ES2541226B2 - Blood phantom - Google Patents

Abstract

A blood phantom comprising a mixture of a nonpolar solution, a polar solution and an amphipathic compound, wherein the apolar solution has a density less than the amphipathic compound and that the polar solution, and the amphipathic compound has a density greater than apolar solution and less than polar solution.

Description

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DESCRIPTION

Blood phantom

TECHNICAL SECTOR

The present invention relates to the hematological and clinical sector, in particular with the simulation of blood for in vitro experimentation, its use in clinical learning and development of clinical machinery.

PREVIOUS STATE OF THE TECHNIQUE

Blood is a fluid tissue that circulates in capillaries, veins and arteries of all vertebrates. It is a type of specialized connective tissue, with a liquid colloidal matrix and a complex constitution. It has a solid phase composed of leukocytes (or white blood cells) and erythrocytes (or red blood cells) among others, and a liquid phase, represented by the blood plasma. The solid phase constitutes about 45% of the blood, and 55% is represented by the blood plasma.

In the hematology sector, there is an increasing demand for blood simulators for use in in vitro experimentation, in clinical learning and in the development and calibration of clinical machinery. Some of the most sought-after characteristics of these simulators, such as in the case of manipulation and extraction of blood samples or in the handling of the centrifugation of blood samples, are that they have the rheological characteristics, such as viscosity, and density, similar to whole blood, red blood cells, leukocyte phase and plasma, in different working conditions.

Document ES 2343778 A1 discloses a phantom of human blood that reproduces the size of the solid elements of the solid phase, the percentage composition and the viscosity of the blood, by means of a colloidal Agar-Agar base in water, inert microparticles, and dye Red. This simulator has rheological characteristics similar to those of blood and density values similar to those of the blood elements.

EXHIBITION OF THE INVENTION

The object of the invention is to provide a blood phantom as described below.

The blood phantom of the invention comprises a mixture of an apolar solution, a polar solution and an amphipathic compound, wherein the apolar solution has a lower density than the amphipathic compound and that the polar solution, and the amphipathic compound has a higher density. that the apolar solution and less than the polar solution.

The polarity and density parameters of the invention favor similar behavior in processes of agitation and / or centrifugation of blood samples and manipulation of the different phases that form the blood sample, being useful in clinical learning, such as in learning the process of separation and extraction of platelets rich in growth factors, and / or the calibration of clinical machinery in which the density and / or viscosity of the blood sample and / or the three phases that compose it Be critical.

This phantom avoids the use of real blood samples, which in addition to requiring biosafety preventive measures, are a good of great value but limited. Another additional advantage is that this phantom is synthetic and biosafety, so it does not require protection mechanisms

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additional to those required to use a chemical compound.

These and other advantages and characteristics of the invention will become apparent in view of the figures and the detailed description of the invention.

DESCRIPTION OF THE DRAWINGS

Figure 1 shows a graphic representation of a blood phantom centrifuged in a test tube.

Figure 2 shows the viscosity values and the deformation rate of a blood phantom.

DETAILED EXHIBITION OF THE INVENTION

The inventors have developed a blood phantom characterized in that it comprises a mixture of a nonpolar solution, a polar solution and an amphipathic compound, wherein the apolar solution has a lower density than the amphipathic compound and that the polar solution, and the amphipathic compound has a density greater than the apolar solution and less than the polar solution.

In the context of the present invention the term "phantom" refers to a model or simulator that represents some system, organ or biofluid of a human or animal body.

Blood is a homogeneous colloidal fluid. If this blood is subjected to a centrifugation process, one of the most common clinical practices in the hematology sector, it is observed that it separates into three layers that reflect the heterogeneity of the components that form the blood, where the lower layer corresponds to the red blood cells, the intermediate to the leukocyte phase and the superior to the plasma. However, if it is agitated, it returns to obtain a homogeneous appearance.

Considering all these parameters, the inventors establish an apolar solution that simulates the blood plasma; a polar solution that simulates red blood cells; and an amphipathic or surfactant compound, which simulates the leukocyte phase. The surfactant influences by means of the surface tension on the contact surface between the two immiscible solutions, which by stirring causes an emulsion to be generated.

The density of the different parts that form the phantom is one of the parameters to simulate. In the present invention, the apolar solution has a density less than the amphipathic compound and that the polar solution, and the amphipathic compound has a density greater than the apolar solution and less than the polar solution.

Preferably, the density of the polar solution is approximately between 1.00 and 1.11 gr / cm 3, thus simulating the density of human red blood cells.

Sometimes it is also interesting to simulate viscosity, so the apolar solution, which simulates plasma preferably has a viscosity of approximately 1.05 to 1.70 mPa, and the polar solution, which simulates red blood cells, has preferably a viscosity of approximately 0.015 to 0.03 mPa.

Viscosity values are considered in the working temperature or phantom handling conditions.

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Therefore, the present invention is able to simulate the behavior of blood both at rest and centrifugal, being useful in clinical learning, as it can be in learning the process of separation and extraction of platelets rich in growth factors, and / or the calibration of clinical machinery in which the viscosity and / or density of the blood sample and / or the three phases that compose it is critical.

In figure 1, a centrifuged phantom is represented, in which polar solution 1, amphipathic compound 2 and apolar solution 3 are distinguished.

In a preferred embodiment of the invention, the apolar solution is in a proportion between 47 and 51% (v / v), preferably 49%, the polar solution is in a proportion between 47 and 51% (v / v), preferably 49 %, and the amphipathic compound between 1 and 3% (v / v), preferably 2%, the sum of the three being 100%. In this way the percentage amounts of the three phases of human blood are simulated.

Preferably, both the apolar and polar solution are liquid, which are characterized by being homogeneous, having the same properties throughout the sample.

As for the apolar solution, it preferably comprises at least one aliphatic alkane or a mixture of aliphatic alkanes. In one embodiment said aliphatic alkane has between 11 and 13 carbons, preferably 11 carbons. These alkanes are characterized by being liquid, having an apolar character and comprise a viscosity between 1.05 and 1.07 mPas, in a working condition in the range of 23-25 ° C. In another embodiment, said mixture of aliphatic alkanes has a mass fraction of approximately 0.4 to 0.6 of C18H38 in C9H20 or in C10H22, preferably 0.5.

Mass fraction means the mass of solute present per unit of dissolution mass (quotient between solute mass and dissolution mass).

With regard to the polar solution, it is preferably a polymer solution.

One of the properties of the polymer solutions is the viscosity, which depends on the chemical structure of the polymer, on the interactions with the solvent and on the molecular weight. Normally, a high molecular weight molecule in a good solvent acquires a large hydrodynamic volume and the viscosity of the solution increases. In the case of polyelectrolytes, the hydrodynamic volume depends, not only on the molecular weight, but also on the number and distribution of ionic groups in the polymer chain. Ionic groups can cause repulsion between the chains, which results in an expansion of the molecule and, consequently, an increase in the viscosity of the solution.

Examples of polymers include, without limitation, polyvinyl alcohol, polyvinyl acetate, polyethylene glycol, polyvinyl pyrrolidone, polyethanol or polyacrylamide. In the preferred embodiment, the polar solution comprises a polymeric solution of polyacrylamide in water, preferably in a mass fraction, approximately, between 0.25 and 0.30 of polyacrylamide in water.

The amphipathic compound is an emulsifier or emulsifier that reduces the surface tension of the different solutions that favors the creation of an emulsion. This amphipathic compound is preferably formed by at least one surfactant. Examples of surfactants include, without limitation, soaps and detergents.

In a preferred embodiment, the amphipathic compound is a mixture comprising water, sodium hydroxide, sodium chloride and oleic acid, preferably in a mass concentration,

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between 85% and 90%, preferably 87% (w / v) of water, between 1% and 3%, preferably 2.1% (w / v) of sodium hydroxide, between 0.1% and 0 , 5%, preferably 0.2% (w / v) of sodium chloride and between 8% and 12%, preferably 10% (w / v) of oleic acid.

Mass concentration is understood as the mass of solute present per unit volume of solution (ratio between mass of solute and volume of solution).

The present invention, in its emulsion state, has a Non-Newtonian behavior, that is, it is a fluid whose viscosity varies with temperature and time. As a result, a non-Newtonian fluid does not have a defined and constant viscosity value, unlike a Newtonian fluid.

Under working conditions between 23 and 25 ° C, the phantom preferably comprises a viscosity approximately, between 7mPa and 10 mPa, with a deformation rate of approximately between 150 seconds-1 and 250 seconds-1. In this way, the simulation of whole blood treated with heparin at rest in these working conditions is achieved.

Sometimes it is interesting that the phantom has a color, either to simulate the red color of the blood or by another color to distinguish it from a real blood sample, so that the present invention preferably comprises at least one dye.

In the preferred embodiment, it comprises at least the C18H14N2Na2O8S2 dye (also known as Allura Red) thus simulating the red color of blood and red blood cells.

Another advantage of the invention is that the manufacturing process of the invention does not present any complexity since it comprises mixing the different components and stirring or heating them in a water bath above 40 ° until a complete dissolution.

Although the present invention focuses on a blood phantom, the different parts that comprise said phantom also behave like plasma and / or red blood cell and / or leukocyte phase symptoms.

Next, an illustrative example is described that demonstrates the features and advantages of the invention, however, it should not be construed as limiting the object of the invention as defined in the claims.

Example:

Example 1: Obtaining a blood phantom for use at a working temperature of approximately 25 ° C.

For the preparation of the polar solution, 28 g of polyacrylamide were dissolved in 100 ml of water.

For the preparation of the amphipathic compound 25gr of sodium hydroxide, 2gr of sodium chloride and 125 ml of oleic acid were mixed in 1 liter of water.

The 4 ml of polar solution, 0.6 g of the amphipathic mixture, 4 ml of apolar component and 0.03 g of C18H14N2N2O8S2 were mixed, and stirred vigorously until completely dissolved.

Once mixed, the density and dynamic viscosity were measured, using an Anton Paar DMA 5000 densimeter and a Anton Paar AMVn ball broth micro-meter.

respectively, obtaining values of 1,039 gr / cm3 and 10.5 mPa.s with a deformation rate of approximately 150 seconds-1 and 250 seconds-1 at a working temperature of 25 ° C.

5 Figure 2 shows the evolution of the strain rate of the sample prepared in the example.

Claims (14)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 1. Blood phantom characterized in that it comprises a mixture of a nonpolar solution, a polar solution and an amphipathic compound, wherein the apolar solution is in a proportion between 47 and 51% (v / v), preferably 49%, the polar solution it is in a proportion between 47 and 51% (v / v), preferably 49%, and the amphipathic compound between 1 and 3% (v / v), preferably 2%, where the apolar solution has a density less than the compound amphipathic and that the polar solution, and the amphipathic compound has a density greater than the apolar solution and less than the polar solution. 2. Blood phantom according to claim 1, wherein said apolar solution has a viscosity of approximately between 1.05 and 1.70 mPa. 3. Blood phantom according to any of the preceding claims, wherein said polar solution has a viscosity of approximately 0.015 to 0.03 mPa. 4. Blood phantom according to any of the preceding claims, wherein the density of the polar solution is approximately between 1.00 and 1.11 gr / cm3. 5. Blood phantom according to any of the preceding claims, wherein the apolar solution comprises at least one aliphatic alkane or a mixture of aliphatic alkanes. 6. Blood phantom according to claim 5, wherein said aliphatic alkane has between 11 and 13 carbons, preferably 11 carbons. 7. Blood phantom according to claim 5, wherein said mixture has a mass fraction of approximately 0.4 to 0.6 of C18H38 in C9H20 or C10H22, preferably 0.5. 8. Blood phantom according to any of the preceding claims, wherein the polar solution is a polymer solution. 9. Blood phantom according to claim 8, wherein the polar solution comprises a polymeric solution of polyacrylamide in water, preferably in a mass fraction, approximately, between 0.25 and 0.30. 10. Blood phantom according to any of the preceding claims, wherein the amphipathic compound comprises at least one surfactant, preferably a soap or a detergent. 11. Blood phantom according to claim 10, wherein said surfactant is a mixture comprising water, sodium hydroxide, sodium chloride and oleic acid. 12. Blood phantom according to claim 11, wherein said mixture comprises approximately a mass concentration of between 85% and 90%, preferably 87% of water, between 1% and 3%, preferably 2.1% of hydroxide of sodium, between 0.1% and 0.5%, preferably 0.2% sodium chloride and between 8% and 12%, preferably 10% oleic acid. 13. Blood phantom according to any of the preceding claims, wherein the viscosity of said phantom is approximately between 7mPa and 10mPa. 14. Blood phantom according to claim 13, wherein said viscosity has a deformation rate of approximately 150 seconds-1 and 250 seconds-1. 5. Blood phantom according to any of the preceding claims, wherein It also comprises at least one dye, preferably C18H14N2Na2O8S2.