Assessment of the biointeractivity of a novel vital pulp therapy agent derived from eggshell biowaste: An in vitro study

This study aimed to assess the calcium (Ca2+) and hydroxyl (OH-) ion-releasing ability, namely the biointeractivity of eggshell-derived hydroxyapatite (ESDHA) in comparison with mineral trioxide aggregate (MTA) and calcium hydroxide (CH). ESDHA, MTA and CH samples (n = 10; 8 × 1.6 mm) were immersed in 10 mL of deionised water (37°C, pH 6.8). Ca2+ and OH- ion releases were detected in 1, 7 and 21 days. Scanning electron microscopy and Fourier transform infrared spectroscopy analyses were also conducted. IBM SPSS 20.0 was used for statistical analyses. The cumulative Ca2+ ions (56.22 ± 11.28 ppm) were detected as most significant in ESDHA (day 21; p < 0.05). The OH- ion values of the ESDHA group were statistically higher than MTA and CH (days 1 and 7; p < 0.05). ESDHA and CH showed a similar pattern with sharp peaks in Ca2+, oxygen and carbon elements. ESDHA being a sustainable material with a high ion-releasing ability may be a preferable alternative to the commercial vital pulp therapy agents.

Nano eggshell-based slurry as a direct pulp-capping material: In vitro characterization and histopathological assessment in an experimental animal model

AIM

Pulp vitality is essential for tooth integrity. Following pulp exposure, choosing a suitable pulp-capping material is crucial to maintain pulp vitality. However, the reparative dentine bridge created by calcium hydroxide (Ca(OH)2 ) is generally porous and incomplete. The aim of the current study is to assess the in vitro and in vivo bioactivities of nano eggshell-based slurry (NES), using NES as a direct pulp-capping material, compared with Ca(OH)2 in rabbit animal model.

METHODOLOGY

Nano eggshell powder (NE) was characterized for particle morphology, chemical composition and ion release. In vitro bioactivity was tested by immersion in simulated body fluid (SBF) for 7 days. For histopathological evaluation, 36 adult New Zealand rabbits (72 pulp exposures) were divided into nine groups (n = 8) according to the pulp-capping material (NES, Ca(OH)2 and no capping as negative control group) and the animals were sacrificed after 7, 14 or 28 days. The pulps of the two lower central incisors were exposed and then directly capped by Ca(OH)2 or NES or left untreated. The cavities were then sealed with glass ionomer cement. Teeth were collected for histopathological evaluation using an optical microscope. Pulp haemorrhage, inflammation, fibrosis and calcific bridge formation were assessed. Results were statistically analysed using anova and Tukey's tests.

RESULTS

Nano eggshell particles were spherical with a 20 nm diameter and were composed mainly of calcite. Statistical analysis showed that there was a significant increase in the release of all investigated ions between days 1 and 28, except for copper. NES group showed a significantly higher release of all elements as compared to Ca(OH)2 . Environmental scanning electron microscope micrographs of NES incubated for 7 days in SBF showed the formation of HAp with a Ca/P ratio (1.686). For histopathological evaluation, the difference between groups was statistically significant. At day 28, 75% of the pulps of the Ca(OH)2 group showed mild calcific bridge in comparison with 100% moderate calcific bridge in the NES group. The NES group showed significantly less inflammation at days 7 and 28, and higher fibrosis at day 7 compared with Ca(OH)2 .

CONCLUSIONS

Nano eggshell-based slurry represents a promising novel direct pulp-capping material with favourable pulp tissue response.

Production of Nano Hydroxyapatite and Mg-Whitlockite from Biowaste-Derived products via Continuous Flow Hydrothermal Synthesis: A Step towards Circular Economy

Biowastes from agriculture, sewage, household wastes, and industries comprise promising resources to produce biomaterials while reducing adverse environmental effects. This study focused on utilising waste-derived materials (i.e., eggshells as a calcium source, struvite as a phosphate source, and CH₃COOH as dissolution media) to produce value-added products (i.e., calcium phosphates (CaPs) derived from biomaterials) using a continuous flow hydrothermal synthesis route. The prepared materials were characterised via XRD, FEG-SEM, EDX, FTIR, and TEM analysis. Magnesium whitlockite (Mg-WH) and hydroxyapatite (HA) were produced by single-phase or biphasic CaPs by reacting struvite with either calcium nitrate tetrahydrate or an eggshell solution at 200 °C and 350 °C. Rhombohedral-shaped Mg-WH (23-720 nm) along with tube (50-290 nm diameter, 20-71 nm thickness) and/or ellipsoidal morphologies of HA (273-522 nm width) were observed at 350 °C using HNO₃ or CH₃COOH to prepare the eggshell and struvite solutions, and NH₄OH was used as the pH buffer. The Ca/P (atomic%) ratios obtained ranged between 1.3 and 1.7, indicating the formation of Mg-WH and HA. This study showed that eggshells and struvite usage, along with CH₃COOH, are promising resources as potential sustainable precursors and dissolution media, respectively, to produce CaPs with varying morphologies.

The Effect of Eggshell and Seashell Nanoparticles Alone and Combined With Nd: YAG Laser on Occlusion and Remineralization Potential of Patent Dentinal Tubules: An In Vitro Study

Introduction: There is an interest in developing materials with bioactive potential that could block exposed dentinal tubules. This study compared the effects of eggshell and seashell nanoparticles individually or combined with ND:YAG laser on dentinal tubules occlusion and remineralization. Methods: Fifty radicular dentin discs were prepared from freshly extracted human premolars. The smear layer created by cutting was removed using 37% phosphoric acid gel for 15 sec. The discs were divided into five groups according to the applied treatment(A) (n = 10 each): (A1) control, (A2); Nano eggshells, (A3); Nano seashells, (A4); Nano eggshells + Nd: YAG Laser, and (A5); Nano sea shell + Nd: YAG Laser. Each specimen was evaluated for tubular patency and mineral contents before and after each therapy using ESEM-EDXA energy dispersive spectroscopy for the assessment of tubule occlusion and remineralization. Results: ESEM results revealed a statistically significant decrease in the mean percent changes of the dentinal tubules number after the treatment of the experimental groups compared to the control. The greatest percent decrease was recorded in the seashell NPs + Nd: YAG laser, followed by the eggshell NPs + Nd: YAG laser, then Eggshell NPs only and then Seashell NPs only, while the lowest percentage decrease was recorded in the control group. EDXA revealed that the greatest percentage increase in Ca wt% was recorded in the Eggshell + Nd:YAG laser group, followed by Eggshell only, then Seashell only and then Seashell NPs + Nd: YAG laser, while the lowest percent increase was recorded in the control group. The post hoc test revealed no significant difference between the experimental groups. Conclusions: Both eggshell and seashell nanoparticles are effective in the occlusion and remineralization of dentinal tubules. The combined treatments with Nd: YAG laser had no benefits when compared to the effect of treatments alone.

Effectiveness of Combination of Chitosan Gel and Hydroxyapatite from Crabs Shells (Portunus pelagicus) Waste as Bonegraft on Periodontal Network Regeneration through IL-1 and BMP-2 Analysis

Background. Periodontitis can be treated by regenerating periodontal tissue using a bone graft. Several natural materials such as chitosan and minerals such as hydroxyapatite can be developed to increase periodontal tissue regeneration. Chitosan has a high potential in healing wounds. Hydroxyapatite has excellent properties such as biocompatibility, osteoconductive, osteoinductive, and osteogenesis, making it an ideal material for soft and hard tissue regeneration. Chitosan and hydroxyapatite can be obtained from the shells of crustaceans, such as crabs shells (Portunus pelagicus). Objective. To assess the effectiveness of the combination of chitosan gel and hydroxyapatite powder as a bone graft on periodontal tissue regeneration in experimental animals. Periodontal tissue regeneration was assessed by expressing inflammatory cytokine gene indicators IL-1 and BMP-2. Methods. Experimental laboratory research and clinical trials with posttest only control group design. Twenty-seven Wistar rats were divided into three groups. Then the femoral bone defect was made, the positive control group was given placebo gel, the positive control group was given BATAN hydroxyapatite, and the test group was given a combination of chitosan gel and hydroxyapatite crab shells. Wistar rats were sacrificed on days 7, 14, and 21, and the femur bone was then taken for immunohistochemical analysis to determine the levels of IL-1 and BMP-2. The Kolmogorov–Smirnov test, Levene test, and one-way ANOVA analyzed the data. Results. On days 7, 14, and 21, the expression levels of IL-1 and BMP2 were significantly different between the three groups. The group added with chitosan gel and crab shell HA showed a faster decrease in IL-1 expression than the control group. BMP-2 expression increased in the test group compared to the control group. Conclusion. The combination of chitosan gel and hydroxyapatite inhibited the production of proinflammatory cytokines and increased the production of BMP-2.

G, Adhikari R. Isolation of Antibacterial Nano-Hydroxyapatite Biomaterial from Waste Buffalo Bone and Its Characterization

Hydroxyapatite nanoparticles were isolated from a biowaste, buffalo bone, via the thermal decomposition method. The resulting white powdered material was characterized by Fourier Transformed Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) analysis. The FTIR spectra confirmed that a heat treatment of the bone powder at the temperature at or above 1223 K removed the organic moieties leading to the formation of a pure inorganic biomineral. The XRD analyses showed that the obtained material was nanocrystalline HAp (nano-HAp) with an average grain diameter of 25 nm, while their rod-shaped particles with their tightly agglomerated morphology were confirmed by the SEM analysis. Besides Calcium (Ca), Phosphorous (P), and Oxygen (O), trace amounts of Aluminum (Al), Magnesium (Mg), Copper (Cu), Zirconium (Zr) and Carbon (C) were also found by EDX analysis. Antibacterial activity of nano-HAp against six standard isolates was investigated by the agar well diffusion method and found to be more susceptible to Acinetobacter baumannii while other standard strains such as Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus showed lesser susceptibility and no antibacterial activity was noticed against Salmonella typhi and Methicillin resistant Staphylococcus aureus (MRSA) with the analysed concentration of nano-HAp suggesting its potential application in biomedical fields.

Synthesis of Spinel-Hydroxyapatite Composite Utilizing Bovine Bone and Beverage Can

Spinel-based hydroxyapatite composite (SHC) has been synthesized utilizing bovine bones as the source of the hydroxyapatite (HAp) and beverage cans as the aluminum (Al) source. The bovine bones were defatted and calcined in the air atmosphere to transform them into hydroxyapatite. The beverage cans were cut and milled to obtain fine Al powder and then sieved to obtain three different particle mesh size fractions: +100#, −140# + 170#, and −170#, or Al particle size of >150, 90–150, and <90 µm, respectively. The SHC was synthesized using the self-propagating intermediate-temperature synthesis (SIS) method at 900 °C for 2 h with (HAp:Al:Mg) ratio of (87:10:3 wt.%) and various compaction pressure of 100, 171, and 200 MPa. It was found that the mechanical properties of the SHC are influenced by the Al particle size and the compaction pressure. Smaller particle size produces the tendency of increasing the hardness and reducing the porosity of the composite. Meanwhile, increasing compaction pressure produces a reduction of the SHC porosity. The increase in the hardness is also observed by increasing the compaction pressure except for the smallest Al particle size (<90 µm), where the hardness instead becomes smaller.

Physical and Mechanical Properties of Tilapia Scale Hydroxyapatite-Filled High-Density Polyethylene Composites

The effects of filler loading and silane coupling agent on the properties of hydroxyapatite (HAp)-filled high density polyethylene (HDPE) composites have been studied. The (HAp) powder was successfully produced from tilapia scales using the spray drying process utilized to prepare the HDPE/HAp composites. The FTIR peaks for the untreated HDPE/30HAp composite corresponded to the functional groups of HDPE (C-CH₃) and –CH₂ and HAp (PO₄⁻³ and O-H). The FTIR spectrum for the silane-treated composite showed that the C=O and silanol groups were eliminated, which strongly confirms the chemical interaction between the HAp fillers and the HDPE matrix. The developed composites demonstrated enhanced mechanical performance, and in particular the treated HDPE/30HAp-S composite exhibited superior tensile strength, Young’s modulus and flexural modulus of 28.26 MPa, 1272 MPa and 796 MPa, respectively. In vitro cytotoxicity analysis showed that the developed composites were non-toxic and have great potential to be used for biomedical application.

Eggshell Microparticle Reinforced Scaffolds for Regeneration of Critical Sized Cranial Defects

Scaffold-based approaches for bone regeneration have been studied using a wide range of biomaterials as reinforcing agents to improve the mechanical strength and bioactivity of the 3D constructs. Eggshells are sustainable and inexpensive materials with unique biological and chemical properties to support bone differentiation. The incorporation of eggshell particles within hydrogels yields highly osteoinductive and osteoconductive scaffolds. This study reveals the effects of microparticles of whole eggshells, eggshells without a membrane, and a pristine eggshell membrane on osteogenic differentiation in protein-derived hydrogels. The in vitro studies showed that gels reinforced with eggshells with and without a membrane demonstrated comparable cellular proliferation, osteogenic gene expression, and osteogenic differentiation. Subsequently, in vivo studies were performed to implant eggshell microparticle-reinforced composite hydrogel scaffolds into critical-sized cranial defects in Sprague Dawley (SD) rats for up to 12 weeks to study bone regeneration. The in vivo results showed that the eggshell microparticle-based scaffolds supported an average bone volume of 60 mm³ and a bone density of 2000 HU 12 weeks post implantation. Furthermore, histological analyses of the explanted scaffolds showed that the eggshell microparticle-reinforced scaffolds permitted tissue infiltration and induced bone tissue formation over 12 weeks. The histology staining also indicated that these scaffolds induced significantly higher bone regeneration at 6 and 12 weeks as compared to the blank (no scaffold) and pristine gel scaffolds. The eggshell microparticle-reinforced scaffolds also supported significantly higher bone formation, remodeling, and vascularization over 6 and 12 weeks as confirmed by immunohistochemistry analysis. Collectively, our results indicated that eggshell microparticle-reinforced scaffolds facilitated significant bone regeneration in critical-sized cranial defects.

Avian Egg: A Multifaceted Biomaterial for Tissue Engineering

Most components in avian eggs, offering a natural and environmentally friendly source of raw materials, hold great potential in tissue engineering. An avian egg consists of several beneficial elements: the protective eggshell, the eggshell membrane, the egg white (albumen), and the egg yolk (vitellus). The eggshell is mostly composed of calcium carbonate and has intrinsic biological properties that stimulate bone repair. It is a suitable precursor for the synthesis of hydroxyapatite and calcium phosphate, which are particularly relevant for bone tissue engineering. The eggshell membrane is a thin protein-based layer with a fibrous structure and is constituted of several valuable biopolymers, such as collagen and hyaluronic acid, that are also found in the human extracellular matrix. As a result, the eggshell membrane has found several applications in skin tissue repair and regeneration. The egg white is a protein-rich material that is under investigation for the design of functional protein-based hydrogel scaffolds. The egg yolk, mostly composed of lipids but also diverse essential nutrients (e.g., proteins, minerals, vitamins), has potential applications in wound healing and bone tissue engineering. This review summarizes the advantages and status of each egg component in tissue engineering and regenerative medicine, but also covers their current limitations and future perspectives.

Fabrication of carbon and silver nanomaterials incorporated hydroxyapatite nanocomposites: Enhanced biological and mechanical performances for biomedical applications

Hydroxyapatite is widely utilized for different biomedical applications because of its outstanding biocompatibility and bioactivity. Cuttlefish bones, which are available aplenty, are both inexpensive and eco-friendly sources for calcium carbonate. In the present study, cuttlefish bones-derived HAp nanorods have been utilized to fabricate HAp nanocomposites incorporating 1, 3 and 5 wt% each of GO, MWCNTs, GONRs and Ag NPs. Characterization using such techniques as XRD, FTIR, HRSEM and EDS was performed to analyze the physicochemical properties of nanocomposites, and MTT assay, hemolysis, bioactivity and drug release to evaluate the biological properties. The XRD and HRSEM results reveal that crystallite and particle size increase with increasing wt% of carbon nanomaterials and Ag NPs. However, the addition of nanomaterials did not modify the shape of HAp. The MTT assay and hemolysis results suggest GONRs possess better biocompatibility than GO and CNTs due to their smooth edge structure. While adding carbon materials up to 3 wt% caused an increase in the hardness, adding up to 5 wt% of them caused a decrease in the hardness due to the agglomeration of the particles. Biocompatibility and Vicker's hardness studies show that adding carbon nanomaterials up to 3 wt% caused significant improvement in biocompatibility and mechanical properties. Antibacterial activity test was performed to analyze the ability to preclude the formation of biofilms. The results showed better activity for silver-incorporated nanocomposites in the presence of E. coli and S. aureus bacteria. Drug release studies were performed using lidocaine drug and the results showed nearly similar drug release profile for all the samples except HAg3. Finally, nanocomposite HRA3 could be a suitable candidate for biomedical applications since it shows better biological and mechanical properties than GO and MWCNTs nanocomposites.

Transfer of enrofloxacin, ciprofloxacin, and lincomycin into eggshells and residue depletion in egg components after multiple oral administration to laying hens

Regardless of whether antimicrobial drugs are administered to laying hens legally or illegally, residues of these drugs may be present in the eggs. Even if the eggs are not intended for human consumption, byproducts/biowaste, such as eggshells, may contain residues of the drugs used, which may pose a risk to human health and the environment. In the presented research, 2 different groups of laying hens received enrofloxacin (10 mg/kg body weight) and lincomycin (20 mg/kg body weight) once daily for 5 d. Eggs were collected daily and the concentration of enrofloxacin, its metabolite ciprofloxacin, and lincomycin residue in the eggshells, whole eggs, egg yolks, and egg whites were determined by ultra-high-performance liquid chromatography-tandem mass spectrometry. This study demonstrates the transfer of enrofloxacin, ciprofloxacin, and lincomycin into the eggshells and provides evidence for the distribution into the eggshells after administration of these drugs to laying hens. The enrofloxacin residues were detected in the eggshell for 10 d after cessation of treatment, ciprofloxacin and lincomycin were rapidly eliminated and 2 d after finish drugs administration they were no longer detected in the eggshell.

Subcritical Water Extraction and Hydrolysis of Cod (Gadus morhua) Frames to Produce Bioactive Protein Extracts

The valorization of Atlantic cod (Gadus morhua) frames from a filleting industry was investigated using subcritical water extraction and hydrolysis (SBW) at different temperatures (90, 140, 190 and 250 °C) and 100 bar to obtain extracts rich in proteins, peptides and amino acids. Up to 57.7 g of extract per 100 g of codfish frames were obtained, with nearly total recovery of the protein fraction. At each temperature, protein extracts of decreasing molecular weight were obtained, according to SEC-GPC results. Most of the protein present in the raw material and extracts was collagen and collagen fragments, as suggested by the amino acid profile. Codfish SBW extracts did not show cytotoxicity in the range of concentrations tested and the protein extract obtained at the lowest temperature (90 °C) showed the highest anti-inflammatory potential in human intestinal epithelium cell model. The mineralized residue left after SBW treatment of cod frames was identified as practically pure, crystalline, hydroxyapatite, that may find applications in biomedical field and hard-tissue engineering. This study shows the possible valorization of cod frames using green extraction methods such as SBW process to obtain protein extracts for food and nutraceutical applications.

Emerging marine derived nanohydroxyapatite and their composites for implant and biomedical applications

Implant materials must mimic natural human bones with biocompatibility, osteoconductivity and mechanical stability to successfully replace damaged or disease-affected bones. Synthetic hydroxyapatite was incorporated with bioglass to mimic natural bones for replacing conventional implant materials which has led to certain toxicity issues. Hence, hydroxyapatite (HAp) are recently gaining applicational importance as they are resembling the structure and function of natural bones. Further, nanosized HAp is under extensive research to utilize them as a potential replacement for traditional implants with several exclusive properties. However, chemical synthesis of nano-HAp exhibited toxicity towards normal and healthy cells. Recently, biogenic Hap synthesis from marine and animal sources are introduced as a next generation implant materials, due to their mineral ion and significant porous architecture mediated biocompatibility and bone bonding ability, compared to synthetic HAp. Thus, the purpose of the paper is to give a bird's eye view into the conventional approaches for fabricating nano-HAp, its limitations and the significance of using marine organisms and marine food wastes as a precursor for biogenic nano-Hap production. Moreover, in vivo and in vitro analyses of marine source derived nano-HAp and their potential biomedical applications were also discussed.

Utilization of Eggshell Membrane and Olive Leaf Extract for the Preparation of Functional Materials

Eggshell membrane (ESM) is a natural proteinaceous by-product of the food industry, especially in the pasteurized egg industry, resulting in the availability of much discarded egg waste. In the literature, eggshell (ES) and ESM usage for their adsorbent properties to remove various organic and inorganic hazardous chemicals, especially from wastewater, has gained interest. In addition, agricultural (olive leaf) and food industry (eggshell and eggshell membrane) waste can together be valorized to produce value-added functional products. This study’s objective was to evaluate the eggshell membrane’s loading capacity for bioactive compounds obtained from olive leaf extract (OLE) in order to prepare functional biomaterial. In this study, waste eggshell membranes were used to adsorb the phenolic compounds from olive leaf extract to design functional biomaterials. Using the foam separation method, both separation of the eggshell membrane and adsorption of bioactive compounds to the eggshell membrane were achieved simultaneously. The characterization studies showed that OLE was successfully adsorbed to the eggshell membrane. Cytotoxicity and antimicrobial studies showed that prepared OLE-loaded membranes were functional materials with bioactive properties. In conclusion, ESM was determined as a promising protein in the production of functional antioxidative and antimicrobial food or dietary supplement after the adsorption of bioactive olive leaf polyphenols.

Fabrication and Characterization of Polyvinylpyrrolidone-Eggshell Membrane-Reduced Graphene Oxide Nanofibers for Tissue Engineering Applications

One of the best methods to prevent wound infection and speed up wound healing is wound dressing based on nanofiber-polymer scaffolds, which have acceptable antimicrobial performance and appropriate skin regeneration capabilities. In this paper, the electrospinning method was applied to synthesize the polyvinylpyrrolidone-acrylic acid hydrogel (PVPA)-eggshell membrane (ESM)-reduced graphene oxide (rGO) nanosheets nanocomposite dressings with different reduced graphene oxide contents (0, 0.5, 1, and 2 wt.%). Thus, smooth nanofibers were fabricated, including a high amount of rGO, which reduced the fiber diameter. Based on the results, rGO played an important role in water impermeability. The results showed that by increasing the rGO concentration from 0.5 to 2 wt%, the contact angle value increased persistently. Results showed that compared to PVPA-ESM, the mechanical strength and strain of PVPA-ESM/1 wt% rGO significantly enhanced 28% and 23%, respectively. Incorporation of 1 wt% rGO enhanced swelling ratio from 875% for PVPA-ESM to 1235% after 420 min, while increasing the rGO to 2 wt% increased the degradation rate of the composites. According to the in vitro cell culture studies, PVPA-ESM wound dressings with 0.5-1 wt% rGO content enhanced PC12 cell viability compared to the wound dressings without rGO nanosheets. Generally, rGO-loaded PVPA-ESM nanofiber wound dressing can be considered as a potential candidate to be used in skin regeneration applications.

Multi-Class Procedure for Analysis of 50 Antibacterial Compounds in Eggshells Using Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry

In this work, for the first time, Ultra-High-Performance Liquid Chromatography–Tandem Mass Spectrometry (UHPLC–MS/MS) method was developed for qualitative and quantitative analysis of veterinary antibiotics (cephalosporins, diaminopyrimidines, fluoro(quinolones), lincosamides, macrolides, penicillins, pleuromutilins, sulfonamides, tetracyclines, and sulfones) in hen eggshells. The sample preparation method is based on a liquid–liquid extraction with a mixture of metaphosphoric acid, ascorbic acid, EDTA disodium salt dihydrate, and acetonitrile. The chromatographic separation was performed on Luna^® Omega Polar C18 10 column in gradient elution mode and quantitated in an 8 min run. Validation such as linearity, selectivity, precision, recovery, matrix effect, limit of quantification (LOQ), and limit of detection (LOD) was found to be within the acceptance criteria of the validation guidelines of the Commission Decision 2002/657/EC and EUR 28099 EN. Average recoveries ranged from 81–120%. The calculated LOQ values ranged from 1 to 10 µg/kg, the LOD values ranged from 0.3 to 4.0 µg/kg, depending on analyte. The developed method has been successfully applied to the determination of antibacterial compounds in hen eggshell samples obtained from different sources. The results revealed that enrofloxacin, lincomycin, doxycycline, and oxytetracycline were detected in hen eggshell samples.

Progress on Modified Calcium Oxide Derived Waste-Shell Catalysts for Biodiesel Production

The dwindling of global petroleum deposits and worsening environmental issues have triggered researchers to find an alternative energy such as biodiesel. Biodiesel can be produced via transesterification of vegetable oil or animal fat with alcohol in the presence of a catalyst. A heterogeneous catalyst at an economical price has been studied widely for biodiesel production. It was noted that various types of natural waste shell are a potential calcium resource for generation of bio-based CaO, with comparable chemical characteristics, that greatly enhance the transesterification activity. However, CaO catalyzed transesterification is limited in its stability and studies have shown deterioration of catalytic reactivity when the catalyst is reused for several cycles. For this reason, different approaches are reviewed in the present study, which focuses on modification of waste-shell derived CaO based catalyst with the aim of better transesterification reactivity and high reusability of the catalyst for biodiesel production. The catalyst stability and leaching profile of the modified waste shell derived CaO is discussed. In addition, a critical discussion of the structure, composition of the waste shell, mechanism of CaO catalyzed reaction, recent progress in biodiesel reactor systems and challenges in the industrial sector are also included in this review.

An investigation in the remineralization and acid resistant characteristics of nanohydroxyapatite produced from eggshell waste via mechanochemistry

OBJECTIVES

This study focuses on the properties of nanohydroxyapatite (nHAp) in terms of remineralization and acid resistance. The nHAp were produced from waste eggshells via the mechanochemistry process.

MATERIALS AND METHODS

The characterization was based on Fourier Transform Spectroscopy, X-ray diffraction, Field Scanning Electron Microscope (FESEM), and High-Resolution Electron Microscope to determine the surface morphology of the nHAp. The acid and remineralization properties were evaluated using bovine enamel and dentine models (n = 5) while the buffering properties against acids were studied using a pH meter. The biocompatibility of the produce nHAp was assessed in vitro against NIH 3T3.

RESULTS

The XRD and FTIR results confirm that nHAp were successfully produced from eggshell waste after 5 h of milling. The HRTEM reveals a semi-sphere morphology with an average dimension of 9 to 20 nm. The buffering test suggests that nHAp were highly effective in neutralizing common dietary acids. Also, the nHAp exhibits outstanding remineralization and occluding properties. The cytotoxicity assay suggests that the nHAp had a low toxicity.

CONCLUSION

The study concludes that using eggshell waste to produce nHAp will help in waste management and at the same time, provide valuable biomaterial for the treatment of tooth sensitivity.

Extraction and Characterization of Novel Natural Hydroxyapatite Bioceramic by Thermal Decomposition of Waste Ostrich Bone

A novel natural hydroxyapatite (HAp) bioceramic was extracted from the ostrich cortical bone by the thermal decomposition method. HAp was characterized by different analytical tools such as thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). Removal of organic impurities from the bone powder was confirmed by TGA analysis. FTIR spectra of HAp confirmed the presence of the major functional groups such as phosphate (PO₄³⁻), hydroxyl (OH⁻), and carbonate (CO₃²⁻) in the bioceramic. The XRD data revealed that the HAp was the crystalline phase obtained by calcination of the bone powder at 950°C, and the SEM analyses confirmed the typical plate-like texture of the nanosized HAp crystals.

Naturally Derived a-Tricalcium Phosphate Based Porous Composite Bead Production

In this study, a simple, innovative approach is applied to produce porous a-TCP-CeO2-Al2O3 composite beads via using bovine bone-derived hydroxyapatite, cerium oxide, and alumina ceramics. Bovine-bone derived hydroxyapatite was obtained via calcination of bones at 950°C for 3 hours. Hydroxyapatite is a thermally unstable biomaterial at high temperatures, and depending on its stoichiometry decomposes at 800-1200°C. Sodium alginate was successfully used as an in situ gelling templates for the production of the ceramic beads and starch, an environmentally friendly and economic pore-forming agent, is used to achieve interconnected, highly open porosity containing composite beads. Sintering of the ceramic−starch−alginate green composite beads at 1200°C for 1 hour resulted in the decomposition of the hydroxyapatite phase and formation of a-TCP. XRD analysis revealed that a-TCP-CeO2-Al2O3 composite beads were achieved. XRD analysis confirmed the formation of a-TCP phase in all composite compositions. SEM investigations of the produced composite beads revealed that bimodal pore size distribution, fine and coarse, was achieved.

Synthesis and characterization of hydroxyapatite from bovine bone for production of dental implants

This paper presents a study on the synthesis and characterization of hydroxyapatite that can be used to produce dental implants or serves as a replacement for other body hard tissues. The bioceramic material (hydroxyapatite) was derived from bovine bone samples after they were de-fatted and processed to produce particles measuring less than 250 μm. Processed bone powders were calcinated at 750℃ to obtain calcium phosphate compound (hydroxyapatite). This indicated complete elimination of the organic phase of the bone. The synthesized hydroxyapatite was physico-chemically characterized using Fourier transform infrared spectroscopy (FTIR), an optical microscope and scanning electron microscopy (SEM). Hydroxyapatite powder was sintered into a block and then characterized mechanically by measuring its hardness using a Rockwell hardness testing machine. The hydrophilicity and hydrophobicity of the sintered blocked specimens were studied. The average wettability of the substrate, which was a characteristic of the contact angle, was found to be approximately 31.73 degrees. This contact angle value is a measure of the material hydrophilicity. The biostability/corrosive resistance of the sintered samples was simulated in vitro in phosphate buffered saline solution (pH 7.4) by incubating in an optical incubator shaker (set at 60 revolutions per minute) to mimic physiological conditions. The results showed that hydroxyapatite can be extracted economically from a natural source such as bovine bone and can be employed as a restorative biomaterial for dental implants and hard tissue replacement.

Histomorphometric evaluation of a nano-sized eggshell-containing supplement as a natural alloplast: An animal study

Background

Limitations of autogenous grafts have dictated the need for development of new biomaterials that can serve as allografts. A paradigm shift directed manufacturers to revert to nature in the search for such allografts. This study aimed to evaluate an eggshell-based supplement, Membrell’s® BONEhealth Plus D₃ & K₂, indicated to support bone mineral density, as a natural bone graft material.

Methods

Twelve 5 × 10 × 1 mm full-thickness cranial bone defects were created in six adult male New Zealand rabbits. Six defects were filled with Membrell’s® BONEhealth™ Plus D₃ & K_2, and the others were left empty as control. The animals were sacrificed 14 days postoperatively. The defects were dissected and prepared for histological assessment. Bone formation was compared both qualitatively and quantitatively. The area percent of newly-formed bone was evaluated in five successive regions using image analysis. Statistical analysis was performed using unpaired t-test. Differences between the two groups were considered significant at p ≤ 0.05.

Results

Cranial bone defects filled with the nano-sized eggshell powder “Membrell’s® BONEhealth™ Plus D₃ & K₂” revealed significantly higher levels of osteoid, newly-formed, regularly-arranged bone trabeculae in the center of the defects (47.37% ± 1.12) compared to the control defects (21.6% ± 4.92), which revealed no bone formation. A rapid rate of resorption of the nano-sized eggshell powder and consequently a rapid osteogenic effect was evident.

Conclusions

The eggshell-based graft powder, Membrell’s® BONEhealth™ Plus D₃ & K₂, is a biocompatible material which has the potential to enhance new bone formation.

Cationic Substitutions in Hydroxyapatite: Current Status of the Derived Biofunctional Effects and Their In Vitro Interrogation Methods

High-performance bioceramics are required for preventing failure and prolonging the life-time of bone grafting scaffolds and osseous implants. The proper identification and development of materials with extended functionalities addressing socio-economic needs and health problems constitute important and critical steps at the heart of clinical research. Recent findings in the realm of ion-substituted hydroxyapatite (HA) could pave the road towards significant developments in biomedicine, with an emphasis on a new generation of orthopaedic and dentistry applications, since such bioceramics are able to mimic the structural, compositional and mechanical properties of the bone mineral phase. In fact, the fascinating ability of the HA crystalline lattice to allow for the substitution of calcium ions with a plethora of cationic species has been widely explored in the recent period, with consequent modifications of its physical and chemical features, as well as its functional mechanical and in vitro and in vivo biological performance. A comprehensive inventory of the progresses achieved so far is both opportune and of paramount importance, in order to not only gather and summarize information, but to also allow fellow researchers to compare with ease and filter the best solutions for the cation substitution of HA-based materials and enable the development of multi-functional biomedical designs. The review surveys preparation and synthesis methods, pinpoints all the explored cation dopants, and discloses the full application range of substituted HA. Special attention is dedicated to the antimicrobial efficiency spectrum and cytotoxic trade-off concentration values for various cell lines, highlighting new prophylactic routes for the prevention of implant failure. Importantly, the current in vitro biological tests (widely employed to unveil the biological performance of HA-based materials), and their ability to mimic the in vivo biological interactions, are also critically assessed. Future perspectives are discussed, and a series of recommendations are underlined.

Osteoblast Cell Response to Naturally Derived Calcium Phosphate-Based Materials

The demand of calcium phosphate bioceramics for biomedical applications is constantly increasing. Efficient and cost-effective production can be achieved using naturally derived materials. In this work, calcium phosphate powders, obtained from dolomitic marble and Mytilus galloprovincialis seashells by a previously reported and improved Rathje method were used to fabricate microporous pellets through cold isostatic pressing followed by sintering at 1200 &deg;C. The interaction of the developed materials with MC3T3-E1 pre-osteoblasts was explored in terms of cell adhesion, morphology, viability, proliferation, and differentiation to evaluate their potential for bone regeneration. Results showed appropriate cell adhesion and high viability without distinguishable differences in the morphological features. Likewise, the pre-osteoblast proliferation overtime on both naturally derived calcium phosphate materials showed a statistically significant increase comparable to that of commercial hydroxyapatite, used as reference material. Furthermore, evaluation of the intracellular alkaline phosphatase activity and collagen synthesis and deposition, used as markers of the osteogenic ability of these bioceramics, revealed that all samples promoted pre-osteoblast differentiation. However, a seashell-derived ceramic demonstrated a higher efficacy in inducing cell differentiation, almost equivalent to that of the commercial hydroxyapatite. Therefore, data obtained demonstrate that this naturally sourced calcium-phosphate material holds promise for applications in bone tissue regeneration.

Physicochemical characterization of a dental eggshell powder abrasive material

BACKGROUND

This study aimed to determine the physicochemical characteristics of an eggshell-based dental abrasive material.

METHODS

The eggshell powder abrasive material (EPAM) was synthesized by ball milling eggshell powder and surfactants. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and a laser diffraction particle size analyzer (PSA) were used to characterize EPAM. In addition, the abrasive characteristics of EPAM were evaluated by comparison using poly(methyl methacrylate) (PMMA) resins. Surface roughness (Ra) was measured using a profilometer.

RESULTS

The FTIR spectroscopy and XRD analysis confirmed that the carbonate product was primarily calcite (97.3%) with traces of graphite 2H (1.3%) and thenardite (1.4%). The TEM imagery revealed irregular particles in EPAM. The PSA analysis of the particle size distribution showed EPAM to be a superfine powder (0.3 µm to 50 nm). In addition, the 50-nm EPAM (Ra = 0.04 µm) measured the lowest Ra value when compared with pumice (Ra = 0.08 µm).

CONCLUSIONS

The salient features of this study indicate that EPAM can naturally replace calcite, which is generally mined and used as a dental abrasive material. In addition, and regarding the abrasive characteristics of EPAM in reducing the surface roughness of PMMA resin specimens, this study conclusively showed that EPAM effectively reduces the surface roughness below the threshold limit value of 0.2 µm. Potentially, EPAM could reduce waste disposal problems while enabling an economic benefit from using eggshell waste material.

Separation and preconcentration of riboflavin from human plasma using polythionine coated magnetite/hydroxyapatite nanocomposite prior to analysis by surfactant-enhanced fluorimetry

The exploration of novel adsorption properties of conductive polymers based on hybridization with biocompatible nanomaterials receives an increasing interest. In this regard, hydroxyapatite (HA) bioceramic is of critical importance mainly owing to its facile synthesis, high surface area, economic and low toxicity in biological environments. In this work, we first prepared and characterized a magnetite/hydroxyapatite (Fe₃O₄/HA) nanocomposite using the bio-waste chicken eggshell via an attractive green way that involved low cost and irrespective of toxicity. Then, polythionine as a novel class of conductive polymers was in situ coated on the synthesized magnetic bioceramic for the separation and preconcentration of riboflavin (vitamin B₂) in human plasma before its fluorimetric determination. Considering the putative role of riboflavin in protecting against cancer and cardiovascular diseases, it is essential to evaluate this vitamin in biological fluids. The described method possesses a linear range of 0.75-262.5μgL^-1 (R²=0.9985) and a detection limit of 0.20μgL^-1 (signal-to-noise ratio of 3). The relative standard deviations (RSDs) for single-sorbent repeatability and sorbent-to-sorbent reproducibility were less than 4.0% and 7.6% (n=5), respectively. The respective enrichment factor and extraction recovery of the method found to be 35.7 and 98.4%. The analytical performance of method for riboflavin was characterized by good consistency of the results with those obtained by the enzyme-linked immunosorbent assay (ELISA) conventional method (p-value of <0.05). The optimized protocol intended for control determinations of riboflavin in human subjects and is addressed to clinical laboratories.

Bioactivity and mineralization of natural hydroxyapatite from cuttlefish bone and Bioglass® co-sintered bioceramics

In this study, bioactive hydroxyapatite (HAP)-based bioceramics starting from cuttlefish bone powders have been prepared and characterized. In particular, fragmented cuttlefish bone was co-sintered with 30 wt% of Bioglass^® -45S5 to synthesize HAP-based powders with enhanced mechanical properties and bioactivity. Commercial synthetic HAP was treated following the same procedure and used as a reference. The structure and composition of the bioceramics formulations were characterized using Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. After the thermal treatment of cuttlefish bone powder added with 30 wt% Bioglass, new phases with compositions of sodium calcium phosphate [Na₃ Ca₆ (PO₄ )₅ ], β-tricalcium phosphate [Ca₃ (PO₄ )] and amorphous silica were detected. In vitro cell culture studies were performed by evaluating proliferation, metabolic activity and differentiation of human osteoblast-like cells (MG63). Scaffolds made with cuttlefish bone powder exhibited increased apatite deposition, alkaline phosphatase activity and cell proliferation compared with commercial synthetic HAP. In addition, the ceramic compositions obtained after the combination with Bioglass^® further enhanced the metabolic activity of MG63 cell and promoted the formation of a well-developed apatite layer after 7 days of incubation in Dulbecco's modified Eagle's medium.