Novel Deproteinized Natural Rubber Latex Adhesive Used in Extraoral Maxillofacial Prostheses

This study aimed to develop an adhesive for silicone maxillofacial prostheses and compared the properties with the Daro adhesive hydrobond (Factor II, Inc, Lakeside, AZ, USA). Two adhesives were developed from non-vulcanized natural rubber-based adhesives (Adhesive A) and deproteinized natural rubber latex (DNRL) products (Adhesive B) and stored at 4 °C. The Control group was the commercial Daro adhesive hydrobond (Factor II, Inc, Lakeside, AZ, USA). The physical properties (appearance, viscosity, spreadability, color, and pH) of the adhesives were measured and every week for 12 weeks after storing at 4 °C. The adhesives were characterized under scanning electron microscopy. Mechanical testing done were peel bond strength and biocompatibility testing was done using MTT assay. Physical, surface, and mechanical properties were compared with the commercial adhesive. Data analysis was done using SPSS version 24. Both adhesives were physically and chemically stable at temperature 4 °C and had suitable peel bond strength adhesives as the commercial adhesive. Hence, the adhesives can be used to adhere to the maxillofacial silicone prostheses.

Biocompatibility Testing of Liquid Metal as an Interconnection Material for Flexible Implant Technology

Galinstan, a liquid metal at room temperature, is a promising material for use in flexible electronics. Since it has been successfully integrated in devices for external use, e.g., as stretchable electronic skin in tactile sensation, the possibility of using galinstan for flexible implant technology comes to mind. Usage of liquid metals in a flexible implant would reduce the risk of broken conductive pathways in the implants and therefore reduce the possibility of implant failure. However, the biocompatibility of the liquid metal under study, i.e., galinstan, has not been proven in state-of-the-art literature. Therefore, in this paper, a material combination of galinstan and silicone rubber is under investigation regarding the success of sterilization methods and to establish biocompatibility testing for an in vivo application. First cell biocompatibility tests (WST-1 assays) and cell toxicity tests (LDH assays) show promising results regarding biocompatibility. This work paves the way towards the successful integration of stretchable devices using liquid metals embedded in a silicone rubber encapsulant for flexible surface electro-cortical grid arrays and other flexible implants.

Quantitative evaluation of cell morphology and material interactions on opaque biomaterials

One of the key aspects in the development of novel implants is to find suitable materials and understand the mechanisms that occur when a material is exposed to the tissues of the human body. These mechanisms are commonly referred to as the biocompatibility of the material. A better understanding of the tissue-material interactions becomes more urgent as biomaterials are used in wide-ranging applications like modern medical devices. However, most biomaterials used for implants are opaque, resulting in difficulties for the microscopical evaluation during in vitro biocompatibility testing. Particularly, cell morphology and adhesion capabilities of cells can provide insights in the interactions between implant materials and tissues at the implant site. To improve our capabilities in biocompatibility testing of novel biomaterials we applied a new method to quantitatively assess cellular parameters on opaque samples using fluorescence microscopy and bio-image analysis.

In vitro biocompatibility testing of polymeric nanofiber scaffolds: fine-tuning for a better prediction of the in vivo behaviour

Biomaterial research efforts focus on the development of biomaterials that mimic the natural extracellular environment. In addition, different strategies are applied to render materials for blood-contacting devices nonthrombogenic through surface modifications that would suppress activation of platelets, coagulation and the complement system. A confluent thin layer of endothelial cells lines all blood vessels and produces factors responsible for inhibition of coagulation, thrombosis and neointimal hyperplasia. Thus, the ability to rapidly form a healthy endothelium upon implantation represents a desired property of biomaterials used for cardiovascular devices. In this study we used advanced in vitro methods to investigate the biocompatibility of a biodegradable and a permanent electrospun nanofiber fabric, poly-L-lactic acid and polycarbonate-based silicone elastomer respectively, with the focus on endothelialization and hemocompatibility.

Biocompatibility of Medical Devices - A Review

BACKGROUND Biomaterial is defined as "any substance or combination of medicine, artificial or natural origin, which can be used at any time, in whole or part by a system that controls, adds to, or restores any tissue, organ or function". ISO 10993-1: 2018 standard defines bio compliance law as "the ability of a medical device or tool to perform a selected program with the acceptable response of experts". Incompatible factors cause chemical reactions in patients, with little or no side effects. The body can respond in a sort of way after the installation of medical devices, so testing and improvement is important here. Therefore, testing and improvement in this field are important. Biocompatibility is required for any significant use of components or materials in medical devices. Inconsistent factors create negative biological responses in patients, which may have serious consequences. Biomaterials are substances utilized in medical devices, especially in applications where the device is touched, temporarily embedded, or permanently implanted within the body. Because of the significant impact of biocompatibility, many countries have imposed regulations on medical device manufacturers to meet biocompatibility specifications. Here is a brief explanation about the biocompatibility and incompatibility parameters of medical devices with a human body and its need for biocompatibility of medical devices with the human body. Medical devices have improved doctors' ability to diagnose and treat disease, which has led to significant improvements in health and quality of life. Thus, medical devices are prone to various incompatibility issues and procedures that affect the biological environment must be followed. KEY WORDS Biocompatibility, Material Interactions, Sterilization, Medical devices, Biocompatibility Testing, Incompatibility Factors.

Biocompatibility testing of composite biomaterial designed for a new petal valve construction for pulsatile ventricular assist device

This paper presents the results of biocompatibility testing performed on several biomaterial variants for manufacturing a newly designed petal valve intended for use in a pulsatile ventricular assist device or blood pump. Both physical vapor deposition (PVD) and plasma-enhanced chemical vapor deposition (PECVD) were used to coat titanium-based substrates with hydrogenated tetrahedral amorphous carbon (ta-C:H) or amorphous hydrogenated carbon (a-C:H and a-C:H, N). Experiments were carried out using whole human blood under arterial shear stress conditions in a cone-plate analyzer (ap. 1800 1/s). In most cases, tested coatings showed good or very good haemocompatibility. Type a-C:H, N coating proved to be superior in terms of activation, risk of aggregation, and the effects of generating microparticles of apoptotic origin, and also demonstrated excellent mechanical properties. Therefore, a-C:H, N coatings were selected for further in vivo studies. In vivo animal studies were carried out according to the ISO 10993 standard. Intradermal reactivity was assessed in three rabbits and sub-acute toxicity and local effects after implantation were examined in 12 rabbits. Based on postmortem examination, no organ failure or wound tissue damage occurred during the required period of observation. In summary, our investigations demonstrated high biocompatibility of the biomaterials in relation to thrombogenicity, toxicity, and wound healing. Prototypes of the petal valves were manufactured and mounted on the pulsatile ventricular assist device. Hydrodynamic features and impact on red blood cells (hemolysis) as well as coagulation (systemic thrombogenicity) were assessed in whole blood.

Design Requirements for Scapholunate Interosseous Ligament Reconstruction

Background As numerous repairs, reconstructions, and replacements have been used following scapholunate interosseous ligament (SLIL) injury, there is a need to define the structural requirements for any reconstruction or replacement. Methods Research has been conducted on the force needed to keep the scaphoid and lunate reduced following simulated injury, the failure force of the native SLIL and various replacements, the stiffness of the SLIL and replacements, and the torsional resistance of the scaphoid relative to the lunate. Results Forces on the order of 50 N are needed to keep the scaphoid and lunate reduced during simple wrist motions in the chronically injured wrist. Even greater forces (up to 110 N) are needed to keep the bones reduced during strenuous activities, such as pushups. The failure force of the entire SLIL has been reported to be as high as 350 N and the failure force of just the dorsal component of the SLIL to be 270 N. Conclusions The design requirements for a reconstruction or repair may vary depending upon the demands of the patient. In a high demand patient, a reconstruction needs to support the above-mentioned forces during cyclic loading (50 N), when performing strenuous activities (110 N), or during a fall (at least 350 N). Any artificial replacement must undergo careful biocompatibility testing.