Constructing Lanthanide-Organic Complexes for X-ray Scintillation and Imaging.

The photoluminescent properties of lanthanide complexes have been thoroughly investigated; however, there have been much fewer studies showcasing their potential use in ionizing radiation detection. In this work, we delve into the photo- and radio-induced luminescence of a series of lanthanide-bearing organic-inorganic hybrids and their potential as a platform for X-ray scintillation and imaging. The judicious synergy between lanthanide cations and 2,6-di(1H-pyrazol-1-yl)isonicotinate (bppCOO-) ligands affords six new materials with three distinct structures. Notably, Eu-bppCOO-1 and Tb-bppCOO-2 display sharp fingerprint X-ray-excited luminescence (XEL), the intensities of which can be linearly correlated with the X-ray dose rates over a broad dynamic range (0.007-4.55 mGy s-1). Moreover, the X-ray sensing efficacies of Eu-bppCOO-1 and Tb-bppCOO-2 were evaluated, showing that Tb-bppCOO-2 features a lower detection limit of 4.06 µGy s-1 compared to 14.55 µGy s-1 of Eu-bppCOO-1. Given the higher X-ray sensitivity and excellent radiation stability of Tb-bppCOO-2, we fabricated a flexible scintillator film for X-ray imaging by embedding finely ground Tb-bppCOO-2 in the polydimethylsiloxane (PDMS) polymer. The resulting scintillator film can be utilized for high-resolution X-ray imaging with a spatial resolution of approximately 7 lp mm-1.

A ratiometric radio-photoluminescence dosimeter based on a radical excimer for X-ray detection.

A novel radio-photoluminescence material featuring fluorochromic responses toward UV or X-ray irradiation has been obtained. Such a unique monomer- to excimer-based luminescence transition allows for dosimetry of ionizing radiation in a ratiometric manner. Rather than quenching the luminescence, the radiation-induced radical species of Th-105 boost the excimer emission, rendering it as a rare material possessing radical-excimers.

Micron-sized SiO x /N-doped carbon composite spheres fabricated with biomass chitosan for high-performance lithium-ion battery anodes.

To achieve superior lithium storage performance, SiO x is usually designed into nanostructured SiO x /C composites by complex or expensive methods. Here, micron-sized interconnected SiO x /N-doped carbon (NC) microspheres composed of evenly dispersed SiO x nano-domains and NC have been fabricated by a scalable microemulsion method and following pyrolysis, using vinyltriethoxysilane and chitosan as precursors. The unique structure of the micron-sized SiO x /NC spheres leads to enhanced structural integrity and enables stable long-term cycling (800 cycles at 2 A g-1). Benefiting from the enhanced electron/Li+ diffusion kinetics originated from the unique structure and N-doping, SiO x /NC-2 presents considerable capacitive-controlled Li storage capacity, which leads to outstanding rate capability. Consequently, the assembled SiO x /NC-2//LiFePO4 full cell exhibits superior rate capability (106 mA h g-1 at 4C) and stable long-term cycling at 2C (102 mA h g-1 after 350 cycles). This work opens a new door for the application of chitosan in building micron-sized high-performance SiO x /C anode materials, and to some extent facilitates the recycling of waste seafood shells.

The long-term behaviors and differences in bone reconstruction of three polymer-based scaffolds with different degradability.

Scaffolds composed of polymers and nano-hydroxyapatite (n-HA) have received extensive attention in bone reconstructive repair; however there is a lack of in-depth and long-term comparative study on the effect of scaffold degradability on bone reconstruction. In this study, the osteogenic behaviors of three polymeric composite scaffolds based on fast degradable poly(lactic-co-glycolic acid) (PLGA), slowly degradable polycaprolactone (PCL) and non-degradable polyamide 66 (PA66) were investigated and compared via implanting the scaffolds into rabbit femoral defects for 1, 3, 6 and 12 months. The in vivo results demonstrated that although the n-HA/PLGA scaffold could obtain higher new bone volume at 3 months, its fast degradation caused the loss of scaffold structural integrity and led to reduction of bone volume after 3 months. The n-HA/PCL scaffold displayed slow degradation mainly after 6 months (∼20% degradation) and the n-HA/PA66 scaffold showed no degradation during the entire 12 months; these two scaffolds could maintain their structural integrity and exhibited a constant increase in bone volume with the implantation time, and even achieved higher bone volume than the n-HA/PLGA scaffold at 12 months. The year-long in vivo research revealed the following important aspects: (1) bone reconstruction is strongly related to scaffold degradability, and the scaffold structural integrity should be maintained at least for one year before complete degradation in vivo; (2) the in vivo experiment of a bone scaffold must take more time than the conventional 3 or 6 months, which is normally neglected. The study suggests a principle for future design and application of bone scaffolds that must have a relatively stable osteogenic space and scaffold interface, or have a scaffold degradation speed slower than the time of bone reconstruction completion.

2D ultrathin carbon nanosheets with rich N/O content constructed by stripping bulk chitin for high-performance sodium ion batteries.

Two-dimensional (2D) nanomaterials hold considerable potential in reforming the energy storage performance, and the efficient production of high-performance 2D energy storage materials through facile and sustainable approaches is highly desirable. Herein, for the first time, large-area and ultrathin carbon nanosheets doped with N/O were constructed by stripping bulk chitin via a "top-down" method. On the basis of the specific layered structure composed of nanofibers, chitin samples after removing the protein and CaCO3 could be efficiently exfoliated into nanosheets (CNs) via the hydrothermal method, which were then carbonized into N/O co-doped porous carbon nanosheets (CCNs). The CCNs with a thickness of about 3.8 nm retained the original nanosheet structure consisting of nanofibers, leading to a 2D structure with hierarchical porosities. When used as anode materials for sodium-ion batteries, the 2D porous nanostructures and abundant N/O doping of CCNs-600 (carbonized at 600 °C) enable a high reversible capacity of 360 mA h g-1 at 50 mA g-1, a good rate capability of 102 mA h g-1 at 10 A g-1, and an excellent cycling stability of 140 mA h g-1 after 10 000 cycles at a high density of 5 A g-1. Full cells consisting of a CCN anode and a Na3V2(PO4)3/C cathode exhibited favorable rate performance and cycling stability, showing potential application prospects in highly efficient energy storage systems.

Modification of 3D printed PCL scaffolds by PVAc and HA to enhance cytocompatibility and osteogenesis.

In the study, a specific material system that contains poly-(ε-caprolactone) (PCL), polyvinyl acetate (PVAc) and hydroxyapatite (HA) was used to fabricate porous scaffolds employing a 3D printing technique for bone regeneration. Four groups of 3D printing scaffolds were fabricated: PCL, PCL/PVAc, PCL/HA and PCL/PVAc/HA for comparision. The morphologies, mechanical properties and biological characteristics of these scaffolds were analyzed using SEM, a material testing machine, in vitro cell culture and in vivo animal experiments. The results showed that these 3D printed scaffolds possessed porous channel structures with a hole size of 375-475 µm and porosity of 74.1-76.1%. The compressive moduli of the scaffolds increased with the addition of HA and decreased with the addition of PVAc. The PCL/PVAc/HA scaffold exhibited higher cell proliferation and bone formation rates than other groups (p < 0.001), which could be attributed to the synergistic effect of PAVc and HA components. Two types of new bone formation patterns in the scaffold were found in this study: one is the new bone formed directly on the grid matrix, and the other is the new bone initially formed in the center of the scaffold channel and then remolded to concentric circles. The osteogenesis pattern of the latter is analogous to the osteon structure of a cortical bone. The 3D printed scaffold based on PCL/PVAc/HA tri-component system is a promising prospect for future individualized bone repair applications.

Three-Dimensional Printing of Drug-Loaded Scaffolds for Antibacterial and Analgesic Applications.

Pneumatic extrusion-based three-dimensional (3D) printing can be used to fabricate custom-made scaffolds to restore irregular bone defects. During the 3D printing process, therapeutic agents can be added to the scaffolds. This study aimed to develop a polycaprolactone (PCL) scaffold loaded with Ag3PO4 to prevent infections and lidocaine for pain relief by one-step 3D printing. We hypothesized that the drug release could be controlled by varying the filament diameter of the 3D printed scaffolds. To this end, PCL slurry mixed with different amounts of silver phosphate and lidocaine was printed via differently sized nozzles. The obtained cylindric scaffolds displayed a porous interconnected microstructure with high fidelity. The Ag3PO4 and lidocaine were distributed homogeneously. The lidocaine release could be controlled by adjusting the filament diameter while the silver release is correlated with the Ag3PO4 loading amount. The released medium from silver-loaded scaffolds exhibited an obvious inhibition zone against Staphylococcus aureus and Escherichia coli upon loading with 1% Ag3PO4 for up to 6 days and with 3% Ag3PO4 for at least 7 days. Cytotoxicity of all scaffolds was screened by cell assay. In conclusion, the pneumatic extrusion-based 3D printing provides a practical technique to fabricate drug-loaded scaffolds. The Ag3PO4 and lidocaine loaded PCL scaffolds showed the potential for infection prevention and pain relief.

Elastomeric Polyurethane Foams Incorporated with Nanosized Hydroxyapatite Fillers for Plastic Reconstruction.

Plastic surgeons have long searched for the ideal materials to use in craniomaxillofacial reconstruction. The aim of this study was to obtain a novel porous elastomer based on designed aliphatic polyurethane (PU) and nanosized hydroxyapatite (n-HA) fillers for plastic reconstruction. The physicochemical properties of the prepared composite elastomer were characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), thermal analysis, mechanical tests, and X-ray photoelectron spectroscopy (XPS). The results assessed by the dynamic mechanical analysis (DMA) demonstrated that the n-HA/PU compounded foams had a good elasticity, flexibility, and supporting strength. The homogenous dispersion of the n-HA fillers could be observed throughout the cross-linked PU matrix. The porous elastomer also showed a uniform pore structure and a resilience to hold against general press and tensile stress. In addition, the elastomeric foams showed no evidence of cytotoxicity and exhibited the ability to enhance cell proliferation and attachment when evaluated using rat-bone-marrow-derived mesenchymal stem cells (BMSCs). The animal experiments indicated that the porous elastomers could form a good integration with bone tissue. The presence of n-HA fillers promoted cell infiltration and tissue regeneration. The elastomeric and bioactive n-HA/PU composite foam could be a good candidate for future plastic reconstruction.

Study on Chemical Constituents in Polygoni Cuspidati Folium and its Preparation by UPLC-ESI-Q-TOF-MS/MS.

A rapid and credible analytical method was developed using online UPLC-ESI-Q-TOF-MS/MS to identify chemical constituents in Polygoni cuspidati folium and its preparation. By accurate mass measurements within 6.5 ppm error for [M-H]- ion in routine analysis, 26 chemical constituents, including tannin, derivatives of phenylpropionic acid, stilbene, flavonoid, anthraquinone, torachryson and its derivatives, were identified or tentatively characterized. Among them, five constituents (compounds 19-23) were firstly reported in Polygoni cuspidati folium, other 17 constituents were coexisting in both Polygoni cuspidati folium and its preparation. Fragmentation behaviors of different categories of constituents were also investigated to confirm the results. This established UPLC-ESI-Q-TOF-MS/MS method, with reliance and efficiency for the identification the major constituents, would be the basis for quality control of Polygoni cuspidati folium and its preparation.