An antimicrobial peptide can perform differently when the testing medium changes. A classic LL-37 study illustrates this with salt. Reading the organism name and the medium alongside the result is more useful than treating one antibacterial number as a universal property.
What does MIC mean?
MIC is the minimum inhibitory concentration: the lowest concentration that inhibits visible growth under the stated test conditions. It is a laboratory endpoint. It is not a concentration that can be assumed to work in a person, a wound or a cosmetic formulation.
The findings at 100 mM salt
The researchers reported MIC values below 10 micrograms/mL for several organisms even in medium containing 100 mM NaCl. But methicillin-resistant Staphylococcus aureus, Proteus mirabilis and Candida albicans were resistant under those salt conditions and susceptible in low-salt medium. The result was therefore organism- and medium-dependent, rather than uniformly positive.
Why this changes a fair comparison
If one paper uses low-salt medium and another uses a more saline medium, their printed concentrations do not form a clean head-to-head comparison. The strain, growth conditions, assay method and readout also matter. A second LL-37 study reported inhibition of antibacterial and cytotoxic activity in the presence of human serum, reinforcing the importance of the surrounding mixture.
Questions to put beside an antibacterial result
Ask which strain was tested, what the medium contained and whether serum or other proteins were present. Keep bacterial inhibition separate from effects on mammalian cells. When ordering LL-37 for research, specify the sequence and assay purpose so the requested documents address the actual material. Neither a catalogue entry nor a purity percentage establishes the antibacterial performance of a delivered batch.
Related materials and next steps
Explore the NHD catalogue records for LL-37. Confirm the required molecular form, quantity and lot-document availability before relying on a listing for procurement. A catalogue record does not establish equivalence to a published study material.
Send the product or sequence, quantity and document requirements. For more background, browse the analytical methods guides and research glossary.
Sources and reading scope
- LL-37 antimicrobial activities under different salt conditions
- LL-37 conformation and serum-dependent activity
Source links checked 5 October 2026. Research summaries use the accessible original abstract unless a full-text source is explicitly identified. Guidance documents and external supplier explanations are technical references, not NHD batch evidence or a claim of regulatory compliance. Any example introduced as hypothetical or teaching is a calculation, not a measured product result.
NHD catalogue materials are for qualified laboratory research, development and manufacturing enquiries. This article does not provide instructions for human or veterinary use.
Sources & editorial method
AI-assisted writing and source checks; conceptual illustrated cover.
2 linked records are listed in the references below. Read the editorial and AI-assistance policy.
How to interpret this article
Study results and labeled examples are separated. Original-source, arithmetic, readability and internal-link checks; no independent human peer review recorded.
Research-use boundary: Catalog materials discussed on this website are for laboratory research, development and manufacturing use only, not for human or veterinary use. This content is not medical advice and does not provide administration instructions.
Primary records and authoritative sources
- LL-37 antimicrobial activities under different salt conditionsChecked 2026-10-05; source scope is identified in the article.
- LL-37 conformation and serum-dependent activityChecked 2026-10-05; source scope is identified in the article.
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