3D‐Printed Porous Tantalum Coated with Antitubercular Drugs Achieving Antibacterial Properties and Good Biocompatibility

Abstract

Treatment of bone and joint tuberculosis remains a challenge. The development of tissue‐engineered drug‐loaded biomaterials has increased the therapeutic options. However, for the treatment of osteoarticular tuberculosis with severe local infection risks and high weight‐bearing requirements, it is still necessary to design materials consistent with bone biomechanics, cytocompatibility, and osteogenesis and to provide more effective antimicrobial functions. The antitubercular drugs isoniazid and rifampicin are loaded with gellan gum, and a 3D‐printed porous tantalum surface is treated with polydopamine to increase adhesion. The osteogenic induction and differentiation are tested using alkaline phosphatase, alizarin red staining, sirius red staining, and polymerase chain reaction testing. Bone regeneration in vivo is measured by X‐ray, micro‐computerized tomography, hard tissue sections, and fluorescence staining. The drug is released slowly in vitro and in vivo, increasing the duration of antibacterial action. The composite bio‐scaffolds inhibit Staphylococcus aureus growth, have good biocompatibility, and does not inhibit the induction of osteogenic differentiation of rat bone marrow mesenchymal stem cells. The composite bio‐scaffold can simultaneously achieve localized long‐term controlled drug release and bone regeneration and is a promising route for bone and joint tuberculosis treatment.

Mussel-Inspired Polydopamine-Based Multilayered Coatings for Enhanced Bone Formation

“…The multilayered coating showed outstanding photothermal property and sustained doxorubicin release for tumor inhibition, where the osteogenic activity was also enhanced. Hua et al (Hua et al, 2022) developed a PDA-modified 3D-printed Ta scaffold to load isoniazid and rifampicin for the treatment of osteoarticular tuberculosis, which was demonstrated to achieve long-term drug release and bone regeneration at the same time. The disadvantages of drug-loaded coating mainly lie in the rapid release rate and the risk of drug resistance, which will negatively affect the drug efficiency and inhibit the final bone formation.…”

Translating Material Science into Bone Regenerative Medicine Applications: State-of-The Art Methods and Protocols

“…Cell localization and distribution on the biomaterial can be analyzed by simply labeling the nuclei at different timepoints after cell seeding on the scaffold [ 52 ]. The morphology of the biomaterial-seeded cells can also be examined by scanning electron microscopy (SEM) [ 14 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ], as well as the intracellular structures by transmission electron microscopy (TEM) [ 65 , 68 ]. Cell morphology and distribution can also be assessed using immunofluorescence staining of actin filaments, by means of anti-phalloidin antibodies among others, which allows for the analysis of the cytoskeleton conformation of cell growth in contact with the biomaterials [ 14 , 52 , 54 , 55 , 57 , 60 , 62 , 64 , 65 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ].…”

“…Fluorescent live/dead assays are able to discriminate between live and dead cells by evaluating plasma membrane integrity and the activity of the esterase enzyme, both maintained only in viable cells [ 54 , 55 , 60 , 62 , 70 , 74 , 75 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 ]. Other commercial colorimetric assays for the evaluation of cell viability are available on the market and, among the most widely used are the cell counting kit-8 (CCK-8) assay that allows a sensitive colorimetric measure of viable cells, using a water-soluble tetrazolium salt that produces, in presence of active dehydrogenases in living cells, an orange formazan product, and the amount of formazan produced is directly proportional to the number of viable cells [ 55 , 57 , 58 , 62 , 73 , 76 , 80 , 81 , 85 , 86 , 87 , 88 , 89 ]. Moreover, the Alamar Blue assay method is frequently used to assess the metabolic activity of proliferating cells: the active resazurin compound, upon entering living cells, is reduced to resorufin, a red fluorescent molecule that can be quantified [ 14 , 59 , 64 , 72 , 75 , 90 , 91 ].…”

“…The proliferative activity of cells cultured with the biomaterial can be determined based on the distribution of cells in the cell cycle and DNA synthesis. The colorimetric assay based on the bromodeoxyuridine/5-bromo-2′-deoxyuridine (BrdU) or 5-ethynyl-2’-deoxyuridine (EdU) incorporation during the S-phase of the cell cycle of growing cells is amply used [ 52 , 57 , 70 ]. The cell cycle can also be analyzed using commercial kits able to measure G0/G1, S, and G2/M phase distributions considering the different staining of cells with propidium iodide (PI) by flow cytometry [ 52 ].…”

“…They can proliferate and differentiate into osteoblasts upon appropriate stimuli. MSCs isolated from bone marrow are regarded as the gold standard [ 14 , 53 , 55 , 57 , 67 , 68 , 73 , 76 , 77 , 79 , 83 , 91 , 94 , 98 , 107 , 108 , 109 ]. MSC-like cells isolated from the stromal vascular fraction of the adipose tissue, namely, adipose-derived stem cells, ASC, are seldom used in selected applications [ 2 , 65 , 72 , 82 , 89 , 104 , 109 , 110 , 111 , 112 ].…”