TY - JOUR A1 - Meyerhofer, F. A1 - Dissinger, F. A1 - Weigert, Florian A1 - Jungclaus, J. A1 - Müller-Caspary, K. A1 - Waldvogel, S. R. A1 - Resch-Genger, Ute A1 - Voss, T. T1 - Citric Acid Based Carbon Dots with Amine Type Stabilizers: pHSpecific N2 - We report the synthesis and spectroscopic characteristics of two different sets of carbon dots (CDs) formed by hydrothermal reaction between citric acid and polyethylenimine (PEI) or 2,3-diaminopyridine (DAP). Although the formation of amide-based species and the presence of citrazinic acid type derivates assumed to be responsible for a blue emission is confirmed for both CDs by elemental analysis, infrared spectroscopy, and mass spectrometry, a higher abundance of sp2-hybridized nitrogen is observed for DAP-based CDs, which causes a red-shift of the n-π* absorption band relative to the one of PEI-based CDs. These CD Systems possess high photoluminescence quantum yields (QY) of ∼40% and ∼48% at neutral pH, demonstrating a possible tuning of the optical properties by the amine precursor. pH-Dependent spectroscopic studies revealed a drop in QY to < 9% (pH ∼ 1) and < 21% (pH ∼ 12) for both types of CDs under acidic and basic conditions. In contrast, significant differences in the pHdependency of the n-π* transitions are found for both CD types which are ascribed to different (de)protonation sequences of the CD-specific fluorophores and functional groups using Zeta potential analysis. KW - Fluorescence KW - Particle KW - Nano KW - Surface group analysis KW - Carbon dot KW - C-dot KW - Fluorescent probe KW - Quantum yield KW - Synthesis KW - IR KW - MS KW - Polymer KW - Ligand PY - 2020 DO - https://doi.org/10.1021/acs.jpcc.9b11732 VL - 124 IS - 16 SP - 8894 EP - 8904 PB - American Chemical Society AN - OPUS4-50813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - Development of multimodal methods to quantify the total and accessible number of functional groups and ligands on nanomaterials N2 - Engineered and tailored nanomaterials (NM) are of great interest in the life and material sciences, as they can be used, e.g., as drug carriers, barcodes, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. Their performance and safety depend not only on their particle size, size distribution, and morphology, but also on their surface chemistry, i.e., the total number of surface functional groups (FG) and the number of FG accessible for subsequent functionalization with ligands or biomolecules, which in turn determines surface charge, colloidal stability, biocompatibility, and toxicity. It also underlines the importance of validated analytical methods that provide accurate information on these application-relevant physicochemical properties with a known uncertainty. In the case of FG quantification, this calls for robust, fast, inexpensive, and reliable methods which allow for the characterization of a broad variety of NM differing in size, chemical composition, and optical properties. Methods Aiming at the development of simple, versatile, and multimodal tools for the quantification of bioanalytically relevant FG such as amine, carboxy, thiol, and aldehyde functionalities, we investigated and compared various analytical methods commonly used for FG quantification. This includes electrochemical titration methods, dye-based optical assays, and other instrumental analytical techniques such as nuclear magnetic resonance (NMR), mass spectrometry (MS), and thermal analysis methods. Results Here, we will present examples for different types of NMs and FGs including results from a currently running interlaboratory comparison (ILC) with the National Research Council of Canada (NRC) to pave the road for method standardization. Innovative aspects • Surface analysis • Performance and safety of nanomaterials • Standardization T2 - ANAKON 2023 CY - Vienna, Austria DA - 11.04.2023 KW - Engineered Nanomaterials KW - Surface group analysis KW - Optical spectroscopy KW - Quantitative NMR KW - Ligands KW - Dye KW - Particle synthesis KW - Optical Assays KW - Titration KW - Safe-by-Design KW - Nano KW - Nanosafety KW - Silica- and Polystyrene Particles PY - 2023 AN - OPUS4-59127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Design and Quantitative Characterization of Functional Molecular Chromophores and Nanomaterials with UV/vis/NIR/IR Emission – An Overview of Research Activities in Division Biophotonics N2 - In the focus of division Biophotonics are the design, preparation, analytical and spectroscopic characterization, and application of molecular and nanoscale functional materials, particularly materials with a photoluminescence in the visible, near infrared (NIR) and short-wave infrared (SWIR). This includes optical reporters for bioimaging and sensing, security and authentication barcodes, and materials for solid state lighting, energy conversion, and photovoltaics. For the identification of optimum particle structures quantitative spectroscopic studies are performed under application-relevant conditions, focusing on the key performance parameter photoluminescence quantum yield. In addition, simple, cost-efficient, and standardizable strategies for quantifying functional groups on the surface of nano- and microparticles are developed, here with a focus on optical assays and electrochemical titration methods, cross-validated by more advanced methods such as quantitative NMR. In addition, reference materials and reference products are developed for optical methods, particularly luminescence techniques, and for analytical methods utilized for the characterization of nanomaterials. T2 - Projekttreffen Nile-Chrome 2.0 CY - Mainz, Germany DA - 11.12.2023 KW - Fluorescence KW - Quantum yield KW - Optical spectroscopy KW - Reference material KW - Reference data KW - Quality assurance KW - Dye KW - Reference product KW - NIR KW - SWIR KW - Nano KW - Particle KW - Silica KW - Polymer KW - Surface group analysis KW - Sensor molecules PY - 2023 AN - OPUS4-59123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - A Multimodal Approach to Quantify Surface Functional Groups and Ligands on Amorphous Silica Nanoparticles N2 - Nowadays amorphous silica nanoparticles (SiO2-NP) are one of the most abundant engineered nanomaterials, that are highly stable and can be easily produced on a large scale at low cost. Surface functionalized SiO2-NP are of great interest in the life and material sciences, as they can be used e.g. as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. Their performance in such applications depends not only on particle size, size distribution, and morphology, but also on surface chemistry, i.e. the total number of surface functional groups (FG) and the number of FG accessible for subsequent functionalization with ligands or biomolecules, which in turn determines surface charge, colloidal stability, biocompatibility, and toxicity. Aiming at the development of simple, versatile, and multimodal tools for the quantification of many bioanalytically relevant FG and ligands, we investigated and compared various analytical methods commonly used for FG quantification. This includes electrochemical titration methods, dye-based optical assays, and other instrumental analytical techniques such as nuclear magnetic resonance and thermal analysis methods. The potential of our multimodal approach for FG quantification was demonstrated for commercial and custom-made silica particles of varying FG, showing not only an influence of the synthesis methods on the number of FG but also on the performance. In the future, our strategy can contribute to establish multi-method characterization strategies to provide a more detailed picture of the structure-properties relationship. T2 - Advanced Materials Safety 2023 CY - Saarbrücken, Germany DA - 08.11.2023 KW - Amorphous silica particles KW - Surface group analysis KW - Ligands KW - Reference material KW - Optical spectroscopy KW - Quantitative NMR KW - Optical assays KW - Titration KW - Engineered nanomaterials KW - Advanced Materials PY - 2023 AN - OPUS4-59124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella T1 - Multivalent presentation of phenylpropenic acid amide inspired ligands by various nanoparticles and their potential use in anti-inflammatory therapy N2 - Over the years, inflammation has become one of the most rapidly developing areas in medical research, due to new studies indicating its important role in chronical diseases, thrombosis and cancer. A promising target for anti-inflammatory therapy are the multistep adhesion process of leukocytes from the blood vessels into the inflamed tissue. and the numerous involved receptors and ligands. In particular, selectins and their respective carbohydrate ligands can inhibit this key step of the inflammation cascade. In previous work, it was shown that the multivalent presentation of highly negatively charged sulfated and carboxylated ligands on the particle surface can mimic natural selectin binders and increase the inhibition significantly. Recent studies of the antioxidant and health promoting properties of cocoa, dark chocolate and red clover indicating potential anti-inflammatory properties of their clovamide-type phenylpropenoic acid amides, which are able to inhibit p-selectin expression and platelet-leukocyte interactions. Following the idea of small-molecule targeting drugs, we selected different epitopes and immobilized their sulfated derivatives onto different types nanoparticles, followed by a screening of their performance. T2 - SALSA Make and Measure 2024: Interfaces CY - Berlin, Germany DA - 11.09.2024 KW - Gold colloids KW - Surface group analysis KW - Method KW - Quantification KW - Screening KW - Nano KW - Particle KW - Synthesis KW - Quality assurance KW - Surface ligands PY - 2024 AN - OPUS4-62159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -