TY  - JOUR
A1  - Pacholski, Claudia
A1  - Rosencrantz, Sophia
A1  - Rosencrantz, Ruben R.
A1  - Balderas-Valadez, Ruth Fabiola
T1  - Plasmonic biosensors fabricated by galvanic displacement reactions for monitoring biomolecular interactions in real time
JF  - Analytical and bioanalytical chemistry : a merger of Fresenius' journal of analytical chemistry, Analusis and Quimica analitica
N2  - Optical sensors are prepared by reduction of gold ions using freshly etched hydride-terminated porous silicon, and their ability to specifically detect binding between protein A/rabbit IgG and asialofetuin/Erythrina cristagalli lectin is studied. The fabrication process is simple, fast, and reproducible, and does not require complicated lab equipment. The resulting nanostructured gold layer on silicon shows an optical response in the visible range based on the excitation of localized surface plasmon resonance. Variations in the refractive index of the surrounding medium result in a color change of the sensor which can be observed by the naked eye. By monitoring the spectral position of the localized surface plasmon resonance using reflectance spectroscopy, a bulk sensitivity of 296 nm +/- 3 nm/RIU is determined. Furthermore, selectivity to target analytes is conferred to the sensor through functionalization of its surface with appropriate capture probes. For this purpose, biomolecules are deposited either by physical adsorption or by covalent coupling. Both strategies are successfully tested, i.e., the optical response of the sensor is dependent on the concentration of respective target analyte in the solution facilitating the determination of equilibrium dissociation constants for protein A/rabbit IgG as well as asialofetuin/Erythrina cristagalli lectin which are in accordance with reported values in literature. These results demonstrate the potential of the developed optical sensor for cost-efficient biosensor applications.
KW  - Optical sensor
KW  - Gold nanostructure
KW  - Localized surface plasmon resonance
KW  - Surface functionalization
KW  - Biomolecular interactions
KW  - Lectin
Y1  - 2020
U6  - https://doi.org/10.1007/s00216-020-02414-0
SN  - 1618-2642
SN  - 1618-2650
VL  - 412
IS  - 14
SP  - 3433
EP  - 3445
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - von Rüsten-Lange, Maik
A1  - Luetzow, Karola
A1  - Neffe, Axel T.
A1  - Lendlein, Andreas
T1  - Characterization of oligo(ethylene glycol) and oligoglycerol functionalized poly(ether imide) by angle-dependent X-ray photoelectron spectroscopy
JF  - Journal of applied biomaterials & functional materials
N2  - Purpose: Previous investigations have shown that poly(ether imide) (PEI) membranes can be functionalized with aminated macromolecules. In this study we explored whether the characterization of PEI functionalized with oligo(ethylene glycol) (OEG) or linear, side chain methylated oligoglycerols (OGMe), by angle-dependent X-ray induced photoelectron spectroscopy (XPS) can be used to prove the functionalization, give insight into the reaction mechanism and reveal the spatial distribution of the grafts.
 Methods: PEI membranes were functionalized under alkaline conditions using an aqueous solution with 2 wt% of alpha-amino-methoxy oligo(ethylene glycol) (M-n = 1,320 g.mol(-1)) or linear, side chain methylated monoamine oligoglycerols (M-n = 1,120, 1,800 or 2,270 g.mol(-1)), respectively. The functionalized membranes were investigated using XPS measurements at different detector angles to enable comparison between the signals related to the bulk and surface volume and were compared with untreated and alkaline-treated PEI membranes.
 Results: While at a perpendicular detector angle the bulk signals of the PEI were prominent, at larger surface volume-related detector angles, the signals for OGMe and OEG were determinable.
 Conclusion: The surface functionalization of PEI with OEG and OGMe could be verified by the angle-dependent XPS. The observations proved the functionalization at the PEI surface, as the polyethers were detected at angles providing signals of the surface volume. Furthermore, the chemical functions determined verified a covalent binding via the nucleophilic addition of the amine functionalized OGMe and OEG to the PEI imide function.
KW  - Poly(ether imide)
KW  - Oligo(ethylene glycol)
KW  - Oligoglycerols
KW  - Angle-dependent X-ray induced photoelectron spectroscopy
KW  - Surface functionalization
Y1  - 2012
U6  - https://doi.org/10.5301/JABFM.2012.10345
SN  - 2280-8000
VL  - 10
IS  - 3
SP  - 215
EP  - 222
PB  - Wichtig
CY  - Milano
ER  -