Structural and Interfacial Effects on Drug Release Kinetics of Liquid‑Based Fibrous Catheter

Catheterization is indispensable in the field of modern medicine.However,catheter-related thrombosis and infections almost inevitably occur during the process,and as drugs can only be administered at the end of catheter,auxiliary strategies are required for successful implantation.Considering these intractable limitations,a type of self-adaptive,anti-coagulate liquidbased fibrous catheter has been developed.More importantly,it has positional drug release property that traditional catheters desperately need but couldn’t attain.Although enlightening,the feasibility and performance of the positional drug release have only been demonstrated by fluorescents,the specific drug release kinetics remains unknown for adaptation to application scenarios.Therefore,we systematically investigate the structural and interfacial effects of drug molecules and fibrous matrixes on drug release kinetics in a liquid-based fibrous catheter.Theoretical calculations and experiments demonstrate that oleophilic and hydrophilic molecules release slowly due to a dissolution-diffusion mechanism.Amphipathic molecules,however,will significantly affect the gating performance by affecting the interfacial stability,hence they release quickly with emulsifying the gating liquid.Besides the significant impact of molecular properties and interfacial effects,matrix pore size also has a slight influence that molecules release faster in bigger pores.Through this study,the liquid-based fibrous catheter may step further toward practical applications including chemotherapy,haemodialysis,angiography,etc.to overcome the existing catheter-related limitations.

Design of Porous Membranes by Liquid Gating Technology

CONSPECTUS:Porous membranes are playing paramount roles in the areas of wastewater treatment,chemical analysis,energy storage and conversion,flexible devices,and biomedical engineering.Despite their significance in the above fields,the performances of the porous membrane will be weakened due to the inevitable membrane fouling.Solid surfaces or pores of the membranes are easily contaminated or even clogged due to the absorption of small molecules or the accumulation of fine particles,which lower the flux of fluid transport over time,reduce the separation efficiency,shorten the lifetime of the membranes,and increase the operational costs.In addition,the defects in membranes also hinder their applications to some extent.The above-mentioned limitations all arise from the intrinsic properties of the solid surfaces of the membranes.To solve these challenges,liquid gating technology was proposed,which utilizes the capillary-stabilized functional liquid as a pressure-driven,reversible,and reconfigurable gate to fill and seal the pores on demand.Using liquid gating technology,multiphase transportation in the membrane can be modulated with exceptional antifouling and energy-saving manners due to the defect-free molecular-smooth liquid interface.Moreover,the further responsive interface design accelerated the development of liquid gating membranes and their practical applications to a great extent.In recent years,the concept of the liquid gating membrane has become a reality through developing various porous membranes by the rational selection and design of the two essential parts of the composite membranes:the solid porous matrix and the gating liquid.These membranes expand the basic scientific issues of the traditional membranes from the solid−liquid/gas interface to the solid−liquid−liquid/gas interface and bring more possibilities for the applications of porous membranes.With properties and advantages of antifouling,anticorrosion,enhanced transparency,energy-saving,and stability,these porous membranes have shown various applications in multiphase separation,biomedical catheters,chemical detection,mobile valves,microscale flow control,etc.In this Account,we provide a systematic review of our group’s recent progresses in the design and applications of porous membranes with liquid gating technology.First,we give a comprehensive introduction to the liquid gating technology,followed by further details on how to design porous membranes through liquid gating technology and properties and advantages of the porous membranes.Second,we discuss the applications of these porous membranes in the fields of multiphase separation,biomedical catheters,chemical detection,mobile valves,and microscale flow control.Third,we conclude the Account by describing the current challenges and future directions of the field.

Discontinuous streaming potential via liquid gate

Streaming potential is mainly related to electrokinetic energy conversion,which has been considered to show promising potential for advanced technologies,especially sensing.The inherent property of streaming potential is that the energy conversion process is always a continuous state.However,practical applications include many cases of discontinuous states,such as nonlinear sensing.Here,we report a discontinuous streaming potential electrokinetic energy conversion fluid system.Experiments and theoretical calculations reveal that this system exhibits a discontinuous electrokinetic effect and provides a gating liquid slip in micropores,offering the advantages of gating liquid charge coupling and interfacial drag reduction.Moreover,the system is demonstrated in a wearable fall-down alert application.We expect this liquid gating energy conversion system to open up a platform for the design and application of autonomous health monitoring devices,seismic sea wave warning systems,and beyond.

Alternative photothermal/electrothermal hierarchical membrane for hypersaline water treatment

Over the last decades,the treatment of the large quantities of hypersaline wastewater generated by conventional industries,inland desalination,and fossil-fueled power plants has been an important economic issue and also an inescapable green issue.Here,we developed a versatile interfacial heating membrane with alternating utilization of electricity or solar energy for hypersaline water treat-ment.This hierarchical membrane functions both as a separation membrane and an interface heater,which can quickly(<0.1 s)convert electricity or solar energy into heat to evaporate the outermost layer of hypersaline water.For 10wt% hyper-saline water,the freshwater production rate can reach 16.8kg/m^(2)⋅h by applying a voltage of 10 V and 1.36 kg/m^(2)⋅h under 1-sun illumination.Moreover,it exhibits high electrochemical resistance to corrosion and therefore remains stable tack-ling hypersaline water(>5 wt%),with a high salt rejection rate of 99.99%.This system shows an efficient desalination strategy that can provide fresh water from brines for agriculture and industry,and even for daily life.

Liquid-based materials

Advanced materials are the material basis for social development.Solid materials have the characteristics of stability,durability,and processability,but it is often difficult for them to have a large-scale and rapid dynamic response[1].Liquid materials are usually smooth,defect-free,and self-healing,with dynamic response and high mass transfer efficiency,but they cannot be self-supporting and are unlikely to be fabricated into fixed shapes themselves[2,3].Liquid-based materials are rising for breaking the limitations of conventional materials.They are composed of solids and liquids,which endows them with the characteristics of both solid and liquid materials and unique advantages in fast dynamic response,soft interface,structural plasticity,etc.[2–6].The solid materials offer frameworks and confinements for stabilizing liquid materials.Based on the structure types,the solid framework in the liquid-based materials can be roughly divided into the non-supporting structure,soft supporting structure,and hard supporting structure,although in some conditions,coupled structure types exist(Figure 1).Various liquids with different properties including waterbased liquids,organic liquids,ionic liquids,liquid metals,and other responsive liquids have been widely used[6–10].

Photothermally induced liquid gate with navigation control of the fluid transport

The ability to control multiphase flows is essential for applications such as microvalves,chemical analyses,mi-croreactors,and multiphase separators.Furthermore,more specific controls,including the positional naviga-tion control of fluids under steady-state pressures,will improve the development of these applications.Here,we present a fundamentally new photothermally induced liquid gating system that allows light-controlled con-tactless fluid transport and gas/liquid separations at designated locations,with seconds response times,under constant pressures.Experiments and theoretical calculations demonstrate the stability of our system and its novel regulation mechanism,which is based on a photothermally induced liquid-reconfigurable gate with a change in the surface/interfacial tension and Marangoni flow redistribution of the gating liquid at the illuminated location.This regulation mechanism with positional navigation properties requires neither mechanical parts nor complex accessories and can further enable the miniaturization and integration of various engineering processes.Our ap-plication demonstrations confirm the potential of this system in fields of smart valves,multiphase separations,multiphase microreactors,and beyond.