Direct Electrochemistry of Glucose Dehydrogenase-Functionalized Polymers on a Modified Glassy Carbon Electrode and Its Molecular Recognition of Glucose.

A glucose biosensor was layer-by-layer assembled on a modified glassy carbon electrode (GCE) from a nanocomposite of NAD(P)+-dependent glucose dehydrogenase, aminated polyethylene glycol (mPEG), carboxylic acid-functionalized multi-wall carbon nanotubes (fMWCNTs), and ionic liquid (IL) composite functional polymers. The electrochemical electrode was denoted as NF/IL/GDH/mPEG-fMWCNTs/GCE. The composite polymer membranes were characterized by cyclic voltammetry, ultraviolet-visible spectrophotometry, electrochemical impedance spectroscopy, scanning electron microscopy, and transmission electron microscopy. The cyclic voltammogram of the modified electrode had a pair of well-defined quasi-reversible redox peaks with a formal potential of -61 mV (vs. Ag/AgCl) at a scan rate of 0.05 V s-1. The heterogeneous electron transfer constant (ks) of GDH on the composite functional polymer-modified GCE was 6.5 s-1. The biosensor could sensitively recognize and detect glucose linearly from 0.8 to 100 µM with a detection limit down to 0.46 µM (S/N = 3) and a sensitivity of 29.1 nA µM-1. The apparent Michaelis-Menten constant (Kmapp) of the modified electrode was 0.21 mM. The constructed electrochemical sensor was compared with the high-performance liquid chromatography method for the determination of glucose in commercially available glucose injections. The results demonstrated that the sensor was highly accurate and could be used for the rapid and quantitative determination of glucose concentration.

Stimuli-Responsive Drug Delivery Systems for the Diagnosis and Therapy of Lung Cancer.

Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer death worldwide. Numerous drugs have been developed to treat lung cancer patients in recent years, whereas most of these drugs have undesirable adverse effects due to nonspecific distribution in the body. To address this problem, stimuli-responsive drug delivery systems are imparted with unique characteristics and specifically deliver loaded drugs at lung cancer tissues on the basis of internal tumor microenvironment or external stimuli. This review summarized recent studies focusing on the smart carriers that could respond to light, ultrasound, pH, or enzyme, and provided a promising strategy for lung cancer therapy.

One-step modification of fabrics with bioinspired polydopamine@octadecylamine nanocapsules for robust and healable self-cleaning performance.

An in-situ polymerization to coat fabrics with polydopamine-encapsulated octadecylamine endows the fabrics with self-cleaning and self-healing abilities. The treated fabric exhibits self-healing after losing its hydrophobicity. It is durable against washing and mechanical abrasion without changing the hydrophobicity. Thanks to the versatile adhesive property of polydopamine, the approach is compatibile with a variety of substrates, such as fabrics, glass, sponge, paper, and polymeric materials.

UV-absorbent lignin-based multi-arm star thermoplastic elastomers.

Lignin-grafted copolymers, namely lignin-graft-poly(methyl methacrylate-co-butyl acrylate) (lignin-g-P(MMA-co-BA)), are synthesized via "grafting from" atom transfer radical polymerization (ATRP) with the aid of lignin-based macroinitiators. By manipulating the monomer feed ratios of MMA/BA, grafted copolymers with tunable glass transition temperatures (-10-40 °C) are obtained. These copolymers are evaluated as sustainable thermoplastic elastomers (TPEs). The results suggest that the mechanical properties of these TPEs lignin-g-P(MMA-co-BA) copolymers are improved significantly by comparing with those of linear P(MMA-co-BA) copolymer counterparts, and the elastic strain recovery is nearly 70%. Lignin-g-P(MMA-co-BA) copolymers exhibit high absorption in the range of the UV spectrum, which might allow for applications in UV-blocking coatings.

M-MDSCs mediated trans-BBB drug delivery for suppression of glioblastoma recurrence post-standard treatment.

We found that immunosuppressive monocytic-myeloid-derived suppressor cells (M-MDSCs) were more likely to be recruited by glioblastoma (GBM) through adhesion molecules on GBM-associated endothelial cells upregulated post-chemoradiotherapy. These cells are continuously generated during tumor progression, entering tumors and expressing PD-L1 at a high level, allowing GBM to exhaust T cells and evade attack from the immune system, thereby facilitating GBM relapse. αLy-6C-LAMP is composed of (i) drug cores with slightly negative charges condensed by cationic protamine and plasmids encoding PD-L1 trap protein, (ii) pre-formulated cationic liposomes targeted to Ly-6C for encapsulating the drug cores, and (iii) a layer of red blood cell membrane on the surface for effectuating long-circulation. αLy-6C-LAMP persistently targets peripheral, especially splenic, M-MDSCs and delivers secretory PD-L1 trap plasmids, leveraging M-MDSCs to transport the plasmids crossing the blood-brain barrier (BBB), thus expressing PD-L1 trap protein in tumors to inhibit PD-1/PD-L1 pathway. Our proposed drug delivery strategy involving intermediaries presents an efficient cross-BBB drug delivery concept that incorporates live-cell targeting and long-circulating nanotechnology to address GBM recurrence.

Skin-adhesive lignin-grafted-polyacrylamide/hydroxypropyl cellulose hydrogel sensor for real-time cervical spine bending monitoring in human-machine Interface.

Developing a straightforward method to produce conductive hydrogels with excellent mechanical properties, self-adhesion, and biocompatibility remains a significant challenge. While current approaches aim to enhance mechanical performance, they often require additional steps or external forces for fixation, leading to increased production time and limited practicality. A novel lignin-grafted polyacrylamide/hydroxypropyl cellulose hydrogel (L-g-PAM/HPC hydrogel) with a semi-interpenetrating polymer network structure had been developed in this research that boasted exceptional adhesion to the skin (∼68 kPa) and stretchability properties (∼1637 %) compared to PAM-based hydrogels. By incorporating conductive additives such as silver nanowires and carbon nanocages to construct a bridge-like structure within the hydrogel matrix, the resulting AgC@L-g-PAM/HPC hydrogel exhibited impressive electrical conductivity, surpassing that of other PAM-based hydrogels relying on MXene, with a maximum value of 0.76 S/m. Furthermore, the AgC@L-g-PAM/HPC hydrogel retained its efficient electrical signal transmission capability even under mechanical stress. These make it an ideal flexible strain sensor capable of detecting various human motions. In this study, a smart real-time monitoring system was successfully developed for tracking cervical spine bending, serving as an extension for monitoring human activities.

Combination of acid treatment and dual network fabrication to stretchable cellulose based hydrogels with tunable properties.

Cellulose based hydrogels with a relatively high stretchability were fabricated in the NaOH/urea system via sequential chemical crosslinking and dual network fabrication. The first step involved crosslinking of cellulose using epichlorohydrin as a crosslinker. Cryo-electron microscopy analysis revealed the utilization of diluted acid to treat hydrogels significantly affected the morphology of the first network and improved the mechanical properties. After diffusion of precursors into the first network, the dual network hydrogels were generated after the UV light-initiated polymerization. Raman spectroscopy demonstrated a spatial distribution of second networks within the first network. The compression strength of hydrogels synthesized under the optimized conditions was effectively enhanced from 0.04 MPa to 10.9 MPa. In addition, the tensile properties of hydrogels were easily adjusted via copolymerization of acrylic acid with acrylamide. The highest strain could reach 219.5% with a tensile strength of 1.4 MPa. This work provides a promising and simple strategy to develop a cellulose based hydrogel with enhanced and tunable mechanical properties for wide applications.

Unexpected role of amphiphilic lignosulfonate to improve the storage stability of urea formaldehyde resin and its application as adhesives.

As the second-largest natural polymer, the utilization of lignin for practical applications has attracted increasing attention. In this study, lignosulfonate was employed to enhance the storage stability of urea formaldehyde (UF) resins. Cryo-scanning electron microscopy was firstly used to observe the influence of lignosulfonate addition on the colloidal morphology of UF resin. Moreover, adding lignosulfonate at different stages during the UF resins synthesis was also investigated to reveal its effect on storage stability. The potential interaction between lignosulfonate and UF resins was then analyzed via FT-IR, 13C CPMAS NMR, and zeta potential. It has been observed that lignosulfonate could increase the electrostatic repulsion of UF resins to avoid aging. No chemical reaction between UF resins and lignosulfonate was observed. After the elucidation of potential interaction, the effect of lignosulfonate on the curing process, thermal stability and adhesive performance of UF resins was systematically evaluated. Finally, as adhesives to fabricate eucalyptus plywood, the shear strength and formaldehyde release of UF resins with 20% addition of lignosulfonate could reach 0.88 MPa and 0.12 mg/L, respectively. Due to the excellent performance, low cost and wide availability of lignosulfonate, it might be industrially used as a stabilizer in the UF resins production.

Highly mechanical properties nanocomposite hydrogels with biorenewable lignin nanoparticles.

Biorenewable polymers from natural resources have attracted a greater attention of the research for different applications. In this work, renewable lignin nanoparticles (LNP) were employed as cross-linking junctions to prepare high mechanical properties hydrogel, polyacrylamide/lignin nanoparticle (PAM/LNP) nanocomposite hydrogel. The hydrogel exhibits high compressive and tensile strengths as well as excellent recoverability. The fracture strength of the PAM/LNP hydrogel under compressive stress is on the order of megapascals, which is several orders of magnitude higher than those of pure PAM hydrogel. The synergic improving effect of nanocomposite network structure and the strong H-bonding between polymer chains endow the hydrogel with an excellent mechanism of distributing the applied load. Considering good mechanical properties, simple synthesis methods and noncytotoxicity, this high performance hydrogel material has potential applications in biomedical fields, such as tissue engineering or regeneration, artificial muscles, strong underwater antifouling materials, and so on.

Sustainable elastomers derived from cellulose, rosin and fatty acid by a combination of "graft from" RAFT and isocyanate chemistry.

Utilization of natural sustainable feedstock to fabricate polymers has attracted remarkable attention. In this work, we reported a strategy to prepare a series of grafted copolymers from rosin, fatty acids and ethyl cellulose. The process involved the preparation of EC-based macro-RAFT agent through a simple esterification reaction, followed by a "grafting from" reversible addition-fragmentation chain transfer polymerization (RAFT) of DAGMA (derived from rosin) and LMA (derived from fatty acid) to achieve a class of EC-g-P(DAGMA-co-LMA) graft copolymers with a tunable Tg tuned by the DAGMA/LMA molar ratio. Then, hexamethylene diisocyanate (HDI) was used to crosslink these graft copolymers. The mechanical and dynamic thermo-mechanical properties of tests showed that elastic recovery values of copolymers were enhanced to 90%, as compared to the un-crosslinked samples. Additionally, all these polymers showed an excellent UV absorption performance. This study provides a facile way to fabricate biobased elastomeric materials with improved mechanical properties.

Polymer brushes on structural surfaces: a novel synergistic strategy for perfectly resisting algae settlement.

The current paper reports a novel model of a marine antibiofouling surface based on polymer brushes on a wrinkled silicone elastomer. Polymer brushes (POEGMA and PSPMA) were grafted via surface-initiated atom transfer radical polymerization (SI-ATRP). Successful grafting was verified with various characterization techniques including infrared spectroscopy, X-ray photoelectron spectroscopy and contact angle measurements. A series of laboratory static and dynamic bioassays as well as field immersion tests were carried out to systematically investigate the relationship between surface chemistry, surface topography and antifouling properties. The results indicated that the adhesion of marine organisms was strongly influenced by the surface chemistry composition and surface topography structure. The synergistic effect of the surface chemistry, surface topography and bulk properties of the substrates endowed the new marine coatings with excellent antifouling properties.

Bio-based phenols and fuel production from catalytic microwave pyrolysis of lignin by activated carbons.

The aim of this study is to explore catalytic microwave pyrolysis of lignin for renewable phenols and fuels using activated carbon (AC) as a catalyst. A central composite experimental design (CCD) was used to optimize the reaction condition. The effects of reaction temperature and weight hourly space velocity (WHSV, h(-1)) on product yields were investigated. GC/MS analysis showed that the main chemical compounds of bio-oils were phenols, guaiacols, hydrocarbons and esters, most of which were ranged from 71% to 87% of the bio-oils depending on different reaction conditions. Bio-oils with high concentrations of phenol (45% in the bio-oil) were obtained. The calorific value analysis revealed that the high heating values (HHV) of the lignin-derived biochars were from 20.4 to 24.5 MJ/kg in comparison with raw lignin (19 MJ/kg). The reaction mechanism of this process was analyzed.

A review of catalytic hydrodeoxygenation of lignin-derived phenols from biomass pyrolysis.

Catalytic hydrodeoxygenation (HDO) of lignin-derived phenols which are the lowest reactive chemical compounds in biomass pyrolysis oils has been reviewed. The hydrodeoxygenation (HDO) catalysts have been discussed including traditional HDO catalysts such as CoMo/Al(2)O(3) and NiMo/Al(2)O(3) catalysts and transition metal catalysts (noble metals). The mechanism of HDO of lignin-derived phenols was analyzed on the basis of different model compounds. The kinetics of HDO of different lignin-derived model compounds has been investigated. The diversity of bio-oils leads to the complexities of HDO kinetics. The techno-economic analysis indicates that a series of major technical and economical efforts still have to be investigated in details before scaling up the HDO of lignin-derived phenols in existed refinery infrastructure. Examples of future investigation of HDO include significant challenges of improving catalysts and optimum operation conditions, further understanding of kinetics of complex bio-oils, and the availability of sustainable and cost-effective hydrogen source.