Page 186 - IJB-10-1

International Journal of Bioprinting Nanoclay biopolymer inks for 3D printing

of material selection and allows the incorporation structure of the obtained composite hydrogels. The
of cells, drugs, and growth factors into the hydrogel crosslinked hydrogels’ swelling capacity, pH sensitivity,
matrix. Extrusion-based printing offers a high and their mechanical stability in wet condition were
printing speed and is compatible with various thoroughly assessed. Moreover, preliminary biological
hydrogel formulations. 48-50 investigations were pursued.
(ii) Stereolithography: Stereolithography utilizes a To the best of our knowledge, this work is the first
liquid resin that solidifies upon exposure to light. methodical research on the assessment of alginate, salecan,
This technique enables high-resolution printing and and natural clay for 3D printing. The present research
precise control over the structure. Stereolithography findings lead us to believe that the disclosed nanocomposite
offers excellent spatial resolution and the ability to materials’ design and the default 3D-printed structures
fabricate complex geometries. However, it is limited will have a significant influence on the creation of unique
by the availability of suitable photopolymerizable advanced materials for specialized regenerative therapies.
hydrogels. 46,47
(iii) Inkjet printing: Inkjet printing deposits tiny droplets 2. Materials and methods
of hydrogel ink onto a substrate in a layer-by-layer 2.1. Materials
manner. It is a versatile technique that allows precise Alginic acid sodium salt and calcium chloride were
control over the droplet size and placement. Inkjet acquired from Sigma-Aldrich, Norway. Salecan (>90%
printing enables the creation of heterogeneous purity), which is an β-1,3 glucan with an average molecular
hydrogel structures and is well-suited for fabricating weight of 2,000,000 g/mol, was purchased from Suzhou
tissue scaffolds. Nevertheless, it often suffers from Health Chemicals Co., Ltd. (Suzhou, China). The nanoclay
low printing speed and limited viscosity and powder (natural montmorillonite, Cloisite Na) from
compatibility of material. 47,51 Southern Clay Products Inc. (Gonzales, TX, USA) was
However, limitations include material availability and used. Sulfuric acid (95%–97% purity) was purchased from
properties, resolution constraints, and post-processing Supelco (Darmstadt, Germany) while phenol (min. 99.5%
requirements. The choice of hydrogel material impacts purity) from Chimreactiv SRL (Bucharest, Romania).
not only mechanical strength but also cell viability if Buffer solutions of pH = 2, 5.5, and 7.4 were prepared in
these are included in the printing ink as in the case of our laboratory using deionized water, 0.1 M hydrochloric
bioprinting. 49,51,52 Achieving high resolution with hydrogels acid (HCl, SC Chimreactiv SRL, Bucharest, Romania), and
is challenging, and additional steps are needed for stability phosphate-buffered saline (PBS; pH = 7.4) tablets (137 mM
and functionality. Despite challenges, 3D printing of sodium chloride, 2.7 mM potassium chloride, and 10 mM
hydrogels holds promise for biomedical devices, tissue phosphate buffer; VWR Chemicals, Ohio, USA).
engineering, and drug delivery. Ongoing research aims
to overcome limitations and expand applications in 2.2. Preparation of the crosslinked polysaccharide
regenerative medicine and personalized healthcare. samples
Considering all these aspects, our present study follows The following steps were taken to obtain the crosslinked
the development of novel 3D-printable nanocomposite polysaccharides samples: Powders of salecan and alginate
formulations using alginate–salecan-based hydrogel ink were measured and thoroughly combined in the solid state.
loaded with nanoclay. By manipulating the alginate– The resulted solid blend was poured over the specified
salecan weight fraction, and also the nanofiller amount, amount of bi-distilled water and was mixed very well with
we could fabricate various nanocomposite inks to render a spatula. The samples were kept at 37°C until the next day
3D structures with high printing fidelity and enhanced and stirred mechanically with a spatula from time to time.
porosity through a simple strategy. Our study carefully The obtained homogenous hydrogels were then used in 3D
examined, in terms of physicochemical parameters, printing process.
how salecan and nanoclay affected the properties of In the case of hydrogel-clay samples, firstly, the required
the printing formulations and the final crosslinked amount of clay was added to the bi-distilled water. Then,
hydrogel nanocomposites. In this regard, hydrogel inks’ the clay aqueous dispersion was magnetically mixed for
rheological characteristics were followed as these are 2 h at 350 rpm and ultrasonically processed for 5 min at
essential in the 3D printing process. Scanning electron 30% amplitude (in an ice bath). The dry solid mixture of
microscopy, thermogravimetric, Fourier transform alginate and salecan was then added. Further, the process
infrared, and X-ray diffraction (XRD) analyses were was carried out in accordance with the steps that had
used to investigate the morphological as well as the already been mentioned.

Volume 10 Issue 1 (2024) 178 https://doi.org/10.36922/ijb.0967