scholarly journals Synthesis of Novel pH-Tunable Thermoresponsive Hydroxyl-Terminated Hyperbranched Polyether

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 895
Author(s):  
Xiuzhong Zhu ◽  
Xiao Duan ◽  
Ting Bai ◽  
Xuan Zhang ◽  
Tong Wang ◽  
...  
Keyword(s):  
Light Scattering ◽  
Ph Value ◽  
Click Reaction ◽  
A549 Cells ◽  
Size Exclusion ◽  
Solution Ph ◽  
One Pot ◽  
Vis Spectroscopy ◽  
Hyperbranched Polyether

In this study, a new pH-tunable thermoresponsive hydroxyl-terminated hyperbranched polyether (HTHP 2) was successfully prepared via a one-pot cationic polymerization technique and postmodification. In the first step, hydroxyl-terminated hyperbranched polyether containing double bonds (HTHP 1) were synthesized. Then, through thiol-ene “click” reaction, pH-responsive carboxyl groups were introduced to the target polymer of HTHP 2. The products were characterized via Fourier-transform infrared spectra (FTIR), nuclear magnetic resonance (NMR), and size-exclusion chromatography-multiangle laser light scattering (SEC-MALLS). Moreover, dynamic light scattering (DLS) and UV–Vis spectroscopy was employed to study the pH- and thermoresponsiveness in detail. Results showed that HTHP 2 possessed typical pH-controllable thermoresponsive behavior. By regulating the solution pH value range 3.0–5.4, LCST of HTHP 2 could be changed from 12.8 to 68.0 °C. Meanwhile, the cell viabilities of A549 cells were more than 80% for in vitro cytotoxicity tests of HTHP 2, suggested that HTHP 2 polymers are of good biocompatibility for up to 24 h.

scholarly journals 4-n-Butylresorcinol-Based Linear and Graft Polymethacrylates for Arbutin and Vitamins Delivery by Micellar Systems

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 330 ◽  
Author(s):  
Justyna Odrobińska ◽  
Łukasz Mielańczyk ◽  
Dorota Neugebauer
Keyword(s):  
Click Reaction ◽  
Skin Condition ◽  
Amphiphilic Copolymers ◽  
Solution Ph ◽  
Polymeric Systems ◽  
Micellar Systems ◽  
Poly Ethylene ◽  
Positive Effect ◽  
Active Substances

A novel initiator, bromoester modified 4-n-butylresorcinol (4nBREBr2), was prepared and utilized in controlled atom transfer radical polymerization (ATRP) to obtain three series of amphiphilic copolymers. The V-shaped copolymers of methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), and poly(ethylene glycol) methyl ether methacrylate (MPEGMA), abbreviated to P(HEMA–co–MMA), P(HEMA–co–MPEGMA), and P(MMA–co–MPEGMA), were synthesized. Moreover, P((HEMA–graft–PEG)–co–MMA) graft copolymers were prepared by combining the pre-polymerization modification of HEMA and a “click” reaction using a “grafting onto” approach. All copolymers could form micelles with encapsulated active substances (vitamin C (VitC), vitamin E (VitE), arbutin (ARB)), which are used in cosmetology. In vitro studies carried out in a PBS solution (pH 7.4) demonstrates that in most cases the maximum release of active substance was after 1 h. The polymeric systems presenting satisfactory encapsulation characteristics and release profiles are attractive micellar carriers of cosmetic substances, which show a positive effect on the skin condition.

scholarly journals Ultrasonic-Assisted Extraction, Structural Characterization, Chain Conformation, and Biological Activities of a Pectic-Polysaccharide from Okra (Abelmoschus esculentus)

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1155 ◽  
Author(s):  
Xi-Rui Nie ◽  
Yuan Fu ◽  
Ding-Tao Wu ◽  
Ting-Ting Huang ◽  
Qin Jiang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Chain Conformation ◽  
Size Exclusion ◽  
Pectic Polysaccharide ◽  
Assisted Extraction ◽  
Ultrasonic Assisted ◽  
Pharmaceutical Industries ◽  
Ultrasonic Assisted Extraction

The purpose of this study was to better understand the chemical characteristics and chain conformation of okra polysaccharides extracted by ultrasonic-assisted extraction. A pectic-polysaccharide, named OPP-D, was obtained, which was mainly composed of rhamnose, galacturonic acid, and galactose with a molar ratio of 1.01:1.00:2.31. Combined with NMR analysis, -4)-α-d-GalAp-(1,2,4)-α-l-Rhap-(1- were identified as the backbone with galactan side chains substituted partly at O-4 of Rhap. Molecular weight and radius of gyration of OPP-D were determined as 2.19 × 105 Da and 27.0 nm, respectively. OPP-D was determined as an air-core sphere with branching chains in 0.9% NaCl solution by high-performance size-exclusion chromatography coupled with multi-angle laser light scattering and dynamic light scattering for the first time. Moreover, OPP-D exhibited typical shear-thinning behavior. In addition, OPP-D exhibited remarkable in vitro antioxidant activities and prebiotic activities, while the relatively high molecular weight, high degree of esterification, high content of uronic acids, and highly branched globular conformation of OPP-D might contribute to its in vitro anti-diabetic activities and binding capacities. Results can contribute to a better understanding of the structure–bioactivity relationship of OPPs, and OPP-D has great potential applications in the functional food and pharmaceutical industries.

scholarly journals Photo- and Acid-Degradable Polyacylhydrazone–Doxorubicin Conjugates

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2461
Author(s):  
Maria Psarrou ◽  
Martha Georgia Kothri ◽  
Maria Vamvakaki
Keyword(s):  
Adipic Acid ◽  
Main Chain ◽  
Uv Light ◽  
Attenuated Total Reflection ◽  
Size Exclusion ◽  
Proton Nuclear Magnetic Resonance ◽  
Solution Ph ◽  
Alternating Copolymer ◽  
Vis Spectroscopy ◽  
Self Assembled

Light-mediated polymer degradation has attracted considerable attention in various applications, including photo-patterning, tissue engineering and photo-triggered drug delivery. In this study, we report the synthesis and characterization of a new, linear, main-chain photo- and acid-degradable copolymer based on acylhydrazone linkages. The polymer was synthesized via a step-growth copolymerization of adipic acid dihydrazide with a bifunctional poly(ethylene glycol) bearing benzaldehyde end-groups, under mild acidic conditions, to afford a hydrophilic PEG-alt-adipic acid (PEG-alt-AA) alternating copolymer. The synthesized polymer was characterized by size exclusion chromatography, proton nuclear magnetic resonance and attenuated total reflection-Fourier transform infrared spectroscopies. The main-chain photo- and acid-induced degradation of the copolymer in dimethylsulfoxide and water, respectively, was verified by UV-vis spectroscopy at light intensities as low as 0.1 mW cm−2 at λ = 254 nm. Next, a model anticancer drug, doxorubicin (DOX), was chemically linked to the polymer chain end(s) via acylhydrazone bond(s), resulting in amphiphilic PEG-alt-adipic acid-DOX (PEG-alt-AA-DOX) polymer–drug conjugates. The conjugates were self-assembled in water to form spherical nanoparticles, as evidenced by scanning and transmission electron microscopies. The irradiation of the self-assembled PEG-alt-AA-DOX conjugates with UV light and the decrease of the solution pH resulted in the disruption of the assemblies due to the photolysis and acidolysis of the acylhydrazone bonds, and the release of the therapeutic cargo.

scholarly journals Melanogenesis Using Tyrosinate (Not Tyrosinase)

2018 ◽  
Author(s):  
Koen Vercruysse ◽  
Nahfisa Richardson
Keyword(s):  
Large Scale ◽  
Culture Media ◽  
Disodium Salt ◽  
Size Exclusion ◽  
Future Research ◽  
Vis Spectroscopy ◽  
Set Up ◽  
Mediated Oxidation

<p>We present our initial observations regarding the effect of the presence of L-tyrosinate (= L-tyrosine disodium salt) on the auto- or Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub>-mediated oxidation of various catecholic substances into melanin-like pigments. We observed that L-tyrosinate inhibited the Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub>-mediated oxidation. In contrast, L-tyrosinate promoted the auto-oxidation of ortho-diphenols like L-DOPA, dopamine, epinephrine, norepinephrine, catechol or pyrogallol, but not a meta-diphenol like resorcinol. In addition, we briefly demonstrated the melanogenic properties of cell culture media containing L-tyrosinate. The reactions were monitored using UV-Vis spectroscopy and size exclusion chromatography. For a reaction between L-tyrosinate and L-DOPA, a large scale experiment was set up allowing us to isolate, purify and characterize using FT-IR spectroscopy the melanin-like material obtained. We discuss our observations in the context of the <i>in vitro</i> and <i>in vivo</i> study of melanogenesis and provide some directions for future research efforts.<i></i></p>

scholarly journals Superstructures of fluorescent cyclodextrin via click-reaction

2013 ◽  
Vol 9 ◽  
pp. 827-831 ◽  
Author(s):  
Arkadius Maciollek ◽  
Helmut Ritter ◽  
Rainer Beckert
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Flow Field ◽  
Click Reaction ◽  
Field Flow Fractionation ◽  
Asymmetric Flow ◽  
H Nmr ◽  
Intermolecular Complexes ◽  
Vis Spectroscopy ◽  
Polymeric Structures

Mono-(6-azido-6-deoxy)-β-cyclodextrin (CD) was covalently attached to an alkyne-modified 5-methyl-2-(pyridin-2-yl)thiazol-4-ol yielding a fluorophore containing CD in a click-type reaction. Intermolecular complexes were formed by poly(host–guest)-interactions. The supramolecular structures were characterized by 1H NMR-ROESY spectroscopy, dynamic light scattering, UV–vis spectroscopy, fluorescence spectroscopy, and asymmetric flow field-flow fractionation. By adding potassium adamantane-1-carboxylate, the thiazol dye is displaced from the CD-cavity and the elongated noncovalent polymeric structures collapse.

scholarly journals Key Factors for A One-Pot Enzyme Cascade Synthesis of High Molecular Weight Hyaluronic Acid

2019 ◽  
Vol 20 (22) ◽  
pp. 5664 ◽  
Author(s):  
Gottschalk ◽  
Zaun ◽  
Eisele ◽  
Kuballa ◽  
Elling
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
Pasteurella Multocida ◽  
Ph Value ◽  
Key Factors ◽  
One Pot ◽  
Data Set ◽  
In Vitro Synthesis ◽  
Enzyme Cascade

In the last decades, interest in medical or cosmetic applications of hyaluronic acid (HA) has increased. Size and dispersity are key characteristics of biological function. In contrast to extraction from animal tissue or bacterial fermentation, enzymatic in vitro synthesis is the choice to produce defined HA. Here we present a one-pot enzyme cascade with six enzymes for the synthesis of HA from the cheap monosaccharides glucuronic acid (GlcA) and N-acetylglucosamine (GlcNAc). The combination of two enzyme modules, providing the precursors UDP–GlcA and UDP–GlcNAc, respectively, with hyaluronan synthase from Pasteurella multocida (PmHAS), was optimized to meet the kinetic requirements of PmHAS for high HA productivity and molecular weight. The Mg2+ concentration and the pH value were found as key factors. The HA product can be tailored by different conditions: 25 mM Mg2+ and 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid (HEPES)-NaOH pH 8 result into an HA product with high Mw HA (1.55 MDa) and low dispersity (1.05). Whereas with 15 mM Mg2+ and HEPES–NaOH pH 8.5, we reached the highest HA concentration (2.7 g/L) with a yield of 86.3%. Our comprehensive data set lays the basis for larger scale enzymatic HA synthesis.

scholarly journals Temperature Responsive Nanoparticles Based on PEGylated Polyaspartamide Derivatives for Drug Delivery

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 316 ◽  
Author(s):  
Guangyan Zhang ◽  
Xulin Jiang
Keyword(s):  
Drug Delivery ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Click Reaction ◽  
Drug Loading ◽  
In Vitro Cytotoxicity ◽  
Chemical Structures ◽  
Temperature Responsive ◽  
Mean Size

The temperature responsive PEGylated polyaspartamide derivative, denoted as mPEG-PAAHP, was synthesized by the click reaction. FTIR and 1H NMR were adopted to characterize and confirm the chemical structures of the obtained mPEG-PAAHPs. The temperature responsive behavior investigated by transmittance and dynamic light scattering showed that some of the obtained mPEG-PAAHPs exhibited obvious temperature responsiveness and could be used to prepare nanoparticles by quickly heating. Drug paclitaxel can be encapsulated into mPEG-PAAHP based nanoparticles with a high encapsulation efficiency up to 99% (corresponding to a drug loading content of around 9.9%). Dynamic light scattering results showed that the PTX-loaded nanoparticles had a mean size around 80 nm (PDI<0.2) and good stability in PBS with 150 mM ionic strength. In vitro cytotoxicity results showed that mPEG-PAAHP did not show any toxicity to HeLa cells, but the PTX-loaded nanoparticles based on mPEG-PAAHP exhibited obvious anti-cancer activity. Thus, the temperature responsive PEGylated polyaspartamide derivative mPEG-PAAHP may be a promising drug delivery system.

scholarly journals Synthesis and in vitro PDT evaluation of red emission polymer dots (R-CPDs) and pyropheophorbide-α conjugates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Faiza Sajjad ◽  
Yi-Jia Yan ◽  
Davor Margetić ◽  
Zhi-Long Chen
Keyword(s):  
Cancer Cell Line ◽  
Ros Generation ◽  
One Pot ◽  
Red Emission ◽  
Vis Spectroscopy ◽  
Polymer Dots ◽  
Esophageal Cancer Cell ◽  
Esophageal Cancer Cell Line ◽  
Carbon Based

AbstractCarbon based polymer dots have piqued attention of researchers because of excellent biocompatibility, and good solubility. Most of the p-dots are able to generate ROS which is effective for photodynamic therapy for the treatment of cancer while some photosensitizers such as porphyrins possess some drawbacks such as hydrophobicity, and dark toxicity. Therefore in this study we conjugated red emission carbon based polymer with pyropheophorbide-α through amide condensation and π–π stacking. One pot synthesis of the conjugate was successfully achieved. Their photophysiological properties were studied and structures were characterized by FT-IR, TEM and 1HNMR. pH- sensitivity of the conjugates was confirmed using fluorescence and UV–vis spectroscopy. Photo toxicity and dark toxicity of the prepared conjugates were evaluated in human esophageal cancer cell line (Eca-109). Hemocompatibility of the synthesized conjugates was evaluated and proved that the conjugates are safe to use for the treatment of tumor. Our results showed the PS doped p-dots had less dark toxicity and increased light toxicity as well as ROS generation was high as compared to precursor drug. Therefore, incorporation of p-dots to porphyrin improved biocompatibility and enhanced the photodynamic effect.

scholarly journals One Pot Synthesis of Schiff Base Complexes of Cu(II), Zn(II), Ni(II), Co(II) and their Cytotoxicity, Molecular Docking and Antibacterial Activity

2020 ◽  
Vol 32 (10) ◽  
pp. 2507-2514
Author(s):  
A. Ashma ◽  
A. Sudha ◽  
S.L. Ashok Kumar ◽  
G. Sasikumar ◽  
S.J. Askar Ali
Keyword(s):  
Schiff Base ◽  
Cell Line ◽  
Atomic Ratio ◽  
Schiff Base Complexes ◽  
One Pot ◽  
Human Carcinoma ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Cancer Activity

A novel Schiff base ligand (L), N(4)-cyclohexyl-2-(1-(5-chlorothiophen-2-yl)ethylidene)hydrazine carbothioamide was synthesized from isothiocyanatocyclohexane and hydrazine. All the synthesized transition metal(II) complexes were characterized by functional peak using 1H NMR, 13C NMR, FT-IR, UV-vis spectroscopy and metal complex atomic ratio of complexes of thiosemicarbazones were characterized by elemental analysis. Schiff base and its metal(II) complexes were screened in vitro medicinal drug activity against Gram positive and Gram-negative microorganisms and anti-cancer activity against human carcinoma cell line MCF-7 was detected with nickel(II) and cobalt(II) complexes. Further, the cytotoxity of ligand and its metal(II) complexes were tested on a Monkeys normal cell line and found to be non-toxic (< 200 μg/mL). In the present work, the molecular mechanism of anticancer (breast cancer) activity of the compounds were also disscussed.

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