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In vitro studies
Published in Ze Zhang, Mahmoud Rouabhia, Simon E. Moulton, Conductive Polymers, 2018
A. Lee Miller, Huan Wang, Michael J. Yaszemski, Lichun Lu
One of the key requirements for biomaterials, conductive or not, is biocompatibility. Ideally, the conductive polymer substrate would support cell growth even without the effects of electrical stimulation. Whether a biomaterial contributes to cell growth is usually tested using cell proliferation assay. A cell line close to the biology of the tissue structure that the biomaterial is intended to replace or reconstruct is chosen for the assay, for example, osteoblasts for bone tissue engineering. For neural applications, the PC12 cell line is widely used due to its extreme versatility for pharmacological manipulation, ease of culture, the large amount of information on their proliferation and differentiation, and their response to extracellular cues such as electrical stimulation (Westerink and Ewing 2008). Since neuron-like cells are anchoring cells, they attach to the culture surface prior to proliferation and extending neurites. By allowing time for the cells to attach before changing the medium (to get rid of floating cells) and staining the cell nucleus and actin cytoskeleton, anchored cells are well visualized for the assessment of cell attachment. Neuronal cell density and the cell coverage of the substrate surface can both reflect the affinity of biomaterials to their biological counterparts. Therefore, the cell attachment assay is generally used to investigate various surface properties of the materials (Bettinger et al. 2009; Bhang et al. 2012; Runge et al. 2010; Lee et al. 2009; Li et al. 2007; Li et al. 2005; Muller et al. 2013; Stauffer and Cui 2006).
Scanning Electrochemical Microscopy of Living Cells
Published in Allen J. Bard, Michael V. Mirkin, Scanning Electrochemical Microscopy, 2022
Changyue Du, Thilini Suduwella, Isabelle Beaulieu, Steen B. Schougaard, Janine Mauzeroll
Takii et al.83 applied SECM to study the spatial distribution of the respiratory activity in PC12 neurons. Monitoring of the O2 concentration profiles around the neuron indicated that both the axon and cell body consume O2. O2 consumption occurs as a result of mitochondrial respiration. Local respiration activity was also observed during axonal growth and was particularly stimulated by the nerve growth factor. Stimulation of PC12 cells by the nerve growth factor is interesting because the cells differentiate into a neuron phenotype by growing a network of narrow (1–2 μm) neurites, which can extend >100 μm from the cell body. Several redox mediators can be used to image both the cell body and neurites: IrCl63−, Ru(NH3)63+, L-ascorbic acid, 1,4-benzoquinone, 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (4-hydroxy TEMPO). The first three mediators are perfectly benign to cells while the last two lead to budding, a morphological indication of progressive cell death.85 As such, budding causes significant morphological changes, which can be imaged by SECM. Given that simultaneous detection of different mediators exhibiting a wide range of redox potential could be desirable, it is possible to rely on fast-scan cyclic voltammetry SECM for imaging the distribution of multiple chemical species near a cell surface.73 In turn, this is interesting because it would expand the amount of electrochemical information acquired through a single measurement. This could be quite beneficial as all mediator response would have been tested on the same living cell exhibiting a given metabolism or phenotypic signature.
Overview of Cell Culture Processes
Published in Wei-Shou Hu, Cell Culture Bioprocess Engineering, 2020
Some cell lines can undergo differentiation in vitro when they are exposed to the appropriate signals. For example, a subclone of 3T3 cells, designated 3T3-L1, can be induced to differentiate into adipocytes.26 PC12 cells, upon exposure to nerve growth factor or dexamethasone, can terminally differentiate into neuron-like cells. The potential of using cell lines capable of differentiation for in vitro drug testing—even for therapy—has been long recognized.
Phytochemical analysis, antioxidant, anticancer and anti-inflammatory activities of Lycium europaeum fruits
Published in International Journal of Environmental Health Research, 2022
Houda Mejri, Ines Ouerghemi, Wissem Aidi Wannes, Faouzia Mahjoub Haddada, Nizar Tlili, Majdi Hammami, Catherine Dussault, Karl Girad-La Lancette, André Pichette, Jean Legault, Moufida Saidani-Tounsi
Ex-vivo cytotoxic activities of L. europaeum fruit extracts were assessed against human carcinoma (A-549), human colorectal (DLD-1) and normal skin fibroblast (WS-1) using both resazurin reduction test and Hoechts assays. Fluorescence measurements were carried out after 48 continuous hours of contact between extracts and cells. Results presented in Table 3 were expressed as the concentration of extracts inhibiting cell growth by 50% (IC50, µg/mL). These results indicated that solvent of different polarities were inactive against all tested cancer cell lines (A-549 and DLD-1) with IC50 values higher than 200 µg/mL. However, these extracts were not found any significant toxicity towards the WS-1 cell line (Table 3) in comparison with anticancer agents, etoposide and betulinol, which shown to have a relatively higher toxicity (IC50 = 12.8 ± 1 and 8 ± 2 µg/mL, respectively). Ghali et al. (2015) found that the aqueous methanol extract of L. europaeum fruits was more effective on rat pheochromocytoma (PC12) cells than A549 ones with only 18% of viable cells left after an exposure to 100 μg/mL of extract. Moreover, the in vitro treatment of cancer Caco-2 cells with L. europaeum fruit oil induced 35% reduction of cell viability at 50 μg/mL of oil by MTT assay and 28% reduction at 100 μg/mL of oil by Alamar Blue assay owing to the presence C18:3 n-3 in oil forming 6% of total fatty acids (Rosa et al. 2017).
Electrospun natural polymer and its composite nanofibrous scaffolds for nerve tissue engineering
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Fangwen Zha, Wei Chen, Lifeng Zhang, Demei Yu
The effects of electrical stimulation on nerve cells can be summarized in the following: (1) improving cell proliferation; (2) promoting neurite growth; (3) affecting neuronal differentiation; (4) modulating neuronal maturation. Table 1 gives a summary of various conditions of electrical stimulation applied in natural polymer based electrospun nanofiber scaffolds. Incorporation PANi to PCL/gelatin nanofibrous scaffold was used to test the influence of ES on the proliferation and differentiation of nerve stem cells (NSCs) [166]. After electrical stimulation, the cell proliferation was enhanced, and the neurite outgrowth was more significantly than the non-stimulated scaffolds. Human induced pluripotent stem cells (hiPSCs)-derived neural stem cells were cultured on the hemin-doped electrospun serum albumin nanofiber scaffolds with trains of 50 ms 50 mV/cm electrical pulses at 2 Hz for 2 h [103]. The scaffold provided a supportive microenvironment for cell proliferation and differentiation. Among all groups, the ES treated hemin-doped electrospun serum albumin scaffold had the longest neurite outgrowth and significantly more neurite branching (Figure 4). Aligned silk fibroin/PANi/PLLA-PCL core-sheath nanofibers scaffold incorporated with nerve growth factor (NGF) was prepared and used to culture PC12 cells [167]. After stimulating with 100 mV/cm for 1 h/day, differentiated cells grown along the major axis direction of conductive nanofibers and exhibited more and longer neurite outgrowth compared with non-stimulated condition.
Effects of green tea polyphenols against metal-induced genotoxic damage: underlying mechanistic pathways
Published in Journal of Toxicology and Environmental Health, Part B, 2023
María Del Carmen García-Rodríguez, Lourdes Montserrat Hernández-Cortés, Víctor Manuel Mendoza-Núñez, Francisco Arenas-Huertero
In studies conducted with rat adrenal pheochromocytoma PC12 cells treated with Co(II), a decrease in DNA fragmentation resulting from treatment with 100 μM of EGCG was observed, demonstrating the neuroprotective effect of this polyphenol (Jung et al. 2007). Similarly, Alshatwi et al. (2014) noted that treatments with 10 or 20 μM of catechin exhibited antigenotoxic effects by diminishing DNA fragmentation in human lymphocytes treated with Cd(II). Further, Wu et al. (2012) found that even at a concentration of 25 μM of EGCG, there was a significant fall in DNA-protein crosslinks associated with restoration of the DNA content in human bronchial epithelial cells incubated with Cr(VI).