Spirulina platensis sustainable lipid extracts in alginate-based nanocarriers: An algal approach against biofilms

International audienceCyanobacteria and especially Spirulina platensis are recognized as abundant resources of lipids and polyunsaturated fatty acids (PUFA). The main valorization of these lipids has been the biofuel production but another approach was developed here: the investigation of S. platensis fatty acids as anti-biofilm agent for skin diseases. In fact, chronic wounds represent an important burden for occidental health care systems, and are usually related to the presence of a biofilm, especially of Candida species.In order to develop a biomimetic approach against Candida biofilm formation, free fatty acids (FFA) isolated from microalgae S. platensis were explored. Four solvents, including three bio-sourced ones, and three extraction conditions were screened. Lipid and pigment amounts, combined with FFA profiles were analyzed to select the optimal conditions: 30 min of ultrasonic extraction using dimethylcarbonate or ethylacetate as extraction solvent. A vectorization using a macroalgal-alginate nanocarrier was successfully performed. Vectorized extracts were safe towards keratinocytes and thus compatible with a topical use. Spirulina lipid-enriched extracts showed a high anti-biofilm growth activity at low concentrations (about 80% inhibition after 24 h at 0.2 mg/mL). The combination of extracts in copper-alginate nanocarriers potentiated the anti-biofilm growth activity and exhibited a good anti-biofilm activity (about 50% inhibition after 24 h at 0.1 mg/mL). The combined approach of encapsulated Spirulina lipid extracts represented thus a relevant concept to develop all in one anti-biofilm weapons against Candida and represent a new perspective for algae biomass valorization