The Influence of Eggshell on Bone Regeneration in Preclinical In Vivo Studies

3D Printed Eggshell Microparticle-Laden Thermoplastic Scaffolds for Bone Tissue Engineering

Three-dimensional (3D) printing, an additive manufacturing technique, is increasingly used in the field of tissue engineering. The ability to create complex structures with high precision makes the 3D printing of this material a preferred method for constructing personalized and functional materials. However, the challenge lies in developing affordable and accessible materials with the desired physiochemical and biological properties. In this study, we used eggshell microparticles (ESPs), an example of bioceramic and unconventional biomaterials, to reinforce thermoplastic poly(ε-caprolactone) (PCL) scaffolds via extrusion-based 3D printing. The goal was to conceive a sustainable, affordable, and unique personalized medicine approach. The scaffolds were fabricated with varying concentrations of eggshells, ranging from 0 to 50% (w/w) in the PCL scaffolds. To assess the physicochemical properties, we employed scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and X-ray diffraction analysis. Mechanical properties were evaluated through compression testing, and degradation kinetics were studied through accelerated degradation with the remaining mass ranging between 89.4 and 28.3%. In vitro, we evaluated the characteristics of the scaffolds using the MC3T3-E1 preosteoblasts over a 14 day period. In vitro characterization involved the use of the Alamar blue assay, confocal imaging, and real-time quantitative polymerase chain reaction. The results of this study demonstrate the potential of 3D printed biocomposite scaffolds, consisting of thermoplastic PCL reinforced with ESPs, as a promising alternative for bone-graft applications.

Comparison of the Eggshell and the Porcine Pericardium Membranes for Guided Tissue Regeneration Applications

Guided bone regeneration is frequently used to reconstruct the alveolar bone to rehabilitate the mastication using dental implants. The purpose of this article is to research the properties of eggshell membrane (ESM) and its potential application in tissue engineering. The study focuses on the structural, mechanical, and histological characteristics of ESM extracted from Gallus domesticus eggs and to compare them to a commercially available porcine pericardium membrane (Jason® membrane, botiss biomaterials GmbH, Zossen, Germany). Thus, histology was performed on the ESM, and a comparison of the microstructure through scanning electron microscopy and atomic force microscopy (AFM) was conducted. Also, mechanical tensile strength was evaluated. Samples of ESM were prepared and treated with alcohol for fixation and disinfection. Histological analysis revealed that the ESM architecture is constituted out of loose collagen fibers. However, due to the random arrangement of collagen fibers within the membrane, it might not be an effective barrier and occlusive barrier. Comparative analyses were performed between the ESM and the AFM examinations and demonstrated differences in the surface topography and mechanical properties between the two membranes. The ESM exhibited rougher surfaces and weaker mechanical cohesion attributed to its glycoprotein content. The study concludes that while the ESM displays favorable biocompatibility and resorb ability, its non-uniform collagen arrangement limits its suitability as a guided bone regeneration membrane in the current non-crosslinked native form. Crosslinking techniques may enhance its properties for such applications. Further research is needed to explore modifications and processing methods that could leverage the ESM's unique properties for tissue engineering purposes.

Osteogenic stimulation of osteoprogenitors by putamen ovi peptides and hyaluronic acid

Eggshell peptides (EP) majorly contribute to rapid bone building in chicks, wherefore this paper investigated their potential for stimulating osteogenesis in vitro. In this study, the effects of EP, also called putamen ovi peptides and a combination of hyaluronic acid with EP in cell culture medium were tested towards proliferation, differentiation, gene expression and mineralization of bovine osteoprogenitors and primary human osteoblasts. The influence of EP at concentrations of 0.005 g/L, 0.5 g/L and 0.5 g/L with 0.25% hyaluronic acid was analyzed using immunocytochemical staining of bone-specific matrix proteins, namely collagen type I, osteonectin, osteopontin and osteocalcin, to prove osteoblastic differentiation. Additionally, Richardson-staining was performed. All tests revealed a superior osteoblastic differentiation with EP at 0.5 g/L after 5 days of cultivation. Hyaluronic acid alone showed controversial results and partially constrained osteoblastic differentiation in combination with EP to a level as low as for pure EP at 0.005 g/L. Of particular interest is the osteoblast-typical mineralization, as an important indicator of bone formation, which was measured indirectly via the calcium concentration after cultivation over 4 weeks. The mineralization showed an increase by a factor of 286 during the cultivation of primary human osteoblasts with hyaluronic acid and EP. Meanwhile, cell cultures treated with EP (0.5 g/L) only showed an 80-fold increase in calcium concentration.The influence of EP (0.5 g/L) on primary human osteoblasts was investigated by gene expression after 2 weeks of cultivation. Microarray and qRT-PCR analysis showed a strongly increased expression of main important genes in bone formation, bone regeneration and the physiological bone remodelling processes. Namely, BMP 2, osteopontin and the matrix metalloproteinases 1 and 9, were present during in vitro osteoprogenitor culture with EP. By explicitly underlining the potential of eggshell peptides for stimulating osteogenesis, as well as emphasizing complex and controversial interaction with hyaluronan, this manuscript is relevant for developing new functionalized biomaterials for bone regeneration.

Evaluation of Struthio camelus eggshell as an in vitro alternative to extracted human teeth in preliminary screening studies on dental erosion

OBJECTIVES

This in vitro work investigates the potential of ostrich eggshell as a substitute for extracted human teeth in preliminary screening studies on dental erosion. Additionally, it aims to demonstrate the potential of ostrich eggshell compared to human enamel in evaluating the efficacy of a preventive agent in protecting against dental erosion, using an artificial mouth model.

METHODS

The experiment utilized 96 erosion testing specimens from each substrate, human enamel, and ostrich eggshell. The specimens were subjected to six different experimental regimens of increasing erosive challenge, simulating the consumption of an acidic drink. The acidic drink was delivered at a consistent volume and duration range. Both artificially stimulated and unstimulated saliva flowed throughout the experimental regimens. Surface hardness was measured using a Through-Indenter Viewing hardness tester with a Vickers diamond, while surface profiling was done using a surface contacting profilometer with a diamond stylus. An automated chemistry analyzer system was used to detect calcium and phosphate ions.

RESULTS

The study found that ostrich eggshell specimens demonstrated predictable surface loss, hardness drop, and ion loss due to the acidic challenge. Meanwhile, enamel appeared to fall short in terms of surface hardness predictability. The transient hardness loss phase, which manifests as an overlooked decrease in surface hardness despite significant ion and structural loss, may explain this phenomenon.

CONCLUSIONS

The experiment showed that assessing surface loss is essential in addition to hardness testing, particularly as certain experimental conditions may produce a false perception of tissue recovery despite the actual surface loss. By analyzing the response of ostrich eggshell specimens to erosive challenges, researchers were able to identify an "overlooked" reduction in hardness in enamel specimens. The differences in the structure, chemical composition, and biological response to erosion in the presence of artificial saliva between enamel and ostrich eggshell could explain their distinct behaviors.

Biocompatibility and histological responses of eggshell membrane for dental implant-guided bone regeneration

Guided bone regeneration (GBR) utilizing eggshell membrane (ESM) as a potential biomaterial for dental implant therapy augmentation was explored in this study. ESM, an environmentally friendly waste product, possesses collagen-rich characteristics. The biocompatibility and histological responses of ESM were investigated in a rat model. Twelve young adult Wistar rats were used in this study. ESM samples were implanted in subcutaneous and intramuscular pockets, and samples were collected at 48 hours, 4 weeks, and 8 weeks post-implantation. Histological analysis revealed the changes in ESM over time. Results showed that ESM maintained its structural integrity, induced a moderate cellular response, and exhibited slow degradation, indicating potential biocompatibility. However, the lack of organized collagen arrangement in ESM led to the formation of irregular and polymorphic spaces, allowing cell migration. Encapsulation of ESM by newly proliferating collagen fibers and multinucleated giant cells was observed at later time points, indicating a foreign body reaction. Crosslinking might improve its performance as a separation membrane, as it has the potential to resist enzymatic degradation and enhance biomechanical properties. In conclusion, ESM demonstrated biocompatibility, slow degradation, and lack of foreign body reaction. While not suitable as a complete separation membrane due to irregular collagen arrangement, further research involving crosslinking could enhance its properties, making it a viable option for guided bone regeneration applications in dental implant therapy. This study highlights the potential of repurposing waste materials for medical purposes and underscores the importance of controlled collagen structure in biomaterial development.

Characterization of eggshell as a bio-regeneration material

Objective

The objective of this study was to identify and summarize the characteristic features of eggshell for regeneration purpose in oral surgery procedures.

Methods

A review of literature was undertaken based on the PubMed database. A search to reveal the current state of knowledge and the current uses of the eggshell as a biomaterial was performed. The characteristics of the materials, the specific use, the procedure and the outcome were extracted from the articles.

Results

The materials have been found to be used in humans, animals, and in vitro studies. There is a wide use regarding oral surgery especially in experimental models. There have also been attempts to enhance certain properties and improve the capabilities of eggshell as a biomaterial. There is yet a commercial product to be developed and approved for human use.

Conclusions

Eggshell can be an important biowaste which can be of use in guided bone regeneration procedures, but it has not yet entered the commercial phase and approval through official regulation channels.

Editorial for the Special Issue on "Multidisciplinary Insights on Bone Healing"

Animal and human bone damage can be considered differently according to a macro- or micro-level analysis [...].

Effect of magnesium oxide nanoparticles, hydroxyapatite and hydrogel on regeneration of transverse fracture of distal radius

Study's purpose of this study is to conduct synthesis and evaluate the effect of hydroxyapatite (HA) with hydrogel locally magnesium oxide nanoparticles (MgONPS) locally or intraperitoneally (IP) on the healing of the distal third radial fracture. Concentrations of MgONPs 200μg/ml, dissolved in 1 cc distilled water and the solution stirred by a stirrer for 10 min. HA 0.5 mg in 1ml hydrogel and the solution stirring at the vortex for 15 min. These materials were evaluated in vitro to ensure their suitability with the tissues. Seventy-five healthy adult male rabbits, aged about 1.5- 2 years old with average weighting  1.7- 2.3 Kg. B.W were used. Rabbits were divided into three groups randomly (n=25), group A (HA mixed hydrogel applied locally), group B (HA mixed with hydrogel and MgONPs applied locally) and group C (HA mixed hydrogel applied locally and MgONPs IP). Animals were anesthetized by i.m 40 mg/ kg B.W ketamine hydrochloride and 5mg/ kg B.W xylazine. A 5cm incision had made cranio-medially in the skin of the forelimb (right forelimb) and exposure radius and ulna. The macroscopic evaluation revealed that all groups at 2nd week showed bone reaction in different degrees.

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.

Efficacy of Pulsed Electromagnetic Fields on Experimental Osteopenia in Rodents: A Systematic Review

Osteoporosis leads to increased bone fragility and risk of fractures. Different strategies have been employed to reduce bone loss, including the use of a pulsed electromagnetic field (PEMF). Although many experimental studies have demonstrated the effect of PEMF on reduction of bone loss, the outcomes studied are varied and insufficient, and the quality of evidence is unknown. Therefore, the aim of this review was to assess the preclinical evidence on the effect of PEMF on bone loss. The existing challenges were also evaluated, and suggestions were provided to strengthen the quality of evidence in future studies. All original articles concerning the effect of PEMF on osteoporosis in animal models were included. Twenty-four studies met the inclusion criteria, 23 of which suggested that PEMF was effective in reducing bone loss, while one study failed to demonstrate any benefit. Risk of bias analysis suggested that information on key measures to reduce bias was frequently not reported. Animal models for osteoporosis, PEMF intervention regimens, outcomes, and specific bone detection sites seemed to influence the efficacy of PEMF in osteoporosis. Our results indicate the potential benefits of PEMF selection in animal models of osteoporosis. However, due to the heterogeneity of the parameters and the quality of the included literature, comprehensive studies using standardized protocols are warranted to confirm the results. © 2021 Bioelectromagnetics Society.

AK, Olaiya NG, Iqbal MO, Jummaat F, A.K. AS, Adnan AS. Insights into the Role of Biopolymer Aerogel Scaffolds in Tissue Engineering and Regenerative Medicine

The global transplantation market size was valued at USD 8.4 billion in 2020 and is expected to grow at a compound annual growth rate of 11.5% over the forecast period. The increasing demand for tissue transplantation has inspired researchers to find alternative approaches for making artificial tissues and organs function. The unique physicochemical and biological properties of biopolymers and the attractive structural characteristics of aerogels such as extremely high porosity, ultra low-density, and high surface area make combining these materials of great interest in tissue scaffolding and regenerative medicine applications. Numerous biopolymer aerogel scaffolds have been used to regenerate skin, cartilage, bone, and even heart valves and blood vessels by growing desired cells together with the growth factor in tissue engineering scaffolds. This review focuses on the principle of tissue engineering and regenerative medicine and the role of biopolymer aerogel scaffolds in this field, going through the properties and the desirable characteristics of biopolymers and biopolymer tissue scaffolds in tissue engineering applications. The recent advances of using biopolymer aerogel scaffolds in the regeneration of skin, cartilage, bone, and heart valves are also discussed in the present review. Finally, we highlight the main challenges of biopolymer-based scaffolds and the prospects of using these materials in regenerative medicine.