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1.
Molecules ; 26(3)2021 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-33498606

RESUMO

The filament is the most widespread feedstock material form used for fused deposition modeling printers. Filaments must be manufactured with tight dimensional tolerances, both to be processable in the hot-end and to obtain printed objects of high quality. The ability to successfully feed the filament into the printer is also related to the mechanical properties of the filament, which are often insufficient for pharmaceutically relevant excipients. In the scope of this work, an 8 mm single screw hot-end was designed and characterized, which allows direct printing of materials from their powder form and does not require an intermediate filament. The capability of the hot-end to increase the range of applicable excipients to fused deposition modeling was demonstrated by processing and printing several excipients that are not suitable for fused deposition modeling in their filament forms, such as ethylene vinyl acetate and poly(1-vinylpyrrolidone-co-vinyl acetate). The conveying characteristic of the screw was investigated experimentally with all materials and was in agreement with an established model from literature. The complete design information, such as the screw geometry and the hot-end dimensions, is provided in this work.


Assuntos
Composição de Medicamentos/métodos , Excipientes/química , Polímeros/química , Pós/química , Solubilidade , Compostos de Vinila/química
2.
Carbohydr Polym ; 256: 117525, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33483046

RESUMO

Microfibrillated cellulose (MFC) is widely used as a reinforcement filler for biocomposites due to its unique properties. However, the challenge of drying MFC and the incompatibility between nanocellulose and polymer matrix still limits the mechanical performance of MFC-reinforced biocomposites. In this study, we used a water-based transesterification reaction to functionalize MFC and explored the capability of oven-dried MFC as a reinforcement filler for polylactic acid (PLA). Remarkably, this oven-dried, vinyl laurate-modified MFC improved the tensile strength by 38 % and Young's modulus by 71 % compared with neat PLA. Our results suggested improved compatibility and dispersion of the fibrils in PLA after modification. This study demonstrated that scalable water-based surface modification and subsequent straightforward oven drying could be a facile method for effectively drying cellulose nanomaterials. The method helps significantly disperse fibrils in polymers and enhances the mechanical properties of microfibrillar cellulose-reinforced biocomposites.


Assuntos
Celulose/química , Lauratos/química , Nanocompostos/química , Poliésteres/química , Compostos de Vinila/química , Varredura Diferencial de Calorimetria , Celulose/ultraestrutura , Dessecação/métodos , Módulo de Elasticidade , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanocompostos/ultraestrutura , Propriedades de Superfície , Resistência à Tração , Termogravimetria , Água/química
3.
ACS Appl Mater Interfaces ; 13(3): 3631-3644, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33448783

RESUMO

Three-dimensional (3D) scaffolds with optimum physicochemical properties are able to elicit specific cellular behaviors and guide tissue formation. However, cell-material interactions are limited in scaffolds fabricated by melt extrusion additive manufacturing (ME-AM) of synthetic polymers, and plasma treatment can be used to render the surface of the scaffolds more cell adhesive. In this study, a hybrid AM technology, which combines a ME-AM technique with an atmospheric pressure plasma jet, was employed to fabricate and plasma treat scaffolds in a single process. The organosilane monomer (3-aminopropyl)trimethoxysilane (APTMS) and a mixture of maleic anhydride and vinyltrimethoxysilane (MA-VTMOS) were used for the first time to plasma treat 3D scaffolds. APTMS treatment deposited plasma-polymerized films containing positively charged amine functional groups, while MA-VTMOS introduced negatively charged carboxyl groups on the 3D scaffolds' surface. Argon plasma activation was used as a control. All plasma treatments increased the surface wettability and protein adsorption to the surface of the scaffolds and improved cell distribution and proliferation. Notably, APTMS-treated scaffolds also allowed cell attachment by electrostatic interactions in the absence of serum. Interestingly, cell attachment and proliferation were not significantly affected by plasma treatment-induced aging. Also, while no significant differences were observed between plasma treatments in terms of gene expression, human mesenchymal stromal cells (hMSCs) could undergo osteogenic differentiation on aged scaffolds. This is probably because osteogenic differentiation is rather dependent on initial cell confluency and surface chemistry might play a secondary role.


Assuntos
Células-Tronco Mesenquimais/citologia , Gases em Plasma/química , Engenharia Tecidual/métodos , Tecidos Suporte/química , Adesão Celular , Linhagem Celular , Proliferação de Células , Humanos , Osteogênese , Silanos/química , Compostos de Vinila/química , Molhabilidade
4.
Carbohydr Polym ; 253: 117205, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33278975

RESUMO

In this work, a novel chitosan based structure (CS/EVC) with low density, high porosity, three-dimensional porous structure and great adsorption capability has been prepared by using 1,2-epoxy-4-vinyl cyclohexane (EVC) as a cross-linker. After immersing CS/EVC in N-halamine 1-chloro-2,2,5,5-tetramethyl-4-imidazolinone (MC) solution, antibacterial CS/EVC/MC compounds were obtained. Compared with chitosan and CS/EVC controls, CS/EVC/MC showed excellent antimicrobial activities, which could inactivate both more than 6 logs (×1/1,000,000) of Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 8099) within 30 and 10 min, respectively. Moreover, the relatively low blood clotting index of CS/EVC/MC and the activation of platelets adhering to the surfaces indicated that the CS/EVC/MC sample is potential to promote the agglutination abilities of blood cells and simultaneously control wound bleeding. In addition, in vitro cytotoxicity test showed that the CS/EVC/MC had no cytotoxicity. The material might thus have a great potential for biomedical applications.


Assuntos
Aminas/química , Antibacterianos/química , Coagulação Sanguínea/efeitos dos fármacos , Quitosana/química , Escherichia coli/efeitos dos fármacos , Hemostáticos/química , Staphylococcus aureus/efeitos dos fármacos , Células 3T3 , Adsorção , Animais , Antibacterianos/farmacologia , Reagentes para Ligações Cruzadas/química , Compostos de Epóxi/química , Hemorragia/tratamento farmacológico , Hemostáticos/farmacologia , Camundongos , Testes de Sensibilidade Microbiana , Porosidade , Coelhos , Compostos de Vinila/química , Cicatrização/efeitos dos fármacos
5.
Carbohydr Polym ; 254: 117399, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357889

RESUMO

Starch based materials are attractive bio-based alternative to fully synthetic polymers. Native starch has however limited thermoprocessability and properties and must be modified. In order to improve the properties of starch-graft-poly(butyl-acrylate-co-styrene) copolymers via a process as green as possible, we report herein a new method for the dual functionalization of the polysaccharide via a one pot one step reaction in aqueous medium combining free radical polymerizations and ring-opening chemistry. Poly(butyl acrylate) or poly(butyl acrylate-co-styrene) (ca. 60 000 g/mol) and oligo(ε-caprolactone) were grafted on starch with a grafting percentage up to 75 %. The copolymers show two glass transition temperatures: one around 55-60 °C related to starch and a second attributed to the grafted vinyl polymers, from -46 °C to 20 °C depending on butyl acrylate/styrene ratio. The resulting dual functionalized materials exhibit excellent mechanical properties, with elongation at break in the range 20-210 %, while single functionalized starch shows less than 5 %.


Assuntos
Polimerização , Amido/química , Água/química , Acrilatos/química , Resinas Acrílicas/química , Caproatos/química , Radicais Livres/química , Lactonas/química , Poliestirenos/química , Temperatura de Transição , Compostos de Vinila/química
6.
J Oleo Sci ; 69(11): 1437-1443, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33055440

RESUMO

We report the synthesis of bolaamphiphilic alkenyl phosphonic acid (BPC12) through the olefin crossmetathesis reaction of vinylphosphonic acid with 1,11-dodecadiene in the presence of a Ru-carbene catalyst. BPC12 possesses two trans-P-C=C moieties and is thus readily soluble in water up to 3.4 g L-1, as confirmed by 1H nuclear magnetic resonance (NMR) measurements. Surface tension measurements revealed that BPC12 reduced the surface tension of water from 72.0 to 47.0 mN m‒1. The occupied area per molecule at the air/water interface (A) of BPC12 (216 Å2) was ten times larger than that of dodecenyl phosphonic acid PC12 (23 Å2). Moreover, dynamic light scattering measurement of an aqueous BPC12 solution (5 mM) revealed the formation of large aggregates with an average diameter of 81.8±27.0 nm.


Assuntos
Alcenos/química , Metano/análogos & derivados , Organofosfonatos/química , Ácidos Fosforosos/síntese química , Compostos de Vinila/química , Ar , Catálise , Difusão Dinâmica da Luz , Espectroscopia de Ressonância Magnética , Metano/química , Fenômenos de Química Orgânica , Tamanho da Partícula , Ácidos Fosforosos/química , Solubilidade , Tensão Superficial , Água
7.
J Chromatogr A ; 1632: 461541, 2020 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-33059176

RESUMO

This work presents the development and validation of novel thin film solid phase micro extraction (TF-SPME) based standard gas generating vials suitable for repeatable generation of gaseous standards for GC-MS analysis and quality control. The vials were developed using carbon mesh membranes loaded with pure polydimethylsiloxane (PDMS), divinylbenzene (DVB/PDMS), hydrophilic-lipophilic balance (HLB/PDMS), and carboxen (Car/PDMS) sorbents that were then spiked with modified McReynolds standards including benzene, 2-pentanone, 1-nitropropane, pyridine, 1-pentanol, octane, dodecane, and hexadecane. Sorbent strength was determined to follow the aforementioned order, with pure PDMS presenting the weakest sorption capabilities and Car/PDMS the strongest. While the weaker, pure PDMS based gas generating vials transferred an instrument-overloading amount of McReynolds probes to the 1.1 mm DVB/PDMS SPME arrows used for extraction, vials prepared using Car/PDMS TF-SPME as a sorbent failed to provide consistently detectable amounts of analytes less volatile than 1-nitropropane. The DVB/PDMS and HLB/PDMS based vials were found to maintain optimal sorption capabilities for the tested analytes, providing a sorption strength strong enough to not exhibit any depletion in 10 replicate runs, while still delivering a consistent amount of all the regular McReynolds components. Moreover, with intra-vial%RSDs of 5% or less for all analytes tested, these HLB and DVB vials were found to deliver very good repeatability. After purposely submitting vials to 200 accelerated depletion extractions (1.1 mm DVB/PDMS arrow at 55 °C for 3 min), vials prepared with DVB/PDMS were found to deplete by 33%, 38%, 34%, 33%, 40%, and 33% while vials prepared with HLB/PDMS were found to deplete by 21%, 16%, 12%, 31%, 16% and 0% for benzene, 2-pentanone, 1-nitropropane, pyridine, 1-pentanol, and octane, respectively. When user typical extractions conditions were used instead (50/30 µm DVB/Car/PDMS SPME fiber at 35 °C for 1 min), no depletion could be observed from the HLB/PDMS based vial while%RSDs ranged from 1.1-3.0% after the 300 extraction/desorption cycles. Finally, in efforts to demonstrate its real world applicability, the DVB/PDMS vial was used to evaluate the inter-fiber repeatability of commercial DVB/PDMS SPME arrows, with results demonstrating that arrows from a single package were statistically similar (ANOVA at 95% confidence).


Assuntos
Gases/análise , Microextração em Fase Sólida/métodos , Análise de Variância , Dimetilpolisiloxanos/química , Cromatografia Gasosa-Espectrometria de Massas , Membranas Artificiais , Controle de Qualidade , Padrões de Referência , Reprodutibilidade dos Testes , Compostos de Vinila/química
8.
J Chromatogr A ; 1626: 461363, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797842

RESUMO

Analytical techniques to determine volatile compounds such as flavor, aroma, and fragrances are in high demand due to their wide range of applications in industry, the chemical properties of them are very diverse. Supercritical fluid chromatography (SFC) is capable of high speed, high peak capacity separation and has a high separation coverage. It is also an advantageous for preparative purifications due to its unique mobile phase conditions. However, there is no column commercially available for SFC that is suitable to comprehensively separate volatile compounds. SFC is limited to the use of silica-based columns due to weak retentions and polymer-based column issues such as pressure, swelling and shrinkage tolerances. This study demonstrated comprehensive analytical method for volatile in SFC using a highly cross-linked styrene divinylbenzene (SDVB) polymer-based column, newly developed for SFC. In this study, 23 typical volatile compounds with a wide variety of chemical properties were selected as model compounds. The newly developed SDVB column showed, compared to conventional silica-based columns (k > 0.3), an excellent overall and substantial improved retentions (k > 1.6) under SFC mobile phase conditions. It was also able to retain esters (hydroxy acetate, pentyl butylate, methyl salicylate) and non-polar terpenes (limonene, pinene) that did not show sufficient retention in any other commercially available silica-based columns. Aldehydes reacting on NH2 column due to Schiff base formation were also successfully eluted. It was confirmed that SDVB column provided comprehensive separation and wide coverage for volatile compounds.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Poliestirenos/química , Compostos de Vinila/química , Espectrometria de Massas , Dióxido de Silício , Terpenos/isolamento & purificação , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/isolamento & purificação
9.
J Chromatogr A ; 1623: 461154, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505273

RESUMO

Chiral stationary phases (CSPs) have always been research hotspot in enantiomer separation. Currently, most of the CSPs are based on silica platform. In this research, monodisperse, porous glycidyl methacrylate-divinylbenzene copolymer particles (poly(GMA-DVB)) were designed and prepared. Then the GMA was further reacted with ethylenediamine to introduce amino groups onto the polymer, which provide anchoring sites for cellulose derivatives. Herein, Cellulose-tris (3,5-dimethylphenylcarbamate) (CDMPC) was successfully coated onto the polymer microspheres, achieving a stable and successful CSP. The porous structure and the surface moieties of the CSPs were studied in detail. The chromatographic separation was optimized. Hexaconazole,methyl DL-mandelate,benzoin and tebuconazole have been successfully separated on the CSP column, with column efficiency as high as 10,200 plates/m, which is comparable with some silica-based CSPs. The research has indicated that the poly(GMA-DVB) is a promising candidate for constructing CSPs for chiral separation.


Assuntos
Celulose/análogos & derivados , Microesferas , Fenilcarbamatos/química , Polímeros/química , Celulose/química , Cromatografia Líquida de Alta Pressão/métodos , Compostos de Epóxi/química , Metacrilatos/química , Porosidade , Dióxido de Silício/química , Estereoisomerismo , Triazóis/química , Compostos de Vinila/química
10.
J Chromatogr A ; 1623: 461159, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505275

RESUMO

In the last decade, 3D-printing has emerged as a promising enabling technology in the field of analytical chemistry. Fused-deposition modelling (FDM) is a popular, low-cost and widely accessible technique. In this study, RPLC separations are achieved by in-situ fabrication of porous polymer monoliths, directly within the 3D-printed channels. Thermal polymerization was employed for the fabrication of monolithic columns in optically non-transparent column housings, 3D-printed using two different polypropylene materials. Both acrylate-based and polystyrene-based monoliths were created. Two approaches were used for monolith fabrication, viz. (i) in standard polypropylene (PP) a two-step process was developed, with a radical initiated wall-modification step 2,2'-azobis(2-methylpropionitrile) (AIBN) as the initiator, followed by a polymerization step to generate the monolith; (ii) for glass-reinforced PP (GPP) a silanization step or wall modification preceded the polymerization reaction. The success of wall attachment and the morphology of the monoliths were studied using scanning electron microscopy (SEM), and the permeability of the columns was studied in flow experiments. In both types of housings polystyrene-divinylbenzene (PS-DVB) monoliths were successfully fabricated with good wall attachment. Within the glass-reinforced polypropylene (GPP) printed housing, SEM pictures showed a radially homogenous monolithic structure. The feasibility of performing liquid-chromatographic separations in 3D-printed channels was demonstrated.


Assuntos
Cromatografia de Fase Reversa/métodos , Polipropilenos/química , Impressão Tridimensional , Microscopia Eletrônica de Varredura , Polimerização , Polímeros/química , Poliestirenos/química , Porosidade , Compostos de Vinila/química
11.
J Chromatogr A ; 1623: 461175, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505279

RESUMO

An ionic liquid hybrid zwitterionic polymer capillary microextraction (CME) column was prepared for the biomimetic enrichment of glycopeptides by one-step copolymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 1-butyl-3-vinylimidazolium bromide, in the presence of crosslinker trimethylolpropane trimethacrylate (TMA). The resultant monolith was characterized by scanning electron microscopy (SEM), fourier transform infrared (FT-IR) spectroscopy and pore size distribution measurement. Due to the incorporation of zwitterionic MPC owning a unique biomimic structure (i.e. hydrophilic cation/anion and hydrophobic long-alkyl chain), the monolithic column has large pore size and good biocompatibility, exhibiting high extraction efficiency, permeability and fast mass transfer to targets. Besides, the use of ionic liquids (ILs) as co-monomer in the polymerization endows the monolith with enhanced mechanical stability, uniformity and multiple interactions. The prepared column was successfully applied in CME coupled to capillary electrochromatography (CEC) for the efficient enrichment and separation of glycopeptide antibiotics in foodstuff. The method demonstrated a wide linear range (50.0-18000.0 µg L-1), low detection limits (5.0-10.0 µg L-1, S/N = 3) and satisfied recoveries (76.0-109.7%). This work shows the advantage of fine-tuning biomimetic monoliths in application-specific CME-CEC.


Assuntos
Antibacterianos/análise , Eletrocromatografia Capilar/métodos , Glicopeptídeos/análise , Líquidos Iônicos/química , Antibacterianos/isolamento & purificação , Materiais Biomiméticos , Fracionamento Químico , Análise de Alimentos/métodos , Glicopeptídeos/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Imidazóis/química , Metacrilatos/química , Microscopia Eletrônica de Varredura , Fosforilcolina/análogos & derivados , Fosforilcolina/química , Polimerização , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Compostos de Vinila/química
12.
Pharm Res ; 37(6): 94, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32405662

RESUMO

PURPOSE: An investigation of underlying mechanisms of API-polymer interaction patterns has the potential to provide valuable insights for selecting appropriate formulations with superior physical stability and processability. MATERIALS AND METHODS: In this study, copovidone was used as a polymeric carrier for several model compounds including clotrimazole, nifedipine, and posaconazole. The varied chemical structures conferred the ability for the model compounds to form distinct interactions with copovidone. Rheology and nuclear magnetic resonance (NMR) were combined to investigate the molecular pattern and relative strength of active pharmaceutical ingredient (API)-polymer interactions. In addition, the impact of the interactions on formulation processability via hot melt extrusion (HME) and physical stability were evaluated. RESULTS: The rheological response of an API-polymer system was found to be highly sensitive to API-polymer interaction, depending both on API chemistry and API-polymer miscibility. In the systems studied, dispersed API induced a stronger plasticizer effect on the polymer matrix compared to crystalline/aggregated API. Correspondingly, the processing torque via HME showed a proportional relationship with the maximum complex viscosity of the API-polymer system. In order to quantitatively evaluate the relative strength of the API-polymer interaction, homogeneously dispersed API-polymer amorphous samples were prepared by HME at an elevated temperature. DSC, XRD, and rheology were employed to confirm the amorphous integrity and homogeneity of the resultant extrudates. Subsequently, the homogeneously dispersed API-polymer amorphous dispersions were interrogated by rheology and NMR to provide a qualitative and quantitative assessment of the nature of the API-polymer interaction, both macroscopically and microscopically. Rheological master curves of frequency sweeps of the extrudates exhibited a strong dependence on the API chemistry and revealed a rank ordering of the relative strength of API-copovidone interactions, in the order of posaconazole > nifedipine > clotrimazole. NMR data provided the means to precisely map the API-polymer interaction pattern and identify the specific sites of interaction from a molecular perspective. Finally, the impact of API-polymer interactions on the physical stability of the resultant extrudates was studied. CONCLUSION: Qualitative and quantitative evaluation of the relative strength of the API-polymer interaction was successfully accomplished by utilizing combined rheology and NMR. Graphical Abstract.


Assuntos
Clotrimazol/química , Portadores de Fármacos/química , Nifedipino/química , Pirrolidinas/química , Triazóis/química , Compostos de Vinila/química , Composição de Medicamentos , Liberação Controlada de Fármacos , Elasticidade , Tecnologia de Extrusão por Fusão a Quente , Temperatura Alta , Espectroscopia de Ressonância Magnética , Conformação Molecular , Reologia , Relação Estrutura-Atividade , Viscosidade
13.
Pharm Res ; 37(4): 70, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32185516

RESUMO

PURPOSE: While including amorphous solid dispersion (ASD) in tablet formulations is increasingly common, tablets containing high ASD loading are associated with slow disintegration, which presents a challenge to control pill burden for less potent compounds. METHODS: We use a model ASD, composed of a hydrophobic drug with copovidone and a non-ionic surfactant, to explore formulation options that can prevent slow disintegration. RESULTS: In addition to the ASD loading, the pH of the disintegration medium and the inclusion of inorganic salts in the tablet also have an impact on the tablet disintegration time. Certain kosmotropic salts, when added in the formulation, can significantly accelerate tablet disintegration, though the rank order in their effectiveness does not exactly follow the Hofmeister series at pH 1.8. The particle size and dissolution rate of the salt can contribute to its overall effectiveness. CONCLUSION: We provided a mechanistic explanation of the disintegration process: fast-dissolving kosmotropic salt results in a concentrated salt solution inside the restrained tablet matrix, thus inhibiting the dissolution of copovidone and preventing polymer gelling which is the main cause leading the slow disintegration. The outcome of this study has enabled the design of a higher ASD loading platform formulation for copovidone based ASD. Graphical Abstract MicroCT aids the mechanistic understanding of the role of inorganic salt in the tablet disintegration of amorphous solid dispersion based formulation.


Assuntos
Pirrolidinas/química , Sais/química , Comprimidos/química , Compostos de Vinila/química , Química Farmacêutica , Excipientes/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Concentração Osmolar , Tamanho da Partícula , Solubilidade
14.
Colloids Surf B Biointerfaces ; 188: 110807, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31972445

RESUMO

Porous cross-linked poly (glycidyl methacrylate-divinylbenzene) (PGMA-DVB) particles (7.42 ± 0.24 µm in diameter) were prepared by an improved two-step seed swelling polymerization method. The PGMA-DVB particles were further modified with poly (allylamine hydrochloride) (PAH) and 4-(bromomethyl) phenylboronic acid (BPA), which were used as high performance liquid chromatography (HPLC) filler for nucleotides separation. The liquid chromatographic column packing materials successfully achieved complete separation of nucleotides mixture or deoxynucleotides mixture based on non-polar adsorption, hydrogen bonding interaction and electrostatic adsorption. Reckoning on the chemical structure of BPA, nucleotides and deoxynucleotides with same base group were also separated. The column packing materials were durable after over 100 time running or 7 days. It presents a kind of new notion for the separation of nucleotides by HPLC.


Assuntos
Ácidos Borônicos/química , Compostos de Epóxi/química , Metacrilatos/química , Microesferas , Polímeros/síntese química , Compostos de Vinila/química , Cromatografia Líquida de Alta Pressão , Estrutura Molecular , Tamanho da Partícula , Polimerização , Polímeros/química , Propriedades de Superfície
15.
Nat Commun ; 11(1): 446, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31974383

RESUMO

Afterglow luminescent probes with high signal-to-background ratio show promise for in vivo imaging; however, such probes that can be selectively delivered into target sites and switch on afterglow luminescence remain limited. We optimize an organic electrochromic material and integrate it into near-infrared (NIR) photosensitizer (silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) and (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) containing nanoparticles, developing an H2S-activatable NIR afterglow probe (F12+-ANP). F12+-ANP displays a fast reaction rate (1563 ± 141 M-1 s-1) and large afterglow turn-on ratio (~122-fold) toward H2S, enabling high-sensitivity and -specificity measurement of H2S concentration in bloods from healthy persons, hepatic or colorectal cancer patients. We further construct a hepatic-tumor-targeting and H2S-activatable afterglow probe (F12+-ANP-Gal) for noninvasive, real-time imaging of tiny subcutaneous HepG2 tumors (<3 mm in diameter) and orthotopic liver tumors in mice. Strikingly, F12+-ANP-Gal accurately delineates tumor margins in excised hepatic cancer specimens, which may facilitate intraoperative guidance of hepatic cancer surgery.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Sulfeto de Hidrogênio/análise , Neoplasias Hepáticas/diagnóstico por imagem , Substâncias Luminescentes/química , Imagem Molecular/métodos , Animais , Neoplasias Colorretais/sangue , Cistationina beta-Sintase/análise , Cistationina beta-Sintase/metabolismo , Cistationina gama-Liase/análise , Cistationina gama-Liase/metabolismo , Células Hep G2 , Humanos , Sulfeto de Hidrogênio/sangue , Sulfeto de Hidrogênio/química , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas Experimentais/diagnóstico por imagem , Substâncias Luminescentes/síntese química , Camundongos Endogâmicos BALB C , Nanopartículas/química , Fármacos Fotossensibilizantes/química , Polímeros/química , Compostos de Vinila/química , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Molecules ; 25(2)2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31952168

RESUMO

Lipase B from Candida antarctica immobilized by covalent binding on sebacoyl-activated chitosan-coated magnetic nanoparticles proved to be an efficient biocatalyst (49.2-50% conversion in 3-16 h and >96% enantiomeric excess) for the enzymatic kinetic resolution of some racemic heteroarylethanols through transesterification with vinyl acetate. Under optimal conditions (vinyl acetate, n-hexane, 45 °C), the biocatalyst remains active after 10 cycles.


Assuntos
Candida/enzimologia , Quitosana/química , Enzimas Imobilizadas/metabolismo , Proteínas Fúngicas/metabolismo , Lipase/metabolismo , Nanopartículas de Magnetita/química , Compostos de Vinila/química , Catálise , Enzimas Imobilizadas/química , Esterificação , Proteínas Fúngicas/química , Cinética , Lipase/química , Estereoisomerismo
17.
Int J Pharm ; 577: 119065, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31988034

RESUMO

In the pharmaceutical industry, polymers are used as excipients for formulating poorly water-soluble active pharmaceutical ingredients (APIs) in so-called "amorphous solid dispersions" (ASDs). ASDs can be produced via solvent-based processes, where API and polymer are both dissolved in a solvent, followed by a solvent evaporation step (e.g. spray drying). Aiming at a homogeneous API/polymer formulation, phase separation of the components (API, polymer, solvent) during solvent evaporation must be avoided. The latter is often determined by the phase behavior of polymer/solvent mixtures used for ASD processing. Therefore, this work investigates the polymer-solvent interactions in these mixtures. Suitable polymer/solvent combinations investigated in this work comprise the pharmaceutically relevant polymers poly(vinylpyrrolidone) (PVP), poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA64), and hydroxyppropyl methylcellulose acetate succinate 126G (HPMCAS) as well as the solvents acetone, dichloromethane (DCM), ethanol, ethyl acetate, methanol, and water. Based on vapor-sorption experiments demixing of solvents and polymers were predicted using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT). These were found to be correct for all investigated solvent/polymer mixtures. Acetone, DCM, ethanol, methanol, and water were found to be completely miscible with PVPVA64. DCM, ethanol, methanol, and water were found to be completely miscible with PVP K90, while none of the investigated solvents was appropriate for avoiding immiscibility with HPMCAS. In addition, the impact of temperature, polymer molecular weight, and solvent-mixture composition on miscibility was successfully predicted using PC-SAFT. Thus, the proposed methodology allows identifying suitable solvents or solvent mixtures relevant for solvent-based preparations of pharmaceutical ASD formulations with low experimental effort.


Assuntos
Química Farmacêutica , Excipientes/química , Polímeros/química , Solventes/química , Metilcelulose/análogos & derivados , Metilcelulose/química , Peso Molecular , Transição de Fase , Povidona/química , Pirrolidinas/química , Temperatura , Compostos de Vinila/química
18.
Macromol Rapid Commun ; 41(4): e1900550, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31894629

RESUMO

Thermo-responsive block copolymers are of great interest in biomedical and nanotechnological fields. These polymers achieve a versatile and complex responsiveness through a sophisticated and intricate combination of different thermo-responsive blocks. While their utility is clear, the fundamental design principles of such vinyl polymers are not yet thoroughly understood. Herein, a precise synthesis of sequence-controlled amino-acid-derived vinyl polymers and their unique thermal response in water are reported. Seven distinct block (random) copolymers that contain two kinds of amino acid blocks (poly(N-acryloyl alanine(A)- or glycine(G)-methyl ester)) with the same total chain length (degree of polymerization [DP] ≈30) and chemical composition (A/G ≈1), but with systematic variations in the block sequence and length, with an accuracy target of DP ± 1, are prepared. By specifying the primary structure, the thermal responses including transition temperature, thermo-sensitivity, and microenvironment in the dehydrated state can be finely tuned. These findings offer new directions in the design of structurally and functionally diverse thermo-responsive vinyl polymers.


Assuntos
Polímeros/química , Polímeros/síntese química , Compostos de Vinila/química , Alanina/análogos & derivados , Alanina/química , Aminoácidos/química , Glicina/análogos & derivados , Glicina/química , Polimerização , Temperatura , Água
19.
Org Biomol Chem ; 18(2): 255-262, 2020 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-31815989

RESUMO

Five 2-substituted 2'-deoxyinosine triphosphates (dRITP) were synthesized and tested as substrates in enzymatic synthesis of minor-groove base-modified DNA. Only 2-methyl and 2-vinyl derivatives proved to be good substrates for Therminator DNA polymerase, whilst all other dRITPs and other tested DNA polymerases did not give full length products in primer extension. The DNA containing 2-vinylhypoxanthine was then further modified through thiol-ene reactions with thiols. Cross-linking reaction between cysteine-containing minor-groove binding dodecapeptide and DNA proceeded thanks to the proximity effect between thiol and vinyl groups inside the minor groove. 2-Substituted dIRTPs and also previously prepared 2-substituted 2'-deoxyadenosine triphosphates (dRATP) were then used for enzymatic synthesis of minor-groove modified DNA to study the effect of minor-groove modifications on cleavage of DNA by type II restriction endonucleases (REs). Although the REs should recognize the sequence through H-bonds in the major groove, some minor-groove modifications also had an inhibiting effect on the cleavage.


Assuntos
Enzimas de Restrição do DNA/metabolismo , DNA Polimerase Dirigida por DNA/metabolismo , DNA/química , Inosina Trifosfato/análogos & derivados , Especificidade por Substrato , DNA/biossíntese , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Ligação de Hidrogênio , Inosina Trifosfato/síntese química , Inosina Trifosfato/metabolismo , Conformação de Ácido Nucleico , Relação Estrutura-Atividade , Compostos de Vinila/química
20.
J Chromatogr A ; 1615: 460776, 2020 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-31839354

RESUMO

Inspired by the fact that antibody recognizes antigen's epitope rather than its whole structure, we selected the glycosyl moiety of teicoplanin as the template, 4-vinylphenylboronic acid and methyl methacrylate as the functional monomers, and divinylbenzene as the cross-linker to synthesis molecularly imprinted polymer microspheres via precipitation co-polymerization. The glycosyl-imprinted microspheres can selectively capture the target glycopeptide antibiotic in aqueous solutions when the pH of surrounding environment is 9.0, and the captured antibiotic can be reversibly released when the pH falls below 4.0 again. This pH-controlled catch-and-release mechanism permits entrapping of glycopeptide antibiotics in slightly basic environments and keeping them entrapped under neutral conditions, and eluting in acidic media. Five teicoplanin components were selectively captured by using the prepared glycosyl-imprinted microspheres as solid-phase extraction adsorbents, and then detected using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). Finally, the method was thoroughly validated for accuracy and reproducibility by determining teicoplanin in food and biological samples, and achieving quantification limits of 0.1 µg/kg, 0.5 µg/L and 1.0 µg/L for milk, urine and plasma samples, respectively.


Assuntos
Cromatografia Líquida de Alta Pressão , Análise de Alimentos/métodos , Microesferas , Polímeros/química , Extração em Fase Sólida/instrumentação , Espectrometria de Massas em Tandem , Teicoplanina/análise , Animais , Antibacterianos/análise , Antibacterianos/isolamento & purificação , Limite de Detecção , Leite/química , Impressão Molecular , Polimerização , Reprodutibilidade dos Testes , Compostos de Vinila/química , Água/química
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