Doctoral themes 2023

Optical Detection of RNA Biomarkers by Plasmon-Enhanced Single Molecule Emission

Supervisors

Pedro Paulo, pedro.m.paulo@tecnico.ulisboa.pt

João Tomé, jtome@tecnico.ulisboa.pt

Registration Institution

Instituto Superior Técnico

Project description

Design, preparation, and study of porphyrin-oligoDNAs, luminescent labels to be incorporated onto a gold nanosensor to detect RNA biomarkers with single-molecule sensitivity. Porphyrin-oligoDNAs have been used in many applications, including as staples on origami DNA nanotechnology.₁ This powerful approach for bottom-up/self-assembly nanofabrication allows the immobilization of photoactive molecules with nanoscale precision, which is required for advanced optical and photonic applications. The project aims at the development of highly sensitive optical biosensors based on porphyrin label reporters and gold nanorod antennas for signal amplification. It will start from the porphyrin synthesis to be used as the core platform for different biomoieties, such as carbohydrates. Later, the porphyrin dyes will be conjugated onto custom-synthesized DNA oligonucleotides to produce the dye reporter sequence. The combination of a porphyrin dye label emitting in the near infrared with a gold nanodimer antenna is sought here to achieve detection sensitivities down to single-molecule level,₂ which can provide for digital sensor readouts. The proof-of-concept will be performed with RNA sequences proposed as cell free nucleic acid biomarkers. The project will be developed under the supervision of Dr. Pedro Paulo and Prof. João Tomé, with the collaboration of Prof. Miguel Prazeres (DBE/IST). It is also planned a 3–6-month research mobility to Photochemistry & Photobiology group at University of Granada (Spain).

References: 1) J. Nanobiotechnol, 2022, 20, 257; 2) J. Phys. Chem. Lett. 2019, 10, 1542

Keywords

Porphyrins

DNA nanotechnology

Nanoplasmonic antennas

Biomarkers

Clinical diagnostic