Odd–Even Effect of Repeating Aminoethylene Units in the Side Chain of N-Substituted Polyaspartamides on Gene Transfection Profiles

Uchida, Hirokuni; Miyata, Kanjiro; Oba, Makoto; Ishii, Takehiko; Suma, Tomoya; Itaka, Keiji; Nishiyama, Nobuhiro; Kataoka, Kazunori

doi:10.1021/ja204466y

Cited by 200 publications

(223 citation statements)

References 34 publications

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“…Synthesis of 2-((tert-butoxycarbonyl)(2-((tert-butoxycarbonyl)amino)ethyl)amino)ethyl methacrylate (BocAEAEMA) (2). The amine containing monomer was synthesized according to the procedure shown in Scheme 1.…”

Section: Synthetic Methodsmentioning

confidence: 99%

A new proton sponge polymer synthesized by RAFT polymerization for intracellular delivery of biotherapeutics

et al. 2014

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A spermine-like polymer was synthesized via reversible addition-fragmentation chain transfer polymerization as a potential endosomal escaping agent. A new methacrylate monomer, 2-((tertbutoxycarbonyl)(2-((tert-butoxycarbonyl)amino)ethyl)amino)ethylmethacrylate (BocAEAEMA), was prepared and then polymerized via RAFT polymerization at constant monomer or initiator concentration increase in M n with monomer conversion was also observed. P(BocAEAEMA)s with controlled molecular weights and narrow molecular weight distributions were obtained. The in vitro cytotoxicity and proton sponge capacity of deprotected polymers P(AEAEMA) were investigated in comparison with a widely used endosomal-disruptive polymer, PEI. P(AEAEMA)s were found to possess proton sponge capacity comparable with PEI. More importantly, P(AEAEMA)s were not toxic on NIH 3T3 cells at concentrations where PEI (25 kDa) was highly toxic (0.4 mM and above). P(AEAEMA) was able to fully condense a DNA fragment at nitrogen/phosphate (N/P) ratios of 10 and above, as evidenced by gel electrophoresis. P(BocAEAEMA) was then chain-extended with a model sugar monomer, mannose-acrylate (ManAc), to yield P(AEAEMA)-b-P(ManAc) block copolymers, to potentially provide cell-recognition ability to the polyplex particles. Although the presence of the P(ManAc) block partially inhibited the interaction of P(AEAEMA) with DNA, P(AEAEMA) 13 -b-P(ManAc) 7 was able to form polyplexes with DNA at N/P ratios ranging between 20/1 and 2/1. Dynamic light scattering measurements showed that while P(AEAEMA) (M n ¼ 5.5 kDa) and DNA formed polyplex particles having a hydrodynamic diameter (D h ) of 125 AE 51 nm, P(AEAEMA) 13 -b-P(ManAc) 7 and DNA formed particles with a smaller D h of 38 AE 10 nm.

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Section: Synthetic Methodsmentioning

confidence: 99%

A new proton sponge polymer synthesized by RAFT polymerization for intracellular delivery of biotherapeutics

et al. 2014

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“…4). 31,32) Interestingly, PAsp(dET) revealed minimal membrane destabilization at physiological pH (pH ca. 7), although there was a significant enhancement in membrane destabilization at acidic pHs mimicking the late endosomal compartment (pH ca.…”

Section: Intracellular Trafficking Controlla-ble Polyplex Micellesmentioning

confidence: 99%

Study on Development of Polymeric Micellar Gene Carrier and Evaluation of Its Functionality

Oba

2013

Biological & Pharmaceutical Bulletin

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Polymeric micelles, which are formed by the self-assembly of block copolymers, can load various substances and have received attention as drug carriers. Negatively charged nucleic acids such as DNA or RNA are some of the drugs delivered by polyion complex-based polymeric micelles (polyplex micelles). Polyplex micelles are expected to be nonviral gene carriers instead of viral vectors, which have several problems including safety, the limited size of the loading gene, and productivity. In this review, recent studies by our group on smart polyplex micelles delivering genes will be introduced.

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“…According to the scattered light intensity of the polymer solutions, polymers were soluble (at 5 mg mL À1 ) in HEPES buffered solution (HBS, pH 7.3) up to 55 % FPBA modification, that is (PEG-b-P(Lys/FPBA 23 ) 42 , however, those with 66 % (that is (PEG-b-P(Lys/FPBA 28 ) 42 ) or higher degrees of FPBA modification were partially insoluble because of the strong hydrophobicity of FPBA (data not shown). The HBS-soluble series of polymers, that is PEG-b-P(Lys/FPBA 0,10,19,23 ) 42 , were allowed to complex with siRNA at various N/P ratios, which is defined as the molar …”

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confidence: 99%

A Phenylboronate‐Functionalized Polyion Complex Micelle for ATP‐Triggered Release of siRNA

et al. 2012

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Therapeutics based on small interfering RNA (siRNA) offer an attractive clinical option because of its ability to silence genes in a highly sequence-specific manner.[1] A key challenge lies in developing a delivery system that helps protect the siRNAs from endogenous RNase degradation while allowing for controlled pharmacokinetics. One promising approach is a formulation of polyion complex (PIC) micelles that spontaneously form in an aqueous environment simply through electrostatic interactions between the anionic siRNA and cationic polymers.[2] With versatile designs of the counterpart cationic polymers, representative poly(ethylene glycol) based block co-polymers, many creative PIC-based strategies have emerged, some of which have shown encouraging in vitro gene silencing abilities. [3][4][5] However, in general, these PIC-based carriers suffer from instability under physiological conditions, primarily because of the relatively short chain length of the siRNA, that is 20-25 nucleotides, which results in poor thermodynamic stability. Therefore, stabilization of the PIC-based carriers so that programmed destabilization upon arrival at the site of intracellular targets (to release siRNA) has been of interest. Current efforts have focused on either one or combinations of the following three representative approaches: covalent conjugation of siRNAs to a homing polymer, [3,[6][7][8] introduction of hydrophobic moieties to reinforce the core-aggregation, [9][10][11] and crosslinking the core aggregate by disulfide bridging. [5,12] As such, the combination of these approaches often results in a highly complex structure and method of preparation.Herein, we describe a sophisticated solution that can remarkably simplify the synthesis of PICs. It uses a phenylboronate functionality, which incorporates all of the aforementioned methods of stabilization (Scheme 1) while maintaining a wide window of control for environmental sensitivity. Phenylboronic acid (PBA) is a synthetic molecule capable of forming reversible covalent esters with 1,2-or 1,3-cis-diols including on a ribose ring, [13][14][15] a structure which is present at the 3' end of RNAs and several kinds of ribonucleotides. Because of this property, PBA has historically been used as a ligand for RNA in affinity chromatography.[16] Therefore, this binding property offers a facile route for chemical conjugation of siRNAs to the pendant PBA groups. Once electrostatically condensed into the PIC, the chances of equilibrium binding are increased, in which intermolecular cross-links could also form because of the bis-bidentate ribose arrangement at the 3' end of the double-stranded siRNA, thereby further stabilizing the complex. Furthermore, PBA is unique in that it undergoes a dramatic inversion in its level of hydrophobicity depending on the degree of acid disassociation; [17] it is strongly hydrophobic when uncharged but it becomes hydrophilic when negatively charged at pH values above its pK a . As shown in Figure 1, the binding between PBA and siRNAs is essentially a ...

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Odd–Even Effect of Repeating Aminoethylene Units in the Side Chain of N-Substituted Polyaspartamides on Gene Transfection Profiles

Cited by 200 publications

References 34 publications

A new proton sponge polymer synthesized by RAFT polymerization for intracellular delivery of biotherapeutics

A new proton sponge polymer synthesized by RAFT polymerization for intracellular delivery of biotherapeutics

Study on Development of Polymeric Micellar Gene Carrier and Evaluation of Its Functionality

A Phenylboronate‐Functionalized Polyion Complex Micelle for ATP‐Triggered Release of siRNA

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