth is suppressed, but relatively low fibrin density increases HA, thereby further losing the cell's proliferating network. Yes. Therefore, it is desirable to expand the fibrin sealant network by incorporating a cytocompatible medium such as polyglucosamine to provide the best possible cell growth environment.

  In one embodiment of the invention, the polyglucosamine type material comprises at least 50% glucosamine monomer.

  In one embodiment of the present invention, the polyglucosamine type substance is selected from the group consisting of hyaluronic acid substances, hyaluronic acid derivatives, chitin substances, chitin derivative substances, chitosan substances and chitosan derivative substances.

  Polyglucosamine type materials also include materials comprising at least one modified monomer. The modification is, for example, chemical, and non-limiting examples of the principle target of modification are the carboxyl group present in N-acetyl D-glucosamine and the hydroxyl group present in D-glucuronic acid. This site can be terminally modified or reduce N-acetyl. In addition, the monomers can be modified by a number of crosslinking methods known in the art. Many of them are listed at www.glycoforum.gr.jp.

  In one embodiment of the invention, the polyglucosamine type material comprises a mixture of different materials.

  In one embodiment of the invention, the polyglucosamine-type material comprises a mixture of different molecular weights.

  In one embodiment of the invention, the polyglucosamine type material comprises a mixture of different materials and different molecular weights. The combined use of chitosan and HA protects HA from enzymatic hydrolysis, and therefore different materials of different molecular weights can be selected depending on the requirement for resistance to degradation of polyglucosamine type materials.

  In one embodiment of the invention, the degree of acetylation of the polyglucosamine type material is 0-100%.

  One embodiment of the invention relates to a composition further comprising a cell. The cells can be contained in solution with any other component, or the cells can be maintained in a separate solution. This can be determined depending on the origin of the cell and selection of the best environment for living cells. For example, platelets are isolated from the same source as fibrin and are therefore already present in fibrin-containing solutions. If the cells are cultured, the cells may be provided suspended in a cell growth medium, or the cells may be suspended in another suitable solution further comprising one or more other components. Also good.

  In one embodiment of the invention, the cell is selected from the group consisting of platelets, stem cells, fibroblasts, keratinocytes, chondrocytes and bone cells.

  One embodiment of the invention relates to a composition further comprising a growth factor. The growth factor may be contained in the solution with any other component or may be supplied in a separate solution. Such growth factors may assist in creating the most likely conditions for effector cells that are delivered to or already present at the injury site. The application of growth factors using fibrin sealant eliminates the step of the injury treatment method.

  In one embodiment of the invention, the growth factor is epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet derived growth factor (PDGF), transforming growth factor α (TGFα), transforming growth factor. Selected from the group consisting of β (TGFβ) and interleukin-1.

  One embodiment of the present invention is a method for preparing a composition, wherein the components of the composition are rendered unpolymerizable by storage in a low pH (the pH is 4) buffer until use. It relates to said method.

  In another embodiment of the invention, the components of the composition are rendered unpolymerizable by storage in two or more separate reservoirs until use.

  One embodiment of the present invention is a method of applying the composition to a desired site, comprising the following steps: providing a component of the composition; providing an applicator device, the device comprising at least 2 And a method comprising: applying one component outlet and at least one air outlet; and applying the components of the composition to a desired site using the applicator device.

  In one embodiment of the invention, the device comprises 3, 4 or 5 reagent outlets and at least one air outlet. The use of a spray applicator device, such as a Vivostat® application device (Dodd, RA, 2002 Technology and Health Care 10: 401-11) provides a convenient application, dosage and uniform mixture of ingredients.

  One embodiment of the invention relates to the use of a liquid phase composition that supports cell growth. This is done, for example, by adding additional (supporting) cells, growth factors, etc. to the composition to improve conditions for cell growth, cell activation, cell migration or cell differentiation.

  In one embodiment of the invention, the composition is used as a delivery vehicle for bioactive agents. Non-limiting examples may be antibacterial substances, drugs, cells, growth factors, hydrated substances and the like.

  In one embodiment of the invention, the composition is used as a surgical adhesion barrier.

  In one embodiment of the invention, the composition is used as an excess liquid absorbent. Hyaluronic acid is found in all connective tissues of the body that perform a specific function of lubrication. HA is also referred to as a hydrogel due to its ability to bind and retain large amounts of water.

  In one embodiment, the composition is used to reduce scar tissue formation. Application of chitosan alone has been shown to suppress fibrosis, which is considered to be scar tissue by fibroblasts, and an endothelial lining was observed instead (US Pat. No. 4,532,134). Thus, polyglucosamines such as chitosan, its derivatives or other polyglucosamines may reduce the formation of scar tissue.

  In the following, the invention will be described in more detail by way of non-limiting examples.

Example 1: Retention of hyaluronic acid (HA) in fibrin sealant
The objective is to determine the amount of HA that can be extracted from the fibrin clot and how much it will be retained thereby. Furthermore, the molecular weight of the extractable HA was determined.

The material three of fibrin clots were prepared:
Sample A labeled “0.484 g fibrin” contained 20 mg / ml fibrin.
Sample B labeled “0.568 g fibrin” contained approximately 10 mg / ml fibrin and 1% HA (v / v).
Sample C labeled “0.535 g fibrin” contained 20 mg / ml fibrin and 1% HA (v / v).

  HA with a molecular weight of 800 kDa (MAG 30014 supplied by NovoZymes) was co-applied in a 1% solution containing fibrin (fibrin: HA ratio of 1: 8). HA was extracted the same day as a clot preparation. All samples were obtained from the same donor.

Extraction method The clot was crushed with a spatula and then extracted with 10 ml PBS buffer at 4 ° C. for 4 × 24 hours with gentle agitation. The extract was collected by centrifugation (10 minutes, 3000 rpm, 4 ° C.), 5 ml deionized milliQH ₂ O was added, and then passed through a 0.45 μm syringe filter. The extract was stored at 4 ° C. before analysis after 2 days.

Quantification and characterization
Extracts were analyzed on SEG-MALLS-VISG (mobile phase: 150 mM NaCl, 50 mM NaH ₂ PO ₄ , pH 7.0, 0.5 ml / min) on a PL Aquagel OH-40 / 0H-50 / 0H60 column. Equipment: Waters Alliance HPLC equipment Waters 2410 RI detector and Wyatt MALLS detector.

  Quantification was performed by evaluating the RI signal. 0.5 ml of each sample was injected onto the column. Data was processed by ASTRA V software from Wyatt Technology Corp. Samples were labeled: A: 14919-037-1, B: 14919-037-2, and C: 14919-037-3.

The resulting chromatogram (see FIGS. 1 and 2) showed three different peaks for HA, including samples B and C, but peak 1 did not have sample A lacking HA.

  The results from SEG-MALLS-VISG analysis of the extracts are shown in Tables 1-5.

  The high molecular weight peak (peak 1) was identified as HA because it only appeared in samples B and C containing HA. Furthermore, when the molecular weight (Table 2), intrinsic viscosity (Table 3) and rotational diameter (Table 4) are compared, all show that peak 1 is actually HA. Peaks 2 and 3 are either proteins or protein fragments from the clot. The calculated quantities are summarized in Table 5.

  The total amount of extractable HA appears to be proportional to the amount of fibrinogen used. Clearly, a significant amount of HA is contained / bound in the fabric (approximately 90-95%).

Conclusion These results indicate that approximately 90-95% of the HA is retained in the fibrin clot. HA degradation was observed in extracts from clots prepared in the presence of 10 mg / ml fibrinogen, but no degradation was observed in extracts prepared in the presence of 20 mg / ml HA. .

Example 2: Antibacterial activity of fibrin or platelet-rich fibrin composition further containing chitosan The purpose of this test is to produce fibrin and staphylococcus aureus or escherichia coli on Muller Hinton agar. It was to test the antibacterial effect of platelet rich fibrin (PRF). Various concentrations of chitosan mixed with fibrin or PRF were tested.

  The agar diffusion used in this study is based on the diffusion of antibacterial substances from the tablets, or the antibacterial substances placed directly on the agar sprinkled with bacteria. Sown bacteria grow throughout the plate except in areas with micro-static concentrations of antimicrobial substance (s). This also results in the formation of a ring around the tablet or substance, the diameter of which is related to the ability of the added antibacterial substance to sown bacteria. The limitation of this method is the need for antimicrobial substances that can diffuse in the medium used (eg agar).

Fresh colonies of experimental bacteria S. aureus S29 (sensitive to antibiotics derived from KVL) and E. coli strain Top10 / F'Tet ^R (resistant to tetracycline) were sterilized 0.9% NaCl (Nycomed) with an OD ₆₂₅ of about 0.1 (Spectrophotometer Cecil 2040) was diluted, soaked in a bacterial solution with a cotton swab, and wiped several times on the agar plate to spread on the agar plate. Test substances were added to the plate within 30 minutes.

Fibrin and PRF are citrate buffers 04.41.002 (PRF) and 02.23.007 (RC), respectively, from donor BX051901 using RC Preparation Unit 05.17.003 or PRF Preparation Unit 05.17.003 (filtered out). Obtained. Fibrin or PRF was sprayed onto a ring made for this purpose (diameter 10 mm, height 3 mm, internal volume 235 mm ³ , see Fig. 3) and autoclaved using an Automated Processor Unit 75002 with a short tube. . The pH 10 buffer 03.11.001 was used for the pH shift. Polymerized fibrin or PRF tablets were transferred to a Mueller Hinton agar plate (batch number 2105008) with either S. aureus or E. coli.

  The addition of 1% or 2% (w / v) chitosan (0.02 g or 0.04 g Protasan B 0/500, Novamatrix batch number FP-412-03, each dissolved in 2 ml pH 4 buffer) This was done using a third syringe. The syringe was connected to an open valve port on the Vivostat® application device. This resulted in the addition of chitosan in an amount approximately one-seventh the final fibrin / PRF (0.14% and 0.28% final concentrations). Chitosan containing fibrin / PRF was prepared as described above and plated on agar plates. Additional controls were prepared by adding pure 2% chitosan to the agar surface or wells on the agar. All plates were made in two points. The plate was incubated at 37 ° C. for about 20 hours and then photographed (see FIGS. 4-6).

Conclusion This experiment confirms previous results demonstrating bacterial inhibition by fibrin or PRF clot. At the concentrations tested, chitosan alone was also inhibitory to bacterial growth. No significant synergistic effect of mixing fibrin or PRF with chitosan was detected.

  The control for complete resistance (E. coli with vancomycin or tetracycline) showed no inhibition, suggesting the antibacterial effect of PRF, fibrin and chitosan alone against the two bacterial strains. It is not known whether this is due to the diffusion of material on the surface or a simple “spread”.

Example 3: Platelet-rich fibrin with addition of chitosan or hyaluronic acid The aim is to test the water absorption of a composition comprising autologous platelet-rich fibrin (PRF) further comprising hyaluronic acid (HA) or chitosan.

1 day of experiment . 2% HA (0.08 g hyaluron from NovoZymes dissolved in NaCl batch number R052002) or 2% chitosan (0.08 g Protasan batch number FP-412-03, NovaMatrix dissolved in 4 ml pH 4 buffer 04.49.001) An automatic applicator Unit number 30002 with a short tube line was used to make molded fibrin and fibrin containing either. Fibrin was obtained from plasma donors AX052001 and AX052002. The pH 10 buffer 03.11.001 was used for the pH shift. The mass of the molded clot was determined (0 hour), the clot was immersed in physiological saline (see FIG. 7), and the mass was determined at intervals shown in Table 6 and FIG.

  2 days. After about 18 hours, the fibrin sample from the first plasma remained intact in saline, but the sample from the second plasma was completely lysed, probably due to differences in fibrinolytic activity. there were. After recording the mass of run 1, the clot was placed at 100% humidity. There was no obvious difference between the samples.

3 days. All the clots were clear and partially dissolved.
4th. All clots were dissolved except for jelly-like chitosan containing clot.

Conclusion This experiment shows that the addition of 2% chitosan or 2% HA did not affect the water absorption of fibrin clot and did not affect the fibrin dissolution of the clot.

FIG. 1 is a chromatogram showing the results of SEC-MALLS-VISC analysis of an extract from a clot with or without the addition of HA (samples C and A, respectively). Legend: Sample A; bottom line, Sample C; bottom line. FIG. 2 is a chromatogram showing the results of SEC-MALLS-VISC analysis of an extract from a clot to which HA was added (Sample B). FIG. 3 is a diagram of a ring for making polymerized fibrin or platelet rich fibrin clot. FIG. 4A is a view of a Muller Hilton agar plate with either S. aureus or E. coli plated. FIG. 4B is a view of a Muller Hilton agar plate with either S. aureus or E. coli plated. FIG. 5A is a view of a Muller Hilton agar plate with either S. aureus or E. coli seeded. FIG. 5B is a view of a Muller Hilton agar plate with either S. aureus or E. coli plated. FIG. 6A is a view of a Muller Hilton agar plate with either S. aureus or E. coli plated. FIG. 6B is a view of a Mueller Hilton agar plate with either S. aureus or E. coli seeded. FIG. 7 is an illustration of a molded clot. FIG. 8 is a diagram illustrating the weight loss of the formed clot within the first 18 hours.

Claims (22)

A liquid phase composition wherein the liquid component of the composition forms a fibrin sealant upon application to the desired site, wherein:
a. fibrin monomer or polymer;
b. fibrinogen-cleaving agent; and
c. The composition comprising a polyglucosamine type substance.   The composition of claim 1, wherein the fibrin sealant is partially crosslinked or partially polymerized at least 1 minute after application to the desired site.   The composition according to claim 1 or 2, wherein the polyglucosamine-type substance comprises at least 50% glucosamine monomer.   The composition according to any one of claims 1 to 3, wherein the polyglucosamine type substance is selected from the group consisting of hyaluronic acid substances, hyaluronic acid derivative substances, chitin substances, chitin derivative substances, chitosan substances and chitosan derivative substances. .   The composition according to claim 1, wherein the polyglucosamine type substance comprises one or more different substances.   The composition according to claim 1, wherein the glucosamine-type substance comprises one or more substances of different molecular sizes.   The composition according to any one of claims 1 to 4, wherein the glucosamine-type substance comprises one or more different substances having one or more different molecular sizes.   The composition according to any one of claims 1 to 7, wherein the degree of acetylation of the polyglucosamine type substance is 0 to 100%.   The composition according to any one of claims 1 to 8, further comprising a cell.   The composition according to claim 9, wherein the cells are selected from the group consisting of platelets, stem cells, fibroblasts, keratinocytes, chondrocytes and bone cells.   The composition according to any one of claims 1 to 10, further comprising a growth factor.   The growth factors include epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet derived growth factor (PDGF), transforming growth factor α (TGFα), transforming growth factor β (TGFβ) and interleukin − The composition of claim 11, wherein the composition is selected from the group consisting of 1.   13. A process for producing a composition according to any one of claims 1 to 12, wherein the components of the composition are not polymerized by storage in a low pH buffer until use.   The method of claim 13, wherein the pH is 4.   13. A method of making a composition according to any one of claims 1 to 12, wherein the components of the composition are not polymerized by storage in two or more separate reservoirs until use. A method of applying a composition according to any one of claims 1 to 12, comprising the following steps:
providing the components of the composition;
b. providing an applicator device, the device including at least two reagent outlets and at least one air outlet; and using the applicator device to apply the components of the composition to a desired site ,
Said method.   The method of claim 16, wherein the device comprises 3, 4 or 5 reagent outlets and at least one air outlet.   Use of a composition according to any one of claims 1 to 12 for supporting cell growth.   Use of a composition according to any one of claims 1 to 12 as a delivery vehicle for a bioactive substance.   Use of a composition according to any one of claims 1 to 12 as a surgical adhesion barrier.   Use of a composition according to any one of claims 1 to 12 as an excess liquid adsorbent.   Use of a composition according to any one of claims 1 to 12 for reducing scar tissue formation.

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