Arianna Toppi

PhD project by Arianna Toppi

Name: Arianna Toppi
Project Title: Multiplex digital analysis of serum samples for Alzheimer’s disease diagnostics
Group: Fluidic Array Systems and Technology
Supervisor: Martin Dufva

Project Description:
This PhD project is part of the BBDiag, an Innovative Training Networks funded under the EU H2020 Marie Skłodowska-Curie Actions to train thirteen Early Stage Researchers (ESRs) in the field of blood biomarker-based diagnostics for early-stage Alzheimer’s disease (AD), and it aims at developing a novel and highly sensitive analysis based on multiplexed droplet arrays for the simultaneous detection of several biomarkers. Multiplexing is essential as the use of several biomarkers simultaneously often increases the selectivity and sensitivity of the test.

The research project is based on the use of a hydrophilic-in-hydrophobic spot array, which have been developed previously in this research group. This is a powerful way to create millions of fL sized aqueous droplets on a surface in seconds, with a water/air interface. This kind of platform, embedded in a chip-based flowsystem, can be modified for multiplexed detection of single molecules in Alzheimer’s disease patients’ serum, allowing us to perform a highly sensitive digital analysis without the use of off-chip pre-analytical steps.

Currently, there is a lack of methods with a high sensitivity and specificity, able to quantitatively detect low abundance AD biomarkers (i.e. proteins or oligonucleotides) in biofluids, like cerebral spinal fluid and serum that leads to a late diagnosis and hence to poor patient prognosis. Therefore, the development of such a detection system that enables an early diagnosis of the disease is important in order to find suitable medical treatments that may improve the life-quality of patients. 

Illustration Figure 1. Work flow of DA for a sandwich immunoassay. 1) Sample incubation with a Droplet Array substrate where antibodies are immobilised on hydrophilic spots surrounded by a hydrophobic background (dark grey). During that incubation, target (green) is immobilised and the assay is tuned so that one target molecule statistically binds to a spot. 2) Washing. 3) Incubations with secondary antibodies (yellow) conjugated with HPR or b-galactosidase enzymes (blue). 4) Washing. 5) Production of droplets with the fluorescent enzyme substrate.  



Martin Dufva
Gruppeleder, Lektor
DTU Sundhedsteknologi
51 33 37 53