Size-Dependent Bioactivity of Silver Nanoparticles and Calcium Hydroxide Mixtures Against hDPSCs: An In Vitro Study

Area of Science:

• Biomaterials Science
• Stem Cell Biology
• Nanotechnology

Background:

• Dental pulp stem cells (hDPSCs) are crucial for pulp regeneration.
• Calcium hydroxide [Ca(OH)2] is a standard root canal filling material.
• Silver nanoparticles (AgNPs) offer antimicrobial properties but their biocompatibility with stem cells needs evaluation.

Purpose of the Study:

• To assess the biocompatibility and bioactivity of AgNP-Ca(OH)2 mixtures with hDPSCs.
• To compare the effects of different AgNP sizes (2 nm, 5 nm, 10 nm) combined with Ca(OH)2.
• To evaluate cell viability, proliferation, differentiation, and inflammatory responses.

Main Methods:

• hDPSCs were treated with Ca(OH)2 alone, AgNP-Ca(OH)2 mixtures, or triple antibiotic paste (TAP).
• Cell viability assessed via Cell Counting Kit-8 and LIVE/DEAD assay.
• Reactive oxygen species (ROS), cytokine profiles (TGF-β1, IL-1β, TNF-α), and alkaline phosphatase (ALP) measured using ELISA.
• Mineralization evaluated using Alizarin Red S staining.

Main Results:

• Ca(OH)2 alone and the 10 nm AgNP mixture showed highest cell viability and lowest ROS.
• 2 nm and 5 nm AgNP mixtures decreased viability and caused cell distortion.
• Both Ca(OH)2 alone and 10 nm mixture promoted TGF-β1, suppressed IL-1β and TNF-α, and increased ALP and mineralization.
• Significant differences observed between groups (Kruskal-Wallis test, p < 0.05).

Conclusions:

• Ca(OH)2 alone and the 10 nm AgNP mixture are biocompatible with hDPSCs.
• These agents enhance hDPSC viability, proliferation, differentiation, and mineralization.
• A favorable anti-inflammatory response was observed with Ca(OH)2 and 10 nm AgNP mixture.