Evaluation of Specific Classes of Chemical
David Woolley, Adam Woolley in Practical Toxicology, 2017
This simple term covers a vast range of products that can be as simple as a walking stick, as complex as a cardiac pacemaker, or as mundane as a tongue depressor. While medical devices are classified, for regulatory purposes, according to the general level of risk associated with them, for toxicology purposes, they are classifiable by the extent to which they come into contact with the body. A device that will be implanted chronically requires more extensive evaluation than a temporary catheter or a needle and syringe for collecting a blood sample. The extent and duration of contact drive the testing and evaluation program that is required. The toxicity of medical devices is related to a number of aspects of their composition, as is the wider concept of biocompatibility, which relates to how they react with the tissues or fluids that come into contact with them. Biocompatibility can be defined as the ability of a biomaterial to promote a desirable tissue interaction. Since both the nature of the tissue and the response desired vary from case to case, it is a highly application-specific concept. Further layers of complexity are added when the medical device elutes a drug substance or contains an active power source (an active medical device).
Bioresponsive Hydrogels for Controlled Drug Delivery
Deepa H. Patel in Bioresponsive Polymers, 2020
Hydrogels fulfilled two important criteria which are biocompatibility and safety (non-toxic) gained great interest and pertinent in the biomedical field. Polymers must pass cytotoxicity and in vivo toxicity tests. Biocompatibility is the capability of a material to function with an appropriate host response in a specific application. Biocompatibility consists basically of two parameters namely biosafety and bio-functionality Biosafety: It is the adequate host response not only systemic but also local (i.e., surrounding tissue), the absence of cytotoxicity, mutagenesis, and carcinogenesis.Bio-Functionality: It is the capacity of a material to perform the specific task for which it is intended. This explanation is exceptionally applicable in tissue engineering since the nature of tissue construct is to constantly interact with the body through the healing and cellular regeneration process as well as during scaffold degradation. Moreover, initiators, organic solvents, stabilizers, emulsifiers, unreacted monomers, and crosslinkers utilized in polymerization and hydrogel synthesis may be toxic to host cells if they ooze out to tissues or encapsulated cells. To eradicate harmful chemicals from preformed gels, certain purification processes should be implemented such as solvent washing or dialysis [17, 20].
Toward Selectively Toxic Silver Nanoparticles
Huiliang Cao in Silver Nanoparticles for Antibacterial Devices, 2017
Accordingly, biocompatibility should be considered as therapy dependent. The fundamental situation is that biocompatibility is a characteristic of a specific material–biological system and not a property of a material (Williams 2008). The crucial thing to fully understand biocompatibility is to determine which chemical/biochemical, physical/physiological or other mechanisms become operative under a highly specific condition associated with the interactions between biomaterials and the tissues of the body, and what are the consequences of these events (Williams 2008). It should be noted that a material may affect different biological systems in different manners, and it may be time-dependently conditioned after contact and interaction with the tissues. These facts make it crystal clear that ‘there is no material with ubiquitous biocompatibility characteristics and no such things as a uniquely biocompatible material’, and it is essential to clearly interpret the specific application of a material when discussing biocompatibility (Williams 2014).
Finite element analysis of lower limb exoskeleton during sit-to-stand transition
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Umesh K., Vidhyapriya R.
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.
Light mediated drug delivery systems: a review
Published in Journal of Drug Targeting, 2022
Mishal Pokharel, Kihan Park
Their ability to degrade inside the human body and tuneable mechanical, biological, physical, and chemical properties has raised the importance of natural polymers for use in DDS's. Although synthetic polymers have better physical and mechanical properties, natural polymers have the edge due to their biodegradable and biocompatible properties. The biodegradability of polymers emphasises the decomposition of material via living microorganisms through either enzymatic or hydrolytic mechanisms. At the same time, the material is biocompatible when it is not toxic and has no adverse effects on the human body. Biocompatibility is essential when being used for in vivo studies. Biomaterials are widely used for drug delivery systems due to their familiarity with surrounding tissue and their ability to respond to chemical indications from malignant tissues.
Improved intestinal absorption of paclitaxel by mixed micelles self-assembled from vitamin E succinate-based amphiphilic polymers and their transcellular transport mechanism and intracellular trafficking routes
Published in Drug Delivery, 2018
Xiaoyou Qu, Yang Zou, Chuyu He, Yuanhang Zhou, Yao Jin, Yunqiang Deng, Ziqi Wang, Xinru Li, Yanxia Zhou, Yan Liu
Biocompatibility is a great concern for biomedical materials. In order to address the cytocompatibility of micelle-forming materials with Caco-2 cells, their cytotoxicity toward Caco-2 cells by MTT assay was therefore assessed. As shown in Figure 3(E) a relative cell viability ranging from (102.3 ± 5.0)% to (112.5 ± 2.3)% was observed for blank PV-PMs up to the concentration of 12 mg/mL PEOz-VES, suggesting that PEOz-VES exhibited excellent biocompatibility with cells and was a favorable micelle-forming biomaterial for drug delivery. In contrast, the cell viability for blank TPGS1000-PMs-treated group was higher than 82% at concentrations ranging from 0.5 to 12 mg/mL TPGS1000, indicating that TPGS1000 also had better biocompatibility with cells, but it was a little inferior to PEOz-VES. Similarly, the blank Mix-PMs exhibited almost no toxicity against Caco-2 cells up to a concentration of 12 mg/mL polymer. In conclusion, PEOz-VES exhibited higher safety compared with TPGS1000, and the influence of blank PV-PMs and Mix-PMs on cell viability could be ignored in the subsequent studies.
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