TY  - JOUR
AB  - Monitoring electrical activity across multiple planes in 3D cell cultures and organoids is imperative to comprehensively understand their functional connections and behavior. However, traditional planar microelectrode arrays (MEAs) are intended for surface recordings and are inadequate in addressing this aspect. The limitations, such as longer production times and limited adaptability imposed by standard clean-room techniques, constrain the design possibilities for 3D electrode arrays and potentially hinder effective cell-electrode coupling. To tackle this challenge, a novel approach is presented that leverages rapid prototyping processes and additive manufacturing in combination with wet etching and electrodeposition to enhance electrode fabrication and performance. The laser-patterned MEAs on glass, polyimide (PI) foil, or polyethylene terephthalate (PET) foil substrates incorporate high-aspect ratio (up to 44:1) ink-jet printed 3D electrode structures with heights up to 1 mm at a pitch of 200 µm, enabling precise recording within cell tissues. The specific shapes of the electrode tips and customizable 3D structures provide great flexibility in electrode placement. The versatility of the 3D MEAs is demonstrated by recording the electrophysiological activity of cortical organoids in situ, paving the way for investigating neural activity under regular or various pathologically altered conditions in vitro in a high throughput manner.
AU  - Kopic, I.*
AU  - Dedousi, P.*
AU  - Schmidt, S.
AU  - Peng, H.*
AU  - Berezin, O.*
AU  - Weise, A.*
AU  - George, R.M.*
AU  - Mayr, C.*
AU  - Westmeyer, G.G.
AU  - Wolfrum, B.*
C1  - 71262
C2  - 55968
CY  - 111 River St, Hoboken, Nj 07030 Usa
TI  - Inkjet-printed 3D electrode arrays for recording signals from cortical organoids.
JO  - Adv. Mater. Technol.
PB  - Wiley
PY  - 2024
SN  - 2365-709X
ER  - 

TY  - JOUR
AB  - Hydrogels with adjustable mechanical properties have been engineered as matrices for mammalian cells and allow the dynamic, mechano-responsive manipulation of cell fate and function. Recent research yields hydrogels, where biological photoreceptors translated optical signals into a reversible and adjustable change in hydrogel mechanics. While their initial application provides important insights into mechanobiology, broader implementation is limited by a small dynamic range of addressable stiffness. Herein, this limitation is overcome by developing a photoreceptor-based hydrogel with reversibly adjustable stiffness from ≈800 Pa to the sol state. The hydrogel is based on star-shaped polyethylene glycol, functionalized with the red/far-red light photoreceptor phytochrome B (PhyB), or phytochrome-interacting factor 6 (PIF6). Upon illumination with red light, PhyB heterodimerizes with PIF6, thus crosslinking the polymers and resulting in gelation. However, upon illumination with far-red light, the proteins dissociate and trigger a complete gel-to-sol transition. The hydrogel's light-responsive mechanical properties are comprehensively characterized and it is applied as a reversible extracellular matrix for the spatiotemporally controlled deposition of mammalian cells within a microfluidic chip. It is anticipated that this technology will open new avenues for the site- and time-specific positioning of cells and will contribute to overcome spatial restrictions.
AU  - Hörner, M.*
AU  - Becker, J.*
AU  - Bohnert, R.*
AU  - Baños, M.*
AU  - Jerez-Longres, C.*
AU  - Mühlhäuser, V.*
AU  - Härrer, D.*
AU  - Wong, T.W.
AU  - Meier, M.
AU  - Weber, W.*
C1  - 68514
C2  - 53662
CY  - 111 River St, Hoboken, Nj 07030 Usa
SP  - 10
TI  - A photoreceptor-based hydrogel with red light-responsive reversible sol-gel transition as transient cellular matrix.
JO  - Adv. Mater. Technol.
VL  - 8
IS  - 16
PB  - Wiley
PY  - 2023
SN  - 2365-709X
ER  -