Electrospinning process for making a textile suitable for use as a medical article
The present invention is a bioactive, nanofibrous material construct which is manufactured using a unique electrospinning perfusion methodology. One embodiment provides a nanofibrous biocomposite material formed as a discrete textile fabric from a prepared liquid admixture of (i) a non-biodegradable durable synthetic polymer; (ii) a biologically active agent; and (iii) a liquid organic carrier. These biologically-active agents are chemical compounds which retain their recognized biological activity both before and after becoming non-permanently bound to the formed textile material; and will become subsequently released in-situ as discrete freely mobile agents from the fabric upon uptake of water from the ambient environment.
1. An electrospinning perfusion method for forming a fabricated textile suitable for use as a medical article, said method comprising the steps of:
dissolving a non-biodegradable polymer and a pre-chosen biologically-active agent in an organic solvent to provide an admixture, the dissolving step occurring at an ice-cold temperature;
permitting the admixture to warm to a temperature between about 20° C. and about 50° C.;
loading the admixture into an electrospinning perfusion assembly comprised of at least one perfusion instrument which can be set at a specified flow rate;
perfusing said admixture onto a target surface at the specified flow rate, the step of perfusing occurring at a temperature between about 20° C. and about 50° C. to provide a perfused material;
removing the perfused material from the target surface to form a nanofibrous fabricated textile.
2. The method as recited in claim 1 , wherein the nanofibrous fabricated textile has a longitudinal axis, the method further comprising the steps of:
stretching the nanofibrous fabricated textile along the longitudinal axis after it has been removed from the target surface to apply a set strain; and
removing residual organic solvent from the stretched nanofibrous fabricated textile while the set strain is applied.
3. The method as recited in claim 2 , wherein the step of removing the residual organic solvent is accomplished by treatment with ethanol.
4. The method as recited in claim 2 , wherein the nanofibers are tubes and, after the stretching step, the nanofibers have an inner diameter that remains uniform over their length, the inner diameter being less than 1 mm.
5. The method as recited in claim 1 , wherein the perfusion instrument has a needle, the method including the step of positioning the needle and the target surface a distance apart of between 10 cm and 40 cm.
6. An electrospinning perfusion method for forming a fabricated textile suitable for use as a medical article, said method comprising the steps of:
dissolving a non-biodegradable polyester or polyurethane and a pre-chosen biologically-active agent in hexafluoroisopropanol to provide an admixture, the dissolving step occurring at an ice-cold temperature;
loading the admixture into an electrospinning perfusion assembly comprised of at least one perfusion instrument which can be set at a specified flow rate, the perfusion instrument having a spinneret sized to produce nanofibers with a diameter of less than about 2 micrometers;
perfusing said admixture through the spinneret and onto a target surface at the specified flow rate, the step of perfusing occurring at a temperature between 15° C. and 30° C. to provide a perfused admixture comprising polymeric fibers with a diameter of less than about 2 micrometers;
removing the perfused admixture from the target surface to form a nanofibrous fabricated textile which consists essentially of the non-degradable polyester or polyurethane and the pre-chosen biologically-active agent, the biologically active agent being releasably entrapped within the non-degradable polyester or polyurethane.
7. The method as recited in claim 6 , wherein the ice-cold temperature is between 0° C. and 5° C.
8. The method as recited in claim 6 , wherein the nanofibrous fabricated textile has a longitudinal axis, the method further comprising the steps of:
stretching the nanofibrous fabricated textile along the longitudinal axis after it has been removed from the target surface to provide a set strain; and
removing residual hexafluoroisopropanol from the stretched nanofibrous fabricated textile while the set strain is applied.
9. The method as recited in claim 6 , wherein the biologically active agent is maintained at a temperature below about 50° C. during the steps of dissolving, loading, perfusing and removing such that the biologically active agent maintains the same biological activity after the method as it had before the method.
10. An electrospinning perfusion method for forming a fabricated textile suitable for use as a medical article, said method comprising the steps of:
dissolving a non-biodegradable polymer and a pre-chosen biologically-active agent in an organic solvent to provide an admixture, the dissolving step occurring at temperature of about 4° C.;
permitting the admixture to warm to a temperature between about 20° C. and about 25° C.;
loading the admixture into an electrospinning perfusion assembly comprised of at least one perfusion instrument which can be set at a specified flow rate;
perfusing said admixture onto a target surface at the specified flow rate, the step of perfusing occurring at a temperature between about 20° C. and about 25° C. to provide a perfused material;
removing the perfused material from the target surface to form a nanofibrous fabricated textile.