Improving the Mechanical Resistance of Hydroxyapatite/Chitosan Composite Materials Made of Nanofibers with Crystalline Preferential Orientation

Abstract

The stability and mechanical properties of hydroxyapatite (HAp)/Chitosan composite materials depend on the dispersion of HAp aggregates in the chitosan matrix and on the chemical interaction between them. Therefore, hexagonal cross-sectioned HAp nanofibers were produced using a microwave-assisted hydrothermal method. Glutamic acid was used to control the HAp crystal growth; thereby, nanofibers were obtained with a preferential crystalline orientation, and they were grown along the “c” axis of HAp crystal structures. This morphology exposed the (300) and (100) crystal planes on the surface, and several phosphate groups and calcium ions were also exposed; they were able to form numerous chemical interactions with the amine, hydroxyl, and carbonyl groups of chitosan. Consequently, the final mechanical resistance of the composite materials was synergistically increased. Nanofibers were mixed with commercial chitosan using a sonotrode to improve their dispersion within the biopolymer matrix and prevent migration. The HAp nanofiber/Chitosan composite materials showed higher mechanical resistance than that observed in similar materials with the same chemical composition that were made of commercial HAp powders, which were used as reference materials. The mechanical resistance under tension of the composite materials made of nanofibers was similar to that reported for cortical bone.

Complex Evaluation of Nanocomposite-Based Hydroxyapatite for Biomedical Applications

“…The -CH2 -bending vibration (from the chitosan structure) was found at 1424 cm −1 [46][47][48][49]. Furthermore, the 1639 and 1456 cm −1 maxima are indicating the presence of amide I (C=O) and amino (NH2) groups from the chitosan structure in the MgHApC sample [46][47][48][49][50]. According to the studies conducted by Chatterjee N.S.…”

“…Furthermore, in Figure 12, the second derivative spectra obtained for the MgHApC sample are presented in the 1400-1800 cm −1 spectral domain. Herein could be noticed the presence of the bands that may be associated with the -CH 2 -bending vibration (around 1424 cm −1 ), amino (around 1456 cm −1 ), amide II (around 1549 cm −1 ), and amide I (around 1639 cm −1 ), groups from chitosan [46][47][48][49][50].…”

Altering Microbiomes with Hydroxyapatite Nanoparticles: A Metagenomic Analysis

“…Hydroxyapatite (HAp, Ca 5 (PO 4 ) 3 OH) is the most abundant inorganic material in the mammalian bodies, where it forms hard tissues, including bone, enamel, dentin and cementum, but also other organs, including tusks in animals such as elephants or narwhals, horns in deer, moose, elks and caribous, and the shell-like osteoderm of armadillos [ 16 ]. Despite being one of the oldest biomaterials in research and clinical application, HAp continues to attract the attention of researchers to this day, and new studies on it do not abate [ 17 , 18 , 19 ]. Recently, our group demonstrated that HAp displays finite antibacterial properties, which appear to become intensified when the bacterial species are converted from regular lab strains to clinical, multidrug-resistant ones [ 20 , 21 , 22 ].…”