UV LED Curing Formulation for Polyacrylamide Hydrogels

2015 ◽  
Vol 1125 ◽  
pp. 84-88
Author(s):  
Nur Farizah Ayub ◽  
Shahrir Hashim ◽  
Jamarosliza Jamaluddin ◽  
Roshafima Rasit Ali ◽  
Nadia Adrus

Current studies showed that UV LED system is a green technology and highly efficient as compared to UV Mercury (UV Hg) system. In this study, the UV LED curing formulations of polyacrylamide (PAAm) hydrogels were developed. The formulations consisted of acrylamide (AAm) as a main monomer,N,N’-methylenebisacrylamide as a crosslinker and photoinitiator. UV LED emits monochromatic light sources only (365 nm or 385 nm). Thus, in order to developed formulation of UV LED curable hydrogels, a suitable water soluble photoinitiator (i.e. λ ~ 365 nm) has to be employed. A commercially available photoinitiator Oligo [2-hydroxy-2-methyl-1-[4-(1-methylvinyl) phenyl] propanone] under the trade name Chivacure 300 (λ ~ 330 nm) was chosen in the first formulations. However, due to limited solubility in water, addition of tetrahydrofuran (THF) at 9.5:0.5 ratio of water/THF was required for Chivacure 300. We also synthesized a photoinitiator based on 2,2-dimethoxy-2-phenyl acetophenone (DMPA) and methylated-β-cyclodextrin (MβCD) to be used in the second formulation. The complexation of DMPA and MβCD resulted in transparent and water-soluble supramolecular-structured photoinitiator (SSPI) (λ ~ 330 nm). Both formulations were irradiated using UV LED system (Hoenle AG, Germany, 365 nm) for 15 min. Synthesis of PAAm hydrogels with both photoinitiators has yielded almost complete conversion of hydrogels (> 80 %). Clearly, this study has revealed that enhanced formulation of UV LED curable hydrogels are due to appropriate choice of excellent water-solubility photoinitiators (Chivacure 300 and modified DMPA). We concluded that UV LED is an important tool for curing hydrogel formulations of various acrylate water-based monomers.

2014 ◽  
Vol 695 ◽  
pp. 102-105 ◽  
Author(s):  
Nur Farizah Ayub ◽  
Shahrir Hashim ◽  
Nadia Adrus

Recent trends show that the UV LED light source can greatly reduce environmental effect without compromising performance as compared to conventional UV mercury-based lamp (UV Hg) system. In this study, the possibility of using UV LED technology for photopolymerization of polyacrylamide (PAAm) hydrogels is presented. This has strongly drives the needs for suitable water-soluble photoinitiator formulation. Specifically, the photoinitiator must possess characteristic wavelength within UV LED range as UV LED emits monochromatic light sources only (365 nm or 385 nm). Here, the commercially available photoinitiator Oligo [2-hydroxy-2-methyl-1-[4-(1-methylvinyl) phenyl] propanone] (Chivacure 300) was chosen. However, Chivacure 300 has limited solubility in water. Hence, addition of tetrahydrofuran (THF) at various ratios was required. The results demonstrated that 9.5:0.5 ratio of water/THF was the minimum ratio needed for the solubility of Chivacure 300. After the synthesis of PAAm hydrogels, almost complete conversion of hydrogels was achieved (> 80 %). The highest conversion was achieved with formulation of Chivacure 300 in 9.5:0.5 ratio of water/THF. At this ratio, the hydrogels obtained were transparent. With increasing ratio of THF in water, the appearance of hydrogels gradually changed to cloudy. Indeed, UV LED technology can be used to polymerize PAAm hydrogels with comparably high conversion to conventional UV Hg system.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 938
Author(s):  
Miguel Meléndez-Zamudio ◽  
Ileana Bravo-Flores ◽  
Eulalia Ramírez-Oliva ◽  
Antonio Guerra-Contreras ◽  
Gilberto Álvarez-Guzmán ◽  
...  

Stone consolidants have been widely used to protect historical monuments. Consolidants and hydrophobic formulations based on the use of tetraethoxysilane (TEOS) and alkylalkoxysilanes as precursors have been widely applied, despite their lack of solubility in water and requirement to be applied in organic media. In the search for a “greener” alternative based on silicon that has potential use in this field, the use of tetrakis(2-hydroxyethyl)silane (THEOS) and tris(2-hydroxyethyl)methyl silane (MeTHEOS) as precursors, due their high water solubility and stability, is proposed in this paper. It is already known that THEOS and MeTHEOS possess remarkable compatibility with different natural polysaccharides. The investigated approach uses the water-soluble silanes THEOS–chitosan and MeTHEOS–chitosan as a basis for obtaining hybrid consolidants and hydrophobic formulations for the conservation of siliceous and calcareous stones. In the case of calcareous systems, their incompatibility with alkoxysilanes is known and is expected to be solved by the developed hybrid consolidant. Their application in the conservation of building stones from historical and archeological sites from Guanajuato, México was studied. The evaluation of the consolidant and hydrophobic formulation treatment was mainly conducted by determining the mechanical properties and contact angle measurements with satisfactory results in terms of the performance and compatibility with the studied stones.


2021 ◽  
Vol 37 (6) ◽  
pp. 533-542
Author(s):  
Florencia Anabel Mesas ◽  
María Cecilia Terrile ◽  
María Ximena Silveyra ◽  
Adriana Zuñiga ◽  
María Susana Rodriguez ◽  
...  

Chitosan has been considered an environmental-friendly polymer. However, its use in agriculture has not been extended yet due to its relatively low solubility in water. N-Methylene phosphonic chitosan (NMPC) is a water-soluble derivative prepared by adding a phosphonic group to chitosan. This study demonstrates that NMPC has a fungicidal effect on the phytopathogenic fungus Fusarium solani f. sp. eumartii (F. eumartii) judged by the inhibition of F. eumartti mycelial growth and spore germination. NMPC affected fungal membrane permeability, reactive oxygen species production, and cell death. Also, this chitosan-derivative exerted antifungal effects against two other phytopathogens, Botrytis cinerea, and Phytophthora infestans. NMPC did not affect tomato cell viability at the same doses applied to these phytopathogens to exert fungicide action. In addition to water solubility, the selective biological cytotoxicity of NMPC adds value in its application as an antimicrobial agent in agriculture.


Author(s):  
Wiktoria Tomal ◽  
Joanna Ortyl

Light-initiated polymerization processes are currently an important tool in various industrial fields. The advancement of technology has resulted in the use of photopolymerization in various biomedical applications, such as the production of 3D hydrogel structures, the encapsulation of cells, and in drug delivery systems. The use of photopolymerization processes requires an appropriate initiating system which, in biomedical applications, must meet additional criteria: high water solubility, non-toxicity to cells, and compatibility with visible low-power light sources. This article is a literature review on those compounds that act as photoinitiators of photopolymerization processes in biomedical applications. The division of initiators according to the method of photoinitiation was described and the related mechanisms were discussed. Examples from each group of photoinitiators are presented, and their benefits, limitations and applications are outlined.


Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1073 ◽  
Author(s):  
Wiktoria Tomal ◽  
Joanna Ortyl

Light-initiated polymerization processes are currently an important tool in various industrial fields. The advancement of technology has resulted in the use of photopolymerization in various biomedical applications, such as the production of 3D hydrogel structures, the encapsulation of cells, and in drug delivery systems. The use of photopolymerization processes requires an appropriate initiating system that, in biomedical applications, must meet additional criteria such as high water solubility, non-toxicity to cells, and compatibility with visible low-power light sources. This article is a literature review on those compounds that act as photoinitiators of photopolymerization processes in biomedical applications. The division of initiators according to the method of photoinitiation was described and the related mechanisms were discussed. Examples from each group of photoinitiators are presented, and their benefits, limitations, and applications are outlined.


2019 ◽  
Vol 59 (7) ◽  
pp. 37-42
Author(s):  
Anton O. Pozdeev ◽  
◽  
Alexander M. Koroteev ◽  
Sofia N. Pimankina ◽  
Mikhail P. Koroteev ◽  
...  

The flavonoid dihydroquercetin and its esterified derivatives possess various biological activities and are widely used as dietary supplements and in pharmacology. A significant disadvantage of this flavonoid is its low solubility in water at ordinary temperatures of up to 0.03%, which negatively affects its biological activity. Nature overcomes this problem by glycosylation, sulfation, and phosphorylation. In chemistry and pharmacology to overcome this problem, there are several synthetic approaches. For dihydroquercetin (DHQ) is the inclusion of DHQ in the cyclodextrin matrix or the formation of a complex of DHQ with basic natural amino acids. In this paper, a method is proposed for obtaining water-soluble morpholinium salts based on chloroacylated derivatives of DHQ. The acylation reaction was carried out in dioxane, pyridine was used as an acceptor of choric hydrogen. The target compounds were obtained with a yield of 68-79%. As a result, chlorinated derivatives based on DHQ and its acyl and benzyl derivatives were synthesized. These derivatives in the interaction with morpholine form its salts, which, as it turned out, have a high water solubility. Pentamorpholine salt of DHQ had the highest solubility in water, up to 6.5% at room temperature, which is 200 times more soluble than the original DHQ. The proposed synthetic approach to increase the water solubility of acyl derivatives of DHQ can be extended using other nitrogenous bases and other haloacyl derivatives of DHQ.


2019 ◽  
Author(s):  
Jenna Franke ◽  
Benjamin Raliski ◽  
Steven Boggess ◽  
Divya Natesan ◽  
Evan Koretsky ◽  
...  

Fluorophores based on the BODIPY scaffold are prized for their tunable excitation and emission profiles, mild syntheses, and biological compatibility. Improving the water-solubility of BODIPY dyes remains an outstanding challenge. The development of water-soluble BODIPY dyes usually involves direct modification of the BODIPY fluorophore core with ionizable groups or substitution at the boron center. While these strategies are effective for the generation of water-soluble fluorophores, they are challenging to implement when developing BODIPY-based indicators: direct modification of BODIPY core can disrupt the electronics of the dye, complicating the design of functional indicators; and substitution at the boron center often renders the resultant BODIPY incompatible with the chemical transformations required to generate fluorescent sensors. In this study, we show that BODIPYs bearing a sulfonated aromatic group at the meso position provide a general solution for water-soluble BODIPYs. We outline the route to a suite of 5 new sulfonated BODIPYs with 2,6-disubstitution patterns spanning a range of electron-donating and -withdrawing propensities. To highlight the utility of these new, sulfonated BODIPYs, we further functionalize them to access 13 new, BODIPY-based voltage-sensitive fluorophores. The most sensitive of these BODIPY VF dyes displays a 48% ΔF/F per 100 mV in mammalian cells. Two additional BODIPY VFs show good voltage sensitivity (≥24% ΔF/F) and excellent brightness in cells. These compounds can report on action potential dynamics in both mammalian neurons and human stem cell-derived cardiomyocytes. Accessing a range of substituents in the context of a water soluble BODIPY fluorophore provides opportunities to tune the electronic properties of water-soluble BODIPY dyes for functional indicators.


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1140
Author(s):  
Silvana Alfei ◽  
Gabriella Piatti ◽  
Debora Caviglia ◽  
Anna Maria Schito

The growing resistance of bacteria to current chemotherapy is a global concern that urgently requires new and effective antimicrobial agents, aimed at curing untreatable infection, reducing unacceptable healthcare costs and human mortality. Cationic polymers, that mimic antimicrobial cationic peptides, represent promising broad-spectrum agents, being less susceptible to develop resistance than low molecular weight antibiotics. We, thus, designed, and herein report, the synthesis and physicochemical characterization of a water-soluble cationic copolymer (P5), obtained by copolymerizing the laboratory-made monomer 4-ammoniumbuthylstyrene hydrochloride with di-methyl-acrylamide as uncharged diluent. The antibacterial activity of P5 was assessed against several multi-drug-resistant clinical isolates of both Gram-positive and Gram-negative species. Except for strains characterized by modifications of the membrane charge, most of the tested isolates were sensible to the new molecule. P5 showed remarkable antibacterial activity against several isolates of genera Enterococcus, Staphylococcus, Pseudomonas, Klebsiella, and against Escherichia coli, Acinetobacter baumannii and Stenotrophomonas maltophilia, displaying a minimum MIC value of 3.15 µM. In time-killing and turbidimetric studies, P5 displayed a rapid non-lytic bactericidal activity. Due to its water-solubility and wide bactericidal spectrum, P5 could represent a promising novel agent capable of overcoming severe infections sustained by bacteria resistant the presently available antibiotics.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1915 ◽  
Author(s):  
Eyob Wondu ◽  
Hyun Woo Oh ◽  
Jooheon Kim

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).


Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1008 ◽  
Author(s):  
Qilei Yang ◽  
Chang Zu ◽  
Wengang Li ◽  
Weiwei Wu ◽  
Yunlong Ge ◽  
...  

Paclitaxel (PTX) is a poor water-soluble antineoplastic drug with significant antitumor activity. However, its low bioavailability is a major obstacle for its biomedical applications. Thus, this experiment is designed to prepare PTX crystal powders through an antisolvent precipitation process using 1-hexyl-3-methylimidazolium bromide (HMImBr) as solvent and water as an antisolvent. The factors influencing saturation solubility of PTX crystal powders in water in water were optimized using a single-factor design. The optimum conditions for the antisolvent precipitation process were as follows: 50 mg/mL concentration of the PTX solution, 25 °C temperature, and 1:7 solvent-to-antisolvent ratio. The PTX crystal powders were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography–mass spectrometry, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy, solid-state nuclear magnetic resonance, and dissolution and oral bioavailability studies. Results showed that the chemical structure of PTX crystal powders were unchanged; however, precipitation of the crystalline structure changed. The dissolution test showed that the dissolution rate and solubility of PTX crystal powders were nearly 3.21-folds higher compared to raw PTX in water, and 1.27 times higher in artificial gastric juice. Meanwhile, the bioavailability of PTX crystal increased 10.88 times than raw PTX. These results suggested that PTX crystal powders might have potential value to become a new oral PTX formulation with high bioavailability.


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