scholarly journals Conformational Stability of Poly (N-Isopropylacrylamide) Anchored on the Surface of Gold Nanoparticles

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 443
Author(s):  
Runmei Li ◽  
Cong Cheng ◽  
Zhuorui Wang ◽  
Xuefan Gu ◽  
Caixia Zhang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Temperature Sensitivity ◽  
Electrostatic Interaction ◽  
Strong Interaction ◽  
Lower Critical Solution Temperature ◽  
Conformational Stability ◽  
Solution Temperature ◽  
Temperature Sensitive ◽  
Critical Solution Temperature ◽  
Temperature Variations

To verify the temperature sensitive failure of poly (N-isopropylacrylamide) (PNIPAM) anchored on the surface of gold nanoparticles (AuNPs), the UV-Vis spectra with temperature variations of the following aqueous solutions respectively containing AuNPs-PNIPAM, Au-PNIPAM/PNIPAM, PNIPAM, in different media (including salt, ethanol, HCl and cetyltrimethylammoniumbromide (CTAB)), were systematically determined. The results indicated that the UV-Vis spectrum of AuNPs-PNIPAM suspension hardly changed even above the Lower Critical Solution Temperature (LCST) of PNIPAM, but that of Au-PNIPAM/PNIPAM sharply increased only in absorbance intensity. A possible mechanism of the failed temperature sensitivity of PNIPAM anchored on the surface of AuNPs was proposed. Being different from free PNIPAM molecules, a strong interaction exists among PNIPAM molecules anchored on the surface of AuNPs, restraining the change in conformation of PNIPAM. The temperature sensitivity of Au-PNIPAM/PNIPAM originates from the free PNIPAM molecules rather than the anchored PNIPAM one. The changing electrostatic interaction could effectively regulate the aggregation behavior of AuNPs-PNIPAM and enhance its sensitivity to temperature.

THERMOSENSITIVE NANOPARTICLES CONJUGATING WITH CD34 ANTIBODY AND ITS SOLUTION PEROPERTIES

2006 ◽  
Vol 18 (05) ◽  
pp. 222-228 ◽  
Author(s):  
CHUN-TE TAO ◽  
TAI-HORNG YOUNG
Keyword(s):  
Controlled Release ◽  
Cloud Point ◽  
Lower Critical Solution Temperature ◽  
Homogeneous Solution ◽  
The Body ◽  
Solution Temperature ◽  
Temperature Sensitive ◽  
Critical Solution Temperature ◽  
Human Cd34 ◽  
Collapse Temperature

Poly N-isopropylacrylamide (PNIPAAm) is a well-known temperature-sensitive polymer. When the temperature is higher than the lower critical solution temperature (LCST), PNIPAAm aquous solution is cloudy (phase separation occurred). In contrast, when the temperature is lower than the LCST, PNIPAAm is soluble in water (a homogeneous solution). The lower critical solution temperature (LCST) in aqueous solution of PNIPAAm was about 32~33°C. We prepared nano-scaled PNIPAAm particles containing carboxylic group on their surfaces by introducing acrylic acid monomer. The carboxylic groups were applied to conjugate with the amino group of the CD34 antibody. This immuno-conjugate can be applied on targeting the human CD34 positive cells, peripheral blood progenitor cells included, for cell purification and drug controlled release. In order to the active responding of controlled release of the conjugate in the body influenced by temperature, we hope to estimate the shifting of the gel-collapse temperature or cloud point of the immuno-conjugates by dynamic light scattering (DLS) and UV absorption. The results show that the gel-collapse temperature of the nano-particle was not significantly affected by the content of AA between 1.5~5 mol%. However, cloud point of the solution was elevated by the conjugation of CD34 antibody to 37°C. When CD34-conjugated particle was subsequently incorporated with recombinant FLT3-ligand, which is a smaller molecule compare to CD34 antibody, cloud point of the solution was not affected.

Key Factors to Prepare Polyelectrolytes Showing Temperature-Sensitive Lower Critical Solution Temperature-type Phase Transitions in Water

2012 ◽  
Vol 65 (1) ◽  
pp. 91 ◽  
Author(s):  
Yuki Kohno ◽  
Hiroyuki Ohno
Keyword(s):  
Phase Transition ◽  
Lower Critical Solution Temperature ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Phase Behaviour ◽  
Solution Temperature ◽  
Temperature Sensitive ◽  
Key Factors ◽  
Critical Solution Temperature ◽  
Type Phase

Tetrabutylphosphonium styrenesulfonate and its homopolymer showed a lower critical solution temperature-type phase transition in water. As the hydrophobicity of these monomeric and polymeric salts affects phase behaviour, the phase transition temperature of the polyelectrolyte was changed by the introduction of monomers having different alkyl chain length on the phosphonium cations.

Lower critical solution temperature sensitivity to structural changes in poly( N ‐isopropyl acrylamide) homopolymers

2019 ◽  
Vol 57 (20) ◽  
pp. 1386-1393 ◽  
Author(s):  
Alberto García‐Peñas ◽  
Yu Wang ◽  
Alexandra Muñoz‐Bonilla ◽  
Marta Fernández‐García ◽  
Florian J. Stadler
Keyword(s):  
Temperature Sensitivity ◽  
Lower Critical Solution Temperature ◽  
Structural Changes ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Isopropyl Acrylamide

Temperature-Driven and Reversible Assembly of Homopolyelectrolytes Derived from Suitably Designed Ionic Liquids in Water

2013 ◽  
Vol 66 (11) ◽  
pp. 1393 ◽  
Author(s):  
Yuki Kohno ◽  
Yuki Deguchi ◽  
Naomi Inoue ◽  
Hiroyuki Ohno
Keyword(s):  
Ionic Liquids ◽  
Phase Change ◽  
Lower Critical Solution Temperature ◽  
Solution Temperature ◽  
Temperature Sensitive ◽  
Spherical Nanoparticles ◽  
Critical Solution Temperature ◽  
Type Phase ◽  
Diameter Change

Polycationic-type homopolymers derived from polymerisable ionic liquids with adequate hydrophobicity were prepared to form spherical nanoparticles in water that changed their diameter as a function of temperature. The diameter change was attributed to a temperature-sensitive and reversible lower critical solution temperature-type phase change of the polymers in water.

A polyelectrolyte-containing copolymer with a gas-switchable lower critical solution temperature-type phase transition

2019 ◽  
Vol 10 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Jin-Jin Li ◽  
Yin-Ning Zhou ◽  
Zheng-Hong Luo ◽  
Shiping Zhu
Keyword(s):  
Phase Transition ◽  
Cloud Point ◽  
Lower Critical Solution Temperature ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Type Phase

A polyelectrolyte-containing copolymer with a CO2/N2-switchable cloud point, resulting from the gas-induced alternation of hydrophilicity, was prepared.

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