Sensitive Response Research Articles

Effects of elevated intraocular pressure on alpha ganglion cells in experimental glaucoma mice

Glaucoma is a leading cause of blindness worldwide and glaucoma patients exhibit an early diffuse loss of retinal sensitivity followed by focal loss of RGCs. Combining some previous published results and some new data, this paper provides our current view on how high IOP (H-IOP) affects the light response sensitivity of a subset of RGCs, the alpha-ganglion cells (αGCs), as well as their presynaptic bipolar cells (DBCs and HBCs) and A2 amacrine cells (AIIACs) in dark-adapted mouse retinas. Our data demonstrate that H-IOP in experimental glaucoma mice significantly decreases light-evoked spike response sensitivity of sONαGCs and sOFFαGCs (i.e., raises thresholds by 1.5–2.5 log units), but not that of the tONαGCs and tOFFαGCs. The sensitivity loss in sONαGCs and sOFFαGCs is mediated by a H-IOP induced suppression of AIIAC response which is caused by a decrease of transmission efficacy of the DBCR→AIIAC synapse. We also provide evidence supporting the hypothesis that BK channels in the A17AC→DBCR feedback synapse are the H-IOP sensor that regulates the DBCR→AIIAC synaptic efficacy, as BK channel blocker IBTX mimics the action of H-IOP. Our results provide useful information for designing strategies for early detection and possible treatments of glaucoma as physiological changes occur before irreversible structural damage.

Electrochemical biosensor based on Au5Ir@graphene quantum dot nanocomposite and DNA walker for detection of atrazine in environmental water with extremely high sensitivity and selectivity

Existing electrochemical sensors are inadequate for detecting pesticides at extremely low level. This study presents an electrochemical biosensor based on gold-iridium alloy (Au5Ir) and DNA walker for detection of atrazine. Au5Ir@RFBP-GQD nanocomposite was synthesized via the reduction of chloroauric acid and iridium trichloride using arginine and folic acid-functionalized boron and phosphorus-doped graphene quantum dot (RFBP-GQD). The synergy between Au and Ir, along with the formation of Schottky heterojunction, enhances the catalytic activity. The Au5Ir was covalently conjugated with hairpin DNA and thionine forming a redox probe that was used to construct the electrochemical biosensor for atrazine detection, coupled with a DNA walker mechanism. Atrazine triggers the DNA walker, leading to the introduction of multiple redox probes onto the gold electrode surface. The oxidation and reduction of thionine molecules within these redox probes elicit highly sensitive electrochemical response. The integration of Au5Ir@RFBP-GQD catalysis with the DNA walker results in significant signal amplification. The biosensor exhibits superior sensitivity and selectivity compared to other atrazine sensors, with a linear detection range from 1×10−18 to 1×10−12 M and a low detection limit of 3.4×10−19 M (S/N=3). The proposed analytical method was successfully used for detection of atrazine in environmental water.

3D-Printed Multi-Axis Alignment Airgap Dielectric Layer for Flexible Capacitive Pressure Sensor

Flexible pressure sensors are increasingly recognized for their potential use in wearable electronic devices, attributed to their sensitivity and broad pressure response range. Introducing surface microstructures can notably enhance sensitivity; however, the pressure response range remains constrained by the limited volume of the compressible structure. To overcome this limitation, this study implements an aligned airgap structure fabricated using 3D printing technology. This structure, designed with a precisely aligned triaxial airgap configuration, offers high deformability under pressure, substantially broadening the pressure response range and improving sensitivity. This study analyzes the key structural parameters—the number of axes and pore size—that influence the compressibility and stability of the dielectric material. The results indicate that the capacitive pressure sensor with an aligned airgap structure, manufactured via 3D printing, exhibits a wide operating pressure range (50 Pa to 500 kPa), rapid response time (100 ms), wide limit of detection (50 Pa), and approximately 21 times enhancement in sensitivity (~0.019 kPa−1 within 100 kPa) compared with conventional bulk structures. Furthermore, foot pressure monitoring trials for wearable sensor applications demonstrated exceptional performance, indicating the sensor’s suitability as a wearable device for detecting plantar pressure. These findings advocate for the potential of 3D printing technology to supplant traditional sensor manufacturing processes.

A Combined Lifestyle Intervention Induces a Sensitization of the Blood Transcriptomic Response to a Nutrient Challenge

A Combined Lifestyle Intervention Induces a Sensitization of the Blood Transcriptomic Response to a Nutrient Challenge

Cariogenic potential of the Streptococcus mutans Cid/Lrg system: an in vivo animal case study.

In our prior study using a dual-species (Streptococcus mutans/Streptococcus gordonii) competitive mouse caries model to investigate the contribution of S. mutans LrgAB to in vivo fitness, S. mutans wild-type and ΔlrgAB mutants consistently outnumbered S. gordonii and had high caries scores, even though the ΔlrgAB mutant is highly sensitive to oxidative stress. To determine whether the highly cariogenic sucrose diet used in the previous study masked the contribution of LrgAB to competitive fitness of S. mutans against S. gordonii, we recapitulated our previous mouse caries experiment with a modification in which 4% sucrose drinking water was replaced with sterile water, hypothesized to decrease the frequency of exposure of mice to sucrose, a determinant in the cariogenicity of S. mutans. Given that both S. mutans ΔlrgAB and ΔcidB mutants are sensitive to oxidative stress and share similar transcriptional profiles, these strains, as well as wild-type UA159, were tested in this modified dual-species mouse caries model. When comparing between groups the colonization within molar dental biofilms of S. mutans strains, ΔlrgAB mutant was at a level similar to the wild type, whereas S. mutans ΔcidB was modestly lower than both wild-type and S. mutans ΔlrgAB. The severity of total sulcal caries in both the ∆cidB and ∆lrgAB mutant infections was significantly lower than that of wild type. These results demonstrate that the Cid/Lrg system aids in S. mutans fitness against S. gordonii and caries potential in vivo, a phenotype likely masked in our previous study by more frequent exposure to sucrose.IMPORTANCEThe development of a mature biofilm on the tooth surface is the central event in the pathogenesis of dental caries, which primarily requires that cariogenic organisms withstand the limited resources or environmental fluctuations experienced in the oral cavity. The sensitive and heterogeneous response of the cid and lrg operons to complex external signals has been hypothesized to trigger differentiation of the Streptococcus mutans biofilm community into distinct functional subpopulations to promote survival and persistence of the S. mutans community when challenged by an unfavorable environment. The study described herein enlightens our understanding of how Cid/Lrg contributes to S. mutans pathogenic potential in vivo (caries development), warranting further research regarding the adaptive role of Cid/Lrg system in human oral biofilms toward the development of anti-caries strategies directed at the Cid/Lrg system.

Artificial intelligence for children: UNICEF's policy guidance and beyond

AbstractThis policy review introduces the Policy Guidance on Artificial Intelligence (AI) for Children, produced by the United Nations Children's Fund (UNICEF). This Policy Guidance is the first international‐level output to boost the development of child‐centred AI and relevant policies. A main contribution of this Policy Guidance is that it outlines the foundations, requirements and specific recommendations for developing child‐centred AI and surrounding policies. The shortcomings of this Policy Guidance are also introduced, especially the insufficient gender responsiveness and age sensitivity, plus relatively low representation of the developing world. Possible suggestions for future updates of the Policy Guidance and improving policies on child‐centred AI are provided in this review, such as the inclusion of a broader age range of children during the consultation process. The coexistence of contributions and limitations of this Policy Guidance reflects the situation of development of child‐centred AI and relevant policies, which is currently immature but promising.

Stearoyl CoA desaturase inhibition can effectively induce apoptosis in bladder cancer stem cells

Bladder cancer stands as one of the most prevalent cancers worldwide. While our previous research confirmed the significant role of stearoyl-CoA desaturase (SCD) in bladder cancer, the underlying reasons for its abnormal overexpression remain largely unknown. Moreover, the distinct response to SCD inhibitors between cancer stem cells (CSCs) and adherent cultured cell lines lacks clear elucidation. Therefore, in this experiment, we aim to conduct an analysis and screening of the SCD transcription start site, further seeking critical transcription factors involved. Simultaneously, through experimental validation, we aim to explore the pivotal role of endoplasmic reticulum stress/unfolded protein response in drug sensitivity among cancer stem cells. Additionally, our RNA-seq and lipid metabolism analysis revealed the significant impact of nervonic acid on altering the proliferative capacity of bladder cancer cell lines.

Wearable Multifunctional Hydrogel for Oral Microenvironment Visualized Sensing Coupled with Sonodynamic Bacterial Elimination and Tooth Whitening.

Bacterial-driven dental caries and tooth discoloration are growing concerns as the most common oral health problems. Current diagnostic methods and treatment strategies hardly allow simultaneous early detection and non-invasive treatment of these oral diseases. Herein, a wearable multifunctional double network hydrogel combined with polyaniline and barium titanate (PANI@BTO) nanoparticles is developed for oral microenvironment visualized sensing and sonodynamic therapy. Due to the colorimetric properties of polyaniline, the hydrogel displays a highly sensitive and selective response for visualized sensing of oral acidic microenvironment. Meanwhile, the barium titanate in the hydrogel efficiently generates reactive oxygen species (ROS) under ultrasound irradiation, realizing non-invasive treatment in the oral cavity. Through bacterial elimination experiments and tooth whitening studies, the hydrogel can achieve the dual effect of effectively inhibiting the growth of cariogenic bacteria and degrading tooth surface pigments. Owing to the visualized sensing of the oral acidic microenvironment and efficient sonodynamic therapy function, the proposed hydrogel system offers a solution for the prevention of caries and tooth whitening, which is promising in developing the biomedical system targeting the simultaneous sensing and therapy for oral diseases.

Monitoring Glutathione Content of the Endoplasmic Reticulum under Scrap Leather-Induced Endoplasmic Reticulum Stress via an Endoplasmic Reticulum-Targeted Two-Photon Fluorescent Probe.

Maintaining tissue homeostasis necessitates the coordinated efforts of various cell types to regulate inflammation. Endoplasmic reticulum (ER) stress, a hallmark of inflammation, exacerbates tissue pathology in various human diseases. Glutathione (GSH), a pivotal regulator of cellular redox balance, controls disulfide bond formation in the ER, thereby shielding cells from oxidative stress. In this study, we developed a two-photon fluorescent probe, ER-GSH, with specific ER targeting and demonstrated its high sensitivity and rapid response to GSH. Experiments conducted on BV2 cells and a mice model of neuroinflammation induced by scrap leather revealed that inflammatory reactions led to ER stress and a substantial reduction in GSH levels. Notably, the anti-inflammatory drug NS-398 effectively inhibited cell inflammation and ER stress by maintaining GSH levels. These findings underscore the potential therapeutic significance of modulating GSH levels to alleviate the impact of neuroinflammation.

Crop growth scenario-based pH/temperature dual-responsive degradable polyurea nano/microcapsules: Smart pesticide delivery and sustainable control of Fusarium crown rot in wheat

Designing smart pesticide delivery systems in response to the environmental factors of disease occurrence is critical to achieving targeted pesticide delivery, improving effective pesticide utilization and reducing environmental pollution. Herein, we prepared a novel chemically degradable pH/temperature dual-responsive polyurea capsule (Pyr@PU). The Pyr@PU was based on the diamine cross-linking agent 2,2-diethoxypropane (DAKT) containing acetal groups unstable to acids and isophorone diisocyanate (IPDI), and the phase change material methyl myristate (melting point: 18°C) was used as the oil phase. Owing to the acetal structure in the capsular shell and methyl myristate in the core, Pyr@PU has excellent acidic pH responsiveness and temperature sensitivity. 95.0 % of the fungicidewas released within 48 h at a weakly acidic condition (pH = 5.0), and the fungicide release rate at 35°C was 3.6 and 10.4 times higher than that at 25°C and 15°C, respectively. Bioactivity assays showed a longer duration of Pyr@PU compared to the commercial emulsion (Pyr EC). The degradation rate of Pyr@PU microcapsules (Pyr@PU-Micro) (64.5 %) was significantly lower than Pyr EC (98.6 %) after 24-h UV irradiation. In the 96-h acute toxicity test, Pyr@PU-Micro (LC50 = 0.695 mg·L−1) exhibited a lower toxicity to zebrafish than the Pyr (LC50 = 0.076 mg·L−1), Pyr EC (LC50 = 0.108 mg·L−1), and commercialized microcapsules (Pyr CS) (LC50 = 0.209 mg·L−1). In summary, the new chemically degradable polyurea microcapsules improved the stability and duration of fungicide efficacy and provided a new solution for the effective control of Fusarium crown rot and the reduction of environmental pollution caused by microplastics.

A comparative analysis of the sensitivity and BOLD contamination of the VASO response at 3 Tesla: ME-DEPICTING vs. ME-EPI readouts

Abstract ‘Non-BOLD fMRI’ data acquired at non-zero echo time (TE) suffer from contamination by the Blood Oxygenation Level Dependent (BOLD) signal due to the unavoidable signal decay caused by transverse relaxation. This contamination further reduces their already low inherent functional sensitivities and makes their correction essential. The Slice-Saturation Slab-Inversion Vascular Space Occupancy (SS-SI–VASO), for instance, cancels out BOLD contributions from VASO data, reflecting cerebral blood volume (CBV) changes, via a dynamic division approach. Alternatively, multi-echo (ME) data provide the possibility of extrapolating to TE=0. Acquisitions at very short TE would minimize the need for such corrections. The center-out EPI variant (‘DEPICTING’) is one such readout which allows for short TE. The ME 2D DEPICTING was compared here against a traditional ME 2D EPI for its sensitivity to functional changes in the VASO signal. The two BOLD-correction schemes were also evaluated. Clear differences in functional sensitivity were observed for the uncorrected VASO data obtained from the first echo, TE1, of the two readouts. VASO data corrected by ME extrapolation were, however, found to be almost identical in their sensitivity for detecting CBV changes for both readouts. An excessively high increase in VASO signal sensitivity observed with the dynamic division correction for both readouts revealed a near-perfect linear dependence on TE of VASO signal changes. This could be attributed to the substantial intravascular BOLD contributions at 3 T. In the present data, extravascular ΔR2* fraction was found to be around ~50–60%. ME extrapolation is, hence, recommended to avoid overestimation of functional CBV changes at commonly used TEs.

Magnetic sensitive mechanical response in CrSBr and its composite resonators

We study the mechanical response of bulk CrSBr in temperature using a CrSBr string resonator. We observe two abrupt changes in eigenfrequency and quality factor of the resonator with decreasing temperature, a strong one around 140 K due to an antiferromagnetic phase transition, and a weaker one around 200 K possibly related to a change of spin correlations. We find that the antiferromagnetic transition persists through a temperature window of 30 K rather than showing a narrow sharp change, indicating a gradual spin transition process. In addition, the quality factor exhibits an unexpected increase during the transition, which violates the theoretical prediction. Finally, we demonstrate that in a CrSBr/SiN composite resonator, its vibrational state is sensitively affected by the constituent CrSBr layer during the magnetic phase transitions. It reveals the potential of a composite resonator in both controlling its vibration state with and probing phase transitions of its constituent materials. Our study not only enriches the details about the antiferromagnetic phase transition in CrSBr, but also opens up possibility in magnetic sensing and in situ tuning using composite mechanical resonators.

Organohalogenochromism: Toward Colorimetric Detection of Volatile Organic Halogen Compounds

A significant hypsochromic or bathochromic shift of photoabsorption bands of dyes may be observed only in halogenated solvents. Such specific solvatochromism is termed organohalogenochromism (OHC), which has been recently recognized as a photophysical phenomenon. However, few studies have been carried out on the elucidation of OHC and thus there is a limited insight into the mechanism for expression of OHC, although the phenomenon not only is of a great scientific interest in photochemistry, photophysics, analytical chemistry, and synthetic organic chemistry but also has great potential for development of colorimetric detection technique for organohalogen compounds; this technique is expected to be facile operation and simple analysis with sufficient accuracy, high sensitivity, and fast response, and thus allows visualization and real‐time monitoring for toxic volatile organohalogen compounds (VOHCs). In this Concept, we first review OHC of dyes which have been reported so far. Second, the elucidation of OHC based on the interactions between dye and organohalogen molecules are discussed. In particular, we propose the explanation for a pronounced OHC of donor‐π‐acceptor‐type cationic dye from the viewpoint of halogen bond (XB) between halogenated solvents and counter anion of cationic dye. Moreover, an application of organohalogenochromic dyes to colorimetric sensors for VOHCs is presented.

A Flexible Organomagnetic Single-Layer Composite Film with Built-In Multistimuli Responsivity.

Materials possessing multiple properties and functionalities, that can be controlled or modulated by external stimuli, are a central focus of current research in materials sciences due to their potential to significantly enhance various future technological applications. Herein, we report a significant advancement in this field through the development of a smart, multifunctional organomagnetic composite material. By utilizing a thin layer of polydimethylsiloxane (PDMS) and polypyrrole (PPy) precursors, doped with nickel nanoparticles (NiNPs), we have created an innovative organomagnetic, PDMS/PPy/NiNPs (PPN), single-layer composite film that displays multistimuli responsivity. The study presents the first demonstration of a multifunctional flexible, three-component film structure integrating the structural and flexible PDMS component, together with a conductive polymer component and metal-based nanoparticles into a single-layer design, which displays enhanced and unprecedented responsivity properties against multiple different stimuli. Unlike typical stacked multilayered structures, that exhibit one or two functionalities at most, this novel configuration exhibits multiple functionalities, including magnetoresistance, mechanical stress response, piezoresistivity, and temperature change sensitivity. The as-prepared film demonstrates notable magnetoresistance responsivity, with a relative electrical resistance, ΔR/R0, changing under a weak magnetic field and under ambient conditions. The significance of our study lies in the film's versatility, stability, and sensitivity, especially within the physiological temperature range, making it highly relevant for future biomedical applications. Furthemore, the film's sensitivity to mechanical deformation reveals an impressive piezoresistance behavior. Unlike existing multilayer architectures of higher complexity, our single-layer thin film offers a simpler, more flexible, and reliable solution with a broad range of stimuli-sensing capabilities. The significance of this novel multiresponsive composite material is underscored by the growing demand for advanced materials in biomedical devices, magnetic switches, sensors, electronic skin, transistors, and organic spintronic devices. These promising organomagnetic self-standing layers provide a robust platform for future technological innovations.

Simulating Pelvis Kinematics from Belt and Seat Loading in Frontal Car Crash Scenarios: Important Boundary Conditions that Influence the Outcome.

The risk of submarining during automotive crashes, defined by the lap belt sliding off the pelvis to load the abdomen, is predicted to increase in future autonomous vehicles as greater variation in seating position is enabled. Biofidelic tools are required to efficiently design and evaluate new and/or improved safety systems. This study aims to evaluate the pelvis response sensitivity to variations in boundary conditions that directly influence the pelvis loads, deemed important for the submarining outcome, to facilitate a more precise comparison between finite element human body models (FE-HBMs) and post-mortem human subjects (PMHSs). A parameter study, using a one-variable-at-a-time analysis (low/high) of belt friction, seat friction, seat stiffness, and (on/off) for added belt bending stiffness, was performed using a state-of-the-art FE-HBM in four different test scenarios; one stationary, two sleds with upright occupant posture, and one sled with reclined occupant posture. In the stationary scenario, both belt friction and belt bending stiffness influenced the belt folding behavior, which consequently affected the belt-to-pelvis angle at submarining. In the sled scenarios, only seat friction was found to influence the pelvis kinematics and submarining outcome, with the most biofidelic response resulting from both the low (0.2) and high (0.5) friction coefficient depending on the scenario. To reduce uncertainty in boundary conditions affecting the external pelvis loads and increase confidence in FE-HBM to PMHS comparisons, it is recommended that future experiments evaluate the PMHS to seat friction coefficient and that new belt modeling methods that accurately capture belt folding when interacting with soft tissues are developed.

Enhanced casein organohydrogel coating with the liquid metal catalyst for electric leather in human-machine interaction

Leather’s durability and multi-level structure make it an excellent substrate for electronics. Integrating leather with modern electronic technology to create electronic leather is becoming increasingly popular. However, significant challenges remain, such as adhering conductive media to leather, their penetration and dispersion, and the complexity of preparation. This study presents a new strategy for fabricating electronic leather by combining leather with a casein-based organic hydrogel using coating chemistry techniques. This hydrogel is simple to prepare and exhibits excellent biocompatibility and self-adhesive properties, offering a promising approach to overcome these challenges. Here, we designed casein-stabilized core-shell liquid metal-based catalysts and utilized acrylamide (AM), 2-acrylamido-2-methylpropane sulfonic acid (AMPs), CNTs, and glycerol (Gly) to achieve in situ organohydrogel formation on leather under mild conditions (60 s, 25 °C). The resulting organohydrogel-coated material exhibits outstanding stretchability (tensile stress: 70.3 kPa, tensile strain: 1491.8 %), rapid response (423 ms), and high sensitivity (GF: 7.67) as a strain sensor. This substrate can be employed in designing flexible wearable electronic gloves, facilitating seamless information interaction between humans and devices. This innovation demonstrates significant potential in enhancing the functionality of leather as a wearable electronic device. Combining leather’s natural properties with cutting-edge organohydrogel technology is promising to revolutionize the wearable electronics industry, potentially creating highly versatile and multifunctional electronic skins.

Multi-omics analysis identifies PTTG1 as a prognostic biomarker associated with immunotherapy and chemotherapy resistance

BackgroundPituitary tumor-transforming gene 1 (PTTG1) is an important gene in tumour development. However, the relevance of PTTG1 in tumour prognosis, immunotherapy response, and medication sensitivity in human pan-cancer has to be determined.MethodsTIMER, GEPIA, the human protein atlas, GEPIA, TISCH2, and cBioportal examined the gene expression, protein expression, prognostic value, and genetic modification landscape of PTTG1 in 33 malignancies based on the TCGA cohort. The association between PTTG1 and tumour immunity, tumour microenvironment, immunotherapy response, and anticancer drug sensitivity was investigated using GSCA, TIDE, and CellMiner CDB. Molecular docking was used to validate the possible chemotherapeutic medicines for PTTG1. Additionally, siRNA-mediated knockdown was employed to confirm the probable role of PTTG1 in paclitaxel-resistant cells.ResultsPTTG1 is overexpressed and associated with poor survival in most tumors. Functional enrichment study revealed that PTTG1 is involved in the cell cycle and DNA replication. A substantial connection between PTTG1 expression and immune cell infiltration points to PTTG1’s possible role in the tumour microenvironment. High PTTG1 expression is associated with tumour immunotherapy resistance. The process could be connected to PTTG1, which mediates T cell exhaustion and promotes cytotoxic T lymphocyte malfunction. Furthermore, PTTG1 was found to be substantially linked with sensitivity to several anticancer medications. Suppressing PTTG1 with siRNA reduced clone formation and migration, implying that PTTG1 may play a role in paclitaxel resistance.ConclusionPTTG1 shows potential as a cancer diagnostic, prognostic, and chemosensitivity marker. Increased PTTG1 expression is linked to resistance to cancer treatment. The mechanism could be linked to PTTG1’s role in promoting cytotoxic T lymphocyte dysfunction and mediating T cell exhaustion. It is feasible to consider PTTG1, which is expressed on Treg and Tprolif cells, as a new therapeutic target for overcoming immunotherapy resistance.

Grain boundary sensitization kinetics of cold-rolled Al–Mg alloys

As super-saturated solid solutions of Al-Mg, 5XXX series aluminum alloys are susceptible to sensitization via intergranular precipitation of the anodic β-phase, which promotes intergranular corrosion, exfoliation and stress corrosion cracking under environmental conditions. This study presents important updates to a Johnson–Mehl–Avarami–Kolmogorov (JMAK) type model for low-temperature sensitization, correlating the intergranular corrosion response to impingement of locally sensitized regions surrounding discrete β-phase grain boundary precipitates. It is demonstrated that the sensitization response of these alloys can be approached as a combination of two independent contributions: the geometric configuration of grain boundaries passing through the microstructure that are most prone to sensitization, and the rate that these boundaries sensitize due to the formation of the β-phase. This allows for the large sensitization response variations found between nominally identical materials produced by different suppliers, which originate due to a lack of constraints within current cold-rolled plate tempers, to be removed as a sample-dependent linear scaling factor that is separate of the rate kinetics. The JMAK model describes the kinetics of 5xxx series sensitization with excellent accuracy across all data available in the literature. The results of the model imply that sensitization at environmental temperatures proceeds via a site-saturated process, with the β-phase forming on a set density of preferential nucleation sites. It is shown that site-saturation allows for extension of the JMAK model to non-isothermal aging profiles and supports a diffusion pathway dominated by pipe diffusion to the interface followed by precipitate growth via the collector plate mechanism.

Mitochondria-Targeted NIR Ratiometric and Colorimetric Fluorescent Probe for Biothiols Based on a Thiol-Chromene Click Reaction.

In this work, a mitochondria-targeted NIR ratiometric and colorimetric fluorescent probe 1 was tactfully designed and synthesized by a novel design strategy of modifying chromene to pyridine for the first time. 1 exhibited a maximum absorption peak at 508 nm and a maximum fluorescence emission peak at 650 nm. Under the stimulus of biothiols (cysteine (Cys), homocysteine (Hcy), and glutathione (GSH)), the maximum absorption and fluorescence emission peaks of 1 blue-shifted to 448 and 541 nm, respectively, along with color changes from red to yellow under visible light and from red to green under a 365 nm ultraviolet (UV) lamp, which can be ascribed to the click reaction of biothiols with the α,β-unsaturated ketone of the chromene moiety with pyran ring-opening, phenol formation, and 1,6-elimination of the p-hydroxybenzyl moiety. 1 detected biothiols (Cys, GSH, and Hcy) with high sensitivity (LODs of 29, 23, and 16 nM for Cys, GSH, and Hcy, respectively), excellent selectivity, and fast response. Moreover, 1 can target mitochondria and image the fluctuation of intracellular biothiols by dual-emission channels.

Development of Controllable Hetero-Pauson-Khand Polymerization to Functional Stimuli-Responsive Poly(γ-lactam)s.

Polymers containing lactam structures play a crucial role in both natural biological systems and human life, and their synthesis, functions and applications are of utmost importance for biomimetics and the creation of new materials. In this study, we developed an efficient heterogeneous Pauson-Khand polymerization (h-PKP) method for the controlled synthesis of main-chain poly(γ-lactam)s containing α, β-unsaturated γ-lactam functionalities using readily available internal alkynes and imines. The molecular weights of the resulting poly(N-Ts/γ-lactam)s can be precisely controlled by adjusting the ratio of phenyl formate and nickel. These polymers exhibit high solid-state luminescence and demonstrate rapid and sensitive dual responsiveness to light and acid stimuli. They further demonstrate strong reactive oxygen species (ROS) generation capability. The unique dual-emission peaks observed in poly(N-H/γ-lactam)s obtained through post-treatment under acidic conditions demonstrate a mechanism of aggregation-induced intermolecular excited-state proton transfer specific to lactam structures. The efficient one-pot synthetic method for poly(γ-lactam) provides a novel strategy for constructing polymers with γ-lactam structures in the main chain and the simple and efficient post-modification method offer a versatile toolbox for functionalizing poly(γ-lactam)s to expand their potential applications.