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1.
Langmuir ; 39(51): 18971-18982, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38087401

RESUMO

In recent years, there has been a notable increase in the interest toward microfluidic devices for microbubble synthesis. The upsurge can be primarily attributed to the exceptional control these devices offer in terms of both the size and the size distribution of microbubbles. Among various microfluidic devices available, capillary-embedded T-junction microfluidic (CETM) devices have been extensively used for the synthesis of microbubbles. One distinguishing feature of CETM devices from conventional T-junction devices is the existence of a wall at the right-most end, which causes a backflow of the continuous phase at the mixing zone during microbubble formation. The back flow at the mixing zone can have several implications during microbubble formation. It can possibly affect the local velocity and shearing force at the mixing zone, which in turn can affect the size and production rate of the microbubbles. Therefore, in this work, we experimentally and computationally understand the process of microbubble formation in CETM devices. The process is modeled using computational fluid dynamics (CFD) with the volume-of-fluid approach, which solves the Navier-Stokes equations for both the gas and liquid phases. Three scenarios with a constant liquid velocity of 0.053 m/s with varying gas velocity and three with a constant gas velocity of 0.049 m/s at different liquid velocities were explored. Increase in the liquid and gas velocity during microbubble formation was found to enhance production rates in both experiments and simulations. Additionally, the change in microbubble size with the change in liquid velocity was found to agree closely with the findings of the simulation with a coefficient of variation of 10%. When plotted against the time required for microbubble generation, the fluctuations in the pressure showed recurrent crests and troughs throughout the microbubble formation process. The understanding of microbubble formation in CETM devices in the presence of backflow will allow improvement in size reduction of microbubbles.

2.
Langmuir ; 38(17): 5052-5062, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-34264681

RESUMO

Microfluidics is an efficient technique for continuous synthesis of monodispersed microbubbles. However, microbubbles produced using microfluidic devices possess lower stability due to quick dissolution of core gas when exposed to an aqueous environment. This work aims at generating highly stable monodispersed albumin microbubbles using microfluidic T-junction devices. Microbubble generation was facilitated by an aqueous phase consisting of bovine serum albumin (BSA) as a model protein and nitrogen (N2) gas. Microbubbles were chemically cross-linked using dilute glutaraldehyde (0.75% v/v) solution and thermally cross-linked by collecting microbubbles in hot water maintained at 368 (±2) K. These microbubbles were then subjected to in vitro dissolution in an air-saturated water. Microbubbles cross-linked with a combined treatment of thermal and chemical cross-linking (TC & CC) had longer dissolution time compared to microbubbles chemically cross-linked (CC) alone, thermally cross-linked (TC) alone, and non-cross-linked microbubbles. Circular dichroism (CD) spectroscopy analysis revealed that percent reduction in alpha-helices of BSA was higher for the combined treatment of TC & CC when compared to other treatments. In contrast to non-cross-linked microbubbles where microbubble shell dissolved completely, a significant shell detachment was observed during the final phase of the dissolution for cross-linked microbubbles captured using high speed camera, depending upon the extent of cross-linking of the microbubble shell. SEM micrographs of the microbubble shell revealed the shell thickness of microbubbles treated with TC & CC to be highest compared to only thermally or only chemically cross-linked microbubbles. Comparison of microbubble dissolution data to a mass transfer model showed that shell resistance to gas permeation was highest for microbubbles subjected to a combined treatment of TC & CC.


Assuntos
Microbolhas , Microfluídica , Meios de Contraste/química , Dispositivos Lab-On-A-Chip , Soroalbumina Bovina/química , Água
3.
Langmuir ; 38(17): 5040-5051, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-34096296

RESUMO

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease that is increasingly common all over the world with a high risk of progressive hyperglycemia and high microvascular and macrovascular complications. The currently used drugs in the treatment of T2DM have insufficient glucose control and can carry detrimental side effects. Several drug delivery systems have been investigated to decrease the side effects and frequency of dosage, and also to increase the effect of oral antidiabetic drugs. In recent years, the use of microbubbles in biomedical applications has greatly increased, and research into microactive carrier bubbles continues to generate more and more clinical interest. In this study, various monodisperse polymer nanoparticles at different concentrations were produced by bursting microbubbles generated using a T-junction microfluidic device. Morphological analysis by scanning electron microscopy, molecular interactions between the components by FTIR, drug release by UV spectroscopy, and physical analysis such as surface tension and viscosity measurement were carried out for the particles generated and solutions used. The microbubbles and nanoparticles had a smooth outer surface. When the microbubbles/nanoparticles were compared, it was observed that they were optimized with 0.3 wt % poly(vinyl alcohol) (PVA) solution, 40 kPa pressure, and a 110 µL/min flow rate, thus the diameters of the bubbles and particles were 100 ± 10 µm and 70 ± 5 nm, respectively. Metformin was successfully loaded into the nanoparticles in these optimized concentrations and characteristics, and no drug crystals and clusters were seen on the surface. Metformin was released in a controlled manner at pH 1.2 for 60 min and at pH 7.4 for 240 min. The process and structures generated offer great potential for the treatment of T2DM.


Assuntos
Diabetes Mellitus Tipo 2 , Metformina , Nanopartículas , Diabetes Mellitus Tipo 2/tratamento farmacológico , Humanos , Metformina/química , Metformina/uso terapêutico , Microbolhas , Nanopartículas/química , Polímeros
4.
Langmuir ; 38(33): 10288-10304, 2022 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-35943351

RESUMO

Microbubbles are tiny gas-filled bubbles that have a variety of applications in ultrasound imaging and therapeutic drug delivery. Microbubbles can be synthesized using a number of techniques including sonication, amalgamation, and saline shaking. These approaches can produce highly concentrated microbubble suspensions but offer minimal control over the size and polydispersity of the microbubbles. One of the simplest and effective methods for producing monodisperse microbubbles is capillary-embedded T-junction microfluidic devices, which offer great control over the microbubble size. However, lower production rates (∼200 bubbles/s) and large microbubble sizes (∼300 µm) limit the applicability of such devices for biomedical applications. To overcome the limitations of these technologies, we demonstrate in this work an alternative approach to combine a capillary-embedded T-junction device with ultrasound to enhance the generation of narrow-sized microbubbles in aqueous suspensions. Two T-junction microfluidic devices were connected in parallel and combined with an ultrasonic horn to produce lipid-coated SF6 core microbubbles in the size range of 1-8 µm. The rate of microbubble production was found to increase from 180 microbubbles/s in the absence of ultrasound to (6.5 ± 1.2) × 106 bubble/s in the presence of ultrasound (100% ultrasound amplitude). When stored in a closed environment, the microbubbles were observed to be stable for up to 30 days, with the concentration of the microbubble suspension decreasing from ∼2.81 × 109/mL to ∼2.3 × 106/mL and the size changing from 1.73 ± 0.2 to 1.45 ± 0.3 µm at the end of 30 days. The acoustic response of these microbubbles was examined using broadband attenuation spectroscopy, and flow phantom imaging was performed to determine the ability of these microbubble suspensions to enhance the contrast relative to the surrounding tissue. Overall, this approach of coupling ultrasound with microfluidic parallelization enabled the continuous production of stable microbubbles at high production rates and low polydispersity using simple T-junction devices.


Assuntos
Dispositivos Lab-On-A-Chip , Microbolhas , Acústica , Meios de Contraste/química , Suspensões , Ultrassonografia/métodos
5.
Langmuir ; 38(36): 10917-10933, 2022 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-36018789

RESUMO

Long-term stability of microbubbles is crucial to their effectiveness. Using a new microfluidic device connecting three T-junction channels of 100 µm in series, stable monodisperse SiQD-loaded bovine serum albumin (BSA) protein microbubbles down to 22.8 ± 1.4 µm in diameter were generated. Fluorescence microscopy confirmed the integration of SiQD on the microbubble surface, which retained the same morphology as those without SiQD. The microbubble diameter and stability in air were manipulated through appropriate selection of T-junction numbers, capillary diameter, liquid flow rate, and BSA and SiQD concentrations. A predictive computational model was developed from the experimental data, and the number of T-junctions was incorporated into this model as one of the variables. It was illustrated that the diameter of the monodisperse microbubbles generated can be tailored by combining up to three T-junctions in series, while the operating parameters were kept constant. Computational modeling of microbubble diameter and stability agreed with experimental data. The lifetime of microbubbles increased with increasing T-junction number and higher concentrations of BSA and SiQD. The present research sheds light on a potential new route employing SiQD and triple T-junctions to form stable, monodisperse, multi-layered, and well-characterized protein and quantum dot-loaded protein microbubbles with enhanced stability for the first time.


Assuntos
Microbolhas , Pontos Quânticos , Dispositivos Lab-On-A-Chip , Microfluídica , Soroalbumina Bovina , Silício
6.
Langmuir ; 36(39): 11429-11441, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32903006

RESUMO

This work focuses on the synthesis of oil-layered microbubbles using two microfluidic T-junctions in series and evaluation of the effectiveness of these microbubbles loaded with doxorubicin and curcumin for cell invasion arrest from 3D spheroid models of triple negative breast cancer (TNBC), MDA-MB-231 cell line. Albumin microbubbles coated in the drug-laden oil layer were synthesized using a new method of connecting two microfluidic T-mixers in series. Double-layered microbubbles thus produced consist of an innermost core of nitrogen gas encapsulated in an aqueous layer of bovine serum albumin (BSA) which in turn, is coated with an outer layer of silicone oil. In order to identify the process conditions leading to the formation of double-layered microbubbles, a regime map was constructed based on capillary numbers for aqueous and oil phases. The microbubble formation regime transitions from double-layered to single layer microbubbles and then to formation of single oil droplets upon gradual change in flow rates of aqueous and oil phases. In vitro dissolution studies of double-layered microbubbles in an air-saturated environment indicated that a complete dissolution of such bubbles produces an oil droplet devoid of a gas bubble. Incorporation of doxorubicin and curcumin was found to produce a synergistic effect, which resulted in higher cell deaths in 2D monolayers of TNBC cells and inhibition of cell proliferation from 3D spheroid models of TNBC cells compared to the control.


Assuntos
Microbolhas , Microfluídica , Doxorrubicina/farmacologia , Gases , Soroalbumina Bovina
7.
Mol Pharm ; 16(6): 2557-2568, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31021642

RESUMO

Electrospinning is increasingly becoming a viable means of producing drug delivery vehicles for oral delivery, particularly as issues of manufacturing scalability are being addressed. In this study, electrospinning is explored as a taste-masking manufacturing technology for bitter drugs. The taste-masking polymer Eudragit E PO (E-EPO) was electrospun, guided by a quality by design approach. Using a design of experiment, factors influencing the production of smooth fibers were investigated. Polymer concentration, solvent composition, applied voltage, flow rate, and gap distance were the parameters examined. Of these, polymer concentration was shown to be the only statistically significant factor within the ranges studied ( p-value = 0.0042). As the concentration increased, smoother fibers were formed, coupled with an increase in fiber diameter. E-EPO (35% w/v) was identified as the optimum concentration for smooth fiber production. The optimized processing conditions identified were a gap distance of 175 mm, an applied voltage of between 15 and 20 kV, and a flow rate of 1 mL/h. Using this knowledge, the production optimization of electrospun E-EPO with chlorpheniramine maleate (CPM), a bitter antihistamine drug, was explored. The addition of CPM in drug loads of 1:6 up to 1:10 CPM/E-EPO yielded smooth fibers that were electrospun under conditions similar to placebo fibers. Solid-state characterization showed CPM to be molecularly dispersed in E-EPO. An electronic tasting system, or E-tongue, indicated good taste-masking performance as compared to the equivalent physical mixtures. This study therefore describes a means of producing, optimizing, and assessing the performance of electrospun taste-masked fibers as a novel approach to the formulation of CPM and potentially other bitter drug substances.


Assuntos
Clorfeniramina/química , Polímeros/química , Ácidos Polimetacrílicos/química , Varredura Diferencial de Calorimetria , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Viscosidade , Difração de Raios X
8.
Langmuir ; 35(31): 10203-10212, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-30892903

RESUMO

The application of an electric field on a fluid in motion gives rise to unique features and flow manipulation capabilities. Technologies ranging from bubble formation, droplet generation, fiber spinning, and many others are predicated on this type of flows, often referred to as Electrohydrodynamics (EHD). In this paper, we present a numerical methodology that allows for the modeling of such processes in a generalized way. The method can account for the premixing of various liquid species, the injection of gases in the mixture and the interaction of such complex multiphase flow with an electric field, static or AC. The domain in which these processes take place can be of arbitrary geometric complexity, allowing for design and optimization of complex EHD devices. Our study looks at the critical phases of some of these processes and emphasizes the strong coupling of fluid mechanics and electric fields and the influence of the electric field on fluid flow and vice versa. The conservation of mass and momentum, with appropriate additional force terms coming from the presence of the electric field, and the electrostatic equations are coupled together and solved using the Finite Volume method. The Volume of Fluid (VoF) technique is used to track free surfaces dynamically. The solution procedure iteratively computes electric body and surface forces and then includes those into the Navier-Stokes equation to predict the velocity field and other fluid parameters. No initial shape is assumed for the fluid(s) and charge distributions. The methodology presented handles two-dimensional, axisymmetric. and full three-dimensional cases of arbitrary geometric complexity, allowing for mixing and microfluidic configurations of high levels of realism. We highlight the capability of the method by demonstrating cases like the formation of a Taylor cone, microfluidic bubble generation, jet evolution, and droplet breakup. Results agree well with both existing experimental and computational reports.

9.
Langmuir ; 35(31): 10052-10060, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-30995839

RESUMO

In this work, we report a significant advance in the preparation of monodisperse microbubbles using a combination of microfluidic and electric field technologies. Microbubbles have been employed in various fields such as biomedical engineering, water purification, and food engineering. Many techniques have been investigated for their preparation. Of these, the microfluidic T-junction has shown great potential because of the high degree of control it has over processing parameters and the ability to produce monodisperse microbubbles. Two main lines of investigation were conducted in this work-the effect of varying the mixing region distance (Mx) and the influence of altering the tip-to-collector distance (Dx) when an ac-dc field is applied. It was found that when Mx was decreased from 200 to 100 µm, the microbubble diameter also decreased from 128 ± 3 to 88 ± 5 µm due to an increase in shear stress as a result of a reduction in surface area. Similarly, decreasing the tip-to-collector distance results in an increase in the electric field strength experienced at the nozzle, facilitating further reduction of the bubble diameter from 111 ± 1 to 86 ± 1 µm at an ac voltage of 6 kV P-P and an applied dc voltage of 6 kV. Experiments conducted with the optimal parameters identified from these previous experiments enabled further reduction of the microbubble diameter to 18 ± 2 µm. These results suggest that a unique combination of parameters can be employed to achieve particular microbubble diameters to suit various applications.

10.
Int Wound J ; 16(3): 730-736, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30767437

RESUMO

Cinnamon-containing polycaprolactone (PCL) bandages were produced by pressurised gyration and their anti-fungal activities against Candida albicans were investigated. It was found that by preparing and spinning polymer solutions of cinnamon with PCL, fibres capable of inhibiting fungal growth could be produced, as observed in disk diffusion tests for anti-fungal susceptibility. Fascinatingly, compared with raw cinnamon powder, the novel cinnamon-loaded fibres had outstanding long-term activity. The results presented here are very promising and may indeed accelerate a new era of using completely natural materials in biomedical applications, especially in wound healing.


Assuntos
Antifúngicos/química , Bandagens , Candida albicans/efeitos dos fármacos , Cinnamomum zeylanicum/química , Extratos Vegetais/química , Poliésteres/química
11.
Langmuir ; 34(27): 7989-7997, 2018 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-29772899

RESUMO

Amphiphilic block copolymers are widely used in science owing to their versatile properties. In this study, amphiphilic block copolymer poly(lactic- co-glycolic acid)- block-poly(ethylene glycol) (PLGA- b-PEG) was used to create microdroplets in a T-junction microfluidic device with a well-defined geometry. To compare interfacial characteristics of microdroplets, dichloromethane (DCM) and chloroform were used to prepare PLGA- b-PEG solution as an oil phase. In the T-junction device, water and oil phases were manipulated at variable flow rates from 50 to 300 µL/min by increments of 50 µL/min. Fabricated microdroplets were directly collected on a glass slide. After a drying period, porous two-dimensional and three-dimensional structures were obtained as honeycomb-like structure. Pore sizes were increased according to increased water/oil flow rate for both DCM and chloroform solutions. Also, it was shown that increasing polymer concentration decreased the pore size of honeycomb-like structures at a constant water/oil flow rate (50:50 µL/min). Additionally, PLGA- b-PEG nanoparticles were also obtained on the struts of honeycomb-like structures according to the water solubility, volatility, and viscosity properties of oil phases, by the aid of Marangoni flow. The resulting structures have a great potential to be used in biomedical applications, especially in drug delivery-related studies, with nanoparticle forming ability and cellular responses in different surface morphologies.

12.
Nanotechnology ; 29(28): 282001, 2018 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-29620531

RESUMO

The exploration of nanocomposites has gained a strong research following over the last decade. These materials have been heavily exploited in several fields, with applications ranging from biosensors to biomedicine. Among these applications, great advances have been made in the field of microbiology, specifically as antimicrobial agents. This review aims to provide a comprehensive account of various nanocomposites that elucidate promising antimicrobial activity. The composition, physical and chemical properties, as well as the antimicrobial performance of these nanocomposites, are discussed in detail.


Assuntos
Anti-Infecciosos/farmacologia , Nanocompostos/química , Animais , Carbono/farmacologia , Cobre/farmacologia , Humanos , Prata/farmacologia , Titânio/farmacologia
13.
Int Wound J ; 15(5): 789-797, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29806201

RESUMO

Electrospun nanofibrous scaffolds are promising regenerative wound dressing options but have yet to be widely used in practice. The challenge is that nanofibre productions rely on bench-top apparatuses, and the delicate product integrity is hard to preserve before reaching the point of need. Timing is critically important to wound healing. The purpose of this investigation is to produce novel nanofibrous scaffolds using a portable, hand-held "gun", which enables production at the wound site in a time-dependent fashion, thereby preserving product integrity. We select bacterial cellulose, a natural hydrophilic biopolymer, and polycaprolactone, a synthetic hydrophobic polymer, to generate composite nanofibres that can tune the scaffold hydrophilicity, which strongly affects cell proliferation. Composite scaffolds made of 8 different ratios of bacterial cellulose and polycaprolactone were successfully electrospun. The morphological features and cell-scaffold interactions were analysed using scanning electron microscopy. The biocompatibility was studied using Saos-2 cell viability test. The scaffolds were found to show good biocompatibility and allow different proliferation rates that varied with the composition of the scaffolds. A nanofibrous dressing that can be accurately moulded and standardised via the portable technique is advantageous for wound healing in practicality and in its consistency through mass production.


Assuntos
Bandagens , Celulose/uso terapêutico , Nanofibras/uso terapêutico , Poliésteres/uso terapêutico , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos , Alicerces Teciduais , Adulto , Idoso , Idoso de 80 Anos ou mais , Proliferação de Células/fisiologia , Sobrevivência Celular/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cicatrização/fisiologia
14.
Nanotechnology ; 28(5): 052001, 2017 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-28032619

RESUMO

The vaginal route is increasingly being considered for both local and systemic delivery of drugs, especially those unsuitable for oral administration. One of the opportunities offered by this route but yet to be fully utilised is the administration of microbicides. Microbicides have an unprecedented potential for mitigating the global burden from HIV infection as heterosexual contact accounts for most of the new infections occurring in sub-Saharan Africa, the region with the highest prevalent rates. Decades of efforts and massive investment of resources into developing an ideal microbicide have resulted in disappointing outcomes, as attested by several clinical trials assessing the suitability of those formulated so far. The highly complex and multi-level biochemical interactions that must occur among the virus, host cells and the drug for transmission to be halted means that a less sophisticated approach to formulating a microbicide e.g. conventional gels, etc may have to give way for a different formulation approach. Nanotechnology has been identified to offer prospects for fabricating structures with high capability of disrupting HIV transmission. In this review, predominant challenges seen in microbicide development have been highlighted and possible ways of surmounting them suggested. Furthermore, formulations utilising some of these highly promising nanostructures such as liposomes, nanofibres and nanoparticles have been discussed. A perspective on how a tripartite collaboration among governments and their agencies, the pharmaceutical industry and academic scientists to facilitate the development of an ideal microbicide in a timely manner has also been briefly deliberated.


Assuntos
Anti-Infecciosos/farmacocinética , Infecções por HIV/prevenção & controle , Lipossomos/química , Nanofibras/química , Nanopartículas/química , Nanotecnologia/métodos , Administração Intravaginal , Anti-Infecciosos/síntese química , Anti-Infecciosos/uso terapêutico , Dispositivos Anticoncepcionais Femininos , Indústria Farmacêutica/legislação & jurisprudência , Feminino , Órgãos Governamentais/legislação & jurisprudência , Infecções por HIV/virologia , Humanos , Lipossomos/farmacocinética , Nanofibras/administração & dosagem , Nanopartículas/administração & dosagem , Nanotecnologia/instrumentação , Parcerias Público-Privadas/organização & administração , Vagina/efeitos dos fármacos , Vagina/virologia
15.
Ophthalmic Plast Reconstr Surg ; 33(1): 22-26, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-26808175

RESUMO

PURPOSE: To perform quantitative analysis of the most commonly used brow-suspension configurations. METHODS: The inflection positions for Fox pentagon and Crawford triangle configurations were marked on 49 healthy volunteers (male and female) and photographs taken in 3 states: "normal," "closed," and "raised." The skin marks were measured vectorially with respect to the medial canthus, and displacement changes were evaluated for "normal-to-closed" ("blinking") and from "closed-to-raised" ("eye-opening") states. The distance between a pair of inflection marks, representing the approximate path of sling configurations, were also measured and analyzed in relation to the mechanical properties of a variety of synthetic brow-suspension materials. RESULTS: "Blinking" resulted in the greatest displacement in the medial eyelid incision, resulting in the greatest strain on the line connecting the medial eyelid and medial brow inflections. No significant differences in the strains for individual lines were found between the Fox and Crawford techniques, although the former shows a significantly lower overall strain in the whole loop than the latter. The displacements of some inflections and of the strains of a few lines differed significantly in men and women. CONCLUSIONS: Within the scope of this study, the blinking action was shown to result in the maximum strain of ~40%, which lies within the elastic region of stress-strain curves for some commonly used synthetic brow-suspension materials. No one method was statistically superior, although the Fox pentagon gave a significantly lower overall strain when the sling material was assumed to move somewhat around the inflections within a closed loop.


Assuntos
Blefaroptose/cirurgia , Pálpebras/cirurgia , Técnicas de Sutura , Adulto , Idoso , Piscadela/fisiologia , Feminino , Testa/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade
16.
Nanomedicine ; 12(7): 1919-1929, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27184098

RESUMO

Targeted delivery of potent, toxic chemotherapy drugs, such as cisplatin, is a significant area of research in cancer treatment. In this study, cisplatin was successfully encapsulated with high efficiency (>70%) in poly (lactic-co-glycolic acid) polymeric nanoparticles by using electrohydrodynamic atomization (EHDA) where applied voltage and solution flow rate as well as the concentration of cisplatin and polymer were varied to control the size of the particles. Thus, nanoparticles were produced with three different drug:polymer ratios (2.5, 5 and 10wt% cisplatin). It was shown that smaller nanoparticles were produced with 10wt% cisplatin. Furthermore, these demonstrated the best sustained release (smallest burst release). By fitting the experimental data with various kinetic models it was concluded that the release is dependent upon the particle morphology and the drug concentration. Thus, these particles have significant potential for cisplatin delivery with controlled dosage and release period that are crucial chemotherapy parameters.


Assuntos
Antineoplásicos/administração & dosagem , Cisplatino/administração & dosagem , Sistemas de Liberação de Medicamentos , Nanopartículas , Glicóis , Humanos , Ácido Láctico , Tamanho da Partícula , Ácido Poliglicólico
17.
Mol Pharm ; 12(11): 3851-61, 2015 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-26402331

RESUMO

Nanofibrous systems are attracting increasing interest as a means of drug delivery, although a significant limitation to this approach has been manufacture on a scale commensurate with dosage form production. However, recent work has suggested that nanofibers may be successfully manufactured on a suitable scale using the novel process of pressurized gyration (PG). In this study, we explore the potential of PG as a novel means of generating amorphous solid dispersions of poorly water-soluble drugs with enhanced dissolution performance. We examine the effect of increasing drug loading on fiber properties including size, surface characteristics, and the physical state of both components. Dispersions of ibuprofen in poly(vinylpyrrolidone) (PVP) were prepared (up to 50% w/w loading) and characterized using a range of imaging, thermal, diffraction, and spectroscopic techniques, while the release profiles were studied using sink and non-sink (pH 1.0) conditions. The drug was found to be dispersed on a molecular basis within the fibers; attenuated total reflection FTIR indicated evidence for a direct interaction between the drug and polymer at lower drug loading by the identification of a strong single band in the carbonyl region and amide region of ibuprofen and PVP respectively. Dissolution studies under sink conditions indicated a substantial increase in release rate, while non-sink studies showed evidence for supersaturation. It is concluded that PG presents a viable method for the production of drug-loaded nanofibers for oral administration with enhanced in vitro dissolution rate enhancement.


Assuntos
Portadores de Fármacos/química , Excipientes/química , Ibuprofeno/química , Nanofibras/química , Polímeros/química , Varredura Diferencial de Calorimetria , Química Farmacêutica , Estabilidade de Medicamentos , Ibuprofeno/administração & dosagem , Pressão , Solubilidade , Água/química , Difração de Raios X
18.
Langmuir ; 31(36): 9771-80, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26307462

RESUMO

In this work, the biosensing and antibacterial capabilities of PVA-lysozyme microbubbles have been explored. Gas-filled PVA-lysozyme microbubbles with and without gold nanoparticles in the diameter range of 10 to 250 µm were produced using a single-step pressurized gyration process. Fluorescence microscopy showed the integration of gold nanoparticles on the shell of the microbubbles. Microbubbles prepared with gold nanoparticles showed greater optical extinction values than those without gold nanoparticles, and these values increased with the concentration of the gold nanoparticles. Both types of microbubbles showed antibacterial activity against Gram-negative Escherichia coli (E. coli), with the bubbles containing the gold nanoparticles performing better than the former. The conjugation of the microbubbles with alkaline phosphatase allowed the detection of pesticide paraoxon in aqueous solution, and this demonstrates the biosensing capabilities of these microbubbles.


Assuntos
Antibacterianos/farmacologia , Técnicas Biossensoriais , Muramidase/química , Álcool de Polivinil/química , Pressão
19.
Langmuir ; 31(2): 659-66, 2015 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-25027827

RESUMO

A one-pot single-step novel process has been developed to form microbubbles up to 250 µm in diameter using a pressurized rotating device. The microbubble diameter is shown to be a function of rotational speed and working pressure of the processing system, and a modified Rayleigh-Plesset equation has been derived to explain the bubble-forming mechanism. A parametric plot is constructed to identify a rotating speed and working pressure regime, which allows for continuous bubbling. Bare protein (lysozyme) microbubbles generated in this way exhibit a morphological change, resulting in microcapsules over a period of time. Microbubbles prepared with gold nanoparticles at the bubble surface showed greater stability over a time period and retained the same morphology. The functionalization of microbubbles with gold nanoparticles also rendered optical tunability and has promising applications in imaging, biosensing, and diagnostics.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Microbolhas
20.
Macromol Rapid Commun ; 36(14): 1322-8, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26033345

RESUMO

Nanofibers featuring functional nanoassemblies show great promise as enabling constituents for a diverse range of applications in areas such as tissue engineering, sensing, optoelectronics, and nanophotonics due to their controlled organization and architecture. An infusion gyration method is reported that enables the production of nanofibers with inherent biological functions by simply adjusting the flow rate of a polymer solution. Sufficient polymer chain entanglement is obtained at Berry number > 1.6 to make bead-free fibers integrated with gold nanoparticles and proteins, in the diameter range of 117-216 nm. Integration of gold nanoparticles into the nanofiber assembly is followed using a gold-binding peptide tag genetically conjugated to red fluorescence protein (DsRed). Fluorescence microscopy analysis corroborated with Fourier transform infrared spectroscopy (FTIR) data confirms the integration of the engineered red fluorescence protein with the nanofibers. The gold nanoparticle decorated nanofibers having red fluorescence protein as an integral part keep their biological functionality including copper-induced fluorescence quenching of the DsRed protein due to its selective Cu(+2) binding. Thus, coupling the infusion gyration method in this way offers a simple nanoscale assembly approach to integrate a diverse repertoire of protein functionalities into nanofibers to generate biohybrid materials for imaging, sensing, and biomaterial applications.


Assuntos
Nanofibras/química , Polímeros/química , Proteínas/metabolismo , Materiais Biocompatíveis/química , Eletrônica , Ouro/química , Microscopia de Fluorescência , Proteínas/química , Proteínas/genética , Espectroscopia de Infravermelho com Transformada de Fourier , Ressonância de Plasmônio de Superfície , Engenharia Tecidual
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