Covering and method using electrospinning of very small fibers

A method of covering an object with a material, comprising:

• charging a spinneret with an electric potential relative to a predetermined location on a target plate;
• placing an object to be covered between the-spinneret and the target plate;
• forcing a liquid through said spinneret, thereby transferring at least some of said electric potential to said liquid, such that said liquid forms a stream directed toward said predetermined location on said target plate due to the electric potential between said liquid and said predetermined location, and whereby said stream splays into a plurality of nanofibers due to the electric potential between said liquid and said predetermined location;
• and whereby said plurality of nanofibers collide with said object;
• ensuring said nanofibers are wet enough to adhere to said object when said nanofibers collide with said object;
• placing a material over said object while said nanofibers are still wet, such that said nanofibers bind said material to said object.

A method of bonding a substance to a structure comprising:

• providing an electrospinning apparatus;
• providing a bonding substance in liquid form;
• introducing said bonding substance in liquid form to said electrospinning apparatus;
• operating said electrospinning apparatus such that said bonding substance is splayed into nanofibers having an average diameter of less than 100 micrometers;
• directing said nanofibers to a target structure;
• ensuring said nanofibers remain sufficiently moist as said nanofibers contact said target structure such that said nanofibers form a thin covering on said target structure wherein said covering includes a plurality of randomly located interstitial spaces.

A method of delivering a drug to a target site comprising:

• charging a spinneret with an electric potential relative to a predetermined location on a target plate;
• forcing a liquid containing a drug through said spinneret, thereby transferring at least some of said electric potential to said liquid, such that said liquid forms a stream directed toward said predetermined location on said target plate due to the electric potential between said liquid and said predetermined location, and whereby said stream splays into a plurality of nanofibers due to the electric potential between said liquid and said predetermined location;
• ensuring said nanofibers are wet enough to adhere together when said nanofibers collide with said target plate, to form a cloth-like material;
• placing said cloth-like material at a target site in vivo, thereby allowing tissue at the target site to elute said drug from said cloth-like material.

A method of delivering radiation to a target site comprising:

• charging a spinneret with an electric potential relative to a predetermined location on a target plate;
• forcing a liquid containing an isotope through said spinneret, thereby transferring at least some of said electric potential to said liquid, such that said liquid forms a stream directed toward said predetermined location on said target plate due to the electric potential between said liquid and said predetermined location, and whereby said stream splays into a plurality of nanofibers due to the electric potential between said liquid and said predetermined location;
• positioning said spinneret a predetermined distance from said target plate such that said nanofibers are wet enough to adhere together when said nanofibers collide with said target plate, to form a cloth-like material;
• placing said cloth-like material at a target site in vivo;
• directing electromagnetic energy toward said cloth-like material.

A stent comprising:

• a body lumen support structure;
• a covering disposed on said support structure;
• said covering comprised of a plurality of fibrils having an average diameter less than 100 micrometers;
• said fibrils arranged in a substantially random pattern on said support structure so as to create a plurality of substantially random interstitial spaces within said covering;
• and,
• a therapeutic agent disposed within said covering.

A structure for maintaining the patency of a body lumen comprising:

• a supporting scaffold;
• a covering applied to said scaffold;
• said covering comprising a plurality of nanofibers applied to said scaffold in a substantially wet state so as to maximize adherence of said nanofibers to one another and to said scaffold;
• said nanofibers having an average diameter less than about 100 micrometers;
• a plurality of interstitial spaces in said covering formed by said nanofibers.

A method of maintaining the patency of a body lumen comprising:

• providing a stent frame;
• covering said stent frame with wet fibrils, said fibrils having a diameter less than 100 micrometers in diameter;
• allowing said wet fibrils to adhere to one another and to said stent frame so as to create a covering having a plurality of substantially randomly placed interstitial spaces;
• loading said covering with a therapeutic agent;
• introducing said sent frame into a body lumen;
• allowing said therapeutic agent to affect tissue in said body lumen.

A drug-eluting cloth comprising:

• an inner layer of fibers of a first average diameter and defining interstices between the fibers;
• a therapeutic releasably contained by the inner layer;
• an outer layer of fibers of a second average diameter and defining interstices between said fibers that are smaller than the interstices of the inner layer such that the release rate of the therapeutic is controlled by the interstices of the outer layer;
• wherein the outer layer is operably attached to and substantially encasing the inner layer.