Nanocrystalline cellulose is an abundant and inexhaustible organic material on Earth. It can be derived from many lignocellulosic plants and also from agricultural residues. They endowed exceptional physicochemical properties, which have promoted their intensive exploration in biomedical application, especially for tissue engineering scaffolds. Nanocrystalline cellulose has been acknowledged due to its low toxicity and low ecotoxicological risks towards living cells. To explore this field, this review provides an overview of nanocrystalline cellulose in designing materials of bone scaffolds. An introduction to nanocrystalline cellulose and its isolation method of acid hydrolysis are discussed following by the application of nanocrystalline cellulose in bone tissue engineering scaffolds. This review also provides comprehensive knowledge and highlights the contribution of nanocrystalline cellulose in terms of mechanical properties, biocompatibility and biodegradability of bone tissue engineering scaffolds. Lastly, the challenges for future scaffold development using nanocrystalline cellulose are also included.

The design of a scaffold of bone tissue engineering plays an important role in ensuring cell viability and cell growth. Therefore, it is a necessity to produce an ideal scaffold by predicting and simulating the properties of the scaffold. Hence, the computational method should be adopted since it has a huge potential to be used in the implementation of the scaffold of bone tissue engineering. To explore the field of computational method in the area of bone tissue engineering, this paper provides an overview of the usage of a computational method in designing a unit cell of bone tissue engineering scaffold. In order to design a unit cell of the scaffold, we discussed two categories of unit cells that can be used to design a feasible scaffold, which are non-parametric and parametric designs. These designs were later described and being categorised into multiple types according to their characteristics, such as circular structures and Triply Periodic Minimal Surface (TPMS) structures. The advantages and disadvantages of these designs were discussed. Moreover, this paper also represents some software that was used in simulating and designing the bone tissue scaffold. The challenges and future work recommendations had also been included in this paper.

Selective Laser Melting (SLM) has emerged as a transformative technology in bone tissue engineering, particularly for fabricating porous scaffolds from titanium alloys. These scaffolds offer a promising solution for treating critical-sized bone defects, providing mechanical support while promoting bone regeneration. A comprehensive review on recent advancements of SLM is provided by presenting a detailed analysis of cutting-edge research in the application of SLM for titanium alloy scaffold production. Key areas explored include structural designs like Triply Periodic Minimal Surfaces, material and process parameters optimization to enhance scaffold properties such as porosity, mechanical strength, and biocompatibility. Furthermore, the review emphasizes recent innovations in surface modification techniques which improve bioactivity and osseointegration to enable scaffolds to mimic the host tissues. In addition, this review provides essential insights in related to the potential of SLM to be adopted in producing personalized and high-performance medical implants. By synthesizing the latest trends and identifying key areas for future research, this paper aims to serve as a vital resource for the advancement and usage of SLM-fabricated scaffolds in clinical applications. The findings underscore the importance of continued innovation in this field, which has the potential to significantly improve patient outcomes in orthopaedics and beyond.