A versatile approach for achieving metal ion mediated interactions on porous silicon interferometers

Di.S.Te.B.A. (DIPARTIMENTO di SCIENZE e TECNOLOGIE BIOLOGICHE e AMBIENTALI) Tiziano Di Giulio, Francesco Gagliani, Martina Corsi, Cosimino Malitesta, Giuseppe Barillaro, Elisabetta Mazzotta A VERSATILE APPROACH FOR ACHIEVING METAL ION MEDIATED INTERACTIONS ON POROUS SILICON INTERFEROMETERS XXX Congresso della Divisione di Chimica Analitica della Società Chimica Italiana (SCI) A new frontier in sensor development: reconfigurabity for a wider application -For multiple target detection, it is necessary to develop multiple sensors or at least multiple molecular recognition elements; -one sensor for one target Tiziano Di Giulio A VERSATILE APPROACH FOR ACHIEVING METAL ION MEDIATED INTERACTIONS ON POROUS SILICON INTERFEROMETERS One reconfigurable sensor to detect different targets or even groups of molecules Classical approach: sensor design on the basis of the target to detect (in general, one for time) Emerging approach: tunability of the receptor or the transducer system to increase sensor applicabilty, in term of sensitivity or multi-target detection with the same sensor. The proposal: development of a reconfigurable sensor using: Porous silicon (PSiO2), as interferometer Adaptive artificial receptor taking advantage of metal-ion mediated interaction A new frontier in sensor development: reconfigurabity for a wider application Emerging approach: tunability of the receptor or the transducer system to increase sensor applicabilty, in term of sensitivity or multi-target detection with the same sensor. Classical approach: sensor design on the basis of the target to detect (in general, one for time) Thickness: 4m Porous diameter: 50 nm Porosity: 75% Optical sensing based on porous silicon (PSiO2) as interferometer Tiziano Di Giulio A VERSATILE APPROACH FOR ACHIEVING METAL ION MEDIATED INTERACTIONS ON POROUS SILICON INTERFEROMETERS light reflecte d light FFT Signal modification is produced by: A) insertion/grafting; B) removal or C) adsorption of compounds on porous silicon layer A B C A B C m=2nd/λm EOT (effective optical thickness): 2nL PSiO2 interferometers functionalization A)grafting of the artificial receptor B)Target binding C)sensor reconfiguration target molecule Another metal ion Tiziano Di Giulio A VERSATILE APPROACH FOR ACHIEVING METAL ION MEDIATED INTERACTIONS ON POROUS SILICON INTERFEROMETERS Versatility in receptor configuration UV-VIS spectroscopy characterization X-ray photoelectron spectroscopy (XPS) characterization Refrative index PSiO2: ~1.3 RIU (refractive index unit); Cu: 0.26-1.15 RIU Zn: 0.8-1.1 RIU Fe: 1.9-3 RIU Ni: 1.5-2.1 RIU Different metal ions (Cu2+, Zn2+, Fe3+, Ni2+) were anchored on the surface of porous layer (PSiO2) - Carnosine plays several homeostatic roles in human excitable tissues; - Anti-Aggregating Effect on Aβ1-42 Fibril Formation; - Pathological conditions (carnosinemia) - Abundant in muscle and nerve tissues (up to 1-5 mM);Carnosine dipeptide Carnosine detection tests Tiziano Di Giulio A VERSATILE APPROACH FOR ACHIEVING METAL ION MEDIATED INTERACTIONS ON POROUS SILICON INTERFEROMETERS Carnosine dipeptide Repeatability Stability Carnosine detection tests Tiziano Di Giulio A VERSATILE APPROACH FOR ACHIEVING METAL ION MEDIATED INTERACTIONS ON POROUS SILICON INTERFEROMETERS Sensor exposure to histidine related compounds (HRC) carnosine 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 carnosine carnosine/anserine (1:1) carnosine/anserine (1:0.1) carnosine/glycyl-l-proline (1:1) carnosine/glycyl-l-proline (1:0.1) carnosine/histidine (1:1) carnosine/histidine (1:0.1) carnosine/b-alanine (1:1) carnosine/b-alanine (1:0.1) (EOT-EOT0)/EOTC molar ratio anserine -alanine glycyl-l-proline l-histidine 0 10 20 30 40 50 100 500 1000 EOT-EOT0 (nm) concentration (M) carnosine anserine glycil-l-proline L-histidine b-alanine Tiziano Di Giulio A VERSATILE APPROACH FOR ACHIEVING METAL ION MEDIATED INTERACTIONS ON POROUS SILICON INTERFEROMETERS