Plasmonic micropillar array with embedded nanoparticles for large area cell force sensing
In various embodiments a plasmonic cell force sensor platform is provided where the platform comprises a plurality of micropillars, where micropillars comprising the plurality of micropillars each have a nanoparticle (e.g., a plasmonic nanoparticle, a fluorescent nanoparticle, etc.) disposed at the tip.
1. A method of fabricating a cell force sensor platform comprising a plurality of micropillars, wherein micropillars comprising said plurality of micropillars each have a single plasmonic nanoparticle disposed at the tip, said method comprising:
preparing an array of wells that form a negative mold for a micropillar array;
depositing a metal nanofilm over said negative mold wherein said metal nanofilm comprises the metal that will form the nanoparticles;
removing the metal on the mold surface leaving metal microdisks in the bottom of the wells of said negative mold;
filling the negative mold with a polymer that is to form the micropillars; and
melting the microdisks which transfer onto the tips of the micropillars formed by said polymer; and
removing the micropillar array from the negative mold.
2. The method of claim 1 , wherein preparing an array of wells comprises casting said negative mold using a soft lithography polymer on a positive master mold.
3. The method of claim 2 , wherein said soft lithography polymer is PDMS.
4. The method of claim 2 , wherein said master mold is formed by etching a silicon substrate.
5. The method claim 1 , wherein said depositing a metal nanofilm comprises depositing comprises depositing one or more layers of metal comprising a metal selected from the group consisting of ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, copper, titanium, tungsten or an alloy, oxide, or nitride thereof.
6. The method of claim 1 , wherein said depositing a metal nanofilm comprises depositing a multi-layer metal nanofilm.
7. The method of claim 6 , wherein said multilayer metal nanofilm is an SiO2/Ti/Au multilayer nanofilm.
8. The method of claim 1 , wherein said removing comprises using tape to remove metal on the mold surface.
9. The method of claim 1 , wherein said melting is by irradiation with laser pulses.
10. The method of claim 9 , wherein said melting is by irradiation with nanosecond laser pulses.