A comparative study of thermal calcination and an alkaline hydrolysis method in the isolation of hydroxyapatite from Thunnus obesus bone

Sustainable double-synergistic silver-hydroxyapatite composite catalyst derived from fish bones for efficient disinfection of Vibrio parahaemolyticus

Vibrio parahaemolyticus is a food-borne pathogen that poses a serious threat to seafood safety and human health. An efficient, nontoxic, and sustainable disinfection material with a stable structure is urgently needed. Herein, silver (Ag)-hydroxyapatite (HAP) composite catalysts were prepared using HAP derived from waste fish bones. The Ag2.50%-HAP showed a 100% disinfection rate against V. parahaemolyticus, disinfecting nearly 7.0 lg CFU mL-1 within 15 min at a low concentration of 300 μg mL-1. This efficient disinfection activity could be attributed to the double-synergistic effect of Ag and superoxide radicals, which resulted in the destruction of bacterial cell structures and the leakage of intracellular proteins. Importantly, the composite also exhibited high activity in controlling the growth of pathogens during the storage process of Penaeus vannamei. These findings provided sustainable composite catalysts for disinfecting V. parahaemolyticus in seafood and a high-value utilization strategy for waste fish bones.

Hydroxyapatite synthesis and characterization from waste animal bones and natural sources for biomedical applications

Hydroxyapatites (HAps) synthesized from waste animal bones have recently gained attention due to their outstanding properties. This is because there is a need to fabricate scaffolds with desirable mechanical strength, ability to withstand high temperatures, and insoluble in solvents such as water, acetone, ethanol, and isopropyl alcohol. This study is an extensive summary of many articles on the routes of synthesis/preparation of HAp, and the optimum processing parameter, and the biomedical application areas, such as: drug administration, dental implants, bone tissue engineering, orthopedic implant coatings, and tissue regeneration/wound healing. A broad catalog of the synthesis methods (and combination methods), temperature/time, shape/size, and the calcium-to-phosphorous (Ca/P) value of diverse waste animal bone sources were reported. The alkaline hydrolysis method is proposed to be suitable for synthesizing HAp from natural sources due to the technique's ability to produce intrinsic HAp. The method is also preferred to the calcination method owing to the phase transformation that takes place at high temperatures during calcinations. However, calcinations aid in removing impurities and germs during heating at high temperatures. When compared to calcination technique, alkaline hydrolysis method results in crystalline HAp; the higher degree of crystallinity is disadvantageous to HAp bioactivity. In addition, the standardization and removal of impurities and contaminants, thorough biocompatibility to ensure clinical safety of the HAp to the human body, and improvement of the mechanical strength and toughness to match specific requirements for the various biomedical applications are the important areas for future studies.

A novel Chilean salmon fish backbone-based nanoHydroxyApatite functional biomaterial for potential use in bone tissue engineering

Introduction

Given the ensuing increase in bone and periodontal diseases and defects, de novo bone repair and/or regeneration strategies are constantly undergoing-development alongside advances in orthopedic, oro-dental and cranio-maxillo-facial technologies and improvements in bio-/nano-materials. Indeed, there is a remarkably growing need for new oro-dental functional biomaterials that can help recreate soft and hard tissues and restore function and aesthetics of teeth/ dentition and surrounding tissues. In bone tissue engineering, HydroxyApatite minerals (HAp), the most stable CaP/Calcium Phosphate bioceramic and a widely-used material as a bone graft substitute, have been extensively studied for regenerative medicine and dentistry applications, including clinical use. Yet, limitations and challenges owing principally to its bio-mechanical strength, exist and therefore, research and innovation efforts continue to pursue enhancing its bio-effects, particularly at the nano-scale.

Methods

Herein, we report on the physico-chemical properties of a novel nanoHydroxyApatite material obtained from the backbone of Salmon fish (patent-pending); an abundant and promising yet under-explored alternative HAp source. Briefly, our nanoS-HAp obtained via a modified and innovative alkaline hydrolysis-calcination process was characterized by X-ray diffraction, electron microscopy, spectroscopy, and a cell viability assay.

Results and Discussion

When compared to control HAp (synthetic, human, bovine or porcine), our nanoS-HAp demonstrated attractive characteristics, a promising biomaterial candidate for use in bone tissue engineering, and beyond.

Synthesis of nano-hydroxyapatite using emulsion, pyrolysis, combustion, and sonochemical methods and biogenic sources: a review

Hydroxyapatite (HAp) is comparable to materials in bone because its chemical components are similar to those contained in animal bone, and thus, its bioactive and biocompatible properties are similar. There are applications for HAp and relevant calcium phosphate in the medical and industrial sectors, and due to the rising demand for HAp nanoparticles, considerable work has been performed to develop a variety of synthetic pathways that incorporate scientifically and practically novel aspects. Numerous studies have been conducted to examine how changes in reaction parameters will successfully influence crucial HAp features. HAp can also be synthesized from biogenic sources such as HAp-rich fish scales or animal bones as an alternative to chemical precursors. Various preparation techniques produce crystals with varying sizes, but it has been found that nano-sized HAp exhibits a greater number of bioactive properties as compared to micron-sized HAp. Rather than considering conventional methods, this review focuses on alternative approaches such as emulsion, pyrolysis, combustion, and sonochemical methods along with waste bio-sources (biogenic sources) to obtain HAp. We summarize the currently accessible information pertaining to each synthesis process, while also focusing on their benefits and drawbacks.

YD, Anil S, Senthilkumar K, Seong GH, Sargod SS, Bhat SS, Venkatesan J. Remineralizing Potential of Natural Nano-Hydroxyapatite Obtained from Epinephelus chlorostigma in Artificially Induced Early Enamel Lesion: An In Vitro Study

Dental caries is a common problem in adolescents, leading to permanent loss of teeth or cavitation. Caries is a continuous process wherein demineralization and remineralization occur regularly. Hydroxyapatite (HA) is one of the most biocompatible and bioactive materials, as it closely resembles the mineral composition of teeth. The present study deals with isolating hydroxyapatite from fish bone (Epinephelus chlorostigma) by alkaline hydrolysis and thermal calcination. The isolated nano HA was characterized using FT-IR, XRD, TGA, FE-SEM-EDX, and HR-TEM analysis. The nano HA isolated by alkaline hydrolysis is nontoxic, and the cells are viable. The isolated HA enhances the proliferation of L929 cells. The remineralization potential of the extracted nano HA was evaluated in healthy premolars by DIAGNOdent/laser fluorescence quantification, surface microhardness test, and SEM-EDX analysis. Surface morphological observations in SEM and EDX analyses show that thermally calcined HA and alkali-treated HA can induce mineralization and deposit minerals. Therefore, HA obtained from Epinephelus chlorostigma could be a potential biomaterial for treating early caries.

Synthesis of nano hydroxyapatite from Hypopthalmichthys molitrix (silver carp) bone waste by two different methods: a comparative biophysical and in vitro evaluation on osteoblast MG63 cell lines

More than a thousand tonnes of fish bone wastes can be transformed into biomedical products annually. Alkaline hydrolysis and thermal calcification were used to create nanosized hydroxyapatite (HAp) crystals from Silver carp bone wastes. Biophysical tests were used to determine the nano size and chemical composition of synthesised hydroxyapatite. Alkaline hydrolysis hydroxyapatite (AH-HAp) was 58.3 nm, while Thermal calcination hydroxyapatite (TC-HAp) was 64.3 nm in size, confirmed by Atomic Force Microscopy. Energy Dispersive X-ray Analysis studies showed Ca/P (Calcium phosphate) ratio of AH-HAp to be 1.65, whereas TC-HAp as 1.45, confirming AH-HAp to be organically rich along with a similar Ca/P ratio as natural HAp. Fourier Transform Infrared Spectroscopy spectra indicated HAp formation from both procedures, however AH-HAp had superior crystallinity than TC-HAp confirmed from X-Ray Diffraction spectra. MG63 osteoblast cell lines showed 91% cell viability in cytotoxicity studies and 70.1% proliferation efficiency in Alkaline Phosphatase assay, which was higher than TC-HAp. The present study shows that HAp produced via alkaline hydrolysis has better biocompatibility which enhances its applicability as a biomaterial, than HAp synthesized through thermal calcination, which tends to incinerate organic moieties.

Value-added materials recovered from waste bone biomass: technologies and applications

As the world population increases, the generation of waste bones will multiply exponentially, increasing landfill usage and posing health risks. This review aims to shed light on technologies for recovering valuable materials (e.g., alkaline earth material oxide such as CaO, hydroxyapatite, beta tri-calcium phosphate, phosphate and bone char) from waste bones, and discuss their potential applications as an adsorbent, catalyst and catalyst support, hydroxyapatite for tissue engineering, electrodes for energy storage, and phosphate source for soil remediation. Waste bone derived hydroxyapatite and bone char have found applications as a catalyst or catalyst support in organic synthesis, selective oxidation, biodiesel production, hydrocracking of heavy oil, selective hydrogenation and synthesis of bioactive compounds. With the help of this study, researchers can gather comprehensive data on studies regarding the recycling of waste bones, which will help them identify material recovery technologies and their applications in a single document. Furthermore, this work identifies areas for further research and development as well as areas for scaling-up, which will lead to reduced manufacturing costs and environmental impact. The idea behind this is to promote a sustainable environment and a circular economy concept in which waste bones are used as raw materials to produce new materials or for energy recovery.

Synthesis and characterization of a heterogeneous catalyst from a mixture of waste animal teeth and bone for castor seed oil biodiesel production

The present study focused on the synthesis of heterogeneous catalyst from a mixture of waste animal teeth and bone through thermal method. The produced catalyst was used for castor seed oil (CO) biodiesel production. A different mixing ratio of teeth and bone was used with a calcination temperature range from 650 °C to 1250 °C with 100 °C increment for 3h calcination duration. Thermogravimetric analysis (TGA) for animal teeth and bone was performed to identify the common decomposition temperature range. The effect of calcination temperature on basicity of the catalyst and yield of biodiesel was studied for each teeth and bone mixing ratio. Maximum basicity of 6.12mmol HCl/g and biodiesel of 89.5wt% was obtained by mixing ratio of 25wt% teeth and 75wt% bone at calcination temperature of 1150 °C for 3h. The purity of the produced biodiesel in terms of mono fatty acid methyl esters (FAME) formation was found to be 92.6%. X-ray Diffraction (XRD), X-Ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FT-IR) and TGA was used to characterize the raw and produced catalyst. The maximum yield of FAME (89.5wt% with 92.6% purity) was obtained by 5wt% catalyst loading and 9:1 M ratio of methanol to castor seed oil at 60 °C reaction temperature for 3h. Compositional analysis of the produced CO FAME was performed by FT-IR, gas chromatography-mass spectroscopy (GC-MS) and nuclear magnetic resonance (NMR). The performance of the produced catalyst was also checked using its reusability for transesterification CO. Further, the physico-chemical properties including rheological properties of the produced CO FAME were characterized by ASTM methods to check its suitability as a liquid biofuel.

A 3D-Printed Polycaprolactone/Marine Collagen Scaffold Reinforced with Carbonated Hydroxyapatite from Fish Bones for Bone Regeneration

In bone tissue regeneration, extracellular matrix (ECM) and bioceramics are important factors, because of their osteogenic potential and cell–matrix interactions. Surface modifications with hydrophilic material including proteins show significant potential in tissue engineering applications, because scaffolds are generally fabricated using synthetic polymers and bioceramics. In the present study, carbonated hydroxyapatite (CHA) and marine atelocollagen (MC) were extracted from the bones and skins, respectively, of Paralichthys olivaceus. The extracted CHA was characterized using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis, while MC was characterized using FTIR spectroscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The scaffolds consisting of polycaprolactone (PCL), and different compositions of CHA (2.5%, 5%, and 10%) were fabricated using a three-axis plotting system and coated with 2% MC. Then, the MC3T3-E1 cells were seeded on the scaffolds to evaluate the osteogenic differentiation in vitro, and in vivo calvarial implantation of the scaffolds was performed to study bone tissue regeneration. The results of mineralization confirmed that the MC/PCL, 2.5% CHA/MC/PCL, 5% CHA/MC/PCL, and 10% CHA/MC/PCL scaffolds increased osteogenic differentiation by 302%, 858%, 970%, and 1044%, respectively, compared with pure PCL scaffolds. Consequently, these results suggest that CHA and MC obtained from byproducts of P. olivaceus are superior alternatives for land animal-derived substances.

Novel Trends into the Development of Natural Hydroxyapatite-Based Polymeric Composites for Bone Tissue Engineering

In recent years, the number of people needing bone replacements for the treatment of defects caused by chronic diseases or accidents has continuously increased. To solve these problems, tissue engineering has gained significant attention in the biomedical field, by focusing on the development of suitable materials that improve osseointegration and biologic activity. In this direction, the development of an ideal material that provides good osseointegration, increased antimicrobial activity and preserves good mechanical properties has been the main challenge. Currently, bone tissue engineering focuses on the development of materials with tailorable properties, by combining polymers and ceramics to meet the necessary complex requirements. This study presents the main polymers applied in tissue engineering, considering their advantages and drawbacks. Considering the potential disadvantages of polymers, improving the applicability of the material and the combination with a ceramic material is the optimum pathway to increase the mechanical stability and mineralization process. Thus, ceramic materials obtained from natural sources (e.g., hydroxyapatite) are preferred to improve bioactivity, due to their similarity to the native hydroxyapatite found in the composition of human bone.

A Review on Biphasic Calcium Phosphate Materials Derived from Fish Discards

This review summarizes the results reported on the production of biphasic calcium phosphate (BCP) materials derived from fish wastes (i.e., heads, bones, skins, and viscera), known as fish discards, and offers an in-depth discussion on their promising potential for various applications in many fields, especially the biomedical one. Thus, considerable scientific and technological efforts were recently focused on the capability of these sustainable materials to be transformed into economically attractive and highly valuable by-products. As a consequence of using these wastes, plenty of beneficial social effects, with both economic and environmental impact, will arise. In the biomedical field, there is a strong and continuous interest for the development of innovative solutions for healthcare improvement using alternative materials of biogenic origin. Thus, the orthopedic field has witnessed a significant development due to an increased demand for a large variety of implants, grafts, and/or scaffolds. This is mainly due to the increase of life expectancy and higher frequency of bone-associated injuries and diseases. As a consequence, the domain of bone-tissue engineering has expanded to be able to address a plethora of bone-related traumas and to deliver a viable and efficient substitute to allografts or autografts by combining bioactive materials and cells for bone-tissue ingrowth. Among biomaterials, calcium phosphate (CaP)-based bio-ceramics are widely used in medicine, in particular in orthopedics and dentistry, due to their excellent bioactive, osteoconductive, and osteointegrative characteristics. Recently, BCP materials (synthetic or natural), a class of CaP, which consist of a mixture of two phases, hydroxyapatite (HA) and beta tricalcium phosphate (β-TCP), in different concentrations, gained increased attention due to their superior overall performances as compared to single-phase formulations. Moreover, the exploitation of BCP materials from by-products of fish industry was reported to be a safe, cheap, and simple procedure. In the dedicated literature, there are many reviews on synthetic HA, β-TCP, or BCP materials, but to the best of our knowledge, this is the first collection of results on the effects of processing conditions on the morphological, compositional, structural, mechanical, and biological properties of the fish discard-derived BCPs along with the tailoring of their features for various applications.

Synthesis techniques, characterization and mechanical properties of natural derived hydroxyapatite scaffolds for bone implants: a review

Hydroxyapatite (HAp) with good mechanical properties is a promising material meant for a number of useful bids in dentistry and orthopedic for biomedical engineering applications for drug delivery, bone defect fillers, bone cements, etc. In this paper, a comprehensive review has been done, by reviewing different literatures related to synthesis techniques, mechanical properties and property testing, method of calcination and characterization of hydroxyapatite which are product of catfish and bovine bones. The discussion is in relations of the obligatory features vital to attain the best properties for the envisioned bid of bone graft. The process approaches that are capable of fabricating the essential microstructure and the ways to advance the mechanical properties of natural mined HAp are reviewed. The standard values for tensile strength were found to be within the range of 40–300 MPa, compressive strength was 400–900 MPa, while Elastic modulus was 80–120 GPa and fracture toughness was 0.6–1 MPa m1/2 (Ramesh et al. in Ceram Int 44(9):10525–10530, 2018; Landi et al. in J Eur Ceram Soc 20(14–15):2377–2387, 2000; Munar et al. in Dent Mater J 25(1):51–58, 2006). Also, the porosity range was 70–85% (Yang et al. in Am Ceram Soc Bull 89(2):24–32, 2010), density is 3.16 g/cm3 and relative density is 95–99.5% (Ramesh et al. 2018; Landi et al. 2000; Munar et al. 2006). The literature revealed that CaP ratio varies in relation to the source and sintering temperature. For example, for bovine bone, a CaP ratio of 1.7 (Mezahi et al. in J Therm Anal Calorim 95(1):21–29, 2009) and 1.65 (Barakat et al. in J Mater Process Technol 209(7):3408–3415, 2009) was obtained at 1100 °C and 750 °C respectively. Basic understanding on the effect of adding foreign material as a strengthening agent to the mechanical properties of HAp is ground factor for the development of new biomaterial (Natural hydroxyapatite, NHAp). Therefore, it is inferred that upon careful combination of main parameters such as compaction pressures, sintering temperatures, and sintering dwell times for production natural HAp (NHAp), mechanical properties can be enhanced.

Graphic abstract

Synthesis and characterization of nano-hydroxyapatite from Sardinella longiceps fish bone and its effects on human osteoblast bone cells

Organic debris in the form of fish bone wastes account to several thousand tons annually. In recent years, researchers have turned attention towards the bioconversion of organic debris into materials with biomedical applications. Accordingly, the present study synthesized nano-Hydroxyapatite (n-HAP) from bones of discarded Sardinella longiceps by the alkaline hydrolysis method. The synthesized n-HAP was characterized by using the scanning electron microscope (SEM), X-ray diffraction (XRD), atomic force microscope (AFM), and Fourier transform infrared spectroscopy (FTIR). Crushed fish bone demonstrated an agglomerate of fine and rod-like crystals as observed in SEM, whereas n-HAP exhibited a structure of dense thick particles. FTIR spectral data confirmed the functional groups such as alkanes, esters, saturated aliphatic, and aromatic groups. XRD analysis exhibited strong diffraction peaks of HAP confirming its presence in synthesized n-HAP. AFM analysis affirmed that the synthesized particles had an average size of 19.65 nm. Cell viability was tested at different concentrations (10, 50, 100, 250 μg/mL) against human osteoblast bone cells (MG-63).The maximum cell viability (141.3 ± 3.1%) was observed at 100 μg/mL (24 h). Mineralization was evaluated using Alizarin red staining of osteoblast MG-63 cells treated with n-HAP at the concentration of 50 and 100 μg/mL (0.54 ± 0.03 and 0.99 ± 0.05%) which exhibited red color indicating good results. The size, morphology, functional groups, viability and mineralization of the synthesized n-HAP are favorable for its use in bone tissue engineering and other potential osteo and dental applications.

Biogenic Calcium Phosphate from Fish Discards and By-Products

Every year, millions of tons of fish waste are generated from fishing activities, and a similar amount is discarded and returned to the sea as unwanted catches. This material can be used as a biological source for many potential new added-value products, such asobtaining hyaluronic acid from fish eyeballs or extracting collagen from fish skin, but there are not many utilities for fish bones yet. This work tackles the transformation of fish discards into calcium phosphates. Discards from scorpionfish (Scorpaena scrofa) and Atlantic horse mackerel (Trachurus trachurus), as well as by-products generated from aquaculture activities (heads and trimmings frames) of salmon (Salmon salar), were used to obtain calcium phosphate. Biphasic carbonated hydroxyapatite (HA) /beta-tricalcium phosphate (TCP) material was obtained. The biphasic HA-TCP material has a promising range of applications in the biomedical field based on its similarity to calcium phosphates found in human bones in terms of crystallite size and carbonate content. The presence of Na, Mg, Sr, and K ions in the HA-TCP material is very beneficial, since they contribute to bone metabolism and cell adhesion.

Biomaterial for Bone and Dental Implants: Synthesis of B-Type Carbonated Hydroxyapatite from Biogenic Source

There are several sources from which hydroxyapatite (HAp) can be obtained and may be broadly categorized as synthetic or biogenic. Elevated interest in recent times has pushed for the development of several procedures for extracting HAp from biogenic wastes due to their excellent composition and morphology resemblance to the human calcified tissue (B-type carbonated HAp). Notable biogenic sources reported for HAp extraction span bovine bones, fish scales, corals, eggshells, and snails among other calcium-rich sources. However, most of the synthetic methods are laborious and therefore result in high production costs. In this chapter, we discuss the synthesis of B-type carbonate substituted HAp from an untapped biogenic source, Achatina achatina shells, using a simple precipitation method and a controlled heat-treatment method. This unique treatment method affected the substitution resulting in different crystallographic parameters and revealed a novel material for bone implants and enamel applications.

A facile one-step preparation of Ca10(PO4)6(OH)2/Li-BioMOFs resin nanocomposites with Glycyrrhiza glabra (licorice) root juice as green capping agent and mechanical properties study

The Ca₁₀(PO₄)₆(OH)₂/Li-BioMOFs resin nanocomposites were prepared and introduced as a new dental resin nanocomposite. Ca₁₀(PO₄)₆(OH)₂/Li-BioMOFs resin nanocomposites were synthesized with individual mechanical properties in the presence of lecithin as a biostabilizer. The hydrothermal synthesis of hydroxyapatite (HAp) nanostructures occurred in the presence of Glycyrrhiza glabra (liquorice) root juice that acts not only as a green capping agent but also as a reductant compound with a high steric hindrance agent. Results showed that the mechanical properties of nano-Ca₁₀(PO₄)₆(OH)₂ structures with a concentration of 60 ppm Li-BioMOF were increased by ∼132.5 MPa and 11.5 GPa for the flexural and Young's modulus, respectively. Based on the optical absorption ultraviolet-visible spectrum, the HAp nanocrystallites had a direct bandgap energy of 4.2 eV. The structural, morphological, and mechanical properties of the as-prepared nanoparticles were characterized with the FT-IR (Fourier-transform infra-red), UV-Vis (ultraviolet visible) spectrums, X-ray diffraction, SEM (scanning electron microscopy), and TEM (transmission electron microscopy) images, and atomic force microscopy (AFM). It is suggested that HAp structures loaded on the Li-BioMOFs are as a suitable and novel substrate which can be considered as a promising biomaterial in dental resin nanocomposites significantly improved the strength and modulus.

Interfacial bonding between mineral platelets in bone and its effect on mechanical properties of bone

Bone is a composite material consisting principally of apatite mineral, collagen fibrils, non-collagenous proteins, and other organic species. Recent electron microscopy studies have shown that the mineral in bone occurs as stacks of thin polycrystalline sheets ("mineral lamellae," MLs) which surround and lie between the collagen fibrils. We focus on the effect of the interface between these mineral lamellae on the mechanical properties of bone. Previous studies on bone treated with sodium hypochlorite (NaClO) to remove all organic material showed a greatly weakened mineral framework. Here, we treated femoral cortical bone with ethylenediamine (EDA), which only removes collagen, to study the effect of its removal on bone properties. We tested the degree of completion of the treatment by Raman spectroscopy and thermogravimetric analysis. When only collagen is removed, a continuous mineral structure remains and is less weakened than by NaClO treatment. Transmission electron microscopy study of finely ground particles of the EDA treated bone shows that stacks of MLs remain joined, whereas in NaClO treated bone, only isolated crystals are present. Thus, we infer that the MLs in bone are held together in stacks by an organic glue, which is destroyed by NaClO, but which survives the EDA treatment. We show that this glue may contribute to the stiffness, strength, and energy absorption of bone. Further studies are needed to discover the chemical nature of this glue. This study provides a starting point for such investigations.

Fabrication and in-vitro biocompatibility of freeze-dried CTS-nHA and CTS-nBG scaffolds for bone regeneration applications

The thought of biodegradable organic-inorganic composites composed of natural polymer chitosan and ceramic nanoparticles (hydroxyapatite and bioglass) can be considered as a solution for hard tissue engineering. In this paper, we described a comparative assessment of chitosan-nanohydroxyapatite (CTS-nHA) and chitosan-nano-bioglass (CTS-nBG) scaffolds. The dispersion of nanoscaled hydroxyapatite (nHA) and bioglass (nBG) in chitosan remained satisfactory. The freeze-dried composite based CTS-nHA and CTS-nBG scaffolds shown porous structure. The physiochemical and morphological analysis of all samples has been performed through X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The SEM image confirmed the presence of spherically shaped nHA particles of 4.20 μm and irregularly shaped nBG particles of 6.89 μm. The TEM analysis revealed the existence of 165.52 to 255.17 nm sized nHA particles and 167.35 to 334.69 nm sized nBG particles. TEM analysis also showed the interconnected structure of CTS-nHA and CTS-nBG nanocomposites. After seven days' incubation period, the CTS-nHA and CTS-nBG scaffolds shown good mineralization behavior in simulated body fluid (SBF). The CTS-nHA scaffolds exhibited enhanced compressive strength and elastic modulus compared with the CTS-nBG sample. The cell culture experiment revealed that fabricated scaffolds had good compatibility with fibroblast cells (L929, ATCC) and MG-63 which are able to adhere, proliferate, and migrate through the porous structure. All the obtained results clearly recommend that pre-loaded hydroxyapatite and bioglass nanoparticles can enhance the apatite formation. The scaffolds with chitosan, bioglass, and hydroxyapatite have better biomechanical characteristics and allow cell growth. Therefore, these scaffolds can be perfect candidates for various hard tissue engineering applications such as bone regeneration.

Synergistic antioxidant capacity of CsNPs and CurNPs against cytotoxicity, genotoxicity and pro-inflammatory mediators induced by hydroxyapatite nanoparticles in male rats

Due to their dynamic characteristics, hydroxyapatite nanoparticles (HAP-NPs) have been employed numerous times in nanomedicine and in tissue engineering, particularly as diagnostic and therapeutic agents. However, there are outstanding findings from various studies that question whether these NPs are safe when they are used in the human body. Therefore, a more in-depth toxicity assessment should be carried out to give a clear answer regarding the fate of these particles. Here we aim to investigate the possible cytotoxicity, genotoxicity and inflammation induced by HAP-NPs, as well as predict the synergistic antioxidative effect of chitosan nanoparticles (CsNPs) and curcumin nanoparticles (CurNPs) in mitigating this pronounced toxicity. The present study was conducted on eighty Wistar male rats, divided into eight equal groups. The results showed that, at the molecular level, HAP-NPs significantly induced gene expression of tumor suppressor protein p53, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and also Kidney Injury Molecule-1 (KIM-1) and Lipocalin-2 (LCN2). In addition, kidney biochemical parameters (total bilirubin, urea, uric acid and creatinine) increased, but albumin levels decreased in the group treated with HAP-NPs alone. Meanwhile, co-treatment with CsNPs and/or CurNPs with HAP-NPs showed an improvement in the activities of the kidney parameters and reduced inflammation. This study shows that the nephrotoxicity mechanism of HAP-NPs may involve various signaling pathways including alterations in biochemical parameters, gene expression of KIM-1 and LCN2 and disturbing the production of cytokines and p53. Furthermore, these insights showed that the combined effect of both CsNPs and CurNPs was more pronounced than the effect of each one on its own.

Current Status on Pulsed Laser Deposition of Coatings from Animal-Origin Calcium Phosphate Sources

The aim of this paper is to present the current status on animal-origin hydroxyapatite (HA) coatings synthesized by Pulsed Laser Deposition (PLD) technique for medical implant applications. PLD as a thin film synthesis method, although limited in terms of surface covered area, still gathers interest among researchers due to its advantages such as stoichiometric transfer, thickness control, film adherence, and relatively simple experimental set-up. While animal-origin HA synthesized by bacteria or extracted from animal bones, eggshells, and clams was tested in the form of thin films or scaffolds as a bioactive agent before, the reported results on PLD coatings from HA materials extracted from natural sources were not gathered and compared until the present study. Since natural apatite contains trace elements and new functional groups, such as CO32− and HPO42− in its complex molecules, physical-chemical results on the transfer of animal-origin HA by PLD are extremely interesting due to the stoichiometric transfer possibilities of this technique. The points of interest of this paper are the origin of HA from various sustainable resources, the extraction methods employed, the supplemental functional groups, and ions present in animal-origin HA targets and coatings as compared to synthetic HA, the coatings’ morphology function of the type of HA, and the structure and crystalline status after deposition (where properties were superior to synthetic HA), and the influence of various dopants on these properties. The most interesting studies published in the last decade in scientific literature were compared and morphological, elemental, structural, and mechanical data were compiled and interpreted. The biological response of different types of animal-origin apatites on a variety of cell types was qualitatively assessed by comparing MTS assay data of various studies, where the testing conditions were possible. Antibacterial and antifungal activity of some doped animal-origin HA coatings was also discussed.

Syntheses of hydroxyapatite from natural sources

Waste materials from natural sources are important resources for extraction and recovery of valuable compounds. Transformation of these waste materials into valuable materials requires specific techniques and approaches. Hydroxyapatite (HAp) is a biomaterial that can be extracted from natural wastes. HAp has been widely used in biomedical applications owing to its excellent bioactivity, high biocompatibility, and excellent osteoconduction characteristics. Thus, HAp is gaining prominence for applications as orthopaedic implants and dental materials. This review summarizes some of the recent methods for extraction of HAp from natural sources including mammalian, aquatic or marine sources, shell sources, plants and algae, and from mineral sources. The extraction methods used to obtain hydroxyapatite are also described. The effect of extraction process and natural waste source on the critical properties of the HAp such as Ca/P ratio, crystallinity and phase assemblage, particle sizes, and morphology are discussed herein.

Deproteinization of Cortical Bone: Effects of Different Treatments

Bone is a biological composite material having collagen and mineral as its main constituents. In order to better understand the arrangement of the mineral phase in bone, porcine cortical bone was deproteinized using different chemical treatments. This study aims to determine the best method to remove the protein constituent while preserving the mineral component. Chemicals used were H₂O₂, NaOCl, NaOH, and KOH, and the efficacy of deproteinization treatments was determined by thermogravimetric analysis and Raman spectroscopy. The structure of the residual mineral parts was examined using scanning electron microscopy. X-ray diffraction was used to confirm that the mineral component was not altered by the chemical treatments. NaOCl was found to be the most effective method for deproteinization and the mineral phase was self-standing, supporting the hypothesis that bone is an interpenetrating composite. Thermogravimetric analyses and Raman spectroscopy results showed the preservation of mineral crystallinity and presence of residual organic material after all chemical treatments. A defatting step, which has not previously been used in conjunction with deproteinization to isolate the mineral phase, was also used. Finally, Raman spectroscopy demonstrated that the inclusion of a defatting procedure resulted in the removal of some but not all residual protein in the bone.

Natural calcium phosphates from fish bones and their potential biomedical applications

The treatment and recovery of bio-wastes have raised considerable attention both from the environmental and economic point of view. Every year, a remarkable amount of fish processing by-products are generated and dumped as waste from all over the world. Fish bones can serve as a raw material for the production of high value-added compounds that can be used in various sectors including agrochemical, biomedical, food and pharmaceutical industries. The calcination of fish bones results in a single phase (hydroxyapatite) or bi-phasic (hydroxyapatite-tricalcium phosphate) bioceramics depending on the processing conditions as well as the content of the fish bones. This review summarizes the literature on the production of hydroxyapatite from fish bones and discusses their potential applications in biomedical field. The effect of processing conditions on the properties of final products including Ca/P ratio, crystal structure, particle shape, particle size and biological properties are presented in the light of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric-differential thermal analysis, bioactivity and biocompatibility investigations.

Characterization of natural hydroxyapatite originated from fish bone and its biocompatibility with osteoblasts

Hydroxyapatite (HAP) was very attractive for using as bone implant material for a long period due to the close similarity with natural bone in composition and osteoconductive properties. In this study, three kinds of natural HAP (nHAP) derived from rainbow trout (Onchorynchus mkiss), cod (Gadus) and salmon (Oncorhynchus keta) bones were prepared using thermal calcination method for the first time. Resultant nHAPs were characterized by fourier transform infrared spectroscopy (FT-IR), x-ray diffraction analysis (XRD), field-emission scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis. Biocompatibility of calcined nHAP was evaluated through MTT cell viability assay and alkaline phosphatase activity experiment using mouse preosteoblast MC3T3-E1. Results of cell experiment indicated that the nHAP originated from rainbow trout and salmon bones showed better biological compatibility compared with the nHAP originated from cod bone and chemical synthetic HAP (cHAP). This is most likely attributed to the different element composition in nHAP, i.e., the nHAP derived from rainbow trout and salmon bones showed the presence of CO₃^2- and Mg²⁺. Therefore, the nHAP originated from rainbow trout and salmon bones have a great potential for application as implant material substitute in bone tissue engineering and the natural waste fish bone product can be used for hydroxyapatite synthesis as a part of bio-waste management.

Physico-chemical characterization and biocompatibility of hydroxyapatite derived from fish waste

The aim of this study was to synthesize hydroxyapatite (HAP) powder from fish waste. The powder was characterized through X-ray diffraction, Fourier transform infrared spectroscopy, ion exchange chromatography, scanning electron microscopy and plasma emission spectrometry. The cyto- and genotoxicity was carried out to demonstrate biocompatibility in vivo by means of rat subcutaneous tissue test. The results showed that the visible crystalline nature of typical apatite crystal structure when they were calcined at 800 °C. Infrared spectroscopy analysis showed similar composition to HAP standard with the presence of carbonate ion demonstrated by wave number values of 871 cm^-1 and 1420 cm^-1 for calcinations at 800 °C. The scanning electronmicrographies depicted the crystal morphology and porous nature with average pore size of ~10 µm. Plasma emission spectrometry and ion exchange chromatography confirmed the presence of Ca and P in the samples. The mean of calcium content was 36.8; Mg was 0.8, Na was 0.7 and K was 0.5. Rat subcutaneous tissue test revealed that HAP presented biocompatibility. Furthermore, the lack of cyto- and genotoxicity in blood, liver, kidney and lung were noticed after 30 days of HAP implantation. Taken together, our results demonstrated that HAP from fish waste exhibits a great potential for using as biomaterial since is represents a simple, effective, low-cost process and satisfactory degree of biocompatibility.

Isolation and Characterization of Nano-Hydroxyapatite from Salmon Fish Bone

Nano-Hydroxyapatite (nHA) was isolated from salmon bone by alkaline hydrolysis. The resulting nHA was characterized using several analytical tools, including thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), to determine the purity of the nHA sample. The removal of organic matter from the raw fish was confirmed by TGA. FT-IR confirmed the presence of a carbonated group and the similarities to synthetic Sigma HA. XRD revealed that the isolated nHA was amorphous. Microscopy demonstrated that the isolated nHA possessed a nanostructure with a size range of 6–37 nm. The obtained nHA interacted with mesenchymal stem cells (MSCs) and was non-toxic. Increased mineralization was observed for nHA treated MSCs compared to the control group. These results suggest that nHA derived from salmon is a promising biomaterial in the field of bone tissue engineering.

Hydroxyapatite-based materials of marine origin: a bioactivity and sintering study

Single phase hydroxyapatite (HAp) and biphasic material hydroxyapatite/β-tricalcium phosphate (HAp/β-TCP) were obtained from a marine source (Atlantic cod fish bones). Here we report a study on the biological properties of these materials, including cytotoxicity, bioactivity and haemocompatibility. Results showed that the materials are not cytotoxic, neither in their powder nor in pellet form; indeed growth of Saos-2 cells was comparable to that of commercial. The haemolysis rate was lower than 2%; hence the materials can be classified as non-haemolytic. Moreover, when immersed in Simulated Body Fluid (SBF), crystal formation was observed on the surface of both materials. The sintering behaviour of the samples was also studied; both powders showed very high sinterability (density higher than 95% of the theoretical value). Overall, these results confirm the suitability of these materials for biomedical applications.

Hydroxyapatite whisker reinforced 63s glass scaffolds for bone tissue engineering

Bioactive glass (BG) is widely used for bone tissue engineering. However, poor mechanical properties are the major shortcomings. In the study, hydroxyapatite nanowhisker (HANw) was used as a reinforcement to improve the mechanical properties. 63s glass/HANw scaffolds were successfully fabricated by selective laser sintering (SLS). It was found that the optimal compressive strength and fracture toughness were achieved when 10 wt.% HANw was added. This led to 36% increase in compressive strength and 83% increase in fracture toughness, respectively, compared with pure 63s glass scaffolds. Different reinforcement mechanisms were analyzed based on the microstructure investigation. Whisker bridging and whisker pulling-out were efficient in absorbing crack propagating energy, resulting in the improvement of the mechanical properties. Moreover, bioactivity and biocompatibility of the scaffolds were evaluated in vitro. The results showed that composite scaffolds with 10 wt.% HANw exhibited good apatite-forming ability and cellular affinity.

In vivo study of chitosan-natural nano hydroxyapatite scaffolds for bone tissue regeneration

Significant development has been achieved with bioceramics and biopolymer scaffolds in the construction of artificial bone. In the present study, we have developed and compared chitosan-micro hydroxyapatite (chitosan-mHA) and chitosan-nano hydroxyapatite (chitosan-nHA) scaffolds as bone graft substitutes. The biocompatibility and cell proliferation of the prepared scaffolds were checked with preosteoblast (MC3T3-E1) cells. Total Volume (TV), bone volume (BV), bone surface (BS), trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular separation (Tb.Sp) were found to be higher in chitosan-nHA than chitosan-mHA scaffold. Hence, we suggest that chitosan-nHA scaffold could be a promising biomaterial for bone tissue engineering.

Extraction of high added value biological compounds from sardine, sardine-type fish and mackerel canning residues--a review

Different valuable compounds, which can be employed in medicine or in other industries (i.e. food, agrochemical, pharmaceutical) can be recovered from by-products and waste from the fish canning industries. They include lipids, proteins, bio-polymers, minerals, amino acids and enzymes; they can be extracted from wastewaters and/or from solid residues (head, viscera, skin, tails and flesh) generated along the canning process, through the filleting, cooking, salting or smoking stages. In this review, the opportunities for the extraction and the valorisation of bioactive compounds from sardine, sardine-type fish and mackerel canning residues are examined and discussed. These are amongst the most consumed fishes in the Mediterranean area; moreover, canning is one of the most important and common methods of preservation. The large quantities of by-products generated have great potentials for the extraction of biologically desirable high added value compounds.

Nanostructured Hydroxyapatite-Chitosan Composite Biomaterial for Bone Tissue Engineering

In the recent years, significant developments have been achieved with chitosan and hydroxyapatite (HAp) scaffolds for bone tissue engineering. In the present study, chitosan/nanostructured hydroxyapatite (Chitosan/nHAp) has been prepared and subsequently characterized physicochemically for bone graft substitution. The nano sized HAp particles were uniformly distributed in the chitosan matrix which was confirmed by Fourier Transform Infrared Spectroscopy, Thermal Gravimetric Analysis, X-Ray Diffraction and Scanning Electron Microscopy analysis. The pore size of the chitosan/nHAp scaffold was found to be 18-372 µm which is suitable for cell attachment and nutrient supplement. Thus, we are suggesting that Chitosan/nHAp could be promising biomaterials for bone tissue engineering.

Osteoporosis treatment: marine algal compounds

Osteoporosis is one of the most common bone diseases that occur due to imbalance during bone formation and bone resorption. About half of all women over the age of 50 will have a fracture on the hip, wrist, or vertebra. Research and treatment of osteoporosis are challenging for researchers and physicians. There are several types of treatments for osteoporosis including most famous bisphosphonates, estrogen agonists/antagonists, parathyroid hormone, estrogen therapy, hormone therapy, and recently developed RANKL inhibition. In the recent days, much attention has been paid for marine algal extracts and compounds for osteoporosis treatment. In this chapter, we extensively deal with marine algae compounds and their rich mineral constituents for osteoporosis treatment.