Magnetic Actuation of Smooth Muscle Cells Loaded with Superparamagnetic Iron Oxide Nanoparticles

Faecal incontinence (FI) is a debilitating disorder that affects a significant portion of the population. The research included in this thesis aimed to test the hypothesis that magnetic actuating of smooth muscle cells loaded with superparamagnetic iron oxide nanoparticles (SPION) can modify the cell phenotype, which could be used with as a future therapy. The research focused on exploring a novel method of magnetic actuation and assessing its effects on the phenotype and biocompatibility of human rectal smooth muscle cells (HRSMC). A 2D model was used to demonstrate the effects of SPION on HRSMC. Initially, the effect of incubating HRSMC with different concentrations of SPION (0, 31.25, 250 and 1000 μg/ml) for 24 hours was investigated. Transmission electron microscopy revealed that SPION were endocytosed by cells and became concentrated inside endosomes. Superconducting quantum interference device (SQUID) measurements showed that SPION loading was concentration dependent and also that saturation occurred for concentrations above 250 μg/ml. SPION loading of HRSMC led to inhibition of the gene expression of actin and calponin when incubated in differentiation medium, with or without magnetic actuation, suggesting SPION caused the cells to shift towards a more proliferative phenotype. Live cell imaging revealed actuation of SPION-loaded HRSMC with stronger magnets led to an observable movement of internalized SPION and the plasma membrane. The findings from this research indicate SPION is biocompatible and may alter the phenotype of HRSMC. Therefore, SPION may offer novel benefits for regenerating damaged muscle in the treatment of FI. Further investigation is needed to assess the effects of magnetic actuation on SPION loaded cells

Novel applications of biomaterials in the management of parastomal hernia and anal fistula

MD (res)The aim of this thesis was to explore novel applications for both traditional and contemporary biomaterials in the management of parastomal hernia and anal fistula. Parastomal hernias can be prevented or repaired using synthetic mesh; however, reported complications include infection, fibrosis and potential bowel erosion. The prophylactic role of a cross-linked collagen implant was assessed in terms of safety, feasibility and potential efficacy. Additionally, the human host response to this implant was evaluated. There were no complications related to infection or the implant‟s proximity to the bowel. The implant had excellent biocompatibility and resistance to degradation in most patients, and although fibrovascular in-growth and ECM deposition were limited, it seems to have excellent potential for soft tissue reinforcement and, more specifically, prevention of parastomal hernias. Anal fistulas are in the main successfully treated by surgical fistulotomy, however damage to the anal sphincter complex and subsequent incontinence have led to the development of other techniques which aim to either lessen or avoid such disturbance. One strategy involves the traditional cutting seton, and a modification of this technique, the „snug‟ silastic seton was assessed. In the short-medium term, this modification was demonstrated to be an effective addition to the fistula surgeon‟s armamentarium, although minor incontinence remained a concern. Other approaches employing contemporary biomaterials, fibrin glue and porcine intestinal submucosa, are aimed at tissue repair, rather than minimizing destruction. Their success rates however are highly variable. A pilot study aiming to assess the safety and potential efficacy of an 4 alternative biomaterial, cross-linked collagen in two different physical formats, was presented. In the short-medium term, both formats were shown to be safe, and equally effective. The results justify continued research into the use of biologically derived materials to heal anal fistulas. In conclusion, although disparate pathologies were addressed, both they and the thesis are unified by demonstrating that an understanding of the specific disease pathology, wound healing, and the host response to materials (synthetic and biological) are central to their successful management

Design and Testing Novel Wearable Instrumentation for Assessing Pelvic Floor Function and Exploring Continence Mechanisms

Urinary incontinence (UI) and fecal incontinence (FI) affect 20% of North Americans, with a higher prevalence in women and the elderly. The prevention and treatment of these conditions unfortunately leaves much to be desired, despite the $88B and$49B annual U.S. costs associated with managing UI and FI, respectively. Recent research suggests that the major problem lies with the sphincters themselves, rather than other structures. More needs to be learned about how age, injury and disease affect these sphincters. The literature is reviewed in Chapter 1, knowledge gaps are identified and testable hypotheses formulated. In Chapter 2, we describe the first subject-specific, 3-D, biomechanics model of the urethra capable of contracting the three individual muscle layers along their lines of action. This was developed to better understand how the different layers contribute to urethral closure during activities of daily living. Exploratory studies of the vascular plexus suggest a role in affecting functional urethral length. While this model helps one to understand which muscles contribute to continence, it could not provide insights into the amount of urine leaked which, after all, is what bothers women the most. In Chapter 3, we describe a novel approach for quantifying urine leakage both in and out of the clinic. While one can presently obtain micturition flowmetry in the seated posture in the clinic, this precludes the possibility of any information being gathered on leakage during activities of daily living (ADL). Instead, a patient must keep a leakage diary for several days, which unfortunately is prone to recall bias and other errors. Therefore, a novel wearable personal uroflowmeter (PUF) was invented and developed to attach over the urethral meatus in women to collect urine flow rate and leakage data during ADL leakage episodes. This was connected with a waist-mounted inertial measurement unit (IMU) to provide data on the pose and ADL associated with the volume of each leakage episode. Chapter 4 describes the first-in-human testing of the PUF in women in and outside the clinic, demonstrating the feasibility of wearable uroflowmetry. Moreover, theoretical studies of labia majora coaptation suggest that the labia can inadvertently form a potential reservoir for urine leakage during a sneeze or cough. This insight will help eliminate the confusion over the relationship between the ADL causing the passage of urine through the urethra (i.e., a cough) and that which later causes urine to leak from the labial reservoir (i.e., rising from a chair). A few incidents of this phenomenon were measured for the first time while testing the PUF in women. In terms of anorectal function, Chapter 5 reports the design and development of a disposable point-of-service instrumented anorectal manometry glove (“digital manometry”, DM) for testing anal sphincter and anorectal function at an order of magnitude lower cost than the standard high resolution anorectal manometry (HR-ARM). Chapter 6 reports first-in-human testing of the DM device in patients with and without FI and chronic constipation. Comparisons of the DM and HR-ARM results show reasonable agreement. In addition, the DM also provided myoelectric information useful for identifying paradoxical contraction of the anorectal muscle in patients with dyssynergic defecation. In summary, the dissertation provides novel and inexpensive approaches for a clinician or researcher to better document and understand incontinence.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163121/1/attari_1.pd

Continence technologies whitepaper: Informing new engineering science research

Advances in healthcare technology for continence have historically been limited compared to other areas of medicine, reflecting the complexities of the condition and social stigma which act as a barrier to participation. This whitepaper has been developed to inspire and direct the engineering science community towards research opportunities that exist for continence technologies that address unmet needs in diagnosis, treatment and long-term management. Our aim is to pinpoint key challenges and highlight related research opportunities for novel technological advances. To do so, we draw on experience and expertise from academics, clinicians, patients and patient groups linked to continence healthcare. This is presented in four areas of consideration: the clinical pathway, patient perspective, research challenges and effective innovation. In each we introduce seminal research, background information and demonstrative case-studies, before discussing their relevance to engineering science researchers who are interested in approaching this overlooked but vital area of healthcare

A novel wearable electronic device for treating neurogenic detrusor overactivity by conditional neuromodulation

Urinary incontinence is the involuntary leakage of urine and affects one in twenty of the population across all ages leading to poor quality of life and can be very high cost to the nation. It is possible to reduce these costs by accurate diagnosis and appropriate management of the condition. Urinary incontinence is often associated with an overactive bladder or urethral sphincter weakness, or both as a result of interrupting the pathway to nervous communication between the brain and the bladder leading to uncoordinated activity in the lower urinary tract. Treatment options for overactive bladder include antimuscarinic drugs and implanted electrical stimulators. However these drugs have intolerable side effects, while implanting a stimulator is a surgical procedure which is associated with degree of risk and becomes ineffective due to habituation to the continuous stimulation. The aim of the research was to develop a novel wearable anal device designed to deliver conditional neuromodulation. The device detects the electromyography activity in the lower urinary tract, and provides the transrectal stimulation to the Pudendal nerve when required, in order to suppress the bladder contractions while contracting the urethral sphincters. The clinical study included designing and manufacturing patient compatible model and conducting a clinical study to measure the safety and the efficacy of the device. Electronics circuit design included amplifier, signal processing system and constant current stimulator based on the specification derived from the clinical study and finally focused on optimisation of the device electrodes for improving stimulating parameters

Development of Functional Bioengineered Muscle Models and a Novel Micro-Perfusion System.

Tissue engineering combines the principles of medical, life science, and engineering fields toward the development of biological substitutes to restore, maintain, or improve tissue function. Previous work has demonstrated the feasibility of bioengineering smooth muscle tissue in vitro; however the contractile properties of bioengineered smooth muscle tissue have not been evaluated. It is imperative that bioengineered tissues have a high degree of functional testing in order to evaluate tissue-specific function as well as suitability for future clinical applications. This research describes the development and functional testing of novel 3-dimensional bioengineered smooth muscle tissues in vitro and the development of a micro-perfusion system to support culture and enhance functionality of bioengineered tissues. All bioengineered tissue models described here were developed utilizing a fibrin biomaterial, which is well-suited for bioengineering contractile tissues. We developed ring-shaped models of rat sphincter and colonic smooth muscle tissue as well as a strip model of human aortic vascular smooth muscle tissue. Functional testing of the contractile properties of bioengineered muscle tissues was accomplished using a custom build force transducer. Bioengineered tissues exhibited striking tissue-specific functionality, which was similar to smooth muscle in vivo, including the generation of spontaneous basal tone and agonist-induced contraction and relaxation, which was calcium-dependent and calcium-independent (respectively). Finally, in order to support the increased metabolic demands of bioengineered tissues, we designed and fabricated a novel micro-perfusion system to promote delivery of a constant supply of oxygenated media to bioengineered tissues. We tested the compatibility of our micro-perfusion system with Bioengineered Heart Muscle (BEHM) and found that the system is capable of supporting viability (mitochondrial activity, total protein, total RNA) and maintaining contractile properties (twitch force, specific force, electrical pacing, and expression of contractile proteins) of bioengineered tissues. In addition, short-term exposure of BEHMs to micro-perfusion resulted in some functional improvement. This research specifically adds to the knowledge base of two critical areas in tissue engineering research: 1) the development of functional bioengineered models, and 2) ancillary technology to support these models. Collectively, this research bridges several scientific and technological gaps in the field of functional tissue engineering.Ph.D.Applied PhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/58465/1/lhecker_1.pd

Qualitative assessment of smooth muscle cells propagated on 2D-and 3D-polycaprolactone polymers via scanning electron microscope

Polycaprolactone (PCL) polymers which illustrate both biocompatibility and resorbability for replacement or bulking of damaged or diseased tissue are important in tissue engineering. Cytocompatibilty of these polymers was assessed on two-dimensional PCL disks and threedimensional PCL solid and PCL hollow microspheres using human uterine mixed leiomyosarcoma (SKUT-1) and hamster ductus deferens leiomyosarcoma (CRL-1701) cell lines. Possible PCL cytotoxicity and morphology were investigated in SKUT- and CRL-1701 cells. SKUT cells cultured in disk and microsphere extracts between 24 h and 5 day time periods displayed statistically increased metabolic activity, though activity decreased significantly on 1 month and 1 year extracts. However, the metabolic activity of CRL-1701 cells was similar to controls. Activity increased significantly on the 1 month extracts and decreased significantly on the 1 year extracts. Scanning electron microscopy illustrated increased cell density of cells attached to pre-conditioned disks. After 5 days, cells were spindle-shaped, following microspheres contours indicating high focal adhesion. Both cell lines migrated inside the hollow microspheres, indicating that they benefit from the sheltered environment. This in vitro study suggests that hollow microspheres allow for further cell expansion with a sheltered environment to protect cells from sheer stress experienced in vivo.The Biomaterials and Polymer Division from the Council of Scientific and Industrial Research (Pretoria, South Africa) and the Department of Physiology, University of Pretoria (Pretoria, South Africa).http://www.jstage.jst.go.jp/browse/biomedre