Biology subjects

DiCecco, L.-A.

Publications and source records attributed to DiCecco, L.-A..

3 recordsLinked to original sources

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↗

bioRxiv2023

Liquid Transmission Electron Microscopy for Probing Collagen Biomineralization

Collagen biomineralization is foundational to hard tissue assembly. While studied extensively, collagen mineralization processes are not fully understood as the majority of theories are derived from electron microscopy (EM) in static, dehydrated, or frozen conditions, unlike the liquid phase environment where mineralization occurs dynamically. Herein, novel liquid transmission EM (TEM) strategies are presented, where collagen mineralization was explored in liquid conditions for the first time. Custom thin-film enclosures were employed to visualize the mineralization of reconstituted collagen fibrils in a calcium-phosphate and polyaspartic acid solution to promote intrafibrillar mineralization. TEM highlighted that at early time points, precursor mineral particles attached to collagen and progressed to crystalline mineral platelets aligned with fibrils at later time points. This aligns with observations from other techniques and validates this liquid TEM approach. This work provides a new liquid imaging approach for exploring collagen biomineralization, advancing toward understanding disease pathogenesis and remineralization strategies for hard tissues.

bioengineering↗

bioRxiv2020

A Facile Method for Simultaneous Visualization of Wet Cells and Nanostructured Biomaterials in SEM using Ionic Liquids

This work presents a successful methodology to image mammalian cells adhered to nanostructured biomaterials using scanning electron microscopy (SEM) operating in low-vacuum mode following ionic liquid treatment. Human osteoblast-like Saos-2 cells were treated with a room-temperature ionic liquid, 1-Ethyl-3-methylimidazolium tetrafluoroborate, and subsequently imaged on titanium utilizing SEM. Titanium substrates were modified to create laser-induced periodic surface structures (LIPSS) for visualizing at the sub-micron scale. Using a combination of fluorescence-based cell metabolism along with light microscopy and SEM image analysis, the shape and location of irradiated cells were confirmed to be unchanged after multiple irradiation sessions while the viability of minimally irradiated cells was unaltered. The wet imaging conditions combined with a rapid facile protocol using ionic liquid allows this technique to fulfill a niche in examining cellular behavior on biomaterials with sub-micron surface features. The demonstrated method to track observed cell adhesion to sub-micron surface features with SEM has great implications for the understanding of cell migration on nanostructured surfaces as well as on the exploration of simpler SEM preparation methods for cellular imaging.

cell biology↗