Synthesis and Evaluation of Tetramethylguanidinium-Polyethylenimine Polymers as Efficient Gene Delivery Vectors

Abstract

Previously, we demonstrated that 6-(N,N,N′,N′-tetramethylguanidinium chloride)-hexanoyl-polyethylenimine (THP) polymers exhibited significantly enhanced transfection efficiency and cell viability. Here, in the present study, we have synthesized a series of N,N,N′,N′-tetramethylguanidinium-polyethylenimine (TP1-TP5) polymers via a single-step reaction involving peripheral primary amines of bPEI and varying amounts of 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU). These polymers were found to interact efficiently with negatively charged pDNA and formed stable complexes in the size range of ~240–450 nm. Acid-base titration profiles revealed improved buffering capacity of TP polymers as compared to bPEI. Transfection and cytotoxicity assays performed with TP/pDNA complexes on HEK293, CHO, and HeLa cells showed significantly higher transfection efficiency and cell viability with one of the complexes, TP2/pDNA complex, exhibited the highest transfection efficiency (~1.4–2.3-fold) outcompeting native bPEI and the commercially available transfection reagent, Lipofectamine 2000. Compared to previously reported THP polymers, the transfection efficiency of TP/pDNA complexes was found to be lower, as examined by flow cytometry. These results highlight the importance of the hydrophobic C-6 linker in THP polymers in forming compact nanostructures with pDNA, which might lead to efficient uptake and internalization of the complexes; however, the projected TP polymers offer an advantage of their rapid and economical one-step synthesis.

Bifunctionally engineered polyethylenimines as efficient DNA carriers and antibacterials against resistant pathogens

“…To find out the percent cells transfected with the pDNA complexes of HMWP-S, LWMW-S, bPEI and Lipofectamine, flow cytometry was performed. 23 HEK293 cells were seeded at 20,000 cells/well in a 24-well plate and kept it in an incubator overnight. Transfection assay was carried as described above using pDNA complexes of HMWP-S2 (w/w ratios of 5.0, 8.0 and 12.0), LMWP-S3 (w/w ratios of 5.0, 8.0 and 12.0), bPEI (1.8 and 25 kDa, w/w ratios of 1.0, 1.6 and 3.0) and Lipofectamine (according to manufacturer's protocol).…”

“…[20][21][22] However, high cytotoxicity and low hemocompatibility, due to high density of cationic charge, have significantly hampered their clinical efficacy. [23][24][25] In order to enhance transfection efficiency and minimize the toxicity of bPEIs, extensive modifications have been done and reported in the literature. 6,26,27 In an attempt to design multifunctional polymeric systems, we anticipated that the use of streptomycin, 28 a broad spectrum aminoglycoside antibacterial and antimycobacterial, would serve both the purposes, viz.…”

“…20–22 However, high cytotoxicity and low hemocompatibility, due to high density of cationic charge, have significantly hampered their clinical efficacy. 23–25 In order to enhance transfection efficiency and minimize the toxicity of bPEIs, extensive modifications have been done and reported in the literature. 6,26,27…”

Highly water soluble room temperature superionic liquids of APIs

“…Bearing in mind the potential pharmaceutical application of these ionic liquids, we would like to stress that in general protic ILs are usually less toxic than the aprotic ones. [16][17][18][19][20][21] All prepared salts were obtained in high yield (89 to 100%) and purity levels using a sustainable synthetic methodology which guarantees an atom economy process. All novel API ionic liquids or salts were completely characterized by spectroscopic techniques, namely 1 H and 13 C NMR and FTIR, and elemental analysis.…”

Buckyballs conjugated with nucleic acid sequences identifies microorganisms in live cell assays

“…In contrast, Buckyballs have a simpler chemistry for attaching cargo and are non-sticky to the substrate [ 16 ]. Finally, charged polymeric vectors (i) have a much higher molecular weight and of the order of 100 nm [ 21 , 22 ], (ii) lower transfection efficiency of the order 15–50% [ 22 – 24 ], and (iii) can be sticky to the substrate. In contrast, C60 has a lower molecular weight, are of the order of 1 nm, and have higher efficiency as shown later.…”