['PDMS', '(', 'Polydimethylsiloxane', ')', 'has', 'become', 'by', 'far', 'the', 'most', 'popular', 'material', 'in', 'the', 'academic', 'microfluidics', 'community', 'because', 'it', 'is', 'inexpensive', ',', 'easy', 'to', 'fabricate', 'by', 'replication', 'of', 'molds', 'made', 'using', 'rapid', 'prototyping', 'or', 'other', 'techniques', ',', 'flexible', ',', 'optically', 'transparent', ',', 'biocompatible', 'and', 'its', 'fabrication', 'does', 'not', 'require', 'high', 'capital', 'investment', 'and', 'cleanroom', 'conditions', '.']