In vivo monitoring of reactive oxygen species (ROS) in tumors during treatment with anticancer therapy is important for understanding the mechanism of action and in the design of new anticancer drugs. In this work, a platinized nanoelectrode is placed into a single cell for detection of the ROS signal, and drug-induced ROS production is then recorded. The main advantages of this method are the short incubation time with the drug and its high sensitivity which allows the detection of low intracellular ROS concentrations. We have shown that our new method can measure the ROS response to chemotherapy in tumor-bearing mice in realtime. ROS levels were measured in vivo inside the tumor at different depths in response to doxorubicin. This work provides an effective new approach for the measurement of intracellular ROS by platinized nanoelectrodes.

Mechanical properties of living cells determined by cytoskeletal elements play a crucial role in a wide range of biological functions. However, low-stress mapping of mechanical properties with nanoscale resolution but...

The biodistribution of chemotherapy compounds within tumor tissue is one of the main challenges in the development of antineoplastic drugs, and techniques for simple, inexpensive, sensitive, and selective detection of various analytes in tumors are of great importance. In this paper we propose the use of platinized carbon nanoelectrodes (PtNEs) for the electrochemical detection of platinum-based drugs in various biological models, including single cells and tumor spheroids in vitro and inside solid tumors in vivo. We have demonstrated the quantitative direct detection of Pt(II) in breast adenocarcinoma MCF-7 cells treated with cisplatin and a cisplatin-based DNP prodrug. To realize the potential of this technique in advanced tumor models, we measured Pt(II) in 3D tumor spheroids in vitro and in tumor-bearing mice in vivo. The concentration gradient of Pt(II) species correlated with the distance from the sample surface in MCF-7 tumor spheroids. We then performed the detection of Pt(II) species in tumor-bearing mice treated intravenously with cisplatin and DNP. We found that there was deeper penetration of DNP in comparison to cisplatin. This research demonstrates a minimally invasive, real-time electrochemical technique for the study of platinum-based drugs.

The biodistribution of chemotherapy compounds within tumor tissue is one of the main challenges in the development of antineoplastic drugs, and novel techniques for simple, non-expensive, sensitive, and selective detection of various analytes in tumors are of great importance. In this paper we propose the use of platinized carbon nanoelectrodes (PtNE) for electrochemical detection of platinum-based drugs in various biological models, including single cells and tumor spheroids in vitro, and inside solid tumors in vivo. We have demonstrated quantitative direct detection of Pt(II) in breast adenocarcinoma MCF-7 cells treated with cisplatin and cisplatin-based DNP prodrug. To realize the potential of this technique in advanced tumor models, we measured Pt(II) in 3D tumor spheroids in vitro and tumor-bearing mice in vivo. The concentration gradient of Pt (II) species correlated with the distance from the sample surface in MCF-7 tumor spheroids. We then performed detection of Pt(II) species in tumor-bearing mice treated intravenously with cisplatin and DNP. We found that there was deeper penetration of DNP in comparison to cisplatin. This research demonstrates a novel minimally invasive, real-time electrochemical technique for the study of platinum-based drugs.

Alzheimers disease (AD) is the most common form of dementia, a progressive neurological disorder characterized by short and long-term memory loss, including cognitive and functional impairment, which is refractory to current therapy. It is suggested that the aggregation of β-amyloid peptide on neuronal cell surface leads to various deviations of its vital function due to myriad pathways defined by internalization of calcium ions, apoptosis promotion, reduction of membrane potential, synaptic activity loss etc. These are associated with structural reorganizations and pathologies of the cell cytoskeleton mainly involving actin filaments and microtubules, and consequently alterations of cell mechanical properties. Thus, the effect of amyloid oligomers on cells Youngs modulus has been observed in a variety of studies. However, the precise connection between the formation of amyloid aggregates on cell membranes and their effects on local mechanical properties of living cells is still unresolved. In this work, we have used correlative scanning ion-conductance microscopy (SICM) to study cell topography, Youngs modulus mapping and confocal imaging of Aβ aggregates formation on living cell surfaces with subsequent assessment of the reactive oxygen species levels inside single cells using platinum nanoelectrodes. We showed that correlative SICM technique, in conjunction with topography mapping and confocal imaging, can be used for Patch-Clamp recordings from living cells with evidently formed FAM-labeled Aβ aggregates on its surface. As we demonstrated, SICM can be successfully applied to studying cytotoxicity mechanisms of Aβ aggregates on living cell surface.