Biology subjects

Merlo, A.

Publications and source records attributed to Merlo, A..

3 recordsLinked to original sources

bioRxiv2026

Functionalization of Gold Surfaces with Dithiobis(succinimidyl propionate) for Immobilization of Fetuin-A and Assessment of the Attachment and Proliferation of Osteoblast-like Cells

Surface functionalization of biomaterials enables the immobilization of proteins and other molecules and can be utilized to direct the biological response to devices and implants. Fetuin-A is a blood plasma protein involved in numerous physiological processes, including the regulation of mineralization. Notably, many investigations of fetuin-A have explored its cellular interaction when in solution, but limited studies report the role of fetuin-A when used as a surface modifier. The present investigation explores the response elicited by fetuin-A on Saos-2 cells when it is immobilized on a model gold surface through the covalent reaction with dithiobis(succinimdyl propionate) (DSP). Comparative surface characterization using x-ray photoelectron spectroscopy (XPS), atomic force microscopy - infrared spectroscopy (AFM-IR) and surface plasmon resonance (SPR) confirmed the surface modifications but indicate partial inhomogeneity in the functionalizer surface coverage. The interaction of albumin and fetuin-A with the surface was quantified by radiolabeling, quartz crystal microbalance with dissipation (QCM-D) and SPR, demonstrating a higher mass of fetuin-A bound to the surface in comparison to serum albumin. Over 7 days, cells bound to the surfaces with immobilized fetuin-A showed significantly hindered proliferation of osteoblast-like cells compared to the positive control (fibronectin), presumably due to a decrease in cell metabolism. This study provides new insights into the role of fetuin-A in regulating Saos2 cell response and elucidates its potential use in combination with chemical functionalizers for biomedical applications requiring surface modification.

bioengineering↗

bioRxiv2025

The Role of Fetuin-A on the Attachment and Proliferation of Osteoblast-like Cells on Model Gold Surfaces

Fetuin-A is a plasma protein of interest for bone-interfacing applications due to its role in mineralization processes through calcium/phosphate ion-binding capabilities. However, the role of fetuin-A in the initial stages of cellular interaction with biomaterials and the mechanisms involved are not fully clear. This work investigated the response of osteoblast-like Saos-2 cells to model gold substrates presenting pre-adsorbed fetuin-A as a surface modification, to determine the role of the protein in cell attachment and proliferation. Correlative quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance, and radiolabeling confirmed fetuin-A adsorbed on model surfaces in similar quantities compared to serum albumin but formed a less packed layer with increased water entrapment. Surfaces presenting pre-adsorbed fetuin-A enhanced cellular adhesion, similar to fibronectin, but attached cells displayed morphological characteristics more similar to those with pre-adsorbed albumin, with lower average surface area and maximum axis. Over 3 days, fetuin-A exhibited lower cellular proliferation compared to the fibronectin control, likely correlated to the decrease in cellular metabolism observed at the same time-point, and persisted over 7 days. These results provide insight into the role of adsorbed fetuin-A for bone-interfacing implant applications, suggesting the pre-adsorption of the protein alone aids cellular attachment, but is not sufficient to promote early stages of osseointegration.

bioengineering↗

bioRxiv2025

Real-Time Visualization of Calcium Phosphate Formation on Titanium Dioxide Nanoparticles Using Liquid Transmission Electron Microscopy

The integration of titanium dioxide (TiO2) with calcium phosphate (CaP)-based hydroxyapatite (HAP) is a promising strategy for enhancing the bioactivity of bone implants. However, a fundamental understanding of the interfacial reactions governing CaP mineralization on TiO2 remains limited due to lack of characterization techniques with sufficient spatial and temporal resolution in hydrated state. In this study, we combined in situ liquid TEM imaging and correlative ex situ TEM analyses to investigate the nucleation, aggregation, and crystallization of the CaP layer on TiO2 nanoparticle surfaces. Our findings reveal a three-step mineralization process: (1) initial aggregation of TiO2 nanoparticles in solution, (2) formation of an amorphous calcium phosphate-like (ACP-like) layer on the TiO2 surface, leading to an ACP-like coated TiO2 nanoparticle structure, and (3) progressive crystallization of ACP into HAP, forming a HAP-like coated TiO2 nanoparticle structure. Liquid-TEM imaging captured dynamic transformations, including nanoparticle aggregation, structural evolution, and phase transitions, providing unprecedented insights into the physicochemical interactions underlying mineralization. Additionally, we evaluated the effects of electron beam exposure on TiO2 nanoparticles, demonstrating that high electron flux densities can induce morphological instability. This study advances our understanding of CaP-TiO2 interfacial mineralization and offers valuable guidance for optimizing bioactive coatings to improve osseointegration and the long-term stability of bone implants.

bioengineering↗