Biology subjects

Perego, L.

Publications and source records attributed to Perego, L..

6 recordsLinked to original sources

bioRxiv2026

Extracellular Matrix Stiffness Controls Actin Cytoskeletal Tension

Mechanical properties of the extracellular matrix (ECM) regulate cell behavior and strongly impact the cytoskeleton, yet direct measurements of actin tension across different ECM stiffnesses are lacking. Using a genetically encoded FRET-based actin tension sensor, we show that cells cultured on stiffer substrates exhibit increased spreading, reduced multicellular aggregation, and higher molecular tension within filamentous actin. Complementary measurements using an -actinin tension sensor support increased cytoskeletal mechanical loading. These results provide direct evidence that ECM stiffness modulates intracellular actin tension during mechanotransduction.

biophysics↗

bioRxiv2025

Ultrasensitive saliva-based detection of early Alzheimer's disease biomarkers via nanoparticle-enhanced evanescent scattering microscopy

Alzheimers disease (AD) is the most common neurodegenerative disease, yet early diagnosis remains a major challenge. Current cerebrospinal fluid (CSF) assays are invasive and unsuitable for large-scale or repeated screening. Blood-based biomarkers have achieved sensitivities above 90%, but still face challenges of standardization, cost, technical complexity, and the need for sophisticated instrumentation. Saliva offers an attractive, non-invasive solution; however, the low concentrations of AD biomarkers have thus far hindered its clinical applicability. Here, we introduce a saliva-based diagnostic platform that combines Total Internal Reflection Scattering (TIRS) microscopy with antibody-functionalized metallic nanoparticles (NPs), for ultrasensitive, real-time quantification of salivary amyloid-{beta} (A{beta}) proteins. Using two established AD mouse models (APPsl and 5xFAD), we found that salivary A{beta}2 levels robustly distinguish transgenic from wild-type animals and correlate with brain amyloid deposition. Pooled and stratified analyses suggest these associations are primarily driven by the transgenic-wild-type contrast rather than linear changes within groups. Predictive modeling further confirmed diagnostic utility: in APPsl, Logistic Regression and Support Vector Machine (SVM) classifiers both achieved 92% accuracy with balanced sensitivity and specificity, while in 5xFAD, SVM reached 88% accuracy with perfect specificity. These results establish the NPs-enhanced TIRS sensor as a rapid, accurate and non-invasive tool for AD detection via saliva. By addressing a critical unmet need in neurodegenerative disease screening, this platform has strong potential to transform early diagnosis, enable timely interventions, and support biomarker-guided clinical trials. Its simplicity, speed, and scalability, make it well-suited for point-of-care diagnostics and large-scale screening initiatives. One Sentence SummaryUltrasensitive saliva test detects early Alzheimers biomarkers using nanoparticle-enhanced scattering microscopy

biochemistry↗

bioRxiv2025

Myelinated fiber labeling and orientation mapping of the human brain with light-sheet fluorescence microscopy

The convoluted network of myelinated fibers that supports behavior, cognition, and sensory processing in the human brain is the source of its extraordinary complexity. Advancements in tissue optical clearing, 3D fluorescence microscopy, and automated image analysis have enabled unprecedented insights into the architecture of these networks. Here, we investigate the multiscale organization of myelinated fibers in human brain tissue from the brainstem, Brocas area, hippocampus, and primary visual cortex by exploiting a specific fiber staining method, light-sheet fluorescence microscopy (LSFM), and an advanced spatial orientation analysis tool. Using an optimized protocol that integrates tissue clearing with the lipophilic DiD probe to achieve uniform and deep myelinated fiber labeling, we generate micrometerresolution volumetric reconstructions of multiple brain regions through an inverted LSFM. Automated image processing, employing unsupervised 3D multiscale Frangi filters, provides orientation distribution functions and local orientation dispersion maps. This enables precise characterization of the directionality of white matter bundles, linking mesoscopic structural properties to orientation details computed at the native micrometric resolution of the LSFM apparatus. The presented workflow illustrates a robust platform for large-scale, high-resolution brain mapping, which may facilitate the investigation of pathological alterations with unparalleled spatial resolution and, furthermore, the validation of other neuroimaging modalities.

neuroscience↗

bioRxiv2024

Quantitative cytoarchitectural phenotyping of deparaffinized human brain tissues

Advanced 3D imaging techniques and image segmentation and classification methods can profoundly transform biomedical research by offering deep insights into the cytoarchitecture of the human brain in relation to pathological conditions. Here, we propose a comprehensive pipeline for performing 3D imaging and automated quantitative cellular phenotyping on Formalin-Fixed Paraffin-Embedded (FFPE) human brain specimens, a valuable yet underutilized resource. We exploited the versatility of our method by applying it to different human specimens from both adult and pediatric, normal and abnormal brain regions. Quantitative data on neuronal volume, ellipticity, local density, and spatial clustering level were obtained from a machine learning-based analysis of the 3D cytoarchitectural organization of cells identified by different molecular markers in two subjects with malformations of cortical development (MCD). This approach will grant access to a wide range of physiological and pathological paraffin-embedded clinical specimens, allowing for volumetric imaging and quantitative analysis of human brain samples at cellular resolution. Possible genotype-phenotype correlations can be unveiled, providing new insights into the pathogenesis of various brain diseases and enlarging treatment opportunities.

neuroscience↗

bioRxiv2024

A compact prism-based microscope for high sensitive measurements in fluid biopsy

The increasing demand for sensitive, portable, and cost-effective disease detection methods has raised significant interest in the development of biosensors for rapid and early-stage diagnosis, population mass-screening, and bedside monitoring. Although a certain number of sensing devices with high sensitivity has experienced considerable progress, their practical application has been hindered by challenges in replicating instrumental systems, obtaining rapid and multiplexed signals, and the high cost of manufacturing. In response, we present a streamlined prism-based Total Internal Reflection system which, in combination with surface functionalization techniques on gold nanoparticles, is capable of facilitating Evanescent Wave scattering for the highly sensitive and rapid detection of specific analytes in synthetic liquids and real human samples. The system achieves a remarkable limit of detection of 1 fg/mL concentration for the targeted pathological biomarker. Our innovative design addresses the limitations of existing technologies by reducing costs, minimising overall size, and ensuring swift biofluid analysis with remarkable sensitivity. To validate its efficacy, we conducted scattering experiments in synthetic and human serum samples, exploiting functionalized AuNPs to recognize bacterial lipopolysaccharides as biomarkers for sepsis disease. The cohesive integration of these techniques hopefully makes this biosensing setup a promising candidate for potential clinical deployment, meeting the pressing requirements for rapid personalised diagnosis, large-scale population screening and bed-monitoring.

biophysics↗

bioRxiv2021

Probing mechanotransduction in living cells by optical tweezers and FRET-based molecular force microscopy

Cells sense mechanical signals and forces to probe the external environment and adapt to tissue morphogenesis, external mechanical stresses, and a wide range of diverse mechanical cues. Here, we propose a combination of optical tools to manipulate single cells and measure the propagation of mechanical and biochemical signals inside them. Optical tweezers are used to trap microbeads that are used as handles to manipulate the cell plasma membrane; genetically encoded FRET-based force sensors inserted in F-actin and alpha-actinin are used to measure the propagation of mechanical signals to the cell cytoskeleton; while fluorescence microscopy with single molecule sensitivity can be used with a huge array of biochemical and genetic sensors. We describe the details of the setup implementation, the calibration of the basic components and preliminary characterization of actin and alpha-actinin FRET-based force sensors.

biophysics↗