Environmental significance of wearable sensors based on MXene and graphene

Conductive layered materials such as MXenes (e.g., transition metal carbides, nitrides, and carbonitrides), graphene and their derivatives have attracted tremendous research interests in diverse fields of research for their unique structured merits and outstanding physical and chemical properties. Benefitting from their unique layered structures and fascinating multifunctional characteristic, MXenes and graphene serve as vital components in a variety of wearable devices. Especially, due to their large surface area and high electrocatalytic activity, these materials have also demonstrated great promise in biophysical and biochemical sensing systems. Following an introduction into the field, we summarize the recent progress in wearable sensors that can be accomplished by using layered materials, with a specific focus on kinematic, mechanical, thermal, pressure and strain sensors. A further large section underscores the recent progress in MXenes and graphene based wearable biochemical sensors including electrolyte monitoring, glucose monitoring, micro/mcromolecular organics metabolite, volatile gases monitoring and humidity sensors. The next section covers the sensing of small biomolecules serving as biomarkers, which are of great significance for early diagnosis and treatment of a spectrum of diseases. This review underscores the recent progress in wearable sensors to be used in different physiological and environmental signals. Finally, the review concludes with a debate on current challenges being faced and future perspectives.     

Current progresses in two-dimensional MXene-based framework: prospects from superficial synthesis to energy conversion and storage applications

MXenes are regarded as a type of two-dimensional (2D) inorganic material, mainly comprising a number of transition metal carbides, nitrides, or carbonitrides atomic planes. Nevertheless, the scientific community is continuously interested in exploring and structuring the engineered-based multifunctional material for numerous applications. The MXenes-based materials in this context, have emerged as highly active compounds owing to their superior surface area, substantial interlayer spacing, highly reactive surface-active sites and surface functional group, even though, recent studies have shown significant scientific and theoretical progress related to enormous prospects in MXenes, chemical nature, robust electrochemistry and high hydrophilicity of MXenes. The role of MXenes in all kinds of strategies is still in an upgrading phase for their further improvement, and is not sufficiently summarized in the literature now. To begin with this, herein, present review article is intended to critically discuss the diversity of MXenes with respect to different composition, formulation, plasmonic, complexation, and numerous geometric and morphological aspects, along with novel construction strategies to improve their surface characteristics in all aforesaid multidimensional applications. Following that, in terms of broadening the application, this review article is envisaged to endorse the use of MXenes and their hybrid configuration in a series of emerging environmental decontamination via adsorption, photodegradation, photocatalytic fuel production via hydrogen evolution, CO₂ reduction, electrocatalytic sensing, along with membrane distillation and energy storage. In addition, comprehensive information about existing obstacles and future perspectives have been addressed. Finally, an overview is succinctly summarized and discussed regarding the emerging prospects of MXenes for their potential uses in numerous research fields. At the end, it is anticipated that this review article will pave the way for the effective use of MXenes in different fields of environmental remediation, energy conversion, storage and biomedical applications as an innovative, reliable, and multifunctional material.     

气敏新材料MXenes在呼出气体传感器中的应用

电子鼻结合人工智能对呼出气进行检测、分析和识别已成为非侵入性医疗检测领域的研究热点。然而,目前已报道的气体传感材料尚不能同时满足高灵敏度、高选择性和稳定的室温检测,阻碍了气体传感器在医疗健康领域的应用及发展,寻找合适的传感材料具有重要的意义和挑战。新型二维层状纳米材料MXenes具有种类多、比表面积大、导电性能强、表面含有丰富的官能团以及能带宽度可调等优异性能,是高灵敏、低能耗气体传感器的明星候选材料。本综述针对MXenes基材料的特殊结构,总结梳理了MXenes基材料在气体传感中的最新研究成果,聚焦于MXenes材料的气体传感机理和改性方法,对MXenes材料用于气体传感依然存在的问题和挑战进行深入探讨。     

Electrochemical Sensors Based on Carbon Nanotubes

Carbon nanotubes are attractive new materials. It has been about a decade since carbon nanotubes were discovered. Carbon nanotubes have many outstanding properties and have many practical or potential applications. In this short review we introduce recent advances in carbon nanotubes as potential material for electrochemical sensors. The advantages of carbon nanotubes as sensors are discussed along with future prospects.     

Electrochemical biosensors based on Ti3C2Tx MXene: future perspectives for on-site analysis

MXenes are recently developed two-dimensional layered materials composed of early transition metal carbides and/or nitrides that provide unique characteristics for biosensor applications. This review presents the recent progress made on the usage and applications of MXenes in the field of electrochemical biosensors, including microfluidic biosensors and wearable microfluidic biosensors, and highlights the challenges with possible solutions and future needs. The multilayered configuration and high conductivity make these materials as an immobilization matrix for the biomolecule immobilization with activity retention and to be explored in the fabrication of electrochemical sensors, respectively. First, how the MXene nanocomposite as an electrode modifier affects the sensing performance of the electrochemical biosensors based on enzymes, aptamer/DNA, and immunoassays is well described. Second, recent developments in MXene nanocomposites as wearable biosensing platforms for the biomolecule detection are highlighted. This review pointed out the future concerns and directions for the use of MXene nanocomposites to fabricate advanced electrochemical biosensors with high sensitivity and selectivity. Specifically, possibilities for developing microfluidic electrochemical sensors and wearable electrochemical microfluidic sensors with integrated biomolecule detection are emphasized.     

MXenes在水系锌离子电池中的应用研究进展

水系锌离子电池(AZIBs)作为一种低成本、高安全的新兴且前景广阔的储能技术近年来备受关注。新型MXenes材料由于其独特的结构特征和物理化学性质,如易调节的二维结构、优异的导电性、化学组成多样和可控的表面化学特性,在AZIBs中表现出独特的应用优势。本文全面综述近年来MXenes在AZIBs中应用的研究进展,探讨MXenes应用于AZIBs正负极的结构设计及性能优化策略：在正极方面,MXenes可直接作为活性物质或活性物质前驱体、基体材料,以获得高活性、优异的循环寿命和倍率性能;在负极方面,MXenes可作为锌沉积的二维/三维载体、亲锌基体及锌金属界面保护层,以减缓电化学反应过程中锌金属的腐蚀和枝晶生长。此外,本文也对MXenes基材料在AZIBs中应用的发展方向进行展望。     

光控二芳烯化学传感器及其研究进展

有机光致变色材料由于在光学记忆及分子开关器件等领域具有潜在的应用价值而备受关注。在众多有机光致变色系统中,二芳烯类光致变色化合物具有热稳定性好、耐疲劳、响应速度快和灵敏度高等优点,在光电材料和生物医学领域具有广阔的应用前景。近年来,围绕二芳烯构建可调控光化学传感器已成为功能材料领域的一大研究热点。本文主要介绍以二芳烯作为光调控单元合成具有多重调控功能的化学传感器的研究进展,并展望了该领域的应用前景和研究方向。     

Atomic defects,functional groups and properties in Mxenes

MXenes,a new family of functional two-dimensional(2 D) materials,have shown great potential for an extensive variety of applications within the last decade.Atomic defects and functional groups in MXenes are known to have a tremendous influence on the functional properties.In this review,we focus on recent progress in the characterization of atomic defects and functional group chemistry in MXenes,and how to control them to directly influence various properties(e.g.,electron transport,Li⁺ adsorption,hydrogen evolution reaction(HER) activity,and magnetism) of 2 D MXenes materials.Dynamic structural transformations such as oxidation and growth induced by atomic defects in MXenes are also discussed.The review thus provides perspectives on property optimization through atomic defect engineering,and bottom-up synthesis methods based on defect-assisted homoepitaxial growth of MXenes.     

MXene fibers for electronic textiles: Progress and perspectives

The rapid evolution of portable and wearable electronic devices has fueled the development of smart functional textiles that are able to conduct electricity, sense body movements, or store energy. One main challenge inhibiting the further development of functional textile-based electronics is the lack of robust functional fibers with suitable electrical, electrochemical and sensing functionalities. MXenes, an emerging family of two-dimensional(2D) materials, have shown to be promising candidates...     

Topical advances in nanomaterials based electrochemical sensors for resorcinol detection

The ever-increasing environmental pollution is a severe threat to the ecosystem’s healthy sustainability, and therefore environmental monitoring of these pollutants has become a burning issue throughout the world. In recent years, cost-effective, selective, portable, sensitive, and rapid sensing devices must be developed in urgent need. Advancement in nanotechnology has urged the use of different types of nanomaterials as an excellent electrode material to amplify the electrochemical detection in terms of long-term stability and electrocatalytic activity of the electrochemical sensors in addition to fulfill the aforementioned desires. This review article intimates significant advancement in developing the enzymatic and non-enzymatic electrochemical sensors based on different nanomaterials for the detection of resorcinol (RS) in the absence or presence of other phenolic compounds. This also concludes the current associated challenges as well as future perspectives for the analysis of RS in the environment. There is plethora of reported articles on RS sensors, but this review mainly discusses the selective reports on the applications of RS sensors.     

Recent progress in MXenes incorporated into electrospun nanofibers for biomedical application: Study focusing from 2017 to 2022

After discovering a new class of two-dimensional (2D) material, i.e., MXene, a further new scope, came into existence for researchers. Due to their remarkable physical, chemical, and biological properties, MXenes find their role in almost every research discipline. They have been used in biosensors, bioimaging, tissue engineering, drug delivery systems, and other areas. The MXenes can be functionalized with a wide range of atoms/molecules, making them diverse materials. Therefore, the potential of using MXenes in nanofibers can be much more than expected. In this review, we will understand the structure, synthesis, and general properties of MXenes. We will explain using MXenes while encasing them into nanofibers, providing their specific properties. For instance, MXenes-incorporated nanofibers are used in biomedical applications, including soft and hard-tissue engineering and delivery of antimicrobials. Furthermore, MXenes, when incorporated into nanofibers, are used in promoting cellular differentiation, wound healing, and neural tissue restoration, which are briefly discussed in this communication.     

基于MXenes的功能纤维的制备及其在智能可穿戴领域的应用

在电子信息和物联网技术的推动下,人类对可穿戴电子器件和智能织物的需求愈发突出,功能纤维作为智能可穿戴设备的重要载体,近年来获得快速发展。功能纤维的性能很大程度上取决于纤维的基础构筑单元。过渡金属碳/氮化物(MXenes)作为一种新兴的二维材料,凭借其高电导率、优异的可加工性能、可调节的表面特性以及出色的机械强度等优点,受到了极大的关注,也逐渐成为构筑功能纤维的重要单元。本文将主要综述MXenes的湿化学、熔融盐、无氟试剂刻蚀等方法和力学、电学、光学和化学稳定性等性能,阐述基于该材料制备的功能纤维在传感、储能以及其他智能领域的应用,最后讨论了基于MXenes材料的功能纤维的未来应用前景和技术挑战。     

Aptamers as molecular recognition elements for electrical nanobiosensors

Recent advances in nanotechnology have enabled the development of nanoscale sensors that outperform conventional biosensors. This review summarizes the nanoscale biosensors that use aptamers as molecular recognition elements. The advantages of aptamers over antibodies as sensors are highlighted. These advantages are especially apparent with electrical sensors such as electrochemical sensors or those using field-effect transistors. Figure Feeling proteins with aptamer-functionalized carbon nanotubes     

Role of MXene surface terminations in electrochemical energy storage: A review

MXenes are a group of recently discovered 2D materials and have attracted extensive attention since their first report in 2011; they have shown excellent prospects for energy storage applications owing to their unique layered microstructure and tunable electrical properties. One major feature of MXenes is their tailorable surface terminations (e.g., −F, −O, −OH). Numerous studies have indicated that the composition of the surface terminations can significantly impact the electrochemical properties of MXenes. Nonetheless, the underlying mechanisms are still poorly understood, mainly because of the difficulties in quantitative analysis and characterization. This review summarizes the latest research progress on MXene terminations. First, a systematic introduction to the approaches for preparing MXenes is presented, which generally dominates the surface terminations. Then, theoretical and experimental efforts regarding the surface terminations are discussed, and the influence of surface terminations on the electronic and electrochemical properties of MXenes are generalized. Finally, we present the significance and research prospects of MXene terminations. We expect this review to encourage research on MXenes and provide guidance for usingthese materials for batteries and supercapacitors.     

MXenes复合材料的发展:界面调控及结构设计

MXenes作为一类新兴的二维材料, 因具有独特的亲水性、 优异的力学性能、 丰富的表面官能团、 高导电率、 光热以及光电效应等性能而成为研究热点, 广泛应用在电磁屏蔽、 电化学储能、 生物医药、 分离、 传感器和海水淡化等领域. 虽然MXenes具有这些优异的性能, 但是其存在的与疏水性高分子相容性差、 带负电的官能团阻碍电解质运输及易氧化等问题限制了其实际应用. 近年来, 通过对MXenes进行界面调控以解决其固有缺陷, 并在此基础上对MXenes进行针对性的结构设计以提升界面稳定性, 其性能得到了进一步提升. 本文对MXenes复合材料发展过程中在界面调控和结构设计方面的研究进展进行总结, 并重点介绍了MXenes的结构和性质及MXenes在复合材料中的界面调控手段, 对MXenes复合材料的结构设计进行了阐述, 并对MXenes复合材料的发展前景进行了展望.     

非贵金属助催化剂MXene在光催化领域应用的研究进展

环境友好型半导体光催化是当前最具前景的光催化技术之一,它不仅能够将太阳能转化为化学能以解决能源危机,还可以将污染物降解矿化从而解决环境问题.但是,传统的半导体光催化剂受限于光利用率低、光生载流子复合率高、稳定性较差等几个方面,无法达到理想的光催化效果.在半导体光催化剂上负载助催化剂是提升光催化效率的有效策略之一.负载助催化剂能够增强光生电荷在半导体与助催化剂界面间的传输,提供额外的催化活性位点,增强光捕获能力,因而被广泛应用于光催化剂的改性.目前广泛使用的贵金属助催化剂包括Au,Ag,Pt,Ru等,虽然这些贵金属助催化剂性能优异,但是它们存在储量少和成本高的问题,严重影响其规模化应用.因此,开展高效且成本低廉的非贵金属助催化剂的研究非常必要.近来,一种新型二维过渡金属材料(MXene)因其具有独特的二维层状结构、优异的导电性能、出色的光学和热力学性质而成为催化领域的研究热点.本文综述了有关非贵金属助催化剂MXene在光催化领域的最新研究进展,内容包括:(1)MXene材料的体相与表面结构特性;(2)薄层MXene的制备方法,例如氢氟酸刻蚀法、氢氟酸替代物刻蚀法以及熔融氟盐刻蚀法;(3)MXene基复合光催化剂的合成及改性策略,包括机械混合、自组装、原位氧化等;(4)MXene辅助增强光催化活性机理.论文还重点介绍了MXene作为助催化剂在光催化领域中的应用,包括光催化分解水产氢、光催化CO2还原、光催化固氮以及有机污染物的光催化降解.最后,论文分析了MXene基异质结光催化剂存在的问题与面临的挑战,并对MXene助催化剂的未来发展进行了展望.主要观点包括:(1)关于光催化分解水、空气净化、合成氨领域的研究较少,需要进一步开展;(2)MXene基异质结光催化剂的反应机理仍存在争议,需采用现代化仪器设备(包括原位表征技术)对其进行更为深入的探究;(3)目前,大多数MXene材料的制备都是通过强腐蚀性的氢氟酸或氢氟酸替代物刻蚀,开发环境友好且高效的MXene制备方法迫在眉睫;(4)阐明MXene表面终端基团的作用有助于提升MXene基复合光催化剂的性能;(5)引入新的改性策略如局域表面等离子体共振效应(LSPR)、缺陷调控、单原子催化(SAC)等来提高MXene基光催化剂的催化性能,是未来MXene基复合催化剂的发展方向.     

MXenes材料的光学特性及相关研究进展

过渡金属碳化物、 氮化物或碳氮化物(MXenes)具有丰富的元素组成和结构可调性, 显示出丰富的物理化学性质和巨大的应用潜力. 本文以此类材料的基本光学特性为基础, 从光子发射、 透明导电及储能、 非线性光学、 表面等离激元及拉曼增强、 光热转化、 光催化及光响应等光学相关领域展开分析和综述. 并对此二维材料相关应用的未来发展及机遇作了简单评述, 以期为进一步的研究提供参考.     

Recent Advances in Electrochemical Sensors Based on Molecularly Imprinted Polymers and Nanomaterials

This review focuses on the recent achievement during period of 2013–2018 related to the electrochemical sensors based on molecularly imprinted polymers (MIPs) combined with nanomaterials for various kinds of applications. MIPs based electrochemical sensors have found a great interest due to their high stability, short time required for electropolymerization, and high specificity towards the target analyte. The sensitivity is considered as one of the important parameter in electrochemical sensing strategies that should be improved by the combination of highly conductive nanomaterials with selective MIPs. In general, the most employed nanomaterials are magnetic nanoparticles, gold nanoparticles (AuNPs), carbon nanotubes and graphene. This review discusses the main current achievement as well as the current challenges regarding the development of biomimetic sensors in electroanalysis.     

Recent advances in MXenes-based glucose biosensors

It is established that monitoring blood glucose on a daily basis is one of the most effective solutions to prevent and treat diabetes. Consequently, developing a glucose sensing platform with outstanding sensing performance occupies an indispensable position for the early diagnosis and risk assessment of diabetes. Recently, biosensor has been deemed as a promising apparatus to acquire the signals for glucose monitoring based on 2D materials. However, it is unsatisfied to deploy some materials widely as a result of some inherent defects. Carbon nanotubes have comparatively high toxicity. MoS₂ with unfavourable biocompatibility are still arduously implemented on being functionalized. Fortunately, MXene, a brand-new and rapidly developing two-dimensional material, exhibits marvellous application potential in the domain of biosensing. Therefore, it has exerted tremendous attention from diverse scientific fields owning to its remarkable properties, such as excellent hydrophilicity, metal-like conductivity, abundant surface functional groups, unique layered structure, large specific surface area and remarkable biocompatibility. This review mainly focuses on the main synthetic route of MXenes, as well as the recent advancements of biosensors involving MXenes as an electrode modifier for glucose detection. In addition, the promising prospects and challenges of glucose sensing technology based on MXenes are also discussed.     

Functional One‐Dimensional Nanomaterials: Applications in Nanoscale Biosensors

Abstract

Nanostructures such as nanotubes (NTs), nanowires (NWs), and nanoparticles present new opportunities as sensing platforms for biological and environmental applications. Having micrometer‐scale lengths and nanometer‐scale diameters, NTs and NWs can be manipulated with current microfabrication, as well as self‐assembly techniques to fabricate nanoscale devices and sensors. Alignment, uniform dispersion, selective growth, and diameter control are parameters that are critical to the successful integration of nanostructures into sensors and devices. Overcoming these challenges should lead to sensors with better selectivity, sensitivity, and longer operational lifetime. This review discusses biosensors based on nanostructured material.