**8. GCN-β-CD/Au nanocomposite**

The GCN-β-CD/Au nanocomposite has been extensively investigated for its role in the detection of vitamin D. In a study [49], a label-free electrochemical sensor was developed based on a GCN-β-CD/Au nanocomposite modified GCE for sensitive and selective detection of vitamin D. The GCN-β-CD/Au nanocomposite was synthesized using a one-pot hydrothermal method and characterized by various techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), and


#### **Table 3.**

*Summary of the biosensors.*

Fourier transform infrared (FTIR) spectroscopy. The results indicated that the GCNβ-CD/Au nanocomposite exhibited excellent electrocatalytic activity and stability toward the oxidation of vitamin D.

Another study [104] reported the development of a simple and sensitive electrochemical sensor for the detection of vitamin D based on a GCN-β-CD/Au nanocomposite-modified GCE. The nanocomposite was synthesized by a simple *in situ* growth method and characterized by various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) [105]. The results indicated that the GCN-β-CD/Au nanocomposite exhibited good electrocatalytic activity and selectivity toward the oxidation of vitamin D.

Overall, these studies suggest that the GCN-β-CD/Au nanocomposite is a promising material for the development of electrochemical sensors for the detection of vitamin D. Its unique properties, such as excellent electrocatalytic activity and stability, make it an attractive candidate for the development of highly sensitive and selective vitamin D sensors (**Table 3**).
