No abstract

Over the past decade, high strength hydrogels have been intensively investigated. However, developing high strength biofunctional hydrogels for eliciting bone regeneration has been rarely reported. In this work, a mineralized high strength and tough hydrogel is synthesized by one‐step copolymerization of acrylonitrile, 1‐vinylimidazole, and polyethylene glycol diacrylate, followed by in situ precipitation mineralization. It is demonstrated that the CNCN dipole–dipole pairings combined with the interaction of CaP nanocrystals with polymer chains contribute to tremendous increase of tensile/compressive strength, modulus, and fracture energy up to 6.1 MPa, 11.5 MPa, 6.47 MPa, and 7935 J m−2, respectively. The biomineralization is shown to facilitate the attachment and proliferation of C2C12 cells in vitro. This biomineralized hydrogel scaffold is implanted into an 8 mm diameter critical‐size of calvarial defect of rats to evaluate the bone regeneration. 12 week postsurgery results reveal that the mineralized hydrogel exhibits the highest bone volume and density within the defect as measured by computed tomography and histology. This mineralized high strength and tough hydrogel offers a broad range of possibilities to be developed as biofunctional scaffold to promote the reconstruction and regeneration of not only bone, but also load‐bearing connective tissue.

No abstract

A fast and reliable analytical method is reported for the quantitative determination of dissolved elemental sulfur in non-aqueous electrolytes for Li-S batteries. By using high performance liquid chromatography with a UV detector, the solubility of S in 12 different pure solvents and in 22 different electrolytes was determined. It was found that the solubility of elemental sulfur is dependent on the Lewis basicity, the polarity of solvents and the salt concentration in the electrolytes. In addition, the S content in the electrolyte recovered from a discharged Li-S battery was successfully determined by the proposed HPLC/UV method. Thus, the feasibility of the method to the online analysis for a Li-S battery is demonstrated. Interestingly, the S was found super-saturated in the electrolyte recovered from a discharged Li-S cell.

In this study, a d-glucosamine derivative with an isonitrile group (CN5DG) was synthesized and it was chosen to coordinate with Tc for preparingTc-CN5DG. Tc-CN5DG could be readily obtained with high radiochemical purity (>95%) and had great in vitro stability and metabolic stability in urine. The radiotracer demonstrated a positive response to the administration of glucose and insulin in S180 and A549 tumor cells in vitro, suggesting the mechanism of Tc-CN5DG into tumor cells was related to glucose transporters. Biodistribution studies in mice bearing A549 xenografts showedTc-CN5DG had a high tumor uptake and high tumor-to-background ratios. SPECT/CT images further supported its ability for tumor imaging. As a cheap, conveniently made and widely available probe, Tc-CN5DG would become a potential "working horse" and be a breakthrough inTc-labeled radiopharmaceuticals for tumor detection.

No abstract

Fibroblast activation protein (FAP) is overexpressed in cancer-associated fibroblasts (CAFs) in a majority of human epithelial cancers. With low expression in normal organs, FAP has become a promising molecular target for tumor theranostics. To develop a lower cost and more widely available alternative to positron emission tomography (PET), two isocyanide-containing FAP inhibitors (CN-C5-FAPI and CN-PEG4-FAPI) were synthesized and radiolabeled with 99mTc to obtain [99mTc]­[Tc-(CN-C5-FAPI)6]+ and [99mTc]­[Tc-(CN-PEG4-FAPI)6]+ in high yields (>95%). They showed good stability in saline and mouse serum. The partition coefficient (log P) values of [99mTc]­[Tc-(CN-C5-FAPI)6]+ and [99mTc][Tc-(CN-PEG4-FAPI)6]+ were −0.86 ± 0.03 and −2.38 ± 0.07, respectively, indicating that they were good hydrophilic complexes. The low nanomolar IC50 values of CN-C5-FAPI and CN-PEG4-FAPI indicated that they had specificity to FAP. In vitro cellular uptake and blocking experiments implied a FAP-targeted uptake mechanism. The nanomolar K d values from the saturation binding assay indicated that they had significantly high target affinity to FAP. The biodistribution and blocking study in BALB/c nude mice bearing U87MG tumors showed that both exhibited specific tumor uptake. [99mTc]­[Tc-(CN-PEG4-FAPI)6]+ showed a higher tumor uptake and a higher tumor/nontarget ratio than [99mTc]­[Tc-(CN-C5-FAPI)6]+. The results of micro-single-photon emission computed tomography (SPECT) imaging studies of [99mTc]­[Tc-(CN-C5-FAPI)6]+ and [99mTc][Tc-(CN-PEG4-FAPI)6]+ were in accordance with the biodistribution results, suggesting that [99mTc]­[Tc-(CN-PEG4-FAPI)6]+ is a promising tumor imaging agent for targeting FAP.

Ab initio calculations are performed to investigate the host-guest interactions and multiple occupancies of some sulfur- (HS, CS) and nitrogen-containing (N, NO, and NH) molecules in dodecahedral, tetrakaidecahedral, and hexakaidecahedral water cages in this work. Five functionals in the framework of density functional theory are compared, and the M06-2X method appears to be the best to predict the binding energies as well as the geometries. Results show that N and NO molecules are more stable in the 56 cage, while NH and HS prefer to stabilize in the 56 cage. This suggests that the sI hydrates of NH and HS exhibit higher stability than the sII structures and that sII NO hydrate is more stable than sI NO hydrate. N is found to be more stable in type II structure with single occupancy and to form type I hydrate with multiple occupancy, which is consistent with the experimental observations. As to the guest molecule CS, it may undergo severe structural deformation in the 5 and 56 cage. For multiple occupancies, the 5, 56, and 56 water cages can trap up to two N molecules, and the 56 water cage can accommodate two HS molecules. This work is expected to provide new insight into the formation mechanism of clathrate hydrates for atmospherically important molecules.