3D printing of tough nature inspired hierarchical architecture using chicken bone and eggshell biowaste for biomedical applications

An ample amount of biowaste is getting produced on earth and creating an unhygienic situation due to bacterial and other microbial activities. Proteins diet sourced from different animals, particularly chicken and eggs are being consumed by human beings all around the world on a daily basis producing a huge amount of chicken bone and eggshell residues as biowaste. These biowastes, having similarities with human bone composition, can be utilized to develop orthopedic appliances. The chicken bone extract alone does not have enough mechanical properties and hence needs to be blended with some other calcium-rich ingredients to enhance its properties. The eggshell (round-shaped) biowaste mostly composed of calcium carbonate can be used as a reinforcement in the chicken bone extract(rod-shaped) matrix. The green strength of the chicken bone extract is tuned by mixing it with different weight percentages of eggshell powder. Different intricate structures were printed with these ink mixtures using an extrusion-based 3D printer. Mechanical and biocompatibility (invitro) tests are conducted to study, investigate and understand the effect of eggshell powder on the mechanical and biological properties of the printed structures. The C<inf>50</inf>E<inf>50</inf> with equal weight concentration samples show the optimum results in fracture strain (∼62%), toughness (∼0.52 MJ/m³), and resilience (∼0.01789 MJ/m³). However, C<inf>0</inf>E<inf>100</inf> has the lowest swelling ratio (∼13.5%), C<inf>70</inf>E<inf>30</inf> has the lowest weight loss (∼8.1%) and the cell viability of C<inf>0</inf>E<inf>100</inf> is almost 100%. Hence, a wide range of properties (mechanical and biological) can be obtained by varying and controlling the chicken bone extract and eggshell weight proportions and can be utilized as per the need. This study not only opens up a new direction in utilizing and reducing biowaste but also helps humankind in dealing with public health, particularly in orthopedic and dental applications.