Packaging with active protection layer
An implantable medical device including a plurality of components on a substrate, and a biocompatible multi-layer coating applied at least in part by vapor deposition to conform to and sealingly cover at least a portion of the components and/or the substrate. The coating is applied in at least two sets of layers, wherein each set has at least one layer formed by dissociation of a polymeric precursor and then deposition of that precursor, and another layer is a biocompatible liquid.
1. An implantable medical device comprising:
a plurality of components on a substrate; and
a biocompatible multi-layer coating applied at least in part by vapour deposition to conform to and sealingly cover at least a portion of the components and the substrate, the coating being applied in at least two sets of layers, wherein each set has at least one layer formed by dissociation of a polymeric precursor and then deposition of that dissociated precursor, and another layer is a biocompatible liquid, and further wherein each of the sets has at least three layers, and diffusion through each layer differs from that of the other layers in the set.
2. The implantable medical device of claim 1 wherein each layer differs in at least one diffusion barrier property from the other layer in the set.
3. The implantable medical device of claim 1 wherein diffusion through each layer differs from that of the other layer in the set and adds to the overall barrier effect of the coating.
4. The implantable medical device of claim 1 wherein the precursor for at least one set is selected from di-p-xylylene and halogenated derivatives thereof.
5. The implantable medical device of claim 4 wherein the precursor is dichloro-p-xylylene.
6. The implantable medical device of claim 1 wherein at least one of the layers enhances wetability of the layer beneath it.
7. The implantable medical device of claim 6 wherein the wetability-enhancing layer includes at least one of chemical and plasma activation of the layer beneath it.
8. The implantable medical device of claim 1 wherein the liquid is applied by condensation.
9. The implantable medical device of claim 1 wherein the liquid is applied as a fog or a mist.
10. The implantable medical device of claim 1 wherein the liquid is applied by dipping or casting.
11. The implantable medical device of claim 1 wherein at least one of the layers in each set is a plasma-enhanced parylene polymer.
12. The implantable medical device of claim 1 wherein at least one liquid layer includes an active agent.
13. The implantable medical device of claim 1 wherein the plurality of components have at least a first three-dimensional portion, and the coating conforms to and sealingly covers at least the first portion of the components.
14. The implantable medical device of claim 13 wherein the multi-layer coating conforms to and sealingly covers at least substantially all of the components.
15. The implantable medical device of claim 1 wherein a barrier property for the transport of impurities is dominated more by the interface between adjacent layers than by the thickness of each individual layer.
16. An implantable medical device comprising:
a plurality of components on a substrate having at least a first three-dimensional portion; and
a biocompatible multi-layer coating applied at least in part by vapour deposition to conform to and sealingly cover at least the first portion of the components and the substrate, the coating being applied in at least two sets of layers, wherein each set has at least one layer formed by dissociation of a polymeric precursor and then deposition of that dissociated precursor, and another layer is a biocompatible liquid, and wherein a barrier property for the transport of impurities is dominated more by the interface between adjacent layers than by the thickness of each individual layer, and further wherein each of the sets has at least three layers, and diffusion through each layer differs from that of the other layers in the set.
17. The implantable medical device of claim 16 wherein the multi-layer coating conforms to and sealingly covers at least substantially all of the components and the substrate.