Related Experiment Video
Updated: May 27, 2026
Evaluation of Antimicrobial Activities of Nanoparticles and Nanostructured Surfaces In Vitro
Published on: April 21, 2023
Antimicrobial acrylic materials with in situ generated silver nanoparticles
James D Oei1, William W Zhao, Lianrui Chu
1Department of Comprehensive Dentistry, Division of Research, University of Texas Health Science Center San Antonio, San Antonio, Texas.
Unlabelled:
Polymethyl methacrylate (PMMA) is widely used to treat traumatic head injuries (cranioplasty) and orthopedic injuries (bone cement), but there is a problem with implant-centered infections. With organisms such as Acinetobacter baumannii and methicillin-resistant staphylococcus aureus developing resistance to antibiotics, there is a need for novel antimicrobial delivery mechanisms without risk of developing resistant organisms.
Objectives:
To develop a novel antimicrobial implant material by generating silver nanoparticles (AgNP) in situ in PMMA.
Results:
All PMMA samples with AgNP's (AgNP-PMMA) released Ag(+) ions in vitro for over 28 days. In vitro antimicrobial assays revealed that these samples (even samples with the slowest release rate) inhibited 99.9% of bacteria against four different strains of bacteria. Long-term antimicrobial assay showed a continued antibacterial effect past 28 days. Some AgNP-loaded PMMA groups had comparable Durometer-D hardness (a measure of degree of cure) and modulus to control PMMA, but all experimental groups had slightly lower ultimate transverse strengths.
Conclusions:
AgNP-PMMA demonstrated a tremendously broad-spectrum and long-intermediate-term antimicrobial effect with comparable mechanical properties to control PMMA. Current efforts are focused on further improving mechanical properties by reducing AgNP loading and assessing fatigue properties.
Insights
This study developed silver nanoparticle-loaded polymethyl methacrylate (AgNP-PMMA) to combat implant infections. AgNP-PMMA demonstrated broad-spectrum antimicrobial activity and sustained silver ion release, offering a promising solution for preventing resistant bacterial infections.
Area of Science:
- Biomaterials Science
- Infectious Disease Research
- Nanotechnology
Background:
- Polymethyl methacrylate (PMMA) is utilized in cranioplasty and orthopedic bone cement but is susceptible to implant-centered infections.
- Increasing antibiotic resistance in bacteria like Acinetobacter baumannii and MRSA necessitates novel antimicrobial strategies.
- There is a critical need for antimicrobial delivery systems that do not promote further resistance.
Purpose of the Study:
- To engineer a novel antimicrobial implant material by synthesizing silver nanoparticles (AgNPs) directly within PMMA.
- To evaluate the antimicrobial efficacy and ion release characteristics of the developed AgNP-PMMA composite.
Main Methods:
- Silver nanoparticles (AgNPs) were generated in situ within PMMA to create AgNP-PMMA composite materials.
- In vitro release of silver ions (Ag+) from AgNP-PMMA samples was monitored over 28 days.
- Antimicrobial assays were performed against four bacterial strains to assess the efficacy of AgNP-PMMA.
- Mechanical properties, including Durometer-D hardness, modulus, and ultimate transverse strength, were evaluated.
Main Results:
- AgNP-PMMA samples exhibited sustained Ag+ ion release in vitro for over 28 days.
- Antimicrobial assays demonstrated that AgNP-PMMA inhibited 99.9% of tested bacteria, including resistant strains.
- A significant, long-term antibacterial effect was observed beyond the 28-day study period.
- While some AgNP-PMMA groups maintained comparable hardness and modulus to control PMMA, ultimate transverse strength was slightly reduced.
Conclusions:
- AgNP-PMMA exhibits broad-spectrum antimicrobial activity with sustained efficacy, addressing the challenge of implant-centered infections.
- The developed material shows promising mechanical properties comparable to conventional PMMA for orthopedic and cranioplasty applications.
- Ongoing research focuses on optimizing mechanical properties by adjusting AgNP loading and evaluating fatigue performance for clinical translation.
