Eggshell Waste: A Gold Mine for Sustainable Bioceramics

Development and characterization of PLA nanocomposites reinforced with bio-ceramic particles for orthognathic implants: Enhanced mechanical and biological properties

The clinical application of osteofixation materials is crucial for maxillofacial reconstruction and orthognathic surgeries. To overcome the limitations of traditional metallic implants, bioabsorbable materials are gaining popularity due to their ability to avoid secondary removal surgeries and reduce stress shielding. This study investigates third-generation biomaterials, focusing on polylactic acid (PLA) for its biocompatibility and biodegradability, and hydroxyapatite (HAP) for its bioactive osteoconductive and bioresorbable properties. Eggshell nanoparticles (ES-NP), HAP, and bioinert alumina particles coated with titanium dioxide (TiO2@Al2O3) were prepared using ball milling, co-precipitation, and sol-gel methods, respectively. PLA-based nanocomposites PLA/ESNP/Al2O3 (PEA), PLA/HAP/Al2O3 (PHA), PLA/ESNP/TiO2@Al2O3 (PEAT), and PLA/HAP/TiO2@Al2O3 (PHAT) were fabricated via solvent casting. Characterization techniques including X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and Field-Emission Scanning Electron Microscopy (FE-SEM) were used to analyze the developed nanoparticles and composites. Results indicated PEAT and PHAT composites exhibited tensile strengths of 33.59 ± 0.38 MPa and 32.46 ± 0.46 MPa, tensile moduli of 1756.17 ± 95.43 MPa and 2367.21 ± 158.84 MPa, and shore d hardness values of 84.10 ± 1.45 SHN and 78.00 ± 2.25 SHN, respectively. Both composites achieved a wettability angle of ~65° and surface roughness below 2.19 μm, enhancing osteoblast adhesion. Additionally, MG63 cell viability was approximately 80 %, and hemolysis rates were below 2.17 %, demonstrating their potential for maxillofacial implant applications.

Nanosystems for targeted drug Delivery: Innovations and challenges in overcoming the Blood-Brain barrier for neurodegenerative disease and cancer therapy

The evolution of sophisticated nanosystems has revolutionized biomedicine, notably in treating neurodegenerative diseases and cancer. These systems show potential in delivering medication precisely to affected tissues, improving treatment effectiveness while minimizing side effects. Nevertheless, a major hurdle in targeted drug delivery is breaching the blood-brain barrier (BBB), a selective shield separating the bloodstream from the brain and spinal cord. The tight junctions between endothelial cells in brain capillaries create a formidable physical barrier, alongside efflux transporters that expel harmful molecules. This presents a notable challenge for brain drug delivery. Nanosystems present distinct advantages in overcoming BBB challenges, offering enhanced drug efficacy, reduced side effects, improved stability, and controlled release. Despite their promise, challenges persist, such as the BBB's regional variability hindering uniform drug distribution. Efflux transporters can also limit therapeutic agent efficacy, while nanosystem toxicity necessitates rigorous safety evaluations. Understanding the long-term impact of nanomaterials on the brain remains crucial. Additionally, addressing nanosystem scalability, cost-effectiveness, and safety profiles is vital for widespread clinical implementation. This review delves into the advancements and obstacles of advanced nanosystems in targeted drug delivery for neurodegenerative diseases and cancer therapy, with a focus on overcoming the BBB.

Sustainable Sources of Raw Materials for Additive Manufacturing of Bone-Substituting Biomaterials

The need for sustainable development has never been more urgent, as the world continues to struggle with environmental challenges, such as climate change, pollution, and dwindling natural resources. The use of renewable and recycled waste materials as a source of raw materials for biomaterials and tissue engineering is a promising avenue for sustainable development. Although tissue engineering has rapidly developed, the challenges associated with fulfilling the increasing demand for bone substitutes and implants remain unresolved, particularly as the global population ages. This review provides an overview of waste materials, such as eggshells, seashells, fish residues, and agricultural biomass, that can be transformed into biomaterials for bone tissue engineering. While the development of recycled metals is in its early stages, the use of probiotics and renewable polymers to improve the biofunctionalities of bone implants is highlighted. Despite the advances of additive manufacturing (AM), studies on AM waste-derived bone-substitutes are limited. It is foreseeable that AM technologies can provide a more sustainable alternative to manufacturing biomaterials and implants. The preliminary results of eggshell and seashell-derived calcium phosphate and rice husk ash-derived silica can likely pave the way for more advanced applications of AM waste-derived biomaterials for sustainably addressing several unmet clinical applications.

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.