scholarly journals Ceramic Packaging in Neural Implants

2020 ◽  
Author(s):  
Konlin Shen ◽  
Michel M. Maharbiz
Keyword(s):  
Thin Film ◽  
Traditional Approach ◽  
Semiconductor Industry ◽  
High Strength ◽  
Ceramic Materials ◽  
The Body ◽  
Medical Implants ◽  
Neural Implants ◽  
Housing Materials

AbstractThe lifetime of neural implants is strongly dependent on packaging due to the aqueous and biochemically aggressive nature of the body. Over the last decade, there has been a drive towards neuromodulatory implants which are wireless and approaching millimeter-scales with increasing electrode count. A so-far unrealized goal for these new types of devices is an in-vivo lifetime comparable to a sizable fraction of a healthy patient’s lifetime (>10-20 years). Existing, approved medical implants commonly encapsulate components in metal enclosures (e.g. titanium) with brazed ceramic inserts for electrode feedthrough. It is unclear how amenable the traditional approach is to the simultaneous goals of miniaturization, increased channel count, and wireless communication. Ceramic materials have also played a significant role in traditional medical implants due to their dielectric properties, corrosion resistance, biocompatibility, and high strength, but are not as commonly used for housing materials due to their brittleness and the difficulty they present in creating complex housing geometries. However, thin film technology has opened new opportunities for ceramics processing. Thin films derived largely from the semiconductor industry can be deposited and patterned in new ways, have conductivities which can be altered during manufacturing to provide conductors as well as insulators, and can be used to fabricate flexible substrates. In this review, we give an overview of packaging for neural implants, with an emphasis on how ceramic materials have been utilized in medical device packaging, as well as how ceramic thin film micromachining and processing may be further developed to create truly reliable, miniaturized, neural implants

scholarly journals An Overview on the Tribological Performance of Titanium Alloys with Surface Modifications for Biomedical Applications

Lubricants ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 65 ◽  
Author(s):  
Kaur ◽  
Ghadirinejad ◽  
Oskouei
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Titanium Alloys ◽  
Weight Ratio ◽  
High Strength ◽  
Surface Modifications ◽  
Tribological Performance ◽  
The Body ◽  
High Wear Resistance ◽  
Medical Implants

The need for metallic biomaterials will always remain high with their growing demand in joint replacement in the aging population. This creates need for the market and researchers to focus on the development and advancement of the biometals. Desirable characteristics such as excellent biocompatibility, high strength, comparable elastic modulus with bones, good corrosion resistance, and high wear resistance are the significant issues to address for medical implants, particularly load-bearing orthopedic implants. The widespread use of titanium alloys in biomedical implants create a big demand to identify and assess the behavior and performance of these alloys when used in the human body. Being the most commonly used metal alloy in the fabrication of medical implants, mainly because of its good biocompatibility and corrosion resistance together with its high strength to weight ratio, the tribological behavior of these alloys have always been an important subject for study. Titanium alloys with improved wear resistance will of course enhance the longevity of implants in the body. In this paper, tribological performance of titanium alloys (medical grades) is reviewed. Various methods of surface modifications employed for titanium alloys are also discussed in the context of wear behavior.

scholarly journals Automated Reactive Accelerated Aging for Rapid In Vitro Evaluation of Neural Implants Performance

2017 ◽  
Author(s):  
Matthew G. Street ◽  
Cristin G. Welle ◽  
Pavel A. Takmakov
Keyword(s):  
Hydrogen Peroxide ◽  
Accelerated Aging ◽  
Cost Effective ◽  
The Body ◽  
Throughput Optimization ◽  
Neural Implants ◽  
Aging Conditions ◽  
Miniaturized Devices

AbstractObjectiveNovel therapeutic applications for neural implants require miniaturized devices. Pilot clinical studies suggest that rapid failure of the miniaturized neural implants in the body presents a major challenge for this type of technology. Miniaturization imposes stricter requirements for reliability of materials and designs. Evaluation of neural implant performance over clinically relevant timescales presents time-and cost-prohibitive challenges for animal models.ApproachIn vitro reactive accelerated aging (RAA) was developed to expedite durability testing of these devices. RAA simulates an aggressive physiological environment associated with an immune response and implicated in device failure. It uses hydrogen peroxide, which mimics reactive oxygen species (ROS), and high temperature to accelerate chemical reactions that lead to device degradation. RAA accurately simulates the degradation pattern of neural implants observed in vivo, but requires daily maintenance and is prone to variability in performance.Main resultsThis work introduces automated reactive accelerated aging (aRAA) that is compatible with multiplexing. The core of aRAA is electrochemical detection for feedback control of hydrogen peroxide concentration, implemented with simple off-the shelf components.SignificanceaRAA allows multiple parallel experiments for a high-throughput optimization of reactive aging conditions to more quickly and more rigorously simulate the in vivo environment. aRAA is a cost-effective tool for rapid in vitro evaluation of durability of neural implants, ultimately expediting the development of a new generation of miniaturized devices with long functional lifespans.

Hydration and Crosslinking Effects on the Elastic and Viscoelastic Properties of Collagen Scaffolds

2011 ◽  
Author(s):  
Bin Xu ◽  
Katherine Yanhang Zhang
Keyword(s):  
Thin Film ◽  
Solid Phase ◽  
Great Influence ◽  
Collagen Gel ◽  
Fluid Phase ◽  
The Body ◽  
Collagen Gels ◽  
Collagen Scaffolds ◽  
Fiber Network

Collagen is the most abundant protein in the body. It plays critical roles in many supporting and connecting tissues such as tendon, ligament, bone, blood vessels, skin, etc. Collagen gels prepared from commercially available collagen solutions mimic the in vivo environment and have been widely used as three-dimensional (3-D) tissue scaffolds for cell culture. Collagen thin film is the dehydrated form of collagen gel. A number of studies have examined the cell-collagen thin film interactions (1, 2). As a biphasic material, collagen scaffolds contain a solid phase which represents by collagen fiber network and an interstitial fluid phase (3). This special structure makes collagen a viscoelastic material. Viscoelasticity is related to force or energy storage, transmission and dissipation in tissues and has a great influence on the growth and development of cells (4).

Development of Biocompatible Y-Stabilized ZrO2 Fabricated by Spark Plasma Sintering

2012 ◽  
Vol 86 ◽  
pp. 17-21 ◽  
Author(s):  
H. Sakai ◽  
Teruo Asaoka
Keyword(s):  
Bone Tissue ◽  
Tetragonal Zirconia ◽  
High Strength ◽  
The Body ◽  
Apatite Layer ◽  
Material Surface ◽  
Zirconia Ceramics ◽  
Hip Prostheses ◽  
Plasma Sintering

Due to the merits of zirconia ceramics such as high strength, toughness, abrasion resistance, and chemical stability in vivo, yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) are currently used in the femoral head of hip prostheses. However, this material has a limited applications range because it is a bioinert material that does not interact with bone tissue and thus does not easily integrate directly in the bone. Therefore, we need to add different material’s layer which enables in vivo formation of bone-like apatite layer that exhibits bioactivity , composite compound bioactive ceramics, and facilitates interactions and integration in bone tissue. In addition, by developing a surface structure that enhances mechanical bonding, this material can be expected to be used as an alternative aggregate under load bearing conditions. In the present study, various method were carried out with the objective of controlling interactions between zirconia ceramics and the body such as structural design of the material surface, addition of bioactivity using reagents treatment, confirmation of formation of the apatite layer using immersion in simulated body fluid, wettability testing and develop structure with mechanical properties equal to bone strength.

scholarly journals Contemporary All-ceramic Systems – Part 2

2007 ◽  
Vol 50 (2) ◽  
pp. 105-107 ◽  
Author(s):  
Shriharsha Pilathadka ◽  
Dagmar Vahalová
Keyword(s):  
Success Rate ◽  
Fracture Resistance ◽  
Clinical Success ◽  
High Strength ◽  
Ceramic Materials ◽  
In Vivo Studies ◽  
High Fracture ◽  
All Ceramic

Current all-ceramic materials offer a accepted level of fracture resistance, fit and aesthetics. High fracture resistance recommends it to be a material to support fixed partial denture (FPD) in a stress bearing area with clinical success. This part of the present literature review covers the success rate, selection criteria of all ceramic systems, cementation technique, finishing and polishing. In vitro and in vivo studies of new high strength ceramics were well documented. Data suggest that single crowns in the anterior and posterior region are more predictable than bridges. Well-studied longterm success rate for FPDs are very limited.

Addition of Surface Function to Zirconia for Biomaterial Use

2008 ◽  
Vol 57 ◽  
pp. 139-143 ◽  
Author(s):  
N. Koide ◽  
K. Suzuki ◽  
M. Tsuda ◽  
Teruo Asaoka
Keyword(s):  
Bone Tissue ◽  
Tetragonal Zirconia ◽  
High Strength ◽  
Limited Range ◽  
The Body ◽  
Apatite Layer ◽  
Material Surface ◽  
Zirconia Ceramics ◽  
Hip Prostheses

Due to the merits of zirconia ceramics such as high strength, toughness, and abrasion resistance, as well as chemical stability in vivo, yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) are currently used in the femoral head of hip prostheses. However, this material has a limited range of use because it is a bioinert material that does not interact with bone tissue and thus does not easily integrate directly with bone. Therefore, addition of a material surface that enables the in vivo formation of a bone-like apatite layer that exhibits bioactivity and facilitates interactions and integration with bone tissue is desired. In addition, by developing a surface structure that enhances mechanical bonding, this material can be expected to be used as an alternative aggregate under load bearing conditions. In the present study, structural design of the material surface, addition of bioactivity using reagents treatment, confirmation of formation of the apatite layer using immersion in simulated body fluid, mechanical assessment, and wettability testing were conducted with the objective of controlling interactions between zirconia ceramics and the body.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Ceramic Materials. Effects of Fracture Origin and Microstructure on Bending Strength of High-Strength Si3N4.

1994 ◽  
Vol 43 (489) ◽  
pp. 599-605 ◽  
Author(s):  
Akira YAMAKAWA ◽  
Takehisa YAMAMOTO ◽  
Tomoyuki AWAZU ◽  
Kenji MATSUNUMA ◽  
Takao NISHIOKA
Keyword(s):  
Bending Strength ◽  
High Strength ◽  
Ceramic Materials ◽  
Fracture Origin

Репрограммированые in vitro на М3 фенотип макрофаги останавливают рост солидной карциномы in vivo

2018 ◽  
pp. 41-46
Author(s):  
А.А. Раецкая ◽  
С.В. Калиш ◽  
С.В. Лямина ◽  
Е.В. Малышева ◽  
О.П. Буданова ◽  
...  
Keyword(s):  
Solid Tumor ◽  
Antitumor Effect ◽  
Tumor Development ◽  
Significant Inhibition ◽  
The Body ◽  
Ehrlich Carcinoma ◽  
Solid Carcinoma ◽  
Ec Cells

Цель исследования. Доказательство гипотезы, что репрограммированные in vitro на М3 фенотип макрофаги при введении в организм будут существенно ограничивать развитие солидной карциномы in vivo . Методика. Рост солидной опухоли инициировали у мышей in vivo путем подкожной инъекции клеток карциномы Эрлиха (КЭ). Инъекцию макрофагов с нативным М0 фенотипом и с репрограммированным M3 фенотипом проводили в область формирования солидной КЭ. Репрограммирование проводили с помощью низких доз сыворотки, блокаторов факторов транскрипции STAT3/6 и SMAD3 и липополисахарида. Использовали две схемы введения макрофагов: раннее и позднее. При раннем введении макрофаги вводили на 1-е, 5-е, 10-е и 15-е сут. после инъекции клеток КЭ путем обкалывания макрофагами с четырех сторон область развития опухоли. При позднем введении, макрофаги вводили на 10-е, 15-е, 20-е и 25-е сут. Через 15 и 30 сут. после введения клеток КЭ солидную опухоль иссекали и измеряли ее объем. Эффект введения макрофагов оценивали качественно по визуальной и пальпаторной характеристикам солидной опухоли и количественно по изменению ее объема по сравнению с группой без введения макрофагов (контроль). Результаты. Установлено, что M3 макрофаги при раннем введении от начала развития опухоли оказывают выраженный антиопухолевый эффект in vivo , который был существенно более выражен, чем при позднем введении макрофагов. Заключение. Установлено, что введение репрограммированных макрофагов M3 ограничивает развитие солидной карциномы в экспериментах in vivo . Противоопухолевый эффект более выражен при раннем введении М3 макрофагов. Обнаруженные в работе факты делают перспективным разработку клинической версии биотехнологии ограничения роста опухоли, путем предварительного программирования антиопухолевого врожденного иммунного ответа «в пробирке». Aim. To verify a hypothesis that macrophages reprogrammed in vitro to the M3 phenotype and injected into the body substantially restrict the development of solid carcinoma in vivo . Methods. Growth of a solid tumor was initiated in mice in vivo with a subcutaneous injection of Ehrlich carcinoma (EC) cells. Macrophages with a native M0 phenotype or reprogrammed towards the M3 phenotype were injected into the region of developing solid EC. Reprogramming was performed using low doses of serum, STAT3/6 and SMAD3 transcription factor blockers, and lipopolysaccharide. Two schemes of macrophage administration were used: early and late. With the early administration, macrophages were injected on days 1, 5, 10, and 15 following the injection of EC cells at four sides of the tumor development area. With the late administration, macrophages were injected on days 10, 15, 20, and 25. At 15 and 30 days after the EC cell injection, the solid tumor was excised and its volume was measured. The effect of macrophage administration was assessed both qualitatively by visual and palpation characteristics of solid tumor and quantitatively by changes in the tumor volume compared with the group without the macrophage treatment. Results. M3 macrophages administered early after the onset of tumor development exerted a pronounced antitumor effect in vivo , which was significantly greater than the antitumor effect of the late administration of M3 macrophages. Conclusion. The observed significant inhibition of in vivo growth of solid carcinoma by M3 macrophages makes promising the development of a clinical version of the biotechnology for restriction of tumor growth by in vitro pre-programming of the antitumor, innate immune response.

Ruthenium Complexes for 1- and 2-Photon Photodynamic Therapy: From In Silico Prediction to In Vivo Applications

2020 ◽  
Author(s):  
Johannes Karges ◽  
Shi Kuang ◽  
Federica Maschietto ◽  
Olivier Blacque ◽  
Ilaria Ciofini ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
In Silico ◽  
Aqueous Solubility ◽  
The Body ◽  
Photon Absorption ◽  
Multicellular Tumor Spheroids ◽  
Spectral Window ◽  
Photon Excitation ◽  
Polypyridine Complexes

<div>The use of photodynamic therapy (PDT) against cancer has received increasing attention overthe recent years. However, the application of the currently approved photosensitizers (PSs) is somehow limited by their poor aqueous solubility, aggregation, photobleaching and slow clearance from the body. To overcome these limitations, there is a need for the development of new classes of PSs with ruthenium(II) polypyridine complexes currently gaining momentum. However, these compounds generally lack significant absorption in the biological spectral window, limiting their application to treat deep-seated or large tumors. To overcome this drawback, ruthenium(II) polypyridine complexes designed in silico with (E,E’)-4,4´-bisstyryl 2,2´-bipyridine ligands showed impressive 1- and 2-Photon absorption up to a magnitude higher than the ones published so far. While non-toxic in the dark, these compounds were found phototoxic in various 2D monolayer cells, 3D multicellular tumor spheroids and be able to eradicate a multiresistant tumor inside a mouse model upon clinically relevant 1-Photon and 2 Photon excitation.</div>

Sign in / Sign up

Export Citation Format

Share Document