A mild phenoxysilyl linker for self-immolative release of antibody-drug conjugates

Self-immolative linkers have been widely used to construct prodrugs to improve their efficacy and safety.In this study,we report the use of phenoxysilyl linker as a self-immolative unit to prepare antibody-drug conjugates(ADCs).Phenoxysily based ADC Ate-PPS-CA4 was prepared and its release was systematically investigated by mass spectrometry.Biological evaluation showed that Ate-PPS-CA4 displayed the ability to target delivery and self-immolative release the active payload CA4 on PD-L1 positive cells MDA-MB-231.As the same with its payload CA4,it could arrest the cell cycle to the G2/M phase and induced changes in cell morphology at the dose of its IC_(50).The development of this linker with novel drug release mechanisms will expand the methodology to construct ADCs,especially for non-internalizing ADCs by extracellular cleavage.

Formulation of lyotropic liquid crystal emulsion based on natural sucrose ester and its tribological behavior as novel lubricant

The tribological behavior of oil-in-water emulsions formulated with natural lyotropic liquid crystal(LLC)emulsifiers based on natural sucrose ester was studied for the first time.Polarized optical microscopy,synchrotron radiation small-angle X-ray scattering,wide-angle X-ray scattering,and synchrotron radiation infrared microspectroscopy demonstrated that LLC emulsifiers were tightly ordered at the oil–water interface with a distinct nematic texture.The viscosity of emulsion was observed to change over time.Moreover,the zeta potential and laser particle size distribution verified the emulsion’s satisfactory stability.The frictional shearing test proved that the coefficient of friction of the emulsion versus pure oil decreased by 34.2%.The coefficient of friction of the emulsion with liquid crystal decreased 10.1%versus that without liquid crystal.Although liquid crystal emulsion did not exhibit outstanding anti-wear performance compared with pure oil,its wear volume was 29.4%less than the emulsion without liquid crystal.X-ray photoelectron spectroscopy and scanning electron microscope–energy dispersive X-ray spectroscopy(SEM–EDS)proved that the tribo-film of the emulsion with liquid crystal was formed synergistically by the liquid crystal phase with the base oil.The formulation affecting the lubricant quality was further studied by orthogonal experiments.The resulting Stribeck curve behavior suggested that proper composition with a slightly higher viscosity can better reduce friction in both boundary lubrication and mixed lubrication regimes.The lubrication mechanism indicated that the periodically ordered liquid crystal was transported to the sliding asperity in the form of emulsion droplets,which bored the pressure and released the oil to form a tribo-film.This LLC emulsion is environmentally friendly and potentially non-irritant to the skin.Thus,it has promising application prospects as novel water-based and biological lubricants.

Tribological behavior of nanocarbon materials with different dimensions in aqueous systems

Due to the widespread use of nanocarbon materials(NCMs),more researchers are studying their tribological performances.In this work,the tribological behaviors of the following five types of NCMs with different geometric shapes were evaluated in a novel oil‐in‐water system:spherical fullerenes(C60,0D),tubular multi‐walled carbon nanotubes(MWCNT,1D),sheet graphene oxide(GO,2D),sheet graphene oxide derivative(Oct‐O‐GO,2D),and lamellar graphite(G,3D).Among these,GO with two types of oxidation degrees,i.e.,GO(1),GO(2),and Oct‐O‐GO(1)were synthesized and characterized using Fourier‐transform infrared spectroscopy,Raman spectroscopy,x‐ray diffraction,thermogravimetric analysis,scanning electron microscopy,and contact angle measurements.The load‐carrying capacity of the NCM emulsions were evaluated using a four‐ball test machine,and the lubrication performances were investigated using a high‐frequency reciprocating friction and wear tester with a sliding distance of 1,800 mm under different loads(50 N and 100 N)at 0.5 Hz.The results revealed that the Oct‐O‐GO(1)emulsion exhibited the best load‐carrying capacity,and the best friction‐reducing and anti‐wear properties compared to other emulsions.Moreover,the anti‐wear advantage was more prominent under high load conditions,whereas the other emulsions exhibited a certain degree of abrasive or adhesive wear.The lubrication mechanism was determined through the analysis of worn surfaces using scanning electron microscopy/energy‐dispersive x‐ray spectroscopy,micro‐Raman spectroscopy,and x‐ray photoelectron spectroscopy.The results revealed that during frictional sliding,the ingredients in the emulsion can absorb and react with the freshly exposed metal surface to form surface‐active films to protect the surfaces from abrasion.Moreover,it was found that the higher the amount of ingredients that contain alkyl and O‐H/C=O,the better was the lubrication performance in addition to an increase in the carbon residue in the tribofilm generated on the meal surface.

Water lubrication of graphene oxide-based materials

Water is as an economic,eco-friendly,and efficient lubricant that has gained widespread attention for manufacturing.Using graphene oxide(GO)-based materials can improve the lubricant efficacy of water lubrication due to their outstanding mechanical properties,water dispersibility,and broad application scenarios.In this review,we offer a brief introduction about the background of water lubrication and GO.Subsequently,the synthesis,structure,and lubrication theory of GO are analyzed.Particular attention is focused on the relationship between pH,concentration,and lubrication efficacy when discussing the tribology behaviors of pristine GO.By compounding or reacting GO with various modifiers,amounts of GO-composites are synthesized and applied as lubricant additives or into frictional pairs for different usage scenarios.These various strategies of GO-composite generate interesting effects on the tribology behaviors.Several application cases of GO-based materials are described in water lubrication,including metal processing and bio-lubrication.The advantages and drawbacks of GO-composites are then discussed.The development of GO-based materials for water lubrication is described including some challenges.

Synthesis of Pillar[n]arene[5−n]quinines via Partial Oxidation of Pillar[5]arene

An improved partial oxidation of 1,4-dimethoxypillar[5]arene(DMP[5])was described,through which selected pillar[n]arene[5−n]quinones,such as pillar[4]arene[1]quinone,pillar[3]arene[2]quinone,pillar[2]arene[3]quinone and pillar[1]arene[4]quinone,were synthesized by manipulating the ratio of oxidative reagent(NH4)2[Ce(NO3)6]to DMP[5].

Stable graphene oxide-based lyotropic liquid crystals for interfacial lubrication

Lyotropic liquid crystals have lubricating properties due to their ordered assembly and fluidity,whose mesogens are often characterized by amphiphilic properties.Despite the attention that graphene oxide(GO)has been studied as a novel amphiphilic lyotropic mesogen this decade,and GO applied as a lubrication additive has been demonstrated in both oil and water-based systems,little research reveals the interfacial lubrication of GO liquid crystals yet.This work reports that GO aqueous dispersion can form lyotropic liquid crystals above a specific critical concentration of 5.00 mg/mL,providing a form of stable water-based lubricant,which can keep stable for several months and can reduce friction by 37.3%and wear by 25.24%.The liquid crystal phase was verified by polarizing microscope and synchrotron radiation small-angle X-ray scattering,and its rheological properties and viscoelasticity were studied by interfacial rheometer.The formation of lyotropic liquid crystals can enhance the stability of GO aqueous dispersions at high density,simultaneously ensuring friction decrease and anti-wear effect.It is attributed to the stable nematic network by the ordered GO sheets.The ordered assembly structure bears vertical shear force,therefore,reducing the wear.It is also assumed that the wide lateral size of graphene oxide promotes the nematic phase thus smoothes the graphene oxide film composed spontaneously under the coincidence of lamellar liquid crystal and 2D layered material.Through this work,the interlayer lubrication of GO was optimized,and the problem of GO dispersion sedimentation was solved by self-assembly.The range of interfacial lubrication of GO aqueous dispersion has been expanded and the synergistic effect is conducive to the environmentally friendly lubricants.