Further Studies on Cationic Gemini Amphiphiles as Carriers for Gene Delivery─The Effect of Linkers in the Structure and Other Factors Affecting the Transfection Efficacy of These Amphiphiles

Abstract

Gene therapy has the therapeutic potential to address a multitude of health problems, and it also has utility in different domains of science. However, its applications are plagued due to the absence of a suitable, safe, efficient, selective, and universal vector, which could help in delivering the desired nucleic acid cargo to the site of action. Though viral vectors are efficient, they pose various health risks. Different types of synthetic agents have been tried as nucleic acid vectors by researchers but with limited success. Gemini amphiphiles (GAs) are a class of synthetic surfactants having biscationic heads with attached hydrophilic and lipophilic groups. Herein, we synthesized two classes of GAs differing in the chemical nature and length of the linkers, head groups, and lipophilic chains. The resulting compounds were evaluated for their efficiency to transfect A549 and HeLa cell lines with a β-galactosidase reporter plasmid. A 3-oxypentyl linker, a monohydroxyethyl head group, and a tetradecyl moiety as the lipophilic chain offered the best transfection efficiency (compound 10BIII ). Dioleoylphosphatidylethanolamine (DOPE) as the helper lipid improved the transfection efficacy of the GAs in the absence of serum. In the presence of serum, DOPE and cholesterol, as the helper lipids, improved the transfection efficacy of the resulting formulations. The synthesized GAs showed concentration-dependent toxicity in the MTT assay. Biodistribution studies using 99 m Tc-labeled lipoplexes indicated that the lipoplexes got concentrated in some vital organs such as the spleen, liver, and lungs.

Recent Progress in Gene Delivery Systems Based on Gemini‐Surfactant

“…Small-molecule modifications represented an effective strategy to markedly improve the transfection efficiency of GSs. The introduction of small-molecule modifications-such as oligo-oxyethylene spacers [90], carbamate [91], fluorinated groups [92], disulfide ethyl [93] and diethoxy [96] Moreover, cells treated with this optimally formulated lipid complex had better cell viability. This phenomenon was attributed to the two imidazole-cationic headgroups and shortto-moderately-long oligo-oxyethylene spacers, which optimized the interaction with pDNA.…”

“…Small‐molecule modifications represented an effective strategy to markedly improve the transfection efficiency of GSs. The introduction of small‐molecule modifications—such as oligo‐oxyethylene spacers [90], carbamate [91], fluorinated groups [92], disulfide ethyl [93] and diethoxy [96]—into GSs has been shown to effectively enhance transfection efficiency. For example, Kumar et al prepared a series of GSs containing imidazole‐based (Im) head groups and different lengths of oligo‐oxyethylene spacer groups [(C 16 Im) 2 (C 2 O) n ] [90].…”

Recent Progress in Gene Delivery Systems Based on Gemini‐Surfactant

“…Small-molecule modifications represented an effective strategy to markedly improve the transfection efficiency of GSs. The introduction of small-molecule modifications-such as oligo-oxyethylene spacers [90], carbamate [91], fluorinated groups [92], disulfide ethyl [93] and diethoxy [96] Moreover, cells treated with this optimally formulated lipid complex had better cell viability. This phenomenon was attributed to the two imidazole-cationic headgroups and shortto-moderately-long oligo-oxyethylene spacers, which optimized the interaction with pDNA.…”

“…Small‐molecule modifications represented an effective strategy to markedly improve the transfection efficiency of GSs. The introduction of small‐molecule modifications—such as oligo‐oxyethylene spacers [90], carbamate [91], fluorinated groups [92], disulfide ethyl [93] and diethoxy [96]—into GSs has been shown to effectively enhance transfection efficiency. For example, Kumar et al prepared a series of GSs containing imidazole‐based (Im) head groups and different lengths of oligo‐oxyethylene spacer groups [(C 16 Im) 2 (C 2 O) n ] [90].…”

Complexation of Oligo- and Polynucleotides with Methoxyphenyl-Functionalized Imidazolium Surfactants

“…The most traditional non-viral vectors are based on cationic lipids [11][12][13], but there are also reports on the use of cationic surfactants [14,15], peptides [16], ionic liquids [17], polymers [18,19], dendrimers [20], lipid nanoparticles [21], and poly(β-amino esters) [22]. In the last decade, cationic surfactants have been the object of numerous studies as potential gene carriers [23][24][25][26], since they are able to compact DNA molecules into small aggregates and protect them from degradation by nucleases [27]. As a result, they penetrate through cell membranes, releasing the genetic material [20].…”

Recent Progress in Gene Delivery Systems Based on Gemini‐Surfactant

“…Small-molecule modifications represented an effective strategy to markedly improve the transfection efficiency of GSs. The introduction of small-molecule modifications-such as oligo-oxyethylene spacers [90], carbamate [91], fluorinated groups [92], disulfide ethyl [93] and diethoxy [96] Moreover, cells treated with this optimally formulated lipid complex had better cell viability. This phenomenon was attributed to the two imidazole-cationic headgroups and shortto-moderately-long oligo-oxyethylene spacers, which optimized the interaction with pDNA.…”

“…Small‐molecule modifications represented an effective strategy to markedly improve the transfection efficiency of GSs. The introduction of small‐molecule modifications—such as oligo‐oxyethylene spacers [90], carbamate [91], fluorinated groups [92], disulfide ethyl [93] and diethoxy [96]—into GSs has been shown to effectively enhance transfection efficiency. For example, Kumar et al prepared a series of GSs containing imidazole‐based (Im) head groups and different lengths of oligo‐oxyethylene spacer groups [(C 16 Im) 2 (C 2 O) n ] [90].…”

Complexation of Oligo- and Polynucleotides with Methoxyphenyl-Functionalized Imidazolium Surfactants

“…The most traditional non-viral vectors are based on cationic lipids [11][12][13], but there are also reports on the use of cationic surfactants [14,15], peptides [16], ionic liquids [17], polymers [18,19], dendrimers [20], lipid nanoparticles [21], and poly(β-amino esters) [22]. In the last decade, cationic surfactants have been the object of numerous studies as potential gene carriers [23][24][25][26], since they are able to compact DNA molecules into small aggregates and protect them from degradation by nucleases [27]. As a result, they penetrate through cell membranes, releasing the genetic material [20].…”

Recent Progress in Gene Delivery Systems Based on Gemini‐Surfactant

“…Small-molecule modifications represented an effective strategy to markedly improve the transfection efficiency of GSs. The introduction of small-molecule modifications-such as oligo-oxyethylene spacers [90], carbamate [91], fluorinated groups [92], disulfide ethyl [93] and diethoxy [96] Moreover, cells treated with this optimally formulated lipid complex had better cell viability. This phenomenon was attributed to the two imidazole-cationic headgroups and shortto-moderately-long oligo-oxyethylene spacers, which optimized the interaction with pDNA.…”

“…Small‐molecule modifications represented an effective strategy to markedly improve the transfection efficiency of GSs. The introduction of small‐molecule modifications—such as oligo‐oxyethylene spacers [90], carbamate [91], fluorinated groups [92], disulfide ethyl [93] and diethoxy [96]—into GSs has been shown to effectively enhance transfection efficiency. For example, Kumar et al prepared a series of GSs containing imidazole‐based (Im) head groups and different lengths of oligo‐oxyethylene spacer groups [(C 16 Im) 2 (C 2 O) n ] [90].…”

Complexation of Oligo- and Polynucleotides with Methoxyphenyl-Functionalized Imidazolium Surfactants

“…The most traditional non-viral vectors are based on cationic lipids [11][12][13], but there are also reports on the use of cationic surfactants [14,15], peptides [16], ionic liquids [17], polymers [18,19], dendrimers [20], lipid nanoparticles [21], and poly(β-amino esters) [22]. In the last decade, cationic surfactants have been the object of numerous studies as potential gene carriers [23][24][25][26], since they are able to compact DNA molecules into small aggregates and protect them from degradation by nucleases [27]. As a result, they penetrate through cell membranes, releasing the genetic material [20].…”