3D Printing of Alginate-Natural Clay Hydrogel-Based Nanocomposites

Abstract

Biocompatibility, biodegradability, shear tinning behavior, quick gelation and an easy crosslinking process makes alginate one of the most studied polysaccharides in the field of regenerative medicine. The main purpose of this study was to obtain tissue-like materials suitable for use in bone regeneration. In this respect, alginate and several types of clay were investigated as components of 3D-printing, nanocomposite inks. Using the extrusion-based nozzle, the nanocomposites inks were printed to obtain 3D multilayered scaffolds. To observe the behavior induced by each type of clay on alginate-based inks, rheology studies were performed on composite inks. The structure of the nanocomposites samples was examined using Fourier Transform Infrared Spectrometry and X-ray Diffraction (XRD), while the morphology of the 3D-printed scaffolds was evaluated using Electron Microscopy (SEM, TEM) and Micro-Computed Tomography (Micro-CT). The swelling and dissolvability of each composite scaffold in phosfate buffer solution were followed as function of time. Biological studies indicated that the cells grew in the presence of the alginate sample containing unmodified clay, and were able to proliferate and generate calcium deposits in MG-63 cells in the absence of specific signaling molecules. This study provides novel information on potential manufacturing methods for obtaining nanocomposite hydrogels suitable for 3D printing processes, as well as valuable information on the clay type selection for enabling accurate 3D-printed constructs. Moreover, this study constitutes the first comprehensive report related to the screening of several natural clays for the additive manufacturing of 3D constructs designed for bone reconstruction therapy.

Development of New Collagen/Clay Composite Biomaterials

“…Thus, Coll sample presented the minimum pore size with Dmed = 132 µm while the samples with mineral clays exhibited slightly higher values starting from Dmed = 147 µm for unmodified clay sample (Coll-ClNa) to Dmed ~160 to 170 µm for organomodified mineral clays containing samples [ 33 ]. These findings are in good agreement with other studies that observed greater pore sizes when clay particles are added to the biopolymer matrix [ 41 , 42 , 43 ].…”

“…Thus, the biological evaluation of the composites was found in good agreement with literature data, which suggested that a good biocompatibility occurs only in composites samples with a specific concentration of clay in the polymeric matrices [ 44 ]. The specific concentration refers to the recipe used in the synthesis and could range from 0.01 to 7% w/v [ 43 ].…”

3D-Printing of Silk Nanofibrils Reinforced Alginate for Soft Tissue Engineering

“…X-ray diffraction (XRD, X’Pert Pro X-ray diffractometer, Phillips, Germany) and Fourier transform infrared spectroscopy (Tensor27, Bruker, Germany), operating in the wavenumber range of 4000 cm −1 –400 cm −1 , were used to characterize alginate, hybrid hydrogels and SNFs. The β-sheet content of degummed SNFs in the nanofibrillar state and after the 3D printing process was estimated using the FTIR spectra and Equation (1) [ 37 ]: where A 1515 and A 1630 represent the areas under the bands at 1515 and 1630 cm −1 , respectively. These bands are related to amide I and amide II in the structure of silk, respectively.…”

Alginate-Based Bio-Composites and Their Potential Applications

“…The properties of the obtained materials confirm their use in tissue engineering. According to the biological analysis, these authors showed that the addition of unmodified clay into the alginate polymer allows for the development of cells [ 125 ].…”