Sharp-Line Near-Infrared Emission from Tetrahedron-Occupied Ni2+ in Ca2GeO4.

As far as we are concerned, the phenomenon of Ni2+ luminescence in tetrahedral coordination has not been reported. For the first time, a new NIR phosphor Ca2GeO4:Ni2+ is developed in this work. It is found that the NIR emission from this phosphor is a sharp peak attributed to the unusual Ni2+-occupied GeO4 site in the lattice, instead of the conventional broadband luminescence of Ni2+ in the octahedrally coordinated site. Crystal-field analysis has been applied, and the parameters Dq, B, and Δ are calculated to reveal the relationship between the emission profile and the crystal field strength. The optimal Ni2+ doping concentration is found to be 1%. Ca2GeO4:Ni2+ provides an efficient sharp-line (fwhm = 16 nm) emission centered at 1164 nm which originates from the 1T2 → 3T1 transition with an internal quantum efficiency of 23.1% and a decay lifetime of about 300 µs. This work could provide some new insights to explore novel NIR luminescent materials based on transition-metal elements.

[Preparation and Characterization of Chitosan-Poloxamer-based Antibacterial Hydrogel Containing Silver Nanoparticles].

In order to solve the problem of high cytotoxicity in vitro of nano-silver antibacterial gel,and the problem of large nano-silver particle size and size distribution,this study prepared nano-silver antibacterial gel with better biocompatibility and good antibacterial effect by using physical cross-linking method and using poloxamer as dispersant when prepared nano-silver.In this study,nano-silver was prepared by photo-initiator method and by adding poloxamer as a dispersant,and then UV-visible absorption spectrum test and scanning electron microscopy(SEM)test were carried out using prepared nano-silver mixture and particles after drying respectively.The gel was prepared through adjusting its pH value by using sodium bicarbonate,and then pH value test,SEM test for cross-section of gel,swelling ratio test,viscosity test,inhibition zone test and in vitro cytotoxicity test were carried out.The test results showed that the maximum absorption wavelength of prepared nano-silver,using poloxamer as dispersant and ultra-pure water as solvent,was 414 nm,and the average nano-silver size was about 60 nm.The prepared nano-silver using poloxamer as dispersant had smaller particle diameter and narrower particle size distribution than those using PVP as dispersant.Similarly,the prepared nano-silver using ultra-pure water as solvent also had smaller particle diameter and narrower particle size distribution than those using distilled water as solvent.The pH value of the prepared gel was between 5.8~6.1.The dried gel section had many holes.The water absorption of gel was fine and the viscosity of gel was fit to coat on the gauze.In addition,the prepared gel with nano-silver had greater ability to inhibit Escherichia coli and Staphyloccocus aureus at the concentrations of 24,18 and 12µg/mL.And the biocompatibility of the prepared gel with nano-silver was good when the concentration below 24µg/mL.Based on the above features,the nano-silver antibacterial gel could be used in the treatment of burn or other wounds.

Micromotor-Enabled Active Hydrogen and Tobramycin Delivery for Synergistic Sepsis Therapy.

Sepsis is a highly heterogeneous syndrome normally characterized by bacterial infection and dysregulated systemic inflammatory response that leads to multiple organ failure and death. Single anti-inflammation or anti-infection treatment exhibits limited survival benefit for severe cases. Here a biodegradable tobramycin-loaded magnesium micromotor (Mg-Tob motor) is successfully developed as a potential hydrogen generator and active antibiotic deliverer for synergistic therapy of sepsis. The peritoneal fluid of septic mouse provides an applicable space for Mg-water reaction. Hydrogen generated sustainably and controllably from the motor interface propels the motion to achieve active drug delivery along with attenuating hyperinflammation. The developed Mg-Tob motor demonstrates efficient protection from anti-inflammatory and antibacterial activity both in vitro and in vivo. Importantly, it prevents multiple organ failure and significantly improves the survival rate up to 87.5% in a high-grade sepsis model with no survival, whereas only about half of mice survive with the individual therapies. This micromotor displays the superior therapeutic effect of synergistic hydrogen-chemical therapy against sepsis, thus holding great promise to be an innovative and translational drug delivery system to treat sepsis or other inflammation-related diseases in the near future.

FM-CATH, A Novel Cathelicidin From Fejervarya Multistriata, Shows Therapeutic Potential for Treatment of CLP-Induced Sepsis.

Sepsis is an exacerbated inflammatory reaction induced by severe infection. As important defensive molecules in innate immunity, several AMPs are reported to prevent septic shock. In this study, we characterized a novel cathelicidin, FM-CATH, from the frog skin of F. multistriata. FM-CATH was found to adopt an amphipathic α-helix structural in membrane-mimetic environments and possess favorable antimicrobial effects against bacteria and fungus. In addition, it triggered the agglutination of bacteria. It could also strongly bind to LPS and LTA. Additionally, FM-CATH affected the enzymatic activities of thrombin, plasmin, ß-tryptase, and tPA, leading to coagulation inhibition in vitro and in vivo. Finally, we observed that FM-CATH improved survival rate and inhibited pathological alteration, bacterial count, serum biochemistry, and pro-inflammatory cytokine expression in the cecal ligation and puncture-induced sepsis mice. Taken together, these findings suggest that FM-CATH might be served as a promising agent for the treatment of sepsis.

Brevinin-2GHk, a Peptide Derived from the Skin of Fejervarya limnocharis, Inhibits Zika Virus Infection by Disrupting Viral Integrity.

Several years have passed since the Zika virus (ZIKV) pandemic reoccurred in 2015-2016. However, there is still a lack of proved protective vaccines or effective drugs against ZIKV. The peptide brevinin-2GHk (BR2GK), pertaining to the brevinin-2 family of antimicrobial peptides, has been reported to exhibit only weak antibacterial activity, and its antiviral effects have not been investigated. Thus, we analyzed the effect of BR2GK on ZIKV infection. BR2GK showed significant inhibitory activity in the early and middle stages of ZIKV infection, with negligible cytotoxicity. Furthermore, BR2GK was suggested to bind with ZIKV E protein and disrupt the integrity of the envelope, thus directly inactivating ZIKV. In addition, BR2GK can also penetrate the cell membrane, which may contribute to inhibition of the middle stage of ZIKV infection. BR2GK blocked ZIKV E protein expression with an IC50 of 3.408 ± 0.738 µΜ. In summary, BR2GK was found to be a multi-functional candidate and a potential lead compound for further development of anti-ZIKV drugs.