TY - JOUR A1 - Zhao, Shuang A1 - Caruso, Frank A1 - Dähne, Lars A1 - Decher, Gero A1 - De Geest, Bruno G. A1 - Fan, Jinchen A1 - Feliu, Neus A1 - Gogotsi, Yury A1 - Hammond, Paula T. A1 - Hersam, Mark C. A1 - Khademhosseini, Ali A1 - Kotov, Nicholas A1 - Leporatti, Stefano A1 - Li, Yan A1 - Lisdat, Fred A1 - Liz-Marzán, Luis M. A1 - Moya, Sergio A1 - Mulvaney, Paul A1 - Rogach, Andrey L. A1 - Roy, Sathi A1 - Shchukin, Dmitry G. A1 - Skirtach, Andre G. A1 - Stevens, Molly M. A1 - Sukhorukov, Gleb B. A1 - Weiss, Paul S. A1 - Yue, Zhao A1 - Zhu, Dingcheng A1 - Parak, Wolfgang J. T1 - The Future of Layer-by-Layer Assembly: A Tribute to ACS Nano Associate Editor Helmuth Möhwald JF - ACS Nano N2 - Layer-by-layer (LbL) assembly is a widely used tool for engineering materials and coatings. In this Perspective, dedicated to the memory of ACS Nano associate editor Prof. Dr. Helmuth Möhwald, we discuss the developments and applications that are to come in LbL assembly, focusing on coatings, bulk materials, membranes, nanocomposites, and delivery vehicles. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12356 SN - 1936-086X VL - 13 IS - 6 SP - 6151 EP - 6169 ER - TY - JOUR A1 - Zhao, Shuang A1 - Yue, Zhao A1 - Zhu, Dingcheng A1 - Harberts, Jann A1 - Blick, Robert H. A1 - Zierold, Robert A1 - Lisdat, Fred A1 - Parak, Wolfgang J. T1 - Quantum Dot/TiO2 Nanocomposite-Based Photoelectrochemical Sensor for Enhanced H2O2 Detection Applied for Cell Monitoring and Visualization JF - Small N2 - This work exploits the possibility of using CdSe/ZnS quantum dot (QD)-electrodes to monitor the metabolism of living cells based on photoelectrochemical (PEC) measurements. To realize that, the PEC setup is improved with respect to an enhanced photocurrent signal, better stability, and an increased signal-to-noise ratio, but also for a better biocompatibility of the sensor surface on which cells have been grown. To achieve this, a QD-TiO2 heterojunction is introduced with the help of atomic layer deposition (ALD). The heterojunction reduces the charge carrier recombination inside the semiconductor nanoparticles and improves the drift behavior. The PEC performance is carefully analyzed by adjusting the TiO2 thickness and combining this strategy with multilayer immobilizations of QDs. The optimal thickness of this coating is ≈5 nm; here, photocurrent generation can be enhanced significantly (e.g., for a single QD layer electrode by more than one order of magnitude at 0 V vs Ag/AgCl). The resulting optimized electrode is used for hydrogen peroxide (H2O2) sensing with a good sensitivity down to µmolar concentrations, reusability, stability, response rate, and repeatability. Finally, the sensing system is applied to monitor the activity of cells directly grown on top of the electrode surface. KW - biocompatible interface with atomic layer deposition KW - biosensor KW - detection of cellular metabolism KW - light addressable potentiometric sensor KW - photocurrent measurements Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-19642 VL - 20 IS - 45 PB - Wiley ER - TY - JOUR A1 - Zhao, Shuang A1 - Riedel, Marc A1 - Patarroyo, Javier A1 - Bastús, Neus G. A1 - Puntes, Victor A1 - Yue, Zhao A1 - Lisdat, Fred A1 - Parak, Wolfgang J. T1 - Tailoring of the photocatalytic activity of CeO₂ nanoparticles by the presence of plasmonic Ag nanoparticles JF - Nanoscale N2 - The present study investigates basic features of a photoelectrochemical system based on CeO2 nanoparticles fixed on gold electrodes. Since photocurrent generation is limited to the absorption range of the CeO2 in the UV range, the combination with metal nanoparticles has been studied. It can be shown that the combination of silver nanoparticles with the CeO2 can shift the excitation range into the visible light wavelength range. Here a close contact between both components has been found to be essential and thus, hybrid CeO2@Ag nanoparticles have been prepared and analyzed. We have collected arguments that electron transfer occurs between both compositional elements of the hybrid nanoparticles.The photocurrent generation can be rationalized on the basis of an energy diagram underlying the necessity of surface plasmon excitation in the metal nanoparticles, which is also supported by wavelength-dependent photocurrent measurements. However, electrochemical reactions seem to occur at the CeO2 surface and consequently, the catalytic properties of this material can be exploited as exemplified with the photoelectrochemical reduction of hydrogen peroxide. It can be further demonstrated that the layer-by layer technique can be exploited to create a multilayer system on top of a gold electrode which allows the adjustment of the sensitivity of the photoelectrochemical system. Thus, with a 5-layer electrode with hybrid CeO2@Ag nanoparticles submicromolar hydrogen peroxide concentrations can be detected. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-16361 VL - 14 SP - 12048 EP - 12059 PB - Royal Society of Chemistry (RSC) ER - TY - JOUR A1 - Munchel, Sarah A1 - Hoang, Yen A1 - Yue, Zhao A1 - Cottrell, Joseph A1 - Klotzle, Brandy A1 - Godwin, Andrew K. A1 - Koestler, Devin A1 - Beyerlein, Peter A1 - Fan, Jian-Bing A1 - Bibikova, Marina A1 - Chien, Jeremy T1 - Targeted or whole genome sequencing of formalin fixed tissue samples: potential applications in cancer genomics JF - Oncotarget N2 - Current genomic studies are limited by the poor availability of fresh-frozen tissue samples. Although formalin-fixed diagnostic samples are in abundance, they are seldom used in current genomic studies because of the concern of formalin-fixation artifacts. Better characterization of these artifacts will allow the use of archived clinical specimens in translational and clinical research studies. To provide a systematic analysis of formalin-fixation artifacts on Illumina sequencing, we generated 26 DNA sequencing data sets from 13 pairs of matched formalin-fixed paraffin-embedded (FFPE) and fresh-frozen (FF) tissue samples. The results indicate high rate of concordant calls between matched FF/FFPE pairs at reference and variant positions in three commonly used sequencing approaches (whole genome, whole exome, and targeted exon sequencing). Global mismatch rates and C·G > T·A substitutions were comparable between matched FF/FFPE samples, and discordant rates were low (<0.26%) in all samples. Finally, low-pass whole genome sequencing produces similar pattern of copy number alterations between FF/FFPE pairs. The results from our studies suggest the potential use of diagnostic FFPE samples for cancer genomic studies to characterize and catalog variations in cancer genomes. KW - cancer genomics KW - FFPE DNA KW - whole exome sequencing KW - whole genome sequencing KW - copy number alteration Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-6307 SN - 1949-2553 VL - 6 IS - 28 SP - 25943 EP - 25961 ER - TY - GEN A1 - Schubert, Kirsten A1 - Khalid, Waqas A1 - Yue, Zhao A1 - Parak, Wolfgang J. A1 - Lisdat, Fred T1 - Halbleiternanopartikel-modifizierte Elektrode zum Nachweis von Substraten von NADH-abhängigen Enzymreaktionen T2 - Wissenschaftliche Beiträge 2009/2010 N2 - Es wurde ein Elektrodensystem entwickelt, das aufbauend auf Halbleiternanopartikeln (so genannte Quantenpunkte) die sensitive Detektion des Enzymkofaktors NADH (nicotinamide adenine dinucleotide) erlaubt. Kolloidale halbleitende CdSe/ZnS-Nanokristalle sind durch ein Dithiol über Chemisorption an Gold gebunden. Das Stromsignal kann durch die Beleuchtung der Quantenpunkt modifizierten Oberfläche beeinflusst werden. Durch Photoanregung entstehen Elektron-Loch- Paare in den Nanopartikeln, die als anodischer oder kathodischer Photostrom detektiert werden können. Die Immobilisierung der Nanokristalle ist durch amperometrische Photostrom- und Quarzmikrowaage-Messungen (quartz crystal microbalance) verifiziert. Diese Studie zeigt, dass CdSe/ZnS-Quantenpunktmodifizierte Elektroden eine konzentrationsabhängige NADH-Detektion im Bereich von 20μM bis 2mM bei relativ niedrigem Potential (um 0V vs Ag/AgCl, 1 M KCl) ermöglichen. Somit können solche Elektroden in Kombination mit NADH-produzierenden Reaktionen für die lichtgesteuerte Analyse der entsprechenden Substrate des Biokatalysators genutzt werden. Es wird gezeigt, dass mit einem solchen Elektrodensystem und Photostrommessungen ein Glukosenachweis möglich ist. N2 - An electrode system based on semiconductive nanoparticles (so called quantum dots) was developed which allows the sensitive detection of the enzyme cofactor NADH (nicotinamide adenine dinucleotide). Colloidal semiconductive CdSe/ZnS nanocrystals are bound to gold via a dithiol compound by chemisorption. The current signal can be influenced by illumination of the quantum dot-modified electrode surface. Because of photoexcitation electron-holepairs are generated in the nanoparticles which can be detected as anodic or cathodic photocurrent. The immobilisation of the nanocrystals is verified by photocurrent and quarz crystal microbalance (QCM) measurements. This study shows that CdSe/ZnS-quatum dot-modified electrodes provide a concentration-dependent detection of NADH in the range of 20μM up to 2mM at relatively low overpotentials (around 0V vs Ag/ AgCl, 1 M KCl). Such electrodes can be used in combination with NADH-producing reactions for the lighttriggered analysis of the corresponding substrate of the biocatalyst. The detection of glucose with such an electrode system and photocurrent measurements is shown. Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus-810 SN - 0949-8214 VL - 14 SP - 13 EP - 22 ER -