TY  - JOUR
A1  - Vogel, Patrick
A1  - Rückert, Martin Andreas
A1  - Friedrich, Bernhard
A1  - Tietze, Rainer
A1  - Lyer, Stefan
A1  - Kampf, Thomas
A1  - Hennig, Thomas
A1  - Dölken, Lars
A1  - Alexiou, Christoph
A1  - Behr, Volker Christian
T1  - Critical Offset Magnetic PArticle SpectroScopy for rapid and highly sensitive medical point-of-care diagnostics
JF  - Nature Communications
N2  - Magnetic nanoparticles (MNPs) have been adapted for many applications, e.g., bioassays for the detection of biomarkers such as antibodies, by controlled engineering of specific surface properties. Specific measurement of such binding states is of high interest but currently limited to highly sensitive techniques such as ELISA or flow cytometry, which are relatively inflexible, difficult to handle, expensive and time-consuming. Here we report a method named COMPASS (Critical-Offset-Magnetic-Particle-SpectroScopy), which is based on a critical offset magnetic field, enabling sensitive detection to minimal changes in mobility of MNP ensembles, e.g., resulting from SARS-CoV-2 antibodies binding to the S antigen on the surface of functionalized MNPs. With a sensitivity of 0.33 fmole/50 µl (≙7 pM) for SARS-CoV-2-S1 antibodies, measured with a low-cost portable COMPASS device, the proposed technique is competitive with respect to sensitivity while providing flexibility, robustness, and a measurement time of seconds per sample. In addition, initial results with blood serum demonstrate high specificity.
KW  - biochemical assays
KW  - characterization and analytical techniques
KW  - magnetic properties and materials
KW  - nanoparticles
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300893
VL  - 13
ER  - 
TY  - JOUR
A1  - Ryma, Matthias
A1  - Genç, Hatice
A1  - Nadernezhad, Ali
A1  - Paulus, Ilona
A1  - Schneidereit, Dominik
A1  - Friedrich, Oliver
A1  - Andelovic, Kristina
A1  - Lyer, Stefan
A1  - Alexiou, Christoph
A1  - Cicha, Iwona
A1  - Groll, Jürgen
T1  - A Print-and-Fuse Strategy for Sacrificial Filaments Enables Biomimetically Structured Perfusable Microvascular Networks with Functional Endothelium Inside 3D Hydrogels
JF  - Advanced Materials
N2  - A facile and flexible approach for the integration of biomimetically branched microvasculature within bulk hydrogels is presented. For this, sacrificial scaffolds of thermoresponsive poly(2-cyclopropyl-2-oxazoline) (PcycloPrOx) are created using melt electrowriting (MEW) in an optimized and predictable way and subsequently placed into a customized bioreactor system, which is then filled with a hydrogel precursor solution. The aqueous environment above the lower critical solution temperature (LCST) of PcycloPrOx at 25 °C swells the polymer without dissolving it, resulting in fusion of filaments that are deposited onto each other (print-and-fuse approach). Accordingly, an adequate printing pathway design results in generating physiological-like branchings and channel volumes that approximate Murray's law in the geometrical ratio between parent and daughter vessels. After gel formation, a temperature decrease below the LCST produces interconnected microchannels with distinct inlet and outlet regions. Initial placement of the sacrificial scaffolds in the bioreactors in a pre-defined manner directly yields perfusable structures via leakage-free fluid connections in a reproducible one-step procedure. Using this approach, rapid formation of a tight and biologically functional endothelial layer, as assessed not only through fluorescent dye diffusion, but also by tumor necrosis factor alpha (TNF-α) stimulation, is obtained within three days.
KW  - hydrogels
KW  - microvasculature
KW  - melt electrowriting
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318532
VL  - 34
IS  - 28
ER  -