Multi-Parameter Analysis of Photosynthetic and Molecular Responses in Chlorella vulgaris Exposed to Silver Nanoparticles and Ions

Komazec, Bruno; Vitko, Sandra; Balen, Biljana; Cindrić, Mario; Biba, Renata; Peharec Štefanić, Petra (2025) Multi-Parameter Analysis of Photosynthetic and Molecular Responses in Chlorella vulgaris Exposed to Silver Nanoparticles and Ions. Toxics, 13 (8). ISSN 2305-6304

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Abstract

Due to widespread use of silver nanoparticles (AgNPs), the assessment of their potential harm to microalgal photosynthesis is crucial, as microalgae, together with cyanobacteria, contribute to approximately 50% of global oxygen production. This study investigated photosynthetic pigments, photosynthetic rate, chlorophyll a fluorescence, and the expression of photosynthesis-related genes and proteins in green alga Chlorella vulgaris after 72 h exposure to citrate- and cetyltrimethylammonium bromide (CTAB)-stabilized AgNPs, as well as silver ions (AgNO3), at concentrations allowing 75% cell survival (EC25). All treatments impaired photosynthetic performance. The most pronounced decreases in chlorophyll fluorescence parameters and photosynthetic rate, alongside elevated energy dissipation, were observed after exposure to AgNP-CTAB and AgNO3. AgNP-citrate had milder effects and induced compensatory responses, reflected in an increased performance index and upregulation of photosynthesis-related proteins. AgNP-CTAB induced the strongest downregulation of gene and protein expression, likely due to its higher EC25 concentration and cationic surface promoting interaction with photosynthetic structures. Although AgNO3 caused fewer molecular changes, it significantly disrupted photosynthetic function, suggesting a direct effect of Ag+ ions on photosynthesis-related proteins. Overall, the results highlight the role of AgNPs’ surface coatings and dosage in determining their phytotoxicity, with photosystem disruption and oxidative stress emerging as key mechanisms of action.

Item Type:	Article
Uncontrolled Keywords:	silver nanoparticle coating; chlorophyll fluorescence; proteomics; 2-D electrophoresis; mass spectrometry; gene expression; qPCR
Subjects:	NATURAL SCIENCES > Biology > Biochemistry and Molecular Biology
Divisions:	Division of Molecular Medicine
Projects:	Project title Project leader Project code Project type Interaktivni učinci mikroplastike i nanosrebra na kopnene i vodene biljke i alge Biljana Balen IP-2022-10-3824 HrZZ Metaproteomika patvorenih namirnica Mario Cindrić NPOO.C3.2.R3-I1.04.0122 Eu
Depositing User:	Lorena Palameta
Date Deposited:	02 Sep 2025 08:59
URI:	http://fulir.irb.hr/id/eprint/9950
DOI:	10.3390/toxics13080627

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