Significant advances have been made in the field of tissue engineering (TE), especially in the synthesis of three-dimensional (3D) scaffolds for replacing damaged tissues and organs in laboratory conditions. However, the gaps in knowledge in exploiting these techniques in preclinical trials and beyond and, in particular, in practical scenarios (e.g., replacing real body organs) have not been discussed well in the existing literature. Furthermore, it is observed in the literature that while new techniques for the synthesis of 3D TE scaffold have been developed, some of the earlier techniques are still being used. This implies that the advantages offered by a more recent and advanced technique as compared to the earlier ones are not obvious, and these should be discussed in detail. For example, one needs to be aware of the reason, if any, behind the superiority of traditional electrospinning technique over recent advances in 3D printing technique for the production of 3D scaffolds given the popularity of the former over the latter, indicated by the number of publications in the respective areas. Keeping these points in mind, this review aims to demonstrate the ongoing trend in TE based on the scaffold fabrication techniques, focusing mostly, on the two most widely used techniques, namely, electrospinning and 3D printing, with a special emphasis on preclinical trials and beyond. In this context, the advantages, disadvantages, flexibilities and limitations of the relevant techniques (electrospinner and 3D printer) are discussed. The paper also critically analyzes the applicability, restrictions, and future demands of these techniques in TE including their applications in generating whole body organs. It is concluded that combining these knowledge gaps with the existing body of knowledge on the preparation of laboratory scale 3D scaffolds, would deliver a much better understanding in the future for scientists who are interested in these techniques.

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Designing of nanomaterials has now become a top-priority research goal with a view to developing specific applications in the biomedical fields. In fact, the recent trends in the literature show that there is a lack of in-depth reviews that specifically highlight the current knowledge based on the design and production of nanomaterials. Considerations of size, shape, surface charge and microstructures are important factors in this regard as they affect the performance of nanoparticles (NPs). These parameters are also found to be dependent on their synthesis methods. The characterisation techniques that have been used for the investigation of these nanomaterials are relatively different in their concepts, sample preparation methods and obtained results. Consequently, this review article aims to carry out an in-depth discussion on the recent trends on nanomaterials for biomedical engineering, with a particular emphasis on the choices of the nanomaterials, preparation methods/instruments and characterisations techniques used for designing of nanomaterials. Key applications of these nanomaterials, such as tissue regeneration, medication delivery and wound healing, are also discussed briefly. Covering this knowledge gap will result in a better understanding of the role of nanomaterial design and subsequent larger-scale applications in terms of both its potential and difficulties.

The present work aims to study the in vitro properties of nano-hydroxyapatite/chitosan–gelatin composite materials. In vitro behavior was performed in simulated body fluid (SBF) to verify the formation of apatite layer onto the composite surfaces. The in vitro data proved the deposition of calcium and phosphorus ions onto hydroxyapatite /polymeric composite surfaces especially those containing high concentrations of polymer content. The degradation of the composites decreased with increase in the polymeric matrix content and highly decreased in the presence of citric acid (CA), especially these composites which contain 30% polymeric content. The water absorption of the composites increased with increase in the polymeric content and highly increased with CA addition. The Fourier transformed infrared reflectance (FT-IR) and scanning electron microscope (SEM) for the composites confirmed the formation of bone-like apatite layer on the composite surfaces, especially those containing high content of polymers (30%) with 0.2 M of CA. These promising composites have suitable properties for bio-applications such as bone grafting and bone tissue engineering applications in the future.