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Human astrocytes. Scale bar = 50 μm. (A,C) Astrocytes in astrocyte medium before measurement. (B) Astrocytes from (A) after 2 h in 0.01 M PBS (pH 7.4) at room temperature. (D) Astrocytes from (C) after the 6.5 h biosensor array measurement in GFDMEM in a humidified incubator at37 °C and 5% CO 2 . Note that astrocytes in PBS for 2 h have lost their processes, which corresponds to losing adherence, whereas astrocytes in GFDMEM look the same after 6.5 h.
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Simultaneous measurements of glucose, lactate, and neurotransmitters (e.g., glutamate) in cell culture over hours and days can provide a more dynamic and longitudinal perspective on ways neural cells respond to various drugs and environmental cues. Compared with conventional microfabrication techniques, direct writing of conductive ink is cheaper,...
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... PBS is an optimal electrolyte for the biosensors, it is poorly suited for maintaining human astrocytes long-term. Within only 2 h of being in PBS at room temperature, the morphology of human astrocytes changes drastically (Fig. 3A,B). Rivera et al. found that although human astrocytes in PBS for 2 h is viable, 38 they had largely lost their processes and adherence to the culture plate. Magnesium and calcium ions are needed for cells to adhere to substrate after incubation with serum proteins or cellular products. 40 Even using Dulbecco's PBS, which contains these ...
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... we decided to measure lactate, glutamate, and glucose from astrocytes in cell culture medium. Astrocyte medium contains 5.5 mM glucose, so we used glucose-free DMEM + 2% FBS + 100 U/mL penicillin/streptomycin (GFDMEM). In contrast to astrocytes in PBS (Fig. 3A,B), astrocytes in GFDMEM in a humidified incubator at 37 °C and 5% CO 2 maintain the same morphology after a 6.5 h measurement (Fig. ...
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... and glucose from astrocytes in cell culture medium. Astrocyte medium contains 5.5 mM glucose, so we used glucose-free DMEM + 2% FBS + 100 U/mL penicillin/streptomycin (GFDMEM). In contrast to astrocytes in PBS (Fig. 3A,B), astrocytes in GFDMEM in a humidified incubator at 37 °C and 5% CO 2 maintain the same morphology after a 6.5 h measurement (Fig. ...
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... glutamate, and glucose measurements between 1 and 2 h. It is possible that our measurements overestimate glucose and glutamate consumption and underestimate lactate secretion since enzymatic biosensor sensitivities are expected to decrease over time during continuous measurement. We tested the lactate sensor's response after measurement (Suppl. Fig. ...
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... 0.01 M PBS (pH 7.4). (A) Representative plot of current as a function of time during a simultaneous calibration of lactate, glutamate, and glucose sensors on a biosensor array in GFDMEM in a humidified incubator at 37 °C and 5% CO 2 . Biosensors in GFDMEM were calibrated at fewer points than in PBS. (B) Comparison of biosensor sensitivity in PBS (Fig. 3) to sensitivity in GFDMEM. The error bars correspond to standard deviations (n = 3). *p < 0.05, **p < 0.001. Lactate, glucose, and glutamate as a function of time 1 mm above human astrocyte culture in GFDMEM ina humidified incubator at 37 °C and 5% CO 2 . Note that the glucose response is significantly larger due to the larger glucose ...
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... This array allows for the concurrent measurement of glucose, lactate, and neurotransmitters like glutamate in cell cultures over hours to days. 88 Notably, the application of this array offers a dynamic and longitudinal view on how neural cells respond to various drugs and environmental cues. It can be seamlessly integrated into micro-fluidic organon-a-chip platforms or as part of intelligent culture dish systems. ...
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... Glass micropipettes are fragile and necessitate positional feedback to avoid physical contact with the substrate. To avoid this limitation, an electrohydrodynamic (EHD) dispensing technique introduced electrostatic attractions between the ink and the substrate to create a meniscus at the Ref. 109 Ref. 111 Ref. 121 Ref. 118 Ref. 119 Ref. 76 Ref. 79 Ref. 211 Ref. 125 Ref. 153 Ref. 86 Ref. 87 Ref. 77 Ref. 46 Ref. 150 Ref. 58 Viscosity (Pa s -1 ) ...
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