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1.
BMC Complement Med Ther ; 24(1): 217, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38844985

RESUMO

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory condition characterized by the accumulation of reactive oxygen species and the expression of inflammatory factors. Regarding its anti-atopic activity, numerous traditional medicinal materials and secondary metabolic products play pivotal roles in modulating the associated mechanisms. METHODS: This study aimed to utilize Salvia miltiorrhiza Bunge (SMB) as an anti-AD source. In-vitro activity assessments and qualitative and quantitative analyses using UPLC-TQ-MS/MS and HPLC-DAD were conducted in two cultivars ('Dasan' and 'Kosan'). Statistical analysis indicated that the profiles of their secondary metabolites contribute significantly to their pharmacological properties. Consequently, bio-guided fractionation was undertaken to figure out the distinct roles of the secondary metabolites present in SMB. RESULTS: Comparative study of two cultivars indicated that 'Dasan', having higher salvianolic acid A and B, exhibited stronger antioxidant and anti-inflammatory activities. Meanwhile, 'Kosan', containing higher tanshinones, showed higher alleviating activities on anti-AD related genes in mRNA levels. Additionally, performed bio-guided fractionation re-confirmed that the hydrophilic compounds of SMB can prevent AD by inhibiting accumulation of ROS and suppressing inflammatory factors and the lipophilic components can directly inhibit AD. CONCLUSIONS: SMB was revealed as a good source for anti-AD activity. Several bioactive compounds were identified from the UPLC-TQ-MS/MS and different compounds content was linked to biological activities. Characterization of these compounds may be helpful to understand differential role of secondary metabolites from SMB on alleviation of AD.


Assuntos
Anti-Inflamatórios , Dermatite Atópica , Extratos Vegetais , Salvia miltiorrhiza , Salvia miltiorrhiza/química , Dermatite Atópica/tratamento farmacológico , Extratos Vegetais/farmacologia , Humanos , Anti-Inflamatórios/farmacologia , Espectrometria de Massas em Tandem , Cromatografia Líquida de Alta Pressão , Antioxidantes/farmacologia , Espécies Reativas de Oxigênio/metabolismo
2.
J Nanobiotechnology ; 22(1): 323, 2024 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-38849931

RESUMO

BACKGROUND: The non-toxic self-crosslinked hydrogel films designed from biocompatible materials allow for controlled drug release and have gathered remarkable attention from healthcare professionals as wound dressing materials. Thus, in the current study the chitosan (CS) film is infused with oil-in-water Pickering emulsion (PE) loaded with bioactive compound quercetin (Qu) and stabilized by dialdehyde cellulose nanocrystal-silver nanoparticles (DCNC-AgNPs). The DCNC-AgNPs play a dual role in stabilizing PE and are involved in the self-crosslinking with CS films. Also, this film could combine the advantage of the controlled release and synergistic wound-healing effect of Qu and AgNPs. RESULTS: The DCNC-AgNPs were synthesized using sodium periodate oxidation of CNC. The DCNC-AgNPs were used to stabilize oil-in-water PE loaded with Qu in its oil phase by high speed homogenization. Stable PEs were prepared by 20% v/v oil: water ratio with maximum encapsulation of Qu in the oil phase. The Qu-loaded PE was then added to CS solution (50% v/v) to prepare self-crosslinked films (CS-PE-Qu). After grafting CS films with PE, the surface and cross-sectional SEM images show an inter-penetrated network within the matrix between DCNC and CS due to the formation of a Schiff base bond between the reactive aldehyde groups of DCNC-AgNPs and amino groups of CS. Further, the addition of glycerol influenced the extensibility, swelling ratio, and drug release of the films. The fabricated CS-PE-Qu films were analyzed for their wound healing and tissue regeneration potential using cell scratch assay and full-thickness excisional skin wound model in mice. The as-fabricated CS-PE-Qu films showed great biocompatibility, increased HaCat cell migration, and promoted collagen synthesis in HDFa cells. In addition, the CS-PE-Qu films exhibited non-hemolysis and improved wound closure rate in mice compared to CS, CS-Qu, and CS-blank PE. The H&E staining of the wounded skin tissue indicated the wounded tissue regeneration in CS-PE-Qu films treated mice. CONCLUSION: Results obtained here confirm the wound healing benefits of CS-PE-Qu films and project them as promising biocompatible material and well suited for full-thickness wound healing in clinical applications.


Assuntos
Quitosana , Emulsões , Hidrogéis , Nanopartículas Metálicas , Quercetina , Prata , Pele , Cicatrização , Quercetina/química , Quercetina/farmacologia , Cicatrização/efeitos dos fármacos , Quitosana/química , Animais , Emulsões/química , Camundongos , Humanos , Pele/efeitos dos fármacos , Pele/lesões , Nanopartículas Metálicas/química , Prata/química , Hidrogéis/química , Materiais Biocompatíveis/química , Bandagens , Liberação Controlada de Fármacos , Sistemas de Liberação de Medicamentos/métodos , Celulose/química , Masculino , Regeneração/efeitos dos fármacos , Células HaCaT , Oxirredução , Metilgalactosídeos
4.
RSC Adv ; 14(15): 10653-10661, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38567327

RESUMO

Self-reporting systems automatically indicate damaged or corroded surfaces via color changes or fluorescence. In this study, a novel reusable self-reporting system is developed by exploiting the reversibility of a donor-acceptor Stenhouse adduct (DASA). The synthesized DASA precursor exhibits a color change when damaged upon reaction with diethylamine, and returns to its colorless form upon irradiation with visible light. Microcapsules are synthesized with a core comprising styrene and the DASA precursor, along with a shell formed of urea and formaldehyde. The optimal particle size and shell thickness of the microcapsules are 225 µm and 0.17 µm, respectively. The DASA precursor-containing microcapsules are embedded in a PEG gel matrix with secondary amine groups. This coating system, initially colorless, exhibits a color change, becoming pink after being damaged by scratching due to the reaction between the DASA precursor released from ruptured microcapsules with the secondary amine groups of the PEG gel, thus demonstrating self-reporting characteristics. Furthermore, the colored surface is restored to its initial colorless state by irradiation with visible light for 1.5 hours, demonstrating the reusability of the self-reporting system.

5.
Aging Dis ; 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38607741

RESUMO

The diagnosis, treatment, and management of dementia provide significant challenges due to its chronic cognitive impairment. The complexity of this condition is further highlighted by the impact of gene-environment interactions. A recent strategy combines advanced genomics and precision medicine methods to explore the complex genetic foundations of dementia. Utilizing the most recent research in the field of neurogenetics, the importance of precise genetic data in explaining the variation seen in dementia patients can be investigated. Gene-environment interactions are important because they influence genetic susceptibilities and aid in the development and progression of dementia. Modified to each patient's genetic profile, precision medicine has the potential to detect groups at risk and make previously unheard-of predictions about the course of diseases. Precision medicine techniques have the potential to completely transform treatment and diagnosis methods. Targeted medications that target genetic abnormalities will probably appear, providing the possibility for more efficient and customized medical interventions. Investigating the relationship between genes and the environment may lead to preventive measures that would enable people to change their surroundings and minimize the risk of dementia, leading to the improved lifestyle of affected people. This paper provides a comprehensive overview of the genomic insights into dementia, emphasizing the pivotal role of precision medicine, and gene-environment interactions.

6.
Nucl Med Mol Imaging ; 58(2): 81-85, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38510822

RESUMO

Solid pseudopapillary tumor (SPT) of the pancreas is a neoplasm with low malignant potential. It is often challenging to diagnose SPT due to its nonspecific clinical and radiological features, and [18F]FDOPA is effective in diagnosing SPT, particularly in differentiating SPT from benign conditions such as splenosis. A 55-year-old woman underwent distal pancreatectomy and splenectomy for histologically confirmed SPT. She was also initially diagnosed with splenosis. During follow-up, sizes of multiple nodular lesions were increased, raising the possibility of peritoneal seeding of SPT. For diagnosis, a spleen scan and SPECT/CT were performed using 99mTc-labeled damaged red blood cells, which showed no uptake in the peritoneal nodules. Subsequent [18F]FDOPA PET/CT revealed [18F]FDOPA-avidity of the nodules. The patient underwent tumor resection surgery, and the nodules were pathologically confirmed as SPT.

7.
Adv Healthc Mater ; : e2303480, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38421096

RESUMO

Peptide-drug conjugates (PDCs) are a promising class of drug delivery systems that utilize covalently conjugated carrier peptides with therapeutic agents. PDCs offer several advantages over traditional drug delivery systems including enhanced target engagement, improved bioavailability, and increased cell permeability. However, the development of efficient transcellular peptides capable of effectively transporting drugs across biological barriers remains an unmet need. In this study, physicochemical criteria based on cell-penetrating peptides are employed to design transcellular peptides derived from an antimicrobial peptides library. Among the statistically designed transcellular peptides (SDTs), SDT7 exhibits higher skin permeability, faster kinetics, and improved cell permeability in human keratinocyte cells compared to the control peptide. Subsequently, it is found that 6-Paradol (PAR) exhibits inhibitory activity against phosphodiesterase 4, which can be utilized for an anti-inflammatory PDC. The transcellular PDC (SDT7-conjugated with PAR, named TM5) is evaluated in mouse models of psoriasis, exhibiting superior therapeutic efficacy compared to PAR alone. These findings highlight the potential of transcellular PDCs (TDCs) as a promising approach for the treatment of inflammatory skin disorders.

8.
Nutr Metab (Lond) ; 21(1): 7, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38243227

RESUMO

BACKGROUND: Bone is continuously produced by osteoblasts and resorbed by osteoclasts to maintain homeostasis. Impaired bone resorption by osteoclasts causes bone diseases such as osteoporosis and arthritis. Most pharmacological treatment of osteoporosis focuses on inhibiting osteoclast differentiation, often to restore osteoclast/osteoclast balance. However, recent osteoporosis treatments have various side effects. According to a recent study, resveratrol, known as a stilbenoid family, is known to increase bone density, and the osteoclast inhibitory effect was confirmed using oxyresveratrol, a stilbenoid family. Here, we investigated the effect of oxyresveratrol on osteoclast differentiation and an ovariectomized mouse model. METHODS: Mouse leukemia monocyte/macrophage cell line RAW 264.7 was treated with oxyresveratrol, and cell cytotoxicity was confirmed by measuring MTT assay. Tartrate-resistant acid phosphatase (TRAP), an enzyme marker for osteoclasts, was confirmed by staining. In addition, osteoclast differentiation markers and MAPK-related markers were confirmed at the mRNA level and protein expression. The effect of oxyresveratrol was confirmed using ovariectomized mice. Deoxypyridinoline (DPD) was measured using mouse urine and TRAP activity was observed using serum. Bone mineral density was also measured using Micro-CT. RESULTS: The polyphenol oxyresveratrol inhibited receptor activator of nuclear factor kappa-Β ligand (RANKL)-induced osteoclast differentiation of RAW 264.7 cells. Furthermore, oxyresveratrol inhibited TRAP activity and actin-ring formation. Moreover, oxyresveratrol suppressed the phosphorylation of the RANKL-induced mitogen-activated protein kinases (MAPKs) p38, JNK, and ERK and significantly reduced the expression of bone differentiation markers (NFATc1, cathepsin K, and TRAP). CONCLUSION: Oxyresveratrol inhibits osteoclast differentiation via MAPK and increases bone density in ovariectomized rats, suggesting it has therapeutic potential for bone diseases such as osteoporosis. We confirmed the osteoporosis prevention effect of OR in Raw 264.7 cells, and future studies should confirm the effect of OR using rat bone marrow-derived cells.

9.
J Biomater Appl ; 38(8): 890-904, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38282509

RESUMO

Poly (acrylic acid) (PAA), an anionic polymer was used to prepare ion pair self-assembly (IPSAM) with 4-(methylthio)aniline (MTA), a hydrophobic counter ion, which is responsive to temperature and oxidation. The IPSAM was formed when the carboxylic to amino group molar ratio was 7/3-5/5. The structure of the IPSAM nanoparticle was spherical whose diameter was 30-40 nm on the TEM images. The PAA/MTA ion pair showed the upper critical solution temperature (UCST) that hiked with increasing MTA content. When the MTA of the ion pair was oxidized by H2O2, the UCST was also increased. The amphiphilic property of the ion pair was responsible for interface activity which declined upon the oxidation of the MTA. The surface tension was low for the ratio of PAA/MTA (5/5), which made the 5/5 ratio suitable for further studies. The interaction between PAA and MTA, which was ionic, and the oxidation of MTA was confirmed by FT-IR spectroscopy. The release of payload (i.e. Nile red) in IPSAM was restrained below the UCST but it was triggered above the phase transition temperature possibly due to the disintegration of the IPSAM whereas on MTA oxidation the release was shielded due to more hydrophobicity. The release was found to be higher in tumor environment temperature which could be controlled with the input concentration of H2O2 giving a stable IPSAM. The cell viability results showed that IPSAM has no significant cytotoxicity and can serve as a drug carrier for stimulus-response.


Assuntos
Peróxido de Hidrogênio , Polímeros , Espectroscopia de Infravermelho com Transformada de Fourier , Polímeros/química , Micelas , Portadores de Fármacos , Concentração de Íons de Hidrogênio
10.
RSC Adv ; 14(5): 3560-3566, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38264271

RESUMO

Anti-counterfeiting (ACF) technology plays a crucial role in distinguishing genuine products from counterfeits, as well as in identity verification. Moreover, it serves as a protective measure for safeguarding the rights of individuals, companies, and governments. In this study, a high-level ACF technology was developed using a color-conversion system based on the photothermal effect of near-infrared (NIR) wavelengths. Diimonium dye (DID), which is a photothermal dye, was selected because it is an NIR absorbing dye with over 98% transparency in the visible light (vis) region. Due to the photothermal properties of DID, the temperature increased to approximately 65 °C at 1064 nm and 39 °C at 808 nm, respectively. Additionally, we employed a donor-acceptor Stenhouse adduct dye, a thermochromic dye, which exhibits reversible color change due to heat (red color) and light (colorless). Our ACF technology was applied to the brand-protecting fiber utilizing the difference in photothermal temperature according to the NIR wavelength. We successfully implemented anti-counterfeit clothing using alphabet K labels that could distinguish between genuine and counterfeit products by irradiating with specific NIR wavelengths.

11.
Clin Cosmet Investig Dermatol ; 17: 125-135, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38259431

RESUMO

Background: Skin cooling during laser or radiofrequency (RF) treatments is a method to minimize thermal damage to the epidermis, reduce pain, and decrease post-treatment downtime. We evaluated the effect of parallel contact cooling (PCC) on RF-induced thermal reactions in minipig skin in vivo after bipolar microneedling RF treatment. Methods: RF treatments were administered at frequencies of 0.5, 1, and 2 MHz with single (500 ms), six (1000 ms), and ten (5000 ms) sub-pulse packs to minipig skin with or without PCC. Subsequently, thermometric imaging and histology were used to analyze skin reactions to RF. Results: Thermometric images showed that PCC promptly lowered skin temperature in the RF-treated area, with this effect persisting for over 60s. Regardless of the PCC, RF treatments lasting for 500 ms with a single pulse pack resulted in peri-electrode coagulative necrosis (PECN) zones and inter-electrode non-necrotic thermal reaction (IENT) zones in the dermis. In contrast, treatment lasting 5000 ms with 10 sub-pulse packs produced distinct IENT without notable PECN over a wide dermal area. Skin specimens obtained at 1 h and 3, 7, and 14 days after PCC-assisted RF treatments showed a higher degree of thermal tissue reactions in the deeper dermal regions compared to those after RF treatments without PCC. Conclusion: PCC-assisted RF treatment, utilizing an invasive bipolar microneedling device, enhanced RF-induced skin reactions in the mid to deep dermis while preserving the epidermis and upper papillary dermis from excessive thermal tissue injury.

12.
J Vasc Interv Radiol ; 35(2): 203-212, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37866475

RESUMO

PURPOSE: To evaluate the safety and effectiveness of ablative radioembolization for large hepatocellular carcinoma (HCC) while preserving a small future liver remnant (FLR). MATERIALS AND METHODS: Twenty-five patients with large HCC of ≥5 cm requiring treatment for >60% of the total liver volume and having well-preserved liver function were treated with ablative glass microsphere radioembolization at a single institution from January 2017 to December 2021. Radioembolization was performed with a mean absorbed dose of >150 Gy, and the FLR per nontumor liver volume (NTLV) was set at >30%. Changes in liver function, adverse events, duration of response (DoR) in a treated area, time-to-progression (TTP), and overall survival (OS) were retrospectively investigated. RESULTS: The largest tumor diameter and planned dose per treated volume were 11.4 cm ± 3.9 and 242.3 Gy ± 63.6 (169.4 Gy ± 45.9 per whole liver volume), respectively. All patients remained at Child-Pugh Class A for 90 days. No patient experienced Grade 3‒4 hyperbilirubinemia or new ascites. One patient (lung dose, 27.8 Gy) developed radiation pneumonitis requiring transient steroid treatment. According to the posttreatment dosimetry, the tumorous and nontumorous liver absorbed doses were 418.8 Gy ± 227.4 and 69.0 Gy ± 32.1, respectively. The median DoR in a treated area and TTP were 22.0 and 17.1 months, respectively. The 5-year OS rate was 83.2%. CONCLUSIONS: Ablative radioembolization of large HCC of ≥5 cm can be performed safely and effectively in patients with preserved liver function when FLR/NTLV exceeds 30%.


Assuntos
Carcinoma Hepatocelular , Embolização Terapêutica , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/radioterapia , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/radioterapia , Hepatectomia , Estudos Retrospectivos , Radioisótopos de Ítrio/efeitos adversos , Embolização Terapêutica/efeitos adversos , Microesferas , Resultado do Tratamento
13.
Int J Biol Macromol ; 254(Pt 3): 127984, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37951429

RESUMO

Developing polymeric materials with remarkable mechanical properties and fast self-healing performance even at low temperatures is challenging. Herein, the polymeric nanocomposites containing silane-treated cellulose nanocrystals (SCNC) with ultrafast self-healing and exceptional mechanical characteristics were developed even at low temperatures. First, CNC is modified with a cyclic silane coupling agent using an eco-friendly chemical vapor deposition method. The nanocomposite was then fabricated by blending SCNC with matrix prepolymer, prepared from monomers that possess lower critical solution temperature, followed by the inclusion of dibutyltin dilaurate and hexamethylene diisocyanate. The self-healing capability of the novel SCNC/polymer nanocomposites was enhanced remarkably by increasing the content of SCNC (0-3 wt%) and reaching (≥99 %) at temperatures (5 & 25 °C) within <20 min. Moreover, SCNC-3 showed a toughness of (2498 MJ/m3) and SCNC-5 displayed a robust tensile strength of (22.94 ± 0.4 MPa) whereas SCNC-0 exhibited a lower tensile strength (7.4 ± 03 MPa) and toughness of (958 MJ/m3). Additionally, the nanocomposites retain their original mechanical properties after healing at temperatures (5 & 25 °C) owing to the formation of hydrogen bonds via incorporation of the SCNC. These novel SCNC-based self-healable nanocomposites with tunable mechanical properties offer novel insight into preparing damage and temperature-responsive flexible and wearable devices.


Assuntos
Nanocompostos , Nanopartículas , Temperatura , Silanos , Celulose/química , Polímeros/química , Nanocompostos/química , Nanopartículas/química
14.
ACS Appl Mater Interfaces ; 16(1): 1511-1520, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38129176

RESUMO

Given the substantial environmental challenge posed by global plastic waste, recycling technology for thermosetting polymers has become a huge research topic in the polymer industry. Covalent adaptive networks (CANs), which can reversibly dissociate and reconstruct their network structure, represent a key technology for the self-healing, reprocessing, and recycling of thermosetting polymers. In the present study, we introduce a new series of polyurethane CANs whose network structure can dissociate via the self-catalyzed formation of dithiolane from the CANs' polydisulfide linkages when the CANs are treated in N,N-dimethylformamide (DMF) or dimethyl sulfoxide at 60 °C for 1 h. More interestingly, we found that this network dissociation even occurs in tetrahydrofuran-DMF solvent mixtures with low DMF concentrations. This feature enables a reduction in the use of high-boiling, toxic polar aprotic solvents. The dissociated network structure of the CANs was reconstructed under UV light at 365 nm with a high yield via ring-opening polydisulfide linkage formation from dithiolane pendant groups. These CAN films, which were prepared by a sequential organic synthesis and polymerization process, exhibited high thermal stability and good mechanical properties, recyclability, and self-healing performance. When lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt was added to the CAN films, the films exhibited a maximum ion conductivity of 7.48 × 10-4 S cm-1 because of the contribution of the high concentration of the pendant ethylene carbonate group in the CANs. The ion-conducting CAN films also showed excellent recyclability and a self-healing performance.

15.
RSC Adv ; 13(50): 35050-35064, 2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-38046629

RESUMO

Recently, there has been a significant increase in academic and industrial interest in self-healing polymers (SHPs) due to their remarkable ability to regenerate scratched surfaces and materials of astronomical significance. Scientists have been inspired by the magical repairing mechanism of the living world. They transformed the fiction of self-healing into reality by designing engrossing polymeric materials that could self-repair mechanical abrasions repeatedly. As a result, the durability of the materials is remarkably improved. Thus, the idea of studying SHPs passively upholds economic and environmental sustainability. However, the critical areas of self-healing (including healing efficiency, healing mechanism, and thermo-mechanical property changes during healing) are under continuous scientific improvisation. This review highlights recent notable advances of SHPs for application in regenerating scratched surfaces with various distinctive underlying mechanisms. The primary focus of the work is aimed at discussing the impact of SHPs on scratch-healing technology. Beyond that, insights regarding scratch testing, methods of investigating polymer surfaces, wound depths, the addition of healing fillers, and the environmental conditions maintained during the healing process are reviewed thoroughly. Finally, broader future perspectives on the challenges and prospects of SHPs in healing surface scratches are discussed.

16.
Int J Mol Sci ; 24(24)2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38139223

RESUMO

Age-related macular degeneration (AMD) is a global health challenge. AMD causes visual impairment and blindness, particularly in older individuals. This multifaceted disease progresses through various stages, from asymptomatic dry to advanced wet AMD, driven by various factors including inflammation and oxidative stress. Current treatments are effective mainly for wet AMD; the therapeutic options for dry AMD are limited. Photobiomodulation (PBM) using low-energy light in the red-to-near-infrared range is a promising treatment for retinal diseases. This study investigated the effects of multi-wavelength PBM (680, 780, and 830 nm) on sodium iodate-induced oxidatively damaged retinal tissue. In an in vivo rat model of AMD induced by sodium iodate, multi-wavelength PBM effectively protected the retinal layers, reduced retinal apoptosis, and prevented rod bipolar cell depletion. Furthermore, PBM inhibited photoreceptor degeneration and reduced retinal pigment epithelium toxicity. These results suggest that multi-wavelength PBM may be a useful therapeutic strategy for AMD, mitigating oxidative stress, preserving retinal integrity, and preventing apoptosis.


Assuntos
Terapia com Luz de Baixa Intensidade , Degeneração Macular Exsudativa , Animais , Ratos , Iodatos/toxicidade , Retina
18.
RSC Adv ; 13(51): 36364-36372, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-38099255

RESUMO

Using o-imino isourea, three photo- and thermal dual-responsive radical initiators dicyheDCC, CyheDCC, and BnDCC were systematically developed and synthesized. By adding an aromatic ring to the free radical initiators, the ultraviolet-visible absorption was redshifted, and the absorption coefficient was increased. Compared with other initiators, BnphDCC exhibited an exceptional photoinitiation rate under photo-differential scanning calorimetry (DSC) and a high absorption coefficient (ε = 15 420 M-1 cm-1). Therefore, it is an appropriate potential photoinitiator. DicyheDCC, which was composed of a cyclic hydrocarbon, exhibited rapid thermal initiation (Tpeak = 82 °C) during thermal DSC, making it a valuable thermal radical initiator. Because of the low stiffness of the N-O link in radical initiators, density functional theory predicts that the aliphatic ring has a significantly lower enthalpy than the aromatic ring. Moreover, in this study, CyhephDCC and BnphDCC, as dual-responsive radical initiators, indicated the potential for a photo- and heat dual-curing system through the universal free-radical polymerization of acrylates. These significant discoveries may be useful for developing efficient and diversified polymer network systems that require synergistic photo- and thermal effects.

20.
RSC Adv ; 13(44): 31092-31100, 2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37881755

RESUMO

Control of polymer topologies is essential to determine their unique physical properties and potential applications. The polymer topologies can have a critical effect on pigment dispersion owing to their unique architectures; however, studies using polymer topologies on pigment dispersion in aqueous systems are scarce. Thus, this study proposes various topologies of polyether-based waterborne synergists, such as linear, hyperbranched, and branched cyclic structures. Specifically, we applied branched types of polyglycidols (PGs) as a synergist to provide polymer topology-dependent dispersibility for the surface-modification of Red 170 particles through adsorption and steric hindrance. The topology-controlled PG synergists (PGSs) were successfully prepared by post-polymerization modification with phthalimide and benzoyl groups. Particularly, the branched types of PGSs, branched cyclic PGS (bc-PGS), and hyperbranched PGS (hb-PGS) exhibited improved dispersibility through adsorption on top of the pigment, interaction between dispersant (BYK 190) and pigment, and steric effect. Surprisingly, hb-PGS conferred the Red 170 pigment particles with superior storage stability than that of bc-PGS despite their similar structural features. This study suggests the widespread potential application of PGSs as waterborne synergists for various dispersion applications.

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