Related Experiment Video
Updated: May 18, 2026
Quantifying the Effects of Antimicrobials on In vitro Biofilm Architecture using COMSTAT Software
Published on: December 14, 2020
Quantification of antibiotic in biofilm-inhibiting multilayers by 7.87 eV laser desorption postionization MS imaging
Melvin Blaze M T1, Artem Akhmetov, Berdan Aydin
1Department of Chemistry, MC 111, University of Illinois at Chicago, Chicago, Illinois 60607, United States.
Abstract:
The potential of laser desorption postionization mass spectrometry (LDPI-MS) imaging for small molecule quantification is demonstrated here. The N-methylpiperazine acetamide (MPA) of ampicillin was adsorbed into polyelectrolyte multilayer surface coatings composed of chitosan and alginate, both high molecular weight biopolymers. These MPA-ampicillin spiked multilayers were then shown to inhibit the growth of Enterococcus faecalis biofilms that play a role in early stage infection of implanted medical devices. Finally, LDPI-MS imaging using 7.87 eV single-photon ionization was found to detect MPA-ampicillin within the multilayers before and after biofilm growth with limits of quantification and detection of 0.6 and 0.3 nmol, respectively. The capabilities of LDPI-MS imaging for small molecule quantification are compared to those of MALDI-MS. Furthermore, these results indicate that 7.87 eV LDPI-MS imaging should be applicable to quantification of a range of small molecular species on a variety of complex organic and biological surfaces. Finally, while MS imaging for quantification was demonstrated here using LDPI, it is a generally useful strategy that can be applied to other methods.
Insights
Laser desorption postionization mass spectrometry (LDPI-MS) imaging effectively quantifies small molecules like N-methylpiperazine acetamide (MPA)-ampicillin in biopolymer coatings. This technique shows promise for analyzing complex biological surfaces and medical device infections.
Area of Science:
- Analytical Chemistry
- Biomaterials Science
- Microbiology
Background:
- Polyelectrolyte multilayers (PEMs) are used in medical devices.
- Enterococcus faecalis biofilms contribute to device-related infections.
- Accurate quantification of small molecules in biological systems is challenging.
Purpose of the Study:
- To demonstrate the potential of laser desorption postionization mass spectrometry (LDPI-MS) imaging for small molecule quantification.
- To investigate the use of MPA-ampicillin in chitosan-alginate multilayers for inhibiting E. faecalis biofilm growth.
- To compare LDPI-MS imaging with MALDI-MS for small molecule quantification.
Main Methods:
- Fabrication of chitosan-alginate polyelectrolyte multilayer surface coatings.
- Spiking multilayers with N-methylpiperazine acetamide (MPA)-ampicillin.
- Inoculation of multilayers with Enterococcus faecalis to promote biofilm formation.
- Analysis using 7.87 eV single-photon ionization LDPI-MS imaging.
- Comparison with MALDI-MS.
Main Results:
- LDPI-MS imaging successfully detected MPA-ampicillin in multilayers before and after biofilm growth.
- Limits of quantification and detection for MPA-ampicillin were determined to be 0.6 nmol and 0.3 nmol, respectively.
- The MPA-ampicillin spiked multilayers demonstrated inhibition of E. faecalis biofilm growth.
Conclusions:
- 7.87 eV LDPI-MS imaging is a viable method for small molecule quantification on complex surfaces.
- LDPI-MS imaging offers advantages for analyzing small molecules in biological and organic samples.
- MS imaging, particularly LDPI, presents a generally useful strategy for quantification in various applications.
