No abstract

The classic cell culture involves the use of support in two dimensions, such as a well plate or a Petri dish, that allows the culture of different types of cells. However, this technique does not mimic the natural microenvironment where the cells are exposed to. To solve that, three-dimensional bioprinting techniques were implemented, which involves the use of biopolymers and/or synthetic materials and cells. Because of a lack of information between data sources, the objective of this review paper is, to sum up, all the available information on the topic of bioprinting and to help researchers with the problematics with 3D bioprinters, such as the 3D-Bioplotter™. The 3D-Bioplotter™ has been used in the pre-clinical field since 2000 and could allow the printing of more than one material at the same time, and therefore to increase the complexity of the 3D structure manufactured. It is also very precise with maximum flexibility and a user-friendly and stable software that allows the optimization of the bioprinting process on the technological point of view. Different applications have resulted from the research on this field, mainly focused on regenerative medicine, but the lack of information and/or the possible misunderstandings between papers makes the reproducibility of the tests difficult. Nowadays, the 3D Bioprinting is evolving into another technology called 4D Bioprinting, which promises to be the next step in the bioprinting field and might promote great applications in the future.

Three-dimensional printing technologies allow for the fabrication of complex parts with accurate geometry and less production time. When applied to biomedical applications, two different approaches, known as direct or indirect bioprinting, may be performed. The classical way is to print a support structure, the scaffold, and then culture the cells. Due to the low efficiency of this method, direct bioprinting has been proposed, with or without the use of scaffolds. Scaffolds are the most common technology to culture cells, but bioassembly of cells may be an interesting methodology to mimic the native microenvironment, the extracellular matrix, where the cells interact between themselves. The purpose of this review is to give an updated report about the materials, the bioprinting technologies, and the cells used in cancer research for breast, brain, lung, liver, reproductive, gastric, skin, and bladder associated cancers, to help the development of possible treatments to lower the mortality rates, increasing the effectiveness of guided therapies. This work introduces direct bioprinting to be considered as a key factor above the main tissue engineering technologies.

Powder bed fusion techniques enable the production of customized and complex devices that meet the requirements of the end user and target application. The medical industry relies on these additive manufacturing technologies for the advantages that these methods offer to accurately fit the patients’ needs. Besides the recent improvements, the production process of 3D printed bespoke implants still requires optimization to achieve the optimal properties that can mimic both the chemical and mechanical characteristics of the anatomical region of interest. In particular, the surface properties of an implant device are crucial to obtain a strong interface and connection with the physiological environment. The layer by layer manufacturing processes lead to the production of complex and high-performance substrates but always require surface treatments during post-processing to improve the implant interaction with the natural tissues and promote a shorter assimilation for the fast recovery and wellness of the patient. Although the surface finishing can be tailored to enhance cells adhesion, proliferation and differentiation in contact with a metal implant, the same surface properties can have a different outcome when dealing with bacteria. This work aims to provide a preliminary analysis on how different post-processing techniques have distinct effects on cells and bacteria colonization of 3D printed titanium implants. The goal of the paper is to highlight the importance of the identification of an optimized methodology for the surface treatment of Ti6Al4V samples produced by Selective Laser Melting (SLM) that improves the implant antimicrobial properties and promotes the osseointegration in a long-term period.