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Lipid Coated Microbubbles and Low Intensity Pulsed Ultrasound Enhance Chondrogenesis of Human Mesenchymal Stem Cells in 3D Printed Scaffolds

View Article: PubMed Central - PubMed

ABSTRACT

Lipid-coated microbubbles are used to enhance ultrasound imaging and drug delivery. Here we apply these microbubbles along with low intensity pulsed ultrasound (LIPUS) for the first time to enhance proliferation and chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in a 3D printed poly-(ethylene glycol)-diacrylate (PEG-DA) hydrogel scaffold. The hMSC proliferation increased up to 40% after 5 days of culture in the presence of 0.5% (v/v) microbubbles and LIPUS in contrast to 18% with LIPUS alone. We systematically varied the acoustic excitation parameters—excitation intensity, frequency and duty cycle—to find 30 mW/cm2, 1.5 MHz and 20% duty cycle to be optimal for hMSC proliferation. A 3-week chondrogenic differentiation results demonstrated that combining LIPUS with microbubbles enhanced glycosaminoglycan (GAG) production by 17% (5% with LIPUS alone), and type II collagen production by 78% (44% by LIPUS alone). Therefore, integrating LIPUS and microbubbles appears to be a promising strategy for enhanced hMSC growth and chondrogenic differentiation, which are critical components for cartilage regeneration. The results offer possibilities of novel applications of microbubbles, already clinically approved for contrast enhanced ultrasound imaging, in tissue engineering.

No MeSH data available.


(a) A schematic of stereolithagraphy based 3D printer, (b,c) SEM micrographs of 3D printed cartilage scaffolds with square channels. The scale bar represents 200 μm.
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f1: (a) A schematic of stereolithagraphy based 3D printer, (b,c) SEM micrographs of 3D printed cartilage scaffolds with square channels. The scale bar represents 200 μm.

Mentions: Figure 1(a) shows a schematic representation of the 3D printer described in section 4.1. A scanning electron microscope (SEM, Zeiss NVision 40FIB) was employed to assess the matrix morphology and pore size. Typical SEM images of 3D-printed scaffolds with square pore shapes are presented in Fig. 1(b,c). Using Image J software (imagej.nih.gov), the pore dimension was found to be 700 × 690 μm2. The porosity of the scaffold was 49%. We calculated the porosity by measuring its solid phase density as well as apparent mass density according to49. All the measurements were repeated 6 times from different positions of the printed scaffolds.


Lipid Coated Microbubbles and Low Intensity Pulsed Ultrasound Enhance Chondrogenesis of Human Mesenchymal Stem Cells in 3D Printed Scaffolds
(a) A schematic of stereolithagraphy based 3D printer, (b,c) SEM micrographs of 3D printed cartilage scaffolds with square channels. The scale bar represents 200 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121887&req=5

f1: (a) A schematic of stereolithagraphy based 3D printer, (b,c) SEM micrographs of 3D printed cartilage scaffolds with square channels. The scale bar represents 200 μm.
Mentions: Figure 1(a) shows a schematic representation of the 3D printer described in section 4.1. A scanning electron microscope (SEM, Zeiss NVision 40FIB) was employed to assess the matrix morphology and pore size. Typical SEM images of 3D-printed scaffolds with square pore shapes are presented in Fig. 1(b,c). Using Image J software (imagej.nih.gov), the pore dimension was found to be 700 × 690 μm2. The porosity of the scaffold was 49%. We calculated the porosity by measuring its solid phase density as well as apparent mass density according to49. All the measurements were repeated 6 times from different positions of the printed scaffolds.

View Article: PubMed Central - PubMed

ABSTRACT

Lipid-coated microbubbles are used to enhance ultrasound imaging and drug delivery. Here we apply these microbubbles along with low intensity pulsed ultrasound (LIPUS) for the first time to enhance proliferation and chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in a 3D printed poly-(ethylene glycol)-diacrylate (PEG-DA) hydrogel scaffold. The hMSC proliferation increased up to 40% after 5 days of culture in the presence of 0.5% (v/v) microbubbles and LIPUS in contrast to 18% with LIPUS alone. We systematically varied the acoustic excitation parameters—excitation intensity, frequency and duty cycle—to find 30 mW/cm2, 1.5 MHz and 20% duty cycle to be optimal for hMSC proliferation. A 3-week chondrogenic differentiation results demonstrated that combining LIPUS with microbubbles enhanced glycosaminoglycan (GAG) production by 17% (5% with LIPUS alone), and type II collagen production by 78% (44% by LIPUS alone). Therefore, integrating LIPUS and microbubbles appears to be a promising strategy for enhanced hMSC growth and chondrogenic differentiation, which are critical components for cartilage regeneration. The results offer possibilities of novel applications of microbubbles, already clinically approved for contrast enhanced ultrasound imaging, in tissue engineering.

No MeSH data available.