Reconfigurable Optical Sensor for Metal-Ion-Mediated Label-Free Recognition of Different Biomolecular Targets - Supporting Information

1 Supporting Information Reconfigurable optical sensor for metal-ion mediated label-free recognition of different biomolecular targets Tiziano Di Giulio1, Martina Corsi2, Francesco Gagliani1, Giuseppe De Benedetto3, Cosimino Malitesta1, Aurora Mazzei4, Amilcare Barca5, Tiziano Verri4, Giuseppe Barillaro2*, Elisabetta Mazzotta1* 1Laboratorio di Chimica Analitica, Dipartimento di Scienze e Tecnologie Biologiche e Ambientali (Di.S.Te.B.A.), Università del Salento, via Monteroni 73100 Lecce – Italy 2Dipartimento di Ingegneria dell’Informazione, Università di Pisa, via G. Caruso 16, 56126 Pisa – Italy 3Laboratorio di Spettrometria di Massa Analitica ed Isotopica, Dipartimento di Beni Culturali, Università del Salento, via Monteroni 73100 Lecce – Italy 4Laboratorio di Fisiologia Applicata, Dipartimento di Scienze e Tecnologie Biologiche e Ambientali (Di.S.Te.B.A.), Università del Salento, via Monteroni 73100 Lecce – Italy 5Laboratorio di Fisiologia Applicata, Dipartimento di Medicina Sperimentale (Di.Me.S), Università del Salento, via Monteroni 73100 Lecce – Italy *[email protected]; [email protected] 2 Figure S1. Optical characterization of PSiO2 scaffolds upon GLYMO-IDA silanization. Reflectance spectra recorded in air on a PSiO2 scaffold oxidized at 750 °C for 1 h before and after GLYMO-IDA silanization for different times, namely 30 min, 1 and 2 hours. 800700600500400 0 10 20 30 40 50 PSiO2 30 min silanization 1h silanization 2h silanization Reflectance (%) Wavelength (nm) 3 Figure S2. Optical characterization of GLYMO-IDA functionalized PSiO2 scaffolds after interaction with different metal-ions. Reflectance spectra recorded after GLYMO-IDA functionalized PSiO2 samples exposure to different metal-ion (Cu2+, Zn2+, Ni2+, Fe3+) solutions. 800700600500400 0 10 20 30 40 50 GLYMO-IDA Cu2+ Fe3+ Ni2+ Zn2+ Reflectance (%) Wavelength (nm) 4 Figure S3. X-ray photoelectron spectroscopy of GLYMO-IDA functionalized PSiO2 scaffolds after interaction with different metal-ions. High-definition N 1s spectra of A) GLYMO-IDA, B) Cu2+/GLYMO-IDA, C) Zn2+/GLYMO-IDA, D) Ni2+/GLYMO-IDA, E) Fe3+/GLYMO-IDA. Spectra are fitted and charging corrected. 5 Figure S4. Effect of metal ion concentration on CAR detection. A) Changes in the effective optical thickness (EOT) of PSiO2 scaffolds functionalized with Cu2+ ions at different concentrations ranging from 0.025 to 0.2 M, upon exposure to 1 mM of CAR. EOT0 refers to pure buffer (n=2). B) Effective optical thickness (EOT) measured on a PSiO2 sensor after various functionalization and sensing steps, upon exposure Cu2+ solutions at concentrations from 0.025 to 0.2 M. Specifically, EOT values were measured upon grafting of GLYMO-IDA, Cu2+ chelation, binding of CAR (1 mM), CAR removal by HCl washing, Cu2+ removal in EDTA solution for each Cu2+ concentration tested. 6 Figure S5. X-ray photoelectron spectroscopy characterization of carnosine binding on sensor. High-definition spectra of A) Cu 2p and B) N 1s regions recorded before (red line) and after (blue line) the incubation of the sensor with carnosine. 7 Figure S6. Optical detection of carnosine different concentrations on A) Cu2+/GLYMO-IDA and B) Zn2+/GLYMO-IDA functionalized PSiO2 scaffolds. Reflectance spectra recorded before (red spectrum) and after sensor exposure to increasing carnosine concentrations. 8 Figure S7. Repeatability of the sensor toward CAR detection. Sensor response (calculated as EOT-EOT0) recorded for three different measurements using the same sensor (n=3). 1 2 3 0 5 10 15 20 25 30 35 40 45 EOT - EOT0 (nm) Repeatability 9 Figure S8. Optical characterization of Fe3+/GLYMO-IDA functionalized PSiO2 scaffolds in ATP detection tests. Reflectance spectra recorded after sensor exposure to increasing ATP concentrations. 800700600500400 0 10 20 30 40 50 60 Fe3+ 0.2 mM ATP 0.5 mM ATP 1 mM ATP 2 mM ATP Reflectance (%) Wavelength (nm)