[Short-term follow up of treatment effect using one-time one-abutment placement in implant restoration in 35 patients with single posterior teeth loss].

PURPOSE: To evaluate the effet of one-time one-abutment placement on peri-implant tissues. METHODS: Thirty-five patients with single posterior loss were collected, who received definitive abutment at the moment of implant placement. One day and after 1 year of implant loading, radiographic assessment of marginal bone level changes and clinical status of peri-implant soft tissues were conducted. Plaque index, pocket depth as well as sulcus bleeding index were assessed. RESULTS: During 1 year follow-up period after loading, no implant failure was observed. The mean marginal bone loss of implants were (0.225±0.113) mm mesially and (0.439±0.123) mm distally. Standard periodontal probes were used to measure plaque index, probing depth, and gingival crevicular bleeding index immediately after repair and 1 year later. CONCLUSIONS: In the posterior region, one-time one-abutment placement may better protect peri-implant tissues as an ideal treatment protocol.

Assessment of the osteogenic effect after maxillary sinus floor elevation and simultaneous implantation with or without bone grafts by analyzing trabecular bone parameters: a retrospective study.

OBJECTIVE: The aim of this population-based retrospective study was to compare the osteogenic effect of newly formed bone after maxillary sinus floor elevation (MSFE) and simultaneous implantation with or without bone grafts by quantitatively analyzing trabecular bone parameters. METHODOLOGY: A total of 100 patients with missing posterior maxillary teeth who required MSFE and implantation were included in this study. Patients were divided into two groups: the non-graft group (n=50) and the graft group (n=50). Radiographic parameters were measured using cone beam computed tomography (CBCT), and the quality of newly formed bone was analyzed by assessing trabecular bone parameters using CTAn (CTAnalyzer, SkyScan, Antwerp, Belgium) software. RESULTS: In the selected regions of interest, the non-graft group showed greater bone volume/total volume (BV/TV), bone surface/total volume (BS/TV), trabecular number (Tb. N), and trabecular thickness (Tb. Th) than the graft group (p<0.001). The non-graft group showed lower trabecular separation (Tb. Sp) than the graft group (p<0.001). The incidence of perforation and bleeding was higher in the graft group than in the non-graft group (p<0.001), but infection did not significantly differ between groups (p>0.05). Compared to the graft group, the non-graft group showed lower postoperative bone height, gained bone height and apical bone height (p<0.001). CONCLUSION: MSFE with and without bone grafts can significantly improve bone formation. In MSFE, the use of bone grafts hinders the formation of good quality bone, whereas the absence of bone grafts can generate good bone quality and limited bone mass.

Assessment of the osteogenic effect after maxillary sinus floor elevation and simultaneous implantation with or without bone grafts by analyzing trabecular bone parameters: a retrospective study

Abstract Objective: The aim of this population-based retrospective study was to compare the osteogenic effect of newly formed bone after maxillary sinus floor elevation (MSFE) and simultaneous implantation with or without bone grafts by quantitatively analyzing trabecular bone parameters. Methodology: A total of 100 patients with missing posterior maxillary teeth who required MSFE and implantation were included in this study. Patients were divided into two groups: the non-graft group (n=50) and the graft group (n=50). Radiographic parameters were measured using cone beam computed tomography (CBCT), and the quality of newly formed bone was analyzed by assessing trabecular bone parameters using CTAn (CTAnalyzer, SkyScan, Antwerp, Belgium) software. Results: In the selected regions of interest, the non-graft group showed greater bone volume/total volume (BV/TV), bone surface/total volume (BS/TV), trabecular number (Tb. N), and trabecular thickness (Tb. Th) than the graft group (p<0.001). The non-graft group showed lower trabecular separation (Tb. Sp) than the graft group (p<0.001). The incidence of perforation and bleeding was higher in the graft group than in the non-graft group (p<0.001), but infection did not significantly differ between groups (p>0.05). Compared to the graft group, the non-graft group showed lower postoperative bone height, gained bone height and apical bone height (p<0.001). Conclusion: MSFE with and without bone grafts can significantly improve bone formation. In MSFE, the use of bone grafts hinders the formation of good quality bone, whereas the absence of bone grafts can generate good bone quality and limited bone mass.

Designing nanohesives for rapid, universal, and robust hydrogel adhesion.

Nanoparticles-based glues have recently been shown with substantial potential for hydrogel adhesion. Nevertheless, the transformative advance in hydrogel-based application places great challenges on the rapidity, robustness, and universality of achieving hydrogel adhesion, which are rarely accommodated by existing nanoparticles-based glues. Herein, we design a type of nanohesives based on the modulation of hydrogel mechanics and the surface chemical activation of nanoparticles. The nanohesives can form robust hydrogel adhesion in seconds, to the surface of arbitrary engineering solids and biological tissues without any surface pre-treatments. A representative application of hydrogel machine demonstrates the tough and compliant adhesion between dynamic tissues and sensors via nanohesives, guaranteeing accurate and stable blood flow monitoring in vivo. Combined with their biocompatibility and inherent antimicrobial properties, the nanohesives provide a promising strategy in the field of hydrogel based engineering.

Influence of Er:YAG laser irradiation on the outcomes of alveolar ridge preservation at the infected molar sites: a randomized controlled trial.

BACKGROUND: The purpose of this study was to investigate the socket healing outcome after alveolar ridge preservation at infected molar sites using an erbium-doped yttrium aluminium garnet (Er:YAG) laser. METHODS: Eighteen patients who needed molar extraction and exhibited signs of infection were included and allocated into either the laser group or the control group. Er:YAG laser irradiation for degranulation and disinfection was performed with alveolar ridge preservation (ARP) in the laser group. Traditional debridement with a curette was performed in the control group. Two months after ARP, bone tissue samples were harvested at the time of implant placement for histological analysis. Assessment of dimension changes in alveolar bone was conducted by superimposing two cone-beam computed tomography (CBCT) scans taken at baseline and two months after extraction. RESULTS: Histologically, after two months of healing, Er:YAG laser treatment resulted in more newly formed bone (laser: 17.75 ± 8.75, control: 12.52 ± 4.99, p = 0.232). Moreover, greater osteocalcin (OCN) positive expression and lower runt-related transcription factor 2 (RUNX-2) positive expression were detected in the laser group. However, no statistically significant difference was observed between the two groups. The difference in the vertical resorption of the buccal bone plate was statistically significant between groups (laser: -0.31 ± 0.26 mm, control: -0.97 ± 0.32 mm, p < 0.05). Major changes in ridge width were observed at 1 mm below the bone crest. However, the differences between groups were not significant (laser: -0.36 ± 0.31 mm, control: -1.14 ± 1.24 mm, p = 0.171). CONCLUSIONS: ARP with Er:YAG laser irradiation seemed to improve bone healing by regulating osteogenesis-related factor expression in the early stage at infected sites. TRIAL REGISTRATION: The trial was registered on the Chinese Clinical Trial Registry Platform ( https://www.chictr.org.cn/ ) (registration number: ChiCTR2300068671; registration date: 27/02/2023).

Bioactive Nanocomposite Microsponges for Effective Reconstruction of Critical-Sized Calvarial Defects in Rat Model.

Introduction: Micro-sized sponge particulates have attracted extensive attention because of their potential to overcome the intrinsic limitations of conventional monolithic scaffolds in tissue engineering. Bioactive nanocomposite microsponges are regarded as potential bone substitute materials for bone regeneration. Methods: Based on a combination of microfluidic emulsion with further freezing and in situ thawing, chitosan (CS)-hydroxyapatite (HAP) microsponges were prepared and characterized in terms of their morphology and elemental distribution using a scanning electron microscope equipped with an X-ray detector. The swelling ratio, porosity, degradability, antibacterial activity, and bioactivity were detected and analyzed. The biological functions of the CS-HAP microsponges were examined to assess the adhesion, proliferation, and differentiation of in vitro co-cultured rat bone marrow mesenchymal stem cells (rBMSCs). Furthermore, the CS-HAP microsponges were used as cell-free scaffolds and implanted into calvarial defects in a rat model to evaluate the in vivo osteogenesis. Results: The CS-HAP microsponges have a porous structure with high porosity (~76%), good swelling capacity (~1900%), and shape-memory properties. The results of in vitro experiments show that the CS-HAP microsponges achieve good bioactivity and promote osteogenic differentiation of rBMSCs. Furthermore, the CS-HAP microsponges significantly promote bone regeneration in rat calvarial defects. Conclusion: The bioactive CS-HAP microsponges have the potential to be used as bone substitute materials for bone tissue engineering.

A review of biomimetic scaffolds for bone regeneration: Toward a cell-free strategy.

In clinical terms, bone grafting currently involves the application of autogenous, allogeneic, or xenogeneic bone grafts, as well as natural or artificially synthesized materials, such as polymers, bioceramics, and other composites. Many of these are associated with limitations. The ideal scaffold for bone tissue engineering should provide mechanical support while promoting osteogenesis, osteoconduction, and even osteoinduction. There are various structural complications and engineering difficulties to be considered. Here, we describe the biomimetic possibilities of the modification of natural or synthetic materials through physical and chemical design to facilitate bone tissue repair. This review summarizes recent progresses in the strategies for constructing biomimetic scaffolds, including ion-functionalized scaffolds, decellularized extracellular matrix scaffolds, and micro- and nano-scale biomimetic scaffold structures, as well as reactive scaffolds induced by physical factors, and other acellular scaffolds. The fabrication techniques for these scaffolds, along with current strategies in clinical bone repair, are described. The developments in each category are discussed in terms of the connection between the scaffold materials and tissue repair, as well as the interactions with endogenous cells. As the advances in bone tissue engineering move toward application in the clinical setting, the demonstration of the therapeutic efficacy of these novel scaffold designs is critical.

Effects of Androgen Receptor Overexpression on Chondrogenic Ability of Rabbit Articular Chondrocytes

BACKGROUND@#The role of sex hormones and their receptors has drawn much attention in the process of cartilage regeneration. This study aimed to investigate the effect of androgen receptor (AR) on the chondrogenic ability of articular chondrocytes and the related mechanism. @*METHODS@#Articular chondrocytes were isolated, cultured, identified by toluidine blue staining and then transduced with lentivirus carrying the AR gene. The cell viability was determined using Cell Counting Kit-8, and cell apoptosis was assessed by flow cytometry analysis. The effects of AR overexpression on the expression of cartilage-specific proteins and some signalling molecules were evaluated by real-time PCR and Western blotting. Using 24 New Zealand rabbits, the regeneration of rabbit articular cartilage defects was further investigated in vivo and evaluated histologically. @*RESULTS@#The overexpression of AR significantly reduced the apoptosis rate of chondrocytes but did not affect their proliferation. The overexpression of AR also promoted the expression of Sry-related HMG box 9, collagen II and aggrecan, decreased the expression of matrix metalloproteinase-13, and downregulated p-S6 and RICTOR. The experimental group with AR-overexpressing chondrocytes exhibited superior regeneration of cartilage defects. @*CONCLUSION@#AR overexpression can maintain the phenotype of chondrocytes and promote chondrogenesis in vitro and in vivo. mTOR-related signalling was inhibited.

Effects of Androgen Receptor Overexpression on Chondrogenic Ability of Rabbit Articular Chondrocytes

BACKGROUND@#The role of sex hormones and their receptors has drawn much attention in the process of cartilage regeneration. This study aimed to investigate the effect of androgen receptor (AR) on the chondrogenic ability of articular chondrocytes and the related mechanism. @*METHODS@#Articular chondrocytes were isolated, cultured, identified by toluidine blue staining and then transduced with lentivirus carrying the AR gene. The cell viability was determined using Cell Counting Kit-8, and cell apoptosis was assessed by flow cytometry analysis. The effects of AR overexpression on the expression of cartilage-specific proteins and some signalling molecules were evaluated by real-time PCR and Western blotting. Using 24 New Zealand rabbits, the regeneration of rabbit articular cartilage defects was further investigated in vivo and evaluated histologically. @*RESULTS@#The overexpression of AR significantly reduced the apoptosis rate of chondrocytes but did not affect their proliferation. The overexpression of AR also promoted the expression of Sry-related HMG box 9, collagen II and aggrecan, decreased the expression of matrix metalloproteinase-13, and downregulated p-S6 and RICTOR. The experimental group with AR-overexpressing chondrocytes exhibited superior regeneration of cartilage defects. @*CONCLUSION@#AR overexpression can maintain the phenotype of chondrocytes and promote chondrogenesis in vitro and in vivo. mTOR-related signalling was inhibited.

Comparison of the differentiation of dental pulp stem cells and periodontal ligament stem cells into neuron-like cells and their effects on focal cerebral ischemia.

Recent studies have reported an increasing incidence of ischemic stroke, particularly in younger age groups. Dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) are the most common stem cells acquired from the teeth of adults, even elderly people. However, there are no detailed reports on whether DPSCs or PDLSCs are suitable for the treatment of ischemic stroke. In this study, the in vitro differentiation of DPSCs and PDLSCs into neuron-like cells was evaluated. Then, we established a rat model of cerebral ischemia. DPSCs or PDLSCs were administered to animals, and the therapeutic effects of these two types of cells were investigated. The results showed that PDLSCs had a higher differentiation rate than DPSCs. Immunofluorescence studies showed that the expression of the neuronal differentiation marker Thy-1 was higher in PDLSCs than in DPSCs, and other gene markers of neuronal differentiation showed corresponding trends, which were confirmed by western blot analysis. In this process, the Notch and Wnt signaling pathways were inhibited and activated, respectively. Finally, rats with transient occlusion of the right middle cerebral artery were used as a model to assess the therapeutic effect of PDLSCs and DPSCs on ischemia. The results showed that rats in the PDLSC-treated group emitted significantly greater red fluorescence signal than the DPSC-treated group. PDLSC transplantation promoted the recovery of neurological function more effectively than DPSC transplantation. Hence, PDLSCs represent an autogenous source of adult mesenchymal stem cells with desirable biological properties and may be an ideal candidate for clinical applications.

Clinical effect of platelet-rich fibrin combined with bone substitute in alveolar ridge preservation / 口腔疾病防治

Objective@#To study the clinical outcomes of implanting platelet rich fibrinogen (PRF) mixed with Bio-Oss® in the extraction socket for alveolar ridge preservation and to provide evidence for clinical application. @*Methods@#Thirty-six patients who underwent alveolar ridge preservation were enrolled. Thirty-six extraction sites were divided into two groups: PRF mixed with Bio-Oss® group (test group) and Bio-Oss® alone (control group). Bone dimensional changes in height and width were measured by CBCT before and 6 months after surgery, and early soft tissue healing and postoperative pain sensation were evaluated clinically 1 week after surgery.@* Results @# There was no significant difference in the alveolar bone height (-1.48 ± 0.40) mm between the test group and the control group. The difference in the alveolar bone width between the test group (-1.09 ± 0.42) mm and the control group (-1.35 ± 0.22) mm was statistically significant (z=-2.63, P=0.01). The postoperative pain score of the test group was 2.39 ± 1.20, and that of the control group was 3.39 ± 1.65, the difference was statistically significant (t=-2.083, P=0.045). There was no significant difference in soft tissue healing between the test group and the control group.@*Conclusion @#The use of PRF mixed with Bio-Oss ®in the alveolar ridge preservation procedure can reduce alveolar bone absorption and postoperative pain.

Strategies for derivation of endothelial lineages from human stem cells.

Accumulating evidence demonstrates that pre-vascularization of tissue-engineered constructs can significantly enhance their survival and engraftment upon transplantation. Endothelial cells (ECs), the basic component of vasculatures, are indispensable to the entire process of pre-vascularization. However, the source of ECs still poses an issue. Recent studies confirmed that diverse approaches are available in the derivation of ECs for tissue engineering, such as direct isolation of autologous ECs, reprogramming of somatic cells, and induced differentiation of stem cells in typology. Herein, we discussed a variety of human stem cells (i.e., totipotent, pluripotent, multipotent, oligopotent, and unipotent stem cells), which can be induced to differentiate into ECs and reviewed the multifarious approaches for EC generation, such as 3D EB formation for embryonic stem cells (ESCs), stem cell-somatic cell co-culture, and directed endothelial differentiation with growth factors in conventional 2D culture.

R.T.R® promotes bone marrow mesenchymal stem cells osteogenic differentiation by upregulating BMPs/SMAD induced cbfa1 expression.

Bone marrow mesenchymal stem cells (BMSCs) of rats were isolated and Bio-Oss® and R.T.R® materials were used in this study.Alkaline phosphatase (ALP) activity in each group was calculated. The ability of adhesion and proliferation of BMSCs on Bio-Oss® and R.T.R® increased with time, but they were significantly higher on R.T.R® than that of Bio-Oss® at all time points (p<0.05). Compared with Bio-Oss®, R.T.R® could promote the expression and activity of ALP in BMSCs, and the expression of bone formation related transcription factors bone morphogenetic protein-1 (BMP-1), Cbfa1 and osteoblast marker genes ALP, collagen I, osteopontin, osseomucin and osteocalcin. The expression levels of cbfa1, ALP, collagen I, osteopontin, osseomucin and osteocalcin were inhibited after downregulated expression of BMP-1 in BMSCs and inoculation with R.T.R®. R.T.R® could up-regulate BMP-1 expression and cbfa1 expression through BMPs/SMAD signaling pathway, thereby promoting the expression of ALP, collagen I, osteopontin, osseomucin and osteocalcin and promoting osteoblast differentiation.

Superhero Rictor promotes cellular differentiation of mouse embryonic stem cells.

Embryonic stem cells (ESCs) hold great promise for regenerative medicine. To harness the full therapeutic potential of ESCs, better understanding of the molecular mechanisms underlying the maintenance and differentiation of ESCs is required. Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that integrates growth factor receptor signaling with cellular growth and proliferation. Dysregulation of mTOR signaling has been linked to various human diseases including cancer and metabolic syndromes. However, little is known regarding the function of mTOR signaling in the regulation of ES cell differentiation. Here we report that Rictor, a key component of mTORC2, functions as a novel ES cell differentiation promoting factor. Mechanistically, Rictor is able to interact with Prkch and facilitate Prkch phosphorylation at Ser-642. Upon phosphorylation, Prkch promotes Klf4 phosphorylation and inhibits Klf4-dependent E-cadherin expression, thereafter leading to the ES cell differentiation. These findings reveal a novel Rictor-Prkch-Klf4 pathway that plays an important role in the regulation of ES cell differentiation.

Clinical effect of titanium-zirconium small-diameter implants in the anterior esthetic zone / 口腔疾病防治

Objective@#To investigate the clinical effect of a titanium-zirconium small-diameter implant in anterior teeth with bone deficiencies in the esthetic area and to provide a basis for clinical application of this implant. @* Methods @# A retrospective analysis was performed using clinical data from 30 patients with a missing alveolar ridge width < 5.5 mm and a titanium-zirconium 3.3 mm diameter implant prosthesis in the anterior esthetic region. A total of 38 titanium-zirconium implants with a diameter of 3.3 mm were implanted in 30 patients. Clinical examination and CBCT were performed 12 and 24 months after implantation to evaluate the success rate and marginal bone resorption of the 3.3 mm small-diameter titanium-zirconium implants. The modified plaque index, improved gingival sulcus bleeding index, exploration depth, pink esthetic score (PES) and prosthetic complications were measured and recorded.@*Results @#The 24-month success rate of the implant was 100%. The average marginal bone resorption height was 0.51 ± 0.20 mm at 12 months after implant placement and 0.59 ± 0.18 mm at 24 months. The edge bone height did not change significantly (t=1.381, P=0.178). No significant differences were found in the modified plaque index around the implant, modified sulcus bleeding index and probing depth between 12 and 24 months (P > 0.05), and the gingival health was good. The PES value was 9.77 ± 1.48 at 12 months and 10.77 ± 1.50 at 24 months (t=0.426, P=0.672). The PES was increased at 24 months versus 12 months, but this difference was not significant (P > 0.05). The overall esthetic effect was good, and no complications occurred after repair.@*Conclusion@# Titanium-zirconium small-diameter implants can achieve good short-term clinical results in the esthetic area of the anterior teeth.

Functional reconstruction of critical-sized load-bearing bone defects using a Sclerostin-targeting miR-210-3p-based construct to enhance osteogenic activity.

A considerable amount of research has focused on improving regenerative therapy strategies for repairing defects in load-bearing bones. The enhancement of tissue regeneration with microRNAs (miRNAs) is being developed because miRNAs can simultaneously regulate multiple signaling pathways in an endogenous manner. In this study, we developed a miR-210-based bone repair strategy. We identified a miRNA (miR-210-3p) that can simultaneously up-regulate the expression of multiple key osteogenic genes in vitro. This process resulted in enhanced bone formation in a subcutaneous mouse model with a miR-210-3p/poly-l-lactic acid (PLLA)/bone marrow-derived stem cell (BMSC) construct. Furthermore, we constructed a model of critical-sized load-bearing bone defects and implanted a miR-210-3p/ß-tricalcium phosphate (ß-TCP)/bone mesenchymal stem cell (BMSC) construct into the defect. We found that the load-bearing defect was almost fully repaired using the miR-210-3p construct. We also identified a new mechanism by which miR-210-3p regulates Sclerostin protein levels. This miRNA-based strategy may yield novel therapeutic methods for the treatment of regenerative defects in vital load-bearing bones by utilizing miRNA therapy for tissue engineering. STATEMENT OF SIGNIFICANCE: The destroyed maxillofacial bone reconstruction is still a real challenge for maxillofacial surgeon, due to that functional bone reconstruction involved load-bearing. Base on the above problem, this paper developed a novel miR-210-3p/ß-tricalcium phosphate (TCP)/bone marrow-derived stem cell (BMSC) construct (miR-210-3p/ß-TCP/BMSCs), which lead to functional reconstruction of critical-size mandible bone defect. We found that the load-bearing defect was almost fully repaired using the miR-210-3p construct. In addition, we also found the mechanism of how the delivered microRNA activated the signaling pathways of endogenous stem cells, leading to the defect regeneration. This miRNA-based strategy can be used to regenerate defects in vital load-bearing bones, thus addressing a critical challenge in regenerative medicine by utilizing miRNA therapy for tissue engineering.

A tailored nanosheet decorated with a metallized dendrimer for angiography and magnetic resonance imaging-guided combined chemotherapy.

Considering the chemical exchange between gadolinium centers and water protons, nanosystems comprising gadolinium conjugated with high specific area nanocarriers might serve as more robust clinical tools for diagnosis and imaging-guided therapy. Herein, a pH-responsive nanosystem containing graphene oxide conjugated with a folic acid- and gadolinium-labeled dendrimer (FA-GCGLD) to boost its T1 contrast ability was developed, and doxorubicin (DOX) and colchicine (COLC) were efficiently loaded onto this nanosystem (FA-GCGLD-DOX/COLC). This nanosystem showed a prominent T1 contrast with an ultrahigh relaxivity of up to 11.6 mM-1 s-1 and pH-responsive drug release behavior. HepG2 cells treated with FA-GCGLD-DOX/COLC were efficiently inhibited, and the cell contrast was enhanced. In vivo, the tumor accumulation of FA-GCGLD-DOX/COLC significantly increased, thereby facilitating the systemic delivery of particles and exerting tumor growth inhibition and an enhanced tumor contrast effect. Moreover, compared to free drugs, FA-GCGLD-DOX/COLC effectively decreased the drug resistance of the tumor, thereby improving the cancer chemotherapeutic efficacy. In addition, injecting rats with FA-GCGLD afforded excellent magnetic resonance angiography (MRA) images with high-resolution vascular structures because of the long blood circulation time of FA-GCGLD. Thus, this study provides a powerful tool for diverse applications in the biomedical field, including accurate diagnosis and chemotherapy of tumors and the detection of cardiovascular diseases.

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 (r1) (7.91 mM-1 s-1) and a stronger transverse relaxation rate (r2) (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 in vitro and in vivo. Fifth, no apparent toxicity for vital organs was observed with systemic delivery of the nanoplatform in vivo. Thus, this nanoplatform could be a potential nanotheranostic for tumor targeted T1-T2 dual-mode MR imaging and chemotherapy.

Iron oxide nanoclusters for T 1 magnetic resonance imaging of non-human primates.

Iron-oxide-based contrast agents for magnetic resonance imaging (MRI) had been clinically approved in the United States and Europe, yet most of these nanoparticle products were discontinued owing to failures to meet rigorous clinical requirements. Significant advances have been made in the synthesis of magnetic nanoparticles and their biomedical applications, but several major challenges remain for their clinical translation, in particular large-scale and reproducible synthesis, systematic toxicity assessment, and their preclinical evaluation in MRI of large animals. Here, we report the results of a toxicity study of iron oxide nanoclusters of uniform size in large animal models, including beagle dogs and the more clinically relevant macaques. We also show that iron oxide nanoclusters can be used as T 1 MRI contrast agents for high-resolution magnetic resonance angiography in beagle dogs and macaques, and that dynamic MRI enables the detection of cerebral ischaemia in these large animals. Iron oxide nanoclusters show clinical potential as next-generation MRI contrast agents.