Nanostructured materials have proven as one of the most powerful tool in new technologies and research, due to their absolutely peculiar properties at nanometer size scale. Many studies have shown that optical, mechanical, photo-catalytic and transport properties drastically changes, depending on quantum size effect, as the mean diameter of the particles is in the exciton size regime (i.e. 10nm) [1-9 and ref. therein]. As a matter of fact, metallic and semiconductor nanosized materials have found large applications in biochemistry as well as photocatalysis, optoelectronics, photochemistry and bioanalytical techniques. Nanoparticles have been also designed in biosensing for many purposes, such as: - to enhance the electronic transfer mechanism in electroanalytical detectors; - to increase the device sensitivity, i.e. reducing the background ratio; - to modify the electrode supports in order to tailor the biomolecules immobilization process, for multi enzymatic sensor arrays or in poly-analytes detection systems. The concept of self assembled monolayers (SAMs) has been thus extended to the surface activation by organic monolayers, chemico-physical modification, or nanosized metal insertion onto several surfaces. Due to its special characteristic of easily forming SAM through thio-derivative compounds, gold electrode has been mainly used as the transducer in electrochemical biosensors. For our purposes, nanowires of gold were synthesized according to electroless deposition methods into a polycarbonate membrane with controlled pore size, obtaining nanoelectrode ensembles (NEEs) with special electrochemical features [10-11]. NEEs were deposited on the working probe and coupled with carbon screen printed electrode (SPE) to give a novel easy to be used tool for disposable biosensors, which has been defined as nanoelectrode ensemble on screen printed substrate (NEE/SPS). Features of NEE/SPS sensors and biosensors were electrochemically compared to unmodified carbon or gold SPEs using immobilized glucose oxidase as biochemical model system. Sequential deposition of SAMs and polyelectrolyte onto NEE/SPS has been experimented to extend the potential range of applicability for third generation biosensors where direct electron transfer between protein and working electrode is achieved. REFERENCES 1. M. Nirmal, D.J. Norris, M. Kuno, M.G. Bawendi, A.L. Efros, M. Rosen, Phys. Rev. Lett., 75 (1995) 3728-3731. 2. L. Manna, E.C. Scher, A.P. Alivisatos, Journal of Cluster Science, 13 n. 4 (2002) 521. 3. A.P. Alivisatos, Science, 271 (1996) 933. 4. C.M. Lieber, Solid State Commun., 107 (1998) 607. 5. V. Albe, C. Jouanin, D. Bertho, J. Cryst. Growth, 185 (1998) 388. 6. R.E. Smalley, B.I. Yakobson, Solid State Commun., 107 (1998) 597. 7. A.J. Williamson, A. Zunger, Phys. Rev. B-Condens Matter, 59 (1999) 15819. 8. M. Bruchez, M. Moronne, P. Gin, S. Weiss, A.P. Alivisatos, Science, 281 (1998) 2013. 9. A.P. Alivisatos, J. Phys. Chem., 100 (1996) 13226- 13239. 10. B. Brunetti, P. Ugo, L.M. Moretto, C.R. Martin, J. Electroanalytical Chemistry, 491 (2000) 166 11. L.M. Moretto, N. Pepe, P. Ugo, Talanta, 62 (2003) 1055.
Coupling Smart Molecules into Chips
2006
Abstract
Nanostructured materials have proven as one of the most powerful tool in new technologies and research, due to their absolutely peculiar properties at nanometer size scale. Many studies have shown that optical, mechanical, photo-catalytic and transport properties drastically changes, depending on quantum size effect, as the mean diameter of the particles is in the exciton size regime (i.e. 10nm) [1-9 and ref. therein]. As a matter of fact, metallic and semiconductor nanosized materials have found large applications in biochemistry as well as photocatalysis, optoelectronics, photochemistry and bioanalytical techniques. Nanoparticles have been also designed in biosensing for many purposes, such as: - to enhance the electronic transfer mechanism in electroanalytical detectors; - to increase the device sensitivity, i.e. reducing the background ratio; - to modify the electrode supports in order to tailor the biomolecules immobilization process, for multi enzymatic sensor arrays or in poly-analytes detection systems. The concept of self assembled monolayers (SAMs) has been thus extended to the surface activation by organic monolayers, chemico-physical modification, or nanosized metal insertion onto several surfaces. Due to its special characteristic of easily forming SAM through thio-derivative compounds, gold electrode has been mainly used as the transducer in electrochemical biosensors. For our purposes, nanowires of gold were synthesized according to electroless deposition methods into a polycarbonate membrane with controlled pore size, obtaining nanoelectrode ensembles (NEEs) with special electrochemical features [10-11]. NEEs were deposited on the working probe and coupled with carbon screen printed electrode (SPE) to give a novel easy to be used tool for disposable biosensors, which has been defined as nanoelectrode ensemble on screen printed substrate (NEE/SPS). Features of NEE/SPS sensors and biosensors were electrochemically compared to unmodified carbon or gold SPEs using immobilized glucose oxidase as biochemical model system. Sequential deposition of SAMs and polyelectrolyte onto NEE/SPS has been experimented to extend the potential range of applicability for third generation biosensors where direct electron transfer between protein and working electrode is achieved. REFERENCES 1. M. Nirmal, D.J. Norris, M. Kuno, M.G. Bawendi, A.L. Efros, M. Rosen, Phys. Rev. Lett., 75 (1995) 3728-3731. 2. L. Manna, E.C. Scher, A.P. Alivisatos, Journal of Cluster Science, 13 n. 4 (2002) 521. 3. A.P. Alivisatos, Science, 271 (1996) 933. 4. C.M. Lieber, Solid State Commun., 107 (1998) 607. 5. V. Albe, C. Jouanin, D. Bertho, J. Cryst. Growth, 185 (1998) 388. 6. R.E. Smalley, B.I. Yakobson, Solid State Commun., 107 (1998) 597. 7. A.J. Williamson, A. Zunger, Phys. Rev. B-Condens Matter, 59 (1999) 15819. 8. M. Bruchez, M. Moronne, P. Gin, S. Weiss, A.P. Alivisatos, Science, 281 (1998) 2013. 9. A.P. Alivisatos, J. Phys. Chem., 100 (1996) 13226- 13239. 10. B. Brunetti, P. Ugo, L.M. Moretto, C.R. Martin, J. Electroanalytical Chemistry, 491 (2000) 166 11. L.M. Moretto, N. Pepe, P. Ugo, Talanta, 62 (2003) 1055.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
