Carbon Nanotubes-Based Electrochemical Sensing for Cell Culture Monitoring

Monitoring of metabolic compounds, such as glucose and lactate, is extensively reported in literature, especially for clinical purposes. Instead, the application of such technologies for monitoring metabolites in cell cultures has not been explored. From one side, such devices can provide information to the current state-of-the-art of cell lines, particularly those which are not fully known, as stem and embryonic cells. On the other hand, those systems can pave the way to fully automation for growing cell cultures, when coupled with robots for feeding. Among different presented strategies to develop biosensors,carbon nanotubes exhibit great properties, particularly suitable for biosensing. In this work nanostructured electrodes by using multi-walled carbon nanotubes are presented for the detection of glucose and lactate. Firstly, some results from simulations are illustrated in order to foresee the behavior of carbon nanotubes depending on their orientation, when they are dispersed onto the electrode surface. Then, such developed biosensors are characterized in terms of sensitivity and detection limit, and are compared to previously published results. Finally, monitoring of a cell culture is performed and the behavior of metabolites is analyzed as biosensors validation.

Amperometric biosensor with nanostructured electrodes by using multi-alled carbon nanotubes for glucose detection in cell culture medium

Cristina Boero, Sandro Carrara, Giovanni De Micheli

The monitoring of metabolic compounds such as glucose is largely reported in literature. The applications of this type of analysis are mainly related to clinical purposes, e.g. in diabetes pathology, where a lot of studies are presented in literature. Recently, some authors presented studies about glucose and lactate detection in cell culture monitoring [1], [2]. A clear identification of medium compounds could be interesting for biologists and biotechnologists, since they may be identified as markers of different cell states. It can also pave the way to automated systems, as a feedback of the medium state. In the field of amperometric biosensors, a lot of techniques related to the structuration of the electrodes have been presented in the last twenty years. Especially for glucose biosensors, a lot of mediators have been employed to carry the electrons released from the redox reaction to the surface of the electrode [3], [4]. Recently, some authors presented great results in terms of sensitivity and limit detection by using nanostructured electrodes. The employment of carbon nanotubes has shown promising results, due to their ability to promote the electron transfer from the active site of the enzyme onto the surface of the electrode, because of their electrocatalytic properties. Since we observed an improvement in terms of sensitivity and detection limit by using Multi-walled Carbon Nanotubes (MWCNT) for hydrogen peroxide (H2O2) detection, we decided to modify the nanostructured electrodes with glucose oxidase (GOD), since glucose is the most interesting compound in cell culture. We dropped 40 µl (1 mg ml-1) MWCNT onto Screen Printed Electrodes (SPE) purchased from Dropsens (Spain), and after, we deposited a certain quantity of GOD (3.5 U mm-2) and we stored the electrode overnight at +4°C. The result of the detection from chronoamperometry in stirring conditions with PBS as support electrolyte is shown in Figure 1.

2009

Highly Sensitive Carbon Nanotube-Based Sensing for Lactate and Glucose Monitoring in Cell Culture

Cristina Boero, Sandro Carrara, Giovanni De Micheli, Giovanna Del Vecchio

Monitoring of metabolic compounds in cell cultures can provide real-time information of cell line status. This is particularly important in those lines not fully known, as the case of embryonic and mesenchymal cells. On the other hand, such approach can pave the way to fully automated systems for growing cell cultures, when integrated in Petri dishes. To date, the main efforts emphasize the monitoring of few process variables, like pH, pO(2), electronic impedance, and temperature in bioreactors. Among different presented strategies to develop biosensors, carbon nanotubes exhibit great properties, particularly suitable for high-sensitive detection. In this work, nanostructured electrodes by using multiwalled carbon nanotubes are presented for the detection of lactate and glucose. Some results from simulations are illustrated in order to foresee the behavior of carbon nanotubes depending on their orientation, when they are randomly dispersed onto the electrode surface. A comparison between nonnanostructured and nanostructured electrodes is considered, showing that direct electron-transfer between the protein and the electrode is not possible without nanostructuration. Such developed biosensors are characterized in terms of sensitivity and detection limit, and are compared to previously published results. Lactate production is monitored in a cell culture by using the developed biosensor, and glucose detection is also performed to validate lactate behavior.

Institute of Electrical and Electronics Engineers2011

A Self-Contained System With CNTs-Based Biosensors for Cell Culture Monitoring

Cristina Boero, Sandro Carrara, Giovanni De Micheli, Jacopo Olivo

Biosensors have been applied to disparate fields, especially for endogenous compounds such as glucose and lactate. The main areas of application are certainly related to medical and diagnostic purposes. However, metabolic monitoring can be also of interest in cell analysis. Cells can be cultivated for several purposes, such as understanding and modeling some biological mechanisms, the development of new drugs and therapies, or in the field of regenerative medicine. All the aforementioned applications require a thorough knowledge of the biological system under study. In this paper, we propose the development of a self-contained system based on electrochemical biosensors for cell culture monitoring. The detection is based on oxidases immobilized onto carbon nanotubes. We also develop an architecture to record the signal generated by the biosensor and transmit it to a remote station by means of a Bluetooth module. We calibrate the system for glucose and lactate detection in phosphate buffer solution. We achieve a sensitivity of 55.5 µA/mMcm-2and a detection limit of 2 µM for glucose, as well as a sensitivity of 25.0 µA/mMcm-2 and a detection limit of 11 µM for lactate. We finally validate the two biosensors for metabolic monitoring in culture medium and we detect lactate production in neuroblastoma cells after 72 h of cultivation. The integrated system proposed in the present work opens new opportunities towards the development of novel tools for cell analysis.

2012

Amperometric biosensor with nanostructured electrodes by using multi-alled carbon nanotubes for glucose detection in cell culture medium

Cristina Boero, Sandro Carrara, Giovanni De Micheli

2009