Direct Electrochemical Sensing of Phosphate in Aqueous Solutions Based on Phase Transition of Calcium Phosphate

ACS Sensors ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 541-548 ◽  
Author(s):  
Shuquan Sun ◽  
Qixuan Chen ◽  
Sujitraj Sheth ◽  
Guoxia Ran ◽  
Qijun Song
Keyword(s):  
Phase Transition ◽  
Calcium Phosphate ◽  
Aqueous Solutions ◽  
Electrochemical Sensing

scholarly journals Calcium phosphate phase transition in the presence of Aminosilane

2014 ◽  
Vol 70 (a1) ◽  
pp. C67-C67
Author(s):  
Babak Mostaghaci ◽  
Brigitta Loretz ◽  
Robert Haberkorn ◽  
Guido Kickelbick ◽  
Claus-Michael Lehr
Keyword(s):  
Phase Transition ◽  
Calcium Phosphate ◽  
Blood Compatibility ◽  
Transfection Efficiency ◽  
Hek293 Cells ◽  
Step Method ◽  
Calcium Phosphate Nanoparticles ◽  
Amine Groups ◽  
The Impact

Calcium phosphate has been the point of interest for in vitro gene delivery for many years because of its biocompatibility and straight forward application. However, there are some limitations regarding in vivo administration of these particles mostly because of vast agglomeration of the particles and lack of strong bond between the particles and pDNA. We introduced a simple single step method to functionalize calcium phosphate nanoparticles with Aminosilanes having a different number of amine groups. The nanoparticles were characterized chemically and structurally and their toxicity and interaction with pDNA were studied as well. Results revealed that different crystalline phase of calcium phosphate nanoparticles (Brushite and Hydroxyapatite) with a size below 150 nm were prepared, depending on conditions of synthesis and phase, each with a narrow size distribution. The aminosilane agents caused oriented nucleation and growth of crystallites and can decrease the pH for producing hydroxyapatite phase. The phenomenon could be revealed with the presence of anisotropy in the structure of synthesized hydroxyapatite. The number of amine groups in the Aminosilane agent could change the phase transition pH. Brushite particles revealed to have stronger interaction with pDNA mostly because of their higher positive surface charge. Both particles showed blood compatibility and negligible toxicity. Transfection experiment revealed the capability of both brushite and hydroxyapatite particles to transfect A549 and HEK293 cells. The new modified nanoparticles can be stored in a dried state and re-dispersed easily at the time of administration. Moreover, the transfection efficiency is higher in comparison with conventional calcium phosphate. This study showed the impact of presence and type of the modifying agent on the crystal structure and the amount of surface functionalization of nanoparticles, which in consequence influenced their interaction with cells.

Necklace-like microstructure in shallow-quenched aqueous solutions of poly(n-isopropylacrylamide), detected by advanced small-angle neutron scattering methods

Soft Matter ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 671-682 ◽  
Author(s):  
Satoshi Koizumi ◽  
Masahiko Annaka ◽  
Dietmar Schwahn
Keyword(s):  
Phase Transition ◽  
Aqueous Solutions ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Volume Phase Transition ◽  
Volume Phase ◽  
Isopropyl Acrylamide

The microstructure of aqueous poly(N-isopropyl acrylamide) (PNIPA) gel and solution was investigated by small-angle neutron scattering (SANS) in the vicinity of the gel volume phase transition at TV (= 34 °C).

Aqueous solutions of poly(ethyloxazoline) and its lower consolute phase transition

1990 ◽  
Vol 23 (21) ◽  
pp. 4688-4695 ◽  
Author(s):  
F. P. Chen ◽  
A. E. Ames ◽  
L. D. Taylor
Keyword(s):  
Phase Transition ◽  
Aqueous Solutions

Unusual liquid–liquid phase transition in aqueous mixtures of a well-known dendrimer

2015 ◽  
Vol 17 (43) ◽  
pp. 28818-28829 ◽  
Author(s):  
Viviana C. P. da Costa ◽  
Onofrio Annunziata
Keyword(s):  
Phase Transition ◽  
Phase Separation ◽  
Liquid Phase ◽  
Aqueous Solutions ◽  
Salt Concentration ◽  
High Salt Concentration ◽  
Aqueous Mixtures ◽  
Liquid Phase Transition ◽  
Low Salt ◽  
Liquid Liquid Phase Separation

Salt induces liquid–liquid phase separation (LLPS) of the aqueous solutions of a dendrimer. LLPS occurs by cooling at low salt concentration and by heating at high salt concentration.

scholarly journals Microwave-assisted synthesis of calcium phosphate nanowhiskers

2004 ◽  
Vol 19 (6) ◽  
pp. 1876-1881 ◽  
Author(s):  
Sahil Jalota ◽  
A. Cuneyt Tas ◽  
Sarit B. Bhaduri
Keyword(s):  
Calcium Phosphate ◽  
Aqueous Solutions ◽  
Tricalcium Phosphate ◽  
Room Temperature ◽  
Single Phase ◽  
Microwave Oven ◽  
Molten Salt Synthesis ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Auto Ignition

Calcium phosphate [single-phase hydroxyapatite (HA), single-phase tricalcium phosphate (TCP), and biphasic HA-TCP] nanowhiskers and/or powders were produced by using a novel microwave-assisted “combustion synthesis (auto ignition)/molten salt synthesis” hybrid route. This work is an example of our “synergistic processing” philosophy combining these three technologies while taking advantage of their useful aspects. Aqueous solutions containing NaNO3, Ca(NO3)2·4H2O and KH2PO4 (with or without urea) were irradiated in a household microwave oven for 5 min at 600 watts of power. The as-synthesized precursors were then simply stirred in water at room temperature for 1 h to obtain the nanowhiskers or powders of the desired calcium phosphate bioceramics.

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