<p><strong>A compatible interface between a biomedical material and host tissue is paramount to the continual function and life-span of medical devices that reside in the body. However, the unfavourable host response that ensues when foreign materials inhabit the body must be overcome for sophisticated medical devices, such as artificial organs and real-time biosensors, to be used clinically. My thesis research commenced with a search to find a pharmaceutical compound that could be incorporated into a medical device to suppress the accumulation of fibrous tissue. A prolyl hydroxylase inhibitor, a drug developed to inhibit collagen synthesis, was found to be effective at inhibiting collagen deposition within and on the outer surface of a poly(lactic-glycolic acid) disc, and also limited connective tissue ingrowth. Furthermore, the drug suppressed Scavenger Receptor A (SRA) expression on a macrophage-like cell culture, a receptor known to contain a collagenous domain. The latter finding prompted a review of the literature, upon which it was discovered that SRA mediates leukocyte adhesion and binding to an assortment of materials, such as silica, modified polystyrene, titanium, and iron(III) oxide. As a result, a series of studies were initiated to investigate whether leukocytes use SRA to detect a range of different biomedical materials. Consequently, we found that SRA contributes very little to leukocyte binding of two common medical polymers, polystyrene and poly(lactic-co-glycolic acid), but may interact with the materials to affect the cytokine profile in the local environment. In a subsequent study, SRA was found to be crucial to the leukocyte binding of polyanionic hydrogels. In summary, we have identified a unique pharmaceutical strategy for suppressing the accumulation of fibrous tissue on medical devices in vivo, and uncovered a mechanism of leukocyte stimulation in response to incubation with biomedical materials that the material science research community was not previously aware of. </strong></p> / Doctor of Philosophy (PhD)

As the survival rate increases, the importance of quality of life post-cancer is increasing. This, in conjunction with genetic screening, has increase the number of breast reconstructions 36%. The most common complication causing revision of reconstructive surgery is the formation of a dense scar capsule around the silicone implant called capsular contracture. Nearly all patients will experience this complication, though with different degrees of response, ranging from moderate scarring to major disfigurement and pain at the implant site. Presently, there is no way to predict the degree of contraction capsule formation that individual patients will suffer prospectively, nor is there clinical approach to preventing this complication. Patient information and tissue was collected in a uniform manner to address these lingering problems. Clinical data was used to construct a predictive model which can accurately predict capsular contracture severity in breast reconstruction patients. Histological analysis demonstrated differences in structure and cell composition between different capsule severities. Of particular note, a new region was described which could serve as the communication interface between innate immune cells and fibroblasts. RNA-seq analysis identified 1029 significantly dysregulated genes in severe capsules. Pathway enrichment was then performed which highlights IL4/13 signaling, extracellular matrix organization, antigen presentation, and interferon signaling as importantly dysregulated pathways. These RNA results were also compared to various clinical and histological measurements to evaluate novel correlations. PVT-1, a long non-coding RNA associated with cancer, was strongly correlated to capsules formed after cancer removal. This suggests cancerous transformations of cell types that remain after the tumor is removed. Furthermore, transgelin and caspase 7 correlated to myofibroblasts density, suggesting an abnormal fibroblasts that are resistant to cell death and may have enhanced contractile abilities. Capsule formation is a complex process however, with well controlled clinical models quantitative differences can be found. These results serve as stepping stone for the field to move beyond retrospective clinical trials and pursue treatments and preventative measures. / Ph. D. / As the survival rate increases, the importance of quality of life post-cancer is increasing. This, in conjunction with genetic screening, has increase the number of breast reconstructions 36%. The most common complication causing revision of reconstructive surgery is the formation of a dense scar capsule around the silicone implant called capsular contracture. Nearly all patients will experience this complication, though with different degrees of response, ranging from moderate scarring to major disfigurement and pain at the implant site. Presently, there is no way to predict the degree of contraction capsule formation that individual patients will suffer prospectively, nor is there clinical approach to preventing this complication. Patient information and tissue was collected in a uniform manner to address these lingering problems. Clinical data was used to construct a predictive model which can accurately predict capsular contracture severity in breast reconstruction patients. Histological analysis demonstrated differences in structure and cell composition between different capsule severities. Of particular note, a new region was described which could serve as the communication interface between innate immune cells and fibroblasts. RNA-seq analysis identified 1029 significantly dysregulated genes in severe capsules. Pathway enrichment was then performed which highlights IL4/13 signaling, extracellular matrix organization, antigen presentation, and interferon signaling as importantly dysregulated pathways. These RNA results were also compared to various clinical and histological measurements to evaluate novel correlations. PVT-1, a long non-coding RNA associated with cancer, was strongly correlated to capsules formed after cancer removal. This suggests cancerous transformations of cell types that remain after the tumor is removed. Furthermore, transgelin and caspase 7 correlated to myofibroblasts density, suggesting an abnormal fibroblasts that are resistant to cell death and may have enhanced contractile abilities. Capsule formation is a complex process however, with well controlled clinical models quantitative differences can be found. These results serve as stepping stone for the field to move beyond retrospective clinical trials and pursue treatments and preventative measures.

Made available in DSpace on 2016-08-19T18:15:54Z (GMT). No. of bitstreams: 1 Silvia Teresa Evangelista.pdf: 209991 bytes, checksum: 497a2c5c02aa5d734a85bd23ce11c2b1 (MD5) Previous issue date: 2007-09-24 / Airway aspiration of foreign body (FB) is a universal problem and an important cause of morbidity and mortality especially for children and the elderly. FB aspiration was evaluated in 72 children and teenagers varying from 7 months to 15 years of age who underwent rigid bronchoscopy at the CMUH (Children Maternal University Hospital), in São Luís-MA/ Brazil, for FB aspiration in the period from 1995 to 2005. For data collecting, an index card was filled out for each patient. Epi-info and Bio-estata programs were used for processing and statistical analysis. A major prevalence of FB aspiration from 1998 through 2001 was observed. Most patients were from the countryside (55.6%). The predominant age was the firsts three years of life (81.9%). The prevalence was greater among the male sex (63.9%). In 83.3% of the cases the initial diagnosis was FB aspiration. The elapsed time between the aspiration and the bronchoscopy was greater than 72h (52.8 %). The most frequent site was the right lung (38.9 %). The most common types of FB found were of organic nature (83.3 %). The most prevailing radiological finding was hypotransparence (56.9%). Bronchitis was the most frequently reported complication related to FB aspiration (45.9%), and glottis edema was a major complication upon bronchoscopy (47.6%), with no deaths reported in the studied group. It is concluded that bronchoscopy is a safe, highly sensible and efficient procedure for the diagnosis and treatment of FB aspiration, and that a late diagnosis suggests a need for better qualification of the health professionals. / A aspiração de corpo estranho (ACE) para via aérea é um problema universal e uma importante causa de morbidade e mortalidade, especialmente em crianças e idosos. Avaliou-se a aspiração de corpo estranho em 72 crianças na faixa etária de 7 meses a 15 anos submetidas à endoscopia respiratória no Hospital Universitário Materno Infantil (HUMI) por ACE, no período de 1995 a 2005, São Luís - Maranhão. Para cada paciente estudado foi preenchida uma ficha de coleta de dados. Utilizou-se os programas Epi- Info e BioEstata para o processamento e análise estatística. Observou-se uma maior prevalência de ACE nos anos de 1998 a 2001. A maior procedência foi das cidades do interior (55,6%). A idade predominante foi nos três primeiros anos de vida (81,9%). A prevalência foi maior no sexo masculino (63,9%). Em 83,3% dos casos, o diagnóstico inicial foi de ACE. O tempo decorrido entre a aspiração e o exame endoscópico foi maior que 72h (52,8%). A localização mais freqüente foi o pulmão direito (38,9%). O tipo de corpo estranho (CE) mais encontrado foi o orgânico (83,3%). O achado radiológico mais prevalente foi a hipotransparência (56,9%). A complicação mais freqüente relacionada ao CE foi a bronquite (45,9%) A complicação relacionada ao exame endoscópico mais freqüente foi o edema de glote (47,6%), não havendo óbitos. Concluiu-se que a endoscopia respiratória mostrou-se um procedimento seguro, eficaz e de alta sensibilidade no diagnóstico e tratamento do ACE e que a demora no seu diagnóstico sugere a necessidade de melhor qualificação dos profissionais de saúde.

Although medical devices and biomaterial implants are used clinically in a variety of applications, the process of implanting them damages local tissue and initiates a localized non-specific inflammatory response that is detrimental to device performance. Extensive research efforts have focused on developing material surface treatments and systems to deliver anti-inflammatory agents to abrogate such biomaterial-mediated inflammation, yet long-term use of these traditional materials in vivo is limited due to continued inflammation and fibrous encapsulation. This work aims to address these limitations by developing a versatile implant coating with non-fouling properties using a system based on hydrogel microparticles (i.e. microgels). The overall objective of this project was to evaluate host responses to these microgel coatings. Microgel particles were synthesized from poly(N-isopropyl acrylamide) cross-linked with poly(ethylene glycol)-diacrylate and were successfully deposited onto polymeric substrates using a simple and reproducible spin coating technique. We determined that microgel-coated samples adsorbed significantly lower levels of human fibrinogen than controls. Further characterization using an in vitro culture system demonstrated that microgel coatings significantly reduced the adhesion and spreading of murine macrophages and primary human blood-derived monocytes compared to controls. Materials were then evaluated for early cellular responses following implantation in the intraperitoneal cavity of mice to model acute inflammation. Analyses of explanted biomaterials using immunofluorescence staining techniques revealed that microgel-coated samples significantly reduced the density of surface-adherent cells. Additional analysis using flow cytometry revealed that microgel-coated samples exhibited significantly lower levels of pro-inflammatory cytokines in adherent leukocytes compared to controls, indicating that these coatings modulate cellular pro-inflammatory activities. Finally, we implanted samples subcutaneously in rats to determine the efficacy of microgel coatings at longer time points using an established model of chronic inflammation. Explants were processed histologically and stained for various markers. Importantly, staining demonstrated that the microgel coatings significantly reduced fibrous capsule thickness, the capsules appeared less compact and structurally ordered than controls, and also contained significantly fewer cells. Collectively, these results demonstrate that microgel particles can be applied as polymeric coatings to modulate inflammation and achieve more desirable host responses in vivo, with the potential to extend implant lifetime.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 298-310).

Em função de modificações no processo de criação em escala industrial, associado à expansão do setor avícola nas áreas de genética, nutrição e sanidade, as lesões cutâneas em frangos de corte vêm tornando-se cada vez mais importantes. Na atualidade, as principais doenças que afetam a pele de frangos são a celulite, a varíola aviária, o querato-acantoma (QA) ou carcinoma dérmico de células escamosas (CDCE) e as dermatites inespecíficas, estas últimas geralmente associadas a traumatismos. A classificação das doenças cutâneas é imprecisa, uma vez que os critérios de inspeção tendem a agrupar essas lesões cutâneas nas carcaças de frangos de corte em uma única categoria denominada de “dermatose”. As lesões ulcerativas na pele de frangos de corte são causas comuns de condenação total ou parcial de carcaças em matadouros-frigoríficos. O querato-acantoma é uma das causas mais frequentes dessas lesões, sendo de etiologia desconhecida. Por outro lado, lesões ulcerativas macroscopicamente semelhantes às do querato-acantoma e causadas por granulomas do tipo corpo estranho, possivelmente de origem vegetal, vêm sendo observadas em aves abatidas em alguns matadouros-frigoríficos no estado do Rio Grande do Sul (Brasil). Com base nessas premissas, o objetivo desse trabalho foi avaliar histologicamente e analisar os fatores epidemiológicos envolvidos no aparecimento das lesões ulcerativas cutâneas: querato-acantoma e dermatite granulomatosa por corpo estranho (DGCE) em frangos de corte abatidos em matadouros-frigoríficos sob inspeção federal e estadual. Foram analisadas 363 amostras com lesões ulcerativas, de um total de 1.373.989 aves visualizadas. Destas, 169 carcaças foram diagnosticadas como querato-acantoma, representando uma prevalência de 0,012% e 210 carcaças foram diagnosticadas como dermatite granulomatosa por corpo estranho, representando 0,015%, A prevalência encontrada no presente trabalho para QA é similar aos valores encontrados por autores, já a prevalência encontrada para DGCE foi superior à relatada em 2004. Se verificou uma maior prevalência de QA em frangos abatidos em matadouros-frigoríficos sob inspeção federal e mais casos de DGCE nos abatidos em matadouros-frigoríficos sob inspeção estadual. A localização mais frequente das úlceras foi o dorso para o querato-acantoma e o peito para a DGCE. As lesões ulcerativas disseminadas na carcaça foram 100 % diagnosticadas como querato-acantoma. Macroscopicamente as lesões únicas podem ser tanto diagnósticas para querato-acantoma como dermatite granulomatosa por corpo estranho, sendo necessário o exame histopatológico para o diagnóstico definitivo. Houve grande variabilidade dos fatores epidemiológicos envolvidos no aparecimento de lesões ulcerativas de pele, indicando necessidade de novas análises para aumentar a amostragem das amostras. / Due to changes in the husbandry process on an industrial scale, associated with the expansion of the poultry sector in the areas of genetics, nutrition and health, the skin lesions have become increasingly important. At present, the major diseases that affect the skin in broilers are cellulite, fowl pox, the keratoacantoma (KA) or dermal squamous cell carcinoma (DSCC) and nonspecific dermatitis, the latter generally associated with trauma. The classification of skin diseases is inaccurate, since the inspection tend to group these skin lesions in carcasses of broilers in a single category called "dermatosis". The ulcerative skin lesions of broilers are common causes of total or partial condemnation of carcasses in slaughterhouses. The keratoacantoma is one of the most frequent causes of these injuries, and of unknown etiology. On the other hand, ulcerative lesions macroscopically similar to the keratoacantoma and granulomas caused by foreign body, possibly of plant origin, has been observed in some birds slaughtered in slaughterhouse in Rio Grande do Sul (Brazil). Based on these premises, the aim of this study was to histologically evaluate and analyze the epidemiological factors involved in the appearance of ulcerative skin: keratoacantoma and foreign body granulomatous dermatitis (FBGD) in broilers slaughtered in slaughterhouses under federal and state inspection. 363 samples were analyzed with ulcerative lesions, a total of 1,373,989 poultry displayed. Of these, 169 carcasses were diagnosed as keratoacantoma, representing a prevalence of 0.012% and 210 carcasses were diagnosed as granulomatous dermatitis foreign body, representing 0.015%. The prevalence founded in the present work to KA is within the range found by authors in previous works, since the prevalence DSCC was higher than that reported in 2004. There was a higher prevalence of KA in slaughter plants under federal inspection and more cases of DSCC in slaughter plants under state inspection. The most frequent location of ulcers was the back and chest for keratoacantoma for DSCC. Ulcerative lesions disseminated in the housing 100% were diagnosed as keratoacanthoma. Grossly, the lesions can be both unique diagnostic for keratoacanthoma as granulomatous dermatitis, requiring histopathology for definitive diagnosis. With this work, it was concluded that new skin lesions should be analyzed, to increase the sampling of specimens, decreasing the variability among the predisposing skin lesions.

Em função de modificações no processo de criação em escala industrial, associado à expansão do setor avícola nas áreas de genética, nutrição e sanidade, as lesões cutâneas em frangos de corte vêm tornando-se cada vez mais importantes. Na atualidade, as principais doenças que afetam a pele de frangos são a celulite, a varíola aviária, o querato-acantoma (QA) ou carcinoma dérmico de células escamosas (CDCE) e as dermatites inespecíficas, estas últimas geralmente associadas a traumatismos. A classificação das doenças cutâneas é imprecisa, uma vez que os critérios de inspeção tendem a agrupar essas lesões cutâneas nas carcaças de frangos de corte em uma única categoria denominada de “dermatose”. As lesões ulcerativas na pele de frangos de corte são causas comuns de condenação total ou parcial de carcaças em matadouros-frigoríficos. O querato-acantoma é uma das causas mais frequentes dessas lesões, sendo de etiologia desconhecida. Por outro lado, lesões ulcerativas macroscopicamente semelhantes às do querato-acantoma e causadas por granulomas do tipo corpo estranho, possivelmente de origem vegetal, vêm sendo observadas em aves abatidas em alguns matadouros-frigoríficos no estado do Rio Grande do Sul (Brasil). Com base nessas premissas, o objetivo desse trabalho foi avaliar histologicamente e analisar os fatores epidemiológicos envolvidos no aparecimento das lesões ulcerativas cutâneas: querato-acantoma e dermatite granulomatosa por corpo estranho (DGCE) em frangos de corte abatidos em matadouros-frigoríficos sob inspeção federal e estadual. Foram analisadas 363 amostras com lesões ulcerativas, de um total de 1.373.989 aves visualizadas. Destas, 169 carcaças foram diagnosticadas como querato-acantoma, representando uma prevalência de 0,012% e 210 carcaças foram diagnosticadas como dermatite granulomatosa por corpo estranho, representando 0,015%, A prevalência encontrada no presente trabalho para QA é similar aos valores encontrados por autores, já a prevalência encontrada para DGCE foi superior à relatada em 2004. Se verificou uma maior prevalência de QA em frangos abatidos em matadouros-frigoríficos sob inspeção federal e mais casos de DGCE nos abatidos em matadouros-frigoríficos sob inspeção estadual. A localização mais frequente das úlceras foi o dorso para o querato-acantoma e o peito para a DGCE. As lesões ulcerativas disseminadas na carcaça foram 100 % diagnosticadas como querato-acantoma. Macroscopicamente as lesões únicas podem ser tanto diagnósticas para querato-acantoma como dermatite granulomatosa por corpo estranho, sendo necessário o exame histopatológico para o diagnóstico definitivo. Houve grande variabilidade dos fatores epidemiológicos envolvidos no aparecimento de lesões ulcerativas de pele, indicando necessidade de novas análises para aumentar a amostragem das amostras. / Due to changes in the husbandry process on an industrial scale, associated with the expansion of the poultry sector in the areas of genetics, nutrition and health, the skin lesions have become increasingly important. At present, the major diseases that affect the skin in broilers are cellulite, fowl pox, the keratoacantoma (KA) or dermal squamous cell carcinoma (DSCC) and nonspecific dermatitis, the latter generally associated with trauma. The classification of skin diseases is inaccurate, since the inspection tend to group these skin lesions in carcasses of broilers in a single category called "dermatosis". The ulcerative skin lesions of broilers are common causes of total or partial condemnation of carcasses in slaughterhouses. The keratoacantoma is one of the most frequent causes of these injuries, and of unknown etiology. On the other hand, ulcerative lesions macroscopically similar to the keratoacantoma and granulomas caused by foreign body, possibly of plant origin, has been observed in some birds slaughtered in slaughterhouse in Rio Grande do Sul (Brazil). Based on these premises, the aim of this study was to histologically evaluate and analyze the epidemiological factors involved in the appearance of ulcerative skin: keratoacantoma and foreign body granulomatous dermatitis (FBGD) in broilers slaughtered in slaughterhouses under federal and state inspection. 363 samples were analyzed with ulcerative lesions, a total of 1,373,989 poultry displayed. Of these, 169 carcasses were diagnosed as keratoacantoma, representing a prevalence of 0.012% and 210 carcasses were diagnosed as granulomatous dermatitis foreign body, representing 0.015%. The prevalence founded in the present work to KA is within the range found by authors in previous works, since the prevalence DSCC was higher than that reported in 2004. There was a higher prevalence of KA in slaughter plants under federal inspection and more cases of DSCC in slaughter plants under state inspection. The most frequent location of ulcers was the back and chest for keratoacantoma for DSCC. Ulcerative lesions disseminated in the housing 100% were diagnosed as keratoacanthoma. Grossly, the lesions can be both unique diagnostic for keratoacanthoma as granulomatous dermatitis, requiring histopathology for definitive diagnosis. With this work, it was concluded that new skin lesions should be analyzed, to increase the sampling of specimens, decreasing the variability among the predisposing skin lesions.

Em função de modificações no processo de criação em escala industrial, associado à expansão do setor avícola nas áreas de genética, nutrição e sanidade, as lesões cutâneas em frangos de corte vêm tornando-se cada vez mais importantes. Na atualidade, as principais doenças que afetam a pele de frangos são a celulite, a varíola aviária, o querato-acantoma (QA) ou carcinoma dérmico de células escamosas (CDCE) e as dermatites inespecíficas, estas últimas geralmente associadas a traumatismos. A classificação das doenças cutâneas é imprecisa, uma vez que os critérios de inspeção tendem a agrupar essas lesões cutâneas nas carcaças de frangos de corte em uma única categoria denominada de “dermatose”. As lesões ulcerativas na pele de frangos de corte são causas comuns de condenação total ou parcial de carcaças em matadouros-frigoríficos. O querato-acantoma é uma das causas mais frequentes dessas lesões, sendo de etiologia desconhecida. Por outro lado, lesões ulcerativas macroscopicamente semelhantes às do querato-acantoma e causadas por granulomas do tipo corpo estranho, possivelmente de origem vegetal, vêm sendo observadas em aves abatidas em alguns matadouros-frigoríficos no estado do Rio Grande do Sul (Brasil). Com base nessas premissas, o objetivo desse trabalho foi avaliar histologicamente e analisar os fatores epidemiológicos envolvidos no aparecimento das lesões ulcerativas cutâneas: querato-acantoma e dermatite granulomatosa por corpo estranho (DGCE) em frangos de corte abatidos em matadouros-frigoríficos sob inspeção federal e estadual. Foram analisadas 363 amostras com lesões ulcerativas, de um total de 1.373.989 aves visualizadas. Destas, 169 carcaças foram diagnosticadas como querato-acantoma, representando uma prevalência de 0,012% e 210 carcaças foram diagnosticadas como dermatite granulomatosa por corpo estranho, representando 0,015%, A prevalência encontrada no presente trabalho para QA é similar aos valores encontrados por autores, já a prevalência encontrada para DGCE foi superior à relatada em 2004. Se verificou uma maior prevalência de QA em frangos abatidos em matadouros-frigoríficos sob inspeção federal e mais casos de DGCE nos abatidos em matadouros-frigoríficos sob inspeção estadual. A localização mais frequente das úlceras foi o dorso para o querato-acantoma e o peito para a DGCE. As lesões ulcerativas disseminadas na carcaça foram 100 % diagnosticadas como querato-acantoma. Macroscopicamente as lesões únicas podem ser tanto diagnósticas para querato-acantoma como dermatite granulomatosa por corpo estranho, sendo necessário o exame histopatológico para o diagnóstico definitivo. Houve grande variabilidade dos fatores epidemiológicos envolvidos no aparecimento de lesões ulcerativas de pele, indicando necessidade de novas análises para aumentar a amostragem das amostras. / Due to changes in the husbandry process on an industrial scale, associated with the expansion of the poultry sector in the areas of genetics, nutrition and health, the skin lesions have become increasingly important. At present, the major diseases that affect the skin in broilers are cellulite, fowl pox, the keratoacantoma (KA) or dermal squamous cell carcinoma (DSCC) and nonspecific dermatitis, the latter generally associated with trauma. The classification of skin diseases is inaccurate, since the inspection tend to group these skin lesions in carcasses of broilers in a single category called "dermatosis". The ulcerative skin lesions of broilers are common causes of total or partial condemnation of carcasses in slaughterhouses. The keratoacantoma is one of the most frequent causes of these injuries, and of unknown etiology. On the other hand, ulcerative lesions macroscopically similar to the keratoacantoma and granulomas caused by foreign body, possibly of plant origin, has been observed in some birds slaughtered in slaughterhouse in Rio Grande do Sul (Brazil). Based on these premises, the aim of this study was to histologically evaluate and analyze the epidemiological factors involved in the appearance of ulcerative skin: keratoacantoma and foreign body granulomatous dermatitis (FBGD) in broilers slaughtered in slaughterhouses under federal and state inspection. 363 samples were analyzed with ulcerative lesions, a total of 1,373,989 poultry displayed. Of these, 169 carcasses were diagnosed as keratoacantoma, representing a prevalence of 0.012% and 210 carcasses were diagnosed as granulomatous dermatitis foreign body, representing 0.015%. The prevalence founded in the present work to KA is within the range found by authors in previous works, since the prevalence DSCC was higher than that reported in 2004. There was a higher prevalence of KA in slaughter plants under federal inspection and more cases of DSCC in slaughter plants under state inspection. The most frequent location of ulcers was the back and chest for keratoacantoma for DSCC. Ulcerative lesions disseminated in the housing 100% were diagnosed as keratoacanthoma. Grossly, the lesions can be both unique diagnostic for keratoacanthoma as granulomatous dermatitis, requiring histopathology for definitive diagnosis. With this work, it was concluded that new skin lesions should be analyzed, to increase the sampling of specimens, decreasing the variability among the predisposing skin lesions.

No description available.

Stable single-unit recordings from the nervous system using microelectrode arrays can have significant implications for the treatment of a wide variety of sensory and movement disorders. However, the long-term performance of the implanted neural electrodes is compromised by the formation of glial scar around these devices, which is a typical consequence of the inflammatory tissue reaction to implantation-induced injury in the CNS. The glial scar is inhibitory to neurons and forms a barrier between the electrode and neurons in the surrounding brain tissue. Therefore, to maintain long-term recording stability, reactive gliosis and other inflammatory processes around the electrode need to be minimized. This work has succeeded in the development of neural electrode coatings that are capable of sustained release of anti-inflammatory agents while not adversely affecting the electrical performance of the electrodes. The effects of coating methods, initial drug loadings on release kinetics were investigated to optimize the coatings. The physical properties of the coatings and the bioactivity of released anti-inflammatory agents were characterized. The effect of the coatings on the electrical property of the electrodes was tested. Two candidate anti-inflammatory agents were screened by evaluating their anti-inflammatory potency in vitro. Finally, neural electrodes coated with the anti-inflammatory coatings were implanted into rat brains to assess the anti-inflammatory potential of the coatings in vivo. This work represents a promising approach to attenuate astroglial scar around the implanted silicon neural electrodes, and may provide a promising strategy to improve the long-term recording stability of silicon neural electrodes.