Heme-Mimetic Photosensitizer with Iron-Targeting and Internalizing Properties for Enhancing PDT Activity and Promoting Infected Diabetic Wound Healing.

The management of multibacterial infections remains clinically challenging in the care and treatment of chronic diabetic wounds. Photodynamic therapy (PDT) offers a promising approach to addressing bacterial infections. However, the limited target specificity and internalization properties of traditional photosensitizers (PSs) toward Gram-negative bacteria pose significant challenges to their antibacterial efficacy. In this study, we designed an iron heme-mimetic PS (MnO2@Fe-TCPP(Zn)) based on the iron dependence of bacteria that can be assimilated by bacteria and retained in different bacteria strains (Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus) and which shows high PDT antibacterial efficacy. For accelerated wound healing after antibacterial treatment, MnO2@Fe-TCPP(Zn) was loaded into a zwitterionic hydrogel with biocompatibility and antifouling properties to form a nanocomposite antibacterial hydrogel (PSB-MnO2@Fe-TCPP(Zn)). In the multibacterial infectious diabetic mouse wound model, the PSB-MnO2@Fe-TCPP(Zn) hydrogel dressing rapidly promoted skin regeneration by effectively inhibiting bacterial infections, eliminating inflammation, and promoting angiogenesis. This study provides an avenue for developing broad-spectrum antibacterial nanomaterials for combating the antibiotic resistance crisis and promoting the healing of complex bacterially infected wounds.

A Dual-Channel Ca2+ Nanomodulator Induces Intracellular Ca2+ Disorders via Endogenous Ca2+ Redistribution for Tumor Radiosensitization.

Tumor cells harness Ca2+ to maintain cellular homeostasis and withstand external stresses from various treatments. Here, a dual-channel Ca2+ nanomodulator (CAP-P-NO) is constructed that can induce irreversible intracellular Ca2+ disorders via the redistribution of tumor-inherent Ca2+ for disrupting cellular homeostasis and thus improving tumor radiosensitivity. Stimulated by tumor-overexpressed acid and glutathione, capsaicin and nitric oxide are successively escaped from CAP-P-NO to activate the transient receptor potential cation channel subfamily V member 1 and the ryanodine receptor for the influx of extracellular Ca2+ and the release of Ca2+ in the endoplasmic reticulum, respectively. The overwhelming level of Ca2+ in tumor cells not only impairs the function of organelles but also induces widespread changes in the gene transcriptome, including the downregulation of a set of radioresistance-associated genes. Combining CAP-P-NO treatment with radiotherapy achieves a significant suppression against both pancreatic and patient-derived hepatic tumors with negligible side effects. Together, the study provides a feasible approach for inducing tumor-specific intracellular Ca2+ overload via endogenous Ca2+ redistribution and demonstrates the great potential of Ca2+ disorder therapy in enhancing the sensitivity for tumor radiotherapy.

Engineering biomimetic nanosystem targeting multiple tumor radioresistance hallmarks for enhanced radiotherapy.

Tumor cells establish a robust self-defense system characterized by hypoxia, antioxidant overexpression, DNA damage repair, and so forth to resist radiotherapy. Targeting one of these features is insufficient to overcome radioresistance due to the feedback mechanisms initiated by tumor cells under radiotherapy. Therefore, we herein developed an engineering biomimetic nanosystem (M@HHPt) masked with tumor cell membranes and loaded with a hybridized protein-based nanoparticle carrying oxygens (O2) and cisplatin prodrugs (Pt(IV)) to target multiple tumor radioresistance hallmarks for enhanced radiotherapy. After administration, M@HHPt actively targeted and smoothly accumulated in tumor cells by virtue of its innate homing abilities to realize efficient co-delivery of O2 and Pt(IV). O2 introduction induced hypoxia alleviation cooperated with Pt(IV) reduction caused glutathione consumption greatly amplified radiotherapy-ignited cellular oxidative stress. Moreover, the released cisplatin effectively hindered DNA damage repair by crosslinking with radiotherapy-produced DNA fragments. Consequently, M@HHPt-sensitized radiotherapy significantly suppressed the proliferation of lung cancer H1975 cells with an extremely high sensitizer enhancement ratio of 1.91 and the progression of H1975 tumor models with an excellent tumor inhibition rate of 94.7%. Overall, this work provided a feasible strategy for tumor radiosensitization by overcoming multiple radioresistance mechanisms.

Confined Water Dominates Ion/Molecule Transport in Hydrogel Nanochannels.

Current artificial nanochannels rely more on charge interactions for intelligent mass transport. Nevertheless, popular charged nanochannels would lose their advantages in long-term applications. Confined water, an indispensable transport medium in biological nanochannels, dominating the transport process in the uncharged nanochannels perfectly provides a new perspective. Herein, we achieve confined-water-dominated mass transport in hydrogel nanochannels (HNCs) constructed by in situ photopolymerization of acrylic acid (PAA) hydrogel in anodic alumina (AAO) nanochannels. HNCs show selectivity to Na+ transport and a high transport rate of molecules after introducing Na+/Li+, compared with other alkali metal ions like Cs+/K+. The mechanism given by ATR-FTIR shows that the hydrogen-bonding structure of confined water in HNCs is destabilized by Na+/Li+, which facilitates mass transport, but is constrained by Cs+/K+, resulting in transport inhibition. This work elucidates the relationship between confined water and mass transport in uncharged nanochannels while also presenting a strategy for designing functional nanochannel devices.

Mitochondrial Localized In Situ Self-Assembly Reprogramming Tumor Immune and Metabolic Microenvironment for Enhanced Cancer Therapy.

The inherent immune and metabolic tumor microenvironment (TME) of most solid tumors adversely affect the antitumor efficacy of various treatments, which is an urgent issue to be solved in clinical cancer therapy. In this study, a mitochondrial localized in situ self-assembly system is constructed to remodel the TME by improving immunogenicity and disrupting the metabolic plasticity of cancer cells. The peptide-based drug delivery system can be pre-assembled into nanomicelles in vitro and form functional nanofibers on mitochondria through a cascade-responsive process involving reductive release, targeted enrichment, and in situ self-assembly. The organelle-specific in situ self-assemblyeffectively switches the role of mitophagy from pro-survival to pro-death, which finally induces intense endoplasmic reticulum stress and atypical type II immunogenic cell death. Disintegration of the mitochondrial ultrastructure also impedes the metabolic plasticity of tumor cells, which greatly promotes the immunosuppresive TME remodeling into an immunostimulatory TME. Ultimately, the mitochondrial localized in situ self-assembly system effectively suppresses tumor metastases, and converts cold tumors into hot tumors with enhanced sensitivity to radiotherapy and immune checkpoint blockade therapy. This study offers a universal strategy for spatiotemporally controlling supramolecular self-assembly on sub-organelles to determine cancer cell fate and enhance cancer therapy.

Interfacial Water-Dictated Oil Adhesion Based on Ion Modulation.

Oil adhesion on ionic surfaces is ubiquitous in organisms and natural environments and is generally determined by surface chemical component and texture. However, when adhesion occurs, water molecules at the solid-liquid interface, acting as a bridge not only influenced by the structure and composition of the solid surface but also interacting with the neighboring oil molecules, play a crucial role but are always overlooked. Herein, we investigate the oil adhesion process on a carboxyl-terminated self-assembled monolayer surface (COOH-SAM) in ionic solutions and observe the interfacial water structure via surface-enhanced Raman scattering (SERS) in this system. It is found that the lower the tetracoordinated water content, the stronger the oil adhesion. Compared to monovalent ions, the strengthened binding of multivalent ions to the COOH-SAM surface makes the interfacial water more disordered, which eventually leads to a stronger oil adhesion. Notably, the amount of oil adhesion decreases with an increase in the thickness of the interfacial water region. The interfacial water-dictated oil adhesion has been demonstrated in capillary to simulate the water-driven oil recovery, providing a molecular-level explanation for enhanced oil recovery from low salinity water flooding and also indicating potential applications in intelligent microfluidic and seawater desalination.

Low-grade wind-driven directional flow in anchored droplets.

Low-grade wind with airspeed Vwind < 5 m/s, while distributed far more abundantly, is still challenging to extract because current turbine-based technologies require particular geography (e.g., wide-open land or off-shore regions) with year-round Vwind > 5 m/s to effectively rotate the blades. Here, we report that low-speed airflow can sensitively enable directional flow within nanowire-anchored ionic liquid (IL) drops. Specifically, wind-induced air/liquid friction continuously raises directional leeward fluid transport in the upper portion, whereas three-phase contact line (TCL) pinning blocks further movement of IL. To remove excessive accumulation of IL near TCL, fluid dives, and headwind flow forms in the lower portion, as confirmed by microscope observation. Such stratified circulating flow within single drop can generate voltage output up to ~0.84 V, which we further scale up to ~60 V using drop "wind farms". Our results demonstrate a technology to tap the widespread low-grade wind as a reliable energy resource.

Cancer Stem-Like Cells-Oriented Surface Self-Assembly to Conquer Radioresistance.

Cancer stem-like cells (CSCs), capable of indefinite self-renewal and differentiation, are considered to be the root cause of tumor radiotherapy (RT) resistance. However, the CSCs-targeted therapy still remains to be a great challenge because they are commonly located in the deep tumor making drugs hard to approach, and their hypoxic and acidic niche can further aggravate radioresistance. Herein, based on the finding that hypoxic CSCs highly express carbonic anhydrase IX (CAIX) on the cell membrane, a CAIX-targeted induced in situ self-assembly system on the surface of CSC is reported to overcome hypoxic CSC-mediated radioresistance. Via the sequential processes of "monomer release-target accumulation-surface self-assembly", the constructed peptide-based drug delivery system (CA-Pt) exhibits the advantages of deep penetration, amplified CAIX inhibition, and enhanced cellular uptake, which greatly relieves the hypoxic and acidic microenvironment to promote the hypoxic CSC differentiation and combines with platinum to boost the RT-inducing DNA damage. In both lung cancer tumor mouse and zebrafish embryo models, CA-Pt treatment can effectively assist RT in suppressing tumor growth and preventing tumor invasion and metastasis. This study uses a surface-induced self-assembly strategy to differentiate hypoxic CSCs, which may provide a universal treatment strategy for overcoming tumor radioresistance.

Tumor-Specific Peroxynitrite Overproduction Disrupts Metabolic Homeostasis for Sensitizing Melanoma Immunotherapy.

Tumor cells elicit metabolic reprogramming to establish an immunosuppressive tumor microenvironment (TME) for escaping from immunosurveillance. Therefore, interrupting the metabolic adaptation of tumor cells may be a promising strategy for TME immunomodulation, favoring immunotherapy. In this work, a tumor-specific peroxynitrite nanogenerator APAP-P-NO is constructed that can selectively disrupt metabolic homeostasis in melanoma cells. Stimulated by melanoma-characteristic acid, glutathione, and tyrosinase, APAP-P-NO can efficiently generate peroxynitrite through the in situ coupling of the produced superoxide anion and released nitric oxide. Metabolomics profiling reveals that the accumulated peroxynitrite induces a great decrease in metabolites in the tricarboxylic acid cycle. Meanwhile, the glycolysis-produced lactate drops sharply both intracellularly and extracellularly under peroxynitrite stress. Mechanistically, peroxynitrite impairs the activity of glyceraldehyde-3-phosphate dehydrogenase in glucose metabolism through S-nitrosylation. The metabolic alterations effectively reverse the immunosuppressive TME to evoke potent antitumor immune responses, including polarization of M2-like macrophages to M1phenotype, reduction of myeloid-derived suppressor cells and regulatory T cells, and restoration of CD8+ T cell infiltration. Combining APAP-P-NO with anti-PD-L1 achieves a significant inhibition against both primary and metastatic melanomas without systemic toxicities. Collectively, a tumor-specific peroxynitrite overproduction approach is developed and the possible mechanism of peroxynitrite-mediated TME immunomodulation is explored, providing a new strategy for facilitating immunotherapy sensitivity.

Large-Scale Metal-Organic Framework Nanoparticle Monolayers with Controlled Orientation for Selective Transport of Rare-Earth Elements.

Long-range ordered membranes comprised of porous nanoparticles have been pursued in precise separations for a long time. Yet most of the fabrication methods suffer from limited substrates or lack of precise control over crystal orientation. Herein, large-scale metal-organic framework (MOF) monolayer membranes with controlled orientations are prepared through an interfacial self-assembly process confined by superlyophilic substrates. The superspreading of reactant microdroplets results in an ultrathin liquid layer under an immiscible oil as a confined reactor. The concomitant MOF (ZIF-8) particles spontaneously assemble into monolayers with controlled orientations, determined by the particles' contact angles at the liquid/liquid interface, which can be regulated by solvent compositions. Therein both gas-adsorption and ion-transport tests prove that the ⟨111⟩-oriented membrane exhibits a minimized mass-transfer resistance. The as-prepared membrane can selectively transport rare-earth elements (REEs), and a La3+/K+ selectivity of 14.3 is achieved. Molecular dynamics simulations reveal that the REEs-selectivity is associated with the distinct difference in ion-membrane binding energies, demonstrating the potential of ZIF-8 membranes for use in high-efficiency recovery of REEs from industrial wastes.

[Carbonic anhydrase IX-based tumor imaging and therapy: a review].

Carbonic anhydrase IX (CAIX) is a transmembrane protein that is specifically overexpressed on the surface of hypoxic tumor cells. With the function of regulating the acidity of tumor cells both inside and outside, CAIX is closely related to tumor proliferation, invasion and metastasis. Therefore, CAIX is a promising target for tumor imaging and therapy. Herein, we summarized recent advances in CAIX-based tumor imaging, therapy and theranostics, and prospected future applications of using CAIX as an anti-tumor target.

Age- and sex-related differences in cortical morphology and their relationships with cognitive performance in healthy middle-aged and older adults.

Background: The impacts of age and sex on brain structures related to cognitive function may be important for understanding the role of aging in Alzheimer disease for both sexes. We intended to investigate the age and sex differences of cortical morphology in middle-aged and older adults and their relationships with the decline of cognitive function. Methods: In this cross-sectional study, we examined the cortical morphology in 204 healthy middle-aged and older adult participants aged 45 to 89 years using structural magnetic resonance imaging (sMRI) data from the Dallas Lifespan Brain Study data set. Brain cortical thickness, surface complexity, and gyrification index were analyzed through a completely automated surface-based morphometric analysis using the CAT12 toolbox. Furthermore, we explored the correlation between cortical morphology differences and test scores for processing speed and working memory. Results: There were no significant interactions of age and sex with cortical thickness, fractal dimension, or gyrification index. Rather, we found that both males and females showed age-related decreases in cortical thickness, fractal dimension, and gyrification index. There were significant sex differences in the fractal dimension in middle-aged participants and the gyrification index in older adult participants. In addition, there were significant positive correlations between the cortical thickness of the right superior frontal gyrus and Wechsler Adult Intelligence Scale (WAIS)-III Letter-Number Sequencing test scores in males (r=0.394; P<0.001; 95% CI for r values 0.216-0.577) and females (r=0.344; P<0.001; 95% CI for r values 0.197-0.491), respectively. Furthermore, a significant relationship between the gyrification index of the right supramarginal gyrus (SupraMG) and WAIS-III Digit Symbol test scores was observed in older adult participants (r=0.375; P<0.001; 95% CI for r values 0.203-0.522). Conclusions: The results suggest that, compared with males, females have more extensive differences in cortical morphology. The gyrification index of the right SupraMG can be used as an imaging marker of sexual cognitive differences between males and females in older adults. This study helps to further understand sex differences in the aging of the brain and cognition.

ICG-loaded and 125I-labeled theranostic nanosystem for multimodality imaging-navigated phototherapy of breast cancer.

Multimodality imaging-navigated precise phototherapy has been well-established as a promising strategy for enhancing the diagnostic and therapeutic efficiency of cancer in preclinical trials. However, proper theranostic agents with adequate biosafety and biological efficacy as well as simple components and preparations are still in great demand to promote the clinical translation of this regimen. Here, we developed a multifunctional nanosystem based on the self-assembly of FDA-approved indocyanine green (ICG) and 125I-labeled glycopeptides, which were composed of FDA-approved natural polysaccharide sodium alginate and endogenous tyrosine, for fluorescence imaging/single photon emission computed tomography (FLI/SPECT)-guided synergistic photothermal/photodynamic therapy (PTT/PDT) of breast cancer. The as-prepared ICG@ADY(125I) NPs possessed a stable nanostructure and radiolabel, an ICG-equivalent ROS and hyperthermia generation property, and a preferable photo/photothermal stability and biocompatibility, favoring its tumor homing, multimodality imaging, and phototherapy with high biosafety. Consequently, ICG@ADY(125I) NPs smoothly accumulated in tumors by virtue of their long blood circulation (t1/2 = 15.76 ± 1.34 h) and the EPR effect, thereby presenting highly sensitive FLI/SPECT images to realize cancer diagnosis. Guided by multimodality imaging, accurate PTT/PDT was performed using NIR laser irradiation, achieving a high tumor inhibition rate (81.8%) against 4T1 breast cancer models without appreciable side effects. Altogether, this theranostic nanosystem may have huge potential for the clinical diagnosis and treatment of breast cancer.

Supramolecular Coassembled Peptide Hydrogels for Efficient Anticancer Therapy by RNS-Based PDT and Immune Microenvironment Regulation.

Photodynamic therapy (PDT) has attracted much attention in cancer treatment due to its tumor selectivity and noninvasive nature. Recent studies have demonstrated that PDT mediated reactive oxygen species (ROS) generation in tumor microenvironment (TME) synergistically improves the efficacy of immune checkpoint blockade (ICB) therapy. However, the instability and short half-life of the ROS generated by PDT limit its clinical applications. Herein, a coassembled peptide hydrogel comprising two short peptides that contained the same assembly unit, Ce6-KKFKFEFEF (KEF-Ce6) and RRRRRRRR-KFKFEFEF (KEF-R8) is developed. When exposed to 635 nm laser irradiation, KEF-Ce6 released ROS, while KEF-R8 plays as nitric oxide (NO) donor. Subsequently, ROS reacts with NO to produce reactive nitrogen species (RNS). Both in vitro and in vivo experiments prove that converting ROS into more cytotoxic RNS caused intense cell death. Importantly, it is observed that tumor-associated macrophages (TAMs) are polarized to proinflammatory types (M1-type) by the RNS-based PDT. The increase of M1 macrophages relieves the immunosuppressive situation in TME. Thus, when combined with αPD-L1 treatment, the survival time of tumor-bearing mice is prolonged. Overall, a simple yet efficient coassembled hydrogel that can cascade release ROS/NO/RNS and strengthen antitumor T cell responses to boost cancer immunotherapy by reprogramming TAMs is provided.

Hypertoxic self-assembled peptide with dual functions of glutathione depletion and biosynthesis inhibition for selective tumor ferroptosis and pyroptosis.

Abundant glutathione (GSH) is a biological characteristic of lots of tumor cells. A growing number of studies are utilizing GSH depletion as an effective adjuvant therapy for tumor. However, due to the compensatory effect of intracellular GSH biosynthesis, GSH is hard to be completely exhausted and the strategy of GSH depletion remains challenging. Herein, we report an L-buthionine-sulfoximine (BSO)-based hypertoxic self-assembled peptide derivative (NSBSO) with dual functions of GSH depletion and biosynthesis inhibition for selective tumor ferroptosis and pyroptosis. The NSBSO consists of a hydrophobic self-assembled peptide motif and a hydrophilic peptide derivative containing BSO that inhibits the synthesis of GSH. NSBSO was cleaved by GSH and thus experienced a morphological transformation from nanoparticles to nanofibers. NSBSO showed GSH-dependent cytotoxicity and depletion of intracellular GSH. In 4T1 cells with medium GSH level, it depleted intracellular GSH and inactivated GSH peroxidase 4 (GPX4) and thus induced efficient ferroptosis. While in B16 cells with high GSH level, it exhausted GSH and triggered indirect increase of intracellular ROS and activation of Caspase 3 and gasdermin E, resulting in severe pyroptosis. These findings demonstrate that GSH depletion- and biosynthesis inhibition-induced ferroptosis and pyroptosis strategy would provide insights in designing GSH-exhausted medicines.

Circadian humidity fluctuation induced capillary flow for sustainable mobile energy.

Circadian humidity fluctuation is an important factor that affects human life all over the world. Here we show that spherical cap-shaped ionic liquid drops sitting on nanowire array are able to continuously output electricity when exposed to outdoor air, which we attribute to the daily humidity fluctuation induced directional capillary flow. Specifically, ionic liquid drops could absorb/desorb water around the liquid/vapor interface and swell/shrink depending on air humidity fluctuation. While pinning of the drop by nanowire array suppresses advancing/receding of triple-phase contact line. To maintain the surface tension-regulated spherical cap profile, inward/outward flow arises for removing excess fluid from the edge or filling the perimeter with fluid from center. This moisture absorption/desorption-caused capillary flow is confirmed by in-situ microscope imaging. We conduct further research to reveal how environmental humidity affects flow rate and power generation performance. To further illustrate feasibility of our strategy, we combine the generators to light up a red diode and LCD screen. All these results present the great potential of tiny humidity fluctuation as an easily accessible anytime-and-anywhere small-scale green energy resource.

NIR-activated self-sensitized polymeric micelles for enhanced cancer chemo-photothermal therapy.

NIR-activated therapies based on light-responsive drug delivery systems are emerging as a remote-controlled method for cancer precise therapy. In this work, fluorescent dye indocyanine green (ICG)-conjugated and bioactive compound gambogic acid (GA)-loaded polymeric micelles (GA@PEG-TK-ICG PMs) were smoothly fabricated via the self-assembly of the reactive oxygen species (ROS)-responsive thioketal (TK)-linked amphiphilic polymer poly(ethyleneglycol)-thioketal-(indocyanine green) (PEG-TK-ICG). The resultant micelles demonstrated increased resistance to photobleaching, enhanced photothermal conversion efficiency, NIR-controlled drug release behavior, preferable biocompatibility, and excellent tumor accumulation performance. Moreover, upon an 808 nm laser irradiation, the micellar photoactive chromophore ICG converted the absorbed optical energy to both hyperthermia for photothermal therapy (PTT) and ROS as the feedback trigger to the micelles for the tumor-specific release of GA, which could serve as not only a chemotherapeutic drug to directly kill tumor cells but also a heat shock protein 90 (HSP90) inhibitor to realize the photothermal sensitization. As a result, an extremely high tumor inhibition rate (97.9%) of mouse 4 T1 breast cancer models was achieved with negligible side effects after the chemo-photothermal synergistic therapy. This NIR-activated nanosystem with photothermal self-sensitization function may provide a feasible option for the effective treatment of aggressive breast cancers.

Abnormal Properties of Low-Dimensional Confined Water.

Water molecules confined to low-dimensional spaces exhibit unusual properties compared to bulk water. For example, the alternating hydrophilic and hydrophobic nanodomains on flat silicon wafer can induce the abnormal spreading of water (contact angles near 0°) which is caused by the 2D capillary effect. Hence, exploring the physicochemical properties of confined water from the nanoscale is of great value for understanding the challenges in material science and promoting the applications of nanomaterials in the fields of mass transport, nanofluidic designing, and fuel cell. The knowledge framework of confined water can also help to better understand the complex functions of the hydration layer of biomolecules, and even trace the origin of life. In this review, the physical properties, abnormal behaviors, and functions of the confined water are mainly summarized through several common low-dimensional water formats in the fields of solid/air-water interface, nanochannel confinement, and biological hydration layer. These researches indicate that the unusual behaviors of the confined water depend strongly on the confinement size and the interaction between the molecules and confining surface. These diverse properties of confined water open a new door to materials science and may play an important role in the future development of biology.

Microchannel and Nanofiber Array Morphology Enhanced Rapid Superspreading on Animals' Corneas.

The dynamic spreading phenomenon of liquids is vital for both understanding wetting mechanisms and visual reaction time-related applications. However, how to control and accelerate the spreading process is still an enormous challenge. Here, a unique microchannel and nanofiber array morphology enhanced rapid superspreading (RSS) effect on animals' corneas with a superspreading time (ST) of 830 ms is found, and the respective roles of the nanofiber array and the microchannel in the RSS effect are explicitly demonstrated. Specifically, the superspreading is induced by in-/out-of-plane nanocapillary forces among the nanofiber array; the microchannel is responsible for tremendously speeding up the superspreading process. Inspired by the RSS strategy, not only is an RSS surface fabricated with an ST of only 450 ms, which is, respectively, more than 26 and 1.8 times faster than conventional superamphiphilic surfaces and animal's corneas and can be applied as RSS surfaces on video monitors to record clear videos, but also it is demonstrated that the RSS effect has tremendous potential as advanced ophthalmic material surfaces to enhance its biocompatibility for clear vision.

Bioinspired Ultrafast-Responsive Nanofluidic System for Ion and Molecule Transport with Speed Control.

The design of an intelligent nanofluidic system for regulating the transport of substances such as ions and molecules is significant for applications in biological sensing, drug delivery, and energy harvesting. However, the existing nanofluidic system faces challenges in terms of an uncontrollable transport speed for molecules and ions and also a complex preparation processes, low durability, and slow response rate. Herein, we demonstrate the use of a bioinspired ferrofluid-based nanofluid that can facilitate multilevel ultrafast-responsive ion and molecule transport with speed control. Specifically, we reversibly deform bulk ferrofluids using a magnet and wet/dewet the outer surface of superhydrophilic nanochannels for building a smart transport system. By changing the direction and strength of the external magnetic field, a speed control, ultrafast-responsive molecular transport (<0.1 s), and controlled current gating ratio are achieved owing to the different pattern changes of ferrofluids on the outer surface of nanochannels. We also illustrate a practical application of this strategy for antibacterial devices to control the transport of drug molecules in a programmed manner. These results suggest that molecule transport can be further complexified and quantified through an intelligent nanofluidic system.