Collagen fiber-reinforced, tough and adaptive conductive organohydrogel e-skin for multimodal sensing applications.

Conductive hydrogels (CHs) with high sensitivity and multifunctional property are considered as excellent materials for wearable devices and flexible electronics. Surface synapses and internal multilayered structures are key factors for highly sensitive pressure sensors. Nevertheless, current CHs lack environmental adaptability, multifunctional perception, and instrument portability, which seriously hinders their application as sensors. Here, waste collagen fibers (buffing dust of leather), polyvinyl alcohol (PVA) and gelatin (Gel) were used as the basic framework of the hydrogel, loaded with a conductive material (silver nanoparticles (BD-CQDs@AgNPs)) and an anti-freezing moisturizer (glycerol (Gly)), resulting in a multifunctional conductive organohydrogel (BPGC-Gly). As a temperature and humidity sensor, it demonstrated an excellent temperature response range (-20-60 °C) and was capable of rapid response (2.4 s) and recovery (1.6 s) to human breathing. As a strain/pressure sensor, it allowed real-time monitoring of human movement and had a high low-pressure sensitivity (S = 4.26 kPa-1, 0-12.5 kPa). Interestingly, BPGC-Gly could also be used as a portable bioelectrode or the acquisition, monitoring and analysis of EMG/ECG signals. In this work, BPGC-Gly was assembled with wireless transmission to achieve multimodal heath detection, which opens new avenues for multi-responsive CHs, comprehensive human health monitoring and next-generation wearable electronic skin (e-skin).

CQDs-Cross-Linked Conductive Collagen/PAA-Based Nanocomposite Organohydrogel Coupling Flexibility with Multifunctionality for Dual-Modal Sensing of Human Motions.

Conductive hydrogels are ideal materials for intelligent medical devices, human-machine interfaces, and flexible bioelectrodes due to their adjustable mechanical properties and electrical responsiveness, whereas it is still a great challenge to achieve the integration of excellent flexibility and biocompatibility into one hydrogel sensor while also incorporating self-healing, self-adhesion, environmental tolerance, and antimicrobial properties. Here, a nanocomposite conductive organohydrogel was constructed by using collagen (Col), alginate-derived carbon quantum dots (OSA-CQDs), poly(acrylic acid) (PAA), ethylene glycol reduced AgNPs, and Fe3+ ions. Depending on OSA-CQDs with multiple chemical binding sites and high specific surface area as cross-linkers, while coupling highly biologically active Col chains and PAA chains are serving as an energy dissipation module, the resulting organohydrogel exhibited excellent flexibility (795% of strain, 193 kPa of strength), high cell compatibility (>95% survival rate), self-healing efficiency (HE = 79.5%), antifreezing (-20 °C), moisturizing (>120 h), repeatable adhesion (strength >20 kPa, times >10), inhibitory activity against Escherichia coli and Staphylococcus aureus (9 and 21.5 cm2), conductivity, and strain sensitivity (σ = 1.34 S/m, gauge factor (GF) = 11.63). Based on the all-in-one integration of multifunction, the organohydrogel can collaboratively adapt to the multimode of strain sensing and electrophysiological sensing to realize wireless real-time monitoring of human activities and physiological health. Therefore, this work provides a new and common platform for the design and sensing of next-generation hydrogel-based smart wearable sensors.

Self-Healable, Adhesive, Anti-Drying, Freezing-Tolerant, and Transparent Conductive Organohydrogel as Flexible Strain Sensor, Triboelectric Nanogenerator, and Skin Barrier.

Conductive hydrogels have attracted tremendous interest in the construction of flexible strain sensors and triboelectric nanogenerators (TENGs) owing to their good stretchability and adjustable properties. Nevertheless, how to simultaneously achieve high transparency, self-healing, adhesion, antibacterial, anti-freezing, anti-drying, and biocompatibility properties through a simple method remains a challenge. Herein, a transparent, freezing-tolerant, and multifunctional organohydrogel (PAOAM-PDO) as electrode for strain sensors and TENGs was constructed through a free radical polymerization in the 1,3-propanediol (PDO)/water binary solvent system, in which oxide sodium alginate, aminated gelatin, acrylic acid, and AlCl3 were used as raw materials. The obtained PAOAM-PDO exhibited good transparency (>90%), self-healing, adhesiveness, antibacterial property, good conductivity (1.13 S/m), and long-term environmental stability. The introduction of PDO endowed PAOAM-PDO with freezing resistance with a low freezing point of -60 °C, and PAOAM-PDO could serve as a protective skin barrier to prevent frostbite at low temperature. PAOAM-PDO could be assembled as strain sensors to monitor heterogeneous human movements with high strain sensitivity (gauge factor of 7.05, strain = 233%). Meanwhile, PAOAM-PDO could be further fabricated as a TENG with a "sandwich" structure in single electrode mode. Moreover, the resulting TENG achieved electrical outputs with simple hand tapping and served as a self-powered device to light light-emitting diodes. This work displays a feasible strategy to build environment-tolerant and multifunctional organohydrogels, which possess potential applications in the wearable electronics and self-powered devices.

Collagen-Based Organohydrogel Strain Sensor with Self-Healing and Adhesive Properties for Detecting Human Motion.

Conductive hydrogels are ideal for flexible sensors, but it is still a challenge to produce such hydrogels with combined toughness, self-adhesion, self-healing, anti-freezing, moisturizing, and biocompatibility properties. Herein, inspired by natural skin, a highly stretchable, strain-sensitive, and multi-environmental stable collagen-based conductive organohydrogel was constructed by using collagen (Col), acrylic acid, dialdehyde carboxymethyl cellulose, 1,3-propylene glycol, and AlCl3. The resulting organohydrogel exhibited excellent tensile (strain >800%), repeatable adhesion (>10 times), self-healing [self-healing efficiency (SHE) ≈ 100%], anti-freezing (-60 °C), moisturizing (>20 d), and biocompatible properties. This organohydrogel also possessed good electrical conductivity (σ = 3.4 S/m) and strain-sensitive properties [GF (gauge factor) = 13.65 with the maximal strain of 400%]. Notably, the organohydrogel had a considerable low-temperature self-healing performance (SHE = 88% at -24 °C) and rapid underwater self-healing property (SHE = 92%, self-healing time <20 min). This type of strain sensor could not only accurately and continuously monitor the large-scale motions of the human body but also provide an accurate response to the human tiny motions. This work not only proposes a development strategy for a multifunctional conductive organohydrogel with multiple environmental stability but also provides potential research value for the construction of biomimetic electronic skin.

Chestnut-Tannin-Crosslinked, Antibacterial, Antifreezing, Conductive Organohydrogel as a Strain Sensor for Motion Monitoring, Flexible Keyboards, and Velocity Monitoring.

Flexible sensing devices (FSDs) fabricated using conductive hydrogels have attracted researchers' extensive enthusiasm in recent years due to their versatility. Considering the complexity of their application environments, the integration of various functional characteristics (e.g., excellent mechanical, antibacterial, and antifreezing properties) is an important guarantee for FSDs to stably perform their applications in different environments. Herein, we developed a multifunctional conductive polyvinyl alcohol (PVA) organohydrogel PVA-CT-Ag-Al-Gly (PCAAG) by using a green, natural, and cheap biomass, chestnut tannin (CT), as a crosslinking agent, nano-silver particles (AgNPs) as an antimicrobial agent, aluminum trichloride (AlCl3) as a conducting medium, and the mixed water-glycerol as the solvent system. In this organohydrogel system, CT acted not only as the reducing and stabilizing agent for the preparation of antibacterial AgNPs but also as the crosslinking agent owing to its strong multiple hydrogen bonding interactions with PVA, realizing its multifunctional application. The PCAAG organohydrogel possessed outstanding physical and mechanical properties (350.54% of the maximum fracture strain and 1.55 MPa of the maximum tensile strength), considerable bacteriostatic effects against both Escherichia coli and Staphylococcus aureus, and excellent freeze resistance (it could function normally at -20 °C). The motion-monitoring sensor based on the PCAAG organohydrogel exhibited excellent specificity recognition for both large-amplitude (e.g., elbow bending, wrist bending, finger bending, running and walking, etc.) and small-amplitude (frowning and swallowing) human movements. The flexible keyboard constructed by using the PCAAG organohydrogel could easily achieve the transformation between digital signals and electrical signals, and the signal output had both specificity and stability. The velocity-monitoring sensor fabricated by using the PCAAG organohydrogel could accurately measure the speed of the object movement (less than 3% of relative error). In short, the present PCAAG organohydrogel solves the problems of the single application environment and a few application scenarios of traditional conductive hydrogels and possesses remarkable application potential as a multifunctional FSD in many fields such as artificial intelligence, sport management, soft robots, and human-computer interface.

[Analysis of clinical phenotype and genetic variant in a Chinese pedigree affected with cleidocranial dysplasia].

OBJECTIVE: To analyze the clinical features and pathogenic variant in a Chinese pedigree affected with cleidocranial dysplasia (CCD). METHODS: Clinical data of 8 patients from the pedigree was collected, including physical examination and X-ray images of head, face, spine, limbs, and mouth. Peripheral blood samples were collected from 6 affected members for the extraction of genomic DNA. The proband and other 3 patients were subjected to trio-whole exome sequencing. Candidate variant was verified by Sanger sequencing of the other 2 affected members from the pedigree. RESULTS: This pedigree has included 22 members (8 affected) from four generations. Genetic testing revealed that the proband has harbored a novel pathogenic variant of the RUNX2 gene [NM_001024630: c.1268_1277del (p.P425Afs*56)], which was inherited from her mother and carried by all affected members in the pedigree. The same variant was not detected among the unaffected members, suggesting co-segregation with the phenotype. CONCLUSION: The c.1268_1277del (p.P425Afs*56) variant of the RUNX2 gene probably underlay the pathogenesis of CCD in this pedigree. Genetic testing has facilitated the definite diagnosis and enabled prenatal diagnosis.

Highly Sensitive and Robust Polysaccharide-Based Composite Hydrogel Sensor Integrated with Underwater Repeatable Self-Adhesion and Rapid Self-Healing for Human Motion Detection.

Tough, biocompatible, and conductive hydrogel-based strain sensors are attractive in the fields of human motion detection and wearable electronics, whereas it is still a great challenge to simultaneously integrate underwater adhesion and self-healing properties into one hydrogel sensor. Here, a highly stretchable, sensitive, and multifunctional polysaccharide-based dual-network hydrogel sensor was constructed using dialdehyde carboxymethyl cellulose (DCMC), chitosan (CS), poly(acrylic acid) (PAA), and aluminum ions (Al3+). The obtained DCMC/CS/PAA (DCP) composite hydrogels exhibit robust mechanical strength and good adhesive and self-healing properties, due to the reversible dynamic chemical bonds and physical interactions such as Schiff base bonds and metal coordination. The conductivity of hydrogel is 2.6 S/m, and the sensitivity (gauge factor (GF)) is up to 15.56. Notably, the DCP hydrogel shows excellent underwater repeatable adhesion to animal tissues and good self-healing properties in water (self-healing rate > 90%, self-healing time < 10 min). The DCP hydrogel strain sensor can sensitively monitor human motion including finger bending, smiling, and wrist pulse, and it can steadily detect human movement underwater. This work is expected to provide a new strategy for the design of high-performance intelligent sensors, particularly for applications in wet and underwater environments.

Rapid self-healing and self-adhesive chitosan-based hydrogels by host-guest interaction and dynamic covalent bond as flexible sensor.

A sensor used to monitor tissue deformation requires good flexibility, stretchability, self-adhesion, cyto-compatibility, and antibacterial property. Here, we prepared hydrogel sensor based on O-carboxymethyl chitosan (O-CMCS) and poly(vinyl alcohol) (PVA) for monitoring human and organ motions. Based on the host-guest complexing of poly(ß-cyclodextrin) with diamantane, a cross-linker containing multiple aldehyde groups was prepared for cross-linking with O-CMCS through Schiff base linkages. Borax was used as the second cross-linker to cross-link PVA through dynamic borate ester bonds. Carbon nanotubes (CNTs) were added into the hydrogels to improve their electrical conductivity and mechanical properties. The obtained hydrogel exhibited rapid self-healing ability with healing efficiency as high as 97%-103% (in 15 s), good adhesion to human skin and wet organ, good antibacterial property, cyto-compatibility, and stretchability. Furthermore, the hydrogel sensor can monitor the respiratory movement of porcine lungs and the beating of rat hearts.

ROMP Synthesis of Side-Chain Ferrocene-Containing Polyelectrolyte and Its Redox-Responsive Hydrogels Showing Dramatically Improved Swelling with ß-Cyclodextrin.

A new side-chain ferrocene (Fc)-containing polyelectrolyte has been synthesized by controlled ring-opening metathesis polymerization of a water-soluble Fc-containing norbornene-based quaternary ammonium salt, as well as the corresponding covalently cross-linked polyelectrolyte hydrogel. In order to provide Fc-containing supramolecular polyelectrolyte hydrogels whose swelling property is largely improved by host-guest interaction, a covalently cross-linked polyelectrolyte hydrogel is soaked into the ß-CD aqueous solution to form ß-CD@Fc supramolecular polyelectrolyte hydrogel, or alternatively the quaternary ammonium salt supramolecular monomer is first formed, then copolymerized with a crosslinking agent to fabricate the supramolecular hydrogel with better water absorption ability. All the Fc-containing hydrogels exhibited good redox-responsiveness with swelling-shrinking behaviors by chemically reversibly adjusting the disassembly/assembly of ß-CD@Fc inclusion complexes. This is the first example of side-chain Fc-containing polycationic supramolecular hydrogels possessing swelling-shrinking properties based on the splitting/combining of ß-CD and Fc units, and potential applications are expected as controlled drug delivery and actuators.

Multifunctional Self-Healing Dual Network Hydrogels Constructed via Host-Guest Interaction and Dynamic Covalent Bond as Wearable Strain Sensors for Monitoring Human and Organ Motions.

Hydrogel-based flexible strain sensors have shown great potential in body movement tracking, early disease diagnosis, noninvasive treatment, electronic skins, and soft robotics. The good self-healing, biocompatible, sensitive and stretchable properties are the focus of hydrogel-based flexible strain sensors. Dual network (DN) hydrogels are hopeful to fabricate self-healing hydrogels with the above properties. Here, multifunctional DN hydrogels are prepared via a combination of host-guest interaction of ß-cyclodextrin and ferrocene with dynamic borate ester bonds of poly(vinyl alcohol) and borax. Carbon nanotubes are used to endow the DN hydrogels with good conductivity. The obtained DN composite hydrogels possess good biocompatibility, stretchability (436%), fracture strength (41.0 KPa), self-healing property (healing efficiency of 95%), and high tensile strain sensitivity (gauge factor of 5.9). The DN composite hydrogels are used as flexible strain sensors to detect different human motions. After cutting, the healed hydrogels also can monitor human motions and have good stability. In addition, the hydrogel sensors may track the respiratory movement of a pig lung in vitro. This work exhibits new ideas and approaches to develop multifunctional self-healing hydrogels for constructing flexible strain sensors.

A Multifunctional, Self-Healing, Self-Adhesive, and Conductive Sodium Alginate/Poly(vinyl alcohol) Composite Hydrogel as a Flexible Strain Sensor.

Hydrogel-based wearable devices have attracted tremendous interest due to their potential applications in electronic skins, soft robotics, and sensors. However, it is still a challenge for hydrogel-based wearable devices to be integrated with high conductivity, a self-healing ability, remoldability, self-adhesiveness, good mechanical strength and high stretchability, good biocompatibility, and stimulus-responsiveness. Herein, multifunctional conductive composite hydrogels were fabricated by a simple one-pot method based on poly(vinyl alcohol) (PVA), sodium alginate (SA), and tannic acid (TA) using borax as a cross-linker. The composite hydrogel network was built by borate ester bonds and hydrogen bonds. The obtained hydrogel exhibited pH- and sugar-responsiveness, high stretchability (780% strain), and fast self-healing performance with healing efficiency (HE) as high as 93.56% without any external stimulus. Additionally, the hydrogel displayed considerable conductive behavior and stable changes of resistance with high sensitivity (gauge factor (GF) = 15.98 at a strain of 780%). The hydrogel was further applied as a strain sensor for monitoring large and tiny human motions with durable stability. Significantly, the healed hydrogel also showed good sensing behavior. This work broadens the avenue for the design and preparation of biocompatible polymer-based hydrogels to promote the application of hydrogel sensors with comfortable wearing feel and high sensitivity.

Synthesis, conjugating capacity and biocompatibility evaluation of a novel amphiphilic polynorbornene.

Polynorbornenes, prepared by the 'living' and 'controlled' ring-opening metathesis polymerization (ROMP) method, have emerged as a stimuli-sensitive new class of polymer carriers. Herein, we reported a novel amphiphilic diblock polynorbornene, PNCHO-b-PNTEG, containing active benzaldehyde units, which exhibited good conjugating capacity to amino-containing molecules (e.g., doxorubicin (DOX)) via the pH-sensitive Schiff base linkage. The copolymer and its conjugate with DOX, DOX-PNCHO-b-PNTEG, were adequately analyzed by various techniques including 1H NMR, 13C NMR, gel permeation chromatography, etc. Especially, the formed conjugate of DOX-PNCHO-b-PNTEG could self-assemble into near-spherical micelles with the diameter of 81 ± 10 nm, and exhibit acid-triggered DOX release behavior, and the release rate could be adjusted by changing the environmental pH value. The excellent biological safety of PNCHO-b-PNTEG was further demonstrated by the results from both in vitro toxicity evaluation to murine fibroblast cells (L-929 cells) and in vivo evaluation of acute developmental toxicity and cell death in zebrafish embryos. Hence, the present polynorbornene-based PNCHO-b-PNTEG possesses great potential application as a biocompatible polymeric carrier and could be employed to fabricate various pH-sensitive conjugates.

Multiple applications of polymers containing electron-reservoir metal-sandwich complexes.

Ferrocene-containing polymers have been investigated for more than six decades, and more recently modern synthetic methods have allowed the fabrication of precise polymers that contain a variety of transition-metal complexes. Trends are now oriented towards applications, such as optics, energy conversion and storage, electrochemistry, magnetics, electric conductors and biomedicine. Metal-sandwich complexes such as those of ferrocene type and other related complexes that present redox-robust groups in polymers, i.e. that are isolable in both their oxidized and reduced forms, are of particular interest, because it is possible to address them using electronic or photonic redox stimuli for application. Our research groups have called such complexes Electron-Reservoirs and introduced them in the main chain or in the side chains of well-defined polymers. For instance, polymers with ferrocene in the main chain or in the side chain are oxidized to stable polycationic polyelectrolytes only if ferrocene is part of a biferrocene unit, because biferrocene oxidation leads to the biferrocenium cation that is stabilized by the mixed valency. Then a group of several redox-robust iron sandwich complexes were fabricated and incorporated in precise polymers including multi-block copolymers whose controlled synthesis and block incorporation was achieved for instance using ring-opening-metathesis polymerization. Applications of this family of Electron-Reservoir-containing polymers includes electrochemically induced derivatization of electrodes by decorating them with these polymers, molecular recognition and redox sensing, electrochromics with multiple colours, generation of gold and silver nanoparticles of various size by reduction of gold(iii) and silver(i) precursors and their use for nanocatalysis towards depollution and biomedicine.

Supramolecular redox-responsive substrate carrier activity of a ferrocenyl Janus device.

Supramolecular Janus compounds have recently attracted increasing attention owing to their dynamic reversible properties, distinct topological structures, and remarkable physicochemical characteristics, e.g., amphiphilicity, heterofunctionality, and high-density of terminal groups. Herein, a new redox-responsive supramolecular Janus device was designed and synthesized involving ß-cyclodextrin and 2-fold ferrocene host-guest interactions. The complex formation was analyzed via one-dimensional 1H NMR and two-dimensional Nuclear Overhauser Enhancement Spectroscopy. FeCl3 and ascorbic acid were used as oxidation and reduction triggers, respectively, to modulate the self-assembly behavior in water through complexation/dissociation of ß-cyclodextrin inclusion compounds resulting from redox-conversion of the ferrocenyl guest moieties. The redox-responsiveness of the obtained supramolecular micelles was studied via scanning electron microscopy and dynamic light scattering. Substrate-loading ability of the supramolecular micelles was confirmed with Rhodamine B, and the oxidation of ferrocenyl groups led to the release of the loaded cargos. The present work illustrates a valuable design example of supramolecular Janus systems using the host-guest complexation between ß-cyclodextrin and ferrocenyl structures. The present supramolecular micelle may be used as a promising molecular vehicle for application in the field of stimuli-responsive drug delivery.

Dendronized triazolyl-containing ferrocenyl polymers as stabilizers of gold nanoparticles for recyclable two-phase reduction of 4-nitrophenol.

A series of small-sized (about 2.0 nm) gold nanoparticles (AuNPs) with apparent lattice fringes are synthesized by NaBH4 reduction of HAuCl4 in the presence of stabilizing linear or dendronized 1,2,3-triazolyl-containing ferrocenyl polymers. These AuNPs show high catalytic activity for biphasic 4-nitrophenol (4-NP) reduction to 4-aminophenol (4-AP) by NaBH4. The lower generation G1 dendronized polymers (DPs) is a more efficient stabilizer for AuNP catalytic activity in the reduction of 4-NP than linear G0 polymers or bulky G2 DPs. The G1 DP-stabilized AuNPs are robust and easily recyclable, and the catalyst is recovered and reused at least twenty times with progressive smooth AuNP size increase along with some decrease of catalytic activity.

Study on the correlation between adipocyte fatty-acid binding protein, glucolipid metabolism, and pre-eclampsia.

AIM: We aimed to explore the relation between the level of adipocyte fatty-acid binding protein (A-FABP) in the gestational period and related indices of glucolipid metabolism, and the possible mechanisms of occurrence and development of pre-eclampsia. METHODS: Seventy-six pre-eclampsia patients were enrolled and divided into the mild pre-eclampsia (n = 42) and severe pre-eclampsia (n = 34) groups. Forty-eight healthy pregnant women were selected as a control group. The indices of all participants were examined, including serum A-FABP, fasting insulin (FINS), fasting blood glucose, total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL), and homeostatic model assessment insulin resistance (HOMA-IR) index was calculated. After the delivery of the placenta, the level of A-FABP in the placenta was detected by immunochemistry. Then, the correlation between serum A-FABP and indices of glucolipid metabolism and placental A-FABP were analyzed. RESULTS: Serum A-FABP, FINS, TG, TC, HOMA-IR, and placental A-FABP were significantly higher in pre-eclampsia patients and the level of HDL was obviously lower than in the control group. Serum A-FABP was positively correlated with FINS, TG, TC, and HOMA-IR, and placental A-FABP was negatively correlated with HDL in pre-eclampsia patients. In the control group, serum A-FABP was positively correlated only with TG, and uncorrelated with the other indices (P > 0.05). CONCLUSION: The level of A-FABP was correlated with insulin resistance and indices of glucolipid metabolism in pre-eclampsia patients. High-levels of A-FABP might increase insulin resistance by causing glucose and lipid metabolism disorders and ultimately inducing the occurrence and development of pre-eclampsia.

Tetrablock Metallopolymer Electrochromes.

Multi-block polymers are highly desirable for their addressable functions that are both unique and complementary among the blocks. With metal-containing polymers, the goal is even more challenging insofar as the metal properties may considerably extend the materials functions to sensing, catalysis, interaction with metal nanoparticles, and electro- or photochrome switching. Ring-opening metathesis polymerization (ROMP) has become available for the formation of living polymers using highly efficient initiators such as the 3rd generation Grubbs catalyst [RuCl2 (NHC)(=CHPh)(3-Br-C5 H4 N)2 ], 1. Among the 24 possibilities to introduce 4 blocks of metallopolymers into a tetrablock metallocopolymer by ROMP using the catalyst 1, two viable pathways are disclosed. The synthesis, characterization, electrochemistry, electron-transfer chemistry, and remarkable electrochromic properties of these new nanomaterials are presented.

New ROMP Synthesis of Ferrocenyl Dendronized Polymers.

First- and second-generation Percec-type dendronized ferrocenyl norbornene macromonomers containing, respectively, three and nine ferrocenyl termini are synthesized and polymerized by ring-opening metathesis polymerization using Grubbs' third-generation olefin metathesis catalyst with several monomer/catalyst feed ratios between 10 and 50. The rate of polymerization is highly dependent on the generation of the dendronized macromonomers, but all these ring-opening metathesis polymerization reactions are controlled, and near-quantitative monomer conversions are achieved. The numbers of ferrocenyl groups obtained are in agreement with the theoretical ones according to the cyclic voltammetry studies as determined using the Bard-Anson method.

Electrostatic Assembly of Functional and Macromolecular Ferricinium Chloride-Stabilized Gold Nanoparticles.

Substituted ferrocenes with various stereoelectronic effects including a ferrocene-terminated dendrimer in ether reduce aqueous HAuCl4 to gold nanoparticles (AuNPs) by interfacial electron transfer. The dependence on the stirring speed plays a crucial role, and the stereoelectronic influences on the reaction rates are dramatic. With a ferrocene-containing polymer, the reaction is conducted using an homogeneous THF/water medium, also forming AuNPs. Fully stable functional, dendritic and polymeric ferricinium chloride-stabilized AuNPs are obtained with core sizes between 13 and 35 nm, an optimal size range for potential biomedical applications. Finally the ferricinium coating of the Au nanoparticles is replaced by a more electron-rich ferricinium derivative by exergonic redox reaction with the corresponding ferrocene derivative.

Diblock Polyelectrolytic Copolymers Containing Cationic Iron and Cobalt Sandwich Complexes: Living ROMP Synthesis and Redox Properties.

Diblock metallopolymer polyelectrolytes containing the two redox-robust cationic sandwich units [CoCp'Cp](+) and [FeCp'(η(6)-C6 Me6)](+) (Cp = η(5)-C5 H5; Cp' = η(5)-C5H4-) as hexafluorophosphate ([PF6](-)) salts are synthesized by ring-opening metathesis polymerization using Grubbs' third generation catalyst. Their electrochemical properties show full chemical and electrochemical reversibilities allowing fine determination of the copolymer molecular weight using Bard-Anson's electrochemical method by cyclic voltammetry.