Toxicity Evaluation of Sulfobetainized Branched Polyethyleneimine via Antibacterial and Biocompatibility Assays

Branched polyethyleneimine (PEI), possessing different types of amines—e.g., primary, secondary, and tertiary—in the polymer chains are well known for their antibacterial properties and DNA condensing ability, affording substantial advantages in many biomedical uses, including gene therapy. However,...

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Main Authors: Mehtap Sahiner, Selin S. Suner, Sahin Demirci, Ramesh S. Ayyala, Nurettin Sahiner
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Toxics
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Online Access:https://www.mdpi.com/2305-6304/13/2/136
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author Mehtap Sahiner
Selin S. Suner
Sahin Demirci
Ramesh S. Ayyala
Nurettin Sahiner
author_facet Mehtap Sahiner
Selin S. Suner
Sahin Demirci
Ramesh S. Ayyala
Nurettin Sahiner
author_sort Mehtap Sahiner
collection DOAJ
description Branched polyethyleneimine (PEI), possessing different types of amines—e.g., primary, secondary, and tertiary—in the polymer chains are well known for their antibacterial properties and DNA condensing ability, affording substantial advantages in many biomedical uses, including gene therapy. However, because of PEI’s toxicity, depending on the molecular weight, its widespread biomedical use is hindered. Therefore, in this study, PEIs with different molecular weights—i.e., 600, 1200, and 1800 g/mol—were modified with 1,3-propane sultone, undergoing a sulfobetainization reaction in a single step to attain a zwitterionic structure: sulfobetainized PEI (b-PEI). The sulfobetainization reaction was carried out twice to increase the zwitterionic repeating unit on PEI chains. The increasing number of SO<sub>3</sub><sup>−</sup> groups on the PEI chains was confirmed by the increased peak intensities around 1160 and 1035 cm<sup>−1</sup> on the FT-IR spectrum, which are assigned to symmetric and asymmetric S=O peaks. The elemental analysis results for first- and second- betainization PEIs, abbreviated as b<sup>1</sup>-PEI and b<sup>2</sup>-PEI, respectively, were revealedthe increased wt% of S confirming the successful multiple-sulfobetainization of the PEI chains. Thermal stability analyses of PEIs and their corresponding multiple-sulfobetainized forms showed that multiple-sulfobetainization reactions increased the thermal stability of bare PEI chains. PEIs with lower molecular weights exhibited more antimicrobial properties. As PEI is sulfobetainated, its antimicrobial properties can be further adjusted via sulfobetainization (once or twice), or by adjusting the corresponding solution pH, or by protonating them with different acids with different counter anions. The cell toxicity of PEI on L929 fibroblast cells was slightly increased by increasing the molecular weight of the PEI, but all forms of sulfobetainized PEIs were found to be safe (no toxicity), even at 1000 µg/mL concentrations.
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spelling doaj-art-7511df64e6824b4a8b5dc5b0d5f964aa2025-08-20T02:45:38ZengMDPI AGToxics2305-63042025-02-0113213610.3390/toxics13020136Toxicity Evaluation of Sulfobetainized Branched Polyethyleneimine via Antibacterial and Biocompatibility AssaysMehtap Sahiner0Selin S. Suner1Sahin Demirci2Ramesh S. Ayyala3Nurettin Sahiner4Department of Bioengineering, Faculty of Engineering, Canakkale Onsekiz Mart University, Terzioglu Campus, 17100 Canakkale, TurkeyDepartment of Chemistry, Faculty of Sciences, Canakkale Onsekiz Mart University, Terzioglu Campus, 17100 Canakkale, TurkeyDepartment of Food Engineering, Faculty of Engineering, Istanbul Aydin University, Florya Halit Aydin Campus, 34153 Istanbul, TurkeyDepartment of Ophthalmology, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd, MDC21, Tampa, FL 33612, USADepartment of Chemistry, Faculty of Sciences, Canakkale Onsekiz Mart University, Terzioglu Campus, 17100 Canakkale, TurkeyBranched polyethyleneimine (PEI), possessing different types of amines—e.g., primary, secondary, and tertiary—in the polymer chains are well known for their antibacterial properties and DNA condensing ability, affording substantial advantages in many biomedical uses, including gene therapy. However, because of PEI’s toxicity, depending on the molecular weight, its widespread biomedical use is hindered. Therefore, in this study, PEIs with different molecular weights—i.e., 600, 1200, and 1800 g/mol—were modified with 1,3-propane sultone, undergoing a sulfobetainization reaction in a single step to attain a zwitterionic structure: sulfobetainized PEI (b-PEI). The sulfobetainization reaction was carried out twice to increase the zwitterionic repeating unit on PEI chains. The increasing number of SO<sub>3</sub><sup>−</sup> groups on the PEI chains was confirmed by the increased peak intensities around 1160 and 1035 cm<sup>−1</sup> on the FT-IR spectrum, which are assigned to symmetric and asymmetric S=O peaks. The elemental analysis results for first- and second- betainization PEIs, abbreviated as b<sup>1</sup>-PEI and b<sup>2</sup>-PEI, respectively, were revealedthe increased wt% of S confirming the successful multiple-sulfobetainization of the PEI chains. Thermal stability analyses of PEIs and their corresponding multiple-sulfobetainized forms showed that multiple-sulfobetainization reactions increased the thermal stability of bare PEI chains. PEIs with lower molecular weights exhibited more antimicrobial properties. As PEI is sulfobetainated, its antimicrobial properties can be further adjusted via sulfobetainization (once or twice), or by adjusting the corresponding solution pH, or by protonating them with different acids with different counter anions. The cell toxicity of PEI on L929 fibroblast cells was slightly increased by increasing the molecular weight of the PEI, but all forms of sulfobetainized PEIs were found to be safe (no toxicity), even at 1000 µg/mL concentrations.https://www.mdpi.com/2305-6304/13/2/136biocompatible polyethyleneiminebetainized PEIzwitter ionic PEIsulfobetainizationmultiple betainization
spellingShingle Mehtap Sahiner
Selin S. Suner
Sahin Demirci
Ramesh S. Ayyala
Nurettin Sahiner
Toxicity Evaluation of Sulfobetainized Branched Polyethyleneimine via Antibacterial and Biocompatibility Assays
Toxics
biocompatible polyethyleneimine
betainized PEI
zwitter ionic PEI
sulfobetainization
multiple betainization
title Toxicity Evaluation of Sulfobetainized Branched Polyethyleneimine via Antibacterial and Biocompatibility Assays
title_full Toxicity Evaluation of Sulfobetainized Branched Polyethyleneimine via Antibacterial and Biocompatibility Assays
title_fullStr Toxicity Evaluation of Sulfobetainized Branched Polyethyleneimine via Antibacterial and Biocompatibility Assays
title_full_unstemmed Toxicity Evaluation of Sulfobetainized Branched Polyethyleneimine via Antibacterial and Biocompatibility Assays
title_short Toxicity Evaluation of Sulfobetainized Branched Polyethyleneimine via Antibacterial and Biocompatibility Assays
title_sort toxicity evaluation of sulfobetainized branched polyethyleneimine via antibacterial and biocompatibility assays
topic biocompatible polyethyleneimine
betainized PEI
zwitter ionic PEI
sulfobetainization
multiple betainization
url https://www.mdpi.com/2305-6304/13/2/136
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AT sahindemirci toxicityevaluationofsulfobetainizedbranchedpolyethyleneimineviaantibacterialandbiocompatibilityassays
AT rameshsayyala toxicityevaluationofsulfobetainizedbranchedpolyethyleneimineviaantibacterialandbiocompatibilityassays
AT nurettinsahiner toxicityevaluationofsulfobetainizedbranchedpolyethyleneimineviaantibacterialandbiocompatibilityassays