Role of Interfacial Interactions on Mechanical Properties of Biomimetic Composites for Bone Tissue Engineering

2005 ◽  
Vol 898 ◽  
Author(s):  
Devendra Verma ◽  
Rahul Bhowmik ◽  
Bedabibhas Mohanty ◽  
Dinesh R Katti ◽  
Kalpana S Katti

AbstractInterfaces play an important role in controlling the mechanical properties of composites. Optimum mechanical strength of scaffolds is of prime importance for bone tissue engineering. In the present work, molecular dynamics simulations and experimental studies have been conducted to study effect of interfacial interactions on mechanical properties of composites for bone replacement. In order to mimic biological processes, hydroxyapatite (HAP) is mineralized in presence of polyacrylic acid (PAAc) (in situ HAP). Further, solid and porous composites of in situ HAP with polycaprolactone (PCL) are made. Mechanical tests of composites of in situ HAP with PAAc have shown improved strain recovery, higher modulus/density ratio and also improved mechanical response in simulated body fluid (SBF). Simulation studies indicate potential for calcium bridging between –COO− of PAAc and surface calcium of HAP. This fact is also supported by infrared spectroscopic studies. PAAc modified surfaces of in situ HAP offer means to control the microstructure and mechanical response of porous composites. Nanoindentation experiments indicate that apatite grown on in situ HAP/PCL composites from SBF has improved elastic modulus and hardness. This work gives insight into the interfacial mechanisms responsible for mechanical response as well as bioactivity in biomaterials.

2004 ◽  
Vol 844 ◽  
Author(s):  
Devendra Verma ◽  
Kalpana S. Katti ◽  
Bedabibhas Mohanty

ABSTRACTA biomimetic process involving in situ mineralization of hydroxyapatite (HAP) is used to design new composite biomaterials for bone tissue engineering. Surface and bulk properties of HAP composites have been studied for hydroxyapatite mineralized in absence (ex situ) of polyacrylic acid (PAAc) and in presence (in situ) of PAAc. XRD studies show existence of structural disorder within in situ HAP. It has been observed that PAAc increases the rate of crystallization. FTIR studies indicate calcium deficiency in structure of both in situ and ex situ HAP. PAAc provides favorable sites for nucleation of HAP. During crystallization of HAP, PAAc dissociates to form carboxylate ion, which binds to HAP. Porous and solid composites of in situ and ex situ HAP with polycaprolactone (PCL) in 50:50 ratio have been made to evaluate their applicability as bone scaffold. Mechanical tests on solid samples indicate ex situ HAP/PCL composites have higher elastic modulus (1.16 GPa) than in situ HAP/PCL composites (0.82 GPa). However, in case of porous composites, in situ HAP/PCL composites are found to have higher elastic modulus (29.5 MPa) than ex situ HAP/PCL composites (10.4 MPa). Nanoindentation tests were also performed at different loads to evaluate mechanical properties of the composites. In situ HAP mineralized using non-degradable polymers has thus been shown to improve mechanical response in porous composites.


Author(s):  
Kalpana S. Katti ◽  
Devendra Verma ◽  
Rahul Bhowmik ◽  
Dinesh R. Katti

Achieving optimal mechanical strength of scaffolds is the key issue in bone tissue engineering. We describe a biomimetic route for design of composites of polymers (polyacrylic acid (PAAc) and polycaprolactone (PCL)) and hydroxyapatite (HAP). The mineral polymer interfaces have a significant role on mechanical behavior as well as bioactivity of the composite systems. We have used a combination of experimental (photoacoustic infrared spectroscopy) as well as modeling (molecular dynamics) techniques to evaluate the nature of interfaces in the composites. Porous composite scaffolds of in situ HAP with PCL are made. Our simulation studies indicate calcium bridging between COO− of PAAc and surface calcium of HAP as well as hydrogen bonding. These results are also supported by infrared spectroscopic studies. PAAc modified surfaces of in situ HAP influence the microstructure and mechanical response of porous composites. Significant differences are present in the mechanical response of in situ and ex situ composite scaffolds. In addition, the growth and mechanism of apatite growth in the in situ and ex situ composites is different. Bioactivity is measured by soaking composite scaffolds in simulated body fluid (SBF). Apatite growth in ex situ composites is primarily by heterogeneous nucleation and that in in situ is primarily by homogeneous nucleation. We also observe that apatite grown on in situ HAP/PCL composites from SBF exhibits higher elastic modulus and hardness. Thus, by influencing the interfacial behavior in bone biomaterials both mechanical response and bioactivity of the composite systems may be modified. The present study gives insight into the interfacial mechanisms responsible for mechanical response as well as bioactivity in biomaterials.


Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 287
Author(s):  
Ye Lin Park ◽  
Kiwon Park ◽  
Jae Min Cha

Over the past decades, a number of bone tissue engineering (BTE) approaches have been developed to address substantial challenges in the management of critical size bone defects. Although the majority of BTE strategies developed in the laboratory have been limited due to lack of clinical relevance in translation, primary prerequisites for the construction of vascularized functional bone grafts have gained confidence owing to the accumulated knowledge of the osteogenic, osteoinductive, and osteoconductive properties of mesenchymal stem cells and bone-relevant biomaterials that reflect bone-healing mechanisms. In this review, we summarize the current knowledge of bone-healing mechanisms focusing on the details that should be embodied in the development of vascularized BTE, and discuss promising strategies based on 3D-bioprinting technologies that efficiently coalesce the abovementioned main features in bone-healing systems, which comprehensively interact during the bone regeneration processes.


Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1319
Author(s):  
Muhammad Umar Aslam Khan ◽  
Wafa Shamsan Al-Arjan ◽  
Mona Saad Binkadem ◽  
Hassan Mehboob ◽  
Adnan Haider ◽  
...  

Bone tissue engineering is an advanced field for treatment of fractured bones to restore/regulate biological functions. Biopolymeric/bioceramic-based hybrid nanocomposite scaffolds are potential biomaterials for bone tissue because of biodegradable and biocompatible characteristics. We report synthesis of nanocomposite based on acrylic acid (AAc)/guar gum (GG), nano-hydroxyapatite (HAp NPs), titanium nanoparticles (TiO2 NPs), and optimum graphene oxide (GO) amount via free radical polymerization method. Porous scaffolds were fabricated through freeze-drying technique and coated with silver sulphadiazine. Different techniques were used to investigate functional group, crystal structural properties, morphology/elemental properties, porosity, and mechanical properties of fabricated scaffolds. Results show that increasing amount of TiO2 in combination with optimized GO has improved physicochemical and microstructural properties, mechanical properties (compressive strength (2.96 to 13.31 MPa) and Young’s modulus (39.56 to 300.81 MPa)), and porous properties (pore size (256.11 to 107.42 μm) and porosity (79.97 to 44.32%)). After 150 min, silver sulfadiazine release was found to be ~94.1%. In vitro assay of scaffolds also exhibited promising results against mouse pre-osteoblast (MC3T3-E1) cell lines. Hence, these fabricated scaffolds would be potential biomaterials for bone tissue engineering in biomedical engineering.


2015 ◽  
Vol 3 (23) ◽  
pp. 4679-4689 ◽  
Author(s):  
Ya-Ping Guo ◽  
Jun-Jie Guan ◽  
Jun Yang ◽  
Yang Wang ◽  
Chang-Qing Zhang ◽  
...  

A bioinspired strategy has been developed to fabricate a hybrid nanostructured hydroxyapatite–chitosan composite scaffold for bone tissue engineering.


2011 ◽  
Vol 5 (2) ◽  
pp. 104-111 ◽  
Author(s):  
Isabel B. Leonor ◽  
Márcia T. Rodrigues ◽  
Manuela E. Gomes ◽  
Rui L. Reis

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yong-Seok Jang ◽  
Phonelavanh Manivong ◽  
Yu-Kyoung Kim ◽  
Kyung-Seon Kim ◽  
Sook-Jeong Lee ◽  
...  

Beta-tricalcium phosphate bioceramics are widely used as bone replacement scaffolds in bone tissue engineering. The purpose of this study is to develop beta-tricalcium phosphate scaffold with the optimum mechanical properties and porosity and to identify the effect of N-acetyl-L-cysteine loaded to beta-tricalcium phosphate scaffold on the enhancement of biocompatibility. The various interconnected porous scaffolds were fabricated using slurries containing various concentrations of beta-tricalcium phosphate and different coating times by replica method using polyurethane foam as a passing material. It was confirmed that the scaffold of 40 w/v% beta-tricalcium phosphate with three coating times had optimum microstructure and mechanical properties for bone tissue engineering application. The various concentration of N-acetyl-L-cysteine was loaded on 40 w/v% beta-tricalcium phosphate scaffold. Scaffold group loaded 5 mM N-acetyl-L-cysteine showed the best viability of MC3T3-E1 preosteoblastic cells in the water-soluble tetrazolium salt assay test.


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