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1.
J Pharm Biomed Anal ; 177: 112852, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31499432

RESUMO

The effect of insertion of SH and S-protected groups on the binding and mucoadhesion properties of quaternary ammonium-chitosans and their nanoparticulate forms has been investigated by NMR spectroscopy. Diclofenac sodium salt has been assumed as low molecular weight probe to detect the different binding behaviour of polymeric materials; mucin from bovine submaxillary glands was selected as the model protein for differentiating their mucoadhesion. NMR proton selective relaxation rates of the probe molecule were remarkably sensitive to the presence of very low amounts of sulfurated moieties. Impact of supramolecular aggregation in nanostructured species was demonstrated as well as the relevance of S-protection.


Assuntos
Diclofenaco/administração & dosagem , Portadores de Fármacos/química , Membrana Mucosa/metabolismo , Nanopartículas/química , Adesividade , Animais , Bovinos , Quitosana/química , Quitosana/metabolismo , Portadores de Fármacos/metabolismo , Peso Molecular , Mucinas/metabolismo , Nanopartículas/metabolismo , Espectroscopia de Prótons por Ressonância Magnética , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/metabolismo , Enxofre/química
2.
Braz Oral Res ; 33: e111, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31800863

RESUMO

The aim of the present study was to evaluate the microtensile bond strength and the microleakage of a bulk-fill composite resin compared with a conventional incremental composite resin, in permanent molars and under cariogenic challenge using a Streptococcus mutans model. Permanent human third molars (n = 60) with an occlusal cavity of 5×3×2 mm were randomly allocated into four subgroups of restorative treatments: conventional composite resin with (n = 15) and without (n = 15) cariogenic challenge (Z350-E and Z350-C experimental and control groups, respectively), and bulk-fill composite resin with (n = 15) and without (n = 15) cariogenic challenge (Bulk Fill-E and Bulk Fill-C, respectively). Ten specimens from each subgroup were submitted to microtensile strength, and 5, to microleakage. The cariogenic challenge was conducted using the Streptococcus mutans strain (ATCC) for 7 days. The stickers obtained (1 × 1 × 2 mm) were submitted to a microtensile strength test, followed by classification of the fracture mode. Microleakage was performed using a scoring system. The data were analyzed by Kruskal-Wallis and Mann-Whitney tests (p < 0.05). Filtek Z350 XT resin presented higher microtensile bond strength than Bulk Fill resin without (19.02 ± 4.90 and 8.76 ± 3.94MPa, respectively; p < 0.001) and with cariogenic challenge (22.69 ± 7.86 and 13.31 ± 3.38MPa, respectively; p < 0.02). Z350-C and Bulk Fill-C resins presented a higher prevalence of mixed fractures (23 and 14%, respectively) in the specimens submitted to cariogenic challenge than those of the control groups, whereas microleakage was similar (p = 0.85). The conventional composite resin had higher microtensile bond strength than the bulk-fill resin, but both resin types had similar adhesion quality and microfiltration scores.


Assuntos
Biofilmes/efeitos dos fármacos , Resinas Compostas/química , Colagem Dentária/métodos , Streptococcus mutans/efeitos dos fármacos , Adesividade , Cárie Dentária , Esmalte Dentário/efeitos dos fármacos , Infiltração Dentária , Restauração Dentária Permanente/métodos , Humanos , Teste de Materiais , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Propriedades de Superfície , Resistência à Tração/efeitos dos fármacos , Fatores de Tempo
3.
Nature ; 575(7781): 169-174, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31666696

RESUMO

Two dry surfaces can instantly adhere upon contact with each other through intermolecular forces such as hydrogen bonds, electrostatic interactions and van der Waals interactions1,2. However, such instant adhesion is challenging when wet surfaces such as body tissues are involved, because water separates the molecules of the two surfaces, preventing interactions3,4. Although tissue adhesives have potential advantages over suturing or stapling5,6, existing liquid or hydrogel tissue adhesives suffer from several limitations: weak bonding, low biological compatibility, poor mechanical match with tissues, and slow adhesion formation5-13. Here we propose an alternative tissue adhesive in the form of a dry double-sided tape (DST) made from a combination of a biopolymer (gelatin or chitosan) and crosslinked poly(acrylic acid) grafted with N-hydrosuccinimide ester. The adhesion mechanism of this DST relies on the removal of interfacial water from the tissue surface, resulting in fast temporary crosslinking to the surface. Subsequent covalent crosslinking with amine groups on the tissue surface further improves the adhesion stability and strength of the DST. In vitro mouse, in vivo rat and ex vivo porcine models show that the DST can achieve strong adhesion between diverse wet dynamic tissues and engineering solids within five seconds. The DST may be useful as a tissue adhesive and sealant, and in adhering wearable and implantable devices to wet tissues.


Assuntos
Adesividade , Adesivos/química , Coração , Pulmão , Próteses e Implantes , Estômago , Molhabilidade , Resinas Acrílicas/química , Animais , Quitosana/química , Reagentes para Ligações Cruzadas/química , Dessecação , Gelatina/química , Coração/anatomia & histologia , Hidrogéis/química , Ligações de Hidrogênio , Pulmão/anatomia & histologia , Pulmão/química , Camundongos , Ratos , Eletricidade Estática , Estômago/anatomia & histologia , Estômago/química , Suínos , Fatores de Tempo , Água/análise , Água/química , Dispositivos Eletrônicos Vestíveis
4.
Dent Mater ; 35(12): 1750-1756, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31610888

RESUMO

OBJECTIVE: This in vitro study was designed to evaluate the biocompatibility, adhesiveness, and antimicrobial activity of epoxy resin-based sealer associated with N-Acetylcysteine (NAC) or beta-tricalcium phosphate nanoparticles (ß-TCP) as an experimental retro-filling material. METHODS: Cytotoxicity was assessed using 2,3-Bis-(Methoxy-4-Nitro-5-Sulphophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT) and Sulforhodamine B (SRB) assays after exposing human periodontal ligament fibroblasts to extracts of the materials for 1, 3, or 7 days. For the adhesive resistance test, root canals (48 single-root teeth) were instrumented with Reciproc #40 files (VDW GmbH, Germany) and obturated. After 7 days, the apices were sectioned and a retrograde cavity prepared and filled with the experimental materials (Mineral trioxide aggregate, Epoxy sealer, Epoxy sealer+NAC, and Epoxy sealer+ß-TCP). For the push-out test, one 2-mm thick slice was obtained from the apical third of each specimen. Antimicrobial activity was performed using agar diffusion method. Biofilms were grown in microplates and exposed to the extracts of retro-filled materials, followed by analysis of growth inhibition on agar plates. RESULTS: Epoxy sealer in association with ß-TCP or NAC showed better bond strength while Mineral trioxide aggregate allowed for the lowest adhesion. Mineral trioxide aggregate, Epoxy sealer+ß-TCP, and Epoxy sealer+NAC showed low cytotoxicity. Epoxy sealer was the most cytotoxic. In antimicrobial activity assays, all materials had no effect on Candida albicans. Addition of NAC improved the antimicrobial property of Epoxy sealer against Enterococcus faecalis compared to unmodified Epoxy sealer (P<0.05). SIGNIFICANCE: Incorporating ß-TCP or NAC with Epoxy sealer could improve the adhesiveness and biocompatibility for better use in endodontic therapy.


Assuntos
Colagem Dentária , Materiais Restauradores do Canal Radicular , Acetilcisteína , Adesividade , Fosfatos de Cálcio , Cavidade Pulpar , Dentina , Resinas Epóxi , Humanos , Teste de Materiais
5.
Int J Nanomedicine ; 14: 7191-7213, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31564873

RESUMO

Background: Diosmin showed poor water solubility and low bioavailability. Poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles were successfully used to improve the drugs solubility and bioavailability. Coating of PLGA nanoparticles with chitosan can ameliorate their gastric retention and cellular uptake. Methodology: PLGA nanoparticles of diosmin were prepared using different drug and polymer amounts. Nanoparticles were selected based on entrapment efficiency% (EE%) and particle size measurements to be coated with chitosan. The selected nanoparticles either uncoated or coated were evaluated regarding morphology, ζ-potential, solid-state characterization, in vitro release, storage stability, and mucoadhesion. The anti-ulcer activity (AA) against ethanol-induced ulcer in rats was assessed through macroscopical evaluation, histopathological examination, immunohistochemical localization of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and transmission electron microscopic examination of gastric tissues compared to free diosmin (100 mg/kg) and positive control. Results: Based on EE% and particle size measurements, the selected nanoparticles, either uncoated or coated with 0.1% w/v chitosan, were based on 1:15 drug-PLGA weight ratio and 20 mg diosmin employing methylene chloride as an organic phase. Examination by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed nanoscopic spherical particles. Drug encapsulation within the selected nanoparticles was suggested by Fourier transform-infrared, differential scanning calorimetry (DSC) and X-ray diffractometry results. Chitosan-coated nanoparticles were more stable against size enlargement probably due to the higher ζ-potential. Only coated nanoparticles showed gastric retention as revealed by SEM examination of stomach and duodenum. The superior AA of coated nanoparticles was confirmed by significant reduction in average mucosal damage, the majority of histopathological changes and NF-κB expression in gastric tissue when compared to positive control, diosmin and uncoated nanoparticles as well as insignificant difference relative to normal control. Coated nanoparticles preserved the normal ultrastructure of the gastric mucosa as revealed by TEM examination. Conclusion: The optimized chitosan-coated PLGA nanoparticles can be represented as a potential oral drug delivery system of diosmin.


Assuntos
Antiulcerosos/uso terapêutico , Quitosana/química , Diosmina/uso terapêutico , Nanopartículas/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Estômago/patologia , Úlcera/tratamento farmacológico , Adesividade , Animais , Antiulcerosos/farmacologia , Varredura Diferencial de Calorimetria , Diosmina/farmacologia , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Duodeno/efeitos dos fármacos , Duodeno/patologia , Duodeno/ultraestrutura , Mucosa Gástrica/patologia , Mucosa Gástrica/ultraestrutura , Cinética , Masculino , Muco/química , NF-kappa B/metabolismo , Nanopartículas/ultraestrutura , Tamanho da Partícula , Ratos Sprague-Dawley , Espectroscopia de Infravermelho com Transformada de Fourier , Estômago/efeitos dos fármacos , Estômago/ultraestrutura , Úlcera/patologia , Difração de Raios X
6.
Carbohydr Polym ; 226: 115302, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31582049

RESUMO

Hydrogels could be promising wound healing dressings that maintain a moist environment in the wound site and accelerate wound healing. However, the lack of antibacterial effect, suitable mechanical property and adhesiveness limits their applications. Here, we designed a quaternized chitosan-Matrigel-polyacrylamide (QCS-M-PAM) hydrogel with multi-functions. The morphology, swelling ratio, mechanical test, antimicrobial property, hemostatic performance and biocompatibility of the hybrid hydrogel were investigated in vitro and vivo. The hybrid hydrogel showed a three-dimensional (3D) microporous structure, high swelling ratio, excellent stretchable and compressive property, similar modulus to human skin, good adhesiveness, and low cytotoxicity. The results of histology and molecular testing in vivo demonstrated that the hybrid hydrogel could significantly enhance wound healing, collagen deposition, and induce skin adnexal regeneration by upregulating anti-inflammatory factors, and downregulating proinflammatory factors. Together, the present antibacterial hydrogels with hemostatic and adhesive properties are considered to have promising potential used as wound dressings for full-thickness skin defect.


Assuntos
Resinas Acrílicas/farmacologia , Curativos Hidrocoloides , Quitosana/farmacologia , Colágeno/farmacologia , Hidrogéis/farmacologia , Laminina/farmacologia , Proteoglicanas/farmacologia , Cicatrização/efeitos dos fármacos , Resinas Acrílicas/química , Adesividade , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Células Cultivadas , Quitosana/química , Colágeno/química , Combinação de Medicamentos , Humanos , Hidrogéis/química , Laminina/química , Camundongos , Proteoglicanas/química , Cicatrização/fisiologia
7.
J Plant Physiol ; 243: 153054, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31648109

RESUMO

Adhesion of the barley husk to the underlying caryopsis requires the development of a cuticular cementing layer on the caryopsis surface. Differences in adhesion quality among genotypes have previously been correlated with cementing layer composition, which is thought to influence caryopsis cuticle permeability, the hypothesised mechanism of adhesion mediation. It is not yet known whether differences in adhesion quality among genotypes are determined by changes in caryopsis cuticle permeability. We examined changes in candidate cementing layer biosynthetic and regulatory genes to investigate the genetic mechanisms behind husk adhesion quality. We used both commercially relevant UK malting cultivars and older European lines to ensure phenotypic diversity in adhesion quality. An ethylene responsive transcription factor (NUD) is required for the development of the cementing layer. To examine correlations between gene expression, cementing layer permeability and husk adhesion quality we also treated cultivars with ethephon (2-chloroethylphosphonic acid) which breaks down to ethylene, and silver thiosulphate which inhibits ethylene reception, and measured caryopsis cuticle permeability. Differential adhesion qualities among genotypes are not determined by NUD expression during development of the cementing material alone, but could result from differences in biosynthetic gene expression during cementing layer development in response to longer-term NUD expression patterns. Altered caryopsis cuticle permeability does result in altered adhesion quality, but the correlation is not consistently positive or negative. Cuticle permeability is therefore not the mechanism that determines husk adhesion quality, but is likely a consequence of the required cuticular compositional changes that determine adhesion.


Assuntos
Etilenos/metabolismo , Hordeum/fisiologia , Compostos Organofosforados/farmacologia , Reguladores de Crescimento de Planta/farmacologia , Sementes/fisiologia , Tiossulfatos/farmacologia , Adesividade , Etilenos/antagonistas & inibidores , Expressão Gênica/fisiologia , Hordeum/genética , Permeabilidade , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sementes/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
8.
Int J Pharm ; 570: 118664, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31513871

RESUMO

The aim of this study was to develop a novel mucoadhesive cationic polymer by introducing primary amino groups to the polymeric backbone of starch. This newly synthesized polymer should exhibit superior properties over chitosan regarding solubility, mucoadhesiveness and cytotoxicity. Increasing amounts of sodium periodate were used to cleave and oxidize vicinal diols under aldehyde formation obtaining three different degrees of modification. In a subsequent step, primary amines were introduced via reductive amination with ammonia. Degree of amination was examined with TNBS-assay and zeta potential measurements. Mucoadhesiveness was investigated by rotating cylinder, tensile studies and rheological measurements. Primary amino groups were successfully attached to the polymer, proven by zeta potential measurements and UV-spectroscopy. Depending on the amount of periodate used in the reaction, coupling rates of up to 514 µmol/g polymer were achieved. All synthesized derivatives showed 100% solubility in a pH range of 1-9. Aminated starch with the highest coupling rate of 514 µmol/g showed a 9.5-fold prolonged retention time on intestinal mucosa and a 2.7-fold higher total work of adhesion on the mucosal tissue compared to chitosan. Furthermore, cytotoxic examinations of all tested polymers showed only a low impact on cell viability after 24 h, whereby starch derivatives possessed even less cell toxic effects than chitosan. Summarizing these results, cationic starch derivatives seem to be promising excipients for mucosal drug delivery with superior properties compared to chitosan, the most examined cationic polymer.


Assuntos
Adesivos/química , Cátions/química , Excipientes/química , Amido/química , Adesividade , Células CACO-2 , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quitosana/química , Sistemas de Liberação de Medicamentos/métodos , Humanos , Mucosa Intestinal/efeitos dos fármacos , Polímeros/química , Reologia , Solubilidade/efeitos dos fármacos
9.
Carbohydr Polym ; 225: 115110, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31521272

RESUMO

Various functional active hydrogels have been widely applied in tissue regeneration, especially in fields of wound repair as they are similar to the natural extracellular matrix (ECM) and can maintain moist at the wound site. However, preparing a hydrogel with multifunctional properties including high mechanical properties, excellent biocompatibility and long-term antibacterial activity is still a challenge. Herein, we developed a series of double network hydrogels based on poly (ethylene glycol) diacrylate (PEGDA) and chitosan (CS) or thiolated chitosan (TCS). The hydrogels presented in situ forming properties, good mechanical strength, adhesiveness, antibacterial activity and biocompatibility. The sample with the optimal formula of 15 wt% of PEGDA and 2 wt% of CS or TCS showed excellent mechanical adhesiveness, sustained release of antibacterial peptide and plasmid DNA, and it significantly accelerated in vivo wound healing process in a full-thickness skin defect model by reducing the inflammation and promoting the angiogenesis, meaning that the prepared hydrogels are excellent candidates for wound dressing.


Assuntos
Curativos Hidrocoloides , Quitosana/farmacologia , Hidrogéis/farmacologia , Polietilenoglicóis/farmacologia , Cicatrização , Adesividade , Animais , Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Ratos , Ratos Sprague-Dawley , Pele/efeitos dos fármacos
10.
Mater Sci Eng C Mater Biol Appl ; 105: 110140, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546402

RESUMO

Skin substitutes for deep wound healing require meticulous designing and fabrication to ensure proper structural and functional regeneration of the tissue. Range of physical and mechanical properties conducive for regeneration of different layers of skin is a prerequisite of an ideal scaffold. However, single or bilayer substitutes, lacking this feature, fail to heal full thickness wound. Complete scar free regeneration of skin is still a big challenge. This study reports fabrication of a trilayer scaffold, from biodegradable polymers that can provide the right ambience for simultaneous regeneration of all the three layers of skin. The scaffold was developed through optimization of different fabrication techniques, namely, casting, electrospinning and lyophilisation, for obtaining a tailored trilayer structure. It has mechanical strength similar to skin layers, can maintain a porosity-gradient and provides microenvironments suitable for simultaneous regeneration of epidermis, dermis and hypodermis. A co-culture model, of keratinocytes and dermal fibroblasts, confirms the efficiency of the scaffold in supporting proliferation and differentiation of different types of cells, into organized tissue. The scaffold showed improved and expedited wound healing in-vivo. Taken together, these compelling evidences successfully established the engineered trilayer scaffold as a promising template for skin tissue regeneration in case of deep wound.


Assuntos
Bioengenharia/métodos , Pele Artificial , Cicatrização , Adesividade , Animais , Materiais Biocompatíveis/farmacologia , Humanos , Interações Hidrofóbicas e Hidrofílicas , Ratos Sprague-Dawley , Tecidos Suporte/química , Cicatrização/efeitos dos fármacos
11.
Biomed Mater Eng ; 30(4): 439-448, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31476144

RESUMO

BACKGROUND: Adhesion strength of orthodontic attachments to enamel should be within optimal range to resist occlusal forces and to allow debonding without enamel damage. OBJECTIVE: The present study compared the effect of non-thermal plasma (NTP) and conventional surface treatment on the adhesion strength of orthodontic bracket to enamel. METHODS: A total of 100 premolar teeth were allocated into 5 groups according to the bonding procedure followed: Group 1 (Etch, prime and composite adhesive); Group 2 (Prime and composite adhesive); Group 3 (Glass ionomer cement); Group 4 (NTP, prime and composite adhesive) and Group 5 (NTP and glass ionomer cement). Ten specimens in each group were subjected to artificial aging and the remaining ten specimens served as baseline specimens. Adhesion strength values were recorded after debonding and bond failure types were scored. Water contact angles of the NTP treated and untreated enamel surface were measured. RESULTS: Group 1 specimen demonstrated highest bond strength at baseline (21.5 ± 3.01) and thermocycling (15.8 ± 2.87) and the least values were in Group 2 specimens at baseline (3.9 ± 1.01) and thermocycling (1.6 ± 0.7). Among the experimental (NTP) groups, Group 4 specimens exhibited high adhesion strength at baseline (10.2 ± 1.76) and after thermocycling (9.8 ± 2.15) compared to Group 5 specimens at baseline (10.1 ± 1.05) and thermocycling (6.5 ± 2.19). The water contact angle on untreated enamel surface was 53.1° ± 2.1° as compared to 1.4° ± 0.7° in treated surface. CONCLUSION: Non-thermal plasma (NTP) treatment in conjunction with composite adhesives demonstrated clinically acceptable adhesion strength and was well within the optimal range (7-14 MPa) for enamel bonding.


Assuntos
Adesivos/química , Esmalte Dentário/química , Braquetes Ortodônticos , Adesividade , Análise do Estresse Dentário , Retenção de Dentadura/efeitos adversos , Cimentos de Ionômeros de Vidro/química , Humanos , Teste de Materiais , Braquetes Ortodônticos/efeitos adversos , Gases em Plasma , Cimentos de Resina/química
12.
Mater Sci Eng C Mater Biol Appl ; 104: 109873, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500054

RESUMO

A chitosan-pectin (CS-PEC) biopolymeric hydrogel wound dressing was investigated for lidocaine delivery. Here we demonstrate for the first time the feasibility of three-dimensional (3D) printed CS-PEC hydrogel incorporating the local anaesthetic drug lidocaine hydrochloride (LDC) as a potential wound dressing candidate. The hydrogels were prepared by physical crosslinking of CS and PEC polysaccharides. The scaffolds were printed using an extrusion-based 3D printer using a mechanical positive displacement dispensing system followed by lyophilisation. The 3D printed hydrogels showed good printability, dimensional integrity and self-adhesion to skin. The high swelling ratio and water absorption of 3D printed hydrogels indicated suitability for absorbing exudates and maintaining a moist wound healing environment. Fourier transform infrared (FTIR) spectroscopy results indicated that the CS-PEC hydrogel was formed by hydrogen bonds. Incorporation of LDC in the hydrogel did not interfere with its functional stability. In vitro drug release studies of LDC over 6 h fitted the Korsmeyer-Peppas model. This work demonstrates the possibility of a 3D printed hydrogel as a suitable candidate for wound dressings.


Assuntos
Bandagens , Quitosana/química , Sistemas de Liberação de Medicamentos , Hidrogéis/química , Lidocaína/farmacologia , Pectinas/química , Impressão Tridimensional , Adesividade , Varredura Diferencial de Calorimetria , Liberação Controlada de Fármacos , Estudos de Viabilidade , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Tecidos Suporte/química , Água
13.
Int J Nanomedicine ; 14: 5271-5285, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31409989

RESUMO

Electrospun nanofibers have been widely studied for many medical applications. They can be designed with specific features, including mucoadhesive properties. This review summarizes the polymeric scaffolds obtained by the electrospinning process that has been applied for drug release in different mucosal sites such as oral, ocular, gastroenteric, vaginal, and nasal. We analyzed the electrospinning parameters that have to be optimized to create reproducible and efficient mucoadhesive nanofibers, among them are: electrical field, polymer concentration, viscosity, flow rate, needle-collector distance, solution conductivity, solvent, environmental parameters, and electrospinning setup. We also revised the mucoadhesive theories as well as the mucoadhesive properties of the polymers used. This review shows that the most studied mucosal site is the oral cavity, because it is accessible and easy to evaluate, while the rest are uncomfortable for the patient and difficult to assess in vivo. We found problems that need to be solved for mucoadhesive electrospun nanofibers, such as improving adhesion strength and mucosal permanence time, and the design of unidirectional release, multilayer systems for the treatment of several pathologies, to ensure the drug concentration in the tissue or target organ.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Muco/química , Nanofibras/química , Polímeros/química , Adesividade , Condutividade Elétrica , Humanos
14.
Adv Mater ; 31(40): e1901826, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31402514

RESUMO

A notable challenge for the design of engineered living materials (ELMs) is programming a cellular system to assimilate resources from its surroundings and convert them into macroscopic materials with specific functions. Here, an ELM that uses Escherichia coli as its cellular chassis and engineered curli nanofibers as its extracellular matrix component is demonstrated. Cell-laden hydrogels are created by concentrating curli-producing cultures. The rheological properties of the living hydrogels are modulated by genetically encoded factors and processing steps. The hydrogels have the ability to grow and self-renew when placed under conditions that facilitate cell growth. Genetic programming enables the gels to be customized to interact with different tissues of the gastrointestinal tract selectively. This work lays a foundation for the application of ELMs with therapeutic functions and extended residence times in the gut.


Assuntos
Materiais Biocompatíveis/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Engenharia Genética , Hidrogéis/metabolismo , Adesividade , Materiais Biocompatíveis/química , Hidrogéis/química , Nanofibras/química
15.
Int J Nanomedicine ; 14: 6001-6018, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31447554

RESUMO

Background: The gastroretentive drug delivery system is an effective administration route, which can improve the bioavailability of the drug and the therapeutic effect by prolonging the release time of the drug and controlling the release rate in the stomach. Methods: Inspired by the excellent adhesion properties of mussel protein, we prepared novel catechol-grafted chitosan alginate/barium sulfate microcapsules (Cat-CA/BS MCs) with mucoadhesive properties and computed tomography (CT) imaging function for gastric drug delivery. First, barium sulfate nanoclusters used as CT contrast agent were synthesized in situ in the Cat-CA/BS MCs through a one-step electronic spinning method. Next, catechol-grafted chitosan as the mucoadhesive moiety was coated on the surface of Cat-CA/BS MCs by polyelectrolyte molecule self-assembly. Results: The prepared Cat-CA/BS MCs could effectively retained in the stomach for 48 hours and successively released ranitidine hydrochloride, which could be used for the treatment of gastric ulcer. Cat-CA/BS MCs exhibited superior CT contrast imaging properties for real-time tracking in vivo after oral administration. Conclusion: These findings demonstrate that Cat-CA/BS MCs serving as multifunctional oral drug carriers possess huge potential in gastroretentive drug delivery and non-invasive visualization.


Assuntos
Sulfato de Bário/química , Cápsulas/química , Catecóis/farmacologia , Quitosana/química , Sistemas de Liberação de Medicamentos , Estômago/efeitos dos fármacos , Estômago/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adesividade , Administração Oral , Animais , Preparações de Ação Retardada/farmacologia , Portadores de Fármacos , Feminino , Camundongos Endogâmicos C57BL , Muco/química , Nanopartículas/química , Nanopartículas/ultraestrutura , Ranitidina/farmacologia , Espectroscopia de Luz Próxima ao Infravermelho , Estômago/patologia
16.
Adv Mater ; 31(37): e1903446, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31339196

RESUMO

On-skin electronics require conductive, porous, and stretchable materials for a stable operation with minimal invasiveness to the human body. However, porous elastic conductors that simultaneously achieve high conductivity, good stretchability, and durability are rare owing to the lack of proper design for good adhesion between porous elastic polymer and conductive metallic networks. Here, a simple fabrication approach for porous nanomesh-type elastic conductors is shown by designing a layer-by-layer structure of nanofibers/nanowires (NFs/NWs) via interfacial hydrogen bonding. The as-prepared conductors, consisting of Ag NWs and polyurethane (PU) NFs, simultaneously achieve high conductivity (9190 S cm-1 ), high stretchability (310%), and good durability (82% resistance increase after 1000 cycles of deformation at 70% tensile strain). The direct contact between the Ag NWs enables the high conductivity. The synergistic effect of the layer-by-layer structure and good adhesion between the Ag NWs and the PU NFs enables good mechanical properties. Furthermore, without any adhesive gel/tape, the conductors can be utilized as breathable strain sensors for precise joint motion monitoring, and as breathable sensing electrodes for continuous electrophysiological signal recording.


Assuntos
Elasticidade , Nanofibras/química , Nanofios/química , Poliuretanos/química , Prata/química , Adesividade , Condutividade Elétrica , Ligações de Hidrogênio , Modelos Moleculares , Conformação Molecular , Porosidade , Resistência à Tração
17.
Int J Biol Macromol ; 138: 831-836, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31351956

RESUMO

To reduce animal testing, there is a need to develop novel in-vitro models for evaluating the retention of bioactive compounds in food and pharmaceutical products. Here, a mucus-mimetic platform was developed through a one-step approach based on encapsulating mucin within alginate gel beads. We found that mucins form micron sized aggregates distributed across the surface of the calcium-alginate bead, as shown by environmental scanning electron microscopy (ESEM). Retention of bioactive compounds on the mucin-functionalised surface was tested using a commercial orange drink formulation. To aid flavour retention, different mucoadhesive polymers with varying charge, including anionic, neutral and strongly cationic, were tested for their ability to interact with mucin and aid retaining flavour compounds within the mucin-alginate bead. The alginate-mucin mucus mimic was validated using an ex-vivo bovine tongue, with the flavour retention results showing qualitative agreement. The developed method proved to be a convenient, efficient tool for providing information on the effectiveness of mucoadhesive polymers without variability, safety and sustainability issues associated with an ex-vivo or in-vivo system. We propose that by encapsulating other relevant oral proteins, alongside mucins, current gaps between in-vitro and the ex-vivo systems may be narrowed.


Assuntos
Alginatos/química , Mucinas/química , Adesividade , Alginatos/metabolismo , Animais , Fenômenos Químicos , Cromatografia Gasosa-Espectrometria de Massas , Mucinas/metabolismo , Muco/metabolismo , Suínos
18.
Carbohydr Polym ; 222: 115014, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31320045

RESUMO

The films based on carboxymethyl derivatives of starch (CMS) and cellulose (CMC) were proposed as a novel human skin equivalent. The physicochemical properties (moisture absorption, solubility in water, mechanical properties) of CMS/CMC films were evaluated. Additionally, some properties were compared to the human skin ones (surface roughness, tribology). The system based on CMS/CMC 25/75 wt. % was selected for testing the adhesive properties of pressure-sensitive adhesives commonly used for medical purposes (acrylic, silicone and polyisobutylene). Similar tests were performed for human skin. The peel adhesion values for CMS/CMC film and human skin were similar for all adhesives types tested. Applying such a skin equivalent allows to evaluate the functional properties of medical pressure-sensitive adhesives without the ethical and economic issues.


Assuntos
Adesivos/química , Carboximetilcelulose Sódica/química , Pele Artificial , Amido/análogos & derivados , Resinas Acrílicas/química , Adesividade , Humanos , Interações Hidrofóbicas e Hidrofílicas , Polienos/química , Polímeros/química , Silicones/química , Amido/química , Resistência à Tração
19.
Biomed Res Int ; 2019: 1851740, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31275963

RESUMO

The human opportunistic fungal pathogen Candida albicans causes a severe health burden while the biofilms formed by C. albicans present a kind of infections that are hard to cure, highlighting the pressing need for new antifungal drugs against C. albicans. This study was to explore the antifungal activities of lycorine hydrochloride (LH) against C. albicans. The minimal inhibitory concentration (MIC) of LH against C. albicans SC5314 was 64 µM. Below its MIC, LH demonstrated antivirulence property by suppressing adhesion, filamentation, biofilm formation, and development, as well as the production of extracellular phospholipase and exopolymeric substances (EPS). The cytotoxicity of LH against mammalian cells was low, with half maximal inhibitory concentrations (IC50) above 256 µM. Moreover, LH showed a synergistic effect with AmB, although its interaction with fluconazole, as well as caspofungin, was indifferent. Thus, our study reports the potential use of LH, alone or in combination with current antifungal drugs, to fight C. albicans infections.


Assuntos
Alcaloides de Amaryllidaceae/farmacologia , Candida albicans/patogenicidade , Fenantridinas/farmacologia , Adesividade/efeitos dos fármacos , Alcaloides de Amaryllidaceae/química , Alcaloides de Amaryllidaceae/toxicidade , Antifúngicos/química , Antifúngicos/farmacologia , Antifúngicos/toxicidade , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Candida albicans/fisiologia , Morte Celular/efeitos dos fármacos , AMP Cíclico/metabolismo , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Hifas/efeitos dos fármacos , Fenantridinas/química , Fenantridinas/toxicidade , Fosfolipases/metabolismo , Virulência/efeitos dos fármacos
20.
Carbohydr Polym ; 218: 343-354, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31221339

RESUMO

Taxifolin possesses gastroprotective property but is characterized by low water solubility, is instabile in alkaline medium, and is degraded by the intestinal bacteria flora. The purpose of the work was therefore to produce a gastroadhesive formulation to prolong taxifolin residence time and release in the stomach. We first demonstrated that taxifolin is stable in simulated gastric fluid with or without pepsin and mucus, and is able to cross pig gastric mucus layer and stomach mucosa. Next, gastromucoadhesive microparticles composed of Syloid® AL-1 mesoporous silica, chitosan and HPMC were produced using spray-drying. Microparticles were characterized by a spherical shape and a mean volume-equivalent diameter around 12 µm. The optimized microparticles were able to release taxifolin and to adhere to pig stomach mucosa for 5 h.


Assuntos
Quitosana/química , Portadores de Fármacos/química , Fármacos Gastrointestinais/química , Quercetina/análogos & derivados , Adesividade , Animais , Liberação Controlada de Fármacos , Excipientes/química , Mucosa Gástrica/metabolismo , Microtecnologia , Mimusops/química , Tamanho da Partícula , Permeabilidade , Quercetina/química , Sementes/química , Dióxido de Silício/química , Suínos
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