HIF-1α expression in canine BMSCs after target gene transduction.

<p>mRNA and protein expression levels in the canine BMSCs transduced by Lenti-HIF, Lenti-cHIF and Lenti-GFP On days 0, 1, 4, 7, 14, and 21 (A and B).</p

Immunohistochemical analysis of new bone formation in each group in the subcutaneous nude mice.

<p>Immunostaining for GFP of (a) CMPC group, (b) Lenti-GFP group, (c) Lenti-HIF group, and (d) Lenti-cHIF group. The GFP, HIF, and cHIF groups show positive brown staining in fibroblastic-like tissue and bone matrix (red arrow). The strong HIF-1α expression was stained in both the bone and the surrounding fibroblastic-like tissue (red arrows) in (g) Lenti-HIF group and (h) Lenti-cHIF group. There was no obvious positive staining in (e) the CMPC group or (f) the Lenti-GFP group (a–h, 400×).</p

Histological analysis of newly formed bone and remnant scaffold area in calvarial defects.

<p>The specimens were sliced, and sections were stained with van Gieson's picrofuchsin. From top to bottom: Blank, CMPC construct, Lenti-GFP-transduced BMSCs/CMPC construct, Lenti-HIF-transduced BMSCs/CMPC construct, and Lenti-cHIF- transduced BMSCs/CMPC construct (F = fibroblastic-like tissue, C = CMPC, B = new bone, DI = dental implant; original magnification, 40×, 100×) (A). BIC per 40× field in histological sections (B). Bone density per 40× field in histological sections (C). The percentage of remnant scaffold area per 100× field in histological sections (D). (** <i>P</i><0.01, target gene groups compared with the GFP group, Blank group or CMPC group).</p

Characterization of F344 canine BMSCs and target gene transduction.

<p>Flow cytometry analysis of cell surface markers CD90, CD105, CD31, and CD34 (A); A multiplicity of infection of 7 pfu/cell achieved high transfer efficiency, around 90%, 4 days after Lenti-GFP, Lenti-HIF, and cHIF transduction of canine BMSCs (100×) (B).</p

Radiography and micro-CT evaluation of bone repair and osseointegration at 12 weeks after implantation.

<p>X-ray images were taken immediately after surgery and at 12 weeks (A-a). The morphology of the newly formed bone in the defects was reconstructed using micro-CT (A-b). Morphometric analysis of the BV/TV (B-a), BMD (B-b), Tb.N (B-c), and Tb.Th (B-d). (**, <i>P</i><0.01, the target gene groups compared to the blank group, the GFP group or the CMPC group).</p

New bone formation and mineralization determined histomorphometrically by TE, CA, and AL fluorescent quantification, which represent the mineralization level at 12 weeks after the operation (A).

<p>Parts a, b, c, d, and e are confocal laser scanning microscopy images for each group. Parts a4, b4, c4, d4, and e4 represent merged images of the three fluorochromes for the same group. Parts a5, b5, c5, d5, and e5 represent the merged images of the three fluorochromes together with the plain confocal laser microscopy image for the same group. (B) The graph shows the percentage of each fluorochrome area in each group. (** <i>P</i><0.01, target gene groups compared with the GFP group, Blank group or CMPC group; #, <i>P</i><0.05, the cHIF group compared to the HIF group).</p

Observation of subcutaneous ectopic osteogenesis in the nude mice.

<p>(A) The undecalcified specimens were stained with van Gieson's picrofuchsin. From top to bottom: CMPC construct, Lenti-GFP- transduced BMSC/CMPC construct, Lenti-HIF-transduced BMSC/CMPC construct, and Lenti-cHIF-transduced BMSC/CMPC construct (F = fibroblastic-like tissue, C = CMPC, B = new bone; 1.25×, 40×, and 100×). (B). New bone formation area per 100× field in histological sections. (C) The percentage of remnant scaffold area per 100× field in histological sections. (**, <i>P</i><0.01, the target gene groups compared to the GFP group or the CMPC group).</p

A pH-Responsive Yolk-Like Nanoplatform for Tumor Targeted Dual-Mode Magnetic Resonance Imaging and Chemotherapy

Incorporation of T₁ and T₂ contrast material in one nanosystem performing their respective MR contrast role and simultaneously serving as an efficient drug delivery system (DDS) has a significant potential application for clinical diagnosis and chemotherapy of cancer. However, inappropriate incorporation always encountered many issues, such as low contact area of T₁ contrast material with water-proton, inappropriate distance between T₂ contrast material and water molecule, and undesirable disturbance of T₂ contrast material for T₁ imaging. Those issues seriously limited the T₁ or T₂ contrast effect. In this work, we developed a yolk-like Fe₃O₄@Gd₂O₃ nanoplatform functionalized by polyethylene glycol and folic acid (FA), which could efficiently exert their tumor targeted T₁–T₂ dual-mode MR imaging and drug delivery role. First, this nanoplatform possessed a high longitudinal relaxation rate (<i>r</i>₁) (7.91 mM^–1 s^–1) and a stronger transverse relaxation rate (<i>r</i>₂) (386.5 mM^–1 s^–1) than that of original Fe₃O₄ (268.1 mM^–1 s^–1). Second, cisplatin could be efficiently loaded into this nanoplatform (112 mg/g) and showed pH-responsive release behavior. Third, this nanoplatform could be effectively internalized by HeLa cells with time and dosage dependence. Fourth, the FA receptor-mediated nanoplatform displayed excellent T₁–T₂ dual mode MR contrast enhancement and anticancer activity both <i>in vitro</i> and <i>in vivo</i>. Fifth, no apparent toxicity for vital organs was observed with systemic delivery of the nanoplatform <i>in vivo</i>. Thus, this nanoplatform could be a potential nanotheranostic for tumor targeted T₁–T₂ dual-mode MR imaging and chemotherapy