Amino-Functionalized Ti₃C₂ MXene Quantum Dots as Photoluminescent Sensors for Diagnosing Histidine in Human Serum

Abstract

As an emerging zero-dimensional nanomaterial, MXene quantum dots (MQDs) have aroused the interest of researchers because of their unique physical and chemical characteristics. Here, a straightforward hydrothermal strategy was used to successfully produce the amino-functionalized Ti 3 C 2 MQDs. The functionalized Ti 3 C 2 MQDs exhibited bright blue fluorescence (FL), which was derived from its size effect and surface defects. In addition, Ni 2+ can bind to the amino groups on the surface of Ti 3 C 2 MQDs. The absorption of the excitation light by the light-absorbing substance causes nickel ions to effectively quench the photoluminescence of Ti 3 C 2 MQDs, which can be explained by the internal filter effect (IFE). At the same time, the strong affinity of histidine (His) for Ni 2+ , which is absorbed by His to form a stable complex, causes Ni 2+ to dissociate from the Ti 3 C 2 MQD surface and restore the FL. Thus, a fluorescent sensor for detecting the His content in serum was developed. Overall, this work provides a method for the detection of His and shows that the Ti 3 C 2 MQDs have great potential in biomedical and biosensing applications.

Smart MXene Quantum Dot-Based Nanosystems for Biomedical Applications

“…MXene-based QDs illustrated great potentials for enhancing the specificity and sensitivity of sensors deployed for detecting proteins, genes, and viral particles [ 11 ]. For instance, to identify the histidine in human serum, amino-functionalized Ti 3 C 2 MXene QDs with bright blue fluorescence and high bio-affinity were prepared [ 72 ]. Furthermore, biocompatible aerogels with good stability have been constructed from MXene QDs and watermelon peel by immersing freeze-dried fresh watermelon peel into the QD dispersion; these nanosystems demonstrated suitable functionality in biosensing appliances [ 73 ].…”

Quantum Dots Compete at the Acme of MXene Family for the Optimal Catalysis

“…MQDs have been applied to biomedical [ 129 , 130 ], optical device [ 131 – 133 ], energy storage [ 134 – 138 ], and sensor fields [ 112 , 139 , 140 ] due to that they possess the advantages of non-toxicity, metal conductivity, excellent chemical stability and low cost. Currently, the research of pure MQDs cannot meet the development needs of practical application.…”

“…Constructing surface defect is an effective strategy. Furthermore, studies have shown that the passivation of surface defects induced by amino groups facilitates to improve the PL properties of MQDs, resulting in bright blue fluorescence and enhanced fluorescence lifetime [ 140 ]. The doping includes both non-metallic elements such as N, P, and S, and transition metal elements such as Ni, Co, and Cu.…”

Low Temperature Step Annealing Synthesis of the Ti2AlN MAX Phase to Fabricate MXene Quantum Dots

“…The ternary MAX phase can be easily converted into two-dimensional (2D) layered MXene sheets using a simple wet chemical etching process [10] and can be further reduced to zero-dimensional MXene quantum dots (MQDs) [26]. Similar to 2D materials such as graphene [27] and transition metal dichalcogenide (TMD)-based quantum dots [28][29][30], MQDs have become a center of interest for many researchers because of their excellent properties, such as good light emission [31,32], selective metal ion sensing [33][34][35][36], nontoxicity [26,37,38], biocompatibility [26], hydrophilicity [35], and functionalization [39,40]. Owing to their interesting optical properties, they can be used as crucial materials in optical sensors [41,42], bio-imaging [34], optical modulator [43] etc.…”

“…Owing to their interesting optical properties, they can be used as crucial materials in optical sensors [41,42], bio-imaging [34], optical modulator [43] etc. Comparatively, carbide MQDs [44,45] derived from the MAX phase containing a carbide group such as V 2 AlC [46], Nb 2 AlC [33], and Ti 3 AlC 2 [39] have been studied more than nitride MQDs [10,26]; thus, the exploration and broad study of the properties and applications of nitride based MQDs are necessary.…”