DNA aptamer-based sandwich microfluidic assays for dual quantification and multi-glycan profiling of cancer biomarkers

• Published in: Biosensors & bioelectronics 2016-05, Vol.79, p.313-319
• Main Authors: Jolly, Pawan, Damborsky, Pavel, Madaboosi, Narayanan, Soares, Ruben R.G., Chu, Virginia, Conde, João P., Katrlik, Jaroslav, Estrela, Pedro
• Format: Article
• Language: English
• Subjects: Antibodies; Aptamers, Nucleotide - chemistry; Assaying; Biomarkers, Tumor - isolation & purification; Biosensing Techniques - methods; Cancer; Diagnosis; DNA aptamer; ELISA; Enzyme-Linked Immunosorbent Assay; Glycoprofiling; Humans; Lectins; Male; Microfluidics; Microfluidics - methods; Polysaccharides - isolation & purification; Prognosis; Prostate; Prostate cancer; Prostate-Specific Antigen - isolation & purification; Prostatic Neoplasms - diagnosis; Prostatic Neoplasms - pathology; Sambucus nigra; Sandwich assay
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2015.12.058

Two novel sandwich-based immunoassays for prostate cancer (PCa) diagnosis are reported, in which the primary antibody for capture is replaced by a DNA aptamer. The assays, which can be performed in parallel, were developed in a microfluidic device and tested for the detection of free Prostate Specific Antigen (fPSA). A secondary antibody (Aptamer–Antibody Assay) or a lectin (Aptamer–Lectin Assay) is used to quantify, by chemiluminescence, both the amount of fPSA and its glycosylation levels. The use of aptamers enables a more reliable, selective and controlled sensing of the analyte. The dual approach provides sensitive detection of fPSA along with selective fPSA glycoprofiling, which is of significant importance in the diagnosis and prognosis of PCa, as tumor progression is associated with changes in fPSA glycosylation. With these approaches, we can potentially detect 0.5ng/mL of fPSA and 3ng/mL of glycosylated fPSA using Sambucus nigra (SNA) lectin, both within the relevant clinical range. The approach can be applied to a wide range of biomarkers, thus providing a good alternative to standard antibody-based immunoassays with significant impact in medical diagnosis and prognosis. •Two novel sandwich-based immunoassays for prostate cancer diagnosis are reported, in which the primary antibody for capture is replaced by a DNA aptamer.•The two assays allow the simultaneous detection of protein cancer biomarkers and their glycosylation levels, allowing improved diagnosis of the disease.•The aptamer-based ELISA-type chemiluminescence assay was performed in a microfluidic device.•Free Prostate Specific Antigen and its glycosylation were detected within the clinical range as a test case study.