Guidewires with lubricious surface and method of their production
First Claim
1. A guidewire for insertion of tubular instruments into a body, which comprises:
- (a) a core element having sufficient rigidity to be inserted into a body;
(b) an outside tubular layer about said core element, forming an elastomeric hydrogel sleeve, said sleeve having;
(i) a chemical composition gradient with increasing concentration of polar groups in the outward direction away from said core element;
(ii) a swelling gradient represented by increasing water content volumetrically in the outward direction away from said core element; and
,(iii) compression stress decreasing the swelling at least in the outer most layer below its equilibrium value.
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Accused Products
Abstract
The present invention guidewire involves an elongated, non-hydrogel core element forming an inner part of the device, and an integral outside tubular layer of elastomeric hydrogel ("hydrogel sleeve"). This outer hydrogel layer has unique physical characteristics. They are (a) Gradient of chemical composition with increasing concentration of polar groups in the outward direction away from the core element; (b) Gradient of swelling in contact with water with water content increasing in the outward direction away from the core element; (c) Compressive stress in the outer hydrophilic layer causing the hydrogel in that layer to swell to a water content lower than its equilibrium value in a free-swelling state; and, optionally, (d) Inward-directed radial stress pushing the outside hydrogel layer constantly against the inner core element. The present invention also involves the methods of making these guidewires, including melt extrusion directly onto the core element, coagulation from solution, in situ hydrogel polymer formation, and tubing extrusion followed by consequent shrink-fit over the core.
207 Citations
31 Claims
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1. A guidewire for insertion of tubular instruments into a body, which comprises:
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(a) a core element having sufficient rigidity to be inserted into a body; (b) an outside tubular layer about said core element, forming an elastomeric hydrogel sleeve, said sleeve having; (i) a chemical composition gradient with increasing concentration of polar groups in the outward direction away from said core element; (ii) a swelling gradient represented by increasing water content volumetrically in the outward direction away from said core element; and
,(iii) compression stress decreasing the swelling at least in the outer most layer below its equilibrium value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of making a guidewire for insertion of tubular instruments into a body, which comprises:
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(a) by conventional methods, forming a core element having sufficient ridigity to be inserted into a body, from one or more materials selected from the group consisting of metal, plastic, carbon, glass and ceramics; (b) forming an outside tubular layer about said core as an elastomeric hydrogel sleeve, and controlling the formation of the elastomeric hydrogel sleeve to create; (i) a chemical composition gradient with increasing concentration of polar groups in the outward direction away from said core element; and
,(ii) a swelling gradient represented by increasing water content volumetrically in the outward direction away from said core element. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification