Tham khảo tài liệu 'biosensors for health environment and biosecurity part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 447 Electrochemical Biosensors to Monitor Extracellular Glutamate and Acetylcholine Concentration in Brain Tissue and respectively. The total voltage scale corresponds to a generated current of 20 nA for Glu and 30 nA for Ach calibrations corresponding to 50 nA V. These results show that biosensors are adequate for their use in vivo conditions. Fig. 1. Calibration curves for Glu A and Ach B . With respect to the speed of neurotransmitters measurement with these biosensors time resolution was evaluated as the beginning of the response in each concentration until they reached a maximum value this time was approximately of 20 seconds. 3. Animal studies These biosensors can be used under anesthesia or in awake animals as shown here. For Glu biosensors were implanted into the cerebral cortex of rat pups at three postnatal day under anesthesia in a three electrodes arrangement working reference and counter in order to accomplish an electrochemical cell in situ. Every biosensor must be calibrated before its use. Once the animal is recovered from anesthesia the terminal of each electrode is connected to the potentiostat through a socket connector and after of an equilibration period to reach a baseline the animal is ready to monitor the Glu extracellular concentration into the brain in any experimental condition. In the example showed here the effect of subcutaneous monosodium glutamate administration in neonate rast 5mg Kg of body weigh was initially tested resulting in a rise in extracelluar Glu concentration Fig. 2A this Glu elevation lasted approximately 20 minutes. In previous work it has been demonstrated that in immature brain the blood brain barrier is not completely developed Cernak 2010 besides the high Glu concentration used is enough to disrupt the barrier due to an osmotic effect similar effect has been found with the use of 448 Biosensors for Health Environment and Biosecurity manitol Rapoport 2000 . Additionally in our previous work it was showed that .
