MF-RALU: design of an efficient multi-functional reversible arithmetic and logic unit for processor design on field programmable gate array platform

Most modern computer applications use reversible logic gates to solve power dissipation issues. This manuscript uses an efficient multi-functional reversible arithmetic and logical unit (MF-RALU) to perform 30 operations. The 32-bit MF-RALU includes arithmetic, logical, complement, shifters, multiplexers, different adders, and multipliers. The multi-bit reversible multiplexers are used to construct the MF-RALU structure. The Reduced instruction set computer (RISC) processor is designed to realize the functionality of the MF-RALU. The MF-RALU can perform its operation in a single clock cycle. The 1-bit RALU is developed and compared with existing approaches with improvements in performance metrics. The 32-bit reversible arithmetic units (RAUs) and reversible logical units (RLUs) are constructed using 1-bit RALU. The MF-RALU and RISC processor are synthesized individually in the Vivado environment using Verilog-HDL and implemented on Artix-7 field programmable gate array (FPGA). The MF-RALU utilizes a <11% chip area and consumes 332 mW total power. The RISC processor utilizes a <3% chip area and works at 483 MHZ frequency by consuming 159 mW of total power on Artix-7 FPGA

Organic and CMOS biosensors for detection of telomerase expression

Organic and CMOS biosensors for detection of telomerase expressio

Integrated Electronics for Molecular Biosensing

This thesis, Integrated electronics for molecular biosensing, focuses on different approaches to sense the presence and activity of a specific analyte by using integrated electronic platforms. The aim of the first platform is to detect the enzyme telomerase. Telomerase causes the elongation of telomeres, which are part of the chromosomes, and determines the lifespan of cells. Telomerase expression is a marker of malignity in tumoral cells and its evaluation can be exploited for early diagnosis of many types of cancer cells. To detect the telomerase enzyme, a CMOS (complementary metal-oxide semiconductor) biosensor based on CMFET (Charge-Modulated Field Effect Transistor) able to measure kinetics of DNA replication and telomerase reaction was developed. The sensor can be functionalized by immobilizing single strands of DNA that contain the telomeric sequence, used as probes. If telomerase is present, the probes will be elongated by the enzyme and the charge on the sensing area will change, which reflects in a variation of the output current or voltage. The chip includes three different readout schemes (voltage, current- and time-based), each of which has different measuring ranges and operating conditions. The measured data is then digitized, stored, and can be sent off-chip through SPI (Serial Peripheral Interface) protocol. A total of 1024 biosensors have been integrated in a single chip with a size of 10x10 mm2. Each sensor can be independently addressed and functionalized by an electrochemical procedure using an integrated potentiostat, thus requiring no external equipment. Although the sensors have been tailored and optimized to perform telomerase detection, the sensing areas can be functionalized to be used with different analytes. This feature turns the chip into a complete bioassay platform. The second part of this work rises from the idea that bacteria, like Escherichia coli, can detect analytes in solution even at extremely low concentrations and change their movement through a process called chemotaxis, to move towards chemical gradients in the solution. E. coli moves by rotating its flagella either clockwise (for random tumbles) or counterclockwise (for straight runs, when it senses a chemical it is attracted to). Therefore, observing bacteria flagellar rotation can give enough information on the presence of a specific analyte in the solution. To electronically detect bacteria movement, an active surface covered in electrodes has been designed. By measuring the impedance between each pair of electrodes through an integrated LIA (lock-in amplifier), it is possible to know how a single bacterium is moving. By that, the presence or absence of the analyte can be deduced, thus effectively turning bacteria into chemical sensors

Charge-Modulated Field-Effect Transistor: technologies and applications for biochemical sensing

The research activity described in the attached dissertation focused on the development, fabrication and characterization of field-effect transistor-based biochemical sensor (bioFET) developed in different technologies. Such a research field has been attracting a significant interest in the last decades, as electronic sensors can represent as valuable, portable and low cost alternative to the bulk, expensive laboratory instrumentation. Among the biochemical reactions, genetic processes have been thoroughly investigated in literature: in particular, DNA hybridization detection represents a basic biological reaction for several, more sophisticated analysis in medical, pharmaceutical and forensic fields. The development of the research activity was centered on a specific biosensor, namely Charge-Modulated Field-Effect Transistor (CMFET), originally proposed in 2005 by the Electronic Department at the University of Cagliari. In particular, the aim of the activity was to make a significant step forward with respect to the results already presented in literature for DNA hybridization detection, employing two different technologies: CMOS process and organic electronics. As regards CMOS process, the activity mainly focused on the testing of a Lab-on-a-Chip (LoC), hosting several CMFET structures, developed and fabricated before but never tested. The activity carried out allowed to develop a precise electrical model of the device, validated by actual measurements, by which the basic performances of the device were derived. Subsequently, the application of the LoC for DNA hybridization detection was demonstrated: a reliable biochemical protocol for the modification of the chip surface with DNA strands was developed, as well as a precise measurement procedure. A complete evaluation of the sensitivity and selectivity of the device with respect to DNA hybridization was obtained; from the obtained results, several consideration about the relationship between the chip layout and the performances of the device were inferred. In conclusion, a road-map for the development of a new chip, customized for the application as DNA hybridization sensor, was developed. As regards the Organic CMFET (OCMFET), the activity comprised design, fabrication and testing of devices particularly conceived as disposable DNA hybridization sensors for field-measurement kits. Such a task required the development of innovative technological processes for the fabrication of high-performances organic transistors, i.e. transistors capable to be operated at low voltages (about 1 V) with quasi-ideal electrical performances. In particular, a highly reliable fabrication process, compatible with plastic electronics and easily up-scalable to an industrial size, was determined. Consequently, novel OCMFET were fabricated and tested. World record results in terms of sensitivity and selectivity among the organic transistor-based DNA sensors were reproducibly obtained. Thanks to the reliability of the results, the performances of the OCMFET were carefully studied, and design rules for the optimization of the device were inferred; an optimized, low voltage OCMFET allowed to further enhance the result, determining final performances even better than the one of silicon-based sensors. Finally, thanks to an innovative analysis on the influence of the device polarization to the characteristics of the bioreceptor layer at a micro-nanometrical size, a physical effect related to a tilting of the DNA molecules with respect to the surface was observed. This feature, possibly related to the CMFET working principle, can allow to overcome a general limitation of the bioFET technologies that have limited so far the application of these devices in vivo, thus opening novel possible applications for the CMFET working principle beyond the measurements in vitr

Design and Implementation of an Integrated Biosensor Platform for Lab-on-a-Chip Diabetic Care Systems

Recent advances in semiconductor processing and microfabrication techniques allow the implementation of complex microstructures in a single platform or lab on chip. These devices require fewer samples, allow lightweight implementation, and offer high sensitivities. However, the use of these microstructures place stringent performance constraints on sensor readout architecture. In glucose sensing for diabetic patients, portable handheld devices are common, and have demonstrated significant performance improvement over the last decade. Fluctuations in glucose levels with patient physiological conditions are highly unpredictable and glucose monitors often require complex control algorithms along with dynamic physiological data. Recent research has focused on long term implantation of the sensor system. Glucose sensors combined with sensor readout, insulin bolus control algorithm, and insulin infusion devices can function as an artificial pancreas. However, challenges remain in integrated glucose sensing which include degradation of electrode sensitivity at the microscale, integration of the electrodes with low power low noise readout electronics, and correlation of fluctuations in glucose levels with other physiological data. This work develops 1) a low power and compact glucose monitoring system and 2) a low power single chip solution for real time physiological feedback in an artificial pancreas system. First, glucose sensor sensitivity and robustness is improved using robust vertically aligned carbon nanofiber (VACNF) microelectrodes. Electrode architectures have been optimized, modeled and verified with physiologically relevant glucose levels. Second, novel potentiostat topologies based on a difference-differential common gate input pair transimpedance amplifier and low-power voltage controlled oscillators have been proposed, mathematically modeled and implemented in a 0.18μm [micrometer] complementary metal oxide semiconductor (CMOS) process. Potentiostat circuits are widely used as the readout electronics in enzymatic electrochemical sensors. The integrated potentiostat with VACNF microelectrodes achieves competitive performance at low power and requires reduced chip space. Third, a low power instrumentation solution consisting of a programmable charge amplifier, an analog feature extractor and a control algorithm has been proposed and implemented to enable continuous physiological data extraction of bowel sounds using a single chip. Abdominal sounds can aid correlation of meal events to glucose levels. The developed integrated sensing systems represent a significant advancement in artificial pancreas systems

Bioelectronics for Amperometric Biosensors

The Discrete-to-Integrated Electronics group (D2In), at the University of Barcelona, in partnership with the Bioelectronics and Nanobioengineering Group (SICBIO), is researching Smart Self-Powered Bio-Electronic Systems. Our interest is focused on the development of custom built electronic solutions for bio-electronics applications, from discrete devices to Application-specific integrated circuit (ASIC) solutions. The integration of medical and electronic technologies allows the development of biomedical devices able to diagnose and/or treat pathologies by detecting and/or monitoring pathogens, multiple ions, PH changes, and so on. Currently this integration enables advances in various areas such as microelectronics, microfluidics, microsensors and bio-compatible materials which open the door to developing human body Lab-on-a-Chip implantable devices, Pointof- Care in vitro devices, etc. In this chapter the main attention is focused on the design of instrumentation related to amperometrics biosensor: biopotentiostat amplifiers and lock-in amplifiers. A potentiostat is a useful tool in many fields of investigation and industry performing electrochemical trials [1], so the quantity and variety of them is very extensive. Since they can be used in studies and targets as different as the study of chemical metal conversions [2] or carcinogenic cells detection, neuronal activity detection or Deoxyribonucleic acid (DNA) recognition, their characteristics are very varied..

Nonlinear Optical Responsive Molecular Switches

Nonlinear optical (NLO) materials have gained much attention during the last two decades owing to their potentiality in the field of optical data storage, optical information processing, optical switching, and telecommunication. NLO responsive macroscopic devices possess extensive applications in our day to day life. Such devices are considered as assemblies of several macroscopic components designed to achieve specific functions. The extension of this concept to the molecular level forms the basis of molecular devices. In this context, the design of NLO switches, that is, molecules characterized by their ability to alternate between two or more chemical forms displaying contrasts in one of their NLO properties, has motivated many experimental and theoretical works. Thus, this chapter focuses on the rational design of molecular NLO switches based on stimuli and materials with extensive examples reported in the literature. The factors affecting the efficiency of optical switches are discussed. The device fabrication of optical switches and their efficiency based on the optical switch, internal architecture, and substrate materials are described. In the end, applications of switches and future prospectus of designing new molecules with references are suitably discussed

MICROPARTICLE SAMPLING AND SEAPARATIONENABLED BY DROPLET MICROFLUIDICS

This work reports design, device fabrication, modeling and experimental results on newsampling and separation principles in which liquid is transported in a droplet form on a plannerhydrophobic surface with no moving parts. The presented particle sampler and separatorconstitute core units for the handheld lab-on-a-chip-based airborne particle monitoring system.For the airborne particle sampling, a novel method is developed by which the particles onthe solid surface are swept and sampled by electrowetting-actuated moving droplets. Theoreticalanalysis and experimental works along with microfabricated testing devices are carried out toinvestigate the underlying physics and to optimize the sampling conditions. The samplingconcepts are examined and proved on a solid surface and perforated filter membrane showinghigh sampling efficiencies.For the particle separation, a new separation scheme is developed in which the mixedparticles are separated within a mother droplet by traveling-wave dielectrophoresis (tw-DEP).Using the subsequent operation of droplet splitting by way of electrowetting, the separatedparticles can be isolated into each split droplet according to the DEP properties of the particles.This in-droplet separation is examined with many combinations of particles in microfabricateddevices. By investigating the particle behavior as function of the frequency of the traveling waveDEP signal, the separation efficiencies are optimized.The above microfluidic units constitute key components for upstream particle sampling anddownstream sample processing in the lab on a chip system, providing the following advantages:extremely small amount use of samples/reagents (2) no external pressure source required forfluidic operations, (3) simple design and fabrication since no mechanical moving structure