Microfluidics projects overview

low-cost and open source microfluidic chip for DNA synthesis and probably DNA sequencing, thermocycling, cell culture, transgenics/electroporation, bubble logic, etc.

Strategy

probably 2-layer PDMS with pressure valves

Equipment

  • mini laser cutter (1 micron beam width, approx. 1 micron step size)
  • dust fan for cutting fumes
  • syringe pumps
  • spin coater

Testing

Microfluidics are often tested by flowing dyes and fluorescent beads.

  • anionic (- charge)
  • cationic (+ charge)

Food Coloring

Name Characteristics Image of molecule
Tartrazine (FD&C Yellow 5) anionic. hydrophilic azo dye, maximum absorbance in an aqueous solution at 425 nm. Yellow 5
Indigo carmine (FD&C Blue 2) anionic. pH indicator, Indolesulfonic acid, Indigo carmine in a 0.2% aqueous solution is blue at pH 11.4 and yellow at 13.0. Indigo carmine is also a redox indicator, turning yellow upon reduction. Blue 2
Fast Green FCF (FD&C Green 3) mixed cat/anionic. It is used as a quantitative stain for histones at alkaline pH after acid extraction of DNA. It is also used as a protein stain in electrophoresis. Its absorption maximum is at 625 nm. Green 3
Erythrosine (FD&C Red 3) anionic. It is the disodium salt of 2,4,5,7-tetraiodofluorescein. Its maximum absorbance is at 530 nm in an aqueous solution, and it is subject to photodegradation. Red 3
Brilliant Blue FCF (FD&C Blue 1) mixed, looks mostly anionic. It is soluble in water, and the solution has a maximum absorption at about 628 nanometers. Blue 1
Allura Red AC (FD&C Red 40) anionic. in solution, its maximum absorbance lies at about 504 nm. Red 40
Sunset Yellow (FD&C Yellow 6) anionic. pH dependent azo dye with a maximum absorption at about 480 nm at pH 1 and 443 nm at pH 13 with a shoulder at 500 nm. Yellow 6

Common Biotech Dyes

Name Characteristics Image of molecule
Crystal Violet cationic? When dissolved in water, the dye has a blue-violet colour with an absorbance maximum at 590 nm and an extinction coefficient of 87,000 M−1 cm−1. The colour of the dye depends on the acidity of the solution. At a pH of 1.0, the dye is green with absorption maxima at 420 nm and 620 nm, while in a strongly acidic solution (pH of −1), the dye is yellow with an absorption maximum at 420 nm. Crystal Violet