TY  - JOUR
A1  - Karakaya, Emine
A1  - Bider, Faina
A1  - Frank, Andreas
A1  - Teßmar, Jörg
A1  - Schöbel, Lisa
A1  - Forster, Leonard
A1  - Schrüfer, Stefan
A1  - Schmidt, Hans-Werner
A1  - Schubert, Dirk Wolfram
A1  - Blaeser, Andreas
A1  - Boccaccini, Aldo R.
A1  - Detsch, Rainer
T1  - Targeted printing of cells: evaluation of ADA-PEG bioinks for drop on demand approaches
JF  - Gels
N2  - A novel approach, in the context of bioprinting, is the targeted printing of a defined number of cells at desired positions in predefined locations, which thereby opens up new perspectives for life science engineering. One major challenge in this application is to realize the targeted printing of cells onto a gel substrate with high cell survival rates in advanced bioinks. For this purpose, different alginate-dialdehyde—polyethylene glycol (ADA-PEG) inks with different PEG modifications and chain lengths (1–8 kDa) were characterized to evaluate their application as bioinks for drop on demand (DoD) printing. The biochemical properties of the inks, printing process, NIH/3T3 fibroblast cell distribution within a droplet and shear forces during printing were analyzed. Finally, different hydrogels were evaluated as a printing substrate. By analysing different PEG chain lengths with covalently crosslinked and non-crosslinked ADA-PEG inks, it was shown that the influence of Schiff's bases on the viscosity of the corresponding materials is very low. Furthermore, it was shown that longer polymer chains resulted in less stable hydrogels, leading to fast degradation rates. Several bioinks highly exhibit biocompatibility, while the calculated nozzle shear stress increased from approx. 1.3 and 2.3 kPa. Moreover, we determined the number of cells for printed droplets depending on the initial cell concentration, which is crucially needed for targeted cell printing approaches.
KW  - bioprinting
KW  - drop on demand
KW  - sodium alginate
KW  - polyethylene glycol
KW  - shear stress
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-267317
SN  - 2310-2861
VL  - 8
IS  - 4
ER  - 
TY  - JOUR
A1  - Rupp, Mira T.
A1  - Auvray, Thomas
A1  - Hanan, Garry S.
A1  - Kurth, Dirk G.
T1  - Electrochemical and photophysical study of homoleptic and heteroleptic methylated Ru(II) Bis-terpyridine complexes
JF  - European Journal of Inorganic Chemistry
N2  - In this study, we investigate the impact of N-methylation on the electronic and photophysical properties of both homoleptic and heteroleptic Ru(II) bis-terpyridine complexes based on the recently reported ligand 4’-(4-bromophenyl)-4,4’’’: 4’’,4’’’’-dipyr-idinyl-2,2’ : 6’,2’’-terpyridine (Bipytpy), with pyridine substituents in the 4- and 4’’-position. The first reduction of the methylated complexes takes place at the pyridinium site and is observed as multi-electron process. Following N-methylation, the complexes exhibit higher luminescence quantum yields and longer excited-state lifetimes. Interestingly, the photophysical properties of the heteroleptic and homoleptic complexes are rather similar. TD-DFT calculations support the experimental results. Furthermore, the complexes are tested as photosensitizers for photocatalytic hydrogen production, as the parent complex 1[Ru(Bipytpy)(Tolyltpy)](PF \(_6\))\(_2\) (Tolyltpy: 4’-tolyl-2,2’: 6’,2’’-terpyri-dine) was recently shown to be active and highly stable underphotocatalytic conditions. However, the methylated complexes reported herein are inactive as photosensitizers under the chosen conditions, presumably due to loss of the methyl groups, converting them to the non-methylated parent complexes.
KW  - Ruthenium
KW  - Luminescence
KW  - Electrochemistry
KW  - Ligand effects
KW  - Photocatalysis
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-248769
VL  - 2021
IS  - 28
SP  - 2822
EP  - 2829
ER  - 
TY  - JOUR
A1  - Chilaka, Cynthia Adaku
A1  - Obidiegwu, Jude Ejikeme
A1  - Chilaka, Augusta Chinenye
A1  - Atanda, Olusegun Oladimeji
A1  - Mally, Angela
T1  - Mycotoxin regulatory status in Africa: a decade of weak institutional efforts
JF  - Toxins
N2  - Food safety problems are a major hindrance to achieving food security, trade, and healthy living in Africa. Fungi and their secondary metabolites, known as mycotoxins, represent an important concern in this regard. Attempts such as agricultural, storage, and processing practices, and creation of awareness to tackle the menace of fungi and mycotoxins have yielded measurable outcomes especially in developed countries, where there are comprehensive mycotoxin legislations and enforcement schemes. Conversely, most African countries do not have mycotoxin regulatory limits and even when available, are only applied for international trade. Factors such as food insecurity, public ignorance, climate change, poor infrastructure, poor research funding, incorrect prioritization of resources, and nonchalant attitudes that exist among governmental organisations and other stakeholders further complicate the situation. In the present review, we discuss the status of mycotoxin regulation in Africa, with emphasis on the impact of weak mycotoxin legislations and enforcement on African trade, agriculture, and health. Furthermore, we discuss the factors limiting the establishment and control of mycotoxins in the region.
KW  - fungi
KW  - mycotoxin
KW  - legislation
KW  - food safety
KW  - food security
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-278941
SN  - 2072-6651
VL  - 14
IS  - 7
ER  -