Body Implants Research Articles

Relationship between Body Fat Percentages by Bioelectrical Impedance Analysis and Body Mass Index (BMI) And other metabolic Parameters among Filipino Adults At Emilio Aguinaldo College Medical Center- Cavite

Background: Obesity posing burgeoning risk for mortality, diabetes mellitus, cardiovascular diseases and cancer among fast ageing Filipino population must be accurately measured by the use of rapid, non-invasive, digitally precise tool, Body Fat percentage and segmental body composition obesity predictors in Bioelectrical Impedance Analysis where overseas studies established significant but limited results. Our study focused on Filipino group with the correlation of its body fat percentage and other obesity predictors set in BIA therein like Free Fat Mass, Fat, Bone and Muscle masses, visceral fat amongst others, with Body Mass Index and other conventional obesity measurements.
 Method: This cross-sectional, correlational study included 363 Filipinos, patients and employees of Emilio Aguinaldo College Medical Center- Cavite and nearby health center, 18-80 years of age, BMI of 16-34, excluded those pregnant and bearing metallic body implants, have imparted their History, level of activity. Installed Standardized protocol for Physical Examination, measurements of height, weight, Body mass index waist and hip circumferences, waist-hip ratio, systolic blood pressure and diastolic blood pressure.
 Results: All BIA measurements used Tanita MC980. The Pearson correlation coefficients, Binary logistic regression analysis, two tailed test, Shapiro-Wilk tests analyzed 137 Males, 226 females with mean age of 34.64, p-value of 0.29, showed strong, significant correlation between BFP and BMI, and other measurements, where BMI had strongest correlation to women than men with synonymous correlation with other metabolic variables and predictors, and no significant difference between genders.
 Conclusion: Our research reflected that Body Fat Percentage have strong significant correlation with BMI, metabolic variables and obesity predictors measured, established a better estimate for obesity as compared to the conventional measurements.

Rapid Functionalization of Polytetrafluorethylene (PTFE) Surfaces with Nitrogen Functional Groups.

The biocompatibility of body implants made from polytetrafluoroethylene (PTFE) is inadequate; therefore, the surface should be grafted with biocompatible molecules. Because PTFE is an inert polymer, the adhesion of the biocompatible film may not be appropriate. Therefore, the PFTE surface should be modified to enable better adhesion, preferably by functionalization with amino groups. A two-step process for functionalization of PTFE surface is described. The first step employs inductively coupled hydrogen plasma in the H-mode and the second ammonia plasma. The evolution of functional groups upon treatment with ammonia plasma in different modes is presented. The surface is saturated with nitrogen groups within a second if ammonia plasma is sustained in the H-mode at the pressure of 35 Pa and forward power of 200 W. The nitrogen-rich surface film persists for several seconds, while prolonged treatment causes etching. The etching is suppressed but not eliminated using pulsed ammonia plasma at 35 Pa and 200 W. Ammonia plasma in the E-mode at the same pressure, but forward power of 25 W, causes more gradual functionalization and etching was not observed even at prolonged treatments up to 100 s. Detailed investigation of the XPS spectra enabled revealing the surface kinetics for all three cases.

A Critical Review on Effect of Process Parameters on Mechanical and Microstructural Properties of Powder-Bed Fusion Additive Manufacturing of SS316L.

Additive manufacturing (AM) is one of the recently studied research areas, due to its ability to eliminate different subtractive manufacturing limitations, such as difficultly in fabricating complex parts, material wastage, and numbers of sequential operations. Laser-powder bed fusion (L-PBF) AM for SS316L is known for complex part production due to layer-by-layer deposition and is extensively used in the aerospace, automobile, and medical sectors. The process parameter selection is crucial for deciding the overall quality of the SS316L build component with L-PBF AM. This review critically elaborates the effect of various input parameters, i.e., laser power, scanning speed, hatch spacing, and layer thickness, on various mechanical properties of AM SS316L, such as tensile strength, hardness, and the effect of porosity, along with the microstructure evolution. The effect of other AM parameters, such as the build orientation, pre-heating temperature, and particle size, on the build properties is also discussed. The scope of this review also concerns the challenges in practical applications of AM SS316L. Hence, the residual stress formation, their influence on the mechanical properties and corrosion behavior of the AM build part for bio implant application is also considered. This review involves a detailed comparison of properties achievable with different AM techniques and various post-processing techniques, such as heat treatment and grain refinement effects on properties. This review would help in selecting suitable process parameters for various human body implants and many different applications. This study would also help to better understand the effect of each process parameter of PBF-AM on the SS316L build part quality.

Bio Glasses and glass-ceramics: Properties, Preparation, and Clinical application

Ceramics and glasses are not the same as metals, despite being near relatives. Both have excellent strength, hardness, elastic modulus, and chemical inertness and are electrical and thermal insulators. Glasses are amorphous, whereas ceramics are crystalline. These glasses are being utilized as implants in the human body to mend and replace damaged or diseased bones due to their biocompatibility and bioactivity. Because they encourage new bone formation both along with the bone-implant contact and within the implant distant from the bone-implant interface, bioactive glasses are osteoconductive and osteoinductive materials.

Role of vitamin C in the protection of the gum and implants in the human body: theoretical and experimental studies

Role of vitamin C in the protection of the gum and implants in the human body: theoretical and experimental studies

Electrochemical corrosion response of ZrN coated Nickel-Titanium alloy in 0.9% NaCl solution

Abstract: The biomedical application as metallic body implants of Nickel-Titanium shape memory alloys are of high interest due to its unique property of pseudo elasticity. However, high content of nickel and its potential to release from the surface due to corrosion raises safety concerns about its allergic reactions, toxicity and carcinogenicity. Hence, it is necessary to produce proper passivity to prevent surface layer degradation. In this study, ZrN coating on Nickel-Titanium shape memory alloys was obtained by vacuum cathodic arc physical vapor deposition technique to improve electrochemical corrosion resistance. The electrochemical corrosion response was studied in 0.9% NaCl solution at 370C using Tafel extrapolation method. Surface morphology was studied using SEM/EDAX and XRD. ZrN coating increases corrosion stability and micro hardness. Keywords: Shape memory alloy; pseudoelasticity; vacuum cathodic arc PVD; electrochemical corrosion; micro hardness.

Implant Fibrosis and the Underappreciated Role of Myofibroblasts in the Foreign Body Reaction.

Body implants and implantable medical devices have dramatically improved and prolonged the life of countless patients. However, our body repair mechanisms have evolved to isolate, reject, or destroy any object that is recognized as foreign to the organism and inevitably mounts a foreign body reaction (FBR). Depending on its severity and chronicity, the FBR can impair implant performance or create severe clinical complications that will require surgical removal and/or replacement of the faulty device. The number of review articles discussing the FBR seems to be proportional to the number of different implant materials and clinical applications and one wonders, what else is there to tell? We will here take the position of a fibrosis researcher (which, coincidentally, we are) to elaborate similarities and differences between the FBR, normal wound healing, and chronic healing conditions that result in the development of peri-implant fibrosis. After giving credit to macrophages in the inflammatory phase of the FBR, we will mainly focus on the activation of fibroblastic cells into matrix-producing and highly contractile myofibroblasts. While fibrosis has been discussed to be a consequence of the disturbed and chronic inflammatory milieu in the FBR, direct activation of myofibroblasts at the implant surface is less commonly considered. Thus, we will provide a perspective how physical properties of the implant surface control myofibroblast actions and accumulation of stiff scar tissue. Because formation of scar tissue at the surface and around implant materials is a major reason for device failure and extraction surgeries, providing implant surfaces with myofibroblast-suppressing features is a first step to enhance implant acceptance and functional lifetime. Alternative therapeutic targets are elements of the myofibroblast mechanotransduction and contractile machinery and we will end with a brief overview on such targets that are considered for the treatment of other organ fibroses.

Preparation and Performance Evaluation of Duotone 3D-Printed Polyetheretherketone as Oral Prosthetic Materials: A Proof-of-Concept Study.

Literature has reported the successful use of 3D printed polyetheretherketone (PEEK) to fabricate human body implants and oral prostheses. However, the current 3D printed PEEK (brown color) cannot mimic the vivid color of oral tissues and thus cannot meet the esthetical need for dental application. Therefore, titanium dioxide (TiO2) and ferric oxide (Fe2O3) were incorporated into PEEK to prepare a series of tooth-color and gingival-color PEEK composites in this study. Through color measurements and mechanical tests, the color value and mechanical performance of the 3D printed PEEK composites were evaluated. In addition, duotone PEEK specimens were printed by a double nozzle with an interface between tooth-color and gingival-color parts. The mechanical performance of duotone PEEK with two different interfaces (horizontal and vertical) was investigated. With the addition of TiO2 and Fe2O3, the colors of 3D printed PEEK composites become closer to that of dental shade guides. 3D printed PEEK composites generally demonstrated superior tensile and flexural properties and hence have great potential in the dental application. In addition, duotone 3D printed PEEK with a horizontal interfacial orientation presented better mechanical performance than that with a vertical one.

Synergistic regulation mechanism of bionic structure and poly (vinylsulfonic acid) sodium (PVSNa) coating for high load bearing lubrication

A low friction coefficient and high bearing capacity can improve the service life of implants in the human body. In this study, the surface performance was improved by coupling the structure with the material. The bionic structure was obtained on the titanium alloy (Ti6Al4V) surface by chemical etching. The mechanical properties of Ti6Al4V with bionic structure were investigated by tribological experiments with different stresses. An interesting phenomenon was found that the friction coefficient of etched surface decreased with the increase of the stress, indicating that bionic structure can effectively improve the stability of Ti6Al4V surface bearing capacity. A poly (vinylsulfonic acid) sodium (PVSNa) coating was further fabricated on etched Ti6Al4V to obtain low friction. During the sliding process, PVSNA molecules were continuously added from the bionic structure to the surface through friction force for lubrication. The synergistic regulation of bionic structure and PVSNa coating made Ti6Al4V surface obtain low friction and high bearing capacity stability. This study can serve as a guide for the design of low friction and high bearing capacity stability.

125I Intracavitary Irradiation Combined with 125I Seeds Implantation for Treatment of Locally Advanced Pancreatic Head Cancer: A Retrospective Analysis of 67 Cases.

BackgroundPancreatic cancer is an aggressive malignant tumor of the digestive system and the fourth leading cause of tumor-related death. Intracavitary 125I seed irradiation has been recently developed as a therapy for locally advanced pancreatic head carcinoma. However, there are still many limitations, and more investigations are needed in order to optimize this new treatment method.MethodsSixty-seven patients were included in our study; 41 cases treated by SEMS-CL-125I intracavular irradiation (SEMS-CL-125I group) and 26 cases treated by SEMS-CL-125I intracavular irradiation combined with 125I particle implantation in the tumor body (the combined group). Among the 67 patients, 43 were males and 24 were females, with an average age of 69.64±8.84 years. Tumor site size was determined based on the MRI or CT imaging scans, and the number and radius of 125I particle placement were calculated according to a specific formula. 125I particles were inserted into the tumor with a radius of 1.5 cm and a row spacing of 1 cm. The main postoperative biochemical indexes, imaging analysis, postoperative analgesia degree, median survival time and rate of complications were compared between the two groups.ResultsJaundice and liver function improved in both groups after treatment for 6 months. The combined group did better. Kaplan–Meier analysis showed that patients in the combined group had a significantly better overall survival than those in the SEMS-CL-125I group. Patients in the combined group had less complications than those in the SEMS-CL-125I group (23.1% vs 34.1%), and the postoperative pain status of the combined group was improved (26.8% vs 53.8%).ConclusionCompared with the SEMS-CL-125I intracavular irradiation alone, the combination of 125I seed implantation with solid tumor 125I seed implantation had a better therapeutic effect in LAPHC patients, with improved biochemical indicators, survival prognosis, pain relief, and fewer complications.

Applications of 3D Bio-Printing in Tissue Engineering and Biomedicine.

In recent years, 3D bio-printing technology has developed rapidly and become an advanced bio-manufacturing technology. At present, 3D bio-printing technology has been explored in the fields of tissue engineering, drug testing and screening, regenerative medicine and clinical disease research and has achieved many research results. Among them, the application of 3D bio-printing technology in tissue engineering has been widely concerned by researchers, and it contributing many breakthroughs in the preparation of tissue engineering scaffolds. In the future, it is possible to print fully functional tissues or organs by using 3D bio-printing technology which exhibiting great potential development prospects in th applications of organ transplantation and human body implants. It is expected to solve thebiomedical problems of organ shortage and repair of damaged tissues and organs. Besides,3Dbio-printing technology will benefit human beings in more fields. Therefore, this paper reviews the current applications, research progresses and limitations of 3D bio-printing technology in biomedical and life sciences, and discusses the main printing strategies of 3D bio-printing technology. And, the research emphases, possible development trends and suggestions of the application of 3D bio-printing are summarized to provide references for the application research of 3D bio-printing.

Investigation of porous cells interface on elastic property of orthopedic implants: Numerical and experimental studies

Application of porous cells in orthopedic implants makes it possible to better approximation of elastic property of human bones. Although the mechanical and biological properties of orthopedic porous implants are studied in many researches, the interaction between different porous unit cells from geometrical compatibility and also, considering manufacturing conditions for the ultimate goal of bone ingrowth is not thoroughly investigated. In this study, a kelvin cell is designed with 530 to 810 μm pore sizes, which is the appropriate range for bone ingrowth. Due to anatomical position of implants in the human body and the limited range of the elastic modulus of kelvin cell with different geometrical parameters, this unit cell is combined with other cells to extend the range of its elastic modulus. After selecting the appropriate combination of cells to achieve desired properties, they are fabricated with Stainless Steel 316 L using radially gradient porosity in the range of 64% to 80%, and then finite element method (FEM) is performed to evaluate the elastic modulus, stress distribution, and strain energy of the proposed structures. Gradient and uniform structures are fabricated using selective laser melting (SLM) to validate FEM results. The simulation and experimental results are close to each other with an average error of about 4.5%. The elastic modulus derived from FEM for the designed gradient structures are in the range of 7.48 to 10.49 GPa, which can be modified, and present mechanical properties close to trabecular or compact bone based on the position and conditions of the bone defect.

Suppression mechanism of initial pitting corrosion of pure Zn by Li alloying

Localized corrosion makes Zn vulnerable to unpredictable fracture under stress loading, resulting in mechanical failure when used as implants in human body. This study reveals that 0.8 wt.% Li alloying suppresses pitting corrosion of Zn significantly in simulated body fluid, resulting in 290 times less of localized corrosion volume after immersion for 30 days. A corrosion layer with two sub-layers forms on the alloy surface. The 10-nm-thick inner layer consists of amorphous Li2O/LiOH and ZnO/Zn(OH)2, while the 55-nm-thick outer sub-layer consists of Li2CO3 polycrystals, which is very effective to suppress pitting corrosion by blocking chloride ion penetration.

Silk: history, obtaining, structure and properties of an old material in the development of new technologies

The silk produced in the Bombyx mori’ glands and used in the preparation of the cocoons has been employed in the textile industry millennia ago in fabric production. These cocoons are composed mainly of fibroin (SF, Silk Fibroin), a fibrous protein that presents unique mechanical properties, in addition to being a biocompatible, biodegradable and low-cost source. This protein can be extracted from these cocoons by being processed in aqueous medium and used to obtain the most diverse materials for different applications, such as biomaterials development as body implants and in the composition of the scaffolds for tissue engineering, moreover to photonic devices as sensors, waveguides and lasers.

A Review on Bio-Composite Materials

Composite material constitute of different materials to have better characteristics than traditional materials. Material properties such as physical, chemical and mechanical properties can be tailored in composite material based on requirements. This advantage extends the composite material applications in the field of human implants. Traditional metals or ceramics have certain limitations after the implantation in human body, because of its inheriting properties with biological tissue. These limitations can be eradicated by the composite material; it makes composites to fabricate implant for biomedical applications. The new research works enhance the composite materials to mimic the natural bone, biological functions and tissue characteristics. Human tissue and bone are naturally graded from the core side, functionally graded material (FGM) implant overcome some limitations of composite materials. FGM implants elastic modulus can be tailored as like a composite material, its biological functions similar with natural one. Other biological parameters such as corrosion, wear resistance and fracture toughness are considered when designing the implant. This article discusses composite material advantage and limitations of both composite and FGM implants.

Dual 3D printing for vascularized bone tissue regeneration

The development of sufficient vascular networks is crucial for the successful fabrication of tissue constructs for regenerative medicine, as vascularization is essential to perform the metabolic functions of tissues, such as nutrient transportation and waste removal. In recent years, efforts to 3D print vascularized bone have gained substantial attention, as bone disorders and defects have a marked impact on the older generations of society. However, conventional and previous 3D printed bone studies have been plagued by the difficulty in obtaining the nanoscale geometrical precision necessary to recapitulate the distinct characteristics of natural bone. Additionally, the process of developing truly biomimetic vascularized bone tissue has been historically complex. In this study, a biomimetic nano-bone tissue construct with a perfusable, endothelialized vessel channel was developed using a combination of simple stereolithography (SLA) and fused deposition modeling (FDM) 3D printing systems. The perfusable vessel channel was created within the SLA printed bone scaffold using an FDM printed polyvinyl alcohol (PVA) sacrificial template. Within the fabricated constructs, bone tissue was formed through the osteogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs), and distinct capillaries sprouted through the angiogenesis of the endothelialized vessel channel after human umbilical vein endothelial cells (HUVECs) had been perfused throughout. Furthermore, the fabricated constructs were evaluated in physiologically relevant culture conditions to predict tissue development after implantation in the human body. The experimental results revealed that the custom-designed bioreactor with an hMSC-HUVEC co-culture system enhanced the formation of vascular networks and the osteogenic maturation of the constructs for up to 20 days of observation.

Synergistic Regulation Mechanism of Inorganic Thermal Oxidation Coating and Poly (Vinylphosphonic Acid) (PVPA) Coating for High Load Bearing Superlubricity

A low friction coefficient and high bearing capacity can improve the service life of implants in the human body. In this study, we firstly investigate the mechanical properties of inorganic thermal oxide coatings on titanium alloy (Ti6Al4V). Tribological experiments were performed for different tribo-pairs under uniform conditions. The inorganic thermal oxide coating on Ti6Al4V formed at 300℃ was found to have excellent tribological properties and can effectively improve the bearing capacity of Ti6Al4V. The organic poly (vinylphosphonic acid) (PVPA) on Ti6Al4V has excellent anti-friction properties, which can help achieve superlubricity. An inorganic thermal oxide/organic PVPA composite coating was fabricated on Ti6Al4V to obtain a surface with low friction and high bearing capacity. It is found that the presence of the thermal oxide doubled the bearing capacity of the composite coating compared to that of the PVPA coating alone. This study can serve as a guide for the modification of artificial joints.

Implementation of a fully implantable middle-ear hearing device chip.

BACKGROUND AND OBJECTIVE:Recently, with the increase in the population of hearing impaired people, various types of hearing aids have been rapidly developed. In particular, a fully implantable middle ear hearing device (F-IMEHD) is developed for people with sensorineural hearing loss. The F-IMEHD system comprises an implantable microphone, a transducer, and a signal processor. The signal processor should have a small size and consume less power for implantation in a human body.METHODS:In this study, we designed and fabricated a signal-processing chip using the modified FFT algorithm. This algorithm was developed focusing on eliminating time delay and system complexity in the transform process. The designed signal-processing chip comprises a 4-channel WDRC, a fitting memory, a communication 1control part, and a pulse density modulator. Each channel is separated using a 64-point fast Fourier transform (FFT) method and the gain value is matched using the fitting table in the fitting memory.RESULTS AND CONCLUSION: The chip was designed by Verilog-HDL and the designed HDL codes were verified by Modelsim-PE 10.3 (Mentor graphics, USA). The chip was fabricated using a 0.18 m CMOS process (SMIC, China). Experiments were performed on a cadaver to verify the performance of the fabricated chip.

Martensitic transformation in a α + β–Ti alloy after cryogenic treatment and its influencing to low elastic modulus biomaterials

The high strength titanium alloy is one of the most popular α + β-Ti type alloy and well responsive to the microstructure mainly depends on the processing history, heat treatment and selective faster cooling treatments. It has many engineering applications like military application, biomedical implant and aerospace application. The cryogenic treatment (CT) was typically done for faster cooling at low temperature (−20 to −100 °C) after solution treatment at 860 °C for 1 h then immediately quenched into liquid nitrogen bath with control manner. Subsequently, another identical sample quenched into the water to cool room temperature. After successfully solution treated both samples again preferred for ageing treatment at 500 °C for 5 h then air cooling. The examination of microstructures by SEM analysis revealed that after double steps heat treatment shows very fine α and β phases, with needle shape α are decomposed from α′ martensite tend to speed up by TiN or VN precipitates enhanced strength in the matrix. As well as, vanadium content is one of the important factors for martensite formation after solution treatment in the α + β phase field. The results show that after double steps heat treatment in CT obtained optimum mechanical properties such as 0.2% proof strength (PS) of 790 MPa, ultimate tensile strength (UTS) of 1200 MPa, strain (ε) of 70%, reduction area (RA) of 16.76%, and PS to UTS ratio of 0.66, respectively. To intuitive study estimate the effect in water quenching (WQ) as well as cryogenic treatment on microstructures and mechanical properties of high strength Ti-Al-V ternary alloy, which is potentially used in aerospace and structural applications owing to a high specific strength and high corrosion resistance. Meanwhile, after faster cooling in CT that martensite transformation tends to exhibit low elastic modulus for beneficial to orthopaedic implants in the human body.

Potential use of minimum quantity lubrication (MQL) in machining of biocompatible materials using environment friendly cutting fluids: An overview

Use of cutting fluids during machining is necessary as it not only removes the heat produced during the shearing of the work piece but also provides lubrication at the interface of chip and tool. Flood lubrication is the most generally used method of supplying cutting fluid in metal cutting industries where a large continuous stream of cutting fluid at the rate of 10–12 l/min at low pressure is supplied to the cutting zone. Most of cutting fluids when disposed to the environment cause serious environmental problems. From the view point of these ecological problems along with the concern regarding the operator’s health and an increased associated machining cost, there have been enormous efforts to restrict the application of the cutting fluids. In this regard dry cutting may seem a viable alternative but it is not found suitable especially for hard cutting materials like Titanium alloys and Nickel based super alloys which are used extensively in manufacturing of body implants. In this paper minimum quantity lubrication method is reviewed to find whether it can be used as viable alternative to conventional cutting fluid supplying methods in the manufacturing of bio-implants where a considerably higher surface integrity is desired in the finished component.