Performance and biocompatibility of OSTEMER 322 in cell-based microfluidic applications.

The Off-Stoichiometry Thiol-ene and Epoxy (OSTE+) polymer technology has been increasingly utilised in the field of microfluidics and lab-on-a-chip applications. However, the impact of OSTEMER polymers, specifically the OSTEMER 322 formulation, on cell viability has remained limited. In this work, we thoroughly explored the biocompatibility of this commercial OSTEMER formulation, along with various surface modifications, through a broad range of cell types, from fibroblasts to epithelial cells. We employed cell viability and confluence assays to evaluate the performance of the material and its modified variants in cell culturing. The properties of the pristine and modified OSTEMER were also investigated using surface characterization methods including contact angle, zeta potential, and X-ray photoelectron spectroscopy. Mass spectrometry analysis confirmed the absence of leaching constituents from OSTEMER, indicating its safety for cell-based applications. Our findings demonstrated that cell viability on OSTEMER surfaces is sufficient for typical cell culture experiments, suggesting OSTEMER 322 is a suitable material for a variety of cell-based assays in microfluidic devices.

Design and Synthesis of New Sulfonic Acid Functionalized Ionic Liquids as Catalysts for Esterification of Fatty Acids with Bioethanol.

In this study, three types of sulfonic acid group functionalized ionic liquids (SAILs) with a different number of catalytic groups and lipophilicity were synthesized and characterized by FT-IR, NMR, and MS analyses. Their catalytic activities were studied in a model esterification of oleic acid with ethanol; heating in a microwave reactor was also used. The experimental results indicated that SAIL, with the lipophilic alkyl chain, performed the best due to its increased solubility in the reaction mixture. Microwave heating was found to be more effective than conventional heating. Recycling experiments show that these novel SAILs can be reused without significant loss of the catalytic activity.

Class II biocompatible E-Shell 300 3D printing material causes severe developmental toxicity in Danio rerio embryos and reduced cell proliferation in vitro - implications for 3D printed microfluidics.

Additive manufacturing is a new technology that represents a highly promising, cheap, and efficient solution for the production of various tools in the biomedicine field. In our study, the toxicity of the commercially available E-Shell 300 series photopolymer, which is used in the manufacture of hearing aids and other implants and which could be potentially exploited in microfluidic device fabrication, was tested using in vivo and in vitro biological models. We examined B14 cell proliferation in direct contact with the three-dimensional (3D)-printed material as well as in water extracts to evaluate in vitro cytotoxicity. Similarly, in vivo tests were performed using an OECD-standardized fish embryo acute toxicity (FET) test on Danio rerio embryos in direct contact with the material and in extracts as well. Despite E-Shell 300 3D-printed material being declared as class-IIa biocompatible, in the case of direct contact with both biological models, the results demonstrated a considerable negative impact on cell proliferation and severe developmental toxicity. In this study, up to 84% reduced cell proliferation in vitro and 79% mortality of in vivo models were observed. In contrast, a negligible toxic influence of E-Shell 300 water extracts was present. Four different post-processing treatments to reduce the toxicity were also tested. We observed that post-printing treatment of 3D-printed material in 96% ethanol can reduce embryonic mortality in the FET test by 71% and also completely eliminate negative effects on cell proliferation. We analyzed leachates from the polymeric structures by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy, and we discovered the presence of surfactant residues. In summary, our results indicate the importance of biocompatibility testing of the 3D printing photopolymer material in direct contact with the given biological model. On the other hand, the possibility of eliminating toxic effects by an appropriate post-processing strategy opens the door for broader applications of E-Shell 300 photopolymers in the development of complex microfluidic devices for various biological applications.