Protein Extraction from Human Tear Using Schirmer Strip

Begin by cutting and discarding the front end of the Schirmer strip containing the dried human tears beyond the zero millimeter mark. Then cut the strip into one millimeter intervals and place the pieces in a 1.5 milliliter micro centrifuge tube. Next, add 100 microliters of lysis buffer to the micro centrifuge tube.

Vortex it at 1000 RPM at room temperature for one hour in a thermo mixer. After brief centrifugation, transfer the supernatant to a new 1.5 milliliter micro centrifuge tube. Using clean forceps, move the strips into 200 microliter pipette tips.

Place the tips back into the same micro centrifuge tube, then centrifuge it for maximum sample recovery. Measure the protein concentration using bicinchoninic acid or a compatible protein assay.