Evolution of bioprinting and current applications.

Bioprinting is a very useful tool that has a huge application potential in different fields of science and biotechnology. In medicine, advances in bioprinting are focused on the printing of cells and tissues for skin regeneration and the manufacture of viable human organs, such as hearts, kidneys, and bones. This review provides a chronological overview of some of the most relevant developments of bioprinting technique and its current status. A search was carried out in SCOPUS, Web of Science, and PubMed databases, and a total of 31,603 papers were found, of which 122 were finally chosen for analysis. These articles cover the most important advances in this technique at the medical level, its applications, and current possibilities. Finally, the paper ends with conclusions about the use of bioprinting and our expectations of this technique. This paper presents a review on the tremendous progress of bioprinting from 1998 to the present day, with many promising results indicating that our society is getting closer to achieving the total reconstruction of damaged tissues and organs and thus solving many healthcare-related problems, including the shortage of organ and tissue donors.

Relationship between shear-thinning rheological properties of bioinks and bioprinting parameters.

Three-dimensional bioprinting is a technology in constant development, mainly due to its extraordinary potential to revolutionize regenerative medicine. It allows fabrication through the additive deposition of biochemical products, biological materials, and living cells for the generation of structures in bioengineering. There are various techniques and biomaterials or bioinks that are suitable for bioprinting. Their rheological properties are directly related to the quality of these processes. In this study, alginate-based hydrogels were prepared using CaCl2 as ionic crosslinking agent. Their rheological behavior was studied, and simulations of the bioprinting processes under predetermined conditions were carried out, looking for possible relationships between the rheological parameters and the variables used in the bioprinting processes. A clear linear relationship was found between the extrusion pressure and the flow consistency index rheological parameter, k, and between the extrusion time and the flow behavior index rheological parameter, n. This would allow simplification of the repetitive processes currently applied to optimize the extrusion pressure and dispensing head displacement speed, thereby helping to reduce the time and material used as well as to optimize the required bioprinting results.