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Jin T, Hilburg SL, Alexander-Katz A. Glass transition of random heteropolymers: A molecular dynamics simulation study in melt, in water, and in vacuum. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Computational Study on Interfacial Interactions between Polymethyl Methacrylate-Based Bone Cement and Hydroxyapatite in Nanoscale. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11072937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Polymethyl methacrylate (PMMA)-based bone cement (BC) is a key material in joint replacement surgery that transfers external forces from the implant to the bone while allowing their robust binding. To quantitatively evaluate the effect of polymerization on the thermomechanical properties of the BC and on the interaction characteristics with the bone ceramic hydroxyapatite (HAp), molecular dynamics simulations were performed. The mechanical stiffness of the BC material under external loading increased gradually with the crosslinking reaction occurrence, indicating increasing load transfer between the constituent molecules. In addition, as the individual Methyl Methacrylate (MMA) segments were interconnected in the system, the freedom of the molecular network was largely suppressed, resulting in more thermally stable structures. Furthermore, the pull-out tests using HAp/BC bilayer models under different constraints (BC at 40% and 85%) revealed the cohesive characteristics of the BC with the bone scaffold in molecular detail. The stiffness and the fracture energy increased by 32% and 98%, respectively, with the crosslink density increasing.
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Özsoylu D, Isık T, Demir MM, Schöning MJ, Wagner T. Cryopreservation of a cell-based biosensor chip modified with elastic polymer fibers enabling ready-to-use on-site applications. Biosens Bioelectron 2021; 177:112983. [PMID: 33535119 DOI: 10.1016/j.bios.2021.112983] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 12/30/2020] [Accepted: 01/05/2021] [Indexed: 12/14/2022]
Abstract
An efficient preservation of a cell-based biosensor chip to achieve a ready-to-use on-site system is still very challenging as the chip contains a living component such as adherent mammalian cells. Herein, we propose a strategy called on-sensor cryopreservation (OSC), which enables the adherent cells to be preserved by freezing (-80 °C) on a biosensor surface, such as the light-addressable potentiometric sensor (LAPS). Adherent cells on rigid surfaces are prone to cryo-injury; thus, the surface was modified to enhance the cell recovery for OSC. It relies on i) the integration of elastic electrospun fibers composed of polyethylene vinyl acetate (PEVA), which has a high thermal expansion coefficient and low glass-transition temperature, and ii) the treatment with O2 plasma. The modified sensor is integrated into a microfluidic chip system not only to decrease the thermal mass, which is critical for fast thawing, but also to provide a precisely controlled micro-environment. This novel cryo-chip system is effective for keeping cells viable during OSC. As a proof-of-concept for the applicability of a ready-to-use format, the extracellular acidification of cancer cells (CHO-K1) was evaluated by differential LAPS measurements after thawing. Results show, for the first time, that the OSC strategy using the cryo-chip allows label-free and quantitative measurements directly after thawing, which eliminates additional post-thaw culturing steps. The freezing of the chips containing cells at the manufacturing stage and sending them via a cold-chain transport could open up a new possibility for a ready-to-use on-site system.
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Affiliation(s)
- Dua Özsoylu
- Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Jülich, 52428, Jülich, Germany; Medical Biology and Genetics, Graduate School of Health Sciences, Dokuz Eylül University, Balcova, 35340, Izmir, Turkey
| | - Tuğba Isık
- Department of Materials Science and Engineering, Izmir Institute of Technology, 35430, Izmir, Turkey; School of Chemistry, University of Bristol, Bristol, UK
| | - Mustafa M Demir
- Department of Materials Science and Engineering, Izmir Institute of Technology, 35430, Izmir, Turkey
| | - Michael J Schöning
- Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Jülich, 52428, Jülich, Germany; Institute of Biological Information Processing (IBI-3), Research Centre Jülich GmbH, 52425, Jülich, Germany.
| | - Torsten Wagner
- Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Jülich, 52428, Jülich, Germany; Institute of Biological Information Processing (IBI-3), Research Centre Jülich GmbH, 52425, Jülich, Germany.
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Preparation of flexible transparent acryl/alumina nano-hybrid materials exhibiting low thermal expansion coefficient. JOURNAL OF POLYMER RESEARCH 2018. [DOI: 10.1007/s10965-018-1627-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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