Guanidinium containing Poly(methacrylamide)s for non-viral gene delivery

Guanidinium nach der bahnbrechenden Entdeckung seiner Funktion bei der Zellpenetration des Tat-Proteins von HIV-1 zunehmend anerkannt, was einen neuen Weg für die Entwicklung von Guanidinium-reichen Transportern eröffnete. Abgesehen von der Fähigkeit zur Zellpenetration wurde festgestellt, dass Guanidinium spezielle Wechselwirkungen mit Nukleinsäuren hervorrufen kann. Daher wurden Guanidinium-reiche Transporter für die nicht-virale Genübertragung verwendet. Aufgrund der strukturellen und funktionellen Freiheit polymerer Vektoren wurden Guanidiniumgruppen auch in Polymerketten eingebaut und in verschiedenen Studien auf nicht-viralen Gentransport untersucht. Das Potenzial von GCPs für die nicht-virale Genübertragung wurde jedoch noch nicht vollständig aufgeklärt. Bisher umfassten die meisten Entwürfe für polymere Vektoren primäre, sekundäre und tertiäre Amingruppen als Quelle der kationischen Ladung. Auf der anderen Seite gibt es für GCPs noch viel mehr zu entdecken. Daher zeigt die vorgestellte Arbeit prominente Studien zu GCPs für den nicht-viralen Gentransfer. Jedes Kapitel illustrierte unterschiedliche Polymerdesigns, indem es die Vielseitigkeit der RAFT-Polymerisation betonte. Die Polymerdesigns wurden unter Verwendung von Methacrylamid-Monomeren mit bioinspirierten Seitengruppen erstellt, um die Polymervektoren mit maximaler Leistung zu erhalten

Incorporation of indole significantly improves the transfection efficiency of guanidinium‐containing poly(methacrylamide)s

Abstract A highly efficient transfection agent is reported that is based on terpolymer consisting of N ‐(2‐hydroxypropyl)methacrylamide (HPMA), N ‐(3‐guanidinopropyl) methacrylamide (GPMA), and N ‐(2‐indolethyl)methacrylamide monomers (IEMA) by analogy to the amphipathic cell‐penetrating peptides containing tryptophan and arginine residues. The incorporation of the indole‐bearing monomer leads to successful plasmid DNA condensation even at a nitrogen‐to‐phosphate (N/P) ratio of 1. The hydrodynamic diameter of polyplexes is determined to be below 200 nm for all N/P ratios. The transfection studies demonstrate a 200‐fold increase of the transgene expression in comparison to P(HPMA‐co‐GPMA) with the same guanidinium content. This study reveals the strong potential of the indole group as a side‐chain pendant group that can increase the cellular uptake of polymers and the transfection efficiency of the respective polyplexes

Indole, phenyl, and phenol Groups: The role of the comonomer on gene delivery in guanidinium containing methacrylamide terpolymers

Abstract This report highlights the importance of hydrophobic groups mimicking the side chains of aromatic amino acids, which are tryptophan, phenylalanine, and tyrosine, in guanidinium bearing poly(methacrylamide)s for the design of non‐viral gene delivery agents. Guanidinium containing methacrylamide terpolymers are prepared by aqueous reversible addition–fragmentation chain transfer ( a RAFT) polymerization with different hydrophobic monomers, N ‐(2‐indolethyl)methacrylamide (IEMA), N ‐phenethylmethacrylamide (PhEMA), or N ‐(4‐hydroxyphenethyl)methacrylamide (PhOHEMA) by aiming similar contents. The well‐defined polymers are obtained with a molar mass of ≈15 000 g mol −1 and ≈1.1 dispersity. All terpolymers demonstrate almost comparable in vitro cell viability and hemocompatibility profiles independent of the type of side chain. Although they all form positively charged, enzymatically stable polyplexes with plasmid DNA smaller than 200 nm, the incorporation of the IEMA monomer improve these parameters by demonstrating a higher DNA binding affinity and forming nanoassemblies of about 100 nm. These physicochemical characteristics are correlated with increased transfection rates in CHO‐K1 cells dependent on the type of the monomer and the nitrogen to phosphate (N/P) ratio of the polyplexes, as determined by luciferase reporter gene assays

PEGylation of Guanidinium and Indole Bearing Poly(methacrylamide)s – Biocompatible Terpolymers for pDNA Delivery

This study describes the first example for shielding of a high performing terpolymer that consists of N ‐(2‐hydroxypropyl)methacrylamide (HPMA), N ‐(3‐guanidinopropyl)methacrylamide (GPMA), and N ‐(2‐indolethyl)methacrylamide monomers (IEMA) by block copolymerization of a polyethylene glycol derivative – poly(nona(ethylene glycol)methyl ether methacrylate) (P(MEO 9 MA)) via reversible addition–fragmentation chain transfer (RAFT) polymerization. The molecular weight of P(MEO 9 MA) is varied from 3 to 40 kg mol –1 while the comonomer content of HPMA, GPMA, and IEMA is kept comparable. The influence of P(MEO 9 MA) block with various molecular weights is investigated over cytotoxicity, plasmid DNA (pDNA) binding, and transfection efficiency of the resulting polyplexes. Overall, the increase in molecular weight of P(MEO 9 MA) block demonstrates excellent biocompatibility with higher cell viability in L‐929 cells and an efficient binding to pDNA at N/P ratio of 2. The significant transfection efficiency in CHO‐K1 cells at N/P ratio 20 is obtained for block copolymers with molecular weight of P(MEO 9 MA) up to 10 kg mol –1 . Moreover, a fluorescently labeled analogue of P(MEO 9 MA), bearing perylene monoimide methacrylamide (PMIM), is introduced as a comonomer in RAFT polymerization. Polyplexes consisting of labeled block copolymer with 20 kg mol –1 of P(MEO 9 MA) and pDNA are incubated in Hela cells and investigated through structured illumination microscopy (SIM)

Comparison of suction and oedometer methods for the measurement of swell pressure

In this paper, a thermocouple psychrometric technique is used to measure soil suction and assess the reliability of a swell pressure prediction method. Kaolinite-bentonite clay mixtures were prepared to obtain expansive soils with a wide range of plasticities. Suction measurements using thermocouple psychrometers and constant volume swell tests in oedometers were made on statically compacted :specimens. Soil suction-water content relationships were evaluated. The results indicate a linear relationship between the logarithm of initial soil suction and swell pressure measured in the oedometer. it has been shown that the method proposed by Johnson & Snethen for the prediction of swell pressure using suction measurements overestimates the ultimate swell pressure

Comparison of suction and oedometer methods for the measurement of swell pressure

In this paper, a thermocouple psychrometric technique is used to measure soil suction and assess the reliability of a swell pressure prediction method. Kaolinite-bentonite clay mixtures were prepared to obtain expansive soils with a wide range of plasticities. Suction measurements using thermocouple psychrometers and constant volume swell tests in oedometers were made on statically compacted :specimens. Soil suction-water content relationships were evaluated. The results indicate a linear relationship between the logarithm of initial soil suction and swell pressure measured in the oedometer. it has been shown that the method proposed by Johnson & Snethen for the prediction of swell pressure using suction measurements overestimates the ultimate swell pressure