Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

The Utility Of The Nitric Oxide Electrochemical Sensor In Biomedical Research

2,498 views

Published on

Journal Club 1 :The Utility Of The Nitric Oxide Electrochemical Sensor In Biomedical Research

Published in: Technology, Business
  • Be the first to comment

The Utility Of The Nitric Oxide Electrochemical Sensor In Biomedical Research

  1. 1. <ul><ul><li>Review paper : Nitric Oxide Electrochemical Sensor in Biomedical Research </li></ul></ul>
  2. 2. OUT LINE <ul><li>Nitric Oxide </li></ul><ul><li>Electrochemical Sensor </li></ul><ul><li>Principles of Detection </li></ul><ul><li>Commercial </li></ul>
  3. 3. Nitric Oxide <ul><li>Nitric oxide or Nitrogen monoxide is a chemical compound with chemical formula NO. This gas is an important signaling molecule in the body of mammals </li></ul>
  4. 4. NITRIC OXIDE Molecular formula : NO Molar mass : 30.0061 Appearance : colourless gas Shape : Linear Melting point : −163.6°C Boiling point : −151.7°C The nitric oxide molecule is a free radical , high reactivity NO is a fundamental player in the fields of neuroscience, physiology, and immunology, and was proclaimed “Molecule of the Year” in 1992
  5. 5. NITRIC OXIDE <ul><li>NO is messenger molecule involved in many physiological processes </li></ul><ul><li>Levels of NO production are important in protecting an organ such as the liver from ischemic damage. </li></ul><ul><li>Levels of NO production result in direct tissue toxicity to the vascular collapse associated with septic shock. </li></ul><ul><li>Chronic expression of NO is associated with various carcinomas and inflammatory conditions including juvenile diabetes, multiple sclerosis, arthritis and ulcerative colitis. </li></ul>
  6. 6. Technical applications <ul><li>Although NO has relatively few direct uses, it is produced on a massive scale as an intermediate in the Ostwald process for the synthesis of nitric acid from ammonia. In 2005, the US alone produced 6M metric tons of nitric acid </li></ul>4NH 3 (g) + 5O 2 (g) -> 4NO(g) + 6H 2 O(g) 2NO(g) + O 2 (g) -> 2NO 2 (g) 3NO 2 (g) + H 2 O(l) -> 2HNO 3 (aq) + NO(g) 4NO 2 (g) + O 2 (g) + 2H 2 O(l) -> 4HNO 3 (aq)
  7. 7. Biological functions <ul><li>NO is signaling molecules in biological processes </li></ul><ul><li>Nitric oxide, known as the 'endothelium-derived relaxing factor', or 'EDRF' , is biosynthesised endogenously from arginine and oxygen by various nitric oxide synthase (NOS) enzymes </li></ul>
  8. 8. Biological functions <ul><li>NO is signaling molecules in biological processes </li></ul><ul><li>Nitric oxide, known as the 'endothelium-derived relaxing factor', or 'EDRF' , is biosynthesised endogenously from arginine and oxygen by various nitric oxide synthase (NOS) enzymes </li></ul>
  9. 9. Endothelium-derived relaxing factor(EDRF) <ul><li>Figure 1 . L-arginine - nitric oxide system. B 2 , bradykinin B 2 receptor; cGMP, cyclic guanosine 3',5'-monophosphate; eNOS, endothelial nitric oxide synthase; GC, guanylate cyclase; GTP, guanosine 5'-triphosphate; M, muscarinic receptor; NO, nitric oxide; .OH, hydroxyl radical; ONOO - , peroxynitrite. </li></ul>
  10. 10. The Nobel Prize in Physiology or Medicine 1998 <ul><li>Robert F Furchgott Louis J Ignarro Ferid Murad </li></ul><ul><li>Discoveries concerning &quot;the nitric oxide as a signalling molecule in the cardiovascular system&quot;. </li></ul><ul><li>Effects include blood vessel dilatation, neurotransmission modulation of the hair cycle , and penile erections . Nitroglycerin and amyl nitrite serve as vasodilators because they are converted to nitric oxide in the body </li></ul><ul><li>Popularly known by the trade name Viagra </li></ul>
  11. 11. Immune response <ul><li>Nitric oxide is also generated by macrophages and neutrophils as part of the human immune response. </li></ul><ul><li>Nitric oxide is toxic to bacteria and other human pathogens . </li></ul>
  12. 12. Reactions <ul><li>When exposed to oxygen, NO is converted into nitrogen dioxide . 2NO + O 2 -> 2NO 2 </li></ul><ul><li>NO react with oxygen and water to form HNO2 or nitrous acid . 4 NO + O 2 + 2 H 2 O -> 4 HNO 2 </li></ul>
  13. 13. Preparation <ul><li>nitric oxide is produced industrially by the direct reaction of O 2 and N2 at high temperatures. </li></ul><ul><li>In the laboratory, it is conveniently generated by reduction of nitric acid : 8HNO 3 + 3Cu -> 3Cu(NO 3 )2 + 4H2O + 2NO </li></ul><ul><li>or by the reduction of nitrous acid : 2 NaNO 2 + 2 NaI + 2 H 2 SO 4 -> I 2 + 4 NaHSO 4 + 2 NO 2 NaNO 2 + 2 FeSO 4 + 3 H2SO 4 -> Fe2(SO4) 3 + 2 NaHSO 4 + 2 H 2 O + 2 NO 3 KNO 2 (l) + KNO 3 (l) + Cr 2 O 3 (s) -> 2 K 2 CrO 4 (s) + 4 NO (g) </li></ul>
  14. 14. Some of the methods commonly used for the determination of NO include <ul><li>Chemiluminescence </li></ul><ul><li>Electron paramagnetic </li></ul><ul><li>Resonance (EPR) spectrometry </li></ul><ul><li>The Griess method </li></ul><ul><li>Spectrophotometric assays </li></ul><ul><ul><li>They can not be used for continuous monitoring </li></ul></ul><ul><ul><li>or local measurement of NO concentrations in </li></ul></ul><ul><ul><li>real time. </li></ul></ul>
  15. 15. Electrochemical techniques i = nFCAke -(E-E0)(- α nF/RT)
  16. 16. NO-electrochemical microsensors <ul><li>Structure </li></ul><ul><ul><li>Printed Screen </li></ul></ul><ul><ul><li>Nedle </li></ul></ul><ul><li>Electrode </li></ul><ul><ul><li>Carbon fiber </li></ul></ul><ul><ul><li>Pt </li></ul></ul><ul><ul><li>Glassy Carbon </li></ul></ul><ul><ul><li>Gold </li></ul></ul>
  17. 17. NO-electrochemical microsensors <ul><li>Modifier(s) Layer </li></ul><ul><ul><li>Nafion </li></ul></ul><ul><ul><li>Cellulose </li></ul></ul><ul><ul><li>O-PD </li></ul></ul><ul><ul><li>NiTHMP </li></ul></ul><ul><ul><li>NiTMPyP </li></ul></ul><ul><ul><li>Neoprene </li></ul></ul><ul><ul><li>CytC-PITO </li></ul></ul><ul><ul><li>PolyCoTAPc </li></ul></ul><ul><ul><li>etc.. </li></ul></ul>
  18. 20. Problematic interfering <ul><li>Nitrite </li></ul><ul><li>ascorbate </li></ul><ul><li>dopamine </li></ul>
  19. 21. Nafion®
  20. 22. NO-electrochemical microsensors <ul><li>Detection limit 0.5 nM </li></ul><ul><li>Carbon (fiber; o=30-40μm;length=200-250 μm) </li></ul><ul><li>NiTHMP1/Nafion3/AAO4/polylysine4 </li></ul><ul><li>0.65V /Ag;AgCl </li></ul><ul><li>(aerated PBS, pH=7.4) </li></ul>
  21. 23. Activator for WPI nitric oxide sensors <ul><li>NSA SPECIFICATIONS </li></ul><ul><li>Battery 1.5 V AAA </li></ul><ul><li>Applied Potential 860 mV </li></ul><ul><li>Battery Useful Life One year </li></ul><ul><li>1 mM </li></ul>

×