Graphene Biosensors for Diabetic Foot Ulcer Monitoring

• Autor(a) principal: Ornelas, Cristina Alejandra Paublini
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/153933
• topic: laser induced graphene; paper biosensor; thermoresistive; pH; diabetic foot ulcer; polyaniline; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

The prevalence of Diabetes Mellitus (DM) in the twenty-first century has increased drastically, consequently, the incidence of DM-related complications has increased as well. According to the International Diabetes Federation (IDF) in 2021, globally one in every ten adults aged from 20 to 79 years had DM. Approximately 15-34% of individuals with DM are likely to develop a Diabetic Foot Ulcer (DFU) throughout their lifetime. Unmonitored and in- fected DFU can lead to non-traumatic lower extremity amputation and worst-case cause morbidity. Therefore, it is of great importance to develop effective, rapid production, bio- compatible, low-cost, flexible, wearable, sustainable sensors to monitor objectively the ulcer healing state. This dissertation aims to meet this need through the development of tempera- ture and pH laser-induced graphene (LIG) sensors on paper, that could be included in smart bandages and medical wound dressings. During this dissertation, LIG on paper fabrication parameters were studied to obtain the most reproducible, durable, and good electrical per- formance. The production condition of the LIG used for the development of the sensors had an average sheet resistance value of 24.9Ω/ with 1.2 Ω/ of standard deviation. The ther- moresistive sensor developed is characterized by a negative temperature coefficient with a highly linear response, and a sensitivity of 0.71 %℃−1 from 26℃ to 40℃, a suitable interval for its application. The electrochemical cell produced works as a potentiometric pH sensor. Its working electrode (WE) was electropolymerized with polyaniline (PANI) a pH-sensitive bio- compatible electrolyte. The sensor demonstrated a Nernstian behavior with a sensitivity of 53.0 / and 2.3 / of standard deviation on the interval from 2 pH to 9 pH.