This work describes the quick and simple fabrication of toner-based 96-microzone plates by a direct-printing technology. The printer deposits a toner layer (ca. 5 μm thick) on the polyester surface which acts as a hydrophobic barrier to confine small volumes of sample on test zones (wells). A 96-microzone toner plate was explored to demonstrate its capability of performing enzyme-linked immunosorbent assay (ELISA). The detection of anti-immunoglobulin G (anti-IgG) and immunoglobulin M (IgM) antibodies has been successfully achieved in cell culture and serum samples, respectively. The use of a conventional microplate reader has allowed obtaining a limit of detection of 13 fmol of mouse IgG per zone on printed microplates. The IgM antibody has been detected in a serum sample collected from a patient infected with dengue virus. The detection of a primary infection has been provided by a microplate reader and also by a cell phone camera. Besides the bioanalytical feasibility, toner-based zones have shown good repeatability for inter-zone and intra-plate comparisons. The relative standard deviation (RSD) values for inter-zone (n = 12) and intra-plate (n = 3) comparisons were lower than 6% and 11%, respectively. Furthermore, it was found that the lifetime of each printed microplate depends on the storage temperature. The shelf life for devices stored at 10 °C has been estimated to be ca. four weeks.

Dengue diagnosis was performed on printed microzones based on colorimetric detection of IgG and IgM biomarkers in serum samples through enzyme-linked-immunosorbent assay experiments.

This chapter describes the development of microfluidic toner-based analytical devices (μTADs) to perform clinical diagnostics using a scanner or cell-phone camera. μTADs have been produced in a platform composed of polyester and toner by the direct-printing technology (DPT) in a matter of minutes. This technology offers simplicity and versatility, and it does not require any sophisticated instrumentation. Toner-based devices integrate the current generation of disposable analytical devices along paper-based chips. The cost of one μTAD has been estimated to be lower than $0.10. In addition, these platforms are lightweight and portable thus enabling their use for point-of-care applications. In the last 5 years, great efforts have been dedicated to spread out the use of μTADs in bioassays. The current chapter reports the fabrication of printed microplates and integrated microfluidic toner-based devices for dengue diagnostics and rapid colorimetric assays with clinically relevant analytes including cholesterol, triglycerides, total proteins, and glucose. The use of μTADs associated with cell-phone camera may contribute to the health care, in special, to people housed in developing regions or with limited access to clinics and hospitals.

Adjuvantes são substâncias associadas aos antígenos que aumentam ou modificam a resposta imune. Este trabalho constitui uma comparação do perfil de anticorpos em grupos de murinos imunizados com IgG humana associada ou não a adjuvantes, através da técnica de Enzyme Linked Immunosorbent Assay (ELISA) no 28 o e 40º dia após esquema de imunização previamente delineado. Os adjuvantes avaliados nesse estudo foram o hidróxido de alumínio e o adjuvante de Freund. Os resultados demonstraram que no 28º dia os animais imunizados com adjuvantes exibiram valores de absorbância mais altos em comparação com animais imunizados sem adjuvantes e os murinos imunizados com hidróxido de alumínio e adjuvante de Freund apresentaram valores de densidade ótica semelhantes. Em contradição, no 40º dia nos três grupos de camundongos estudados, o perfil de anticorpos anti -Ig G humana foram análogos.