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1.
Food Chem ; 335: 127629, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32736156

RESUMO

Folate deficiencies are prevalent in countries with insufficient food diversity. Rice fortification is seen as a viable way to improve the daily intake of folates. This work reports an efficient process of rice fortification involving ultrasonic treatment and absorption of the folic acid fortificant. Increased porosity due to sonication allowed the efficient absorption of folic acid into the brown rice kernel up to 5.195 × 104 µg/100 g, a 1,982-fold increase from its inherent content. The absorbed folic acid in brown rice has 93.53% retention after washing and cooking. Fortification of ultrasound-treated milled rice with folic acid was also efficient affording 6.559 × 104 µg/100 g, a 4,054-fold increase from its basal content. The effect of fortification caused a decrease in the thermal and pasting temperatures. The fortification also caused yellow coloration, decrease in hardness, and increase in the adhesiveness of the rice. The resulting fortified brown rice showed improved textural properties favorable for consumers.


Assuntos
Absorção Fisico-Química , Ácido Fólico/química , Alimentos Fortificados/análise , Oryza/química , Ondas Ultrassônicas , Adesividade , Cor , Dureza
2.
Int J Nanomedicine ; 15: 7861-7875, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33116505

RESUMO

Purpose: The topically administered drugs through conventional delivery systems have low bioavailability. Henceforth, the present study was designed to prepare and optimize clarithromycin (CTM)-loaded chitosan nanoparticles (CHNPs) to demonstrate the efficacy against microorganisms. Methods: Clarithromycin-loaded chitosan nanoparticles (CTM-CHNPs) were prepared by ionotropic gelation method. The formulation was optimized by box-Behnken design using the formulation variables like CH (A), STPP concentration (B), and stirring speed (C). Their effects were evaluated on the independent variables like particle size (Y1) and entrapment efficiency (Y2). Further, CTM-CHNPs were evaluated for physicochemical parameters, in-vitro drug release, ex-vivo permeation, bioadhesive study, corneal hydration, histopathology, HET-CAM, and antibacterial study. Results: The optimized formulation (CTM-CHNPopt) showed the low particle size (152±5 nm), which is desirable for ocular delivery. It also showed high encapsulation (70.05%), zeta potential (+35.2 mV), and was found in a spherical shape. The drug release study revealed a sustained drug release profile (82.98±3.5% in 12 hours) with Korsmeyer peppas kinetic (R2=0.996) release model. It showed a 2.7-fold higher corneal permeation than CTM-solution. CHNPs did not exhibit any sign of damage to excised goat cornea, which is confirmed by hydration, histopathology, and HET-CAM test. It exhibited significant (P<0.05) higher antibacterial susceptibility than CTM-solution. Conclusion: The finding of the study concluded that CTM-CHNPs can be used for effective management of bacterial conjunctivitis by increasing the precorneal residence time.


Assuntos
Quitosana/química , Claritromicina/química , Claritromicina/farmacologia , Portadores de Fármacos/química , Olho/efeitos dos fármacos , Nanopartículas/química , Adesividade , Animais , Antibacterianos/efeitos adversos , Antibacterianos/química , Antibacterianos/farmacologia , Claritromicina/efeitos adversos , Preparações de Ação Retardada , Composição de Medicamentos , Tamanho da Partícula
3.
Nature ; 585(7825): 383-389, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32939070

RESUMO

Insect eyes have an anti-reflective coating, owing to nanostructures on the corneal surface creating a gradient of refractive index between that of air and that of the lens material1,2. These nanocoatings have also been shown to provide anti-adhesive functionality3. The morphology of corneal nanocoatings are very diverse in arthropods, with nipple-like structures that can be organized into arrays or fused into ridge-like structures4. This diversity can be attributed to a reaction-diffusion mechanism4 and patterning principles developed by Alan Turing5, which have applications in numerous biological settings6. The nanocoatings on insect corneas are one example of such Turing patterns, and the first known example of nanoscale Turing patterns4. Here we demonstrate a clear link between the morphology and function of the nanocoatings on Drosophila corneas. We find that nanocoatings that consist of individual protrusions have better anti-reflective properties, whereas partially merged structures have better anti-adhesion properties. We use biochemical analysis and genetic modification techniques to reverse engineer the protein Retinin and corneal waxes as the building blocks of the nanostructures. In the context of Turing patterns, these building blocks fulfil the roles of activator and inhibitor, respectively. We then establish low-cost production of Retinin, and mix this synthetic protein with waxes to forward engineer various artificial nanocoatings with insect-like morphology and anti-adhesive or anti-reflective function. Our combined reverse- and forward-engineering approach thus provides a way to economically produce functional nanostructured coatings from biodegradable materials.


Assuntos
Bioengenharia , Córnea/anatomia & histologia , Córnea/fisiologia , Proteínas de Drosophila/química , Drosophila/anatomia & histologia , Proteínas do Olho/química , Nanoestruturas/química , Ceras/química , Adesividade , Análise de Variância , Animais , Córnea/química , Difusão , Drosophila/química , Drosophila/classificação , Drosophila/genética , Proteínas de Drosophila/deficiência , Proteínas de Drosophila/genética , Proteínas do Olho/genética , Técnicas de Silenciamento de Genes , Nanomedicina , Ligação Proteica , Engenharia de Proteínas , Dobramento de Proteína
4.
Braz Oral Res ; 34: e105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32876118

RESUMO

The aim of this research was to evaluate the influence of MDP (10-methacryloyloxydecyl dihydrogen phosphate) concentration and application mode of experimental adhesives on microshear bond strength (µSBS) to dentin after storage in distilled water at 37°C for 24h and 6 months. Five experimental adhesives were prepared with: CQ, DABE, BHT, ethanol, HEMA, TEGDMA, Bis-EMA, UDMA, and Bis-GMA. Concentrations of 0 wt%, 3 wt%, 9 wt%, 12 wt% or 15 wt% of MDP were added to their composition. The adhesives were applied to flat dentin surfaces in etch-and-rinse or self-etching modes. Cylindrical molds filled with light-cured composite resin were placed above the dentin. The specimens were stored in distilled water at 37oC for 24h or 6 months and submitted to µSBS testing. The adhesives were also submitted to pH analysis. The data were analyzed by one-way ANOVA, three-way ANOVA and Tukey's test (α = 5%). All the adhesives used in the etch-and-rinse mode showed significantly higher bond strength than the adhesives applied in the self-etching approach. The 9 wt% adhesive showed the highest bond strength values, and 3 wt% was most stable after storage. A strong negative correlation between MDP concentration and pH was observed. It was concluded that the formulations with low concentrations of MDP (up to 9 wt%) showed better results for bond strength and bond strength degradation over time.


Assuntos
Colagem Dentária , Adesividade , Resinas Compostas , Cimentos Dentários , Dentina , Adesivos Dentinários , Teste de Materiais , Cimentos de Resina , Resistência à Tração
5.
Yakugaku Zasshi ; 140(9): 1175-1183, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32879249

RESUMO

The mock patches were prepared with novel acrylic polymers as adhesive layer where biphenyl-4-ylacetic acid (BAA) or 2-(2-fluorobiphenyl-4-yl) propanoic acid (FPA) was used as model active pharmaceutical ingredients (APIs). In addition, the mock patches were formulated with typical ester ingredients for transdermal dosage forms. The molecular state of the model APIs in the adhesive layer was observed by polarized microscope and microscopic Raman spectroscopy, which contains both conventional and low frequency (LF) region. Crystallization behavior would be depended on the interaction between API and polymers in the adhesive layer. In particular, LF Raman measurement was useful to discriminate API polymorphs. The pharmaceutical properties including dissolution and skin permeation of APIs were also evaluated for mock patches. The drug release and transdermal permeation were enhanced with the ester ingredients such as isopropyl myristate and diethyl sebacate due to their diffusion to the test solution or the skin stratum corneum as well as reducing the interaction between API and polymers. Further, the tack strength was not changed, but the peel strength was weakened by the additives. Thus, the adhesive properties were controllable by formulation with the additives. These findings could enable to evaluate the interaction between API and the polymers for adhesive layer and select the appropriate polymer and additives for used APIs when designing the drug products.


Assuntos
Anti-Inflamatórios não Esteroides/administração & dosagem , Polímeros , Adesivo Transdérmico , Adesividade , Administração Cutânea , Ácidos Decanoicos , Liberação Controlada de Fármacos , Miristatos , Fenilacetatos/administração & dosagem , Fenilacetatos/metabolismo , Propionatos/administração & dosagem , Propionatos/metabolismo , Absorção Cutânea , Solubilidade , Análise Espectral Raman
6.
Int J Nanomedicine ; 15: 4001-4020, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606661

RESUMO

Background: Simvastatin (SMV), a hypocholesterolemic agent, suffers from very low bioavailability due to its poor aqueous solubility and extensive first-pass metabolism. Methods: Two SMV carrier systems, namely, polymeric drug inclusion complex (IC) and mixed micelles (MM) nanoparticles, were developed and loaded into mucoadhesive buccal films to enhance SMV bioavailability. The two carrier systems were characterized and their permeation across human oral epithelial cells (OEC) was studied. The effect of IC to MM ratio (X1) and the mucoadhesive polymer concentration (X2) on the cumulative percent of drug released, elongation percent and the mucoadhesive strength, from the prepared mucoadhesive films, were optimized. Ex vivo permeation across bovine mucosal tissue was investigated. The permeation parameters for the in vitro and ex vivo release data were calculated. Results: Complexation of SMV with hydroxypropyl beta-cyclodextrin (HP ß-CD) was superior to all other polymers as revealed by the equilibrium saturation solubility, stability constant, complexation efficiency and thermodynamic potential. SMV-HP ß-CD IC was utilized to develop a saturated polymeric drug solution. Both carrier systems showed enhanced permeation across OEC when compared to pure drug. X1 and X2 were significantly affecting the characteristics of the prepared films. The optimized mucoadhesive buccal film formulation loaded with SMV IC and drug MM nanoparticles demonstrated superior ex vivo permeation when compared to the corresponding pure drug buccal film, and the calculated permeation parameters confirmed this finding. Conclusion: Mucoadhesive buccal films containing SMV IC and drug MM can be used to improve drug bioavailability; however, additional pharmacokinetic and pharmacodynamic studies are required.


Assuntos
Portadores de Fármacos/química , Liberação Controlada de Fármacos , Mucosa Bucal/efeitos dos fármacos , Muco/química , Sinvastatina/farmacologia , 2-Hidroxipropil-beta-Ciclodextrina/química , Adesividade , Animais , Varredura Diferencial de Calorimetria , Bovinos , Sistemas de Liberação de Medicamentos , Humanos , Nanopartículas/química , Nanopartículas/ultraestrutura , Permeabilidade , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
7.
BMC Oral Health ; 20(1): 180, 2020 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-32600325

RESUMO

BACKGROUND: Bonded retainers are widely used as they are esthetically pleasing, easily acceptable, provide greater stability, compliance free and causes no soft tissue irritation and speech problems. Though, fracture and bond failure are their shortcomings. Therefore, the objectives of this study were to evaluate the number of bond failures and type of failure pattern between two types of mandibular canine-canine bonded retainers. METHODS: Total 60 subjects were recruited initially and were assessed for eligibility, out of which 6 were excluded and 2 were lost to follow up. They were randomly divided into two groups. Fiber reinforced composite (FRC) retainers were inserted in group 1 subjects while group 2 subjects received multistranded stainless steel (MSW) retainers. The subjects were recalled after every 3 months over a period of 1 year. Bond failure rate and failure pattern based on adhesive remnant index were evaluated at each visit. The bond failure rate and failure pattern were compared between the two retainers by using Chi-square test. RESULTS: The bond failure rates were 42.94% for FRC retainer and 31.41% for MSW retainer. Hence, total number of bond failures in both retainers were 37.17%. The difference of bond failure between two groups was statistically significant (p = 0.012). Type "0" failure pattern was detected commonly with both types of retainers (p <  0.001). CONCLUSION: Our findings indicate that multistranded stainless steel wire retainer is a superior option to be used for fixed lingual retention in mandibular arch as it exhibited lower bond failure as compared to fiber reinforced composite retainer. Adhesive failure is the most common type of bond failure observed with both types of fixed retainers. TRIAL REGISTRATION: ID NCT03881813 ( https://clinicaltrials.gov/ ); March 19, 2019, retrospective registration.


Assuntos
Colagem Dentária/métodos , Materiais Dentários/química , Desenho de Aparelho Ortodôntico , Contenções Ortodônticas , Adesividade , Adulto , Dente Canino/anatomia & histologia , Esmalte Dentário , Feminino , Humanos , Masculino , Aparelhos Ortodônticos Fixos , Fios Ortodônticos , Estudos Retrospectivos
8.
Int J Nanomedicine ; 15: 4079-4090, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606665

RESUMO

Purpose: The aim of this study is to develop efficient localized therapy of sertaconazole nitrate for the treatment of vaginal candidiasis. Methods: Sertaconazole nitrate-loaded cationic liposomes were prepared by thin-film hydration method and coated with different concentrations of pectin (0.05%, 0.1% and 0.2%) to develop mucoadhesive liposomes. The formulated mucoadhesive vesicles were characterized in terms of morphology, entrapment efficiency, particle size, zeta value, mucoadhesive properties and drug release. The selected formula was incorporated into a gel base and further characterized by an ex vivo permeation study in comparison with conventional sertaconazole gel. Also, the in vivo study was performed to assess the efficacy of sertaconazole mucoadhesive liposomal gel in treating rats with vaginal candidiasis. Results: The mucoadhesive liposomes were spherical. Coating liposomes with pectin results in increased entrapment efficiency and particle size compared with uncoated vesicles. On the contrary, zeta values were reduced upon coating liposomes with pectin indicating efficient coating of liposomes with pectin. Mucoadhesive liposomes showed a more prolonged and sustained drug release compared with uncoated liposomes. Ex vivo study results showed that mucoadhesive liposomal gel increased sertaconazole tissue retention and reduced drug tissue penetration. In the invivo study, the mucoadhesive liposomal gel showed a significant reduction in the microbial count with a subsequent reduction in inflammatory responses with the lowest histopathological change compared with conventional gel. Conclusion: The study confirmed the potentiality of employing mucoadhesive liposomes as a successful carrier for the vaginal delivery of antifungal drugs.


Assuntos
Antifúngicos/uso terapêutico , Candidíase Vulvovaginal/tratamento farmacológico , Imidazóis/uso terapêutico , Muco/química , Tiofenos/uso terapêutico , Adesividade , Animais , Anti-Infecciosos/farmacologia , Biomarcadores/metabolismo , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Feminino , Géis , Humanos , Imidazóis/farmacologia , Imunoglobulina G/metabolismo , Imunoglobulina M/metabolismo , Mediadores da Inflamação/metabolismo , Lipossomos/ultraestrutura , Mucinas/metabolismo , Tamanho da Partícula , Ratos Sprague-Dawley , Ovinos , Eletricidade Estática , Tiofenos/farmacologia , Vagina/patologia , beta-Glucanas/metabolismo
9.
Sci Rep ; 10(1): 9395, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32523030

RESUMO

Aquatic insects living in fast-flowing streams have developed various types of attachment systems to resist being carried away by strong currents. Combinations of various attachment devices offer aquatic insects advantages in underwater adhesion on substrates with different surface properties. In this study, the net-winged midge (Blepharicera sp.) larvae were investigated to understand micro-/nano-structural attachment mechanisms. The hierarchical structure of insect adhesive surfaces was characterized using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Centrifugal measurements were also conducted to measure the critical rotational velocity at which the larvae of Blepharicera sp. can adhere to substrates with varying roughness. Commercial suckers require smooth substrate surface to maintain a pressure that is lower than the surrounding pressure for adhesion under the sucker cup while the suckers of net-winged midge larvae possess hierarchical micro-/nano-structures, which attach closely to rough surfaces underwater. Furthermore, the functions of microstructures observed on the sucker, including wrinkled surface, inward setae, outer fibers, and nick were explored and may contribute to underwater adhesion. The aligned C-shaped suckers can attach and detach effectively by closing or opening the gap. The unique microstructure and adhesion capability of such suckers could shed light on the design and synthesis of novel bio-inspired devices for reversible underwater adhesion.


Assuntos
Chironomidae/fisiologia , Extremidades/fisiologia , Larva/fisiologia , Adesividade , Animais , Insetos/fisiologia , Microscopia Eletrônica de Varredura/métodos , Sensilas/fisiologia , Propriedades de Superfície
10.
Aliment Pharmacol Ther ; 52(3): 442-448, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32548849

RESUMO

BACKGROUND: We have previously shown, ex vivo, that alginate solutions can have a topical protective effect on oesophageal mucosal biopsies exposed to simulated gastric juice. Oesophageal mucosal impedance can measure the duration of mucosal adherence of ionic solutions since the impedance drops when the solution is present, and rises to baseline as the solution clears. AIM: To investigate the in vivo duration of adhesion of swallowed alginate solution to distal oesophageal mucosa. METHODS: We studied 20 healthy volunteers and 10 patients with heartburn. A pH-impedance catheter was inserted, and baseline distal channel oesophageal impedance measured. Healthy volunteers received 10 mL of either sodium alginate (Gaviscon Advance), Gaviscon placebo (no alginate) or viscous slurry (saline mixed with sucralose), given in a randomised, single-blinded order over three visits. Patients received either sodium alginate or placebo on two visits. Initial impedance drop was measured, then 1-minute mean impedance was measured each minute until ≥75% recovery to baseline. RESULTS: In healthy volunteers, sodium alginate adhered to the oesophageal mucosa for longer than placebo or viscous slurry (10.4 [8.7] minutes vs 1.1 [1.6] vs 3.6 [4.0], P < 0.01). In patients, sodium alginate adhered to the oesophageal mucosa for longer than placebo (9.0 (5.4) vs 3.7 (4.1), P < 0.01). CONCLUSIONS: Sodium alginate solution adhered to the oesophageal mucosa for significantly longer than placebo or viscous slurry. This demonstrates that alginates could confer a protective benefit due to mucoadhesion and can be a basis for further development of topical protectants and for topical drug delivery in oesophageal disease.


Assuntos
Alginatos/farmacologia , Mucosa Esofágica/metabolismo , Azia/tratamento farmacológico , Adesividade , Administração Oral , Administração Tópica , Adulto , Feminino , Azia/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade
11.
Proc Natl Acad Sci U S A ; 117(27): 15497-15503, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32576692

RESUMO

Bioadhesives such as tissue adhesives, hemostatic agents, and tissue sealants have potential advantages over sutures and staples for wound closure, hemostasis, and integration of implantable devices onto wet tissues. However, existing bioadhesives display several limitations including slow adhesion formation, weak bonding, low biocompatibility, poor mechanical match with tissues, and/or lack of triggerable benign detachment. Here, we report a bioadhesive that can form instant tough adhesion on various wet dynamic tissues and can be benignly detached from the adhered tissues on demand with a biocompatible triggering solution. The adhesion of the bioadhesive relies on the removal of interfacial water from the tissue surface, followed by physical and covalent cross-linking with the tissue surface. The triggerable detachment of the bioadhesive results from the cleavage of bioadhesive's cross-links with the tissue surface by the triggering solution. After it is adhered to wet tissues, the bioadhesive becomes a tough hydrogel with mechanical compliance and stretchability comparable with those of soft tissues. We validate in vivo biocompatibility of the bioadhesive and the triggering solution in a rat model and demonstrate potential applications of the bioadhesive with triggerable benign detachment in ex vivo porcine models.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Ferida Cirúrgica/terapia , Adesivos Teciduais/química , Adesividade , Animais , Reagentes para Ligações Cruzadas/química , Modelos Animais de Doenças , Feminino , Teste de Materiais , Ratos , Bicarbonato de Sódio/química , Soluções , Succinimidas/química , Suínos , Técnicas de Fechamento de Ferimentos/instrumentação
12.
AAPS PharmSciTech ; 21(5): 142, 2020 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-32419061

RESUMO

Mucoadhesion-based drug delivery systems have recently gained interest because of their bio-adhesion capability, which results in enhanced residence time leading to prolonged duration of action with the mucosal surface, potentially improving compliance and convenience. Mucoadhesion testing of these formulations is widely reported; however, this is technically challenging due to the absence of any standard methods and difficulty in conducting mucoadhesion, formulation-mucosal surface interaction, mucosal surface topography and drug release in a single experiment. As these measurements are currently conducted separately, on replicate formulations, results can often be subjective and difficult to correlate. Hence, the aim of the present study was to develop a new AFM-based single-entity ex vivo muco-dissolution (MUCO-DIS) technique to simultaneously evaluate mucoadhesion force, 3D surface topography, polymer dissolution and drug release characteristics. To demonstrate the potential of the current technique, the interactions between model pectin microparticles containing metformin HCl and a range of gastrointestinal mucosal surfaces (gastric, small intestine, large intestine and buccal) were studied. This novel system has not only successfully determined the mucoadhesion force, polymer dissolution and drug release information but has also highlighted the difference in microparticle performance with different mucosal targets. The current work has highlighted the potential of this newly developed MUCO-DIS system and we believe this will be a valuable tool for characterising these popular pharmaceutical formulations. This technique could also provide an opportunity to other scientific fields to evaluate materials, substrate behaviour and their interactions in their hydrated state at nanoscale with real-time chemical and surface mapping.


Assuntos
Absorção Intestinal , Microscopia de Força Atômica/métodos , Membrana Mucosa , Nanotecnologia/métodos , Adesividade , Animais , Composição de Medicamentos , Sistemas de Liberação de Medicamentos , Excipientes , Técnicas In Vitro , Metformina/administração & dosagem , Metformina/química , Nanopartículas , Solubilidade , Suínos
13.
PLoS One ; 15(5): e0233013, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32413086

RESUMO

Global trade and climate change are re-shaping the distribution map of pandemic pathogens. One major emerging concern is Xylella fastidiosa, a tropical bacterium recently introduced into Europe from America. In last decades, X. fastidiosa was detected in several European countries. X. fastidiosa is an insect vector-transmitted bacterial plant pathogen associated with severe diseases in a wide range of hosts. X. fastidiosa through a tight coordination of the adherent biofilm and the planktonic states, invades the host systemically. The planktonic phase is correlated to low cell density and vessel colonization. Increase in cell density triggers a quorum sensing system based on mixture of cis 2-enoic fatty acids-diffusible signalling factors (DSF) that promote stickiness and biofilm. The lipidome profile of Olea europaea L. (cv. Ogliarola salentina) samples, collected in groves located in infected zones and uninfected zones was performed. The untargeted analysis of the lipid profiles of Olive Quick Decline Syndrome (OQDS) positive (+) and negative (-) plants showed a clustering of OQDS+ plants apart from OQDS-. The targeted lipids profile of plants OQDS+ and OQDS- identified a shortlist of 10 lipids that increase their amount in OQDS+ and X. fastidiosa positive olive trees. These lipid entities, provided to X. fastidiosa subsp. pauca pure culture, impact on the dual phase, e.g. planktonic ↔ biofilm. This study provides novel insights on OQDS lipid hallmarks and on molecules that might modulate biofilm phase in X. fastidiosa subsp. pauca.


Assuntos
Metabolismo dos Lipídeos , Olea/metabolismo , Olea/microbiologia , Doenças das Plantas/microbiologia , Xylella/fisiologia , Xylella/patogenicidade , Adesividade , Animais , Biofilmes/crescimento & desenvolvimento , Interações entre Hospedeiro e Microrganismos/fisiologia , Insetos Vetores/microbiologia , Itália , Lipidômica , Percepção de Quorum/fisiologia
14.
Proc Biol Sci ; 287(1926): 20200123, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32370666

RESUMO

Remarkable progress has been made characterizing one of nature's most integrated, hierarchical structures--the fibrillar adhesive system of geckos. Nonetheless, we lack an understanding of how multiple toes coordinate to facilitate geckos' acrobatic locomotion. Here, we tested the control function of gecko toes by running them on vertical substrates varying in orientation, friction and roughness. Sideways wall-running geckos realigned the toes of their top feet upward to resist gravity. Toe contact area was not compromised, but redistributed. Geckos aligned all toes upward to resist slipping when encountering low-friction patches during sideways wall-running. Negotiation of intermittent slippery strips showed an increased contribution of particular toes to compensate for toes that lost adhesion. Increasing substrate roughness using discrete rods perpendicular to sideways locomotion resulted in geckos bending and/or rotating toes to conform to and even grasp the rods, with potential forces more than five times body weight. Geckos increase their effectiveness of manoeuvrability in demanding environments by taking advantage of the distributed control afforded by multiple toes. Our findings provide insight on biological attachment and offer inspiration to advance gecko-inspired robotics and other biomimetic applications.


Assuntos
Lagartos/anatomia & histologia , Dedos do Pé , Adesividade , Animais , Fenômenos Biomecânicos , Fricção , Lagartos/fisiologia , Locomoção , Modelos Biológicos , Corrida , Propriedades de Superfície
15.
Carbohydr Polym ; 235: 115953, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32122489

RESUMO

Adhesion loss of hydrocolloid wound dressings is ubiquitous clinical problem, which seriously reduces the therapeutic efficiency and patient experience. In order to address this problem, the clarification on adhesion loss mechanism and the development of effective alternatives of commercial hydrocolloid dressings are urgent and inevitable. Herein, adhesion loss mechanism of hydrocolloid dressings was investigated using sodium carboxymethyl cellulose (CMC)-filled hydrocolloid dressings exposing to physiological environment as model. The adhesion mechanism and contact angle tests were combined to obtain surface energy of dressings. The results indicated that the dissolution, swelling and exudation of CMC occurred successively (concentration reached 1.607 g/L after 10 h). The effused CMC led to the dramatic increase in surface energy (from 14.5-80.7 mN/m) and adhesion loss appeared. This work explored the origin of adhesion loss of hydrocolloid wound dressings and might promote the designing of hydrocolloid dressings with both excellent humidity control and sustained self-adhesiveness.


Assuntos
Curativos Hidrocoloides , Carboximetilcelulose Sódica/química , Curativos Oclusivos , Pele/química , Adesividade , Humanos , Tamanho da Partícula , Propriedades de Superfície , Aderências Teciduais , Cicatrização
16.
Acta Neurochir (Wien) ; 162(4): 737-743, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32034495

RESUMO

BACKGROUND: Watertight closure of the dura mater is fundamental in neurosurgery. Besides the classical suturing techniques, a variety of biomaterials have been proposed as sealants. Platelet rich fibrin (PRF) is an autologous biomaterial which can readily be obtained through low-speed centrifugation of patient's own blood. It is rich in fibrin, growth factors, leucocytes and cytokines and has shown adhesive properties while promoting the physiological wound healing process. In this study, we investigated the effect of applying PRF in reinforcing the watertight dura mater closure. METHODS: We created an in vitro testing device, where the watertight dura mater closure could be hydrostatically assessed. On 26 fresh harvested bovine dura maters, a standardised 20-mm incision was closed with a running suture, and the leak pressure was measured first without (primary leak pressure) and then with PRF augmentation (secondary leak pressure). The two groups of measurements have been statistically analysed with the Student's paired t test. RESULTS: The "running suture only group" had a leak pressure of 10.5 ± 1.2 cmH2O (mean ± SD) while the "PRF-augmented group" had a leak pressure of 47.2 ± 2.6 cm H2O. This difference was statistically significant (p < 0.001; paired t test). CONCLUSIONS: Autologous platelet rich fibrin augmentation reliably reinforced watertight closure of the dura mater to a > 4-fold increased leak pressure after failure of the initial standard running suture technique.


Assuntos
Materiais Biocompatíveis/uso terapêutico , Dura-Máter/cirurgia , Fibrina Rica em Plaquetas , Técnicas de Fechamento de Ferimentos , Adesividade , Animais , Bovinos , Vazamento de Líquido Cefalorraquidiano/prevenção & controle , Feminino , Adesivo Tecidual de Fibrina , Procedimentos Neurocirúrgicos , Pressão , Técnicas de Sutura , Suturas
17.
Mar Drugs ; 18(2)2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32023890

RESUMO

Topical administration of drugs into the vagina can provide local therapy of vaginal infections, preventing the possible systemic side effects of the drugs. The natural polysaccharide chitosan is known for its excellent mucoadhesive properties, safety profile, and antibacterial effects, and thus it can be utilized in improving localized vaginal therapy by prolonging the residence time of a drug at the vaginal site while acting as an antimicrobial in synergy. Therefore, we aimed to explore the potential of chitosan, namely chitosan-coated liposomes and chitosan hydrogel, as an excipient with intrinsic antimicrobial properties. Liposomes were prepared by the thin-film hydration method followed by vesicle size reduction by sonication to the desired size, approximately 200 nm, and coated with chitosan (0.01, 0.03, 0.1, and 0.3%, w/v, respectively). The mucoadhesive properties of chitosan-coated liposomes were determined through their binding efficiency to mucin compared to non-coated liposomes. Non-coated liposomal suspensions were incorporated in chitosan hydrogels forming the liposomes-in-hydrogel formulations, which were further assessed for their texture properties in the presence of biological fluid simulants. The antibacterial effect of chitosan-coated liposomes (0.03%, 0.1% and 0.3%, w/v) and chitosan hydrogels (0.1% and 0.3%, w/w) on Staphylococcus epidermidis and Staphylococcus aureus was successfully confirmed.


Assuntos
Antibacterianos/química , Quitosana/química , Excipientes/química , Adesividade , Administração Intravaginal , Animais , Antibacterianos/farmacologia , Quitosana/farmacologia , Feminino , Humanos , Hidrogéis , Lipossomos , Tamanho da Partícula , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Suínos
18.
Sensors (Basel) ; 20(4)2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32069937

RESUMO

Wearable health-monitoring systems should be comfortable, non-stigmatizing, and able to achieve high data quality. Smart textiles with electronic elements integrated directly into fabrics offer a way to embed sensors into clothing seamlessly to serve these purposes. In this work, we demonstrate the feasibility of electrocardiogram (ECG) monitoring with sewn textile electrodes instead of traditional gel electrodes in a 3-lead, chest-mounted configuration. The textile electrodes are sewn with silver-coated thread in an overlapping zig zag pattern into an inextensible fabric. Sensor validation included ECG monitoring and comfort surveys with human subjects, stretch testing, and wash cycling. The electrodes were tested with the BIOPAC MP160 ECG data acquisition module. Sensors were placed on 8 subjects (5 males and 3 females) with double-sided tape. To detect differences in R peak detectability between traditional and sewn sensors, effect size was set at 10% of a sample mean for heart rate (HR) and R-R interval. Paired student's t-tests were run between adhesive and sewn electrode data for R-R interval and average HR, and a Wilcoxon signed-rank test was run for comfort. No statistically significant difference was found between the traditional and textile electrodes (R-R interval: t = 1.43, p > 0.1; HR: t = - 0.70, p > 0.5; comfort: V = 15,p > 0.5).


Assuntos
Eletrocardiografia , Têxteis , Dispositivos Eletrônicos Vestíveis , Adesividade , Impedância Elétrica , Eletrodos , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Maleabilidade
19.
Acta Pharm ; 70(3): 359-371, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32074072

RESUMO

Films for buccal application are a slowly emerging new platform for drug delivery. There remains a lack of analytical techniques for the determination of in vitro active pharmaceutical ingredient release. The aim here was to develop an alternative method to the commonly used United States Pharmacopoeia (USP) 2 method, based on the flow-through cell. This system extends the release time and enables more detailed sample discrimination according to formulation. It could be used as a tool for in vivo prediction of drug release rates from buccal film formulations. The flow cell contains two chambers separated by a membrane through which the released active pharmaceutical ingredient is measured. Vital system variables and their effects on the release rate of the model active pharmaceutical ingredient are presented for formulations based on sodium alginate polymer. The method reflects the differences between films and is shown to be discriminatory for evaluation of buccal formulations.


Assuntos
Alginatos/química , Sistemas de Liberação de Medicamentos , Preparações Farmacêuticas/química , Adesividade , Administração Bucal , Química Farmacêutica/métodos , Liberação Controlada de Fármacos , Preparações Farmacêuticas/administração & dosagem , Polímeros/química
20.
Drug Res (Stuttg) ; 70(2-03): 97-100, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31968367

RESUMO

In many cases the nasal cavity is the gateway for the infection; it necessitates the development of a drug for nasal administration with antiviral, adsorptive and protective properties. Gels were chosen as an optimal dosage form. The study is aimed at studying the properties of biopolymer gelling agents and determining the composition of the future dosage form. MATERIALS AND METHODS: Gel samples with 3, 4 and 5% concentrations were prepared using the following gelling agents: sodium alginate Protanal CR8223, Protanal CR8133, Manucol LKÐ¥ (FMC BioPolymer) and xanthan gum GrinstedXanthan (DuPontDanisco), Xanthural 180 (CP Kelco). Adsorption and osmotic activity, bioadhesion and thermostability of the samples were determined. RESULTS: Basing on the totality of the obtained results, 3 compositions prospective for the dosage form development were selected: xanthan gums (particle size 180pm) from various manufacturers: Grinsted Xanthan 3 and 4% concentrations, Xanthural 180 5% concentration. These compositions possess high adsorption activity (25.06; 21.35; 20.6 g respectively), optimal osmotic activity (155, 171, 100%) and have significant bioadhesion (28.4421; 22.7237; 30.2835 N) that allows the drug to stay in the nasal cavity for a long period of time. All selected compositions demonstrated good high-temperature stability. CONCLUSION: The obtained data shows prospects of applying the samples for the development of nasal gel with an immunobiological substance.


Assuntos
Biopolímeros/química , Excipientes/química , Polissacarídeos Bacterianos/química , Adesividade , Administração Intranasal , Adsorção , Química Farmacêutica , Estabilidade de Medicamentos , Géis , Temperatura Alta , Cavidade Nasal/metabolismo , Osmose , Tamanho da Partícula
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