Integrated biosensors for cell culture monitoring

Biosensors for endogenous compounds, such as glucose and lactate, are applied to monitor cell cultures. Cells can be cultivated for several purposes, such as understanding and modeling some biological mechanisms, the development of new drugs and therapies, and in the field of regenerative medicine. We have realized a self-contained monitoring system with remote readout. Metabolite detection is based on oxidases immobilized onto carbon nanotubes. We calibrate the system for glucose and lactate detection in phosphate buffer solution. A hw/sw architecture records the signal generated by the biosensor and transmits it to a remote station by means of a Bluetooth module. We have validated 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.

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

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

P450-mediated electrochemical sensing of drugs in human plasma for personalized therapy

Sandro Carrara, Andrea Cavallini, Giovanni De Micheli

Nowadays, the concept of personalized therapy gains momentum. Pharmacogenomics, which represents a first answer to these needs, has the drawback of neglecting some variations of therapy response due to non-genetic factors. The aim of this paper is to investigate the feasibility of a non-genetic approach to personalized therapy, via the point-of-care drug monitoring in biological fluids with electrochemical biosensors. The proposed biosensor is based on the use of P450 enzymes as probe molecules, thanks to their key role in human metabolism. Multiwalled carbon nanotubes are used to enhance biosensor sensitivity. Results show how the proposed system is capable to detect drug amounts within the corresponding pharmacological ranges in human serum.

2010

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