Differential effects of nanoselenium doping on healthy and cancerous osteoblasts in coculture on titanium

Abstract

In the present study, selenium (Se) nanoclusters were grown through heterogeneous nucleation on titanium (Ti) surfaces, a common orthopedic implant material. Normal healthy osteoblasts (bone-forming cells) and cancerous osteoblasts (osteosarcoma) were cultured on the Se-doped surfaces having three different coating densities. For the first time, it is shown that substrates with Se nanoclusters promote normal osteoblast proliferation and inhibit cancerous osteoblast growth in both separate (mono-culture) and coculture experiment. This study suggests that Se surface nanoclusters can be properly engineered to inhibit bone cancer growth while simultaneously promoting the growth of normal bone tissue.

Keywords: biomaterials; bone cancer; coating; nanotechnology; orthopedics; selenium.

Figure 1

Representative SEM images of uncoated Ti A) and Se-coated Ti with low B) medium C) or high D) doses of Se nanoclusters. Note: Scale bars are 500 nm. Abbreviations: Se, selenium; SEM, standard error of mean; Ti, titanium.

Figure 2

Water contact angles on the uncoated and Se-coated Ti substrates. Contact angles increased on the substrates coated with selenium nanoclusters. Notes: Data = mean ± SEM; N = 3; *P < 0.05 compared to all the coated substrates. There was no significant difference among the contact angles on the coated substrates. Abbreviations: Se, selenium; SEM, standard error of mean; Ti, titanium.

Figure 3

Normal osteoblast densities increased on Se-coated Ti substrates after three days of culture. Notes: Data = mean ± SEM; N = 3; *P < 0.05 compared to uTi. Abbreviations: Se, selenium; SEM, standard error of mean; Ti, titanium; uTi, uncoated Ti.

Figure 4

Fluorescence microscopy images of normal healthy osteoblasts stained with DAPI after three days of culture on uTi A) Low-nSe-Ti B) Medium-nSe-Ti C) and High-nSe-Ti D) Scale bars are 100 μm. Abbreviations: DAPI, ; Se, selenium; SEM, standard error of mean; Ti, titanium; uTi, uncoated Ti.

Figure 5

Decreased cancerous osteoblast densities on the Se-coated substrates after three days of culture. Notes: Data = mean ± SEM; N = 3; *P < 0.01 compared to uTi; **P < 0.01 compared to Low-nSe-Ti; ***P < 0.05 compared to Medium-nSe-Ti. Abbreviations: Se, selenium; SEM, standard error of mean; Ti, titanium.

Figure 6

Fluorescence microscopy images of cancerous osteoblasts stained with DAPI after three days of culture on uTi A) Low-nSe-Ti B) Medium-nSe-Ti C) and High-nSe-Ti D). Note: Scale bars are 100 μm. Abbreviations: DAPI, ; Se, selenium; SEM, standard error of mean; Ti, titanium.

Figure 7

Increased cancerous osteoblast density after 65 hours of coculturing cancerous and healthy osteoblasts on uncoated Ti. Healthy osteoblast densities showed no significant change on uncoated Ti. Notes: Data = mean ± SEM; N = 3. Abbreviations: Se, selenium; SEM, standard error of mean; Ti, titanium.

Figure 8

Increased healthy osteoblast density after 53 and 65 hours of coculturing cancerous and healthy osteoblasts on High-nSe-Ti. Cancerous osteoblasts did not show any significant difference in density on Se-coated Ti. Notes: Data = mean ± SEM; N = 3. Abbreviations: Se, selenium; SEM, standard error of mean; Ti, titanium.