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A judicious strategy was utilized to envision the substantial regio-positional effects of substituents on the photophysical properties of the 2H-chromen-2-one-3-benzothiazole scaffold-based push-pull framework, named 6-X-CUMs. Among them, 6-NEt2-CUM reveals prominent excited-state intramolecular charge transfer with a large change of dipole moment (Δμ ∼ 18.23 D), hence displaying remarkable emission solvatochromism from the green (536 nm in cyclohexane) to far-red region (714 nm in dimethyl sulfoxide) and a high-temperature sensitivity (-0.23 nm °C-1). These, together with unique basicity and acido-/vaporchromism upon acidification elucidated by NMR and photospectroscopic studies, show stark contrast to the conventional 7-NEt2-CUM. The new series of these tailored 6-X-CUMs represents a new dimension in tailoring the photophysical properties for the development of a promising class of multistimuli-responsive materials.

Circularly polarized luminescence (CPL) materials have potential applications in 3D optical displays, information security encryption, sensors, and photoelectric devices because of their inherent a...

Biomimetic membrane materials have been widely explored and developed for drug loading and tissue engineering applications due to their excellent biocompatibility and abundant reaction sites. However, novel cytomembrane mimics have been lacking for a long time. In this study, black phosphorus (BP) was used as the foundation for a new generation of promising cytomembrane mimics due to its multiple similarities to cytomembranes. Inspired by the dual function of endotoxins on membranes, we prepared a BP-based cytomembrane mimic with controllable antibacterial ability via electrostatic interaction between BP and [1-pentyl-1-quaternary ammonium-3-vinyl-imidazole]Br ([PQVI]Br). The release of PQVI could be manipulated in different conditions by adjusting the electrostatic force, thereby achieving controllable antibacterial ability. This report confirms the possibility of using BP as a new material to mimic cytomembranes and provides a new concept of controllable antibacterial action based on endotoxins.

Supramolecular self-assemblies and co-assemblies possess multiple noncovalent interactions, highly ordered structures, and multifunctional properties. Yet, the fundamental understanding of their "structure-property relationship" remains very challenging. Herein, two kinetically controlled supramolecular charge transfer (CT) complexes were conceptualized from a trimorphic molecular donor denoted as "twisted aromatic hydrocarbon" (TAH), with p-fluoranil (TFQ) and p-chloranil (TCQ) in water, organic solvent, and solvent-free methods. Elucidating their co-assembling mechanism revealed that segmentation of the TAH with molecules having planar deficient cores spontaneously formed a distinct "H-type mixed stack" and "J-type segregated stack", regulated by blue/red-shifted charge-transfer and π-π stacking including weak C-H···F and C-H···O noncovalent interactions. By utilizing the structural transformational ability of the self-assembled TAH, the mechanistic aspects for the rapid nanoscopic co-assembly formation were precisely demonstrated experimentally and theoretically. The trimorphs and co-crystals of TAH could be disassembled resulting in turn-on emission by applying various external stimuli and being repeatedly reconfigured, thus providing a unique structure-property relationship and new TAH-based materials. This unique concept offers color-specific polymorphism and CT-complex formation strategy involving a simple class of functional materials having cooperative network forming ability using the twisted molecular donor.

The widespread occurrence of infections from multidrug-resistant (MDR) bacteria is a global health problem. It has been amplified over the past few years due to the increase in adaptive traits in bacteria and lack of advanced treatment strategies. Because of the low bioavailability and limited penetration at infected sites, the existing antibiotics often fail to resist bacterial growth. Recently, developed stimuli-responsive drug delivery systems and combinatorial therapeutic systems based on nanoparticles, metal-organic frameworks, hydrogels, and organic chromophores offer the ability to improve the therapeutic efficacy of antibiotics by reducing drug resistance and other side effects. These therapeutic systems have been designed with the relevant chemical and physical properties that respond to specific triggers resulting in spatiotemporal controlled release and site-specific transportability. This review highlights the latest development of single and dual/multistimuli-responsive antibiotic delivery systems for combination therapies to treat MDR bacterial infections and biofilm eradication.

Soft photonic materials formed from nanoscale colloidal crystals are versatile platforms for sensing and signaling in biomedical, chemical, and mechanical application scenarios. A particularly leve...

Inspired by the coloring mechanism of insects, we demonstrated the preparation of metallic luster materials by a combination of dye absorption and specular reflection from layered microcrystals. Me...

Development of smart switchable surfaces to solve the inevitable bacteria attachment and colonization has attracted much attention; however, it proves very challenging to achieve on-demand regeneration for noncontaminated surfaces. We herein report a smart, host-guest interaction-mediated photo/temperature dual-controlled antibacterial surface, topologically combining stimuli-responsive polymers with nanobactericide. From the point of view of long-chain polymer design, the peculiar hydration layer generated by hydrophilic poly(2-hydroxyethyl methacrylate) (polyHEMA) segments severs the route of initial bacterial attachment and subsequent proliferation, while the synergistic effect on chain conformation transformation poly(N-isopropylacrylamide) (polyNIPAM) and guest complex dissociation azobenzene/cyclodextrin (Azo/CD) complex greatly promotes the on-demand bacterial release in response to the switch of temperature and UV light. Therefore, the resulting surface exhibits triple successive antimicrobial functions simultaneously: (i) resists ∼84.9% of initial bacterial attachment, (ii) kills ∼93.2% of inevitable bacteria attack, and (iii) releases over 94.9% of killed bacteria even after three cycles. The detailed results not only present a potential and promising strategy to develop renewable antibacterial surfaces with successive antimicrobial functions but also contribute a new antimicrobial platform to biomedical or surgical applications.

Radical anions are important for various uses. However, their generation and stabilization under ambient conditions, which are essential for actual applications, are challenging. A photogenerated N...

With the incessant improvement of requirements for optical anti-counterfeiting technology, it is essential to develop multifunctional luminescent materials with multiple models and adjustable lumin...

Over the past few decades, advanced polymeric materials have gained popularity in the development of sustainable agricultural applications. Smart polymeric systems have extensively contributed to the agricultural industry by increasing the efficiency of pesticides, herbicides, and fertilizers by facilitating controlled release systems and, therefore, enabling lower doses to be used. Superabsorbent polymeric materials have been used as soil conditioners to control the impact of drought, whereas polycationic polymers have been utilized for plant bioengineering. These functions in the environment are complemented by applications within plants as part of the developing range of tools for genetically transforming plants in order to increase productivity and disease resistance. This Review will summarize and discuss the recent developments in the design and application of advanced polymeric systems for precision agriculture related applications. The design criteria of the polymers employed to date, such as polymer structure, as well as the properties of polymer nanoparticles including shape and size will be discussed, and the key findings in the related area will be highlighted. Finally, we will identify future directions for the exploration of functional polymers with the ultimate aim of advancing sustainable agriculture.\ud \ud

This study presents dual-responsive colloidal microgels to repair nonwoven fiber mats (NWFs) and recover their native morphological and functional properties. The formulation comprises poly(N-isopr...

Hydrogels serving as a drug carrier was realized by entrapping small-sized drug molecules within their cross-linked interstitial networks. After covering the targeted location, hydrogels interact with the physiological fluids and swell, resulting in an increased interspace between networks for the outside diffusion of drugs. However, inevitable in vivo inflammatory responses or bacterial infection on the implant materials and persistent cargo release are still challenging. Herein, we report the fabrication of dual-responsive hydrogels based on acid-sensitive poly(ethylenimine) (PEI) derivative (PEI(-COOH/-vinyl)), thiol-responsive camptothecin prodrug monomer (CPTM), and hydrophilic oligo(ethylene glycol) methyl ether acrylate (OEGMA) by a conventional radical polymerization. Curcumin was then solubilized into the hydrogels to endow them with antimicrobial and cancer resistance properties. The in vitro experiments exhibited sustained hydrogel dissolution and CPT release in a simulated physiological environment. The antimicrobial and cytotoxicity tests of drug-loaded hydrogels using methicillin-resistant

An easy one-pot method is utilized for the synthesis of carbon nanodots, which has been investigated primarily from material perspectives. However, this preferred one-pot synthesis method suffers f...

Stimuli-responsive emulsifiers have emerged as a class of smart agents that can permit regulated stabilization and destabilization of emulsions, which is essential for food, cosmetic, pharmaceutical, and petroleum industries. Here, we report the synthesis of novel "smart" hydroxyapatite (HaP) magnetic nanoparticles and their corresponding stimuli-responsive Pickering emulsions and explore their movement under confined spaces using a microfluidic platform. Pickering emulsions prepared with our magnetic stearic acid-functionalized Fe2O3@HaP nanoparticles exhibited pronounced pH-responsive behavior. We observed that the diameter of emulsion droplets decreases with an increase in pH. Swift demulsification was achieved by lowering the pH, whereas the reformation of emulsions was achieved by increasing the pH; this emulsification-demulsification cycling was successful for at least ten cycles. We used a microfluidic platform to test the stability of the emulsions under flowing conditions and their response to a magnetic field. We observed that the emulsion stability was diminished and droplet coalescence was enhanced by the application of the magnetic field. The smart nanoparticles we developed and their HaP-based emulsions present promising materials for pharmaceutical and petroleum industries, where responsive emulsions with controlled stabilities are required.

Metal substrates beneath polymeric coatings are susceptible to localized corrosion, which could result in lifetime reduction and catastrophic failure without timely repair treatment. In situ detection of corrosion and repair coating defects are in high demand yet challenging to fulfill so far. Herein, we report a smart polymeric coating by integrating nanosensors into the coating matrix, which is capable of efficient corrosion sensing and active anticorrosion protecting. The nanosensors were constructed by zeolitic imidazolate framework encapsulated with the polyethylene glycol-tannic acid complex. The morphology, chemical constitution, and stimulus responsiveness of nanosensors were systematically analyzed. The generation of local corrosion beneath coating can be promptly sensed and reported by a conspicuous purple color derived from tannic-iron ion coordinates. Meanwhile, local electrochemical impedance spectroscopy results proved that the metal degradation process at the defected interface can be largely inhibited, exhibiting active anticorrosion property. Furthermore, the constructed smart coating possessed superior impermeability and long-term protective performance under simulated seawater and harsh salts spray conditions. This feasible and effective strategy based on simple nanosensors to engineer smart coatings paves a new way to develop high environmental adaptability protective materials with protecting, corrosion sensing, and self-healing functions.

Light- and temperature-responsive poly(N-isopropylacrylamide-co-nitrobenzyl methacrylate) (pNIPAm-co-NBMA) microgels were synthesized via free-radical precipitation polymerization and exhibited a h...

A series of N,N′-dialkylimidazolium room temperature ionic liquids (RTILs) with nonafluorobutanesulfonate ([Cnmim][NFBS], n = 5–8) were synthesized and characterized by elemental analysis, NMR, SCX...

Carbon nanotubes (CNTs) have high photothermal conversion efficiency and hence can be used to prepare light-absorbing nanocomposites with polymers. In this study, an interesting type of nanocomposi...

Smart materials possess a high potential for application in process engineering. Among these smart materials, stimuli-responsive hydrogels exhibit the chemically inherent characteristic to signific...

Smart insulin delivery platforms having the ability of mimicking pancreatic cells are highly expected for diabetes treatment. Herein, a smart glucose-sensitive insulin delivery platform on the basis of transcutaneous microneedles has been designed. The as-prepared microneedles are composed of glucose- and pH-responsive supramolecular polymer vesicles (PVs) as the drug storage and water soluble polymers as the matrix. The well-defined PVs are constructed from the host-guest inclusion complex between water-soluble pillar[5]arene (WP5) with pH-responsiveness and paraquat-ended poly(phenylboronic acid) (PPBA-G) with glucose-sensitivity. The drug-loaded PVs, including insulin and glucose oxidase (GOx) can quickly respond to elevated glucose level, accompanied by the disassociation of PVs and fast release of encapsulated insulin. Moreover, the insulin release rate is further accelerated by GOx, which generates gluconic acid at high glucose levels, thus decreasing the local pH. Therefore, the host-guest interaction between WP5 and PPBA-G is destroyed and a total structure disassociation of PVs takes place, contributing to a fast release of encapsulated insulin. The in vivo insulin delivery to diabetic rats displays a quick response to hyperglycemic levels and then can fast regulate the blood glucose concentrations to normal levels, which demonstrates that the obtained smart insulin device has a highly potential application in the treatment of diabetes.

Functional capsule polymer particles have a variety of interesting applications, including stimuli-responsive delivery systems; however, a major drawback is that conventional fabrication methods ty...

Luminescent solar concentrators (LSCs) consist of dye-doped, highly transparent, plastic plates aimed at improving the building integration and reducing the cost of photovoltaic (PV) technology. In...

Hydrogen peroxide (H2O2) is widely involved in various physiological or pathological processes such as cell differentiation, proliferation, tumorigenesis, and immune responses. The accurate detection of H2O2 is highly required in many situations ranging from chemical sensing to biomedical diagnosis. However, it is exceedingly challenging to develop a single sensor that can respond to H2O2 in different conditions. Herein, a three-in-one stimulus-responsive nanoplatform (Au@MnO2@Raman reporter) was designed for colorimetry/SERS/MR tri-channel H2O2 detection which satisfied different applications. The MnO2 shell acted as a distance mediator between the gold nanoparticle (Au NP) core and the Raman reporter layer. In the presence of H2O2, the MnO2 shell is degraded, thus releasing the Mn2+ and Au NP core, which act as magnetic resonance (MR) and colorimetry signals, respectively. Simultaneously, the Raman reporters adsorb on the exposed Au NPs, resulting in the surface-enhanced Raman scattering (SERS) effect. The Au NP-based colorimetric assay was employed as H2O2 sensors for glucose detection while the turn-on signals of SERS and MR were used for H2O2 sensing and imaging in live cells and tumors, showing great versatility and flexibility of the multichannel probes in diverse situations.

We demonstrate microfluidic manufacturing of glutathione (GSH)-responsive polymer nanoparticles (PNPs) with controlled

Precise control over self-assembly of peptides into adaptable nanostructures allows for emulating the dynamic organization of natural proteins and their sophisticated biological functions. Utilization of disease biomarkers as internal stimuli for manipulating the self-assembly of peptides bestows their adaptable features with a spatiotemporal resolution to satisfy the requirement of the performance of biomaterials. Reactive oxygen species (ROS) consisting of reactive ions or free radicals are overexpressed by pathological lesions and have been recognized as one of conventional biomarkers for disease progression. Despite the progress made over the past decade in stimulus-responsive self-assembly of peptides as well as the summarization of this progress, the specific reviews focusing on ROS-responsive self-assembly of peptides remain scarce. This review summarizes the progress achieved over the past decade of the ROS-responsive self-assembly of peptides into adaptable nanostructures and their applications in biomaterials. We focus on the chemical sources responsible for the ROS-sensitive behavior of peptides, in which the chemical moieties are incorporated into peptides as side chains, terminal groups, or backbone linkages. The ROS-responsive self-assembly of peptides into nanostructures with morphologies adaptable to ROS-oxidation and their applications in enzymatic catalysis, chemosensing, drug delivery, and tissue engineering will be highlighted. Understanding the established ROS-responsive peptide self-assembling systems allows us to provide perspectives for their further development and thereby elucidate their great potential in development of advanced biomaterials.

Oligonucleotide–nanoparticle conjugates are promising building blocks for stimuli responsive, reconfigurable functional materials in wet environments. Here, we demonstrate the self-assembly of DNA-...

Multimodal stimuli-responsive heterotelechelic poly(2-isopropyl-2-oxazoline) (TPE-PiPrOx-R6G) bearing tetraphenylethene (TPE) and rhodamine 6G (R6G) at the α and ω terminals, respectively, was synt...

It has been a significant challenge to prepare multiple-response hydrogels with both lower critical solution temperature (LCST) and upper critical solution temperature (UCST). This work reports the...

The self-assembly of a stimuli-responsive amphiphilic polymer has been of great interest in the area of targeted drug delivery applications. In this article, a new amphiphilic polyurethane with a hydrophobic backbone consisting of a redox-responsive self-immolative unit and hydrophilic pendant triethylene glycol, which is periodically grafted on the backbone by a tertiary amine group, has been designed and synthesized. This amphiphilic polymer self-assembles into a micellar nanostructure (investigated by dynamic light scattering and transmission electron microscopy) in an aqueous medium and shows guest encapsulation property. Furthermore, the pH-responsive nature leads to the formation of a positively charged nanoassembly at a tumor-relevant pH (∼6.5-6.8), which is probed by zeta potential measurements. As the backbone was constructed with self-immolative, redox-responsive functionality, degradation of the polymer was observed in the presence of a reducing agent, glutathione (GSH), which results in disassembly of the self-assembled structure followed by guest release as probed by UV-vis spectroscopy. The triggered degradation and pH-specific charge generation (from neutral to positive), we believe, will have implications in the design of biodegradable polymers as supramoleular scaffolds for biomedical applications.

The occasional use of chemical warfare agents (CWAs) by rogue states in current conflicts provides a reminder that these hazards are a real threat. Although hazmat suits made of fully impermeable b...

Circulating fetal nucleated cells (CFCs) carrying whole genomic coding of the fetus in maternal blood have been pursued as ideal biomarkers for noninvasive prenatal testing (NIPT). However, a significant limitation is the need to enrich sufficient cells in quantity and purity for fetal genetic disorder diagnosis. This study for the first time demonstrates a stimuli-responsive ligand enabling interface on array patterned microfluidic chip (NIPT-Chip) for high efficient isolation and release of CFCs in untreated whole blood. Deterministic lateral displacement (DLD)-array was patterned in the chip to increase collision frequency between CFCs and surface-anchored antibody to achieve high efficient cell capture. More importantly, the stimuli-responsive interface enables gentle release of captured CFCs through a thiol exchange reaction for downstream gene analysis of NIPT. With the advantages of simple processing, efficient isolation, and gentle release, NIPT-Chip offers great potential for clinical translation of circulating fetal cell-based NIPT.

Two-dimensional (2D) metal–organic frameworks (MOFs) play an essential role in response to external stimuli by changing their physical or chemical properties. This Review mainly aims at the recent ...

Variable stiffness materials are an important class of materials that are useful in soft robotics, reconfigurable devices, deployable vehicles, and artificial muscles. Most variable stiffness polym...

A recent approach in the treatment of diseased cells/tissues is the use of smart, stimuli-responsive nanomaterials. Well-known examples include photosensitizer agents that after light irradiation at a specific wavelength generate singlet oxygen species (strongly cytotoxic) or self-assembled supramolecular structures, which blow up cancer cells by releasing their payload upon an external stimulus, thus making cancer cells swell and burst (so-called "nanobombs"). In this work we synthesized and characterized a polymeric star-like pentaporphyrin system (5P) that, depending on the photoexcitation wavelength selected, can act either as a photosensitizer or as a nanobomb. The 5P compound was characterized by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, nuclear magnetic resonance, UV-vis, and fluorescence spectroscopy techniques. The hydrodynamic size of the 5P compound in physiological buffer solution, as determined by dynamic light spectroscopy, pointed to the formation of aggregates. The toxicity and the blow-up capability of 5P were tested on human neuroblastoma (SH-SY5Y cell line). Results demonstrated that the 5P system can work as a light-triggered nanobomb for targeted cell death. In fact, while the cell's treatment with the compound in the darkness did not induce cell toxicity, the 5P irradiation with laser light at wavelengths of 458 or 405 nm resulted in the generation of singlet oxygen species or a true explosion in a cellular environment, respectively.

Dynamic G-quadruplex hydrogel is engineered by using guanosine, 2-formylphenylboronic acid, and 4-Arm PEG-NH2. The gelation conditions are optimized by varying concentrations of the gelators, pH, a...

Optical imaging-guided chemo-photothermal combination therapy of cancers has attracted considerable attention, because of its capacity for personalized, precision treatment and its synergistic chem...

The stimuli-responsive conformational transformation of peptides possessing a constrained form triggered by specific biological microenvironment would provide an effective strategy for the development of highly specific peptide therapeutics. Here, we developed a peptide containing a cytotoxic helical KLA sequence with therapeutic specificity through the use of stimuli-responsive conformational transformation. The KLA peptide is modified to form a cyclic structure to allow for constrained helicity that confers low cytotoxicity. The modified KLA peptide is electrostatically complexed to hyaluronic acid to facilitate enhanced endocytosis into the cancer cells. After endocytosis, the peptide is released from the complex into the cellular cytoplasm by hyaluronidases on the surface of the cellular membrane. Specific intracellular stimuli then trigger the release of the strain that suppresses peptide helicity, and the inherent helical conformation of the KLA peptide is restored. Therefore, the stimuli-responsive conformational transformation of a peptide from low to high helicity selectively induces cell death by disruption of the plasma and mitochondrial membrane.

We report the assembly of dual-responsive polypeptide nanoparticles loaded with indocyanine green (ICG) using a mesoporous silica (MS) templating method for photothermal and photodynamic therapy. Polypeptide nanoparticles composed of thiol-modified polylysine (PLL) are cross-linked with disulfide bonds and modified with poly(ethylene glycol) (PEG) and pH-sheddable dimethylmaleic anhydride (DMMA), which exhibit reduction- and pH-responsiveness. Cross-linking with disulfide bonds does not influence the free amine groups on PLL chains for further cargo conjugation and surface modification. The stripped DMMA at acidic pH reverses the zeta potential of PLL nanoparticles from negative to positive charge and subsequently results in high cell association. The thermo-responsiveness and singlet oxygen generation of the loaded ICG in DMMA-modified PLL nanoparticles are comparable to those of free ICG under laser irradiation, which induces higher cytotoxicity to cancer cells compared to succinic anhydride (SA)-modified PLL nanoparticles that are not pH-responsive. The reported dual-responsive PLL nanoparticles provide a promising platform for improved photothermal and photodynamic therapy.

The use of chemical dispersants is a well-established approach to oil spill remediation where surfactants in an appropriate solvent are contacted with the oil to reduce the oil-water interfacial tension and create small oil droplets capable of being sustained in the water column. Dispersant formulations typically include organic solvents, and to minimize environmental impacts of dispersant use and avoid surfactant wastage it is beneficial to use water-based systems and target the oil-water interface. The approach here involves the tubular clay minerals known as halloysite nanotubes (HNTs) that serve as nanosized reservoir for surfactants. Such particles generate Pickering emulsions with oil, and the release of surfactant reduces the interfacial tension to extremely low values allowing small droplets to be formed that are colloidally stable in the water column. We report new findings on engineering the surfactant-loaded halloysite nanotubes to be stimuli responsive such that the release of surfactant is triggered by contact with oil. This is achieved by forming a thin coating of wax to stopper the nanotubes to prevent the premature release of surfactant. Surfactant release only occurs when the wax dissolves upon contact with oil. The system thus represents an environmentally benign approach where the wax coated HNTs are dispersed in an aqueous solvent and delivered to an oil spill whereupon they release surfactant to the oil-water interface upon contact with oil.

Self-assembled metal-organic architectures have great potential to undergo major structural changes into different architectures. Such molecular transformation is widely applicable to responsive systems like drug delivery and allosteric catalysis. A great number of metal-organic architectures responsive to a specific stimulus have been reported so far. However, interconversion between a pair of distinct metal-organic structures in response to multiple stimuli is rarely reported despite its high versatility. Herein we report multi-stimuli-responsive interconversion between a bowl-shaped and a capsule-shaped self-assembled Zn

Stimuli-responsive particles have gained considerable interest in many fields of materials science. Among the various possible triggers, light is particularly advantageous due to its easy and effic...

Our group has recently developed StimuFrac, a nontoxic stimuli-responsive fracturing fluid consisting on a CO2-reactive polymer which has been shown at the lab-scale to consistently fracture rock c...