Superstrong Noncovalent Interface between Melamine and Graphene Oxide

A comprehensive review on the progress and challenges of tetrahydroisoquinoline derivatives as a promising therapeutic agent to treat Alzheimer's disease

Alzheimer's disease (AD) is the most common and irreversible neurodegenerative disorder worldwide. While the precise mechanism behind this rapid progression and multifaceted disease remains unknown, the numerous drawbacks of the available therapies are prevalent, necessitating effective alternative treatment methods. In view of the rising demand for effective AD treatment, numerous reports have shown that tetrahydroisoquinoline (THIQ) is a valuable scaffold in various clinical medicinal molecules and has a promising potential as a therapeutic agent in treating AD due to its significant neuroprotective, anti-inflammatory, and antioxidative properties via several mechanisms that target the altered signaling pathways. Therefore, this review comprehensively outlines the potential application of THIQ derivatives in AD treatment and the challenges in imparting the action of these prospective therapeutic agents. The review emphasizes a number of THIQ derivatives, including Dauricine, jatrorrhizine, 1MeTIQ, and THICAPA, that have been incorporated in AD studies in recent years. Subsequently, a dedicated section of the review briefly discusses the emerging potential benefits of multi-target therapeutics, which lie in their ability to be integrated with alternative therapeutics. Eventually, this review elaborates on the rising challenges and future recommendations for the development of therapeutic drug agents to treat AD effectively. In essence, the valuable research insights of THIQ derivatives presented in this comprehensive review would serve as an integral reference for future studies to develop potent therapeutic drugs for AD research.

Strain Engineering of Ion-Coordinated Nanochannels in Nanocellulose

Expanding the interlayer spacing plays a significant role in improving the conductivity of a cellulose-based conductor. However, it remains a challenge to regulate the cellulose nanochannel expanded by ion coordination. Herein, starting from multiscale mechanics, we proposed a strain engineering method to regulate the interlayer spacing of the cellulose nanochannels. First-principles calculations were conducted to select the most suitable ions for coordination. Large-scale molecular dynamics simulations were performed to reveal the mechanism of interlayer spacing expansion by the ion cross-linking. Combining the shear-lag model, we established the relationship between interfacial cross-link density and interlayer spacing of an ion-coordinated cellulose nanochannel. Consequently, fast ion transport and current regulation were realized via the strain engineering of nanochannels, which provides a promising strategy for the current regulation of a cellulose-based conductor.

An elastic MOF/graphene aerogel with high photothermal efficiency for rapid removal of crude oil

Due to the frequent spill accidents during crude oil exploration and transport, to rapidly cleanup crude oil and eliminate the environmental pollution of oil spill is in high demand. In this work, a three-dimensional graphene aerogel (MEGA) with high elasticity, photothermal conversion capacity and adsorption capacity was prepared for rapid removal of crude oil. The results showed that the as-prepared MEGA exhibited a layered structure, the octahedral HKUST-1 nanoparticles and hydrophobic polydimethylsiloxane (PDMS) coatings were uniformly deposited on the surface. Such a hierarchical micro-nano porous structure not only improved the aerogel's hydrophobicity (water contact angle in air up to 152.7°), but also endowed it with strong oil adsorption capacity (41-118 times of its own weight). Especially, the MEGA showed excellent photothermal conversion capacity. Under light irradiation, its temperature raised to 80 ℃ from room temperature in 100 s. As a result, the adsorption for one drop of crude oil by MEGA was shortened from 5 h to 40 s, comparing with that in dark condition. In addition, the MEGA showed remarkable elasticity and mechanical stability, it could maintain more than 90% efficiency after 10 adsorption-compression cycles. This study suggests that the prepared MEGA has great potential for rapid removal of crude oil.

Advanced nanomaterials for modulating Alzheimer's related amyloid aggregation

Alzheimer's disease (AD) is a common neurodegenerative disease that brings about enormous economic pressure to families and society. Inhibiting abnormal aggregation of Aβ and accelerating the dissociation of aggregates is treated as an effective method to prevent and treat AD. Recently, nanomaterials have been applied in AD treatment due to their excellent physicochemical properties and drug activity. As a drug delivery platform or inhibitor, various excellent nanomaterials have exhibited potential in inhibiting Aβ fibrillation, disaggregating, and clearing mature amyloid plaques by enhancing the performance of drugs. This review comprehensively summarizes the advantages and disadvantages of nanomaterials in modulating amyloid aggregation and AD treatment. The design of various functional nanomaterials is discussed, and the strategies for improved properties toward AD treatment are analyzed. Finally, the challenges faced by nanomaterials with different dimensions in AD-related amyloid aggregate modulation are expounded, and the prospects of nanomaterials are proposed.

Selective Polyetheretherketone Implants Combined with Graphene Cause Definitive Cell Adhesion and Osteogenic Differentiation

INTRODUCTION

Polyetheretherketone (PEEK) has good biosafety and chemical stability for bone repair. However, PEEK is biologically inert and cannot promote bone apposition. This study investigated whether graphene-modified PEEK (G-PEEK) could improve cell adhesion and osteogenic differentiation.

METHODS

G-PEEK was prepared by melted blending and was characterized. In vitro, the biocompatibility of G-PPEK and the ability to promote cell adhesion and osteogenic differentiation in rabbit bone marrow mesenchymal stem cells (rBMSCs) were examined using live and dead cell double staining, the cell counting kit-8 (CCK-8) assay, immunofluorescence and quantitative real-time PCR (qRT‒PCR). An in vivo rabbit extra-articular graft-to-bone healing model was established. At 4 and 12 weeks after surgery, CT analysis and histological evaluation were performed.

RESULTS

In vitro, G-PEEK significantly improved the adhesion and proliferation of rBMSCs, with good biocompatibility. In vivo, G-PEEK promoted new bone formation at the site of the bone defect.

CONCLUSION

G-PEEK showed excellent osteogenesis performance, which promises new applications in implant materials.

Intrinsic kink deformation in nanocellulose

Sharp bends can be widely observed in isolated cellulose nanofibrils (CNFs) after mechanical treatment, referred to as kink dislocations that are previously found in wood cell walls under compression. The non-Gaussian distribution of kink angle implies some inherent deformation behaviors of cellulose nanocrystals (CNCs) hidden in the formation of kink dislocations in CNFs. We herein perform molecular dynamics simulations to investigate the kink deformation of nanocellulose. It is interesting to find an intrinsic deformation mode of Iβ CNCs under uniaxial compression, in which the metastable structure of kinked CNCs turns out to be the triclinic Iα phase with twin boundaries originated from interlayer dislocation-induced allomorphic transition. An intrinsic kink angle (~60°) is defined based on geometric traits of stable kinked CNCs. Moreover, the weakened intrachain hydrogen bonds in twin boundaries lead to exposed glycosidic bonds and damaged hydrogen-bonding networks, which would act as the origin of kink defects in nanocellulose.

Intranasal administration of dauricine loaded on graphene oxide: multi-target therapy for Alzheimer's disease

Alzheimer's disease (AD) is a degenerative disease of the central nervous system characterized by progressive cognitive and memory-related impairment. However, current therapeutic treatments have not proved sufficiently effective, mainly due to the complicated pathogenesis of the disease. In this study, a nano-formulation of graphene oxide (GO) loaded with dauricine (Dau) was investigated in terms of the combined anti-inflammatory and anti-oxidative stress effects of Dau and the inhibition of misfolding and aggregation of the amyloid-β (Aβ) protein by GO. Both in vivo and in vitro models were induced using Aβ_1-42, and the formulation was administered nasally in mice. The results showed that GO loaded with Dau greatly reduced oxidative stress through increasing superoxide dismutase levels and decreasing reactive oxygen species and malondialdehyde levels in vitro; it also alleviated the cognitive memory deficits and brain glial cell activation in mice with Aβ_1-42-induced AD. This proved that GO loaded with Dau could protect against Aβ_1-42-induced oxidative damage and apoptosis in both in vitro and in vivo AD models; therefore, GO loaded with Dau has the potential to be an effective and agent for the rapid treatment of AD.

Strengthening and Toughening Hierarchical Nanocellulose via Humidity-Mediated Interface

Undoubtedly humidity is a non-negligible and sensitive problem for cellulose, which is usually regarded as one disadvantage to cellulose-based materials because of the uncontrolled deformation and mechanical decline. But the lack of an in-depth understanding of the interfacial behavior of nanocellulose in particular makes it challenging to maintain anticipated performance for cellulose-based materials under varied relative humidity (RH). Starting from multiscale mechanics, we herein carry out first-principles calculations and large-scale molecular dynamics simulations to demonstrate the humidity-mediated interface in hierarchical cellulose nanocrystals (CNCs) and associated deformation modes. More intriguingly, the simulations and subsequent experiments reveal that water molecules (moisture) as the interfacial media can strengthen and toughen nanocellulose simultaneously within a suitable range of RH. From the perspective of interfacial design in materials, the anomalous mechanical behavior of nanocellulose with humidity-mediated interfaces indicates that flexible hydrogen bonds (HBs) play a pivotal role in the interfacial sliding. The difference between CNC-CNC HBs and CNC-water-CNC HBs triggers the humidity-mediated interfacial slipping in nanocellulose, resulting in the arising of a pronounced strain hardening stage and the suppression of strain localization during uniaxial tension. This inelastic deformation of nanocellulose with humidity-mediated interfaces is similar to the Velcro-like behavior of a wet wood cell wall. Our investigations give evidence that the humidity-mediated interface can promote the mechanical enhancement of nanocellulose, which would provide a promising strategy for the bottom-up design of cellulose-based materials with tailored mechanical properties.

Recent advances in graphene-family nanomaterials for effective drug delivery and phototherapy

INTRODUCTION

Owing to the unique properties of graphene, including large specific surface area, excellent thermal conductivity, and optical absorption, graphene-family nanomaterials (GFNs) have attracted extensive attention in biomedical applications, particularly in drug delivery and phototherapy.

AREAS COVERED

In this review, we point out several challenges involved in the clinical application of GFNs. Then, we provide an overview of the most recent publications about GFNs in biomedical applications, including diverse strategies for improving the biocompatibility, specific targeting and stimuli-responsiveness of GFNs for drug delivery, codelivery of drug and gene, photothermal therapy, photodynamic therapy, and multimodal combination therapy.

EXPERT OPINION

Although the application of GFNs is still in the preclinical stage, rational modification of GFNs with functional elements or making full use of GFNs-based multimodal combination therapy might show great potential in biomedicine for clinical application.

Noble-Metal-Free CdS Nanoparticle-Coated Graphene Oxide Nanosheets Favoring Electron Transfer for Efficient Photoreduction of CO2

Graphene oxide (GO) nanosheets are promising noble-metal-free catalysts. However, the catalytic activity and selectivity of GO are still very low. Herein, GO is first functionalized via noncovalent interactions by an aspartic acid modified anhydride having COOH groups to form A-GO. A-GO is more conductive and hydrophilic than GO and P-GO synthesized via functionalizing GO by a COOH-free anhydride. Then, we load CdS nanoparticles, which are responsible for absorbing light to produce charge carriers, on A-GO to fabricate a CdS/A-GO photocatalyst without noble metals for the photoreduction of CO₂ by H₂O. CdS/A-GO exhibits a higher photoreduction efficiency than that of CdS/GO and CdS/P-GO. The main carbon-based photoreduction product of CdS/A-GO is CH₃OH, whereas that of CdS/GO and CdS/P-GO is CO. The more conductive and hydrophilic A-GO triggers a more efficient electron transfer, CO₂ adsorption, and production of hydrogen atoms from H₂O dissociation, thus leading to the higher photoreduction efficiency and product change on CdS/A-GO. Besides, the COOH groups of the aspartic acid modified anhydride supply their hydrogen atoms to promote the conversion from CO₂ to CH₃OH on CdS/A-GO. Therefore, noncovalently functionalizing GO with different active species can efficiently improve the catalytic performance of GO. This opens a new way to design and construct noble-metal-free catalysts with enhanced activity and selectivity.