Role of Gemini Surfactants with Variable Spacers and SiO

Area of Science:

• Supramolecular Chemistry
• Nanotechnology
• Biomaterials Science

Background:

• Cationic gemini surfactants are explored for their ability to interact with and compact nucleic acids.
• Silica nanoparticles (SiO2 NPs) can potentially enhance the efficacy of drug delivery systems.
• Calf thymus DNA (ct-DNA) serves as a model for studying DNA compaction and delivery.

Purpose of the Study:

• To investigate the compaction of ct-DNA by two cationic gemini surfactants (12-4-12 and 12-8-12) with and without SiO2 NPs.
• To evaluate the cytotoxicity and cellular uptake of these surfactant-NP complexes.
• To assess the in vivo tumor accumulation and therapeutic potential of the optimized system.

Main Methods:

• Spectroscopic techniques (fluorescence anisotropy, lifetime) and ethidium bromide exclusion assays were used to study DNA-surfactant interactions.
• Cell viability assays (MTT) were performed on HEK 293 and 4T1 cell lines.
• In vitro cellular uptake studies using fluorescence microscopy and flow cytometry, and in vivo tumor imaging in mice.

Main Results:

• The gemini surfactant 12-8-12, with its longer hydrophobic spacer, showed more efficient ct-DNA compaction than 12-4-12, especially with SiO2 NPs.
• The 12-8-12/SiO2 NP complex exhibited significantly lower cytotoxicity in HEK 293 cells and higher dose-dependent cytotoxicity in 4T1 cancer cells compared to DTAB.
• In vivo studies demonstrated that 12-8-12/SiO2 NPs delivered the highest amount of ct-DNA into tumors in a time-dependent manner.

Conclusions:

• Gemini surfactants, particularly 12-8-12, in combination with SiO2 NPs, are effective in compacting ct-DNA.
• The 12-8-12/SiO2 NP system shows promising potential for targeted nucleic acid delivery in cancer therapy due to enhanced tumor accumulation.
• This study warrants further investigation into gemini surfactant-SiO2 NP complexes for advanced nucleic acid-based cancer treatments.