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1.
Crit Rev Food Sci Nutr ; : 1-27, 2022 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-35943179

RESUMEN

The natural bioactive or nutraceuticals exhibit several health benefits, including anti-inflammatory, anti-cancer, metal chelation, antiviral, and antimicrobial activity. The inherent limitation of nutraceuticals or bioactive ligand(s) in terms of poor pharmacokinetic and other physicochemical properties affects their overall therapeutic efficiency. The excess of iron in the physiological compartments and its varying dynamic oxidation state [Fe(II) and Fe(III)] precipitates various clinical conditions such as non-transferrin bound iron (NTBI), labile iron pool (LIP), ferroptosis, cancer, etc. Though several natural bioactive ligands are proposed to chelate iron, the efficiency of bioactive ligands is limited due to poor bioavailability, denticity, and other related physicochemical properties. The present review provides insight into the relevance of studying the dynamic oxidation state of iron(II) and iron(III) in the physiological compartments and its clinical significance for selecting diagnostics and therapeutic regimes. We suggested a three-pronged approach, i.e., diagnosis, selection of therapeutic regime (natural bioactive), and integration of novel drug delivery systems (NDDS) or nanotechnology-based principles. This systematic approach improves the overall therapeutic efficiency of natural iron chelators to manage iron overload-related clinical conditions.

2.
ACS Appl Bio Mater ; 7(8): 5411-5422, 2024 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-38996006

RESUMEN

3D printing can revolutionize personalized medicine by allowing cost-effective, customized tissue-engineering constructs. However, the limited availability and diversity of biopolymeric hydrogels restrict the variety and applications of bioinks. In this study, we introduce a composite bioink for 3D bioprinting, combining a photo-cross-linkable derivative of Mucin (Mu) called Methacrylated Mucin (MuMA) and Hyaluronic acid (HA). The less explored Mucin is responsible for the hydrogel nature of mucus and holds the potential to be used as a bioink material because of its plethora of features. HA, a crucial extracellular matrix component, is mucoadhesive and enhances ink viscosity and printability. Photo-cross-linking with 405 nm light stabilizes the printed scaffolds without damaging cells. Rheological tests reveal shear-thinning behavior, aiding cell protection during printing and improved MuMA bioink viscosity by adding HA. The printed structures exhibited porous behavior conducive to nutrient transport and cell migration. After 4 weeks in phosphate-buffered saline, the scaffolds retain 70% of their mass, highlighting stability. Biocompatibility tests with lung epithelial cells (L-132) confirm cell attachment and growth, suggesting suitability for lung tissue engineering. It is envisioned that the versatility of bioink could lead to significant advancements in lung tissue engineering and various other biomedical applications.


Asunto(s)
Materiales Biocompatibles , Bioimpresión , Ácido Hialurónico , Ensayo de Materiales , Mucinas , Impresión Tridimensional , Ingeniería de Tejidos , Ácido Hialurónico/química , Ácido Hialurónico/farmacología , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Humanos , Mucinas/química , Mucinas/metabolismo , Tinta , Luz , Pulmón/citología , Tamaño de la Partícula , Andamios del Tejido/química , Hidrogeles/química , Hidrogeles/farmacología
3.
ACS Appl Bio Mater ; 7(3): 1671-1681, 2024 03 18.
Artículo en Inglés | MEDLINE | ID: mdl-38447193

RESUMEN

Copper sulfide nanoparticles (CuS) hold tremendous potential for applications in photothermal therapy (PTT) and photoacoustic imaging (PAI). However, the conventional chemical coprecipitation method often leads to particle agglomeration issues. To overcome this challenge, we utilized polyvinylpyrrolidone (PVP) as a stabilizing agent, resulting in the synthesis of small PVP-CuS nanoparticles named PC10, PCK30, and PC40. Our study aimed to investigate how different molecular weights of PVP influence the nanoparticles' crystalline characteristics and essential properties, especially their photoacoustic and photothermal responses. While prior research on PVP-assisted CuS nanoparticles has been conducted, our study delves deeper into this area, providing insights into optical properties. Remarkably, all synthesized nanoparticles exhibited a crystalline structure, were smaller than 10 nm, and featured an absorbance peak at 1020 nm, indicating their robust photoacoustic and photothermal capabilities. Among these nanoparticles, PC10 emerged as the standout performer, displaying superior photoacoustic properties. Our photothermal experiments demonstrated significant temperature increases in all cases, with PC10 achieving an impressive efficiency of 51%. Moreover, cytotoxicity assays revealed the nanoparticles' compatibility with cells, coupled with an enhanced incidence of apoptosis compared to necrosis. These findings underscore the promising potential of PVP-stabilized CuS nanoparticles for advanced cancer theranostics.


Asunto(s)
Nanopartículas , Neoplasias , Humanos , Povidona , Peso Molecular , Fototerapia , Neoplasias/diagnóstico por imagen , Neoplasias/terapia , Nanopartículas/uso terapéutico
4.
Cureus ; 16(5): e61202, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38939302

RESUMEN

Maxillary osteomyelitis is a rare bone infection and is rarer to come across with the advent of advanced antibiotic therapies. It is often linked to immunocompromised conditions, namely diabetes mellitus, cancer, and chronic alcoholism, as they increase the chances of developing osteomyelitis. We present a rare case of maxillary osteomyelitis along with an infraorbital abscess in a 32-year-old male patient with uncontrolled diabetes. The patient complained of dental pain, facial swelling, and visual disturbances. The patient was managed with sequestrectomy along with curettage, incision, and drainage of orbital abscess. The patient responded well to surgery and had no complications post-surgery. As radiographic signs may present late, the authors aim to highlight the significance of thorough clinical examination and good patient history. Prompt radical treatment is necessary to avoid any severe consequences.

5.
Sci Rep ; 14(1): 20300, 2024 08 31.
Artículo en Inglés | MEDLINE | ID: mdl-39217210

RESUMEN

Rampant industrialization has led to widespread reliance on hydrocarbon polymers for various commercial applications. While these synthetic polymers, commonly known as plastics, degrade in slowly in the environments, the toxic effects of their micro-sized particles remain underexplored. In this study, we synthesized polyisobutylene (PIB) microparticles in the lab and evaluated their toxicity and accumulation in a zebrafish model. Pristine and fluorescent PIB-microplastics (MPs), with particle sizes ranging from 2 to 10 µm, were synthesized using the solvent evaporation method. Fourier-transform infrared spectroscopy (FTIR) confirmed the stability of the suspensions. Zebrafish larvae exposed to various concentrations of PIB-MPs exhibited numerous morphological and molecular changes, including delayed hatching, impaired swimming behavior, increased reactive oxygen species levels, altered mRNA levels of genes encoding antioxidant proteins, and reduced survival rates. Dissections revealed PIB-MP accumulation in the guts of larvae and adult fish within 7-21 days, causing damage to the intestinal mucosa. These findings provide insights into how contaminants like PIB can induce pathophysiological defects in aquatic fauna and pose potential health hazards to humans.


Asunto(s)
Homeostasis , Larva , Polímeros , Pez Cebra , Animales , Pez Cebra/metabolismo , Polímeros/química , Larva/efectos de los fármacos , Larva/metabolismo , Homeostasis/efectos de los fármacos , Microplásticos/toxicidad , Especies Reactivas de Oxígeno/metabolismo , Tamaño de la Partícula , Contaminantes Químicos del Agua/toxicidad , Polienos
6.
ACS Biomater Sci Eng ; 9(7): 4208-4222, 2023 07 10.
Artículo en Inglés | MEDLINE | ID: mdl-37294579

RESUMEN

This study reports the novel use of Achatina fulica (A. fulica) mucus as a potential therapeutic repair agent in osteoarthritis and cartilage tissue repair in vitro. Snail mucus was isolated, sterilized, and characterized using FTIR, XPS, rheology, and LC-MS/MS. The GAGs, sugar, phenol, and protein contents were estimated using standard assays. The LC-MS/MS identified 6-gingerol and some other small molecules. The effects of the sterilized mucus were studied on human chondrocytes using the C28/I2 cell as a model for the in vitro assays. The MTT assay indicates that mucus extracted from the pedal of A. fulica is biocompatible with the cells up to a concentration of 50 µg/mL. The mucus promoted cell migration and proliferation and completely closed the wound within 72 h, as indicated in the in vitro scratch assay. In addition, the snail mucus reduced apoptosis significantly (p < 0.05) in the treated cells by 74.6%. It preserved the cytoskeletal integrity of the C28/I2 cells, attributed mainly to GAGs and 6-gingerol content of the mucus. In conclusion, this present study suggests that GAGs and 6-gingerol conferred wound-healing and antiapoptotic properties on the mucus secretion from A. fulica and can be explored for therapeutic repair and cartilage tissue engineering.


Asunto(s)
Materiales Biocompatibles , Condrocitos , Animales , Humanos , Cromatografía Liquida , Espectrometría de Masas en Tándem , Caracoles , Moco/metabolismo
7.
Cureus ; 15(9): e46299, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37915876

RESUMEN

This review focuses on the fact that oral disorders are not merely localized to the mouth; in a broader sense, they also have a more significant impact on systemic health. In this review, we tried to bring to the notice various complications of periodontitis on the body's major organ systems. It has also been suggested that there is a potential connection between periodontitis and certain systemic disorders. Reviewing this fascinating topic is necessary. The objective is to create a thorough body of knowledge on the subject that is simple to access, alert medical professionals to the connection between dental health and systemic health, and highlight the necessity of a more thorough incorporation of medical and dental training. Periodontitis is a probable risk factor for various problems connected to the cardiovascular, pulmonary, endocrine, musculoskeletal, central nervous, and reproductive systems. It is a continual likely source of infection. Oral health affects overall health, and if extensive healthcare is ever accomplished, dental health should never be considered a distinct, remote, and lower significant part of health wholly disconnected from quality of life. One should never underestimate oral disorders as being acute and always curable. People should take utmost care and take the condition seriously to prevent significant complications.

8.
Infect Genet Evol ; 111: 105432, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37030587

RESUMEN

Outbreaks of HFMD in children aged <5 years have been reported worldwide and the major causative agents are Coxsackievirus (CV) A16, enterovirus (EV)-A71 and recently CVA6. In India, HFMD is a disease that is not commonly reported. The purpose of the study was to identify the enterovirus type(s) associated with large outbreak of Hand, foot, and mouth disease during COVID-19 pandemic in 2022. Four hundred and twenty five clinical samples from 196-suspected cases were collected from different parts of the country. This finding indicated the emergence of CVA6 in HFMD along with CVA16, soon after the gradual easing of non-pharmaceutical interventions during-pandemic COVID-19 and the relevance of continued surveillance of circulating enterovirus types in the post-COVID pandemic era.


Asunto(s)
COVID-19 , Infecciones por Enterovirus , Enterovirus , Enfermedad de Boca, Mano y Pie , Niño , Humanos , Enfermedad de Boca, Mano y Pie/epidemiología , Pandemias , COVID-19/epidemiología , Enterovirus/genética , Infecciones por Enterovirus/epidemiología , Brotes de Enfermedades , India/epidemiología , China/epidemiología
9.
Anal Biochem ; 416(1): 39-44, 2011 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-21640699

RESUMEN

Detergents are commonly used in protein-chemistry protocols and may be necessary for protein extraction, solubilization, and denaturation; however, their presence interferes with many downstream analysis techniques, including mass spectrometry (MS). To enable downstream analysis, it is critical to remove unbound detergents from protein and peptide samples. In this study, we describe a high-performance resin that offers exceptional detergent removal for proteins and peptides. When used in a spin column format, this resin dramatically improves protein and peptide MS results by more than 95% removal of 1-5% detergents, including sodium dodecyl sulfate (SDS), sodium deoxycholate, Chaps, Triton X-100, Triton X-114, NP-40, Brij-35, octyl glucoside, octyl thioglucoside, and lauryl maltoside, with high recovery of proteins and peptides. Postcolumn liquid chromatography-tandem MS (LC-MS/MS) analysis of trypsin digests of bovine serum albumin (BSA) and HeLa cell lysate revealed excellent sequence coverage, indicating successful removal of detergent from the peptides. Matrix-assisted laser desorption/ionization (MALDI)-MS analysis of unprocessed and processed samples further confirmed efficient removal of detergents. The advantages of this method include speed (<15min), efficient detergent removal, and high recovery of proteins and peptides.


Asunto(s)
Fraccionamiento Químico/instrumentación , Detergentes/aislamiento & purificación , Oligosacáridos/química , Péptidos/química , Proteínas/química , Resinas Sintéticas/química , Animales , Bovinos , Cromatografía Liquida , Células HeLa , Humanos , Espectrometría de Masas , Albúmina Sérica Bovina/química , Propiedades de Superficie , Tripsina/química
10.
Int J Biol Macromol ; 192: 180-196, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-34619273

RESUMEN

The current study reports the preparation of lignin grafted temperature and pH responsive hydrogels through copolymerization of N-isopropylacrylamide, acrylic acid and varying amount of lignin methacrylate (LMA = 50, 100, 150 and 200 mg) as crosslinker adopting radical polymerization technique. Functional group and structural characterizations were carried out to confirm hydrogels synthesis and their network structure. The variation in pore size on addition of lignin revealed the tuning of pores as well as swelling capacity of the hydrogels by suitable amount of LMA. All LMA grafted hydrogels showed temperature responsive behavior and pH dependent sensitivity in swelling, with reduced equilibrium swelling capacity values compared to sample without lignin. In alkali medium at room temperature, the maximum swelling capacity with 48% higher retention was noticed, while a significant reduction in swelling was observed at 40 °C in all media. The addition of lignin still preserved the tensile strength up to 100 kPa and compressive load bearing ability up to 30 kPa in freeze dried state with adequate interfacial stress transfer. An increase in lignin concentration showed enhanced storage modulus (~two-fold increase), adequate loss modulus values and improved cell viability, which paves the way for possible biomedical applications.


Asunto(s)
Álcalis/química , Hidrogeles/química , Lignina/química , Metacrilatos/química , Materiales Biocompatibles/química , Fenómenos Químicos , Concentración de Iones de Hidrógeno , Espectroscopía de Resonancia Magnética , Fenómenos Mecánicos , Estructura Molecular , Polímeros/química , Porosidad , Análisis Espectral , Temperatura , Termogravimetría
11.
Carbohydr Polym ; 261: 117893, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33766378

RESUMEN

Glycosylated pH-sensitive mesoporous silica nanoparticles (MSNs) of capecitabine (CAP) were developed for targeting colorectal cancer. The MSNs possessed an average pore diameter of 8.12 ± 0.43 nm, pore volume of 0.73 ± 0.21 cm3/g, and particle size of 245.24 ± 5.75 nm. A high loading of 180.51 ± 5.23 mg/g attributed to the larger pore volume was observed. The surface of the drug-loaded MSNs were capped with chitosan-glucuronic acid (CHS-GCA) conjugate to combine two strategies viz. pH-sensitive, and lectin receptor mediated uptake. In vitro studies demonstrated a pH-sensitive and controlled release of CAP which was further enhanced in the presence of rat caecal content. Higher uptake of the (CAP-MSN)CHS-GCA was observed in HCT 116 cell lines. The glycosylated nanoparticles revealed reduction in the tumors, aberrant crypt foci, dysplasia and inflammation, and alleviation in the toxic features. This illustrated that the nanoparticles showed promising antitumor efficacy with reduced toxicity and may be used as a effective carrier against cancer.


Asunto(s)
Capecitabina/administración & dosificación , Quitosano/química , Neoplasias Colorrectales/tratamiento farmacológico , Portadores de Fármacos/síntesis química , Ácido Glucurónico/química , Dióxido de Silicio/química , Animales , Capecitabina/farmacocinética , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/uso terapéutico , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Preparaciones de Acción Retardada/síntesis química , Preparaciones de Acción Retardada/química , Preparaciones de Acción Retardada/uso terapéutico , Portadores de Fármacos/química , Portadores de Fármacos/uso terapéutico , Sistemas de Liberación de Medicamentos , Liberación de Fármacos , Femenino , Células HCT116 , Humanos , Concentración de Iones de Hidrógeno , Nanopartículas/química , Nanopartículas/uso terapéutico , Tamaño de la Partícula , Porosidad , Ratas , Ratas Wistar , Ensayos Antitumor por Modelo de Xenoinjerto
12.
AAPS PharmSciTech ; 11(1): 322-35, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20182824

RESUMEN

The present study was designed to improve the bioavailability of forskolin by the influence of precorneal residence time and dissolution characteristics. Nanosizing is an advanced approach to overcome the issue of poor aqueous solubility of active pharmaceutical ingredients. Forskolin nanocrystals have been successfully manufactured and stabilized by poloxamer 407. These nanocrystals have been characterized in terms of particle size by scanning electron microscopy and dynamic light scattering. By formulating Noveon AA-1 polycarbophil/poloxamer 407 platforms, at specific concentrations, it was possible to obtain a pH and thermoreversible gel with a pH(gel)/T (gel) close to eye pH/temperature. The addition of forskolin nanocrystals did not alter the gelation properties of Noveon AA-1 polycarbophil/poloxamer 407 and nanocrystal properties of forskolin. The formulation was stable over a period of 6 months at room temperature. In vitro release experiments indicated that the optimized platform was able to prolong and control forskolin release for more than 5 h. The in vivo studies on dexamethasone-induced glaucomatous rabbits indicated that the intraocular pressure lowering efficacy for nanosuspension/hydrogel systems was 31% and lasted for 12 h, which is significantly better than the effect of traditional eye suspension (18%, 4-6 h). Hence, our investigations successfully prove that the pH and thermoreversible polymeric in situ gel-forming nanosuspension with ability of controlled drug release exhibits a greater potential for glaucoma therapy.


Asunto(s)
Sistemas de Liberación de Medicamentos/métodos , Geles/química , Glaucoma/tratamiento farmacológico , Poloxámero/administración & dosificación , Poloxámero/química , Resinas Acrílicas , Animales , Disponibilidad Biológica , Química Farmacéutica , Colforsina , Preparaciones de Acción Retardada/química , Ojo/metabolismo , Masculino , Conejos , Solubilidad , Temperatura
13.
Int J Biol Macromol ; 163: 2224-2235, 2020 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-32918957

RESUMEN

Biopolymers-based nanoparticles delivery emerged alternatively to improve nutraceuticals and drug bioavailability. The intestinal physiology suggested a prerequisite of lipid moiety for carotenoid absorption. This study aimed to fabricate chitosan-based nanoparticles with phosphatidylcholine (PC) to enhance lutein bioavailability. Lutein encapsulated chitosan nanoparticles with PC (LCNPC) or without PC (LCN) were assessed for bioaccessibility, sustain release, cellular uptake/internalization, and basolateral secretion of lutein in Caco-2 cells. Standard lutein mixed micelles (LMM), and micelles derived through in vitro digestion of green leafy vegetables (GMM) treated as controls. The LCNPC showed reduced particle size, higher colloidal stability, homogeneous dispersion, and suitable for oral administration compared to LCN. The cellular uptake of lutein (20 h) in LCNPC was higher than LCN, LMM, and GMM, respectively. Interestingly, lutein uptake was maximum at 8 h in LMM and gradually decreased against sustain-release response in LCNPC and LCN, whereas considerably low lutein uptake from GMM at all time points. Further, LCNPC significantly increased basolateral secretion of triglyceride (TG) and positively correlated enhanced lutein uptake/internalization process than LCN and micelles. Also, LCNPC demonstrated the upregulation of endocytosis, paracellular, scavenger receptor class B type 1 (SRB-1), and peroxisome proliferator-activated receptor gamma (PPARγ) mediated lutein transport mechanism. These results suggested that fabrication of biopolymer-based nanoparticles with PC could provide greater insight to improve lutein bioavailability at enterocyte levels, to avoid age-related macular degeneration and other chronic diseases.


Asunto(s)
Disponibilidad Biológica , Quitosano/química , Luteína/farmacología , Nanopartículas/química , Biopolímeros/química , Biopolímeros/farmacología , Células CACO-2 , Quitosano/farmacología , Humanos , Luteína/química , Fosfatidilcolinas/química , Fosfatidilcolinas/farmacología
14.
Biomed Mater Eng ; 14(4): 581-92, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15472405

RESUMEN

An easy method to crystallize homogenous HAP at physiological pH as well as powders of HAP and CPP at low temperature are described. Platy and spherulitic crystals of HAP were crystallized at the physiological pH using single diffusion method. Well-defined platy crystals of hydroxyapatite were obtained at the physiological temperature and pH. These crystals were found to be pure and homogenous form of HAP without any contamination from the crystallizing medium. Spherulitic crystals of HAP of approximately 3 mm in diameter were obtained in the presence of Fe at 47 degrees C. A sol-gel technique involving agarose is described for the preparation of hydroxyapatite and calcium pyrophosphate. Pure form of HAP was synthesised at 85 degrees C and its sintering properties were also studied. At a temperature of 1200 degrees C, the material gets completely converted to alpha-calcium pyrophosphate. The samples were analysed by XRD, IR, TGA and SEM. The particle size of the synthesised powders was measured using the dynamic light scattering experiments.


Asunto(s)
Materiales Biocompatibles/química , Cristalización/métodos , Durapatita/química , Temperatura , Concentración de Iones de Hidrógeno , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Polvos , Propiedades de Superficie
15.
Chem Commun (Camb) ; 49(47): 5390-2, 2013 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-23652460

RESUMEN

Hollow microcapsules capable of disintegrating in response to dual biological stimuli have been synthesized from two FDA approved drug molecules. The capsules fabricated from protamine and chondroitin sulphate disintegrate in the presence of either trypsin or hyaluronidase enzymes, which are documented to be simultaneously over-expressed under some pathological conditions.


Asunto(s)
Sulfatos de Condroitina/química , Sistemas de Liberación de Medicamentos , Hialuronoglucosaminidasa/química , Protaminas/química , Tripsina/química , Carbonato de Calcio/química , Cápsulas , Poliestirenos/química
16.
Chem Commun (Camb) ; 48(17): 2307-9, 2012 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-22266910

RESUMEN

Biologically triggered exploding microcapsules were synthesized by layer-by-layer assembly of biopolymers. The microcapsules showed controlled rupturing behaviour upon exposure to a pathologically relevant biomolecule, trypsin. These microcapsules offer significant potential for clinical applications.


Asunto(s)
Cápsulas/química , Portadores de Fármacos/química , Tripsina/metabolismo , Biopolímeros/química , Concentración de Iones de Hidrógeno , Tripsina/química
17.
Colloids Surf B Biointerfaces ; 84(2): 379-83, 2011 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-21333503

RESUMEN

We are reporting a novel green approach to incorporate silver nanoparticles (NPs) selectively in the polyelectrolyte capsule shell for remote opening of polyelectrolyte capsules. This approach involves in situ reduction of silver nitrate to silver NPs using PEG as a reducing agent (polyol reduction method). These nanostructured capsules were prepared via layer by layer (LbL) assembly of poly(allylamine hydrochloride) (PAH) and dextran sulfate (DS) on silica template followed by the synthesis of silver NPs and subsequently the dissolution of the silica core. The size of silver nanoparticles synthesized was 60±20 nm which increased to 100±20 nm when the concentration of AgNO(3) increased from 25 mM to 50 mM. The incorporated silver NPs induced rupture and deformation of the capsules under laser irradiation. This method has advantages over other conventional methods involving chemical agents that are associated with cytotoxicity in biological applications such as drug delivery and catalysis.


Asunto(s)
Cápsulas/química , Nanopartículas del Metal/química , Plata/química , Técnicas Químicas Combinatorias , Electrólitos/química , Microscopía de Fuerza Atómica , Modelos Biológicos , Polímeros/química
18.
J Hazard Mater ; 195: 214-22, 2011 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-21880417

RESUMEN

Degradation of dimethoate under UV irradiation using TiO(2)/polymer films prepared by the layer-by-layer (LbL) method was investigated. The thin films were fabricated on glass slides and the surface morphology and roughness of the thin films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The effect of lamp intensity, catalyst loading in the layers, number of bilayers, pH and initial dimethoate concentration on the degradation of dimethoate was systematically studied. The degradation was monitored using high performance liquid chromatography (HPLC) analysis and total organic carbon (TOC) measurements as a function of irradiation time, to see the change in concentration of dimethoate and mineralization, respectively. Complete degradation of dimethoate was achieved under TiO(2) optimum loading of 4 g/L at an UV irradiation time of 180 min. Increase in the lamp intensity, catalyst loading and number of bilayers increased the rate of degradation. At a pH of 4.62, complete degradation of dimethoate was observed. The degradation efficiency decreased with increase in initial dimethoate concentration. The degradation byproducts were analyzed and confirmed by gas chromatography-mass spectra (GC-MS). Toxicity of the irradiated samples was measured using the luminescence of bacteria Vibrio fischeri after 30 min of incubation and the results showed more toxicity than the parent compound. Catalyst reusability studies revealed that the fabricated thin films could be repeatedly used for up to ten times without affecting the photocatalytic activity of the films. The findings of the present study are very useful for the treatment of wastewaters contaminated with pesticides.


Asunto(s)
Dimetoato/química , Polímeros/química , Titanio/química , Aliivibrio fischeri/efectos de los fármacos , Catálisis , Cromatografía Líquida de Alta Presión , Dimetoato/toxicidad , Cromatografía de Gases y Espectrometría de Masas , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Fotoquímica , Difracción de Rayos X
19.
Colloids Surf B Biointerfaces ; 78(2): 266-74, 2010 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-20400274

RESUMEN

A reversible drug delivery system based on spontaneous deposition of a model protein into preformed microcapsules has been demonstrated for protein delivery applications. Layer-by-Layer assembly of poly(allylamine hydrochloride) (PAH) and poly(methacrylic acid) (PMA) onto polystyrene sulfonate (PSS) doped CaCO3 particles, followed by core removal yielded intact hollow microcapsules having a unique property to induce spontaneous deposition of bovine serum albumin (BSA) at pH below its isoelectric point of 4.8, where it was positively charged. These capsules showed reversible pH dependent open and closed states to fluorescence labeled dextran (FITC-Dextran) and BSA (FITC-BSA). The loading capacity of BSA increased from 9.1 x 10(7) to 2.03 x 10(8) molecules per capsule with decrease in pH from 4.5 to 3. The loading of BSA-FITC was observed by confocal laser scanning microscopy (CLSM), which showed homogeneous distribution of protein inside the capsule. Efficient loading of BSA was further confirmed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The interior capsule concentration was as high as 209 times the feeding concentration when the feeding concentration was increased from 1 to 10 mg/ml. The deposition was initially controlled by spontaneous loading mechanism at lower BSA concentration followed by diffusion controlled loading at higher concentration; which decreased the loading efficiency from 35% to 7%. Circular dichroism (CD) measurements and Fourier transform infrared spectroscopy (FTIR) confirmed that there was no significant change in conformation of released BSA in comparison with native BSA. The release was initially burst in the first 0.5 h and sustained up to 5 h. The hollow capsules were found to be biocompatible with mouse embryonic fibroblast (MEF) cells during in vitro cell culture studies. Thus these pH sensitive polyelectrolyte microcapsules may offer a promising delivery system for water soluble proteins and peptides.


Asunto(s)
Sistemas de Liberación de Medicamentos/métodos , Nanocápsulas/química , Polímeros/química , Proteínas/administración & dosificación , Animales , Carbonato de Calcio/química , Bovinos , Supervivencia Celular , Células Cultivadas , Dicroismo Circular , Electrólitos/química , Embrión de Mamíferos/citología , Fibroblastos/citología , Fibroblastos/metabolismo , Metacrilatos/química , Ratones , Microscopía de Fuerza Atómica , Microscopía Confocal , Microscopía Electrónica de Rastreo , Nanocápsulas/ultraestructura , Tamaño de la Partícula , Poliaminas/química , Poliestirenos/química , Proteínas/química , Proteínas/farmacocinética , Albúmina Sérica Bovina/administración & dosificación , Albúmina Sérica Bovina/química , Albúmina Sérica Bovina/farmacocinética , Espectroscopía Infrarroja por Transformada de Fourier
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