Smart ionic liquid/water mixture system with dual stimuli-response to temperature and CO_(2)

Stimuli-responsive materials have important applications in chemistry and chemical engineering.Here,we synthesized five different polyetheramine-fatty acids(PEFA)ionic liquids(ILs),possessing the dual stimuli-responsive ability to temperature and CO_(2).These PEFA ILs have reversible lower critical solution temperature(LCST)phase behavior over a wide temperature range of 37-91℃,and reversible heterogeneous-homogeneous phase transition towards the addition and removal of CO_(2).Furthermore,the droplet size of the IL-water mixture system increased from 6.5 to 21.0 nm as the temperature increased from 25 to 56℃,and then recovered to 6.5 nm when the temperature decreased to 25℃.The addition and removal of CO_(2)also reversibly modulated the droplet size of the system.Results from nuclear magnetic resonance(NMR)and Fourier transform infrared(FTIR)spectra further showed that the temperature-dependent conformation of polyether amine chain in the cation dominates the temperature response,while the reversible formation of bicarbonate and fatty acids(FA)from CO_(2)and anion controls the CO_(2)-based reversible phase transition.Molecular simulations revealed a microscopic response mechanism of the IL-water system to temperature and CO_(2),and a synergistic effect between the dual stimuli of temperature and CO_(2).These findings may provide a basis for the rational design and understanding of ILs-based stimuli-responsive materials and nanoreactors.

Recent advances in stimuli-response mechanisms of nano-enabled controlled-release fertilizers and pesticides

Nanotechnology-enabled fertilizers and pesticides,especially those capable of releasing plant nutrients or pesticide active ingredients(AIs)in a controlled manner,can effectively enhance crop nutrition and protection while minimizing the environmental impacts of agricultural activities.Herein,we review the fundamentals and recent advances in nanofertilizers and nanopesticides with controlled-release properties,enabled by nanocarriers responsive to environmental and biological stimuli,including pH change,temperature,light,redox conditions,and the presence of enzymes.For pH-responsive nanocarriers,pH change can induce structural changes or degradation of the nanocarriers or cleave the bonding between nutrients/pesticide AIs and the nanocarriers.Similarly,temperature response typically involves structural changes in nanocarriers,and higher temperatures can accelerate the release by diffusion promoting or bond breaking.Photothermal materials enable responses to infrared light,and photolabile moieties(e.g.,o-nitrobenzyl and azobenzene)are required for achieving ultraviolet light responses.Redox-responsive nanocarriers contain disulfide bonds or ferric iron,whereas enzyme-responsive nanocarriers typically contain the enzyme’s substrate as a building block.For fabricating nanofertilizers,pHresponsive nanocarriers have been well explored,but only a few studies have reported temperature-and enzyme-responsive nanocarriers.In comparison,there have been more reports on nanopesticides,which are responsive to a range of stimuli,including many with dual-or triple-responsiveness.Nano-enabled controlledrelease fertilizers and pesticides show tremendous potential for enhancing the utilization efficiency of nutrients and pesticide AIs.However,to expand their practical applications,future research should focus on optimizing their performance under realistic conditions,lowering costs,and addressing regulatory and public concerns over environmental and safety risks.

Stimuli-Responsive Gene Delivery Nanocarriers for Cancer Therapy

Gene therapy provides a promising approach in treating cancers with high efficacy and selectivity and few adverse effects.Currently,the development of functional vectors with safety and effectiveness is the intense focus for improving the delivery of nucleic acid drugs for gene therapy.For this purpose,stimuli-responsive nanocarriers displayed strong potential in improving the overall efficiencies of gene therapy and reducing adverse effects via effective protection,prolonged blood circulation,specific tumor accumulation,and controlled release profile of nucleic acid drugs.Besides,synergistic therapy could be achieved when combined with other therapeutic regimens.This review summarizes recent advances in various stimuliresponsive nanocarriers for gene delivery.Particularly,the nanocarriers responding to endogenous stimuli including pH,reactive oxygen species,glutathione,and enzyme,etc.,and exogenous stimuli including light,thermo,ultrasound,magnetic field,etc.,are introduced.Finally,the future challenges and prospects of stimuli-responsive gene delivery nanocarriers toward potential clinical translation are well discussed.The major objective of this review is to present the biomedical potential of stimuli-responsive gene delivery nanocarriers for cancer therapy and provide guidance for developing novel nanoplatforms that are clinically applicable.

Smart stimuli-responsive drug delivery systems in spotlight of COVID-19

The world has been dealing with a novel severe acute respiratory syndrome(SARS-CoV-2)since the end of 2019,which threatens the lives of many peopleworldwide.COVID-19 causes respiratory infection with different symptoms,from sneezing and coughing to pneumonia and sometimes gastric symptoms.Researchers worldwide are actively developing novel drug delivery systems(DDSs),such as stimuli-responsive DDSs.The ability of these carriers to respond to external/internal and even multiple stimuli is essential in creating“smart”DDS that can effectively control dosage,sustained release,individual variations,and targeted delivery.To conduct a comprehensive literature survey for this article,the terms“Stimuli-responsive”,“COVID-19”and“Drug delivery”were searched on databases/search engines like“Google Scholar”,“NCBI”,“PubMed”,and“Science Direct”.Many different types of DDSs have been proposed,including those responsive to various exogenous(light,heat,ultrasound andmagnetic field)or endogenous(microenvironmental changes in pH,ROS and enzymes)stimuli.Despite significant progress in DDS research,several challenging issues must be addressed to fill the gaps in the literature.Therefore,this study reviews the drug release mechanisms and applications of endogenous/exogenous stimuli-responsive DDSs while also exploring their potential with respect to COVID-19.

Recent advances in endogenous and exogenous stimuli-responsive nanoplatforms for bacterial infection treatment

As drug-resistant bacterial infections escalate and antimicrobial resources become insufficient,new alternative therapies are critical.The emergence of nano drug delivery system,in addition to giving drugs sustained,targeted or longer half-life characteristics,also plays an important role in improving the therapeutic effect and reducing the toxic side effects of conventional drugs.Despite its potential benefits,the traditional nanomedical drug delivery system has some practical limitations,including incomplete and slow drug release,as well as insufficient accumulation at infection sites.Stimuli responsive nanoplatforms are hence developed to overcome the disadvantages of conventional nanoparticles,which can provide several advantages like:enhancing the pharmacokinetics and biodistribution of antimicrobial drugs,increasing their effective bioavailability,reducing their dosage frequency,and improving their antimicrobial efficacy against biofilm-related infections,while slowing down the development of antimicrobial resistance,which is expected to trigger a medical revolution in the field of human health,thus bringing huge clinical benefits.In this review,we provide an extensive review of the recent progress of endogenous and exogenous stimuli-responsive nanoplatforms in the antibacterial area.Using specific infectious microenvironments(pH,enzymes,reactive oxygen species and toxins),this review systematically presents the design principles of nano delivery systems and the mechanisms by which endogenous stimuli induce changes in the morphology or properties of delivery systems to achieve programmed drug release.Furthermore,exogenous stimuli such as light,heat,and magnetic fields can also control the release of drugs.Last but not least,we discussed the challenges and opportunities for future clinical translation of stimuli-responsive nanoplatforms in bacterial infections.

Stimuli-responsive emulsions:Recent advances and potential applications

Responsive emulsions are the emulsions that can be reversibly switched on-demand between“stable”and“unstable”by environmental stimulus or trigger,which allows a simple and effective adjustment approach to achieve emulsification and demulsification.In recent years,stimuli-responsive emulsions acting as smart soft material are received considerable attention with the advantages of simple manipulation,good reversibility,low cost,easy treatment,and little effect on the system.In this paper,the recent research progress of emulsions that can respond to external stimuli,including pH,light,magnetic field,CO_(2)/N_(2) and dual responsive are reviewed.Also,the potential applications based on responsive emulsion are discussed,such as catalytic reactions,heavy oil recovery,polymer particles synthesis and optical sensor,aiming to summarize the latest achievements and put forward the possible development trends of responsive emulsions.

Recent Advances of D-α-tocopherol Polyethylene Glycol 1000 Succinate Based Stimuli-responsive Nanomedicine for Cancer Treatment

D-a-tocopherol polyethylene glycol 1000 succinate(TPGS)is a pharmaceutical excipient approved by Chinese NMPA and FDA of USA.It's widely applied as a multifunctional drug carrier for nanomedicine.The advantages of TPGS include P-glycoprotein(P-gp)inhibition,penetration promotion,apoptosis induction via mitochondrial-associated apoptotic pathways,multidrug resistant(MDR)reversion,metastasis inhibition and so on.TPGS-based drug delivery systems which are responding to extermal stimulus can combine the inhibitory functions of TPGS towards P-gp with the environmentally responsive controlled release property and thus exerts a synergistic anti-cancer effect,through increased intracellular drug concentration in tumors cells and well-controlled drug release behavior.In this review,TPGS-based nano-sized delivery systems responsive to different stimuli were summarized and discussed,including pH-responsive,redox-responsive and multi-responsive systems in various formulations.The achievements,mechanisms and diffcrent characteristics of TPGS-bascd stimuli-responsive drug-delivery systems in tumor therapy were also outlined.

Stimuli-responsive nanocarriers for therapeutic applications in cancer

Cancer has become a very serious challenge with aging of the human population.Advances in nanotechnology have provided new perspectives in the treatment of cancer.Through the combination of nanotechnology and therapeutics,nanomedicine has been successfully used to treat cancer in recent years.In terms of nanomedicine,nanocarriers play a key role in delivering therapeutic agents,reducing severe side effects,simplifying the administration scheme,and improving therapeutic efficacies.Modulations of the structure and function of nanocarriers for improved therapeutic efficacy in cancer have attracted increasing attention in recent years.Stimuli-responsive nanocarriers penetrate deeply into tissues and respond to external or internal stimuli by releasing the therapeutic agent for cancer therapy.Notably,stimuli-responsive nanocarriers reduce the severe side effects of therapeutic agents,when compared with systemic chemotherapy,and achieve controlled drug release at tumor sites.Therefore,the development of stimuli-responsive nanocarriers plays a crucial role in drug delivery for cancer therapy.This article focuses on the development of nanomaterials with stimuli-responsive properties for use as nanocarriers,in the last few decades.These nanocarriers are more effective at delivering the therapeutic agent under the control of external or internal stimuli.Furthermore,nanocarriers with theranostic features have been designed and fabricated to confirm their great potential in achieving effective treatment of cancer,which will provide us with better choices for cancer therapy.

Smart anticorrosion coating based on stimuli-responsive micro/nanocontainer:a review

Smart coating for corrosion protection of metal materials(steel,magnesium,aluminum and their alloys)has drawn great attention because of their capacity to prevent crack propagation in the protective coating by releasing functional molecules(healing agents or corrosion inhibitors)on demand from delivery vehicle,that is,micro/nanocontainer made up of a shell and core material or a coating layer,in a controllable manner.Herein,we summarize the recent achievements during the last 10 years in the field of the micro/nanocontainer with different types of stimuli-responsive properties,i.e.,pH,electrochemical potential,redox,aggressive corrosive ions,heat,light,magnetic field,and mechanical impact,for smart anticorrosion coating.The state-of-the-art design and fabrication of micro/nanocontainer are emphasized with detailed examples.

Learn to Learn a Foreign Language

This essay is a practical step to Learning Theory.By comparing cognitive learning with non-cognitive learning,the author tries to lay emphasis on creative foreign language learning.

ROS-responsive drug delivery systems for biomedical applications

In the field of biomedicine, stimuli-responsive drug delivery systems(DDSs) have become increasingly popular due to their site-specific release ability in response to a certain physiological stimulus, which may result in both enhanced treatment outcome and reduced side effects. Reactive oxygen species(ROS) are the unavoidable consequence of cell oxidative metabolism. ROS play a crucial part in regulating biological and physiological processes,whereas excessive intracellular ROS usually lead to the oxidation stress which has implications in several typical diseases such as cancer, inflammation and atherosclerosis. Therefore,ROS-responsive DDSs have elicited widespread popularity for their promising applications in a series of biomedical research because the payload is only released in targeted cells or tissues that overproduce ROS. According to the design of ROS-responsive DDSs, the main release mechanisms of therapeutic agents can be ascribed to ROS-induced carrier solubility change, ROS-induced carrier cleavage or ROS-induced prodrug linker cleavage. This review summarized the latest development and novel design of ROS-responsive DDSs and discussed their design concepts and the applications in the biomedical field.

External-stimuli responsive systems for cancer theranostic

The upsurge of novel nanomaterials and nanotechnologies has inspired the researchers who are striving for designing safer and more efficient drug delivery systems for cancer therapy.Stimuli responsive nanomaterial offered an alternative to design controllable drug delivery system on account of its spatiotemporally controllable properties. Additionally, external stimuli(light, magnetic field and ultrasound) could develop into theranostic applications for personalized medicine use because of their unique characteristics. In this review, we give a brief overview about the significant progresses and challenges of certain externalstimuli responsive systems that have been extensively investigated in drug delivery and theranostics within the last few years.

Touch-Responsive Hydrogel for Biomimetic Flytrap-Like Soft Actuator

Stimuli-responsive hydrogel is regarded as one of the most promising smart soft materials for the next-generation advanced technologies and intelligence robots,but the limited variety of stimulus has become a non-negligible issue restricting its further development.Herein,we develop a new stimulus of“touch”(i.e.,spatial contact with foreign object)for smart materials and propose a flytrap-inspired touch-responsive polymeric hydrogel based on supersaturated salt solution,exhibiting multiple responsive behaviors in crystallization,heat releasing,and electric signal under touch stimulation.Furthermore,utilizing flytrap-like cascade response strategy,a soft actuator with touch-responsive actuation is fabricated by employing the touch-responsive hydrogel and the thermo-responsive hydrogel.This investigation provides a facile and versatile strategy to design touch-responsive smart materials,enabling a profound potential application in intelligence areas.

Design, preparation and pharmacodynamics of ICG-Fe(Ⅲ) based HCPT nanocrystals against cancer

The use of nanocrystal technology to manufacture drug delivery systems intended to enhance therapeutic efficacy has attracted the attention of the pharmaceutical industry.However,the clinical application of nanocrystal drugs for injection is restricted by Ostwald ripening and the large-scale use of stabilizers such as polysorbate and lecithin,which have potential toxicity risks including hemolysis and allergies.Here,we designed an amorphous nanocrystal drug complex(IHNC),which is stabilizer-free and composed of indocyanine green(ICG)framework loading with a chemotherapeutic agent of 10-hydroxycamptothecin(HCPT).Considering the possibility of industrial manufacturing,IHNC was simply prepared with the assistance of ferric ion(III)via supramolecular assembly strategy.The theoretical result of Materials Studio simulation indicated that the prepared ICG-Fe(III)framework showed a stable spherical structure with the appropriate cavity for encapsulating the two drugs of HCPT and ICG with equal mass ratio.The IHNC was stable at physiological pH,with excellent PTT/PDT efficacy,and in vivo probing characteristics.The nanoscale size and reductive stimuli-responsiveness can be conducive to drug accumulation into the tumor site and rapid unloading of cargo.Moreover,such combination therapy showed synergistic photo/chemotherapy effect against 4T1 breast cancer and its tumor inhibition rate even up to 79.4%.These findings demonstrated that the nanocrystal drug delivery strategy could avoid the use of stabilizers and provide a new strategy for drug delivery for combination therapy.

Remotely Activated Nanoparticles for Anticancer Therapy

Cancer has nowadays become one of the leading causes of death worldwide.Conventional anticancer approaches are associated with different limitations.Therefore,innovative methodologies are being investigated,and several researchers propose the use of remotely activated nanoparticles to trigger cancer cell death.The idea is to conjugate two different components,i.e.,an external physical input and nanoparticles.Both are given in a harmless dose that once combined together act synergistically to therapeutically treat the cell or tissue of interest,thus also limiting the negative outcomes for the surrounding tissues.Tuning both the properties of the nanomaterial and the involved triggering stimulus,it is possible furthermore to achieve not only a therapeutic effect,but also a powerful platform for imaging at the same time,obtaining a nano-theranostic application.In the present review,we highlight the role of nanoparticles as therapeutic or theranostic tools,thus excluding the cases where a molecular drug is activated.We thus present many examples where the highly cytotoxic power only derives from the active interaction between different physical inputs and nanoparticles.We perform a special focus on mechanical waves responding nanoparticles,in which remotely activated nanoparticles directly become therapeutic agents without the need of the administration of chemotherapeutics or sonosensitizing drugs.

Recent studies of Pickering emulsion system in petroleum treatment:The role of particles

Pickering emulsions stabilized by solid particles have gained much attention,which afford high stability,low toxicity,controllable rheological properties and stimuli-responsive behavior compared to the traditional emulsions emulsified by surfactants.Those particles,as the core parts of the emulsion systems,play an important role in the fabrication and application of Pickering emulsion systems,making them attractive in petroleum fields.In this review,the influence of various particles on the stability and properties of Pickering emulsion systems as well as recent researches associated with the stimuliresponsibility of Pickering emulsion systems are introduced.Specifically,the design of functional particles and Pickering emulsion systems with super stabilities and controllable rheological properties are listed.Furthermore,some petroleum application of Pickering emulsion systems for enhanced oil recovery and spilled oil collection as well as the application as soft templates to fabricate oil-absorbing material and as three-phase microreactors that most likely for petroleum application are discussed,and the issues hindering the actual application of Pickering emulsion systems are also evaluated.This review charts a way for Pickering emulsion studies that could lead to a valid petroleum application through design of the particles served as the enhancers of Pickering emulsion stability for purpose of tailoring chemical flooding.

Current multifunctional albumin-based nanoplatforms for cancer multi-mode therapy

Albumin has been widely applied for rational design of drug delivery complexes as natural carriers in cancer therapy due to its distinct advantages of biocompatibility,abundance,low toxicity and versatile property.Hence,various types of multifunctional albumin-based nanoplatforms(MAlb-NPs)that adopt multiple imaging and therapeutic techniques have been developed for cancer diagnosis and treatment.Stimuli-responsive release,including reduction-sensitive,p H-responsive,concentration-dependent and photodynamic-triggered,is important to achieve low-toxicity cancer therapy.Several types of imaging techniques can synergistically improve the effectiveness of cancer therapy.Therefore,combinational theranostic is considered to be a prospective strategy to improve treatment efficiency,minimize side effects and reduce drug resistance,which has received tremendous attentions in recent years.In this review,we highlight several stimuli-responsive albumin nanoplatforms for combinational theranostic.

Dual responsive block copolymer coated hollow mesoporous silica nanoparticles for glucose-mediated transcutaneous drug delivery

A self-regulated anti-diabetic drug release device mimicking pancreatic cells is highly desirable for the therapy of diabetes. Herein, a glucose-mediated dual-responsive drug delivery system, which combines pH-and H_(2)O_(2)-responsive block copolymer grafted hollow mesoporous silica nanoparticles(HMSNs)with microneedle(MN) array patch, has been developed to achieve self-regulated administration.The poly[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate]-b-poly[2-(dimethylamino)ethyl methacrylate](PPBEM-b-PDM) polymer serves as gate keeper to prevent drug release from the cavity of HMSNs at normoglycemic level. In contrast, the drug release rate is significantly enhanced upon H_(2)O_(2)and pH stimuli due to the chemical change of H_(2)O_(2)sensitive PPBEM block and acid responsive PDM block. Therefore, incorporation of anti-diabetic drug and glucose oxidase(GOx, which can oxidize glucose to gluconic acid and in-situ produce H_(2)O_(2)) into stimulus polymer coated HMSNs results in a glucose-mediated MN device after depositing the drug-loaded nanoparticles into MN array patch. Both in vitro and in vivo results show this MN device presents a glucose mediated self-regulated drug release characteristic, which possesses a rapid drug release at hyperglycemic level but retarded drug release at normoglycemic level. The result indicates that the fabricated smart drug delivery system is a good candidate for the therapy of diabetes.

Nanoscale Metal-Organic Frameworks:Stimulus-Response and Applications

Metal-organic frameworks(MOFs),a crystalline porous material with a periodic net-work structure formed by the self-assembly of transition metal ions and organic ligands,have been widely applied in various fields due to their rich composition and structural diversity.Among vari-ous types of MOFs,stimuli-responsive MOFs have gained increasing attention in recent years,because of their broad application in the field of physics,biology,and chemistry.In this review,we analyzed and classified the mechanism of stimulus-response MOFs(pH response,glucose response,GSH response,light response,temperature response)and their applications in drug delivery,adsorption and luminescence functions,magnetization and catalysis functions,probe and sensor.

Reduction and pH-responsive performance of nitroxide radical-containing copolymers probed by EPR spectroscopy Dedicated to Professor Chaohui Ye on the occasion of his 80th birthday

Although stimuli-responsive polymers have appeared as promising materials for drug administration,the effectiveness of these materials on various bioinspired stimuli is still open for dispute.In this work,the stimuli-responsive behaviors of radical-containing nonamphiphilic copolymers were investigated using electron paramagnetic resonance(EPR)spectroscopy while altering the pH and reductant concentration.The concentration of radicals in the aqueous solution had a considerable impact on self-assembly.The nitroxide radicals(hydrophobic)were converted to hydroxylamine(hydrophilic)when ascorbic acid(Asc)was added as a reductant,and the assemblies were switched to dissolution with a rate control behavior.The behavior of morphological change was observed in the acidic pH due to the disproportionation reaction of nitroxide radicals forming cationic species.The acquired results give new insights into the colloidal nanoparticles of nonamphiphilic copolymers and encourage the development of comparable responsive nanoparticles with intriguing drug delivery applications.