Sunlight-Induced RAFT Synthesis of Multifaceted Glycopolymers with Surface Anchoring, In Situ AgNP Formation, and Antibacterial Properties

A multifaceted glycopolymer is designed for the convenient and universal fabrication of antibacterial surfaces. Sunlight-induced living-radical polymerization in the presence of a reversible addition–fragmentation chain-transfer agent without a photoinitiator was applied to obtain well-designed multifunctional glycopolymers containing three functional groups that can complex with a silver ion, bind to different surfaces, and form silver nanoparticles in situ. The polymerization behavior and the effects of the concentration of the three monomers have been investigated. The obtained polymers can be used to effectively modify a variety of surfaces [silicon wafer, poly­(dimethylsiloxane), and stainless steel] and the modification is characterized by contact-angle studies, Fourier transform infrared, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy. In addition, the effect of the composition of the polymers on the antibacterial properties of different surfaces has been studied

Multifunctional, Degradable Wearable Sensors Prepared with an Initiator and Crosslinker-Free Method

The present zwitterionic hydrogel-based wearable sensor exhibits various limitations, such as limited degradation capacity, unavoidable toxicity resulting from initiators, and poor mechanical properties that cannot satisfy practical demands. Herein, we present an initiator and crosslinker-free approach to prepare polyethylene glycol (PEG)@poly­[2-(methacryloyloxy)­ethyl] dimethyl-(3-sulfopropyl) (PSBMA) interpenetrating polymer network (IPN) hydrogels that are self-polymerized via sunlight-induced and non-covalent crosslinking through electrostatic interaction and hydrogen bonding among polymer chains. The PEG@PSBMA IPN hydrogel possesses tissue-like softness, superior stretchability (∼2344.6% elongation), enhanced fracture strength (∼39.5 kPa), excellent biocompatibility, antibacterial property, reliable adhesion, and ionic conductivity. Furthermore, the sensor based on the IPN hydrogel demonstrates good sensitivity and cyclic stability, enabling effective real-time monitoring of human body activities. Moreover, it is worth noting that the excellent degradability in the saline solution within 8 h makes the prepared hydrogel-based wearable sensor free from the electronic device contamination. We believe that the proposed strategy for preparing physical zwitterionic hydrogels will pave the way for fabricating eco-friendly wearable devices

Multifunctional, Degradable Wearable Sensors Prepared with an Initiator and Crosslinker-Free Method

The present zwitterionic hydrogel-based wearable sensor exhibits various limitations, such as limited degradation capacity, unavoidable toxicity resulting from initiators, and poor mechanical properties that cannot satisfy practical demands. Herein, we present an initiator and crosslinker-free approach to prepare polyethylene glycol (PEG)@poly­[2-(methacryloyloxy)­ethyl] dimethyl-(3-sulfopropyl) (PSBMA) interpenetrating polymer network (IPN) hydrogels that are self-polymerized via sunlight-induced and non-covalent crosslinking through electrostatic interaction and hydrogen bonding among polymer chains. The PEG@PSBMA IPN hydrogel possesses tissue-like softness, superior stretchability (∼2344.6% elongation), enhanced fracture strength (∼39.5 kPa), excellent biocompatibility, antibacterial property, reliable adhesion, and ionic conductivity. Furthermore, the sensor based on the IPN hydrogel demonstrates good sensitivity and cyclic stability, enabling effective real-time monitoring of human body activities. Moreover, it is worth noting that the excellent degradability in the saline solution within 8 h makes the prepared hydrogel-based wearable sensor free from the electronic device contamination. We believe that the proposed strategy for preparing physical zwitterionic hydrogels will pave the way for fabricating eco-friendly wearable devices

Chemically Modified Surface Having a Dual-Structured Hierarchical Topography for Controlled Cell Growth

This report describes a technique for fabricating dual-structured hierarchical surface topography on the surface of polydimethylsiloxane (PDMS) films through simply replicating prefabricated patterns and wrinkling PDMS films. To enhance the biocompatibility of PDMS films, we synthesize a biocompatible dopamine-glycopolymer, which is utilized to modify the chemical feature of the PDMS surface. Dopamine component in this copolymer is introduced for the formation of a carbohydrate layer on the surface of PDMS films because of its excellent adhesion. The carbohydrate component in this copolymer enhances the interactions between cells and PDMS films. We investigate the influence of the chemical and topographical surface properties of the extracellular matrix on fibroblast cell growth. The coupling of the dopamine-glycopolymer coating and hierarchical topography produces the best induction effect on the alignment of cells

Multifunctional, Degradable Wearable Sensors Prepared with an Initiator and Crosslinker-Free Method

The present zwitterionic hydrogel-based wearable sensor exhibits various limitations, such as limited degradation capacity, unavoidable toxicity resulting from initiators, and poor mechanical properties that cannot satisfy practical demands. Herein, we present an initiator and crosslinker-free approach to prepare polyethylene glycol (PEG)@poly­[2-(methacryloyloxy)­ethyl] dimethyl-(3-sulfopropyl) (PSBMA) interpenetrating polymer network (IPN) hydrogels that are self-polymerized via sunlight-induced and non-covalent crosslinking through electrostatic interaction and hydrogen bonding among polymer chains. The PEG@PSBMA IPN hydrogel possesses tissue-like softness, superior stretchability (∼2344.6% elongation), enhanced fracture strength (∼39.5 kPa), excellent biocompatibility, antibacterial property, reliable adhesion, and ionic conductivity. Furthermore, the sensor based on the IPN hydrogel demonstrates good sensitivity and cyclic stability, enabling effective real-time monitoring of human body activities. Moreover, it is worth noting that the excellent degradability in the saline solution within 8 h makes the prepared hydrogel-based wearable sensor free from the electronic device contamination. We believe that the proposed strategy for preparing physical zwitterionic hydrogels will pave the way for fabricating eco-friendly wearable devices

Simple and Green Strategy for the Synthesis of “Pathogen-Mimetic” Glycoadjuvant@AuNPs by Combination of Photoinduced RAFT and Bioinspired Dopamine Chemistry

Innate immune responses recognizing pathogen associated molecular patterns (PAMPs) play a crucial role in adaptive immunity. Toll-like receptors (TLRs) and C-type lectin receptors (CLRs) contribute to antigen capture, uptake, presentation and activation of immune responses. In this contribution, metal-free reversible addition–fragmentation chain transfer (RAFT) polymerization of <i>N</i>-3,4-dihydroxybenzenethyl methacrylamide (DMA) and 2-(methacrylamido) glucopyranose (MAG) under sunlight irradiation using 2-cyanoprop-2-yl-α-dithionaphthalate (CPDN) as iniferter agent, can be employed to fabricate the multivalent glycopolymer containing bioresponsive sugar group and multifunctional catechol functionalities. The polymerization behavior is investigated and it presents controlled features. Moreover, bioinspired dopamine chemistry can be successfully utilized to form in situ glycopolymer-coated gold nanoparticles (AuNPs) without the need of additional reducing reagent, design “pathogen-mimetic” glycoadjuvant recognized by both CLRs and TLRs. The synthetic glycoadjuvant is found to enhance the adjuvant activity as “infected signals” in vitro

Synthesis of Hemoglobin Conjugated Polymeric Micelle: A ZnPc Carrier with Oxygen Self-Compensating Ability for Photodynamic Therapy

Photodynamic therapy (PDT) is a promising singlet oxygen (¹O₂) mediated clinical treatment for many tumors. As the source of ¹O₂, oxygen plays an important role in the curative effect of PDT. However, the facts of photochemical depletion of oxygen and the intrinsic hypoxic microenvironment of tumors remain the major challenges. In this work, a novel photosensitizer carrier with oxygen self-compensating ability was designed for PDT. It was synthesized via chemical conjugation of hemoglobin (Hb) to polymeric micelles formed by triblock copolymers of poly­(ethylene glycol)-<i>block</i>-poly­(acrylic acid)-<i>block</i>-polystyrene (PEG-<i>b</i>-PAA-<i>b</i>-PS). The PEG-<i>b</i>-PAA-<i>b</i>-PS and resultant micelles in aqueous solution were comprehensively characterized by means of FTIR, ¹H NMR, GPC, DLS, TEM, and fluorescence spectroscopy. The oxygen-binding capacity and antioxidative activity of the Hb conjugated micelles were evaluated via UV–vis spectroscopy. In addition, compared with the control micelles without Hb, the Hb conjugated photosensitizer carrier was able to generate more ¹O₂ and exert greater photocytotoxicity on Hela cells in vitro

Degradable Selenium-Containing Polymers for Low Cytotoxic Antibacterial Materials

Developing biodegradable cationic polymers with high antibacterial efficiency and low cytotoxicity is of great significance in biological applications. Selenium is an essential trace element for the human body, and selenium-containing compounds are promising in various health-related applications. To combine selenium with biodegradability, selenide-functionalized polycaprolactones (PCL) with different hydrophobic substituents were synthesized followed by selenoniumization. The optimal polyselenonium salt showed excellent antibacterial activity with an MBC of 2 μg mL–1 and an MIC of 1 μg mL–1 and exhibited good biocompatibility before and after degradation. In addition, the obtained selenium polymer can be well blended with commercial PCL by electrospinning, and films with good antibacterial activity were prepared. This work enriches the knowledge of selenium derivatives and lays a foundation for follow-up research on selenium cationic polymers in the antimicrobial field

One Stone Kills Three Birds: Novel Boron-Containing Vesicles for Potential BNCT, Controlled Drug Release, and Diagnostic Imaging

A new conjugate polymer was prepared by an efficient thiol–ene coupling of one carborane with a linear PEG chain (<i>M</i>_n = 2,000 g/mol), and each carborane was further labeled with a fluorescence rhodamine dye. Such a novel polymer can associate in water to form narrowly distributed spherical vesicles, which were characterized using a range of methods, including laser light scattering, confocal laser scanning microscopy, and TEM. The vesicular structure is potentially multifunctional in biomedical applications, namely, serving as a boron neutron capture therapy (BNCT) agent, a hydrophilic drug carrier, and a diagnostic imaging fluorescent probe. As expected, either cleaving the thiol–ene linked PEO chain by esterase or destroying carborane by neutron irradiation results in a dismantlement of such a vesicle structure to release its encapsulated drugs. Its potential biomedical applications have been evaluated in vitro and in vivo. Our preliminary results reveal that these small vesicles can be quickly taken up by cells and have an enhanced stability in the bloodstream so that their targeting to specific cancer cells becomes feasible

Numerical study of inhomogeneous deformation of gas diffusion layers on proton exchange membrane fuel cells performance

Gas diffusion layers play a critical role in the operation of proton exchange membrane fuel cells. As the most compressible component in proton exchange membrane fuel cells, the non-uniform deformation mainly occurs on the interface between bipolar plates and gas diffusion layers caused by the special channel-rib geometry of the flow field, which results in a non-uniform variation of physical properties of gas diffusion layers, such as porosity, effective electrical conductivity, and gas diffusivity, consequently affects the cell performance. In this paper, a two-dimensional, across-the-channel, multi-physics and two-phase flow model based on the spherical agglomerate assumption is developed to investigate the complicated relationships between the non-uniform deformation and variation of physical properties of the gas diffusion layers, as well as the cell performance. A modified diffusion coefficient is introduced to describe the effect of the variation of species concentration on the effective diffusion coefficient based on the Bruggeman formula. Simulation results show that an optimal cell performance can be achieved by balancing the variation of porosity, effective electrical conductivity, and effective gas diffusion coefficient with respect to different degrees of deformation of gas diffusion layers