Silk-based piezoelectric materials

Patent metadata

Field	Value
Publication number	US-9761789-B2
Application number	US-201113876472-A
Country	US
Kind code	B2
Filing date	Sep 27, 2011
Priority date	Sep 27, 2010
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

The invention relates to methods and compositions for preparing silk-based piezoelectric materials and methods for increasing piezoelectricity in silk matrices.

First claim

What is claimed is:

1. A silk-based piezoelectric material comprising:
a silk fibroin matrix characterized by uniaxially aligned silk II crystals,
wherein the silk-based piezoelectric material is characterized in that when it is exposed to a perturbation, the material exhibits piezoelectricity having an absolute shear piezoelectricity coefficient of at least about 1.5 pC/N.

2. The silk-based piezoelectric material of claim 1 , wherein the material is characterized in that it exhibits at least one of the following parameters:
(a) oscillatory behavior between about 1 kHz and about 500 MHz;
(b) a Mohs hardness value of about 7, a Vickers indentation hardness of about 1181 kg/mm 2 , or a Rosival grinding hardness value of about 100;
(c) a Young's modulus of about 100 GPa;
(d) a Q factor between about 104 and about 107; or
(e) a draw ratio of at least about 2.

3. The silk-based piezoelectric material of claim 1 , wherein the perturbation is an applied electric field and the material is characterized in that it exhibits piezoelectricity.

4. The silk-based piezoelectric material of claim 3 , wherein the piezoelectricity comprises an oscillation, vibration, pressure, force, acceleration, strain, sound, or a combination thereof.

5. The silk-based piezoelectric material of claim 1 , wherein the perturbation is or comprises voltage, power, mechanical stress, strain, sound, or a combination thereof.

6. The silk-based piezoelectric material of claim 5 , wherein the mechanical stress is or comprises pressure, acceleration, temperature, or force.

7. A cardiac assistance device, comprising the silk-based piezoelectric material of claim 1 ,
wherein the piezoelectric material responds to a mechanical force transmitted from heart tissue, and
wherein the response is a source of charge, voltage, and/or current.

8. The cardiac assistance device of claim 7 , wherein the cardiac assistance device is a pacemaker.

9. A method of producing the silk-based piezoelectric material of claim 1 , comprising steps of:
providing a silk fibroin matrix; and
elongating the silk fibroin matrix so as to form a silk-based piezoelectric material having an absolute shear piezoelectricity coefficient of at least about 1.5 pC/N.

10. The method of claim 9 , wherein the elongating step comprises elongating the silk fibroin matrix along an axis of oscillation.

11. The method of claim 9 , wherein the elongating step comprises elongating the silk fibroin matrix so as to form a silk-based piezoelectric material exhibiting one or more of the following parameters:
a) oscillatory behavior between about 1 kHz and about 500 MHz;
b) a Mohs hardness value of about 7, a Vickers indentation hardness of about 1181 kg/mm 2 , or a Rosival grinding hardness value of about 100;
c) a Young's modulus of about 100 GPa;
d) a Q factor between about 104 and about 107;
e) a draw ratio of at least about 2.

12. The method of claim 9 , wherein elongating the silk matrix further comprises:
elongating the silk matrix at a rate of about 0.5 mm/min to about 50 mm/min.

13. The method of claim 9 , further comprising:
heating at least a portion of the silk fibroin matrix to at least a glass transition temperature of the silk fibroin matrix.

14. The method of claim 9 , further comprising:
contacting the silk fibroin matrix with a solvent wherein the solvent is an aqueous solvent, an organic solvent, or combination thereof.

15. A method comprising steps of:
providing the silk-based piezoelectric material of claim 1 , comprising uniaxially aligned, silk II crystals;
applying perturbation to the silk-based piezoelectric material so as to produce piezoelectricity.

16. The method of claim 15 , wherein the perturbation is or comprises voltage, power, mechanical stress, sound, or any combinations thereof.

17. The method of claim 15 , wherein the piezoelectricity comprises oscillation of the silk-based piezoelectric material.

18. The method of claim 15 , further comprising detecting the piezoelectricity.

19. The method of claim 18 , wherein the piezoelectric response comprises oscillation, vibration, pressure, force, acceleration, strain, sound, or a combination thereof.

20. A device comprising a charge, voltage, and/or current source, wherein the source is or comprises the silk-based piezoelectric material of claim 1 .

21. The device of claim 20 , wherein the silk-based piezoelectric material comprises an agent.

22. The device of claim 21 , wherein the agent is selected from a group consisting of: proteins, peptides, nucleic acids, nucleic acid analogs, nucleotides, oligonucleotides, peptide nucleic acids (PNA), aptamers, antibodies or fragments or portions thereof, antigens or epitopes, hormones, hormone antagonists, growth factors or recombinant growth factors and fragments and variants thereof, cell attachment mediators, cytokines, enzymes, drugs, dyes, amino acids, vitamins, antioxidants, antibiotics or antimicrobial compounds, anti-inflammation agents, antifungals, viruses, antivirals, toxins, prodrugs, chemotherapeutic agents, hemostatic agents, pathogens, metabolites, cells, or combinations thereof.

23. The device of claim 20 , wherein the piezoelectricity exhibited by the material is energy, and the energy is harvested by the device.

24. The device of claim 23 , wherein the harvested energy is stored by the device.

25. The device of claim 20 , wherein the device is a sensor, an energy-capturing device, an energy-storing device, a cardiac assistance device, an actuator, or a combination thereof.

26. The device of claim 20 , further comprising a capsule, wherein the device is housed in the capsule.

27. The silk-based piezoelectric material of claim 26 , wherein when exposed to perturbations, the material exhibits piezoelectricity within the capsule that is detected external to the capsule.

28. The silk-based piezoelectric material of claim 27 , wherein the capsule comprises contacts.

29. The silk-based piezoelectric material of claim 28 , wherein the contacts are conductive so that when physically connected to the material the capsule communicates with a power source, a dynamic mechanical analyzer (DMA), an electrometer, and/or combinations thereof.

30. A method comprising steps of:
providing the device of claim 20 ,
implanting the device into a subject;
applying a perturbation so that piezoelectricity is produced in vivo.

31. The method of claim 30 , further comprising a step of harvesting energy generated from the piezoelectricity.

32. The method of claim 31 , further comprising storing the energy.

Assignees

• Omenetto Fiorenzo
• Kaplan David
• Yucel Tuna
• Univ Tufts

Inventors

• Omenetto Fiorenzo
• Kaplan David
• Yucel Tuna

Classifications

• H10P95/00

  Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass · CPC title

• H01L41/45

  Electricity · mapped topic

• H02N2/18

  producing electrical output from mechanical input, e.g. generators (for measurement devices G01) · CPC title

• A61N1/36578

  controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone · CPC title

• A61N1/3785

  generated by biological activity or substance, e.g. body movement · CPC title