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1.
Sensors (Basel) ; 21(11)2021 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-34200076

RESUMO

In light of the growth in demand for multiband antennas for medical applications, this research proposes a MICS/ISM meander-line microstrip antenna encapsulated in an oblong-shaped pod for use in diagnoses of the gastrointestinal tract. The proposed antenna is operable in the Medical Implant Communication System (MICS) and the Industrial, Scientific and Medical (ISM) bands. The antenna structure consists of a meander-line radiating patch, a flipped-L defected ground plane, and a loading resistor for antenna miniaturization. The MICS/ISM microstrip antenna encapsulated in an oblong-shaped pod was simulated in various lossy-material environments. In addition, the specific absorption rate (SAR) was calculated and compared against the IEEE C95.1 standard. For verification, an antenna prototype was fabricated and experiments carried out in equivalent liquid mixtures, the dielectric constants of which resembled human tissue. The measured impedance bandwidths (|S11| ≤ -10 dB) for the MICS and ISM bands were 398-407 MHz and 2.41-2.48 GHz. The measured antenna gains were -38 dBi and -13 dBi, with a quasi-omnidirectional radiation pattern. The measured SAR was substantially below the maximum safety limits. As a result, the described MICS/ISM microstrip antenna encapsulated in an oblong-shaped pod can be used for real-time gastrointestinal tract diagnosis. The novelty of this work lies in the use of a meander-line microstrip, flipped-L defected ground plane, and loading resistor to miniaturize the antenna and realize the MICS and ISM bands.


Assuntos
Próteses e Implantes , Tecnologia sem Fio , Desenho de Equipamento , Trato Gastrointestinal , Humanos , Miniaturização
2.
Mater Sci Eng C Mater Biol Appl ; 127: 112216, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225868

RESUMO

Additive manufacturing (AM) is recently imposing as a fast, reliable, and highly flexible solution to process various materials, that range from metals to polymers, to achieve a broad variety of customized end-goods without involving the injection molding process. The employment of biomaterials is of utmost relevance as the environmental footprint of the process and, consequently, of the end-goods is significantly decreased. Additive manufacturing can provide, in particular, an all-in-one platform to fabricate complex-shaped biobased items such as bone implants or biomedical devices, that would be, otherwise, extremely troublesome and costly to achieve. Polyhydroxyalkanoates (PHAs) is an emerging class of biobased and biodegradable polymeric materials achievable by fermentation from bacteria. There are some promising scientific and technical reports on the manufacturing of several commodities in PHAs by additive manufacturing. However, many challenges must still be faced in order to expand further the use of PHAs. In this framework, the present work reviews and classifies the relevant papers focused on the design and development of PHAs for different 3D printing techniques and overviews the most recent applications of this approach.


Assuntos
Poli-Hidroxialcanoatos , Materiais Biocompatíveis , Biopolímeros , Impressão Tridimensional , Próteses e Implantes
3.
Mater Sci Eng C Mater Biol Appl ; 127: 112241, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225881

RESUMO

Orthopedic implant is commonly associated with occurrence or relapse of osteomyelitis. This study developed a hydrofluoric acid (HF) cleaned silicon nitride (Si3N4) implant Si3N4_AC for osteomyelitis control and established a rat tibial osteomyelitis model to evaluate its efficacy on eradicating periprosthetic infection and enhancing bone regeneration. In vitro studies revealed Si3N4_AC had improved biocompatibility and inhibited Staphylococcus aureus adhesion. A custom-made Si3N4_AC implant was prepared and inserted into the rat tibia longitudinal cavity inoculated with Staphylococcus aureus. The in vivo bacteriostatic and osteogenic efficacies of Si3N4_AC implant were evaluated by histological, microbiological and Micro-CT analyses and compared with implants of pure Ti and Si3N4 . Si3N4_AC implant group revealed 99.5% inhibition of periprosthetic Staphylococcus aureus compared to the osteomyelitis group after 14 days post-operation. Implant-adhering bacteria density of Si3N4_AC was also much lower than pure Ti and Si3N4. In addition, micro-CT evaluation of peri-implant bone formation under the condition of periprosthetic osteomyelitis after 30 days post-surgery confirmed the osteogenic ability of Si3N4_AC. Taken together, Si3N4_AC can be an effective orthopedic biomaterial to eradicate periprosthetic infection and enhance bone regeneration.


Assuntos
Osteomielite , Infecções Estafilocócicas , Animais , Antibacterianos/farmacologia , Regeneração Óssea , Modelos Animais de Doenças , Ácido Fluorídrico , Osteomielite/tratamento farmacológico , Próteses e Implantes , Ratos , Compostos de Silício/farmacologia , Infecções Estafilocócicas/tratamento farmacológico
4.
Mater Sci Eng C Mater Biol Appl ; 127: 112247, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225886

RESUMO

The osteogenic activity of medical metal can be improved by lowering its surface stiffness and elastic modulus. However, it is very difficult to directly reduce the elastic modulus of medical metal surfaces. In this paper, with selected parameters, the titanium surface was treated via femtosecond laser irradiation. Micro indentation revealed that the femtosecond laser ablation can effectively reduce the surface Young's modulus and Vickers hardness of titanium. Besides, In order to explain the mechanical properties of degradation of titanium surface, Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) was used to simulate the process of laser ablation process of titanium surface, and it was found that after the ablation of titanium surface, voids were produced in the subsurface layer. The simulation showed that the voids are formed by the cavitation of metastable liquid induced by high tensile stress and high temperature during femtosecond laser irradiation. Subsurface voids with a thickness of about 40 nm were observed under the oxide layer in the experiment. Cell experiments showed that the surface with low Young's modulus was more conducive to cell proliferation and osteogenic differentiation.


Assuntos
Nanoporos , Osteogênese , Lasers , Próteses e Implantes , Propriedades de Superfície , Titânio
5.
Mater Sci Eng C Mater Biol Appl ; 127: 112250, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225889

RESUMO

Customized spinal implants fabricated by additive manufacturing have been increasingly used clinically to restore the physiological functions. However, the mechanisms and methods about the design for the spinal implants are not clear, especially for the reconstruction of multi-segment vertebral. This study aims to develop a novel multi-objective optimization methodology based on various normal spinal activities, to design the artificial vertebral implant (AVI) with lightweight, high-strength and high-stability. The biomechanical performance for two types of AVI was analyzed and compared under different loading conditions by finite element method. These implants were manufactured via selective laser melting technology and evaluated via compressive testing. Results showed the maximum Mises stress of the optimized implant under various load cases were about 41.5% of that of the trussed implant, and below fatigue strength of 3D printed titanium materials. The optimized implant was about 2 times to trussed implant in term of the maximum compression load and compression stiffness to per unit mass, which indicated the optimized implant can meet the safety requirement. Finally, the optimized implant has been used in clinical practice and good short-term clinical outcomes were achieved. Therefore, the novel developed method provides a favorable guarantee for the design of 3D printed multi-segment artificial vertebral implants.


Assuntos
Próteses e Implantes , Titânio , Fenômenos Biomecânicos , Análise de Elementos Finitos , Lasers , Impressão Tridimensional , Estresse Mecânico
6.
Mater Sci Eng C Mater Biol Appl ; 127: 112251, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225890

RESUMO

A variety of novel biomaterials are emerging as alternatives to conventional metals and alloys, for use in spinal implants. These promise potential advantages with respect to e.g. elastic modulus compatibility with the host bone, improved radiological imaging or enhanced cellular response to facilitate osseointegration. However, to date there is scarce comparative data on the biological response to many of these biomaterials that would give insights into the relative level of bone formation, resorption inhibition and inflammation. Thus, in this study, we aimed to evaluate and compare the in vitro biological response to standard discs of four alternative biomaterials: polyether ether ketone (PEEK), zirconia toughened alumina (ZTA), silicon nitride (SN) and surface-textured silicon nitride (ST-SN), and the reference titanium alloy Ti6Al4V (TI). Material-specific characteristics of these biomaterials were evaluated, such as surface roughness, wettability, protein adsorption (BSA) and apatite forming capacity in simulated body fluid. The activity of pre-osteoblasts seeded on the discs was characterized, by measuring viability, proliferation, attachment and morphology. Then, the osteogenic differentiation of pre-osteoblasts was compared in vitro from early to late stage by Alizarin Red S staining and real-time PCR analysis. Finally, osteoclast activity and inflammatory response were assessed by real-time PCR analysis. Compared to TI, all other materials generally demonstrated a lower osteoclastic activity and inflammatory response. ZTA and SN showed generally an enhanced osteogenic differentiation and actin length. Overall, we could show that SN and ST-SN showed a higher osteogenic effect than the other reference groups, an inhibitive effect against bone resorption and low inflammation, and the results indicate that silicon nitride has a promising potential to be developed further for spinal implants that require enhanced osseointegration.


Assuntos
Materiais Biocompatíveis , Osteogênese , Materiais Biocompatíveis/farmacologia , Teste de Materiais , Osseointegração , Osteoblastos , Próteses e Implantes , Propriedades de Superfície , Titânio
7.
Sensors (Basel) ; 21(13)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202554

RESUMO

LoRa is a long-range and low-power radio technology largely employed in Internet of Things (IoT) scenarios. It defines the lower physical layer while other protocols, such as LoRaWAN, define the upper layers of the network. A LoRaWAN network assumes a star topology where each of the nodes communicates with multiple gateways which, in turn, forward the collected data to a network server. The main LoRaWAN characteristic is the central role of the gateways; however, in some application scenarios, a much lighter protocol stack, relying only on node capabilities and without the presence of gateways, can be more suitable. In this paper, we present a preliminary study for realizing a LoRa-based mesh network, not relying on LoRaWAN, that implements a peer-to-peer communication between nodes, without the use of gateways, and extends node reachability through multi-hop communication. To validate our investigations, we present a hardware/software prototype based on low-power-consumption devices, and we preliminarily assess the proposed solution.


Assuntos
Telas Cirúrgicas , Tecnologia sem Fio , Comunicação , Próteses e Implantes
8.
J Int Med Res ; 49(7): 3000605211025347, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34212773

RESUMO

OBJECTIVE: To evaluate the short-term effectiveness of using a three-dimensional (3D)-printed custom-made prosthesis to repair unicondylar femoral defects. METHODS: We retrospectively reviewed 26 patients with a primary pathological fracture of the distal femur caused by a giant cell tumor. All patients had unicondylar defects involving the articular surface. Twelve patients were treated with a 3D-printed custom-made prosthesis to repair the unicondylar defect (3D-printed group). The other 14 patients were treated with total knee replacement (TKR group). The operation time, blood loss, Musculoskeletal Tumor Society score, range of motion, local recurrence, and complications were statistically compared. RESULTS: The operation time was significantly shorter and the blood loss was significantly less in the 3D-printed group than in the TKR group. The Musculoskeletal Tumor Society scores were significantly higher in the 3D-printed group than in the TKR group from 3 to 24 months postoperatively. The range of motion was significantly better in the 3D-printed group than in the TKR group at 6 and 9 months postoperatively. CONCLUSIONS: 3D-printed custom-made prostheses provide better short-term functional results than does TKR.


Assuntos
Neoplasias Ósseas , Fraturas Espontâneas , Tumores de Células Gigantes , Fêmur/diagnóstico por imagem , Fêmur/cirurgia , Humanos , Recidiva Local de Neoplasia , Impressão Tridimensional , Próteses e Implantes , Estudos Retrospectivos , Resultado do Tratamento
9.
Artigo em Inglês | MEDLINE | ID: mdl-34200143

RESUMO

The aim of this human cadaver study was to assess the accuracy of zygomatic/pterygoid implant placement using custom-made bone-supported laser sintered titanium templates. For this purpose, pre-surgical planning was done on computed tomography scans of each cadaver. Surgical guides were printed using direct metal laser sintering technology. Four zygomatic and two pterygoid implants were inserted in each case using the guided protocol and related tools. Post-operative computed tomography (CT) scans were obtained to evaluate deviations between the planned and inserted implants. Accuracy was measured by overlaying the real position in the post-operative CT on the virtual presurgical placement of the implant in a CT image. Descriptive and bivariate analyses of the data were performed. As a result, a total of 40 zygomatic and 20 pterygoid implants were inserted in 10 cadavers. The mean deviations between the planned and the placed zygomatic and pterygoid implants were respectively (mean ± SD): 1.69° ± 1.12° and 4.15° ± 3.53° for angular deviation. Linear distance deviations: 0.93 mm ± 1.23 mm and 1.35 mm ± 1.45 mm at platform depth, 1.35 mm ± 0.78 mm and 1.81 mm ± 1.47 mm at apical plane, 1.07 mm ± 1.47 mm and 1.22 mm ± 1.44 mm for apical depth. In conclusion, the surgical guide system showed accuracy for all the variables studied and allowed acceptable and accurate implant placement regardless of the case complexity.


Assuntos
Cirurgia Assistida por Computador , Cadáver , Desenho Assistido por Computador , Humanos , Próteses e Implantes , Tomografia Computadorizada por Raios X
10.
Molecules ; 26(11)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34074062

RESUMO

The goal of the work was to develop materials dedicated to spine surgery that minimized the potential for infection originating from the transfer of bacteria during long surgeries. The bacteria form biofilms, causing implant loosening, pain and finally, a risk of paralysis for patients. Our strategy focused both on improvement of antibacterial properties against bacteria adhesion and on wear and corrosion resistance of tools for spine surgery. Further, a ~35% decrease in implant and tool dimensions was expected by introducing ultrahigh-strength titanium alloys for less-invasive surgeries. The tested materials, in the form of thin, multi-layered coatings, showed nanocrystalline microstructures. Performed direct-cytotoxicity studies (including lactate dehydrogenase activity measurement) showed that there was a low probability of adverse effects on surrounding SAOS-2 (Homo sapiens bone osteosarcoma) cells. The microbiological studies (e.g., ISO 22196 contact tests) showed that implanting Ag nanoparticles into Ti/TixN coatings inhibited the growth of E. coli and S. aureus cells and reduced their adhesion to the material surface. These findings suggest that Ag-nanoparticles present in implant coatings may potentially minimize infection risk and lower inherent stress.


Assuntos
Ligas/farmacologia , Antibacterianos/farmacologia , Próteses e Implantes , Coluna Vertebral/cirurgia , Titânio/farmacologia , Humanos
11.
Nat Commun ; 12(1): 3757, 2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-34145249

RESUMO

Peptides are widely used for surface modification to develop improved implants, such as cell adhesion RGD peptide and antimicrobial peptide (AMP). However, it is a daunting challenge to identify an optimized condition with the two peptides showing their intended activities and the parameters for reaching such a condition. Herein, we develop a high-throughput strategy, preparing titanium (Ti) surfaces with a gradient in peptide density by click reaction as a platform, to screen the positions with desired functions. Such positions are corresponding to optimized molecular parameters (peptide densities/ratios) and associated preparation parameters (reaction times/reactant concentrations). These parameters are then extracted to prepare nongradient mono- and dual-peptide functionalized Ti surfaces with desired biocompatibility or/and antimicrobial activity in vitro and in vivo. We also demonstrate this strategy could be extended to other materials. Here, we show that the high-throughput versatile strategy holds great promise for rational design and preparation of functional biomaterial surfaces.


Assuntos
Materiais Revestidos Biocompatíveis/química , Próteses e Implantes/microbiologia , Titânio/química , Animais , Adesão Celular/fisiologia , Células Cultivadas , Ensaios de Triagem em Larga Escala , Camundongos , Coelhos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Propriedades de Superfície
12.
Nat Commun ; 12(1): 3710, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-34140475

RESUMO

The growing need for the implementation of stretchable biosensors in the body has driven rapid prototyping schemes through the direct ink writing of multidimensional functional architectures. Recent approaches employ biocompatible inks that are dispensable through an automated nozzle injection system. However, their application in medical practices remains challenged in reliable recording due to their viscoelastic nature that yields mechanical and electrical hysteresis under periodic large strains. Herein, we report sponge-like poroelastic silicone composites adaptable for high-precision direct writing of custom-designed stretchable biosensors, which are soft and insensitive to strains. Their unique structural properties yield a robust coupling to living tissues, enabling high-fidelity recording of spatiotemporal electrophysiological activity and real-time ultrasound imaging for visual feedback. In vivo evaluations of custom-fit biosensors in a murine acute myocardial infarction model demonstrate a potential clinical utility in the simultaneous intraoperative recording and imaging on the epicardium, which may guide definitive surgical treatments.


Assuntos
Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Diagnóstico por Imagem/métodos , Infarto do Miocárdio/diagnóstico por imagem , Pericárdio/diagnóstico por imagem , Animais , Materiais Biocompatíveis/química , Linhagem Celular , Modelos Animais de Doenças , Eletrocardiografia , Fenômenos Eletrofisiológicos , Processamento de Imagem Assistida por Computador , Tinta , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Simulação de Dinâmica Molecular , Mioblastos/metabolismo , Mioblastos/patologia , Próteses e Implantes , Silicones/química , Análise Espaço-Temporal , Suínos , Ultrassonografia
16.
J Clin Neurosci ; 89: 237-242, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34119274

RESUMO

The SpineJack implant system was recently FDA approved for treatment of vertebral compression fractures (VCF), however United States-based outcomes data is lacking. We sought to examine the safety and clinical outcomes following vertebral augmentation using the SpineJack implant for treatment of VCF in a U.S. patient population. An IRB-approved, retrospective study of SpineJack implants used in vertebral augmentation was performed from 11/2018 to 2/2020. Outcome objectives included pain improvement, vertebral body height (VH) restoration, improvement in local kyphotic angle (LKA), and incidence of adjacent level fractures (ALF). Complications were reviewed to assess safety of the procedure. Thirty patients with VCF (60% female; mean [SD] age of 62.7 [±12.8] years) underwent a total of 53 vertebral augmentations with 106 SpineJack implants. Worst pain scores decreased significantly from 8.7 to 4.3 (95%CI of the change [Δ]: 4.3-4.4; p < 0.001). Middle and anterior VH significantly increased from 13.1 ± 0.2 to 15.9 ± 0.2 mm (95%CI Δ: 2.6-2.9 mm; p < 0.001) and 15.6 ± 0.2 to 16.8 ± 0.2 mm (95%CI Δ: 1.1-1.4 mm; p < 0.001), respectively. LKA was significantly decreased from 10.0 ± 2.1 to 7.4 ± 2.1 degrees (95%CI Δ: 2.4-2.8 degrees; p < 0.001). Four patients (13%) sustained ten ALF over a median (IQR) follow up period of 94 (17.5-203) days. There were no major adverse events during the follow up period. To summarize, vertebral augmentation with SpineJack implants of patients with VCF resulted in significantly decreased pain, restored VH, and improved LKA, without major adverse events. However, 13% of patients sustained ALF during a median follow up period of 3 months.


Assuntos
Fraturas por Compressão/epidemiologia , Fraturas por Compressão/cirurgia , Fixadores Internos/tendências , Vigilância da População , Fraturas da Coluna Vertebral/epidemiologia , Fraturas da Coluna Vertebral/cirurgia , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Fraturas por Compressão/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Fraturas por Osteoporose/diagnóstico por imagem , Fraturas por Osteoporose/epidemiologia , Fraturas por Osteoporose/cirurgia , Dor/diagnóstico por imagem , Dor/epidemiologia , Dor/cirurgia , Próteses e Implantes/tendências , Estudos Retrospectivos , Fraturas da Coluna Vertebral/diagnóstico por imagem , Resultado do Tratamento , Estados Unidos/epidemiologia
17.
Bone ; 151: 116032, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34118446

RESUMO

Mechanical environment has a crucial role in our organism at the different levels, ranging from cells to tissues and our own organs. This regulatory role is especially relevant for bones, given their importance as load-transmitting elements that allow the movement of our body as well as the protection of vital organs from load impacts. Therefore bone, as living tissue, is continuously adapting its properties, shape and repairing itself, being the mechanical loads one of the main regulatory stimuli that modulate this adaptive behavior. Here we review some key results of bone mechanobiology from computational models, describing the effect that changes associated to the mechanical environment induce in bone response, implant design and scaffold-driven bone regeneration.


Assuntos
Regeneração Óssea , Osso e Ossos , Biofísica , Próteses e Implantes
18.
Sensors (Basel) ; 21(9)2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-34063000

RESUMO

Decision-making is an important part of human life and particularly in any engineering process related to a complex product. New sensors and actuators based on MEMS technologies are increasingly complex and quickly evolving into products. New biomedical implanted devices may benefit from system engineering approaches, previously reserved to very large projects, and it is expected that this need will increase in the future. Here, we propose the application of Model Based Systems Engineering (MBSE) to systematize and optimize the trade-off analysis process. The criteria, their utility functions and the weighting factors are applied in a systematic way for the selection of the best alternative. Combining trade-off with MBSE allow us to identify the more suitable technology to be implemented to transfer energy to an implanted biomedical micro device.


Assuntos
Sistemas de Liberação de Medicamentos , Próteses e Implantes , Engenharia Biomédica , Engenharia , Humanos , Tecnologia sem Fio
19.
Sensors (Basel) ; 21(9)2021 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-34063296

RESUMO

Implantable antennas are mandatory to transfer data from implants to the external world wirelessly. Smart implants can be used to monitor and diagnose the medical conditions of the patient. The dispersion of the dielectric constant of the tissues and variability of organ structures of the human body absorb most of the antenna radiation. Consequently, implanting an antenna inside the human body is a very challenging task. The design of the antenna is required to fulfill several conditions, such as miniaturization of the antenna dimension, biocompatibility, the satisfaction of the Specific Absorption Rate (SAR), and efficient radiation characteristics. The asymmetric hostile human body environment makes implant antenna technology even more challenging. This paper aims to summarize the recent implantable antenna technologies for medical applications and highlight the major research challenges. Also, it highlights the required technology and the frequency band, and the factors that can affect the radio frequency propagation through human body tissue. It includes a demonstration of a parametric literature investigation of the implantable antennas developed. Furthermore, fabrication and implantation methods of the antenna inside the human body are summarized elaborately. This extensive summary of the medical implantable antenna technology will help in understanding the prospects and challenges of this technology.


Assuntos
Próteses e Implantes , Ondas de Rádio , Humanos , Miniaturização , Tecnologia sem Fio
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