Biology subjects

Albro, M.

Publications and source records attributed to Albro, M..

3 recordsLinked to original sources

bioRxiv2026

Absolute Quantification of Tissue Composition by Raman Spectroscopy

Raman spectroscopy captures the molecular fingerprints of living tissues without labels or tissue destruction. Translating these spectra into absolute measures of tissue biochemical composition remains a challenge owing to tissue-dependent optical properties, variations in sampling volume, and lack of normalization standards requisite for quantitative scaling. Here we introduce a scheme to derive the biochemical constituents of a tissue expressed as a percentage of the tissue wet weight, like biochemical assays, from Raman spectra measured optically. Nonlinear polynomial models of Raman spectra are trained on chemically defined phantoms that mimic the variability of the essential biochemical constituents of a tissue, accommodating spectral overlap and tissue-dependent optical effects. We validated this scheme using cartilage, a tissue fundamental to diarthrodial joint function. Cartilage is comprised of glycosaminoglycans, collagens and water that act synergistically to impart the rheological and tribological material properties essential to tissue function. Using biochemically perturbed live cartilage explants, phantom-calibrated Raman spectroscopy (PC-Raman) resolved constituent-specific changes and achieved quantitative agreement with independent biochemical assays (R-squared = 0.88-0.92; slopes {approx} 1.0; 95% confidence intervals {+/-}2.7-3.2%pt). We demonstrate that PC-Raman is applicable across the hierarchy of tissue interrogation from microscopic imaging of tissue extracellular matrix composition to macroscopic longitudinal monitoring of drug effects in-vitro using live tissue constructs and in-vivo assessments of cartilage regeneration in an equine cartilage repair model. Converting Raman spectra measurements of the essential biochemical constituents of a tissue in absolute terms (tissue wet-weight-%) allows for the non-destructive, longitudinal quantification of tissue composition in disease (tissue degeneration) and in response to treatment (tissue repair).

biochemistry↗

bioRxiv2025

Open Raman Microscopy (ORM): A Modular Hardware and Software Framework for Accessible Raman Imaging

Raman microscopy is a label-free, non-destructive imaging tool for spatially resolved chemical fingerprinting. Its powerful ability to reveal molecular information has driven rapid growth in applications across fields as varied as materials science, environmental analysis, and biomedical research. Despite its versatility, the accessibility of Raman microscopy is limited by expensive commercial setups and the technical barriers faced by researchers attempting to build custom systems. Here, we introduce an Open Raman Microscopy (ORM) framework based on a readily accessible modular microscopy platform. The ORM platform provides configurations for both high-throughput imaging and confocal imaging. We developed a dedicated python-based control and acquisition software, the ORM-Integrated Raman and Imaging Software (ORM-IRIS) designed to accommodate modular integration and control of components, including the laser source, spectrometer, and translational stages. Implemented across three institutions we demonstrate the ORM platform for high-throughput imaging of articular cartilage tissue, confocal three-dimensional imaging of a zebrafish embryo, and imaging of gold colloid decorated surfaces for surface enhanced Raman spectroscopy. Together, this open-source hardware and software framework enhances the accessibility of Raman microscopy across an expanding range of scientific applications.

biophysics↗

bioRxiv2025

A sulfonated cartilage interpenetrating polymer network reinforces and protects the extracellular matrix of degraded cartilage

Cartilage extracellular matrix (ECM) comprises a type-II collagen fibril network that affords structure and tensile strength, complemented by a negatively charged, sulfated glycosaminoglycan (GAG) matrix that retains interstitial water. These components act synergistically, bestowing the rheological and tribological material properties essential to cartilage function. At the onset of osteoarthritis, a disease characterized by cartilage degeneration, GAGs diminish from the ECM reducing interstitial fluid load support (IFLS) and transferring load to the collagen fibril network, which subsequently breaks down, culminating in increased hydraulic permeability, and decreased cartilage stiffness. We restore the material properties of damaged cartilage critical to diarthrodial joint function by forming an interpenetrating polymer network (IPN) with the native collagen using a synthetic, hydrophilic, and biocompatible GAG-mimetic polymer. Upon visible light activation, the monomer, 3-sulfopropylmethacrylate (SPM), and the crosslinker, polyethylene glycol diacrylate (PEGDA), form a sulfonated and anionic IPN that entangles and fills the existing porous degraded collagen matrix. Mechanistically, the highly sulfated, anionic SPM IPN retards water transport, reestablishes collagen fibril network integrity, and restores tissue IFLS, thereby returning the stiffness and viscoelastic properties of degraded cartilage to healthy levels. Additionally, the SPM IPN protects cartilage from further degradation by reducing the infiltration of inflammatory cytokines that upregulate catabolic matrix metalloproteinases and downregulate GAG production. Statement of significanceAmelioration of OA requires a comprehensive approach: neutralize or impede catabolic enzymes that degrade cartilage and reconstitute damaged cartilage by augmenting tissue ECM constituents. Currently, there are no clinical treatments that restore the viscoelastic material properties of hyaline cartilage tissue critical to its mechanical function and impart chondroprotection after OA induction. This work suggests that reconstituting GAG-depleted cartilage using a synthetic sulfonated interpenetrating polymer to reestablish IFLS that can be instilled into the joint and polymerized with white light during conventional arthroscopy represents a novel, minimally invasive, clinical treatment for early OA.

bioengineering↗