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- Development of an immunosensor based on quantum dots with different emissions for the detection of cancer biomarkersPublication . Oliveira, Daniela; Piloto, Ana Margarida L.(Introduction) Cancer is a global health challenge, where early detection is crucial to increasing survival rates [1]. Non-invasive, rapid, and affordable diagnostic methods are urgently needed. Immunosensors emerge as promising alternatives to traditional methods such as ELISA, allowing point-of-care (PoC) analyses [2]. This study introduces a fluorescent probe using cadmium telluride quantum dots (CdTe@MPA QDs) to detect the pancreatic cancer biomarker CA 19-9. With the increasing CA 19-9 concentrations, the fluorescence intensity of green-, orange-, and red-emitting QDs@conjugates was reduced, creating a visible colour gradient under a 365 nm UV lamp. The method, suitable for serum analysis, is highly sensitive and selective, with a detection range of 0.31 to 501.9 U mL-1 and analyzed using ImageJ software. These immunosensors offer significant potential for cancer biomarker detection in clinical diagnostics.
- Molecularly imprinting for ca 15-3 protein detection: a promising biosensor for advanced point-of-care applicationsPublication . Oliveira, Daniela; Barcelay, Yonny Romaguera; Moreira, Felismina(Introduction) Cancer is a public health problem worldwide. Early detection is crucial to improve survival rates [1]. Non-invasive, fast rapid, and low-cost diagnostic methods are urgently needed. Biosensors are a promising alternative to traditional methods such as ELISA, enabling point-ofcare (PoC) analyses. These require biorecognition elements with high selectivity and stability to meet current requirements in PoC diagnostics [2]. This work aims to create an electrochemical biosensor that can detect CA 15-3 with high sensitivity and selectivity. The biosensor consists of molecularly imprinted polymer (MIP) as the biorecognition element, and it is assembled via electrochemical polymerization of a mixture of 3-acrylamidopropyl trimethylammonium chloride (AMPTMA) in the presence of CA 15-3. Electrochemical techniques such as cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) were employed to evaluate the biosensor's electrochemical performance during its optimization and construction. CA 15-3 was successfully detected in a wide concentration range from 0.001 to 100 U mL-1 in just 20 minutes, with an R2 of 0.994. The MIP sensor showed minimal interference with other cancer proteins. This device offers rapid, sensitive, and cost-effective detection of CA 15-3, making it suitable for clinical PoC application.