Biology subjects

Riera Brillas, R.

Publications and source records attributed to Riera Brillas, R..

3 recordsLinked to original sources

bioRxiv2026

Single-molecule imaging and tracking on clinical liquid biopsies reveals cancer biomarkers nanoscale organization and heterogeneity

Single-molecule imaging and tracking have revealed fundamental biological mechanisms at the molecular scale, yet their application to clinical research remains limited by technical complexity and sample preparation incompatible with patient-derived specimens. As a result, we lack information with molecular-scale resolution of clinically relevant biomarkers. Here, we develop a workflow enabling Points Accumulation in Nanoscale Topography (PAINT) combined with single-particle tracking (SPT) on clinical liquid biopsies, allowing analysis of biomarker nanoscale organization at the single-molecule level in cancer patients. Our approach features a sample preparation tailored to liquid biopsies and requires no fixation, covalent labelling, or genetic modification, making single-molecule imaging compatible with hospital clinical workflows. We demonstrate the methods diversity by imaging liquid biopsies from blood, bone marrow aspirates, and pleural effusions across different cancer types. PAINT-SPT captures both the expression and mobility of clinically relevant membrane receptor biomarkers, revealing pronounced inter- and intra-patient heterogeneity at the molecular and cellular levels. We discover that individual patients exhibit distinct molecular mobility fingerprints that reflect biomarker interaction states and correlate with clinical diagnostic readouts. Furthermore, these fingerprints distinguish healthy from cancer cells, enabling the development of a classifier that accurately identifies cancer cells based on their single-molecule behaviour. Together, our results establish a route to investigate patient-derived clinical samples at the single-molecule level and open new opportunities to understand cancer biology and biomarker function beyond ensemble-averaged measurements.

biophysics↗

bioRxiv2024

Unveiling DNA Origami Interaction Dynamics on Living Cell Surfaces by Single Particle Tracking

Due to the unique spatial addressability of DNA origami, targeting ligands (e.g. aptamers or antibodies) can be specifically positioned onto the surface of the nanostructure, constituting an essential tool for studying ligand-receptor interactions at the cell surface. While the design and ligand incorporation into DNA origami nanostructures are well-established, the study of cell surface interaction dynamics is still in the explorative phase, where in depth fundamental understanding on the molecular interactions remains underexplored. This study uniquely captures real-time encounters between DNA origami and cells in-situ using single particle tracking (SPT). Here, we functionalized DNA nanorods (NRs) with antibodies or aptamers specific to the epidermal growth factor receptor (EGFR) and used them to target EGFR-overexpressing cancer cells. SPT data revealed that ligand coated NRs selectively bound to the receptors expressed in target cancer cells, while non-functionalized NRs only display negligible cell interactions. Furthermore, we explored the effect of ligand density on the DNA origami, which revealed that aptamer-decorated NRs exhibit non-linear binding characteristics, whereas this effect in antibody-decorated NRs was less pronounced. This study provides new mechanistic insights into the fundamental understanding of DNA origami behaviour at the cell interface, with unprecedented spatiotemporal resolution, aiding the rational design of ligand-targeted DNA origami for biomedical applications.

bioengineering↗

bioRxiv2019

Efficient small-scale conjugation of DNA to primary antibodies for multiplexed cellular targeting

The combination of the specificity of antibodies and the programmability of DNA nanotechnology has provided the scientific community with a powerful tool to label and unambiguously distinguish a large number of subcellular targets using fluorescence-based read-out methods. While primary antibodies are commercially available for a large class of targets, a general stoichiometric site-specific DNA labeling strategy for this affinity reagent is lacking. Here, we present a universal, site-selective, conjugation method using a small photocrosslinkable protein G adaptor that allows labeling of antibodies of different host species with a controlled number of short oligonucleotides (ODNs). Importantly, we illustrate that this conjugation method can be directly performed on commercially-available primary antibodies, on a small scale and without cross-reactivity towards other proteins, such as bovine serum albumin. In addition, we present a general, benchtop-compatible strategy to purify DNA-labeled antibodies without loss of function. The application of protein G-ODN labeled primary antibodies is demonstrated by employing three well-known methods for detecting subcellular targets using fluorescent read-out, including flow cytometry, DNA-PAINT, and dSTORM. This work thus establishes a general and efficient platform for the synthesis of a library of unique ODN-antibody conjugates, facilitating the broader use of DNA-based programmable tags for multiplexed labeling to identify subcellular features with nanometer-precision, improving our understanding of cellular structure and function.

biochemistry↗