A Novel Nanoparticle-Enhanced Photoacoustic Stimulus for Bone Tissue Engineering

Abstract

In this study, we introduce a novel nanoparticle-enhanced biophysical stimulus based on the photoacoustic (PA) effect. We demonstrate that the PA effect differentiates bone marrow-derived marrow stromal cells (MSCs) grown on poly(lactic-co-glycolic acid) (PLGA) polymer films toward osteoblasts. We further show that the osteodifferentiation of the MSCs due to PA stimulation is significantly enhanced by the presence of single-walled carbon nanotubes (SWCNTs) in the polymer. MSCs, without the osteogenic culture supplements (0.01 M bglycerophosphate, 50 mg/L ascorbic acid, 10 -8 M dexamethasone), were seeded onto plain glass slides, glass slides coated with PLGA, or glass slides coated with SWCNT-PLGA films and photoacoustically stimulated by a 527 nm Nd:YLF pulse laser, with a 200 ns pulse duration, and 10 Hz pulse frequency for 10 min a day for 15 consecutive days. The study had four control groups; three baseline controls similar to the three experimental groups but without PA stimulation, and one positive control where MSCs were grown on glass slides without PA stimulation but with osteogenic culture supplements. The osteogenic differentiation of all the groups was evaluated using quantitative assays (alkaline phosphatase, calcium, osteopontin) and qualitative staining (alizarin red). After 15 days, the PA stimulated groups showed up to a 350% increase in calcium content when compared with the non-PA stimulated positive control. Further, within the PA stimulated group, the PLGA-SWCNT group had 130% higher calcium values than the PLGA film without SWCNTs. These results were further corroborated by the analysis of osteopontin secretion, alkaline phosphatase expression, and qualitative alizarin red staining of extracellular matrix calcification. The results indicate that PA stimulation holds promise for bone tissue engineering and that the nanomaterials which enhance the PA effect should allow the development of biophysical rather than biochemical strategies to induce osteoinductive properties into tissue engineering scaffolds.

Interactions of 1D- and 2D-Layered Inorganic Nanoparticles with Fibroblasts and Human Mesenchymal Stem Cells

“…Alizarin Red S stains extracellular calcium and is used as a marker for osteo-differentiation of stem cells [22,27]. Figure 5 shows representative images of MSCs stained with Alizarin Red S for calcium deposits after treatment with 0 (Control), 10, or 50 µg/ml of MSNPs or WSNTs for 24 h and incubation in osteogenic differentiation media for 14 days.…”

Porous three-dimensional carbon nanotube scaffolds for tissue engineering

“…Typically, carbon nanomaterial dispersed polymeric scaffolds have been investigated for biomedical applications [9, 52, 70–72], however, compared to these composite architectures, 3D all-carbon scaffolds may possess additional multifunctional attributes. The chemical, physical and electrical properties of these 3D CNT scaffolds could be exploited to develop stimulus responsive scaffolds to deliver drugs[19, 20], electroceuticals applications[73], non-invasively image the scaffolds to track tissue regeneration[74] and control the fate of progenitor cells [17, 18]. Therefore, in a true-sense, 3D macroporous all-carbon scaffolds may be exploited as multifunctional scaffolds for the next generation of tissue engineering and regenerative medicine applications.…”

“…Carbon nanomaterials such as fullerenes, carbon nanotubes and graphene exhibit excellent physiochemical properties such as high mechanical strength, and electrical conductivity as well as unique electromagnetic, opto-acoustic response, and thus, their multifunctional characteristics have been exploited for several biomedical applications such as bioimaging[14–16], stem cell applications[17, 18], drug and gene delivery[19, 20], and photodynamic therapy [21, 22]. They have also been incorporated into polymeric scaffolds as mechanical reinforcing agents [23, 24] or contrast agents [25] to improve non-invasive imaging of the structural properties and biological response of polymeric scaffolds (e.g.…”

Biomedical Applications of Photoacoustic Imaging with Exogenous Contrast Agents

“…Furthermore, it has been shown that daily PA excitation of native or SWNT-loaded MSCs facilitates differentiation of cells to osteoblasts. 20,92 There is also a wide array of therapeutic applications requiring implantation or insertion of metallic or other optically absorbing devices. During such procedures, localization is critical for ensuring appropriate delivery of the device.…”