DNA Origami-Anthraquinone Hybrid Nanostructures for In Vivo Quantitative Monitoring of the Progression of Tumor Hypoxia Affected by Chemotherapy.

Hypoxia is a well-known feature of malignant solid tumors. To explain the misinterpretation of tumor hypoxia variation during chemotherapy, we developed a DNA origami-based theranostic nanoplatform with an intercalated anticancer anthraquinone as both the chemotherapeutic drug and the photoacoustic contrast agent. The size distribution of the DNA origami nanostructure is 44.5 ± 2.3 nm, whereas the encapsulation efficiency of the drug is 90.7 ± 1.0%, and the drug loading content is 92.2 ± 0.1%. The controlled cumulative release rates were measured in vitro, showing an acidic environment induced rapid drug release. The values of free energy of binding between the drugs and the DNA double helix were calculated through molecular simulations. The cell viability assay was used to characterize cytotoxicity, and fluorescence confocal cell imaging illustrates the biodistribution of the probe in vitro. Photoacoustic and fluorescence imaging were used to indicate drug delivery, release, and biodistribution to predict the drug's chemotherapeutic effect in vivo, whereas the photoacoustic signals were compared with those of deoxygenated/oxygenated hemoglobin to represent the tissue hypoxia/normoxia maps during the chemotherapeutic process and indicate alleviated tumor hypoxia. Staining of tissue sections taken from organs and tumors was used to verify the results of photoacoustic imaging. Our results suggest that photoacoustic imaging can visualize this DNA origami-based theranostic nanoplatform and reveal the mechanisms of chemotherapy on tumor hypoxia.

Tannic acid modified graphene/CNT three-dimensional conductive network for preparing high-performance transparent flexible heaters.

In this paper, the eco-friendly plant polyphenol, tannic acid (TA) was demonstrated as a non-covalent modifier for carbon nanotubes (CNTs), as well as a stripping medium to achieve exfoliated graphite to graphene by microfluidization. High-performance transparent flexible heater (TFH) with an embedded structure had been successfully fabricated by integrating conductive nanocomposites (TA-functionalized grapheme/TA-functionalized CNT/PEDOT:PSS; TG/TCNT/PEDOT) into waterborne polyurethane (WPU) film. Such a film exhibited favorable optical transmittance and sheet resistance (T = ca. 80% at 550 nm, Rs = 62.5 Ω/sq.), low root mean square (rms) roughness (approximately 0.37 nm), excellent adhesion and mechanical stability (the sheet resistance remained almost constant after 1000 bending cycle test for the bending radius of 10 mm), which are ideal as transparent heaters with high thermal efficiency. For TG/TCNT/PEDOT-WPU TFHs, the temperature increased rapidly and reached a steady state within 20 s with the maximum temperature reached to 116 °C, when the applied voltage was 20 V. Moreover, no variation in temperature was observed after the repeated heating-cooling tests and long-time stability test, indicating that TG/TCNT/PEDOT-WPU TCFs can be used as high performance TFHs. These TFH's are expected to be suitable for vehicle defrosting, smart windows, portable heating, smart wearable devices, etc.

Manganese Oxide Nanoparticles As MRI Contrast Agents In Tumor Multimodal Imaging And Therapy.

Contrast agents (CAs) play a crucial role in high-quality magnetic resonance imaging (MRI) applications. At present, as a result of the Gd-based CAs which are associated with renal fibrosis as well as the inherent dark imaging characteristics of superparamagnetic iron oxide nanoparticles, Mn-based CAs which have a good biocompatibility and bright images are considered ideal for MRI. In addition, manganese oxide nanoparticles (MONs, such as MnO, MnO2, Mn3O4, and MnOx) have attracted attention as T1-weighted magnetic resonance CAs due to the short circulation time of Mn(II) ion chelate and the size-controlled circulation time of colloidal nanoparticles. In this review, recent advances in the use of MONs as MRI contrast agents for tumor detection and diagnosis are reported, as are the advances in in vivo toxicity, distribution and tumor microenvironment-responsive enhanced tumor chemotherapy and radiotherapy as well as photothermal and photodynamic therapies.

Biomimetic polyurethane/TiO2 nanocomposite scaffolds capable of promoting biomineralization and mesenchymal stem cell proliferation.

Scaffolds with extracellular matrix-like fibrous morphology, suitable mechanical properties, biomineralization capability, and excellent cytocompatibility are desired for bone regeneration. In this work, fibrous and degradable poly(ester urethane)urea (PEUU) scaffolds reinforced with titanium dioxide nanoparticles (nTiO2) were fabricated to possess these properties. To increase the interfacial interaction between PEUU and nTiO2, poly(ester urethane) (PEU) was grafted onto the nTiO2. The scaffolds were fabricated by electrospinning and exhibited fiber diameter of <1µm. SEM and EDX mapping results demonstrated that the PEU modified nTiO2 was homogeneously distributed in the fibers. In contrast, severe agglomeration was found in the scaffolds with unmodified nTiO2. PEU modified nTiO2 significantly increased Young's modulus and tensile stress of the PEUU scaffolds while unmodified nTiO2 significantly decreased Young's modulus and tensile stress. The greatest reinforcement effect was observed for the scaffold with 1:1 ratio of PEUU and PEU modified nTiO2. When incubating in the simulated body fluid over an 8-week period, biomineralization was occurred on the fibers. The scaffolds with PEU modified nTiO2 showed the highest Ca and P deposition than pure PEUU scaffold and PEUU scaffold with unmodified nTiO2. To examine scaffold cytocompatibility, bone marrow-derived mesenchymal stem cells were cultured on the scaffold. The PEUU scaffold with PEU modified nTiO2 demonstrated significantly higher cell proliferation compared to pure PEUU scaffold and PEUU scaffold with unmodified nTiO2. The above results demonstrate that the developed fibrous nanocomposite scaffolds have potential for bone tissue regeneration.