Development of a low-cost, non-enzymatic glucose sensor based on copper nanoparticles and laser-induced graphene towards wearable sensing

• Autor(a) principal: Caetano, Joana Cunha
• 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/10362/147767
• topic: Glucose; paper biosensor; laser-induced graphene; copper nanoparticles; onestep synthesis; non-enzymatic; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

According to the International Diabetes Federation (IDF), in 2021 approximately 537 million adults (20 to 79 years) suffered from diabetes, which corresponds to a total of 10.5 % of the world’s adult population, and its prevalence is predicted to rise dramatically in the following years. Since glucose sensors constitute an effective approach for diabetes management, by providing precise information about glucose levels, the glucose sensor market has experienced enormous growth in the last few years. However, due to the high cost of the commercially available glucose detection solutions and since the rise in the number of diabetic patients has been more pronounced in low and middle-income countries, there is a high demand for low-cost glucose monitoring systems. In order to address the lack of inexpensive glucose sensors issue, this thesis aims to meet the presented necessity in three strands: the development of a glucose sensor based on copper nanoparticles (CuNPs) and Laser-Induced Graphene (LIG), fabricated on paper substrate. Firstly, the LIG technique offers a rapid and simple method for the production of graphitized material, which is an extremely conductive composite and valuable for the sensing field, without the need for expensive and complex fabrication techniques. Moreover, it allows the LIG production on paper, which is a more sustainable, flexible, economic and easily accessible alternative than other commonly used substrates. For the non-enzymatic glucose detection, a cheap copper precursor was selected for the laser-induced CuNPs formation, presenting highly catalytic activity towards the glucose oxidation. Thus, CuNPs and LIG composites were simultaneously synthesized in one fabrication step, allowing for a large-scale sensor production. LIG was fabricated with a sheet resistance value as low as 14.8 Ω sq−1. The sensor showed good glucose sensing performance (267 μA mM−1 cm−2 sensitivity, 11 μM detection limit, and high selectivity and reproducibility) with a linear range within the glucose concentration range detected in sweat (20 μM - 1.79 mM), opening the possibility of integrating this method into a wearable and non-invasive glucose monitoring system.