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Updated: Feb 28, 2026
High Throughput, Real-time, Dual-readout Testing of Intracellular Antimicrobial Activity and Eukaryotic Cell Cytotoxicity
Published on: November 16, 2016
In vitro cytotoxicity of antimicrobial conjugated electrolytes: interactions with mammalian cells
Kristin N Wilde1, David G Whitten, Heather E Canavan
1Center for Biomedical Engineering, Department of Chemical and Nuclear Engineering, MSC01-1141, University of New Mexico , Albuquerque, New Mexico 87131, United States.
Abstract:
An estimated 19 000 deaths and $3-4 billion in health care costs per year in the United States are attributed to methicillin-resistant Staphlococcus aureus (MRSA) infections. Certain conjugated phenylene ethynylene (CPE)-based polymers (PPE) and oligomers (OPE) have been demonstrated to exhibit dark and light-activated antimicrobial activity. Until recently, the relative cytotoxicity of these PPEs and OPEs toward mammalian cells haas been unknown, limiting the applications for which they may be used (e.g., reducing and/or preventing the spread of untreatable bacterial strains). In this work, we examine the toxicity of CPEs to mammalian cells using cytotoxicity assays of cellular monolayers. Eight CPEs, two PPEs and six OPEs, were selected for these studies based on their biocidal activity, and diversity of repeat unit number and functional groups. Briefly, two cell types were exposed to CPEs at concentrations ranging from 1-100 ug/mL for 24 h. We find that concentration largely determines the resulting viability of cells, although at intermediate concentrations (5-10 ug/mL), the effect of light on light-activated compounds is very important. Furthermore, we find that the longer-chained compounds are cytotoxic at much higher concentrations, and therefore have the widest range of concentrations available for potential applications.
Insights
Conjugated phenylene ethynylene (CPE) compounds show antimicrobial properties. Longer-chained CPEs are less toxic to mammalian cells, widening their potential applications against infections like MRSA.
Area of Science:
- Polymer Chemistry
- Materials Science
- Toxicology
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) causes significant mortality and healthcare costs.
- Conjugated phenylene ethynylene (CPE)-based polymers and oligomers show antimicrobial activity.
- Mammalian cell cytotoxicity of CPEs was previously unknown, limiting their therapeutic applications.
Purpose of the Study:
- To evaluate the cytotoxicity of various CPEs against mammalian cells.
- To determine how factors like compound structure and light exposure affect CPE toxicity.
- To identify CPEs with a favorable toxicity profile for potential antimicrobial applications.
Main Methods:
- Cytotoxicity assays were performed on two mammalian cell types.
- Eight CPEs (two polymers, six oligomers) were tested at concentrations from 1-100 ug/mL for 24 hours.
- Cellular viability was assessed to determine toxicity levels.
Main Results:
- Cellular viability was primarily dependent on CPE concentration.
- Light exposure significantly impacted the toxicity of light-activated CPEs at intermediate concentrations (5-10 ug/mL).
- Longer-chained CPEs exhibited lower cytotoxicity, allowing for a broader range of effective concentrations.
Conclusions:
- CPE concentration is a key factor in determining mammalian cell toxicity.
- Light-activated CPEs require careful concentration management, especially at intermediate levels.
- Longer-chained CPEs present a promising therapeutic window for developing novel antimicrobial agents against MRSA and other resistant bacteria.
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