TY  - JOUR
A1  - Fandrich, Artur
A1  - Buller, Jens
A1  - Memczak, Henry
A1  - Stoecklein, W.
A1  - Hinrichs, K.
A1  - Wischerhoff, E.
A1  - Schulz, B.
A1  - Laschewsky, André
A1  - Lisdat, Fred
T1  - Responsive Polymer-Electrode Interface-Study of its Thermo- and pH-Sensitivity and the Influence of Peptide Coupling
JF  - Electrochimica acta : the journal of the International Society of Electrochemistry (ISE)
N2  - This study introduces a thermally responsive, polymer-based electrode system. The key component is a surface-attached, temperature-responsive poly(oligoethylene glycol) methacrylate (poly(OEGMA)) type polymer bearing photoreactive benzophenone and carboxy groups containing side chains. The responsive behavior of the polymer in aqueous media has been investigated by turbidimetry measurements. Polymer films are formed on gold substrates by means of the photoreactive 2(dicyclohexylphosphino)benzophenone (DPBP) through photocrosslinking. The electrochemical behavior of the resulting polymer-substrate interface has been investigated in buffered [Fe(CN)6](3-)/[Fe (CN)6](4-)solutions at room temperature and under temperature variation by cyclic voltammetry (CV). The CV experiments show that with increasing temperature structural changes of the polymer layer occur, which alter the output of the electrochemical measurement. Repeated heating/cooling cycles analyzed by CV measurements and pH changes analyzed by quartz crystal microbalance with dissipation monitoring (QCM-D) reveal the reversible nature of the restructuring process. The immobilized films are further modified by covalent coupling of two small biomolecules - a hydrophobic peptide and a more hydrophilic one. These attached components influence the hydrophobicity of the layer in a different way the resulting change of the temperature-caused behavior has been studied by CV indicating a different state of the polymer after coupling of the hydrophobic peptide.
KW  - Stimuli-responsive materials
KW  - electroanalysis
KW  - modified electrode
KW  - bioreceptors
KW  - peptides
KW  - surface modification
KW  - cyclic voltammetry
KW  - IR ellipsometry
KW  - quartz crystal microbalance
Y1  - 2017
U6  - https://doi.org/10.1016/j.electacta.2017.01.080
SN  - 0013-4686
SN  - 1873-3859
VL  - 229
SP  - 325
EP  - 333
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Riedel, M.
A1  - Sabir, N.
A1  - Scheller, Frieder W.
A1  - Parak, Wolfgang J.
A1  - Lisdat, Fred
T1  - Connecting quantum dots with enzymes
BT  - mediator-based approaches for the light-directed read-out of glucose and fructose oxidation
JF  - Nanoscale
N2  - The combination of the biocatalytic features of enzymes with the unique physical properties of nanoparticles in a biohybrid system provides a promising approach for the development of advanced bioelectrocatalytic devices. This study describes the construction of photoelectrochemical signal chains based on CdSe/ZnS quantum dot (QD) modified gold electrodes as light switchable elements, and low molecular weight redox molecules for the combination with different biocatalysts. Photoelectrochemical and photoluminescence experiments verify that electron transfer can be achieved between the redox molecules hexacyanoferrate and ferrocene, and the QDs under illumination. Since for both redox mediators a concentration dependent photocurrent change has been found, light switchable enzymatic signal chains are built up with fructose dehydrogenase (FDH) and pyrroloquinoline quinone-dependent glucose dehydrogenase ((PQQ) GDH) for the detection of sugars. After immobilization of the enzymes at the QD electrode the biocatalytic oxidation of the substrates can be followed by conversion of the redox mediator in solution and subsequent detection at the QD electrode. Furthermore, (PQQ) GDH has been assembled together with ferrocenecarboxylic acid on top of the QD electrode for the construction of a funtional biohybrid architecture, showing that electron transfer can be realized from the enzyme over the redox mediator to the QDs and subsequently to the electrode in a completely immobilized fashion. The results obtained here do not only provide the basis for light-switchable biosensing and bioelectrocatalytic applications, but may also open the way for self-driven point-of-care systems by combination with solar cell approaches (power generation at the QD electrode by enzymatic substrate consumption).
Y1  - 2017
U6  - https://doi.org/10.1039/c7nr00091j
SN  - 2040-3364
SN  - 2040-3372
VL  - 9
SP  - 2814
EP  - 2823
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -