The skin-implant interface of percutaneous devices is generally weak and can fail when excessive loading disrupts the sealing of the interface by dermal and epidermal cells and tissue. As such, the formation of a stable implant-skin junction is a major factor in determining percutaneous implant success. In this study, we used functionalized self-assembled monolayers (SAMs) with discrete surface properties as model systems to assess the effects of biomaterial surface properties on controlling fibronectin (FN) adsorption and keratinocyte spreading and adhesion. The surface properties investigated were charge (positive and negative) and wettability (hydrophobic and hydrophilic). Gold slides prepared with SAMs were incubated with FN overnight. The cell binding sites were quantified on each surface using an antibody that targets the synergy binding site of the cell binding domains (HFN7.1) and the topography of the FN on the surfaces was evaluated with atomic force microscopy. The topography data demonstrated that the availability of cell binding domains is dependent on surface-mediated FN binding orientation. Cell spreading was assessed using a lipid membrane stain, maleimide. The cells were imaged by fluorescence microscopy and the cell area calculated. The percentage of cell adhesion was determined using a centrifugal force assay. Both keratinocyte assays suggested that the charge of the surface was the prominent factor in determining cell function on the surface over the surface wettability. The findings of this study strongly suggest that a positively charged implant surface with a FN coating will enhance the strength of the cutaneous seal around percutaneous implants over an unmodified surface.

Peritoneal dialysis (PD) is a well-established modality of renal replacement therapy, which has as a principle for its proper function the guaranteed access to the peritoneal cavity. PD catheter implant technique should be safe, as well as provide minimal inconvenience to the patient, agility for the service, and few complications. At the University Hospital of Santa Maria (HUSM; Santa Maria, RS, Brazil), the catheters were inserted by laparotomy since the 1980s. It is been desired by the Nephrology department an alternative to facilitate the procedure, leading to greater agility and greater autonomy of the service. This study aimed to analyze the results obtained by professionals trained to implant peritoneal catheters with the Seldinger technique, recently implemented, and those obtained with the standard surgical technique. The samples were obtained from medical records of patients with endstage chronic kidney disease at the Nephrology department of HUSM with peritoneal dialysis indication (n=104). The demographic profile of the patients was evaluated, as well as the presence of infection and / or bleeding in the surgical wound, the first infusion and the 30-day functionality of the catheters, and the survival rate one and two years after implant. Data for each peritoneal catheter insertion mode were expressed as frequencies and then compared by chi-square, Fisher exact or Mann Whitey tests, with a 5% significance level. The profile of the two groups had similar characteristics in relation to gender, age, history of diabetes mellitus and arterial hypertension. The functionality of the implant at first infusion was also similar for both groups (83.9%for Seldinger vs. 79% for surgery). When evaluated the functionality in 30 days, the Seldinger technique demonstrated a higher success rate (76.7%) than the surgical technique (43.6%) (P-value=0,002). Regarding the presence of infection and / or bleeding in the outside wound, the percentage was similar for both groups (14.8% for Seldinger vs. 16.9% for surgical). The survival rate of the catheters at 1 and 2 years was also similar for both groups (37% and 14.8% for Seldinger, 23.7% and 20.6% for surgery, respectively). Given these results, it can be concluded that the implant of peritoneal catheters by Seldinger technique is a qualified alternative that allows greater agility to the service since it is an ambulatory procedure, can be performed by nephrologists and involves less patient management; having similar functionality to surgical implant according to the experience reported at HUSM. / A diálise peritoneal (DP) é uma modalidade bem estabelecida de terapia renal substitutiva, que tem como princípio para seu bom funcionamento a garantia de acesso à cavidade peritoneal. A técnica de implante do cateter de DP deve ser segura, além de proporcionar o mínimo de inconveniência para o paciente, agilidade para o serviço, e poucas complicações. No Hospital Universitário de Santa Maria (HUSM; Santa Maria, RS, Brasil) os cateteres foram implantados por laparotomia desde a década de 1980. É almejada pelo Serviço de Nefrologia uma alternativa que facilite o procedimento, levando a maior agilidade e autonomia do Serviço. O presente trabalho se propôs a analisar os resultados obtidos, por profissionais treinados para implante de cateter peritoneal com a técnica percutânea de Seldinger, recentemente implantada, e os resultados obtidos com a técnica padrão, a cirúrgica. As amostras foram obtidas de dados dos prontuários de pacientes entre os pacientes com insuficiência renal crônica terminal do Serviço de Nefrologia do HUSM com indicação de diálise peritoneal (n=104). Foi avaliado o perfil demográfico dos pacientes, assim como a presença de infecção e/ou sangramento na ferida operatória, a funcionalidade do cateter na primeira infusão e após30dias, além da taxa de sobrevivência em um e dois anos após o implante. Os dados obtidos em cada modalidade de implante de cateter peritoneal foram expressos em frequências e posteriormente comparados pelos testes Qui-Quadrado, Exato de Fischer ou Mann Whitey, com um nível de significância de 5%. O perfil dos dois grupos apresentou características semelhantes em relação ao gênero, idade, ocorrência de diabetes mellitus e hipertensão arterial. A funcionalidade do implante, na primeira infusão, também foi semelhante para os dois grupos (83,9% para Seldinger, 79% para cirúrgico). Quando avaliada a funcionalidade em 30 dias, a técnica de Seldinger mostrou um percentual de sucesso (76,7%) maior que a técnica cirúrgica (43,6%) (P-valor=0,002). Com relação à presença de infecção e/ou sangramento no orifício de saída, o percentual foi semelhante para os dois grupos (14,8% para Seldinger, 16,9% para cirúrgico). A taxa de sobrevivência dos cateteres em 1 e 2 anos também foi semelhante para os dois grupos (37% e 14,8% para Seldinger, 23,7% e 20,6% para cirúrgico, respectivamente). Diante dos resultados, pode-se concluir que o implante de cateter peritoneal pela técnica percutânea de Seldinger é uma alternativa qualificada que permite maior agilidade ao serviço já que o procedimento é ambulatorial, pode ser realizado por nefrologistas e implica em menor manejo do paciente; apresentando funcionalidade semelhante ao implante cirúrgico conforme a experiência relatada no HUSM.