1. HPTS- Optical pH Sensor pH sensitive fluorescent dye Absorbance / Excitation changes with pH Emission at 520 nm Excitation Ratiometric

2. pH SENSOR ASSEMBLY FOR OPTICAL CHEMICAL SENSOR White microfiltration membrane backing PEG-dye copolymer hydrogel Transfer adhesive Note: All Optical Chemical Sensors Are Based on Same Concept as pH Sensor

3. pH Sensor Calibration in Cell Suspension

4. E.coli Shake Flask Fermentation with pH Coaster and Sensor Patch Conditions: LB Media, T=37°C, 300 rpm Discrepancy at 6 hrs+ likely due to CO 2

5. Measurement of pCO 2 Important metabolite Critical in bacterial and mammalian cell cultures Conventional technology uses pH probe inside bicarbonate buffer- cumbersome New optical alternative

6. APPLICATION OF OPTICAL CHEMICAL CO 2 SENSOR IN FERMENTATION: E. COLI OD CO 2

7. DISSOLVED OXYGEN OPTICAL- CHEMICAL SENSOR CONSTRUCTION

9. On-line turbidity measurement in E.coli fermentation