Incorporating redox-sensitive nanogels into bioabsorbable nanofibrous membrane to acquire ROS-balance capacity for skin regeneration

Facing the high incidence of skin diseases,it is urgent to develop functional materials with high bioactivity for wound healing,where reactive oxygen species(ROS)play an important role in the wound healing process mainly via adjustment of immune response and neovasculation.In this study,we developed a kind of bioabsorbable materials with ROS-mediation capacity for skin disease therapy.Firstly,redox-sensitive poly(N-isopropylacrylamide-acrylic acid)(PNA)nanogels were synthesized by radical emulsion polymerization method using a disulfide molecule as crosslinker.The resulting nanogels were then incorporated into the nanofibrous membrane of poly(L-lactic acid)(PLLA)via airbrushing approach to offer bioabsorbable membrane with redox-sensitive ROS-balance capacity.In vitro biological evaluation indicated that the PNA-contained bioabsorbable membrane improved cell adhesion and proliferation compared to the native PLLA membrane.In vivo study using mouse wound skin model demonstrated that PNA-doped nanofibrous membranes could promote the wound healing process,where the disulfide bonds in them were able to adjust the ROS level in the wound skin for mediation of redox potential to achieve higher wound healing efficacy.

Trace elements and stable isotopic geochemistry of an Early Cambrian chert-phosphorite unit from the lower Yurtus Formation of the Sugetbrak section in the Tarim Basin

A chert-phosphorite unit from the Sugetbrak section in the Tarim Basin was analyzed for rare earth elements(Ce,Eu),redox sensitive proxies,and carbon isotopic compositions(??13C carb and??13C org)in the lower Yurtus Formation of the Early Cambrian period.Redox sensitive element ratios(Th/U,V/Cr,Ni/Co,and V/Sc)were employed to determine the palaeoenvironmental conditions during this period.The ratios indicated that the depositional environment of the chert-phosphorite-black shale unit ranged from suboxic to anoxic.Negative Ce and positive Eu anomalies in the chert-phosphorite assemblages of the studied Yurtus Formation indicated the existence of a redox-stratified ocean,similar to that of South China.Overturn or upward expansion of the deep water-mass probably reached the shallow marine zone after the formation of the Yurtus phosphorites.The characteristics of the negative Ce anomaly may be due to phosphoritic inheritance from the Ce-depleted signature of the overlying water column.Subsequent hydrothermal inputs and reduced detrital supplies of the deep water caused by the upwelling affected certain redox sensitive elements in the sedimentary basin.??13C carb and??13C org negative excursions in the Yurtus chert-phosphorite unit may be related to a transgression phase when episodic basinal upwelling moved12C-and P-rich waters from the pelagic basin floor to the continental shelf.Although carbon isotopic compositions in the Yurtus chert-phosphorite assemblages may have suffered from diagenetic alteration,they can be used to probe diagenetic conditions.Multi-proxy geochemical studies indicated that the??13C carb values of the Yurtus chert-phosphorite assemblages might be considered reflections of a predominantly suboxic environment that was subsequently affected by hydrothermal inputs due to the upwelling.

Self-assembled ternary hybrid nanodrugs for overcoming tumor resistance and metastasis

Traditional chemotherapy exhibits a certain therapeutic effect toward malignant cancer,but easily induce tumor multidrug resistance(MDR),thereby resulting in the progress of tumor recurrence or metastasis.In this work,we deigned ternary hybrid nanodrugs(PEI/DOX@CXB-NPs)to simultaneously combat against tumor MDR and metastasis.In vitro results demonstrate this hybrid nanodrugs could efficiently increase cellular uptake at pH 6.8 by the charge reversal,break lysosomal sequestration by the proton sponge effect and trigger drugs release by intracellular GSH,eventually leading to higher drugs accumulation and cell-killing in drug-sensitive/resistant cells.In vivo evaluation revealed that this nanodrugs could significantly inhibit MDR tumor growth and simultaneously prevent A549 tumor liver/lung metastasis owing to the specifically drugs accumulation.Mechanism studies further verified that hybrid nanodrugs were capable of down-regulating the expression of MDR or metastasis-associated proteins,lead to the enhanced anti-MDR and anti-metastasis effect.As a result,the multiple combination strategy provided an option for effective cancer treatment,which could be potentially extended to other therapeutic agents or further use in clinical test.