BME 410 Lecture Notes - Lecture 17: Polyacrylamide Gel Electrophoresis, Micropatterning, Soft Lithography

• School: USC
• Department: Biomedical Engineering
• Course: BME 410
• Professor: Megan Mc Cain

Document Summary

Necessary for: models of human development and disease, drug screening. Size scale: need control from cm to nm, computer chips are fabricated in micrometer scale. Stamp is inverted and brought into contact with substrate. The pdms stamp is then peeled away with the ink still on the substrate. Two fabrication steps: photolithography: fabricate silicon wafer template, soft lithography: fabricate pdms stamps. Silicon wafer deposit photoresist add mask uv light exposure; remove mask; dissolve photoresist pour on pdms; cure 65c; peel away pdms. Patterns designed in cad programs and printed onto polyester transparencies (cid:2) (cid:2) (cid:2: high dpi (high resolution, dots per inch, resolution>10um. Low levels of pollutants: room air = 35,000,000 particles/m^3, class 100 cleanroom = 3,500 particles/m^3, class 10 cleanroom = 350 particles/m^3. Silicon wafers: thin slices of semiconductor material, highly pure, crystalline brittle, 1-12 inch diameter, 200-1000um thickness, light-sensitive chemical, positive: exposed photoresist soluble, negative: exposed photoresist insoluble.