Nanocomposite materials have provided a wide range of conductivity, sensitivity, selectivity and linear response for electrochemical biosensors. However, the detection of rare cells at single cell level requires a new class of nanocomposite-coated electrodes with exceptional sensitivity and specificity. We recently developed a construct of gold nanoparticle-grafted functionalized graphene and nanostructured polyaniline (PANI) for high-performance biosensing within a very wide linear response and selective performance. Further, replacing the expensive gold nanoparticles with low-cost silver nanoparticles as well as optimizing the nanocomposite synthesis and functionalization protocols on the electrode surface in this work enabled us to develop ultrasensitive nanocomposites for label-free detection of breast cancer cells. The sensor presented a fast response time of 30 min within a dynamic range of 10 − 5 × 10⁶ cells mL⁻¹ and with a detection limit of 2 cells mL⁻¹ for the detection of SK-BR3 breast cancer cell. The nano-biosensor, for the first time, demonstrated a high efficiency of > 90% for the label-free detection of cancer cells in whole blood sample without any need for sample preparation and cell staining. The results demonstrated that the optimized nanocomposite developed in this work is a promising nanomaterial for electrochemical biosensing and with the potential applications in electro-catalysis and super-capacitances.

纳米复合材料为电化学生物传感器提供了广泛的电导率，灵敏度，选择性和线性响应。然而，在单个细胞水平上检测稀有细胞需要具有超高灵敏度和特异性的新型纳米复合涂层电极。我们最近开发了金纳米粒子接枝的功能化石墨烯和纳米结构聚苯胺（PANI）的构建体，可在非常宽的线性响应和选择性性能范围内实现高性能生物传感。此外，在这项工作中，用低成本的银纳米颗粒代替了昂贵的金纳米颗粒，以及在电极表面上优化了纳米复合材料的合成和功能化方案，使我们能够开发出超灵敏的纳米复合材料，用于乳腺癌的无标记检测。^6个细胞mL ^-1，检测限为2个细胞mL ^-1，用于检测SK-BR3乳腺癌细胞。纳米生物传感器首次证明在不进行样品制备和细胞染色的情况下，无标记检测全血样品中的癌细胞的效率高达90％以上。结果表明，在这项工作中开发的优化的纳米复合材料是一种有前途的纳米材料，可用于电化学生物传感，并在电催化和超电容方面具有潜在的应用前景。