Implantable Multi-panel Platform for Continuous Monitoring of Exogenous and Endogenous Metabolites for Applications in Personalized Medicine

Nowadays, scientific advances are leading to the discovery of newer, better, more targeted treatments that will improve the human health. However, despite the promising results and the major advantages in treatments offered to patients, these personalized medical treatments are limited to few cases. Translational medicine research with animals is needed to find innovative, safe and life-saving solutions for patients, especially in drug development. Although technological improvements may lead one day to the end of animal testing, today those strategies are not sufficient, due to the complexity of living organisms. The living conditions of these animals are of primary importance because high stress levels can affect the experimental results. In this respect, the monitoring of the animals in a small living space by means of a fully implantable device, can contribute to minimize the human intervention, increasing the comfort for the animals. The objective of this thesis is the design and characterization of a fully implantable biosensor array for the real-time detection of endogenous and exogenous metabolites, for the monitoring of small caged animals in drug development, and for future applications in personalized medicine. The fully implantable device consists of: a passive sensing platform consisting of an array of four independent electrochemical biosensors, together with a pH sensor and a temperature sensor for the optimization of the sensing performances in different physiological conditions; integrated circuits capable of performing multiple electrochemical measurements; a coil for remote powering of the integrated circuit and the short-range data transmission to an external device; a membrane packaging ensuring measurements with high signal-to-noise ratio, biocompatibility and selectivity against possible interfering molecules in biological fluids. ⢠In vitro monitoring of four anti-cancer drugs and an anti-inflammatory drug within the pharmacological ranges in undiluted human serum; ⢠Demonstration of the in vitro functionality of the complete system, showing that the external powering system correctly operate the device, and receive the data from the sensors; ⢠In vivo biocompatibility tests of the packaging, showing after 30 days a significant reduction of the inflammatory response in time, suggesting normal host recovery; ⢠In vivo continuous monitoring of an anti-inflammatory drug, demonstrating the proof of-concept of the system for future personalized medicine applications

Electrochemical Biochip for Applications to Wireless and Batteryless Monitoring of Free-Moving Mice

A multi-sensing platform for applications in wireless and batteryless monitoring of free-moving small animals is presented in this paper. The proposed platform hosts six sensors: four biosensors for sensing of both disease biomarkers and therapeutic compounds, and two further sensors (T and pH) for biosensor calibration. Electrodeposition of Multi-Walled Carbon Nanotubes (MWCNTs) and the subsequent functionalization with proper enzymes is used to assure sensitivity and specificity in electrochemical biosensing. The realized sensors are demonstrated to be capable of measuring several parameters: lactate with a sensitivity of 77±26 μA/mM· cm2 and a limit of detection (LOD) of 4±1 μM; glucose with a sensitivity of 63±15 μA/mM· cm2 and a LOD of 8±2 μM; Etoposide (a well known anti-cancer agent) with a sensitivity of 0.15±0.04 mA/mM· cm2 and a LOD of 4±1 μM; Open Circuit Potential (OCP) measurements are used on a Pt/IrOx junction to sense pH with a sensitivity of around -75±5 mV/pH; while a Pt resistive thermal device is used to measure physiological temperature-range with an average sensitivity of 0.108±0.001 kΩ/°C

A Linear Approach to Multi-Panel Sensing in Personalized Therapy for Cancer Treatment

In this paper, a new approach for evaluating the performance of a multi-panel biosensor using linear algebra is presented. With a system-level mathematical analysis based on graphs and linear algebra, we formulate a new approach for contributions decoupling in a multi-panel biochip for simulta- neous detection of anti-cancer drugs, avoiding redundancy and interaction between enzymes. Experimental results have been used to validate the model

Do Carbon Nanotubes Contribute to Electrochemical Biosensing?

Carbon nanotubes have been attracting a lot of interest as electron transfer mediators to enhance electrochemical biosensing. The main reason behind this is usually recognized in terms of augmented electrochemical active surface area. The aim of this paper is to review other phenomena that occur at the electrochemical interface. Three distinct features of these phenomena mainly appear in electrochemical biosensing. We have applied the Cottrell, Randle-Sevčick, and Nernst effects to address these features. By using these features, several electrochemical biosensing systems are investigated. The differences among the proposed systems are presented and analyzed in light of these effects. We finally demonstrate that carbon nanotubes may induce completely opposite effects when dealing with different biosensing systems. This paper also shows that even seemingly small differences (e.g., changing metabolite as detected by the same enzyme) might result in opposite effects on the same carbon nanotube based sensor. Nevertheless, it is shown that carbon nanotubes, in some cases, confirm their exceptional nature in enhancing the sensor performance by orders of magnitude. Sensitivity increases from 87 ± 62 to 3718 ± 73 nA/μM ×cm2 and detection limit decreases from 7.5 ± 5.3 to 0,084 ± 0.002 μM in case of cyclophosphamide detected by the cytochromes P450 3A4

Nano-Sensor and Circuit Design for Anti-Cancer Drug Detection

The development of new technologies to monitor drugs concentration directly in patient’s blood is absolutely required to succeed in personalized drug therapies. In this study, Etoposide - a well-known anti-cancer drug - has been chosen as model for cyclic voltammetry detection of drugs. Carbon nanotubes are chosen as electron-transfer mediators to enhance the system sensitivity. A very low frequency and low slope triangular-wave potential is required to acquire cyclic voltammograms. Cyclic voltammograms are definitely needed for a correct identification and quantification of the drug concentration in the patient serum. The aim of the paper is to investigate the feasibility of VLSI fully-integration of cyclic voltammetry measurements as a tool to develop a low-cost chip for drug monitoring in personalized therapy. A triangular wave generator CMOS circuit is proposed by using Direct Digital Synthesis (DDS) method. The circuit is implemented in 0.18 μm technology and it presents the possibility of changing the slope of the triangular voltage in a wide range of 10 to 100mV/s

Design, fabrication, and test of a sensor array for perspective biosensing in chronic pathologies

Biosensing for chronic pathologies requires the simultaneous monitoring of different parameters such as drug concentrations, inflammation status, temperature and pH. In this paper we discuss the design, fabrication and test of a sensor array hosting five biosensor platforms, a pH electrode and a temperature sensor. Different and reproducible nano-bio- functionalization can be obtained with high spatial resolution via selective electrodeposition of chitosan/MWCNT/enzyme solutions at the various electrodes. The array, completely fabricated with biocompatible materials, can be integrated with a CMOS integrated circuit and a remote powering coil for the realization of a fully implantable device

Integrated Biosensors for Personalized Medicine

Biosensors are heterogenous devices, incorporating biological struc- tures combined with electronics, optical or other readout systems. They have been developed for detecting different biomolecules and/or pathogens and represent a key technology for advanced and point- of-care diagnostics as well as patient monitoring. In this paper we present a systematic classification of biosensors described in litera- ture, particularly focusing on nanotechnology-based sensing. Then, we present our approach to develop electrochemical biosensors for measuring metabolites and anticancer drugs, based on a platform for multiple target detection. This platform is modular and achieves a clear separation between the chemical and the electrical compo- nents, thus easing design and manufacturing. It shows superior per- formance thanks to the excellent properties of electron transfer and selectivity showed by enzymes immobilized on carbon nanotubes

Fully Integrated Biochip Platforms for Advanced Healthcare

Recent advances in microelectronics and biosensors are enabling developments of innovative biochips for advanced healthcare by providing fully integrated platforms for continuous monitoring of a large set of human disease biomarkers. Continuous monitoring of several human metabolites can be addressed by using fully integrated and minimally invasive devices located in the sub-cutis, typically in the peritoneal region. This extends the techniques of continuous monitoring of glucose currently being pursued with diabetic patients. However, several issues have to be considered in order to succeed in developing fully integrated and minimally invasive implantable devices. These innovative devices require a high-degree of integration, minimal invasive surgery, long-term biocompatibility, security and privacy in data transmission, high reliability, high reproducibility, high specificity, low detection limit and high sensitivity. Recent advances in the field have already proposed possible solutions for several of these issues. The aim of the present paper is to present a broad spectrum of recent results and to propose future directions of development in order to obtain fully implantable systems for the continuous monitoring of the human metabolism in advanced healthcare applications

An Implantable Bio-Micro-system for Drug Monitoring

Multi-target and continuous monitoring by wireless implantable devices is of increasing interest for personalized therapy. In this work an implantable system is presented which is capable of measuring different drugs with Cyclic Voltammetry (CV) method. The wireless microsystem consists of four modules, namely (i) The inductive coil; (ii) Power management IC; (iii) Readout and control IC; (iv) Biosensor array. The power management IC provides 1.8 V with as high as 2 mW power for the readout IC. The configurable readout IC is able to control the biosensor array and measure the sensor current in CV method. CV experiments performed with this microsystem well agree with a commercial equipment for two well known anti-cancer drugs, Etoposide and Mitoxantrone, detection