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Hyaluronan-Based Hydrogels as Functional Vectors for Standardised Therapeutics in Tissue Engineering and Regenerative Medicine
Published in Harishkumar Madhyastha, Durgesh Nandini Chauhan, Nanopharmaceuticals in Regenerative Medicine, 2022
Alexandre Porcello, Alexis Laurent, Nathalie Hirt-Burri, Philippe Abdel-Sayed, Anthony de Buys Roessingh, Wassim Raffoul, Olivier Jordan, Eric Allémann, Lee Ann Applegate
For any type of product registration, adequate preclinical demonstration of safety (i.e. proof that the product is not pyrogenic, mutagenic, toxigenic, genotoxic, hemolytic, or immunogenic) must be provided. For medical devices, biocompatibility (i.e. assessment of cytotoxicity, sensitisation, and irritation/intracutaneous reactivity) and biodistribution must be documented within specific requirements, depending on the device type, category, residence time, and type of use (Huerta-Ángeles et al. 2018). In vitro acute cytotoxicity may be studied using adequate cell lines of cell types, within validated models coherent with the intended application (i.e. homologous with implantation site), and adequate methodology-specific sample preparation (e.g. extract-dilution method, test by direct contact, or indirect contact). Accepted readout methodologies for cytocompatibility testing comprise neutral red uptake (NRU), MTT (methyl thiazolyltetrazolium), XTT, resazurin assay, ATP concentration measurement, crystal violet staining, or DNA content measurement. For further preclinical safety evaluations, in vivo models (e.g. mice, guinea pigs, rats, rabbits, sheep) may be considered on an application-dependent basis, for evaluation (i.e. macroscopic description and histopathology) of the tissular response after product application. Such assays need to be devised based on projected product degradation rates, types of tissues exposed, and intended clinical exposure times, and may be used as safety demonstration before clinical testing of efficacy (Huerta-Ángeles et al. 2018).
Bio-Implants Derived from Biocompatible and Biodegradable Biopolymeric Materials
Published in P. Mereena Luke, K. R. Dhanya, Didier Rouxel, Nandakumar Kalarikkal, Sabu Thomas, Advanced Studies in Experimental and Clinical Medicine, 2021
Polymers are highly corrosion resistant and wear-resistant materials. This material is highly biocompatible with the human body and suitable for the bioimplantation. The bone properties depend on the age and vary with factors like torsion, compression, tension, and bending. These factors would be easily matched with polymer materials as it has the best mechanical properties for better implants. Polymers are the highest percentage of materials with the properties also with the better biocompatibility can act as the reference material in place of ceramics and metals.
Complications of Fillers and Their Management
Published in Neil S. Sadick, Illustrated Manual of Injectable Fillers, 2020
The FDA process of ensuring the safety and efficacy of dermal fillers includes the submission of protocol preclinical studies, clinical studies, and in some cases postapproval studies. Dermal fillers fall under the category of medical device and not drug, so the number of subjects and extent of testing is less than that required for drug approval. The preclinical studies, including the biocompatibility, implantation, and viral inactivation studies, that have been conducted for the various fillers are listed in Table 15.2. Biocompatibility studies may include chemical analysis, cytotoxicity, and genotoxicity.
Titanium surface polyethylene glycol hydrogel and gentamicin-loaded cross-linked starch microspheres release system for anti-infective drugs
Published in Journal of Drug Targeting, 2023
Yunfeng Wu, Fanqi Hu, Xiaoqing Yang, Shaofu Zhang, Chengqi Jia, Xiaole Liu, Xuesong Zhang
Biocompatibility is the primary requirement for the development of implantable medical materials [27]. The material often produces different degrees of physicochemical stimulation to the body tissue cells after implantation, such as causing connective tissue hyperplasia, tissue calcification and other reactions [28]. The endophytic composite coating should have good compatibility to ensure the safety of clinical application. In vivo implantation assay is a common means to test biocompatibility. After implanting the material into animals for a certain period of time, the immune response generated by the surrounding tissues is observed and evaluated by histological analysis. SusmitaBose et al. [29] found increased bone formation and facilitated wound healing and tissue regeneration in a curcumin-containing polyε-caprolactone, polyethylene glycol and polylactic acid copolymer-coated titanium scaffold drug delivery system. In this experiment, after comparing the drug-loaded composite coated titanium with the uncoated titanium, we found that the proliferation of surrounding fibrous tissues, inflammatory response and bone tissue changes were basically the same between the two groups during the same period of time, indicating that the drug-loaded composite coating did not cause serious inflammatory response and had good biocompatibility in vivo.
Antimicrobial activity of flavonoids glycosides and pyrrolizidine alkaloids from propolis of Scaptotrigona aff. postica
Published in Toxin Reviews, 2023
T. M. Cantero, P. I. Silva Junior, G. Negri, R. M. Nascimento, R. Z. Mendonça
Cytotoxicity and biocompatibility tests simulate biological reactions to bioactive molecules, when they are placed in contact with cells and body tissues. The use of cell lines can predict whether a molecule might be toxic to the body, since it is possible to measure how much the cell metabolism was affected during the test. Although tests assessing cytotoxicity in vitro may not have correlation with in vivo tests, if a propolis extract induces a proven cytotoxic reaction in cell culture tests, it is much likely that it will develop toxicity when used in foods, treatment of diseases and cosmetics (Saavedra et al. 2016, Utispan et al. 2017). The cell viability test was carried out using 3- (4,5- dimethylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide (MTT) reduction assay used to assess cell metabolic activities and to measure the cytotoxic or cytostatic activities of potential medicinal agents and toxic materials. Thus, cytotoxicity that can cause damage by decreasing the number of active mitochondria in the cells can be evaluated through the water-soluble yellow dye MTT, which is converted into an insoluble purple formazan by the action of mitochondrial reductase through oxidoreductase enzymes.
Finite element analysis of lower limb exoskeleton during sit-to-stand transition
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
The materials proposed for realizing the analysis are alloy steel, 1060 aluminum alloy, and titanium with yield strength 620 MPa, 27 MPa, and 140 MPa, respectively. The material selection for the exoskeleton is based upon cost, availability, and durability. The materials should withstand the load during standing, walking, and climbing. One limb is assumed to bear the entire load of the body as observed by the gait pattern during walk. In designing a device intended for human usage, biocompatibility is essential. The selected materials are already proven to be biocompatible. The device is designed to use external to the human being and there are no implantable parts; moreover, the patients will be wearing dress and above which the device is attached. So, the chances of device-skin interactions are less. In this scenario, any materials without skin irritations are applicable for exoskeleton.