3D Printed Composite Scaffolds of GelMA and Hydroxyapatite Nanopowders Doped with Mg/Zn Ions to Evaluate the Expression of Genes and Proteins of Osteogenic Markers

Abstract

As bone diseases and defects are constantly increasing, the improvement of bone regeneration techniques is constantly evolving. The main purpose of this scientific study was to obtain and investigate biomaterials that can be used in tissue engineering. In this respect, nanocomposite inks of GelMA modified with hydroxyapatite (HA) substituted with Mg and Zn were developed. Using a 3D bioprinting technique, scaffolds with varying shapes and dimensions were obtained. The following analyses were used in order to study the nanocomposite materials and scaffolds obtained by the 3D printing technique: Fourier transform infrared spectrometry and X-ray diffraction (XRD), scanning electron microscopy (SEM), and micro-computed tomography (Micro-CT). The swelling and dissolvability of each scaffold were also studied. Biological studies, osteopontin (OPN), and osterix (OSX) gene expression evaluations were confirmed at the protein levels, using immunofluorescence coupled with confocal microscopy. These findings suggest the positive effect of magnesium and zinc on the osteogenic differentiation process. OSX fluorescent staining also confirmed the capacity of GelMA-HM5 and GelMA-HZ5 to support osteogenesis, especially of the magnesium enriched scaffold.

3D Printing Technologies in Personalized Medicine, Nanomedicines, and Biopharmaceuticals

“…In this case, hydrogels are constructed, and hence, there is no need for heating during printing or postprocessing steps as water is the only vehicle. However, the rheological properties of the hydrogel remain a challenge, and hence, the PAM technique is commonly combined with FDM printing to construct scaffolds to provide enough mechanical strength made of biocompatible polymers, such as PLA, PCL, or PLGA [ 111 ]. Peptide hydrogel design focuses on the modulation of the amphiphilic balance of the backbone sequence with an optimal arrangement of hydrophobic–hydrophilic units, allowing for spontaneous physical gelation.…”

Tackling current production of HAp and HAp-driven biomaterials

“…The literature describes two HAp crystal forms: a monoclinic form in the P 2 1 / b space group and a hexagonal form in the P 6 3 / m space group. 4 The hexagonal phase is more common due to the susceptibility of the monoclinic form to destabilization by impurities. The hexagonal structure has two Ca sites: Ca1 (aligned with OH − channels) and Ca2 (arranged in a staggered triangular pattern).…”

“…79 For the bulk material, these differences can be perceived in the macro crystal morphology, mechanical properties and even biological behavior (Table 2). 4…”

“…Zn 2+ is the best example of a multipurpose ion since it is reported as an inducer of matrix mineralization towards new bone formation while presenting antimicrobial and anti-inflammatory properties. 4,91 Zn 2+ presents osteogenic properties associated with its participation in many regulatory pathways, being a co-factor of many enzymes, and inhibiting osteoclastic activity, hence, bone resorption. 91…”

“…3 Bone implants and fillers composed of HAp show proper stabilization and fixation to the adjacent tissues, with the formation of a new, biologically active, carbonate apatite layer. 4…”