Biomedical integrated circuit design for an electro-therapy device : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Electronics and Computer Engineering (Bioelectronics) at School of Engineering and Advanced Technology, Massey University, Albany Campus, New Zealand

Journal articles in Appendix A removed for copyright reasons. Chapters 3, 4 and 5 published respectively as: Abbas Al-Darkazly, Ibtisam A., & Hasan, S. M. Rezaul. (2016). A waveform generator circuit for extra low‐frequency CMOS micro‐power applications, International Journal of Circuit Theory and Applications, 44, 266-279. https://doi-org.ezproxy.massey.ac.nz/10.1002/cta.2074 Abbas Al-Darkazly, Ibtisam A., & Hasan, S. M. Rezaul. (2016). Dual-band waveform generator with ultra-wide low-frequency tuning-range, IEEE Access, 4, 3169-3181. DOI: 10.1109/ACCESS.2016.2557843 Abbas Al-Darkazly, Ibtisam A., & Hasan, S. M. Rezaul. (2017). Optimized low-power CMOS active-electrode-pair for low-frequency multi-channel biomedical stimulation, Microelectronics Journal, 66, 18-24. https://doi-org.ezproxy.massey.ac.nz/10.1016/j.mejo.2017.05.014A biomedical integrated circuit design (IC) is utilized for the development of a novel non-invasive electro-therapy device, for low frequency multi-channel biomedical stimulation to transform immune activity and induce anti-viral state. Biomedical integrated circuit design is an important branch of modern electronic engineering that uses the application of electronic engineering principles for biomedical disciplines, to develop bioelectronics devices that are implanted within the body and for non-invasive devices to improve patient’s lives. These devices use the application of an electric field to stimulate reactions to restore normal cell functions and activate the cells to treat a variety of disorders or disease conditions. Bioelectronics devices can be designed for use as alternative treatments to overcome the deficiencies of several conventional medical treatments. It could potentially assist as drug-free relief when therapeutic drugs become ineffective, costly, with serious side effects and cannot be replaced, loss of future treatment options, and hence, life threatening, as for drug resistant Human immunodeficiency virus (HIV-1) patients. Since the underlying mechanisms of the biological system and disease state is dominated by electrostatic interactions, specifically, the interaction between HIV-1 and the host cell that is predominantly by electrostatic interactions (protein charge-charge interaction) has an important role in its life cycle replication. At given pulses, the charge distribution and polarization of the electro-active protein molecules takes place, inducing conformation change which can enhance immune activity and inhibit the interaction of HIV-1 and host cells, disturbing its life cycle, leading to the mechanisms of the inactivation signal-induced virus death. These electrically induced protein transformations is used in this research as blood-cell treatment and as anti-HIV-1 electrotherapy. Advances in bioelectronics technology, which involve new CMOS IC design, and in bio-electrochemistry science, which include cellular function, electro-active biomolecules and their responses, have contributed to this project to develop the concept of a novel electro-therapy device, for biomedical treatment applications. This involves understanding of the underlying mechanisms of the biological system and disease condition from an electronic engineer’s point of view as well as the interface between the electronic signal and the biological cells, and how electronic devices and circuitry directly communicate with the electro-active body tissue and blood cells. This research project addresses the design and development of a novel energy efficient miniature biomedical device using a new CMOS technology. It can generate, deliver and control an appropriate periodical low frequency electrical pulses, through the low-resistance skin surface to a patient’s blood. The notable feature of such a smart device is its cellular specificity: the parameters of the generated electrical pulse which are designed and selected in order to stimulate only one particular type of tissue (blood) leaving the others unaffected. The device comprises a mixed-signal low power dualband waveform generator (WFG) chip along with a novel two band tuning system. It was fabricated using Global Foundries (GF) 8RF-DM 130-nm CMOS process with a supply voltage of ±1V for the analog circuit and +1V for logic circuits. The WFG core (band I) can be tuned in the range 6.44 kHz - 1003 kHz through bias current adjustment, while a lower frequency (band II) in the range 0.1 Hz to 502 kHz can be provided digitally. Two WFG approaches, that comprise relaxation oscillators with different relaxation timing networks, have been developed for comparison. Since the aim of this work is to transfer electrical signal in a specifically controlled fashion through the tissue, a novel low power active electrode-pair signal delivery system, compatible with human skin with high signal integrity, is developed. The circuit was fabricated in a 130-nm CMOS process using a low supply-voltage of +1.2V to deliver bi-phase square waveform signals from 16 selectable low-frequency channels. The individual active electrode can also be used to deliver mono-phase square/triangular waveform output signals. Accuracy, safety, low power, light-weight, miniature and low-cost characteristics are the main concerns. Being a miniature bioelectronics component with low power consumption, the proposed device is suitable both as a non-invasive and as an implantable biomedical device, in which WFG and electrodes circuitry can communicate with the electro-active biomolecule, strongly stimulating certain events in a complex biological system. A theoretical analysis, experiment design and performance are carried out in invitro environments to examine the effect of the designed signal on human blood cellular proteins. Proteins that display a heterogeneous structure have various conductivities and permittivity (determining the interaction with the electrical field) and possess dielectric properties with a large conformation change, undergoing structural rearrangements in response to cellular signals. The frequency-dependent dielectric present in proteins involves the redistribution and alignment of the proteins charged molecule and its polar molecule in response to an applied external electrical field can also induce conformation change. Interference polarization within proteins could interrupt the interaction between both sides of predominantly host cell proteins and of the HIV-1 infective envelope and its protein particles. This could disturb the signalling proteins for cell activation, and, hence, the virus cannot conjugate with the target cells and control the host cell protein activity. Since the virus is unable to reproduce out of a host cell, hence the virus cannot mutate and develop resistance easily, and use alternative binding and entry mechanisms as in the pharmacological approaches. After carefully studying the interaction of the HIV-1 virus and the host cell, with respect to signal transfer, CD4 receptor, co-receptors CCR5 and nuclear transport factor nucleoporins FGNup153 proteins of the lymphatic system, which are essential targets for HIV-1 infection and its life cycle replication represent an attractive target to investigate in this research project. The activities of the underlying mechanism of the target cell are then examined utilizing immunofluorescence microscopy technique with specific fluorescent labelled antibodies, and accurate results are obtained with relatively low cost. The results demonstrated that the low frequency electrical pulse could inhibit virus attachment and fusion. It is also could provide a permeability barrier, that prevents the import and export of large macromolecule virus particles through the nuclear pore complex. These effects could induce an antiviral state for a period of time, and stope HIV-1 virus replication, with no potential risks and harm to the host cells, compared to the common drugs. This is promising for the conception of HIV-1 treatment in vivo. Although further investigations are required in order to fully use the application of electrical stimulation in vivo for treatment, the result is provides the necessary impetus for the applications of low frequency electrical stimulation on human immune response. This might offer important antiviral therapy against the most devastating pathogens in human history. This doctoral research is not only of academic interest but also highly relevant to medical applications. It is considered potentially beneficial in the development of knowledge in advanced technology for electro-medical treatment devices, their design, structure and applications to extend life, and for future growth in the biotechnology industry, therefore beneficial for the patients, physicians and for humanity

The role of modulation on the pyloric neurons and the neuromuscular junction in a pattern generator-effector system

Neuromodulation, the process of altering the electrical outputs of a neuron or neural circuit, allows an organism to control its physiological processes to meet the needs of both its internal and external environments. Previous work shows that the pyloric pattern of the kelp crab (Pugettia producta) stomatogastric nervous system (STNS) neurons responded to fewer neuromodulators than the Jonah crab (Cancer borealis). Since the kelp crab diet primarily eats kelp, it is possible that the movements of the foregut that control digestion may require less flexibility in functional output compared to an opportunistic feeder. To determine whether a reduced flexibility is correlated with diet, this study compared the modulatory responses in Pugettia to two other species of majoid crabs: Chionoecetes opilio and Libinia emarginata, which are both opportunistic feeders. Pooled data for this study found that Libinia and Chionoecetes responded to all twelve modulators tested. When considering the effect of modulators on stomatogastric ganglion (STG) motor outputs, we must consider whether these modulators also alter the excitatory junction potentials (EJPs) at the neuromuscular junction (NMJ), and whether there are differences in responses across species. To test this, the dorsal gastric nerve (dgn) was stimulated while recording intracellularly from the muscle fibers of the associated gm4 muscles. The NMJ of the gm4 in Cancer borealis did not appear to be broadly modulated, as only RPCH and CabTRP showed increases in amplitude, and RPCH decreased facilitation at 5 Hz

Determining the sites at which neuromodulators exert peripheral effects in the cardiac neuromuscular system of the American Lobster, \u3ci\u3eHomarus americanus\u3c/i\u3e

Networks of neurons known as central pattern generators (CPGs) generate rhythmic patterns of output to drive behaviors like locomotion. CPGs are relatively fixed networks that produce consistent patterns in the absence of other inputs. The heart contractions of the Homarus americanus are neurogenic and controlled by the CPG known as the cardiac ganglion. Neuromodulators can enable flexibility in CPG motor output, and also on muscle contractions by acting on the neuromuscular junction and the muscle itself. A tissue-specific transcriptome gleaned from the cardiac ganglion and cardiac muscle of the American lobster was used to predict the sites and sources of a variety of crustacean neuromodulators. If corresponding receptors were predicted to be expressed in the cardiac muscle, then it was hypothesized that the neuropeptide had peripheral effects. One peptide for which a cardiac muscle receptor was identified is myosuppressin. Myosuppressin has been shown to have modulatory effects at the cardiac neuromuscular system of the American lobster. In previous research, myosuppressin had modulatory effects on the periphery of cardiac neuromuscular system alone. It remains an open question of whether myosuppressin acts on the cardiac muscle directly, if it is exerting its effects at the neuromuscular junction (NMJ), or both. To test this, I performed physiological experiments on the isolated NMJ. Myosuppressin did not modulate the amplitude of the excitatory junction potentials. Since no modulatory effects were seen at the NMJ, the cardiac muscle was isolated from the cardiac ganglion and then glutamate-evoked contractions were stimulated. I showed that myosuppressin increased glutamate-evoked contraction amplitude. These data suggest myosuppressin exerts its peripheral effects at the cardiac muscle and not the NMJ

Rhythmic behaviors: Understanding neuromodulation at the neuromuscular level

Neuromodulation allows for the flexibility of neural circuit dynamics and the outputs they produce. Studies of the stomatogastric nervous system (STNS) have expanded our knowledge on the actions of neuromodulators, small molecules that most often activate G-protein coupled receptors and reconfigure circuit activity and composition. In these systems, modulation has been found to occur at every level, from sensory-motor coupling to neuromuscular transmission (Harris-Warrick and Marder 1991). Neuromodulators have complex effects on motor output; they can alter the firing of individual neurons while also modulating muscle properties, neuromuscular transmission, and sensory neuron response to muscle activity (Fort et al. 2004). We investigated this further by recording the motor output produced by the gastric mill rhythm of the lobster STNS under neuromodulator conditions. How is this neuromuscular system as a whole modulated to produce motor flexibility? We hypothesized that these neuromodulators act on individual receptors of component neurons of central pattern generator (CPG)-effector system themselves and at the periphery, coordinately altering muscle contraction by altering all levels of the crustacean neuromuscular system. Application of NRNFLRFamide, RPCH, oxotremorine, and proctolin to the gastric mill 4 (gm4) muscles of the Cancer crab showed that neuromodulators that have been found to have variable, yet significant effects on the activity of the neurons of the STNS directly alter the activity of the gm4 muscles as well, suggesting that coordination of peripheral actions and direct neuronal modulation regulates patterned motor output

Peripheral modulation of cardiac contractions in the American lobster, \u3ci\u3eHomarus americanus\u3c/i\u3e, by the peptide myosuppressin is mediated by effects on the cardiac muscle itself

A substantial factor for behavioral flexibility is modulation — largely via neuropeptides — which occurs at multiple sites including neurons, muscles, and the neuromuscular junction (NMJ). Complex modulation distributed across multiple sites provides an interesting question: does modulation at multiple locations lead to greater dynamics than one receptor site alone? The cardiac neuromuscular system of the American lobster (Homarus americanus), driven by a central pattern generator called the cardiac ganglion (CG), is a model system for peptide modulation. The peptide myosuppressin (pQDLDHVFLRFamide) has been shown in the whole heart to decrease contraction frequency, largely due to its effects on the CG, as well as increase contraction amplitude by acting on periphery of the neuromuscular system, either at the cardiac muscle, the NMJ, or both. This set of experiments addresses the location(s) at which myosuppressin exerts its effects at the periphery. To elucidate myosuppressin’s effects on the cardiac muscle, the CG was removed, and muscle contractions were stimulated with L-glutamate while superfusing myosuppressin. Myosuppressin increased glutamate-evoked contraction amplitude in the isolated muscle, suggesting that myosuppressin exerts its peripheral effects directly on the cardiac muscle. To examine effects on the NMJ, excitatory junction potentials were evoked by stimulating of the motor nerve and intracellularly recording a single muscle fiber both in control saline and in the presence of myosuppressin. Myosuppressin did not modulate the amplitude of EJPs suggesting myosuppressin acts at the muscle and not at the NMJ, to cause an increase in contraction amplitude

A low-noise, wide-band CMOS charge-sensitive preamplifier for use with a cadmium zinc telluride strip detector in a high-resolution small animal x-ray CT system

A low-noise, wide-band CMOS charge-sensitive preamplifier has been designed for use with a Cadmium Zinc Telluride (CZT) strip detector in the Oak Ridge NationalLaboratory\u27s (ORNL) MicroCAT small animal x-ray CT imaging system. The Characteristics of the CZT strip detector have been studied to optimize the design of the preamplifier, and are presented herein. The design of the charge-sensitive preamplifier(CSP) is discussed in detail, and test results are presented and discussed. The CSP was found to have a 10 - 90 % rise time of 23 ns, a charge gain of √ Hz x 1012 V/C, a dynamic range of + 0.9 V and - 2 V, and an equivalent input noise of 13 .nV√Hz 1 kHz and 2.2 nV 1 MHz. The CSP coupled to an Ortec 571 shaping amplifier has an Equivalent Noise Charge (ENC) minimum of 400 rms electrons for unipolar shaping at peaking time of 14 µs with a 4 pF detector capacitance. The system, with the same configuration, hasan ENC minimum of 550 rms electrons for bipolar shaping at the zero crossover of 15 µs.The prototype preamplifier has been fabricated in the AMI 1.2 µm process through the MOSIS microelectronics prototyping program

Molecular and mass spectral identification of the broadly conserved decapod crustacean neuropeptide pQIRYHQCYFNPISCF: The first PISCF-allatostatin (Manduca sexta- or C-type allatostatin) from a non-insect

The PISCF-allatostatins (Manduca sexta- or C-type allatostatins) are a family of pentadecapeptides characterized by a pyroglutamine blocked N-terminus, an unamidated-PISCF C-terminus, and a disulfide bridge between two internal Cys residues. Several isoforms of PISCF-AST are known, all from holometabolous insects. Using a combination of transcriptomics and mass spectrometry, we have identified the first PISCF-type peptides from a non-insect species. In silico analysis of crustacean ESTs identified several Litopenaeus vannamei (infraorder Penaeidea) transcripts encoding putative PISCF-AST precursors. Translation of these ESTs, with subsequent prediction of their putative post-translational processing, revealed the existence of as many as three PISCF-type peptides, including pQIRYHQCYFNPISCF (disulfide bridging between Cys7 and Cys14). Although none of the predicted isoforms was detected by mass spectrometry in L. vannamei, MALDI-FTMS mass profiling identified an m/z signal corresponding to pQIRYHQCYFNPISCF (disulfide bridge present) in neural tissue from 28 other decapods, which included members of six infraorders (Stenopodidea, Astacidea, Thalassinidea, Achelata, Anomura and Brachyura). Further characterization of the peptide using SORI-CID and chemical derivatization/enzymatic digestion supported the theorized structure. In both the crab Cancer borealis and the lobster Homarus americanus, MALDI-based tissue surveys suggest that pQIRYHQCYFNPISCF is broadly distributed in the nervous system; it was also detected in the posterior midgut caecum. Collectively, our data show that members of the PISCF-AST family are not restricted to the holometabolous insects, but instead may be broadly conserved within the Pancrustacea. Moreover, our data suggest that one highly conserved PISCF-type peptide, pQIRYHQCYFN-PISCF, is present in decapod crustaceans, functioning as a brain-gut paracrine/hormone. © 2009 Elsevier Inc. All rights reserved

Invertebrate neurophysiology - of currents, cells, and circuits

[no abstract