Читать книгу 3D Printing of Foods - C. Anandharamakrishnan - Страница 57

3D bioprinting is an AM process that involves the fabrication of cells and biomaterials using a digital file to print organ‐like structures in a layer‐by‐layer manner. The process of 3D bioprinting involves a sequence of steps: data acquisition, material selection, bioprinting, and functionalization (Gu et al. 2019). In data acquisition, the information about the 3D models can be obtained using the scanning techniques such as computed tomography (CT), X‐ray imaging, and magnetic resonance imaging (MRI) (Ozbolat and Gudapati 2016). Then the scanned image can be reconstructed to extract the information, or the design can be modelled directly using CAD software. Thereafter the model is sliced into 2D cross‐sections using appropriate slicing software (Figure 2.13). The materials for bioprinting can be selected based on the requirements of printed structures and printing approaches used. The cell cultures, hydrogels, and growth factors are the common base materials used in the bioprinting process. Based on the printing approach used, the system components of the bioprinter would vary. The printed cells are then dispersed in solutions for maturation (Koch et al. 2013). Later the cultured organ is subjected to physical and chemical simulations to determine its targeted function. A similar approach is utilized for the culturing of artificial meat.

The mixture of cell‐matrix and nutrient mixture is supplied and printed from the printer cartridge in the form of layers. The selection of bio‐ink is crucial for successful printing in terms of biocompatibility, printability, and mechanical integrity (Gao et al. 2019). The characteristic feature of bioprinter is the controlled and precise deposition of the biomaterials. The major advantage of bioprinting is the ability to fabricate porous structures in the desired shape with specific functionalities (Ying et al. 2018). 3D bioprinting offers rapid and customized fabrication of scaffolds with higher precision. With recent advancements in technology, the system components of the bioprinter allow for accurate control over the distribution of pore size, pore volume, and interconnectivity of the pores with network formation. Researchers of the University of Missouri used this approach for the printing of a strip of edible porcine tissue (Nachal et al. 2019). A plant‐based cell‐laden hydrogel was utilized for the production of unique textured food using 3D printing (Park et al. 2020). The callus‐based food ink was prepared by blending callus dispersion with 4% alginate in different ratios of 1 : 2, 1 : 1, and 2 : 1 (w/w). The process involves the curing of the callus samples using Ca²⁺ ions that aids in the formation of rigid gel suitable for 3D printing (Figure 2.14). The samples of 1 : 2 and 1 : 1 ratio showed a proper shape fidelity while the sample with excess cell concentrations i.e., 2 : 1 lowered the printing resolution and resulted in deviation from intended dimensions. Thus, the cells immobilized in hydrogel form a cluster and exhibits texture as that of plant tissues. Hence, the concept of callus‐laden food ink showed a promising result in simulating the plant tissues thereby improving the textural properties of 3D printed foods. As food printing is considered, bioprinting seems to have implications on the ethical, cultural, and societal perspectives associated with animal meat consumption. The common challenges encountered during bioprinting are involved in the selection of biomaterials and the maintenance of a sterile working environment to prevent cross‐contamination. The range of biomaterials available currently is very less that limits bioprinting applications in the food sector. Collagen, gelatin, fibrin, and thermoplastic polymers are a few of biomaterials used for fabrication of tissue scaffolds (Asadi et al. 2020). The above‐mentioned limitations must be addressed in order to explore the research opportunities that exist with bioprinting in food applications.

Figure 2.13 Steps involved in 3D bioprinting process.

Figure 2.14 Schematic representation of integration of 3D printing with plant cell culture technologies.

Source: From Park et al. (2020) / With permission of Elsevier.