Figure 7.

Luciferin/luciferase bioluminescence assay confirms the presence of ATP in a 0.8 mg/mL collagen hydrogel after stimuli addition. Similar to the electrochemical recordings, the incorporation of glutamate induces the most substantial ATP response when compared with other stimuli (purple bar). The cells respond similarly when Ca²⁺ and ionomycin are added (red and orange bars, respectively). Treatment with the intracellular chelator, BAPTA-AM significantly reduces ATP signal when incubated for 1.5 hr to the collagen-containing astrocytes (pink bar) and stimulated with Ca²⁺. The negative demonstrates that no ATP is released when no stimulus is added to a 0.7 X10⁵ cell/mL density (black bar). All luminescence results were acquired and averaged n=3.