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1

Investigation of silver nanoparticles embedded in extracted gelatins from camel, bovine, and fish bones for possible use in radiation dosimetry

Alrashidi Thaar K., Aljuhani Alwaleed, Almugaiteeb Faisal, Badi Nacer, Al-Aoh Hatem A., Alghamdi Saleh A., Alsharari Abdulrhman M, Alzahrani Ahmed Obaid M, Almalki Khaled

Materials Science Poland

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2023

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Vol. 41, No. 4

1--12

EN

Gelatins from camel, bovine, and fish bones were successfully extracted by using chemical pretreatment and heating methods. The bones were demineralized for 3 days at ambient temperature using hydrochloric acid solutions (0.5–1 M), and the collagen was partially hydrolyzed by preheating in distilled water at 75–80°C for 3 h, followed by extraction temperature at 90°C for 1 h. Free-standing films of gelatin entrained with silver nanoparticles (Gel/AgNPs) at low concentrations (1.25, 2.5, and 5 mM) were synthesized as radiation dosimeters. A high-energy ultrasonic homogenizer was used to dissolve the gelatin in distilled water and to disperse the AgNPs in the gelatin. The nanocomposites’ morphology and crystallinity were investigated using scanning electron microscopy (SEM), optical absorption, and Fourier transform infrared (FTIR) spectroscopies. Dose enhancement was assessed using X-ray irradiations with beam energies below and above silver K-edge. The beam was configured by setting the X-ray generator at 15, 25.5, and 35 kV potential and a beam current of 1 mA. An X-ray detector is used to detect the number of electrons after passing through Gel/AgNPs samples. The use of AgNPs embedded in gelatin caused the enhancement of X-ray radiation absorption, and the highest percentage of linearity for the dosimeter was found to be 90% in the optical range of 395 nm to 425 nm. The preliminary results demonstrated that Gel/AgNPs material may be used in radiation dosimetry for low-energy radiotherapy sources.

2

The assessment of temperature amplitude arising during the implant bed formation in relation to variable preparation parameters – in vitro study

Kosior Piotr, Nikodem Anna, Kozuń Marta, Dudek Krzysztof, Janeczek M., Dobrzyński Maciej

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 3

163--173

EN

The main purpose of this study was to analyse the temperatures generated during the bone bed preparation, given the internal structure of the bone bed, the geometry of the hole, and the treatment parameters such as the type of cooling and the rotational speed of the drill. The investigated material was domestic pig ribs, in which holes were drilled three times using two drill bit systems used for Hiossen® and Paltop® dental implantation. The ThermaCAM® P640 thermal imaging camera was used for measurement of drilling temperatures. After the holes were drilled, each rib was examined using the 1172 SkyScan microtomograph, Bruker®, to compare the geometry of the machined holes. The presented study proved that larger diameter drill bits (Hiossen® drill bits) generate more heat during the machining process, as evidenced by higher temperatures obtained for the Hiossen system in each case. It was proved that rotational speed, drill bit diameter and cooling system have a significant effect on the amount of heat generated during bone tissue preparation. The density and type of bone tissue in which the hole is prepared are significant factors affecting the amount of heat generated.

3

Experimental evaluation of a novel concept of an implant for direct skeletal attachment of limb prosthesis

Prochor Piotr

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 4

3--13

EN

Purpose: The aim of the study was to experimentally evaluate a proposed two-part implantation system (medullary part made of PEEK composite and percutaneous part made of Ti6Al4V) for bone-anchored prosthesis and to compare it to typical press-fit design (also made of Ti6Al4V) used for the same purpose. Methods: Simplified prototypes of both implants were prepared for the research. Both implants were evaluated in vitro with the use of porcine femur (6 bones for each implant). ARAMIS vision system was used to measure strains in selected area of bone shaft, generated when putting an axial load on the implants to simulate static load bearing exercises performed during rehabilitation activities in primary stabilisation. Results: Obtained maps revealed high concentrations of strains, located near to distal part of the implant, during using a typical press-fit design with relatively low strain around the implant’s shaft. In the case of proposed design, noticeable strains occurred in the entire examined area of bone, with stronger concentration towards the proximal direction. Conclusions: Presented experimental results suggest that proposed design provides more appropriate implant-bone load transfer than typically used press-fit design. This may result in obtaining more beneficial mechanobiological stimulus which enables the researchers to achieve appropriate primary stability and maintain appropriate bone quality during its long-term use after achieving full osseointegration.

4

A 3D trabecular bone homogenization technique

Marques Marco Costa, Belinha J., Oliveira A. F., Manzanares Cespedes M.C., Natal Jorge R.M.

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 3

139--152

EN

Purpose: Bone is a hierarchical material that can be characterized from the microscale to macroscale. Multiscale models make it possible to study bone remodeling, inducing bone adaptation by using information of bone multiple scales. This work proposes a computationally efficient homogenization methodology useful for multiscale analysis. This technique is capable to define the homogenized microscale mechanical properties of the trabecular bone highly heterogeneous medium. Methods: In this work, a morphology-based fabric tensor and a set of anisotropic phenomenological laws for bone tissue was used, in order to define the bone micro-scale mechanical properties. To validate the developed methodology, several examples were performed in order to analyze its numerical behavior. Thus, trabecular bone and fabricated benchmarks patches (representing special cases of trabecular bone morphologies) were analyzed under compression. Results: The results show that the developed technique is robust and capable to provide a consistent material homogenization, indicating that the homogeneous models were capable to accurately reproduce the micro-scale patch mechanical behavior. Conclusions: The developed method has shown to be robust, computationally less demanding and enabling the authors to obtain close results when comparing the heterogeneous models with equivalent homogenized models. Therefore, it is capable to accurately predict the micro-scale patch mechanical behavior in a fraction of the time required by classic homogenization techniques.

5

The influence of phase change material (PCM) on selected properties of polyurethane/magnetite systems

Lach Aleksandra, Pielichowska Kinga

Engineering of Biomaterials

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2019

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Vol. 22, no. 153 spec. iss.

95

6

Impact of ZrO2 additive on properties of PMMA-based bone cement

Laska-Leśniewicz Anna, Gaudyńska Marta, Gawlik Patrycja, Sobczyk-Guzenda Anna

Engineering of Biomaterials

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2019

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Vol. 22, no. 153 spec. iss.

69

7

Surface characterization of the raw and cooked bovine cortical metatarsal bone

Petrovic Bojan B., Kojic Sanja, Peric Tamara O., Šipovac Milica, Lazarevic Jovana, Stefanovic Sofija, Stojanovic Goran

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 1

13--21

EN

The purpose of this study was to quantify the elastic properties and evaluate microscopical features of raw and boiled metatarsal bovine bone. Methods: The elastic modulus, hardness and microscopic surface of raw and cooked bovine metatarsal bone have been investigated using nanoindentation, SEM/EDX and Panasis microscope. Results: Regarding raw bovine bone, the average elastic modulus was 30.515 ± 6,769 GPa, while the average hardness was 0.5683 ± 0.211 GPa. When it comes to boiled bone corresponding values were 22.298 ± 7.0303 GPa and 0.408 ± 0.199 GPa, respectively. The values for investigated parameters were significantly higher ( p < 0.05) in raw bone specimens. Elastic modulus significantly correlated with hardness ( p < 0.05). EDX analysis revealed significant decrease in wt% of oxygen in boiled samples ( p < 0.05) No significant differences could be observed in SEM images particularly when analysing in smaller magnifications. Using higher magnification, additional branching of the existing voids as well as discrete reorganization and smoother edges of nutrient canals could be observed. The surface of boiled specimens was without the presence of crusts and layering, and no microscopical evidence of structural damage could be observed. Conclusions: This study provides detailed analysis of hardness, elastic modulus of raw and cooked bovine bone and their relation and changes during exposure to temperature. These results of elastic moduli and hardness could be comparable to similar studies of bovine and human bone tissue, but the careful analysis of experimental design, type of the bone as well as limitations of the employed techniques must be carried out before interpolation of the results to other theoretical, clinical, biomaterial and archeological studies.

8

Temperature controlled dual hypoxic chamber design for in vitro ischemia experiments

Bagó M., Horváthy D. B., Simon M., Marschall B., Pinto A., Kuten O., Polsek D., Hornyák I., Nehrer S., Lacza Z.

Biocybernetics and Biomedical Engineering

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2018

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Vol. 38, no. 3

498--503

EN

In vitro ischemia models are designed to study various aspects of hypo-perfusion, focusing on the consequences of acute events under body temperature. Cold ischemia is less investigated even though the beneficial effects of cooling is expected. The aim of the present work was to develop a device modeling cold and warm ischemia in vitro. Oxygen-glucose deprivation was applied with continuous nitrogen flow and glucose-free cell culture media to mimic ischemia. The temperature in both chambers were independently set between 4 and 37 °C. Samples were placed inside for the ischemic period, followed by a reperfusion stage under standard cell culture conditions. We tested rat calvaria bone pieces undergoing 1, 7, 12 and 24 h of ischemia at 4 and 37 °C. After 24 h of reperfusion, cell number was measured with a tetrazolium cell viability assay. One hour of warm ischemia paradoxically increased the post-reperfusion cell count, while cold-ischemia had an opposite effect. After 7 h of warm ischemia the cells were already unable to recover, while under cold ischemia 60% of the cells were still functioning. After 12 h of cold ischemia 50% of the cells were still be able to recover, while at 24 h even the low temperature was unable to keep the cells alive. The markedly different effect of warm and cold ischemia suggests that this newly designed systemis capable of reliable and reproducible modeling of ischemic conditions. Moreover, it also enables deeper investigations in the pathophysiology of cold ischemia at cellular and tissue level.

9

Numerical analysis of the foods nature effect on the mechanical behavior of dental implants

Sifi M., Serier B., Merdji A., Benaissa A, Mootanah R.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 4

1021--1032

EN

This study focuses on a three-dimensional numerical analysis by the finite element method, the mechanical behavior of the dental prosthesis implant composed of a single implant. The effect of the nature of food on the level and distribution of the Von Mises equivalent stress generated in the bone and the elements that constitute this prosthesis have been highlighted. It has been shown that this level is particularly important that the Crushed masticated foods are rigid. This work was carried out to answer questions whose purpose was to analyze the risk of overload in the mandibular region. Loads transfer mechanisms and the possible failure of osseointegrated implants, the shape of the implant, the geometrical and mechanical properties of the placement site and bone resorption of the crest. A proper estimation of these effects allows the correct design of the implant.

10

Zjawiska elektryczne w kościach jako efekt piezoelektryczności hydroksyapatytu

Pawlikowski M.

Auxiliary Sciences in Archaeology, Preservation of Relics and Environmental Engineering

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2017

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nr 22

1--9

PL

Wykonane badania biomineralogiczne wskazują na piezoelektryczne właściwości apatytu, który jest jednym z głównych składników kości. Publikacja prezentuje hipotetyczne zależności między piezoelektrycznymi właściwościami apatytu kostnego i towarzyszącymi zjawiskami elektromagnetycznymi w kościach i ich otoczeniu. Zwraca uwagę na relacje – właściwości elektryczne kości – zmiany pola elektromagnetycznego wokół kości oraz na relacje zewnętrzne zmiany ciśnienia i in. – zjawiska elektryczne w kościach.

EN

Conducted biomineralogical studies indicate piezoelectric properties of apatite, which is one of the major components of bone. This publication presents hypothetical correlations between piezoelectric properties of bone apatite and the accompanying electromagnetic phenomena in bones and their environment. It notes the correlations between electrical properties of bones and changes in the electromagnetic field around bones, as well as connections between external pressure changes etc. and electrical phenomena in the bones.

11

Evaluation of functional and structural changes affecting the lumbar spine in professional field hockey players

Ogurkowska M. B., Kawałek K.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 2

51--58

EN

Purpose: The aim of this study was to evaluate functional and structural changes in the lumbar spine. Methods: The research group consisted of 20 male professional field hockey players. Computed tomography scans were collected to define the radiological density of the vertebral bodies and to calculate Young’s modulus. An electrogoniometer was used to measure the range of movement. Geometric parameters, such as Lumbar Lordosis Angle, Index of Lumbar Lordosis, Whitmann-Ferguson Angle and Anterior Pelvic Tilt, were also measured. Results: The values describing lumbar lordosis increased linearly with years of training and were significantly greater than those reported in the literature. Field hockey players displayed a larger range of flexion, side bending and rotation to the right. An analysis of radiological density found significantly high values. An analysis of Young’s modulus showed that the vertebral bodies become more fragile. Conclusions: The results show that overuse changes in the lumbar spine of field hockey players are severe and highly correlated with years of training.

12

Osteophyte development during osteoarthritis (OA) : consideration of angiogenesis, mechanical loading and tissue microstructure

Bednarczyk E., Lekszycki T.

Engineering Transactions

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2016

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Vol. 64, iss. 4

533--540

EN

This paper is devoted to modelling and investigation of the effects of mechanical loading, blood vessels development and tissue microstructure in osteoarthritis (OA) – a degenerative joint disease. OA is one of the most common diseases affecting the population, and therefore it is a social and medical problem of utmost importance. It predominantly affects the elderly but also sportsmen, obese people and those with curvature of the spine. Although the phenomenon of OA is not yet fully understood, it is commonly accepted that mechanical aspects are crucial in its evolution [1, 2]. Mechanical overloading leads to chondrocytes apoptosis which increases generation of vascular endothelial growth factors [3] then expansion of angiogenesis and osteophyte onset. A properly formulated mathematical model of cartilage degeneration and osteophytes development can significantly help in understanding the complexity of this process. The presented model reflects the most important aspects of the interactions between mechanical and biological factors, crucial for the phenomenon of OA.

13

Zastosowanie tokoferolu i kwasu acetylosalicylowego w ochronie tkanki kostnej przed skutkami doświadczalnego zatrucia 2,3,7,8-tetrachloro-dibenzo-p-dioksyną (TCDD)

Dobrzyński M., Bazan J., Gamian A, Rosińczuk-Tonderys J, Parulska O, Całkosiński I.

Rocznik Ochrona Środowiska

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2014

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Tom 16, cz. 1

300--322

EN

Dioxins are released into the environment as by-products of technological processes, i.a. in the chemical industry, pulp and paper industry, metallurgical industry, textile industry and dyeing industry. Dioxins are a group of compounds recognized by the International Agency for Research on Cancer (IARC) as carcinogens of Group A since 01/06/1997. The carcinogenic action has been demonstrated on animals. Despite stringent obligations arising from the provisions of The Stockholm Convention on Persistent Organic Pollutants on reducing POPs emissions to the environment (including dioxins) emission of these substances is still significant. These compounds often enter the food chain in random or intentional way and accumulate in organisms in the top of the food chain. This leads to the poisoning of the organism and appearance of clinical symptoms. According to the real hazard of poisoning the people, especially employed in the chemical industry, who are exposed to dioxins, research to determine the impact of these xenobiotics on various tissues and organs as well as to develop of effective pharmacological prevention is constantly conducted. Despite of the wide spectrum of the assessment of dioxins biological effects among humans and animals, there are only a few publications evaluating the impact of dioxins on the bone tissue. The main components of the fully functional bone are calcium phosphates and magnesium phosphates. From the proper saturation of bone matrix with salts of these chemical elements (mineralization) depends the hardness and elasticity of the bone. The young bone mineralization is controlled by a group of proteins, from which the most important is osteonectin, osteocalcin and alkaline phosphatase. Many xenobiotics, including dioxins, have a negative influence on the biosynthesis of these proteins. The measurement of calcium and magnesium concentration in bone is one of the methods for assessing bone destruction. The aim of this study was to investigate the effect of 2,3,7,8-tetrachlorodobenzo-p-dioxin (TCDD) in rats on calcium and magnesium levels in bone tissue of their offspring. Moreover the aim of this study was to check whether the administration of the dioxin receptor antagonists – tocopherol and acetylsalicylic acid – can reduce negative effects of dioxin action. Study was performed on 2-day newborns of Buffalo strain rats. Lower levels of calcium and magnesium was found both in cranial vault bones and the knee from newborns of mothers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. It was shown that administration of mothers exposed to 2,3,7,8- tetrachlorodibenzo-p-dioxin tocopherol or acetylsalicylic acid prevent decreases in calcium and magnesium concentrations in the bone tissue of the offspring.

14

Cost - Effective and Sufficiently Precise Integration Method Adapted to the FEM Calculations of Bone Tissue

Mazur K, Dąbrowski L.

Computational Methods in Science and Technology

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2014

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Vol. 20, No. 3

101--108

EN

The technique of Young’s modulus variation in the finite element is not spread in biomechanics. Our future goal is to adapt this technique to bone tissue strength calculations. The aim of this paper is to present the necessary studies of the element’s integration method that takes into account changes in material properties. For research purposes, a virtual sample with the size and distribution of mechanical properties similar to these in a human femoral wall, was used. WinPython, an environment of Python programming language was used to perform simulations. Results with the proposed element were compared with ANSYS element PLANE42 (with constant Young modulus). The modeled sample was calculated with five different integration methods at five different mesh densities. Considered integration methods showed a very high correlation of results. Two-point Gauss Quadrature Rule proved to be the most advantageous. Results obtained by this method deviate only slightly from the pattern, while the computing time was significantly lower than others. Performed studies have shown that accuracy of the solution depends largely on the mesh density of the sample. Application of the simplest integration method in combination with four times coarser mesh density than in ANSYS with a standard component still allowed to obtain better results.

15

Zastosowanie ultradźwięków w leczeniu uszkodzeń i odbudowie kości. przegląd piśmiennictwa

Kowal M., Pozowski A., Paprocka-Borowicz M., Kierzek A., Kuciel-Lewandowska J.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2014

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Vol. 20, nr 3

172--180

PL

Terapia ultradźwiękowa jest obecnie szeroko dostępna oraz stosowana w fizjoterapii i medycynie sportowej. Pulsacyjne ultradźwięki niskiej częstotliwości LIPUS (ang. low-intesity pulsed ultrasound) nie powodują zmian termicznych. Badania kliniczne, zgodne z medycyną opartą na faktach, potwierdziły możliwość ich zastosowania w procesie zrostu kostnego. Celem pracy jest przegląd obecnego stanu wiedzy na temat LIPUS. Do badań wykorzystano platformę Web of Knowledge. Używanym językiem był język angielski. Jako opcje wyszukiwania zostały użyte różne kombinacje słów kluczowych: LIPUS, bone, soft tissue, healing. Wyszukiwania zostały zawężone do publikacji z ostatnich 10 lat z włączoną lematyzacją. 10 prac zostało ocenionych pod kątem skuteczności randomizacji dla potrzeb medycyny opartej na faktach. Badania, głównie przedkliniczne, dowodzą przydatności stosowania LIPUS w przypadku opóźnionego zrostu kostnego lub jego braku. Jednakże niska wartość metodologiczna badań nad zwierzętami bądź liniami komórkowymi sugeruje potrzebę dalszego kontynuowania prac.

EN

The ultrasound therapy is now widely available and used in physiotherapy and sports medicine. The low-intensity pulsed ultrasound (LIPUS) does not cause any thermal reactions. Clinical examination, conducted in accordance with the evidence-based medicine, has confirmed its applicability in the process of bone healing. The purpose of the review is to review the current state of knowledge on LIPUS. Web of Knowledge platform was exploited. The language used was English. Different combinations of keywords were used as the search options: LIPUS, bone, soft tissue, healing. The exploration was restricted to the publications from the last 10 years and included lemmatization. 10 papers were evaluated in terms of results efficacy of randomization for the evidence-based medicine purposes. The examination, mainly preclinical, proved the usefulness of LIPUS in the case of delayed union or non-union of bone. However, the low value of methodological studies on animals or cell lines suggests the need for further continuation of the work.

16

Evaluation of PCL and PCL/n-HAp fibres processed by melt spinning

Rajzer I., Fabia J., Graczyk T., Piekarczyk W.

Engineering of Biomaterials

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2013

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Vol. 16, no. 118

2--4

EN

In this work the process for the manufacture of polycaprolactone fibres containing hydroxyapatite nanoparticles by melt spinning method was developed. The effect of nanohydroxyapatite content on the fibre structure and properties was investigated with FTIR, SEM, DSC, TGA methods. The mechanical properties of obtained fibres enable further processing to scaffolds by nonwoven technologies.

17

Method of Skeletal System Modelling

Olszewski H., Wojnicz W., Wittbrodt E.

Archive of Mechanical Engineering

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2013

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Vol. LX, nr 3

335--346

EN

An original method of skeletal system modelling is presented in detail. Using DICOM images obtained from CT and PET tests, shell models of nine bones were created (humerus, radius, ulna, scapula, clavicle, femur, tibia, fibula, pelvis). Two methods of bone behaviour are also proposed, the first method treating the bone as a solid structure and the second method treating the bone as a complex porous structure. The behaviour of model parts is numerically examined by using the finite element method.

PL

W artykule opisano autorską metodę modelowania układu szkieletowego. Stosując zdjęcia DICOM otrzymane z badania CT i PET, utworzono dziewięć modeli powłokowych kości (kości ramiennej, kości promieniowej, kości łokciowej, łopatki, obojczyka, kości udowej, kości piszczelowej, kości strzałkowej i miednicy). Zaproponowano dwie metody modelowania zachowania kości. Zgodnie z pierwsza metoda kość jest traktowana jako bryła jednorodna, zgodnie z druga metoda - jako złożona struktura porowata. Zachowanie składowych części modelu zostało numerycznie przebadane, stosując metodę elementów skończonych.

18

Ocena cytozgodnosci in vitro ceramicznych substytutów tkanki kostnej opartych na α-TCP

Noga M., Olkowski R., Lewandowska-Szumieł M., Siek D., Czechowska J., Zima A., Ślósarczyk A.

Engineering of Biomaterials

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2012

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Vol. 15, no. 116-117 spec. iss.

90--91

PL

Fosforany wapnia (CaPs) ze względu na ich mineralogiczne podobieństwo do nieorganicznego składnika kości oraz zdolność do tworzenia bezpośredniego wiązania z tkanką kostną stanowią obiecującą grupę biomateriałów kościozastępczych. W celu sprawdzenia cytozgodności potencjalnych materiałów implantacyjnych stosuje się wiele różnych testów analizujących zmiany w integralności błony komórkowej, aktywności enzymów związanych z metabolizmem komórki czy też zdolności do proliferacji. Pozytywny wynik cytozgodności in vitro pozwala na dopuszczenie materiału do dalszych badań in vivo. Celem niniejszej pracy była ocena cytozgodności in vitro cementów kostnych opartych na fosforanie wapnia w odmianie krystalograficznej а (α-TCP). Wykonano badania cytozgodności następujących materiałów ceramicznych typu cementowego oznaczonych jako: T-AP (na bazie α-TCP), TK-APi TK-CM (na bazie α-TCP i kalcytu) oraz AHT-M i CHMT-M (opartych na α-TCP i hydroksyapatycie dotowanym odpowiednio srebrem lub magnezem). Do badania cytotozgodności materiałów wykorzystano linię komórek MG-63. Komórki te posiadają fenotyp osteoblastów we wczesnej fazie różnicowania i stanowią model komórek kostnych w badaniach in vitro. Wszystkie rodzaje próbek zasiedlono komórkami MG-63, a po 48 godz. hodowli oznaczono aktywność metaboliczną komórek za pomocą testu XTT. Część próbek ceramicznych poddano przed zasiedleniem godzinnej preinkubacji w pożywce hodowlanej. Ponadto wykonano pomiar stężenia jonów wapnia w pożywce pobranej z hodowli komórek na próbkach ceramicznych oraz w pożywce, w której przez 24 godz. ekstrahowane były materiały. Komórki MG-63 hodowano w obecności wyciągów z materiałów ceramicznych o stężeniu 100% (pełen wyciąg), 50%, 25%, 12,5% i 0% (czysta pożywka hodowlana). Aktywność metaboliczną komórek zbadano po 24 i 48 godzinach hodowli za pomocą testu XTT. Komórki poddano także obserwacji mikroskopowej. Przeprowadzono ciągłą obserwację mikroskopową komórek w kontakcie z każdym z materiałów. Komórki wysiano do 48-studzienkowej płytki hodowlanej, a następnie w studzienkach umieszczono próbki ceramiczne i przez 72 godziny rejestrowano obraz w hodowli komórek. Materiały oznaczone jako T-AP, TK-AP, AHT-M, CHMT-M obniżały zawartość jonów wapniowych w pożywce hodowlanej. TK-CM nie zmieniał stężenia tych jonów w medium hodowlanym. Komórki MG-63 hodowane bezpośrednio na próbkach ceramicznych wykazały niską aktywność metaboliczną na wszystkich zbadanych materiałach. Jednak preinkubacja materiałów w pożywce hodowlanej częściowo poprawiła przeżywalność komórek. Aktywność metaboliczna komórek hodowanych na materiałach T-AP, TK-AP i TK-CM poddanych preinkubacji wzrosła kilkukrotnie w stosunku do nieinkubowanych materiałów. Wyciągi z badanych materiałów ceramicznych cechowały się wysoką cytozgodnością we wszystkich rozcieńczeniach badanych roztworów. Obserwacja w czasie rzeczywistym komórek MG- 63 hodowanych w obecności materiałów ceramicznych pokazała, że badane próbki nie miały negatywnego wpływu na zachowanie się i morfologię komórek. Cytozgodność wszystkich badanych materiałów w hodowli komórek z ekstraktami z próbek ceramicznych pokazała, iż obniżenie stężenia jonów wapnia w pożywce hodowlanej nie miało negatywnego wpływu na przeżywalność i zachowanie się komórek MG63. Niska aktywność metaboliczna komórek w hodowli w bezpośrednim kontakcie w porównaniu z obserwacją w czasie rzeczywistym może wynikać z mniejszej objętości pożywki hodowlanej, a przez to większej ekspozycji komórek na nierównowagę jonową w medium hodowlanym. Przeżywalność komórek in vitro w kontakcie z materiałami ceramicznymi była znamiennie wyższa w układach eksperymentalnych w większej objętości medium. Ponadto preinkubacja przebadanych próbek poprawiła aktywność metaboliczną komórek hodowanych na materiałach, co nasuwa możliwości optymalizacji warunków hodowli in vitro. Na podstawie wyników hodowli w bezpośrednim kontakcie z materiałami po wcześniejszej preinkubacji zauważono, że komórki hodowane na próbkach na bazie α-TCP oraz α-TCP i kalcytu charakteryzowały się większą przeżywalnością w porównaniu z komórkami wysianymi na materiałach opartych na α-TCP i hydroksyapatycie.

EN

Due to their mineralogical similarity to the inorganic component of bone and the ability to bond with bone tissue phosphates of calcium (CaPs) are a promising group of bone substitutes. In order to investigate cytocompatibility of potential implant materials there are a wide range of tests analyzing changes in cell membrane integrity, activity of enzymes associated with cell metabolism or the ability of cells to proliferation. A positive outcome of in vitro cytocompatibility allows to perform in vivo study of tested materials. The aim of this work was to evaluate in vitro cytocompatibility of bone cements based on calcium phosphate with a crystal structure (α-TCP). Cytocompatibility of the following cement materials has been tested: T-AP (based on α-TCP), TK-AP, TK-CM (based on α-TCP-calcite) AHT-M, CHMT-M (based on α-TCP and hydroxyapatite with addition of silver or magnesium) MG-63 cell line has been used to investigate cytotoxicity of ceramics. MG-63 is human osteosarcoma cell line with phenotype of osteoblasts at an early stage of differentiation. All types of ceramic materials were seeded with MG-63 cells and after 48h of in vitro culture metabolic activity has been tested with XTT test. Some ceramic samples were also pre-incubated for 1 hour in the culture medium before seeding. In addition, media from culture and extracts from ceramics were collected and calcium ion concentration was measured. MG63 cells were cultured with different concentrations of ceramic extracts (100% - complete extract, 50%, 25%, 12,5%, 0% - pure medium). After 24 and 48h metabolic activity of cells has been investigated with XTT test. Cells were also observed in light microscopy. To investigate influence of ceramic materials on MG-63 cells continuous microscopic observation was performed. Cells were seeded into 48-well culture plates, then ceramic samples have been placed into wells and photos of wells were captured during 72 hours long cell culture. Materials designated as T-AP, TK-AP, AHT-M and CHMT-M diminished calcium ion concentration in the culture medium, while TK-CM did not alter the calcium concentration. MG-63 cells cultured directly on samples exhibited low metabolic activity in all cases. Pre-incubation of materials in the medium partially enhanced cell survival. Extracts made of the examined materials are characterized by high cytocompatibility in all dilutions of tested solutions. Real-time observation of MG-63 cells cultured in the presence of ceramic materials did not reveal any negative impact of the samples on cell behavior and morphology. We observed the difference between the results of cytotoxicity tests performed on direct and indirect contact in vitro culture. Cytocompatibility of extracts made of the tested ceramics showed that decreasing of the calcium ion concentration in the culture medium did not have negative influence on survival and the behavior of MG63 cells. Lower metabolic activity of cells cultured directly on materials in comparison with the real-time observation of culture may be due to a smaller volume of culture medium, and thus greater exposure of cells to an ionic imbalance in the culture medium. Cell survival in contact with the ceramic materials was significantly higher in the experimental system with a larger volume of medium. In addition, preincubation of tested samples improved the metabolic activity of cells cultured on the materials. Positive effect of sample pre-incubation in medium enables the possibility to optimize the culture conditions in vitro. The results of culture on the preincubated materials showed that cells seeded on the samples based on α-TCP and α-TCP and calcite exhibited higher survival compared to cells cultured on materials based on α-TCP and hydroxyapatite.

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Zmiany własności mechanicznych kości zwierzęcych w zależności od stopnia nawilżenia preparatu

Sadowska J., Kromka-Szydek M.

Aktualne Problemy Biomechaniki

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2012

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z. 6

111--116

20

Geometrical aspects of growth plate modelling using Carter's and Stokes's approaches

Piszczatowski Sz.

Acta of Bioengineering and Biomechanics

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2012

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Vol. 14, no. 1

93-106

EN

Development of the skeleton is a complex mechanobiological process. Shape and size of the majority of bone elements are the result of endochondral growth and ossification occurring during childhood and adolescent period. The influence of mechanical loading acting in the skeletal system on bone development is known since the 19th century, but understanding of such phenomenon seems to be still insufficient. Traditionally accepted Hueter-Volkmann law claims that increased pressure acting on a growth plate retards bone growth and, conversely, reduced pressure or even tension accelerates it. Stokes's approach is directly based on this theory. Carter's model seems to be slightly more complex because takes into account three-dimensional stress state. The subject of the research was to evaluate the mechanobiological condition of endochondral bone growth occurring within the growth cartilage where different geometrical structures (8 models) of the growth plate and various loading conditions (5 variants) were considered. Simulations were made using the finite element method and both Stokes's and Carter's models were used to estimate mechanical stimulation of bone growth. Results indicate non-uniformity of the growth conditions occurring within the growth cartilage when its layer is located between two bone blocks. Non-axial loadings result in dissymmetry of mechanical stimulation of bone growth. In general, its minimum is located in the regions of the cartilage to which maximal loadings were directed. Carter's approach is, however, more sensitive to interrelation between growth plate geometrical structure and loading direction, compared to Stokes's model. Obtained results indicate the necessity of realistic modelling of the growing bone geometrical structure, including the elaboration of custom-made models. Further research is necessary to elaborate the new formula describing mechanical influences on bone growth, taking into account the cyclic loading of a constant direction. In this way it will be possible to overcome the still existing problems with the explanation of numerous clinical phenomena.