Dual pH-sensitive and UCST-type thermosensitive dendrimers: phenylalanine-modified polyamidoamine dendrimers with carboxyl termini

Tamaki, Mamiko; Fukushima, Daichi; Kojima, Chie

doi:10.1039/c8ra05381b

Cited by 18 publications

(32 citation statements)

References 24 publications

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“…PAMAM-Suc-Phe was synthesized by reacting the amino-terminal PAMAM dendrimer of G4 with succinic anhydride and the subsequent phenylalanine benzyl ester (Phe-OBzl) prior to the deprotection of the OBzl group, in accordance with our previous report. 27 In contrast, PAMAM-Phe-Suc was synthesized by reacting the amino-terminal PAMAM dendrimer with N-(tert-butoxycarbonyl)phenylalanine (Boc-Phe) and subsequent succinic anhydride aer the deprotection of the Boc group. The bound numbers of succinic anhydride and Phe residues to the dendrimer were estimated from the proton nuclear magnetic resonance ( 1 H NMR) spectra (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Because deprotonated terminal carboxylate anion and inner tertiary ammonium cation are zwitterionic at pH 5, PAMAM-Suc-Phe exhibited UCST-type thermosensitivity at pH 5. 27 When almost all terminal carboxylic acid was protonated at pH 3, PAMAM-Suc-Phe became soluble at room temperature due to the positive surface charge. Although the protonated tertiary amines were located at the branched point of the dendrimer, the positive charge might have been exposed at the surface by the conformation change.…”

Section: Ph-and Thermo-sensitive Behaviors Of Two Carboxy-terminal Phmentioning

confidence: 99%

“…This suggests that coacervation (liquid-liquid phase separation) occurred during the phase transition, similar to UCST-type phase transition of PAMAM-Suc-Phe. 27…”

Section: Coacervationmentioning

confidence: 99%

“…26 Conversely, the carboxyterminal Phe-modied dendrimers showed UCST-type thermosensitivity at acidic pH. 27 Carboxy-terminal Phe-modied PAMAM dendrimers are zwitterionic; they have anionic carboxy groups at the termini and tertiary amino groups in the dendrimer. It is most likely that the zwitterionic structure induces the UCST-type thermosensitive behaviors of the carboxy-terminal Phe-modied dendrimers.…”

Section: Introductionmentioning

confidence: 99%

“…It is most likely that the zwitterionic structure induces the UCST-type thermosensitive behaviors of the carboxy-terminal Phe-modied dendrimers. 27 In this study, various zwitterionic Phe-modied dendrimers were designed and synthesized. First, two carboxy-terminal PAMAM dendrimers (PAMAM-Phe-Suc and PAMAM-Suc-Phe) were produced by changing the reaction order of acid anhydride and Phe.…”

Section: Introductionmentioning

confidence: 99%

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pH-Switchable LCST/UCST-type thermosensitive behaviors of phenylalanine-modified zwitterionic dendrimers

Tamaki

Kojima

2020

RSC Adv.

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Thermosensitive polymers are useful as intelligent materials. Dendrimers have well-defined structures, which can work as multifunctional polymers. In this study, we designed and synthesized various phenylalanine (Phe)-modified zwitterionic dendrimers as pH-and thermo-sensitive polymers. First, polyamidoamine (PAMAM) dendrimers were modified with Phe and succinic anhydride (Suc) to prepare carboxy-terminal Phe-modified dendrimers (PAMAM-Suc-Phe and PAMAM-Phe-Suc). Both these dendrimers showed upper critical solution temperature (UCST)-type thermosensitivity. Interestingly, PAMAM-Phe-Suc demonstrated lower critical solution temperature (LCST)-type thermosensitivity at lower pH, but PAMAM-Suc-Phe did not. This indicates that PAMAM-Phe-Suc can switch LCST/UCSTtype thermosensitivity according to the solution's pH. PAMAM-Phe-SO 3 Na with sulfonic acid termini also demonstrated LCST/UCST-type thermosensitivity switched by pH, with a higher sensitivity than PAMAM-Phe-Suc. Coacervation occurred during the phase separation. The quaternized dendrimers (QPAMAM-Phe-Suc and QPAMAM-Phe-SO 3 Na) and dendrimers conjugating isoleucine or 4-(amino methyl)benzoic acid did not show the unique thermosensitive properties, indicating that the tertiary amines in the dendrimer core and the Phe residues at the termini are indispensable. PAMAM-Phe-SO 3 Na could separate a model compound (rose bengal) from an aqueous solution because of its encapsulation ability. This is the first report of pH-switchable LCST/UCST-type thermosensitive dendrimers. 72 254 8190; Tel: +81 72 254 8190 † Electronic supplementary information (ESI) available: Experimental section; summary of synthesized dendrimers with different generations; NMR and FT-IR spectra of synthesized dendrimers; the pH titration proles; and temperature-dependent transmittance curves of obtained dendrimers under various conditions. See

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Section: Resultsmentioning

confidence: 99%

Section: Ph-and Thermo-sensitive Behaviors Of Two Carboxy-terminal Phmentioning

confidence: 99%

“…This suggests that coacervation (liquid-liquid phase separation) occurred during the phase transition, similar to UCST-type phase transition of PAMAM-Suc-Phe. 27…”

Section: Coacervationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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pH-Switchable LCST/UCST-type thermosensitive behaviors of phenylalanine-modified zwitterionic dendrimers

Tamaki

Kojima

2020

RSC Adv.

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A Naked‐eye Colorimetric pH and Temperature Sensor Based on Gold Nanoparticle‐Loaded Stimuli‐Sensitive Dendrimers

et al. 2022

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Gold nanoparticles (AuNPs) show unique size-and shape-dependent photosensitive properties resulting from localized surface plasmon resonance, which can be exploited in colorimetric sensors. Polyamidoamine (PAMAM) dendrimers are suitable nanotemplates of AuNPs and nanoplatforms of some stimuli-responsive materials. In this study, AuNP was loaded in phenylalanine (Phe)-modified PAMAM dendrimers with dual pH-and temperature-sensitive properties to produce a naked-eye colorimetric sensor with responsivity to both pH and temperature. The ultraviolet-visible (UV-Vis) spectra of AuNP-loaded PAMAM-Phe-Suc were changed by heating at pH 4 and 5, but unchanged at pH above 5.5. The UV-Vis spectra of AuNP-loaded PAMAM-Phe and PAMAM-Suc were only slightly changed by heating at pH above 5.5 and at pH 4 and 5, respectively. In solution, AuNP-loaded PAMAM-Phe-Suc changed color (from brown to gray) under high temperature (� 50 °C) and acidic (pH � 5) conditions, suggesting its functionality as a naked-eye colorimetric dual pH and temperature sensor.

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Gene Delivery into T‐Cells Using Ternary Complexes of DNA, Lipofectamine, and Carboxy‐Terminal Phenylalanine‐Modified Dendrimers

Kojima¹,

Sawada²,

Nakase³

et al. 2023

Macromolecular Bioscience

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T‐cells play critical roles in various immune reactions, and genetically engineered T‐cells have attracted attention for the treatment of cancer and autoimmune diseases. Previously, it is shown that a polyamidoamine dendrimer of generation 4 (G4), modified with 1,2‐cyclohexanedicarboxylic anhydride (CHex) and phenylalanine (Phe) (G4‐CHex‐Phe), is useful for delivery into T‐cells and their subsets. In this study, an efficient non‐viral gene delivery system is constructed using this dendrimer. Ternary complexes are prepared using different ratios of plasmid DNA, Lipofectamine, and G4‐CHex‐Phe. A carboxy‐terminal dendrimer lacking Phe (G3.5) is used for comparison. These complexes are characterized using agarose gel electrophoresis, dynamic light scattering, and ζpotential measurements. In Jurkat cells, the ternary complex with G4‐CHex‐Phe at a P/COOH ratio of 1/5 shows higher transfection activity than other complexes, such as binary and ternary complexes with G3.5, without any significant cytotoxicity. The transfection efficiency of the G4‐CHex‐Phe ternary complexes decreases considerably in the presence of free G4‐CHex‐Phe and upon altering the complex preparation method. These results suggest that G4‐CHex‐Phe promotes the cellular internalization of the complexes, which is useful for gene delivery into T‐cells.

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Dual pH-sensitive and UCST-type thermosensitive dendrimers: phenylalanine-modified polyamidoamine dendrimers with carboxyl termini

Abstract: We designed carboxyl-terminal Phe-modified PAMAM dendrimers by using various acid anhydrides. These dendrimers exhibited UCST-type thermosensitivity, which was dependent on both pH and the anhydride modifier.

Cited by 18 publications

References 24 publications

pH-Switchable LCST/UCST-type thermosensitive behaviors of phenylalanine-modified zwitterionic dendrimers

pH-Switchable LCST/UCST-type thermosensitive behaviors of phenylalanine-modified zwitterionic dendrimers

A Naked‐eye Colorimetric pH and Temperature Sensor Based on Gold Nanoparticle‐Loaded Stimuli‐Sensitive Dendrimers

Gene Delivery into T‐Cells Using Ternary Complexes of DNA, Lipofectamine, and Carboxy‐Terminal Phenylalanine‐Modified Dendrimers

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