Photoluminescent Scaffolds Based on Natural and Synthetic Biodegradable Polymers for Bioimaging and Tissue...

Area of Science:

• Biomaterials Science
• Nanotechnology
• Tissue Engineering

Background:

• Non-invasive monitoring of tissue-engineered constructs in vivo is crucial but challenging.
• Upconversion nanoparticles (UCNPs) offer potential as photoluminescent nanomarkers for tracking biological processes.

Purpose of the Study:

• To synthesize and evaluate polymer scaffolds loaded with UCNPs for non-invasive visualization and monitoring of tissue regeneration.
• To assess the biocompatibility and biodegradation of UCNP-loaded scaffolds in a living organism.

Main Methods:

• Synthesis of β-NaYF₄:Yb³⁺, Er³⁺ UCNPs and their incorporation into collagen (COL), hyaluronic acid (HA), and polylactic-co-glycolic acid (PLGA) scaffolds.
• Subcutaneous implantation of scaffolds in BALB/c mice followed by histomorphological analysis to assess tissue response.
• In vivo visualization and photoluminescent analysis of implanted scaffolds using an epi-luminescent imaging system with 975 nm laser excitation.

Main Results:

• Histomorphological analysis revealed weak inflammatory responses for HA and PLGA scaffolds, and moderate for COL scaffolds.
• In vivo photoluminescent imaging demonstrated a gradual decrease in the UCNP signal, indicating scaffold biodegradation and nanoparticle release.
• Photoluminescent data showed satisfactory correlation with histomorphological findings.

Conclusions:

• UCNP-loaded polymer scaffolds are suitable for non-invasive monitoring of tissue-engineered constructs in vivo.
• The UCNP signal decrease provides a reliable indicator of scaffold biodegradation and nanoparticle release.
• The study validates the combined use of UCNPs and polymer scaffolds for advanced tissue engineering applications.