Gold Nanoflowers Sensitivity and Selectivity Improvement by Thiolation to Detect Breast Cancer Volatile Organic...

Breast cancer is a malignant disease, and patient prognosis significantly improves when detected at an early stage. Therefore, various advanced chemiresistive sensors have been adopted to detect Volatile Organic Compounds (VOCs), which are byproducts of cellular metabolism exhaled in breath, for early breast cancer detection. In this work, gold nanoflowers (AuNFs) with a high surface area to volume ratio and a face centered cubic (FCC) crystalline structure of 203 $nm$ were synthesized, as confirmed by X-ray diffraction (XRD) and High resolution scanning electron microscopy (HRSEM). After dispersion in deionized (DI) water, the AuNFs were drop coated onto interdigital elliptical aluminum electrodes patterned on glass substrates, forming a continuous film (neighboring AuNFs closely packed) with an initial resistance of up to 2 $\mathit {K\Omega }$. The AuNFs films were then functionalized with phenylethyl mercaptan and 2-methyl-1-propanethiol using a simple and controllable drop coating method offering an advantage over conventional ligand ion exchange techniques. The large electrode spacing significantly reduces noise compared to traditional low spacing gold electrodes, which require costly photolithography. Furthermore, thiolation enhances both sensitivity and selectivity. The sensors exhibited very high sensitivity, attributed to the high conductivity of the AuNFs films and the sharp petal like active sites promoting strong VOC interactions. To the best of the authors' knowledge, this is the first report demonstrating high sensitivity for breast cancer related VOCs using aluminum electrodes on a glass substrate.