Silver nanoplate compositions and methods
Embodiments of the present invention relate to methods for preparing high optical density solutions of nanoplates, such as silver nanoplates or silver platelet nanoparticles, and to nanoparticles, solutions and substrates prepared by said methods. The process can include the addition of stabilizing agents (e.g., chemical or biological agents bound or otherwise linked to the nanoparticle surface) that stabilize the nanoparticle before, during, and/or after concentration, thereby allowing for the production of a stable, high optical density solution of silver nanoplates. The process can also include increasing the concentration of silver nanoplates within the solution, and thus increasing the solution optical density.
1. A process for increasing an optical density of a solution of stable, silver nanoplates to preserve shape post-concentration, comprising:
providing a solution comprising silver nanoplates having a plate shape, an extinction spectra, and a first peak optical density between 0.1-10 cm −1 ;
adding a concentration stabilizing chemical agent to the solution of silver nanoplates;
adding borate to the solution of silver nanoplates; and
increasing the concentration of silver nanoplates in the solution to generate a concentrated solution using tangential flow filtration, thereby increasing the optical density of the concentrated solution to a second peak optical density greater than 10 cm −1 ,
wherein the silver nanoplates in the concentrated solution retain the plate shape and the extinction spectra at the second peak optical density greater than 10 cm −1 .
2. The process of claim 1 , wherein the stabilizing agent comprises at least one of the group consisting of polyvinyl pyrollidone, polyvinyl alcohol, polyethylene glycol, and dextran.
3. The process of claim 1 , wherein the stabilizing agent comprises at least one of the group consisting of polysulphonates, ethylene oxides, phenols, and carbohydrates.
4. The process of claim 1 , wherein the concentration stabilizing chemical agent is a water soluble polymer.
5. The process of claim 1 , wherein the concentration stabilizing chemical agent is a metal or metalloid oxide.
6. The process of claim 5 , wherein the stabilizing chemical agent is a silicon dioxide shell.
7. The process of claim 6 , wherein the silicon dioxide shell ranges in thickness from 1 nm to 100 nm.
8. The process of claim 5 , wherein the stabilizing chemical agent is a titanium dioxide shell.
9. The process of claim 1 , wherein a combination of stabilizing agents are used.
10. The process of claim 1 , further comprising adding any of the group selected from an acid, a base, and a buffering agent to the solution.
11. The process of claim 1 , wherein the silver nanoplates have an aspect ratio of between 1.5 and 25.
12. The process of claim 1 , wherein the silver nanoplates have an edge length between 10 nm and 250 nm.
13. The process of claim 1 , further providing the solution of silver nanoplates with a seed mediated growth method.
14. The process of claim 1 , wherein the concentrated solution of silver nanoplates is washed with between 1 and 5 wash volumes after increasing the concentration using tangential flow filtration.
15. The process of claim 1 , where the solution of silver nanoplates is incubated with a substrate.
16. A process for increasing an optical density of a solution of stable silver nanoplates to preserve shape post-concentration, comprising:
providing a solution comprising silver nanoplates having a plate shape,
wherein the solution has an extinction spectra and a first peak optical density between 0.1-10 cm −1 ;
adding a polyvinyl containing polymer and borate to the solution; and
increasing the concentration of silver nanoplates in the solution to generate a concentrated solution, thereby increasing the optical density of the concentrated solution to a second peak optical density greater than 10 cm −1 ,
wherein the silver nanoplates in the concentrated solution retain the plate shape and the extinction spectra at the second peak optical density greater than 10 cm −1 .
17. The process of claim 16 , wherein silver nanoplates have an individual edge length between 10 nm and 250 nm and an aspect ratio of between 1.5 and 25, and wherein the polyvinyl containing polymer comprises any one or more of the group consisting of: a polyvinyl alcohol and polyvinyl pyrrolidone.
18. The process of claim 16 , further comprising adding any one or more of the group consisting of: an acid, a base, and a buffering agent to the solution.
19. The process of claim 16 , further comprising providing via seed mediated growth the silver nanoplates with an aspect ratio of between 1.5 and 25 and associating the solution with a substrate.
20. The process of claim 16 , further comprising associating the silver nanoplates with skin.