**3.5 PDMS Lab-on-a-Chip**

PDMS (polydimethylsiloxane) is a straightforward, adaptable, and low-cost polymer that can be used to fabricate LoC by the softlithography. Research laboratories commonly use PDMS for LoC prototyping, which is one of the least resource demanding fabricating methods. PDMS is also broadly utilized on the grounds that it is simple and shabby to create PDMS LoCs [36]. Moreover, LoC made of PDMS takes preferred standpoint of the simple mix of shudder miniaturized scale valves for quick stream switch and penetrability of air for cell-and-tissue-culture-LoCs [37]. Commonly utilized for LoCs prototyping, PDMS demonstrates extreme impediments for modern generation. The properties of PDMS are surprisingly close to that could be obtained from glass and plastic. The cross-linking of many of these polymer chains makes a structure that is flexible and reversibly deformable. **Table 4** summarizes the physical properties of PDMS, and **Table 5** compares polymer and glass as substrate for chemical and biomedical applications [36]. Many of properties demonstrate that the PDMS is very desirable for fabricating microfluidic LoCs.
