Reversible Interactions Research Articles

Facile Preparation of Polymerizable Deep Eutectic Solvents Under Mild Conditions for Multisensory Ionic Skins

AbstractPolymerizable deep eutectic solvents (PDESs) have emerged as promising building blocks for next‐generation eutectic gels, offering new opportunities for the development of advanced electronic devices. Traditional PDES fabrication typically involves heating and extended processing time. In this study, a facile method where a solid‐solid mixture of lithium bis(trifluoromethane) sulfonimide (LiTFSI) and acrylamide (AAm) rapidly forms a PDES at room temperature, significantly simplifying the ionogel preparation is presented. By combining this PDES with another system, comprising 3‐[dimethyl‐[2‐(2‐methylprop‐2‐enoyloxy)ethyl]azaniumyl]propane‐1‐sulfonate (SBMA) and ethylene glycol (EG), an eutectic gel is successfully fabricated with exceptional mechanical and conductive properties. This gel exhibits a fracture stress of 0.8 MPa, fracture energy of 3.7 kJ m−2, adhesion strength of 60 kPa, transmittance over 90%, high conductivity (0.113 S m−1), and an outstanding temperature tolerance ranged from ‐50 to 50 °C. Notably, the absence of chemical crosslinkers and the presence of reversible interactions such as hydrogen bonding and ion‐dipole electrostatic forces impart excellent self‐healing capabilities. These combined features position the gel a promising candidate for multisensory ionic skins, capable of detecting pressure, temperature, humidity, and sweat. This work pioneers the rapid, mild‐condition synthesis of PDESs, paving the way for new techniques in ionic skin development.

Discovery of Chalcone Derivatives as Bifunctional Molecules with Anti-SARS-CoV-2 and Anti-inflammatory Activities.

Danshensu extracted with traditional Chinese medicine Salvia miltiorrhiza has a wide range of bioactivities. Danshensu containing a catechol moiety has a moderate inhibitory effect on SARS-CoV-2 3CLpro (IC50 = 2.2 μM) by a reversible covalent interaction and exhibits good anti-inflammatory activity. To enhance the inhibitory activity, we introduced Michael receptors into the side chain of danshensu as a possible covalent warhead and blocked the covalent binding sites of catechol moiety to yield chalcone derivatives. The resulting chalcone derivatives, A4 and A7, were found to inhibit SARS-CoV-2 3CLpro in vitro with IC50 values of 83.2 and 261.3 nM, respectively. Furthermore, A4 and A7 inhibit viral replication in the SARS-CoV-2 replicon system with EC50 values of 19.9 and 11.7 μM, respectively. Time-dependent inhibition experiment and mass spectrometry show that A4 acted as a noncovalent mixed inhibitor, while A7 likely binds covalently at Cys145. The interaction mechanism between SARS-CoV-2 3CLpro and A4 or A7 was characterized by molecular docking studies. Additionally, both A4 and A7 demonstrated potent anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. These promising results suggest that chalcone derivatives A4 and A7 can serve as bifunctional molecules with both antivirus and anti-inflammatory properties.

Extremely Ultrahigh Stretchable Starch‐Based Hydrogels with Continuous Hydrogen Bonding

AbstractNatural polysaccharides‐based hydrogels have drawn extensive attention yet have been plagued by less desirable stretchability due to their inherent nature. Here, ultra‐stretchable starch‐based hydrogels (amylopectin/polyacrylamide, AAM) are developed by constructing reversible intramolecular physical interactions. This strategy endows the hydrogel with exceedingly ultrahigh deformation due to a continuous hydrogen bonding network. It can be stretched from less than 0.5 to >300 cm without breakage that the elongation exceeds 600 times the original length. The elongation collected by the universal testing machine reaches up to 36 000% without breakage outperforming previous reports and demonstrating extraordinary stretchability. Furthermore, an interwoven structure of hydrogen bonding interaction and trace covalent bonds make the stress of hydrogel reach 0.28 MPa, accompanied by an ultra‐high strain of 22 500% and significant toughness (47 MJ·m−3). The hydrogel displays high transparency (≈93%), low‐temperature resistance, moisturizing property, and extraordinary interfacial adhesion property. Intriguingly, the aqueous precursor can act as inks to prepare various forms of hydrogel within minutes through the facile writing or drawing method. This hydrogel verifies strong potential in both fields of human motion sensor (After long‐term or low‐temperature conditions) and energy storage. This study will facilitate the progress of ultra‐stretchable or multifunctional hydrogels.

Toughening Vitrimers Based on Dioxaborolane Metathesis through Introducing a Reversible Secondary Interaction

Toughening Vitrimers Based on Dioxaborolane Metathesis through Introducing a Reversible Secondary Interaction

Highly Elastic, Fatigue-Resistant, and Antifreezing MXene Functionalized Organohydrogels as Flexible Pressure Sensors for Human Motion Monitoring.

Conductive organohydrogels-based flexible pressure sensors have gained considerable attention in health monitoring, artificial skin, and human-computer interaction due to their excellent biocompatibility, wearability, and versatility. However, hydrogels' unsatisfactory mechanical and unstable electrical properties hinder their comprehensive application. Herein, an elastic, fatigue-resistant, and antifreezing poly(vinyl alcohol) (PVA)/lipoic acid (LA) organohydrogel with a double-network structure and reversible cross-linking interactions has been designed, and MXene as a conductive filler is functionalized into organohydrogel to further enhance the diverse sensing performance of flexible pressure sensors. The as-fabricated MXene-based PVA/LA organohydrogels (PLBM) exhibit stable fatigue resistance for over 450 cycles under 40% compressive strain, excellent elasticity, antifreezing properties (<-20 °C), and degradability. Furthermore, the pressure sensors based on the PLBM organohydrogels show a fast response time (62 ms), high sensitivity (S = 0.0402 kPa-1), and excellent stability (over 1000 cycles). The exceptional performance enables the sensors to monitor human movements, such as joint flexion and throat swallowing. Moreover, the sensors integrating with the one-dimensional convolutional neural networks and the long-short-term memory networks deep learning algorithms have been developed to recognize letters with a 93.75% accuracy, representing enormous potential in monitoring human motion and human-computer interaction.

Electrochemically Switchable Sulfurized Polyacrylonitrile for Controllable Recovery of Copper in Wastewater Based on Reversible Adsorption/Desorption Regulation.

Within the context of circular economy and industrial ecology, adsorption offers an effective manner for recycling resources from wastewater, but controllable desorption remains a challenge. Inspired by metal-thiol binding and reversible thiol-disulfide redox transformation in biological systems, this study reports the development of a reversible adsorption/desorption (RAD) system for controllable recovery of copper based on electrochemically switchable sulfurized polyacrylonitrile (SPAN). Density functional theory calculations offered theoretical prediction for the formation of S-Cu bonds and reversible weak interaction between S-S bonds and Cu2+. The SPAN anchored onto titanium suboxide ceramic foam (SPAN@TiSO) could regulate Cu2+ adsorption/desorption stimulated by the electrode potential, indicated by the adsorption capacity of 243.3 mg g-1 (30 min) at 0.2 V vs SHE and a desorption efficiency of 98.4% (5 min) at 0.8 V vs SHE. Electrochemical analysis revealed that the reversible redox transformation of S-S/-S- groups in SPAN was responsible for selective adsorption and rapid desorption in response to the electrode potential. This study provides a proof-of-concept demonstration of an electrochemically switchable polymer to build up a reversible RAD system for controllable recovery of heavy metals in wastewater, making value-added resource recovery more efficient, more intelligent, and more sustainable.

Elimination of mutagenic contaminants from water using cellulose bearing ferrous-phthalocyanine

BackgroundWe previously investigated methods for separating mutagenic contaminants from aqueous solutions using cellulose-bearing covalently bound trisulfo-Cu-phthalocyanine (blue cotton and blue rayon). Mutagenic contaminants with three or more fused aromatic rings in their structures were adsorbed onto blue cotton and rayon. Since Cu-phthalocyanine is considered an unsuitable absorption ligand for byproducts of water chlorination, such as 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (Mutagen X or MX), we investigated the development of a new material for the elimination of MX from aqueous solvents.ResultsWe selected green cellulose powder bearing ferrous phthalocyanine (FePh), hereafter referred to as green cellulose or GP, as the candidate material. GP is composed of cationized cellulose (white cellulose, WP) and FePh tetracarboxylic acid. The mutagenicity of MX dissolved in buffer or dimethyl sulfoxide (DMSO) solution significantly decreased after treatment with GP. The effects of GP on the elimination of MX from the solvent were very close to being expired after 70 cycles of repeated adsorption of the same GP, and the capacity of GP for MX removal was estimated to be exhausted after 120 cycles of repeated adsorption based on the extrapolation of the obtained result; thus, the interacting ligands on GP may be saturated after complete MX adsorption. The mutagenicity of MX dissolved in aqueous buffer significantly decreased after treatment at pH7.4 but not at pH 4.0. Since MX is dissociated to be the anionic form at pH 6 or higher, the negative charge of MX in the buffer at pH 7.4 may interact with the positive charge of ferrous ions in GP to create a linkage between MX and GP. After GP adsorbed MX, mutagenicity was extracted with water or acetonitrile and recovered in the eluent. Thus, the reversible interaction between MX and FePh may have caused adsorption of MX onto GP.ConclusionGP could be used as a new eliminator and recovery agent for MX in chlorinated drinking water. Developing new materials for the removal and recovery of agents for the detection of mutagenic contaminant-related chlorination in water is beneficial for environmental health.

Exploring the Interaction of Human α-Synuclein with Polyethylene Nanoplastics: Insights from Computational Modeling and Experimental Corroboration.

Plastics, particularly microplastics (MPs) and nanoplastics (NP), have become major environmental and health concerns due to their high chemical stability. The highly hydrophobic plastics enter living organisms through reversible interactions with biomolecules, forming biocoronas. Following recent reports on plastics breaching the blood-brain barrier, the binding behavior of human α-synuclein (hαSn) with polyethylene-based (PE) plastics was evaluated by using molecular dynamics simulations and experimental methods. The results provided three important findings: (i) hαSn transitions from an open helical to a compact conformation, enhancing intramolecular interactions, (ii) nonoxidized PE NPs (NPnonox) rapidly adsorb hαSn, as supported by experimental data from dynamic light scattering and adsorption isotherms, altering its structure, and (iii) the oxidized NP (NPox) failed to capture hαSn. These interactions were dominated by the N-terminal domain of hαSn, with major contributions from hydrophobic amino acids. These findings raise concerns about the potential pharmacological effects of NP-protein interactions on human health.

Performance of orange peels crosslinked β-cyclodextrin (OP-β-CD) to uptake lanthanum from water: Conventional adsorption studies and ultrasound-assisted desorption

Even though adsorption has been widely employed to recover rare earth elements such as lanthanum, desorption remains challenging since selectivity is often linked to strong adsorption forces. Herein we propose the grafting between orange peel (OP) wastes with beta-cyclodextrins (β-CD) for producing a highly reusable and stable adsorbent that allows the easy recovery of lanthanum in repeated cyclic runs. The morphological analysis confirmed that the OP-β-CD adsorbent was successfully functionalized with –OH groups, with β-CD grafting via citric acid expanding and stabilizing its structure. The pseudo-first-order model better represented the kinetics of lanthanum adsorption, while the isothermal behavior was better represented by the Langmuir model (qmax=95.79mgg−1), as shown by the thermodynamic analysis, which confirmed that the process was endothermic and spontaneous. The mechanism behind the efficiency of adsorption-desorption of lanthanum by OP-β-CD adsorbent was concluded to rely on: i) electrostatic and reversible interactions and ii) a driving force that increased as the amount of lanthanum increased in solution, leading to the formation of a monolayer. Around 95 % of lanthanum was desorbed using an ultrasound-assisted technique with citric acid, maintaining stable adsorption capacity for 5 cycles. In real matrices containing other rare earth elements and high calcium concentrations the removal exceeded 80 %. Thus, OP-β-CD's remarkable stability during desorption underscores its potential as a highly effective and sustainable solution for rare earth element recovery and removal.

Rational Design of Regenerable Amino-Functionalized Fluorescent Covalent Organic Framework for the Exclusive Detection of Mercury(II).

Goal-oriented development of novel covalent organic frameworks (COFs) to construct a sensing platform for highly toxic mercury (II, Hg2+) is of tremendous significance. Recently, numerous COFs with sulfur-based ligands were developed for Hg2+ monitoring; however, strong binding of Hg2+ by sulfur makes their regeneration very tough. Herein, we designed and developed an amino-functionalized fluorescent COF (COF-NH2) through facile postmodification for Hg2+ detection in which the π-conjugation skeleton is the signal reader and the nitrogen-based side is the highly selective Hg2+ receptor. More importantly, this nitrogen-based receptor permits the reversible binding of Hg2+. As a sensing platform, the outstanding performance of COF-NH2 for Hg2+ detection was reached with respect to high sensitivity with an ultralow detection of 15.3 nM, real-time response with rapid signal change of 10 s, and facile visualization with significant fluorescence color change. Expectedly, COF-NH2 obtained facile recycling which still shows excellent response performance toward Hg2+ after six cycles based on the reversible interaction between amino groups and Hg2+. Our work not only shows an attractive foreground of fluorescent COF for Hg2+ detection but also emphasizes the easy construction of novel COF materials via the rational introduction of metal ligands for the recognition of other metal ions.

Activation of muscle amine functional groups using eutectic mixture to enhance tissue adhesiveness of injectable, conductive and therapeutic granular hydrogel for diabetic ulcer regeneration

Herein, Polydopamine-modified microgels and microgels incorporated with superficial epoxy groups were synthesized and applied as precursors for the fabrication of four granular hydrogels. To enhance the tissue adhesiveness, a ternary deep eutectic solvent was synthesized to activate the muscle amine functional groups facilitating the formation of robust NC bonds at ambient conditions. At a certain shear rate of 10 s−1, hydrogel DMG displayed a viscosity of 9×103 Pa/s, representing the highest complex viscosity among the tested hydrogels primarily driven by quinone groups in PDA which enhanced reversible interactions, thereby increasing particle cohesion. Moreover, the intersection point escalating from about 4×103 to approximately 9×104 as the concentration of DMG increased from 0 % (for MG) to 70% (7D3MG) by weight. There was a decrease in adhesion strength from 0.45 ± 0.08 N in MG to 0.39 ± 0.16 N, 0.35± 0.18 N, and 0.33 ± 0.15 N for 3D7MG, 7D3MG, and DMG respectively, suggesting that MG was capable of forming numerous covalent bonds, thereby enhancing its adhesion to the substrate. The type of eutectic mixture affected the electrical conductivity and a very important point was the changes in resistance value with time. For MG catalyzed by [DES]AZG, the resistance increased only by 1.3 % (from 3.37 to 3.81 kΩ) at day 3 and 37.09 % (from 3.37 to 4.62 kΩ) at day 5. The 3D7MG hydrogel exhibited superior therapeutic efficacy toward diabetic wound regeneration. The proliferation index value for 3D7MG-[DES]AZG and 3D7MG-[DES]AG were calculated 42.3 % and 58.6 %, respectively, while the control group exhibited a lower value of 37.8 %.

Paper-Based Analytical Devices Based on Amino-MOFs (MIL-125, UiO-66, and MIL-101) as Platforms towards Fluorescence Biodetection Applications

In this study, we designed three promising platforms based on metal–organic frameworks (MOFs) to develop paper-based analytical devices (PADs) for biosensing applications. PADs have become increasingly popular in field sensing in recent years due to their portability, low cost, simplicity, efficiency, fast detection capability, excellent sensitivity, and selectivity. In addition, MOFs are excellent choices for developing highly sensitive and selective sensors due their versatility for functionalizing, structural stability, and capability to adsorb and desorb specific molecules by reversible interactions. These materials also offer the possibility to modify their structure and properties, making them highly versatile and adaptable to different environments and sensing needs. In this research, we synthesized and characterized three different amino-functionalized MOFs: UiO-66-NH2 (Zr), MIL-125-NH2 (Ti), and MIL-101-NH2 (Fe). These MOFs were used to fabricate PADs capable of sensitive and portable monitoring of alkaline phosphatase (ALP) enzyme activity by laser-induced fluorescence (LIF). Overall, amino-derivated MOF platforms demonstrate significant potential for integration into biosensor PADs, offering key properties that enhance their performance and applicability in analytical chemistry and diagnostics.

A sequential binding mechanism for 5′ splice site recognition and modulation for the human U1 snRNP

Splice site recognition is essential for defining the transcriptome. Drugs like risdiplam and branaplam change how human U1 snRNP recognizes particular 5′ splice sites (5′SS) and promote U1 snRNP binding and splicing at these locations. Despite the therapeutic potential of 5′SS modulators, the complexity of their interactions and snRNP substrates have precluded defining a mechanism for 5′SS modulation. We have determined a sequential binding mechanism for modulation of −1A bulged 5′SS by branaplam using a combination of ensemble kinetic measurements and colocalization single molecule spectroscopy (CoSMoS). Our mechanism establishes that U1-C protein binds reversibly to U1 snRNP, and branaplam binds to the U1 snRNP/U1-C complex only after it has engaged with a −1A bulged 5′SS. Obligate orders of binding and unbinding explain how reversible branaplam interactions cause formation of long-lived U1 snRNP/5′SS complexes. Branaplam targets a ribonucleoprotein, not only an RNA duplex, and its action depends on fundamental properties of 5′SS recognition.

Analysis of interactions between pharmaceuticals and humic acid: Characterization using entrapment and high-performance affinity microcolumns

The presence of pharmaceuticals as microcontaminants in the environment has become of particular concern given the growing increase in water reuse and recycling to promote global sustainability of this resource. Pharmaceuticals can often undergo reversible interactions with soluble dissolved organic material such as humic acid, which may be an important factor in determining the bioavailability and effects of these compounds in the environment. In this study, high-performance affinity microcolumns containing non-covalently entrapped and immobilized humic acid are used to examine the binding strength and interactions of this agent for tetracycline, carbamazepine, ciprofloxacin, and norfloxacin, all common pharmaceutical microcontaminants known to bind humic acid. The binding constants, as measured with Aldrich humic acid, have good agreement with values reported in the literature. In addition, the effects of temperature, ionic strength, and pH on these interactions are examined with the humic acid microcolumns. This technique makes it possible to determine the relative importance of electrostatic interactions vs non-polar interactions or hydrogen bonding on these binding processes. This study illustrates how affinity microcolumns can be used to screen and uniformly quantify binding by pharmaceuticals with humic acid, as well as to study the mechanisms of these interactions, with this information often being acquired in minutes and with small amounts of binding agent (∼10 mg per microcolumn, which could be used over 200–300 experiments). Use of entrapment and affinity microcolumns can support similar research for a wide range of other microcontaminants with humic acid or alternative binding agents found in water and the environment.

Structural modification and functional improvement of lactoferrin through non-covalent and covalent binding to coffee polyphenol

Studies have suggested that milk may enhance or neutralize the bioavailability of coffee polyphenols, possibly due to reversible and irreversible interactions between coffee polyphenols and milk proteins. The effects of non-covalent and covalent binding of lactoferrin (BLF) to caffeic acid (CAA) on protein structure and function were investigated. SDS-PAGE analysis confirmed the covalent interaction between BLF and CAA. Multispectral experiments characterized the BLF-CAA complexes and conjugates, revealing alterations in the tertiary structure of the proteins in the BLF-CAA conjugates. Molecular docking and kinetics results demonstrated that hydrogen bonding, electrostatic interaction, and hydrophobic forces were the primary internal forces between CAA and BLF. When combined with CAA, the covalent conjugates exhibited superior functional properties including solubility, oxidation resistance, thermal stability, emulsification and foamability, bioaccessibility, and antimicrobial properties. This study offers a theoretical foundation and technical benchmark for the preparation of protein-based delivery vectors with synergistic effects.

OptoAssay-Light-controlled dynamic bioassay using optogenetic switches.

Circumventing the limitations of current bioassays, we introduce a light-controlled assay, OptoAssay, toward wash- and pump-free point-of-care diagnostics. Extending the capabilities of standard bioassays with light-dependent and reversible interaction of optogenetic switches, OptoAssays enable a bidirectional movement of assay components, only by changing the wavelength of light. Demonstrating exceptional versatility, the OptoAssay showcases its efficacy on various substrates, delivering a dynamic bioassay format. The applicability of the OptoAssay is successfully demonstrated by the calibration of a competitive model assay, resulting in a superior limit of detection of 8 pg ml-1, which is beyond those of conventional ELISA tests. In the future, combined with smartphones, OptoAssays could obviate the need for external flow control systems such as pumps or valves and signal readout devices, enabling on-site analysis in resource-limited settings.

Aminated lignin and phytic acid-assisted polyacrylic acid hydrogel sensors with enhanced mechanical properties and strong adhesion

Excellent comprehensive performance of hydrogels can be achieved by synergistically combining multiple interaction mechanisms. In this study, a series of hydrogels with rapid gelation and excellent adhesive, mechanical, self-healing, and conductive properties, driven by covalent bonds and multiple reversible interactions, were constructed by mixing acrylic acid (AA), aminated alkaline lignin (AAL), phytic acid (PA), and Fe3+. The rigid skeletons of polyacrylic acid (PAA) and AAL, as well as the metal coordination bonds formed between them and Fe3+, enhance the mechanical properties of the samples. The samples exhibit excellent tensile strength and compressive strength, reaching 73.7 kPa and 4.6 MPa (under a compressive strain of 80 %), respectively, with a tensile strain of 1142 % under the same condition. Adding PA enhances the compliance and adhesion (148.2 kPa for porcine skin) of the gel and endowed it with good flame retardancy. Additionally, the sample maintained its good mechanical properties and conductivity even after five cutting-healing cycles. Good durability, robust adhesion, and high electrical conductivity of the sample render it a promising strain sensor for electronic devices. This work provides a design strategy for preparing hydrogels with superior adhesion and good comprehensive performance.

Multifunctional double network hydrogel with multi-directional actuation and high-precision sensing

Conductive hydrogels have gained great attention for applications in flexible electronics, electronic skins, and as human-machine interfaces. However, poor environmental tolerance of traditional hydrogels and defects in hydrogel actuator make them unfit for use in certain environments. Herein, a small natural molecule, proline (ZP), was introduced into the PAA/CS dual network system to prepare multifunctional hydrogel materials with high concentration of physically crosslinked metal coordination points. The elongation at break and mechanical strength of the hydrogel with optimized structure were 1277 % and 202 kPa, respectively. The effect of ZP on the destruction of hydrogen bonds of free water in the hydrogel provided the hydrogel with excellent temperature resistance. Multiple reversible interactions endowed the PAA/CS/Al0.5/ZP8 hydrogel with excellent self-healing properties at room temperature and even at −40 ℃. The PAA/CS/Al0.5/ZP8 hydrogel sensor with excellent comprehensive performance could be applied for the monitoring of a variety of human motions, small shape changes of flexible objects, and detection of vibrations in rigid pipes. The interactions between Fe3+, ascorbic acid, and -COOH groups on the hydrogel surface were used to record information and erase it repeatedly at low temperature and showed excellent shape memory. Based on the self-healing property, the hydrogel with gradients of swelling rates and water loss rates was assembled into a double-layer actuator, which could complete the actuation process in opposite directions in air and also underwater. This work provides a new idea for the design of soft robots and intelligent switches.

Developing flame retardant, smoke suppression and self-healing polyvinyl alcohol composites by dynamic reversible cross-linked chitosan-based macromolecule

With the increasing threat of white pollution to the public health and ecosystem, functional materials driven by green and sustainable biological macromolecule are attracting considerable attention. Inspired by the double-helix structure of DNA, a P–B–N ternary synergistic chitosan-based macromolecule (PBCS) was constructed to prepare flame retardant, smoke suppression and self-healing polyvinyl alcohol composite (PVA@PBCS) via dynamic reversible interactions. The limiting oxygen index value of PVA@PBCS increased from 19.6 % to 28.7 %, whereas the peak heat release rate and total heat release decreased by 47.04 % and 43.37 %, respectively. Besides, the peak smoke production rate and total smoke production of PVA@PBCS also decreased by 45.31 % and 54.98 %. With the presence of borate ester-based covalent and multiple hydrogen bonds, the tensile strength and elongation at break of PVA@PBCS increased by 19.50 % and 16.85 % compared to the control sample, and the healing efficiency for tensile strength and elongation at break was as high as 93.86 % and 90.57 %, respectively. This work developed an eco-friendly and effective scenario for fabricating flame retardant and smoke suppression PVA materials, stimulating the substantial potential of chitosan-based biomacromolecule and dynamic reversible cross-linked tactics in self-healing field.

Polymer hydrogel electronics with adhesive, self-healing, and anti-ultraviolet capabilities for machine learning-promoted electrophysiological detection

While adjustable mechanical properties, diverse biochemical features, and good ionic conductivity enabled by molecular engineering, polymer hydrogels as ionic skins (i-skins) are still limited by multiple challenges in the practical human health monitoring and health diagnosis, such as undesirable ductility and contact adhesion, poor functionality, and insufficient sensing ability. In view of this, the strategy of multiple dynamic interactions was proposed, and a mussel characteristic double-network polymer composite hydrogel (PG-BT2) with tannic acid and borax as dynamic media was reasonably designed. Due to the dynamic reversible interactions from the crosslinked network combined with special functional groups, the obtained PG-BT2 hydrogel attains remarkable stretchability with >1200 % elongation and good toughness of 268.6 kJ/m−3, and also possesses favorable versatility (e.g., self-healing time <2 s, adhesion strength of 4.62 kPa to pigskin, and UV transmittance of 15.3 % at 365 nm). Additionally, the i-skin derived from the PG-BT2 hydrogel exhibits excellent sensing properties, including a low interface contact resistance of 8.3 kΩ at 1 kHz, fast response/recovery time of 0.657 s/0.348 s, and a wide sensing range of 0–1100 % strain. By combining the hydrogel-based i-skin patch with the wireless circuit connected to a Bluetooth module, the constructed sensor system is capable of accurately monitoring micro-expressions and multi-joint movements. The portable system is also demonstrated to capture high-fidelity signals of electrocardiograms available for training artificial intelligence, achieving differentiation and recognition of blood pressure status, which will greatly benefit health management and intelligent medicine.