**2. Soft lithography materials**

Why soft lithography is called "soft"? One of the reasons is the use of soft organic materials such as polydimethyl siloxane(PDMS), polymethyl methacrylate (PMMA), and polycarbonate (PC). PDMS is most widely used in bioscience research, because it has good

Application of Soft Lithography and Micro-Fabrication on Neurobiology 19

**PDMS stamp** 

**Drip into "ink"** 

**Substrate** 

**Protein Patterns** 

**Printing** 

Fig. 2. Schematics of the processes of μCP

**Dried in a gentle nitrogen stream** 

**Pretreatment with Piranha solution**

**Some Pressure was added** 

biocompatibility, chemical stability, optical transparency, air permeability, elasticity. Moreover, the polymer precursors can be aggregated into a mold by UV radiation. PDMS polymerization is shown in Figure 1.

$$\text{H}\_{\text{H}}\xrightarrow[\text{CH}\_{3}^{2-}]{\text{CH}\_{3}}\text{H}\_{\text{H}}\xrightarrow[\text{CH}\_{3}^{2-}]{}\text{HO}\xrightarrow[\text{CH}\_{3}^{2-}]{\text{CH}\_{3}}\text{H}\_{\text{H}}\text{O}^{+}\text{O}^{-}\text{H}\_{2}\text{O}^{-}\text{O}^{-}$$
