A new biomimetic nanozyme of hemin/graphdiyne oxide with superior peroxidase-like activity for colorimetric bioassays

Graphdiyne as an emerging sensor platform: Principles, synthesis and application

BACKGROUND

Graphdiyne (GDY) is a kind of carbon material, which has highly delocalized π-conjugated system and feasible green synthesis. Nowadays, the use of GDY substrate as a sensing platform has become a new research hotspot and is rapidly developing. However, its application as a sensor is still relatively overlook compared to other fields.

AIM OF REVIEW

This study is for the purpose of making researchers have a complete comprehensive understanding of GDY and its associated sensing platforms.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This study introduces the structure, unique characteristics, and synthesis progress of GDY material. Moreover, the article systematically summarizes the improvement of GDY-based sensors in life, health and environmental detection. It also discusses the opportunities and challenges of designing high-performance GDY-based sensing platforms with the assistance of machine learning and theoretical calculate. It has essential scientific and practical meaning for accelerating the development of sensing platforms which base on GDY, triggering unknown phenomena and knowledge of material research, and initiating unlimited space for scientific innovation.

Ferroptosis-inducing nanomedicine and targeted short peptide for synergistic treatment of hepatocellular carcinoma

The poor prognosis of hepatocellular carcinoma (HCC) is still an urgent challenge to be solved worldwide. Hence, assembling drugs and targeted short peptides together to construct a novel medicine delivery strategy is crucial for targeted and synergy therapy of HCC. Herein, a high-efficiency nanomedicine delivery strategy has been constructed by combining graphdiyne oxide (GDYO) as a drug-loaded platform, specific peptide (SP94-PEG) as a spear to target HCC cells, sorafenib, doxorubicin-Fe2+ (DOX-Fe2+), and siRNA (SLC7A11-i) as weapons to exert a three-path synergistic attack against HCC cells. In this work, SP94-PEG and GDYO form nanosheets with HCC-targeting properties, the chemotherapeutic drug DOX linked to ferrous ions increases the free iron pool in HCC cells and synergizes with sorafenib to induce cell ferroptosis. As a key gene of ferroptosis, interference with the expression of SLC7A11 makes the ferroptosis effect in HCC cells easier, stronger, and more durable. Through gene interference, drug synergy, and short peptide targeting, the toxic side effects of chemotherapy drugs are reduced. The multifunctional nanomedicine GDYO@SP94/DOX-Fe2+/sorafenib/SLC7A11-i (MNMG) possesses the advantages of strong targeting, good stability, the ability to continuously induce tumor cell ferroptosis and has potential clinical application value, which is different from traditional drugs.

Smartphone and paper-based device for glucose monitoring using acetylene black-hemin nanozyme as catalyst

Glucose management is an important part of disease control for diabetes patients, thus the development of a rapid and real-time point of care testing (POCT) device for monitoring blood glucose is of great significance. In this work, a paper-based analytical device (PAD) is constructed by combining acetylene black (AB)-hemin complex modified filter paper as sensing platform with a smartphone as signal detector. Large specific surface area of AB decreases the self-associate and aggregate of hemin in aqueous solution, resulting in improved peroxidase-like activity of hemin. Compared with graphene oxide supported hemin, AB-hemin exhibits superior signal response on paper. Glucose oxidase (GOx) catalyzes the conversion of blood glucose to hydrogen peroxide, and then AB-hemin complex catalyzes the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue TMB oxidized products (TMB⁺) in the presence of hydrogen peroxide, thus achieving the visual detection of blood glucose. In optimal conditions, PAD provides an applicable linear range from 0.2 mM to 30 mM and a low limit of detection (LOD) (0.06 mM). Notably, the detection accuracy of the developed paper-based sensor is in good agreement with that of the commercially available blood glucose meter (p > 0.05). Moreover, the proposed PAD presents high recoveries from 95.4% to 112% (RSD ≤ 3.2%), and therefore holds great potential for glucose monitoring and diabetes diagnosis.

Recent advances in colorimetric sensors based on nanozymes with peroxidase-like activity

Nanozymes have been widely used to construct colorimetric sensors due to their advantages of cost-effectiveness, high stability, good biocompatibility, and ease of modification. The emergence of nanozymes greatly enhanced the detection sensitivity and stability of the colorimetric sensing platform. Recent significant research has focused on designing various sensors based on nanozymes with peroxidase-like activity for colorimetric analysis. However, with the deepening of research, nanozymes with peroxidase-like activity has also exposed some problems, such as weak affinity and low catalytic activity. In view of the above issues, existing investigations have shown that the catalytic properties of nanozymes can be improved by adding surface modification and changing the structure of nanomaterials. In this review, we summarize the recent trends and advances of colorimetric sensors based on several typical nanozymes with peroxidase-like activities, including noble metals, metal oxides, metal sulfides/metal selenides, and carbon and metal-organic frameworks (MOF). Finally, the current challenges and prospects of colorimetric sensors based on nanozymes with peroxidase-like activity are summarized and discussed to provide a reference for researchers in related fields.

Nanostructured Graphdiyne: Synthesis and Biomedical Applications

Graphdiyne (GDY) is a 2D carbon allotrope that features a one-atom-thick network of sp- and sp2-hybridized carbon atoms with high degrees of π conjugation. Due to its distinct electronic, chemical, mechanical, and magnetic properties, GDY has attracted great attention and shown great potential in various fields, such as catalysis, energy storage, and the environment. Preparation of GDY with various nanostructures, including 0D quantum dots, 1D nanotubes/nanowires/nanoribbons, 2D nanosheets/nanowalls/ordered stripe arrays, and 3D nanospheres, greatly improves its function and has propelled its applications forward. High biocompatibility and stability make GDY a promising candidate for biomedical applications. This review introduces the latest developments in fabrication of GDY-based nanomaterials with various morphologies and summarizes their propective use in the biomedical domain, specifically focusing on their potential advantages and applications for biosensing, cancer diagnosis and therapy, radiation protection, and tissue engineering.

Graphdiyne applications in sensors: A bibliometric analysis and literature review

Graphdiyne is a two-dimensional carbon nanomaterial synthesized artificially in 2010. Its outstanding performance is considered to have great potential in different fields. This article summarizes the work of graphdiyne in the sensing field by literature summary and bibliometrics analysis. The development of graphdiyne in the field of sensing has gone through a process from theoretical calculation to experimental verification. Especially in the last three years, there has been very rapid development. The theoretical calculations suggest that graphdiyne is an excellent gas sensing material, but there is little experimental evidence in this direction. On the contrary, graphdiyne has been widely reported in the field of electrochemical sensing. At the same time, graphdiyne can also be used as a molecular switch for DNA sequencing. Fluorescent sensors based on graphdiyne have also been reported. In general, the potential of graphdiyne in sensing still needs to be explored. Current research results do not show that graphdiyne has irreplaceable advantages in sensing. The bibliometric analysis used in this review also provides cooperative network analysis and co-citation analysis on this topic. This provides a reference for the audience wishing to undertake research on the topic. In addition, according to the analysis, we also listed the direction that which this field deserves attention in the future.

Graphdiyne Oxide Quantum Dots: The Enhancement of Peroxidase-like Activity and Their Applications in Sensing H2O2 and Cysteine

As one of the typical carbon nanomaterials, graphdiyne (GDY) with unique chemical, physical, and electronic properties has a great potential in various fields. Although it is an important member of carbon nanozymes, the research on its intrinsic enzyme mimetic properties and applications is still limited. Herein, graphdiyne oxide quantum dots (GDYO QDs) have been synthesized through oxidative cleavage, which exhibit enhanced peroxidase-like activity with lower K_m and higher V_max than those of most carbon-based nanozymes. The catalytic mechanism is explored, showing that the enhanced catalytic performance is attributed to the good conjugated structure, large number of oxygen-containing groups, and small-sized nanosheets with few layers. As a kind of peroxidase mimetic, the GDY-based nanozyme has excellent potential in sensing H₂O₂ and biological antioxidants through the colorimetric assay, with a linear range from 5 to 500 μM and detection limit of 1.5 μM for H₂O₂ and a linear range from 0 to 90 μM and detection limit of 0.48 μM for l-cysteine. Our work will be beneficial to develop high-performance artificial enzymes and to understand their mechanism for better applications.

CunO/Au heterostructure dendrimer anchored on Cu foam as dual functional catalytic nanozyme for glucose sensing by enzyme mimic cascade reaction

Multifunctional catalytic performance plays a crucial role in bio-applications through the diversity and durability of artificial nanozymes. An effective synergy with sufficient accessible active sites and high specific surface area is a challenge for composite catalysts, especially to avoid uncontrollable aggregation and structural instability. Here, we fabricated a Cu_nO/Au heterostructure dendrimer on copper foam (Cu_nO/Au HD/CF) as dual functional catalytic nanozyme to achieve enzyme mimic cascade reactions for efficient colorimetric analysis. A highly porous CF skeleton-based CuO nanowire array (CuO NWA) with a large specific surface area supported an efficient load capacity to assemble sufficient Cu_nO/Au HD by electrodeposition. The bimetallic Au-Cu nanozyme successfully achieved an oxidase-like and peroxidase-like cascade catalysis by a target-responsive sensing mechanism. Due to the confirmed catalytic performance of selectivity, anti-interference ability, and reproducibility, a Cu_nO/Au HD/CF-based quantitative analytical method was developed for glucose detection with a wide linear range and considerable detection limit of 8.4 μM. The robust nonenzymatic catalytic strategy for colorimetric detection not only confirmed the dual functional catalytic activity of Cu_nO/Au HD/CF, but also showed great potential for applications in clinical diagnostics and biochemical analysis.