Thermo- and pH-induced self-assembly of P(AA-<i>b</i>
-NIPAAm-<i>b</i>
-AA) triblock copolymers synthesized via RAFT polymerization

Kuo, Chung‐Wen; Don, Trong‐Ming; Hsu, Shih-Hsin; Lee, Chia‐Fen; Chiu, Wen‐Yen; Huang, Chih Yuan

doi:10.1002/pola.27950

Cited by 15 publications

(12 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A detailed literature evaluation shows that the CSTs, usually but incorrectly claimed as LCSTs, for aqueous solutions of PNIPAAm were reported even as low as 24 °C and as high as around 60–70 °C . As shown by a variety of typical examples in Table S1 (Supporting Information), the thermal transition temperatures of PNIPAAm homopolymers lie between these data, and even a quick look at this dataset induces significant uncertainties due to the reliability of the reported so‐called LCST values of PNIPAAm in the literature, and other thermally responsive polymers as well, on the one hand . On the other hand, it can also be seen in Table S1 (Supporting Information) that a vari...…”

Section: Introductionmentioning

confidence: 99%

The Dependence of the Cloud Point, Clearing Point, and Hysteresis of Poly(N-isopropylacrylamide) on Experimental Conditions: The Need for Standardization of Thermoresponsive Transition Determinations

Osváth

Iván

2016

Macromol. Chem. Phys.

View full text Add to dashboard Cite

Inappropriately, the critical solution temperature (CST) of lower CST(LCST)‐ or upper CST(UCST)‐type thermoresponsive polymers, measured by one, individual set of conditions, is considered almost exclusively as the LCST or UCST, respectively. These are correctly the minimum or maximum, respectively, of the full phase diagrams. Because the dynamic phase transition depends on the conditions, and no standardized or widely accepted process exists for CST determination, systematic investigations are carried out with the most widely investigated poly(N‐isopropylacrylamide) (PNIPAAm) to unveil the effect of data evaluation, measurement conditions on the transmittance–temperature curves, cloud point (TCP), clearing point (TCL), and heating–cooling hysteresis. The unusual dependence of the fundamental hysteresis parameters, i.e., width of hysteresis (XH) and extent of transmittance recovery (YH), on a broad range of conditions is revealed for the first time. On the basis of the findings, the inflection point of transmittance(absorbance)–temperature curves as TCP and TCL, 0.1 wt% solution, 0.2 °C min−1 heating/cooling steps with 5 min equilibration between the gradual change of temperature, 488 nm wavelength to obtain data comparable to light scattering at this wavelength, and determination of XH and YH are proposed as standard set of conditions.

show abstract

Section: Introductionmentioning

confidence: 99%

The Dependence of the Cloud Point, Clearing Point, and Hysteresis of Poly(N-isopropylacrylamide) on Experimental Conditions: The Need for Standardization of Thermoresponsive Transition Determinations

Osváth

Iván

2016

Macromol. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Poly( N -isopropylacrylamide) (PNIPAAm) is a thermoresponsive polymer that exhibits a conformational change at a lower critical solution temperature (LCST) around 32 °C. Especially, PNIPAAm-based drug delivery systems with thermo- and/or pH-responsive properties have been developed by different methods. − Our previously prepared nanogels based on poly(AA- co -NIPAAm) copolymers have temperature and/or pH-responsive properties. − However, the application of the poly(AA- co -NIPAAm) nanogels for anticancer drug delivery was limited due to its high solubility in physiological saline, leading to fast release of loaded drugs from the carriers during circulating in blood. Our previous study also prepared protamine-based nanoparticles that have enzyme-responsive and charge conversion properties .…”

Section: Introductionmentioning

confidence: 99%

Temperature/pH/Enzyme Triple-Responsive Cationic Protein/PAA-b-PNIPAAm Nanogels for Controlled Anticancer Drug and Photosensitizer Delivery against Multidrug Resistant Breast Cancer Cells

Don

Lin

et al. 2017

Mol. Pharmaceutics

Self Cite

View full text Add to dashboard Cite

The tumor microenvironments are often acidic and overexpress specific enzymes. In this work, we synthesized a poly(AA-b-NIPAAm) copolymer (PAA-b-PNIPAAm) using a reversible addition-fragmentation chain transfer (RAFT) polymerization method. PAA-b-PNIPAAm and a cationic protein (protamine) were self-assembled into nanogels, which effectively reduced the cytotoxicity of protamine. The protamine/PAA-b-PNIPAAm nanogels were responsive to the stimuli including temperature, pH, and enzyme due to disaggregation of PAA-b-PNIPAAm, change in random coil/α-helix conformation of protamine, and enzymatic hydrolysis of the protein. Changing the pH from 7.4 to a lowered pHe (6.5-5.0) resulted in an increase in mean particle size and smartly converted surface charge from negative to positive. The cationic nanogels easily passed through the cell membrane and enhanced intracellular localization and accumulation of doxorubicin-loaded nanogels in multidrug resistant MCF-7/ADR breast cancer cells. Cold shock treatment triggered rapid intracellular release of doxorubicin against P-glycoprotein (Pgp)-mediated drug efflux, showing significantly improved anticancer efficacy as compared with free DOX. Furthermore, the nanogels were able to carry a rose bengal photosensitizer and caused significant damage to the multidrug resistant cancer cells under irradiation. The cationic nanogels with stimuli-responsive properties show promise as drug carrier for chemotherapy and photodynamic therapy against cancers.

show abstract

“…PNIPAAm is a hydrophilic polymer due to its amide side chain hydration in water at ambient temperature. Depend on the degree of dehydration, it becomes more hydrophobic and precipitates from solution by increasing temperature . Note that, H‐bonding between amide–water (hydration) and amide–amide (dehydration) have potential role in this phase transition behavior.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of dual thermo‐ and pH‐sensitive poly(N‐isopropylacrylamide‐co‐acrylic acid)‐grafted cellulose nanocrystals by reversible addition‐fragmentation chain transfer polymerization

Zeinali

Haddadi‐Asl

Roghani‐Mamaqani

2017

J Biomedical Materials Res

View full text Add to dashboard Cite

Free and cellulose nanocrystals (CNCs)-grafted block copolymers of acrylic acid and N-isopropylacrylamide with various poly(N-isopropylacrylamide) (PNIPAAm) block lengths as dual temperature-and pH-sensitive materials were synthesized by reversible addition-fragmentation chain transfer polymerization via an R-approach method. Controlling lower critical solution temperature (LCST) of the products by changing the PNIPAAm block length, addition of CNC, and variation of pH was studied. The free and CNC-grafted block copolymers were analyzed by Fourier transform infrared and proton nuclear magnetic resonance. LCST of copolymers was measured by dynamic light scattering using their hydrodynamic diameters. The block copolymers reversibly form corecorona structure with PNIPAAm as core and poly(acrylic acid) (PAA) as shell above LCST at higher pH values. LCST point shifts to higher temperatures by increasing pH and CNC content and also lowering PNIPAAm block length. By decreasing pH below 4 at certainly low temperatures, PAA becomes core and PNIPAAm forms corona. Thermal behavior of the CNCgrafted polymers was studied by thermal gravimetric analysis and differential scanning calorimetry. Morphology of the polymer-grafted CNC was examined by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy.

show abstract

Thermo- and pH-induced self-assembly of P(AA-b -NIPAAm-b -AA) triblock copolymers synthesized via RAFT polymerization

Cited by 15 publications

References 29 publications

The Dependence of the Cloud Point, Clearing Point, and Hysteresis of Poly(N-isopropylacrylamide) on Experimental Conditions: The Need for Standardization of Thermoresponsive Transition Determinations

The Dependence of the Cloud Point, Clearing Point, and Hysteresis of Poly(N-isopropylacrylamide) on Experimental Conditions: The Need for Standardization of Thermoresponsive Transition Determinations

Temperature/pH/Enzyme Triple-Responsive Cationic Protein/PAA-b-PNIPAAm Nanogels for Controlled Anticancer Drug and Photosensitizer Delivery against Multidrug Resistant Breast Cancer Cells

Synthesis of dual thermo‐ and pH‐sensitive poly(N‐isopropylacrylamide‐co‐acrylic acid)‐grafted cellulose nanocrystals by reversible addition‐fragmentation chain transfer polymerization

Contact Info

Product

Resources

About