Electrolyte Engineering via Fluorinated Siloxane Solvent for Achieving High-Performance Lithium-Metal Batteries.

Advanced solvent is of important significance to develop an excellent electrolyte that simultaneously maintains a high ionic conductivity, wide electrochemical window, and good compatibility with electrodes for high-performance lithium-metal batteries (LMBs). To realize a stable electrode/electrolyte interface and a uniform lithium (Li) deposition process, an optimal fluorinated siloxane (3,3,3-trifluoropropyltrimethoxysilane, TFTMS) is proposed as a cosolvent with 1,2-dimethoxyethane (DME) and highly antioxidative fluoroethylene carbonate (FEC) to formulate a Li-metal compatibility electrolyte. The TFTMS-based electrolyte presents high oxidization stability, high Li+ conductivity, and high Li+ transfer number, contributing to the accelerated reaction kinetics, homogeneous Li deposition behavior, and stable interfacial chemistry. Therefore, high Li stripping/plating reversibility (∼99%) and stable cycling (1400 h) are achieved in the TFTMS-based electrolyte, giving rise to the excellent electrochemical performance of practical Li-metal full cells. Moreover, an industrial 4 Ah NCM811|Gr pouch cell with the TFTMS-based electrolyte is demonstrated to display similar cycling performance with the commercial carbonate electrolyte in 120 cycles at 1 C. This work offers an approach toward high-performance LMBs through rational electrolyte design with fluorinated siloxane solvent.

Truncated peptides from melittin and its analog with high lytic activity at endosomal pH enhance branched polyethylenimine-mediated gene transfection.

BACKGROUND: Melittin is a commonly used cell-penetrating peptide (CPP) for improving branched polyethylenimine (BPEI)-mediated gene transfection. However, its application is limited owing to the cytotoxicity generated by the lytic activity at neutral pH. In the present study, we report two truncated peptides from melittin and florae with improved transfection efficiency. METHODS: Two truncated peptides consisting of 1-20 residues of melittin (MT20) and florae (FL20) were synthesized. Circular dichroism (CD) spectrometry was used to analyze the secondary structures of the peptides. The membrane-lytic activity of the peptides and their potency in enhancing cellular uptake of calcein were evaluated. The peptides and BPEI mixtures were mixed with plasmid DNA to prepare peptide/BPEI/DNA complexes. The physicochemical characters of complexes were measured and the effect of the peptides on BPEI-mediated transfection was determined. RESULTS: CD analysis and structure observation showed that the truncated peptides have α-helical conformation, which was necessary for penetrating activity. The truncated peptides exhibited several advantages than their parent peptides: (i) they showed higher hemolytic potency in acidic pH but lower lytic activity than their parent peptides in neutral pH; (ii) enhanced calcein efficiently release from both early and late endosome; (iii) they did not affect the DNA-binding affinity of BPEI and the physicochemical characteristics of BPEI/DNA complexes. Moreover, the peptides could increase BPEI-mediated transfection efficiency in different cell lines (293FT, B16F10 and CHO-K1) by simply mixing with BPEI, without causing cytotoxicity. CONCLUSIONS: The results obtained in the present study indicate that the truncated peptides with higher endosomal disrupting activity were better enhancers for increasing transfection efficiency.

Comparative assessment of normal and methoxypolyethylene glycol-modified murine red cells on swimming endurance and hippocampal injury in hypoxic mice.

BACKGROUND: Membrane grafting of methoxypolyethylene glycol (mPEG) provides a unique strategy in preventing the immunologic recognition in blood transfusion. mPEG-modified red blood cells (mPEG-RBCs) have acceptable in vitro properties and provide a useful solution to problems with clinical blood matching. The aim of this study was to demonstrate the physiologic normality of mPEG-RBCs in mice. STUDY DESIGN AND METHODS: Mouse RBCs were withdrawn via cardiac bleed and modified with 1.0 mmol per L mPEG with succinimidyl propionate linker. The fluorescein-labeled mPEG-RBCs were then transfused into recipient mice for in vivo survival analysis. At the same time, the exsanguine mouse model was produced, and mice were transfused with mPEG-RBCs. The effects of mPEG-RBC transfusion on the hemoglobin (Hb) level, swimming endurance capacity, and hypoxic-ischemic injury in hippocampal pyramidal cells of exsanguine mice were investigated. RESULTS: mPEG-RBCs showed the same in vivo survival curve and t((1/2)) as those of untreated RBCs. Transfusion of mPEG-RBCs could elevate Hb level of exsanguine mice and improve their swimming endurance capacity, and histologic studies showed that mPEG-RBCs could also restore the hypoxic-ischemic injury of hippocampal pyramidal cells in exsanguine mice, which were similar with control RBCs. That is, mPEG-RBCs functioned in a similar fashion to untreated RBCs in exsanguine mice. Therefore, these results revealed that mPEG-RBCs had normal oxygen-carrying capacity. CONCLUSION: In conclusion, the results confirmed that mPEG-RBCs could perform their in vivo function of carrying O(2) and improve some physiologic indexes of exsanguine mice, and the physiologic normality of mPEG-RBCs provides new findings for clinical use.