Implants that serve simultaneously as an osteoconductive matrix and as a device for local growth factor delivery may be required for optimal bone regeneration in some applications. In the present study, hollow hydroxyapatite (HA) microspheres (106-150μm) in the form of three-dimensional (3-D) scaffolds or individual (loose) microspheres were created using a glass conversion process. The capacity of the implants, with or without transforming growth factor β1 (TGF-β1), to regenerate bone in a rat calvarial defect model was compared. The 3-D scaffolds supported the proliferation and alkaline phosphatase activity of osteogenic MLO-A5 cells in vitro, showing their cytocompatibility. Release of TGF-β1 from the 3-D scaffolds into phosphate-buffered saline ceased after 2-3 days when ∼30% of the growth factor was released. Bone regeneration in the 3-D scaffolds and the individual microspheres increased with time from 6 to 12 weeks, but it was significantly higher (23%) in the individual microspheres than in the 3-D scaffolds (15%) after 12 weeks. Loading with TGF-β1 (5μg per defect) enhanced bone regeneration in the 3-D scaffolds and individual microspheres after 6 weeks, but had little effect after 12 weeks. 3-D scaffolds and individual microspheres with larger HA diameter (150-250μm) showed better ability to regenerate bone. Based on these results, implants composed of hollow HA microspheres show promising potential as an osteoconductive matrix for local growth factor delivery in bone regeneration.
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http://dx.doi.org/10.1016/j.actbio.2012.11.017 | DOI Listing |
Org Lett
January 2025
Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan.
Decyanation after α-functionalization by exploiting the inherent properties of cyano groups enables the strategic assembly of a carbon scaffold. Herein, we demonstrate an amine-ligated boryl radical-mediated cyano group transfer (CGT) strategy of malononitriles under photocatalytic conditions. This strategy allows for the cleavage of C(sp)-CN and the formation of C(sp)-D and C(sp) to realize decyanative deuteration and cyclization via radical-polar crossover.
View Article and Find Full Text PDFBiomater Sci
January 2025
Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.
: To explore the relationship between the stability of poly(gamma-glutamic acid) (γ-PGA) dispersion systems with γ-PGA of different molecular weights (MWs) and concentrations and type I collagen mineralization. : γ-PGA was used as a noncollagenous protein (NCP) analogue to regulate the stability of supersaturated γ-PGA-stabilized amorphous calcium phosphate (PGA-ACP) solutions by changing the γ-PGA MW (2, 10, 100, 200 and 500 kDa) and concentration (400, 500 and 600 μg mL). Then, the optical density (OD) at 72 h was measured to determine the PGA-ACP solution stability.
View Article and Find Full Text PDFChem Biodivers
December 2024
Faculty of Medicine, Department of Chemistry, University of Niš, Niš, Serbia.
The thieno[2,3-d]pyrimidine fragment is in the structure of many drug-like candidate derivatives with a wide range of biological activities. However, very few dipeptidyl peptidase-4 (DPP-4) inhibitors with this building block are currently known. Here, the selection of a novel DPP-4 inhibitor based on the thienopyrimidine scaffold is reported.
View Article and Find Full Text PDFAm J Physiol Endocrinol Metab
January 2025
Exercise Physiology Laboratory, Department of Integrative Biology, University of California, Berkeley, California, United States.
The lactate shuttle concept has revolutionized our understanding and study of metabolism in physiology, biochemistry, intermediary metabolism, nutrition, and medicine. Seminal findings of the mitochondrial lactate oxidation complex (mLOC) elucidated the architectural structure of its components. Here, we report that the mitochondrial pyruvate carrier (mPC) is an additional member of the mLOC in mouse muscle and C2C12 myoblasts and myotubes.
View Article and Find Full Text PDFDespite their recognized potential for ischemic tissue repair, the clinical use of human mesenchymal stromal cells (hMSC) is limited by the poor viability of cells after injection and the variability of their paracrine function. In this study, we show how the choice of biomaterial scaffolds and the addition of cell preconditioning treatment can address these limitations and establish a proof-of-concept for cryopreservable hMSC-loaded microbeads. Injectable microbeads in chitosan, chitosan-gelatin, and alginate were produced using stirred emulsification to obtain a similar volume moment mean diameter (D[4,3] ∼ 500 µm).
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