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. 2025 Apr 16;25(8):2508.
doi: 10.3390/s25082508.

Copper Nanoclusters Anchored on Crumpled N-Doped MXene for Ultra-Sensitive Electrochemical Sensing

Hanxue Yang  1   2   3 , Chao Rong  1   2   3 , Shundong Ge  1   2   3 , Tao Wang  1   2   3 , Bowei Zhang  1   2   3 , Fu-Zhen Xuan  1   2   3
Affiliations

Copper Nanoclusters Anchored on Crumpled N-Doped MXene for Ultra-Sensitive Electrochemical Sensing

Hanxue Yang et al. Sensors (Basel). .

Abstract

Simultaneous detection of dopamine (DA) and uric acid (UA) is essential for diagnosing neurological and metabolic diseases but hindered by overlapping electrochemical signals. We present an ultrasensitive electrochemical sensor using copper nanoclusters anchored on nitrogen-doped crumpled Ti3C2Tx MXene (Cu-N/Ti3C2Tx). The engineered 3D crumpled architecture prevents MXene restacking, exposes active sites, and enhances ion transport, while Cu nanoclusters boost electrocatalytic activity via accelerated electron transfer. Structural analyses confirm uniform Cu dispersion (3.0 wt%), Ti-N bonding, and strain-induced wrinkles, synergistically improving conductivity. The sensor achieves exceptional sensitivity (1958.3 and 1152.7 μA·mM-1·cm-2 for DA/UA), ultralow detection limits (0.058 and 0.099 μM for DA/UA), rapid response (<1.5 s), and interference resistance (e.g., ascorbic acid). Differential pulse voltammetry enables independent linear detection ranges (DA: 2-60 μM; UA: 5-100 μM) in biofluids, with 94.4% stability retention over 7 days. The designed sensor exhibits excellent capabilities for DA and UA detection. This work provides a novel design strategy for developing high-performance electrochemical sensors.

Keywords: Cu nanoclusters; MXene; crumpled structure; dopamine; uric acid.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Schematic synthesis process and microstructure characterizations of Cu-N/Ti3C2Tx. (a) Schematic synthesis of Cu-N/Ti3C2Tx. (b) SEM image. (c) Atomic-resolution HAADF-STEM image (the red circles mark the Cu nanoclusters). (d) HAADF-STEM image and (e) EDS mapping images (Ti, purple; Cu, green; C, red; N, blue) of Cu-N/Ti3C2Tx.
Figure 2
Figure 2
XPS analysis results of Cu-N/Ti3C2Tx, N/Ti3C2Tx, and Cu-Ti3C2Tx. (a) XPS survey spectra of Cu-N/Ti3C2Tx, N/Ti3C2Tx, and Cu/Ti3C2Tx. (b) N 1s high-resolution XPS spectra. (c) C 1s high-resolution XPS spectra. (d) Ti 2p high-resolution XPS spectra. (e) Cu 2p high-resolution XPS spectra.
Figure 3
Figure 3
Electrochemical responses. CV curves of Cu-N/Ti3C2Tx, N/Ti3C2Tx, and Cu-Ti3C2Tx in 0.1 M KCl with (a) 5 mM [Fe(CN)6]3−/4−, and in PBS (pH = 7.4, 0.1 M) with (b) 0.5 mM DA, (c) 0.5 mM UA. (d) The Nyquist plots of EIS at Cu-N/Ti3C2Tx, N/Ti3C2Tx, and Cu-Ti3C2Tx in 0.1 M KCl with 5 mM [Fe(CN)6]3−/4− electrolyte.
Figure 4
Figure 4
Electrochemical sensing performance. (a) DPV curves for Cu-N/Ti3C2Tx at different concentrations of DA. (b) The linear relationship between the peak current responses and the DA concentration. (c) DPV curves for Cu-N/Ti3C2Tx at different concentrations of UA. (d) The linear relationship between the peak current responses and the UA concentration.
Figure 5
Figure 5
Response time, selectivity, repeatability, and stability of electrochemical sensing. Instantaneous response time of Cu-N/Ti3C2Tx to (a) DA and (b) UA. (c) DPV responses of Cu-N/Ti3C2Tx for DA, UA, and other interferences. (d) Influence of multiple interfering substances on the effects of simultaneous detection of 50 μM DA and UA. (e) Stability of Cu-N/Ti3C2Tx after 10 and 20 cycles of scanning in 0.1 mM DA and UA. (f) The oxidation peak current on the same Cu-N/Ti3C2Tx at 15 days of storage at room temperature.
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