Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 3 (4), 4342-4351

Chemically Treated 3D Printed Polymer Scaffolds for Biomineral Formation

Affiliations

Chemically Treated 3D Printed Polymer Scaffolds for Biomineral Formation

Richard J Jackson et al. ACS Omega.

Abstract

We present the synthesis of nylon-12 scaffolds by 3D printing and demonstrate their versatility as matrices for cell growth, differentiation, and biomineral formation. We demonstrate that the porous nature of the printed parts makes them ideal for the direct incorporation of preformed nanomaterials or material precursors, leading to nanocomposites with very different properties and environments for cell growth. Additives such as those derived from sources such as tetraethyl orthosilicate applied at a low temperature promote successful cell growth, due partly to the high surface area of the porous matrix. The incorporation of presynthesized iron oxide nanoparticles led to a material that showed rapid heating in response to an applied ac magnetic field, an excellent property for use in gene expression and, with further improvement, chemical-free sterilization. These methods also avoid changing polymer feedstocks and contaminating or even damaging commonly used selective laser sintering printers. The chemically treated 3D printed matrices presented herein have great potential for use in addressing current issues surrounding bone grafting, implants, and skeletal repair, and a wide variety of possible incorporated material combinations could impact many other areas.

Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
SLS schematic and process parameters.
Figure 2
Figure 2
Scheme of the work presented herein.
Figure 3
Figure 3
SLS-printed substrates: (a,b) spike arrays, (c) 96-well plate chamfered insert, (d) 2 mm thick plate, (e,f) human ear bones (ossicles, joined, 3× scale), and (g,h) hollow cube. Grid scale in millimeters.
Figure 4
Figure 4
Scanning electron micrographs of (a) 3D printed nylon-12 mesh showing the fractured macroporous structure and 3D printed nylon-12 framework treated with (b) a TiO2 sol, (c) titanium(IV) butoxide–TEOS mix, (d) titanium(IV) butoxide, (e) TEOS, and (f) (3-aminopropyl)triethoxysilane.
Figure 5
Figure 5
High-resolution XPS spectra of a 3D printed nylon-12 tablet treated with a 50:50 mixture of titanium(IV) butoxide and TEOS. (a) Ca 2p spectrum showing the sample before (bottom) and after (top) stem cell differentiation. Binding energy values of 347.2 eV for the Ca 2p3/2 and 352.7 eV for Ca 2p1/2 are in good agreement with the literature for hydroxyapatite (Ca10(PO4)6(OH)2) (60). (b) Corresponding P 2p spectrum with binding energy values of 133.1 eV (P 2p3/2) and 133.9 (P 2p1/2). (c) Si 2p high-resolution scan for the titanium(IV) butoxide and TEOS-treated tablet before (bottom) and after cell differentiation (top). The lower signal obtained after differentiation is attributed to the overgrowth of hydroxyapatite onto the substrate. (d) Ti 2p high-resolution spectra before (bottom) and after (top) cell differentiation.
Figure 6
Figure 6
CT images of treated and untreated 3D printed scaffolds, with grayscale values corresponding to their radiopacity in Hounsfield units (HU). (A) Three-dimensional volume rendered CT image showing increased surface radiopacity following treatment with TiO2, titanium(IV) butoxide, and TEOS–titanium(IV) butoxide coatings. TEOS and APTES-treated scaffolds show a radiopacity similar to that of the untreated material. (B) CT cross sections show that the chemical treatments are limited to the surface in the cases of TiO2, titanium(IV) butoxide, and TEOS–titanium(IV) butoxide, whereas TEOS and APTES are not detectable because of their radiopacity comparable to that of the untreated scaffolds. (C) CT signal intensity (HU) along a line horizontally bisecting the corresponding scaffolds shown above in (A,B).
Figure 7
Figure 7
Growth of mesenchymal stem cells (1000 per well) seeded onto the surface of 3D printed scaffolds modified with a range of chemical treatments. The points represent the mean of n = 6 independently seeded wells, and error bars show standard error of the mean. The light output corresponds to photon counts measured following the addition of bioluminescent substrate to the cells and indicates relative viable cell population size. Statistical analysis is presented in Table S2.
Figure 8
Figure 8
(a) Heating/cooling curve of a nylon-12 cube impregnated with 10 μL of EFH1 ferrofluid subjected to an ac magnetic field of a frequency of 930 kHz and a strength of 15 kA m–1, (b) photograph of the cube, (c) thermal image of the heated cube, and (d,e) water droplet on a nylon surface treated with titanium(IV) butoxide (d) and TEOS (e) showing the difference in surface wetting.

Similar articles

See all similar articles

Cited by 1 PubMed Central articles

References

    1. Muth J. T.; Vogt D. M.; Truby R. L.; Mengüç Y.; Kolesky D. B.; Wood R. J.; Lewis J. A. Embedded 3D printing of strain sensors within highly stretchable elastomers. Adv. Mater. 2014, 26, 6307–6312. 10.1002/adma.201400334. - DOI - PubMed
    1. Lee M.; Dunn J. C. Y.; Wu B. M. Scaffold fabrication by indirect three-dimensional printing. Biomaterials 2005, 26, 4281–4289. 10.1016/j.biomaterials.2004.10.040. - DOI - PubMed
    1. Moutos F. T.; Guilak F. Composite scaffolds for cartilage tissue engineering. Biorheology 2008, 45, 501–512. 10.3233/BIR-2008-0491. - DOI - PMC - PubMed
    1. Shen H.; Niu Y.; Hu X.; Yang F.; Wang S.; Wu D. A biomimetic 3D microtubule-orientated poly(lactide-co-glycolide) scaffold with interconnected pores for tissue engineering. J. Mater. Chem. B 2015, 3, 4417–4425. 10.1039/c5tb00167f. - DOI
    1. Frølich S.; Weaver J. C.; Dean M. N.; Birkedal H. Uncovering Nature’s Design Strategies through Parametric Modelling, Multi-Material 3D Printing, and Mechanical Testing. Adv. Eng. Mater. 2017, 19, e20160084810.1002/adem.201600848. - DOI
Feedback