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1.
Cells Tissues Organs ; : 1-14, 2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33596574

RESUMO

Research on synthesis, characterization, and understanding of novel properties of nanomaterials has led researchers to exploit their potential applications. When compared to other nanotechnologies described in the literature, electrospinning has received significant interest due to its ability to synthesize novel nanostructures (such as nanofibers, nanorods, nanotubes, etc.) with distinctive properties such as high surface-to-volume ratio, porosity, various morphologies such as fibers, tubes, ribbons, mesoporous and coated structures, and so on. Various materials such as polymers, ceramics, and composites have been fabricated using the electrospinning technique. Among them, polymers, especially block copolymers, are one of the useful and niche systems studied recently owing to their unique and fascinating properties in both solution and solid state due to thermodynamic incompatibility of the blocks, that results in microphase separation. Morphology and mechanical properties of electrospun block copolymers are intensely influenced by quantity and length of soft and hard segments. They are one of the best studied systems to fit numerous applications due to a broad variety of properties they display upon varying the composition ratio and molecular weight of blocks. In this review, the synthesis, fundamentals, electrospinning, and tissue engineering application of block copolymers are highlighted.

2.
J Colloid Interface Sci ; 585: 237-249, 2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33285462

RESUMO

HYPOTHESIS: Organic radical polymers with tailored pendant functionalities have emerged as exciting and promising materials for their application versatility. Moreover, eco-friendly polymer-based organic nanomaterials with redox-active pendant side groups can replace the harmful heavy metal-based inorganic materials. On the other hand, self-assembled nanomaterials are of great interest and attracted more attention recently for their promising application in different advanced fields, but it is yet challenging to predict suitable hydrophilic-lipophilic balance (HLB) for stimuli-responsive random copolymers assembly due to structural irregularity. Among several experimental techniques, electron paramagnetic resonance (EPR) spectroscopy plays a unique and promising role in revealing structural and dynamic information of nanostructured radical containing materials. EXPERIMENTS: In this study, a series of spin labeled amphiphilic random copolymers poly(methyl methacrylate-co-acrylic acid) have been synthesized and characterized by FT-IR, UV-Vis spectroscopies, TGA, DSC and water contact angle (CA) techniques. Their electrochemical properties have been determined by cyclic voltammetry (CV) in different organic solvents. EPR spectroscopy has been applied with other analytical techniques to elucidate the smart supramolecular nanoparticles (SNPs) formation, stimuli-responsiveness and structural changes through the dynamics of different molecular interactions. FINDINGS: The structural and dynamic information of self-assembled nanoparticles have been observed to be dependent on multiple-stimuli-responsiveness in different microenvironments by applying physiological and chemical parameters such as the different concentration of radicals, pH, temperature, nature of the solvent and reducing agent. The obtained results reveal the knowledge to understand insight into the mechanism for the formation of stimuli-responsive colloidal nanoparticles assembled from amphiphilic random copolymers with apt HLB value. The CV results reveal that the charge transfer process of the nanoparticles in solution was diffusion regulated and depended on the accessibility of radicals. The radical (spin labeled) polymers offer a broad way to develop stimuli-responsive materials in various colloidal nanostructures by changing the microenvironment, appreciating their potential advanced applications in electronic devices, catalysis, stimuli-triggered drug/gene delivery and reactive oxygen species (ROS) scavenger.

3.
Sci Rep ; 10(1): 19751, 2020 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-33184317

RESUMO

Textile-based Scaffolds preparation has the attractive features to fulfill the stated and implied needs of the consumer but there are still challenges of stability, elongation, appreciable bio-compatibility, and stated hydrophilic behavior. To overcome these challenges, the authors tried to fabricate a scaffold by blending of two highly biocompatible polymers; polyvinyl alcohol and poly(1,4 cyclohexane isosorbide terephthalate) through co-electrospinning. The resultant scaffold by the stated innovative approach evaluated from different characterizations such as dimensional stability/morphology was evaluated by scanning electron microscopy, chemical interactions by that Fourier transmission infrared spectra, wetting behavior was analyzed by a static angle with a contact angle meter from drop method, elongation was examined by tensile strength tester and in-vitro assessment was done by MTT analysis. Based on verified results, it was concluded that PVA/PICT scaffold has a potential for dual nature of hydrophilicity & hydrophobicity and appreciable cell culture growth, stated dimensional stability and suitable elongation as per requirements of the nature of scaffold.

4.
Phys Rev Lett ; 125(14): 143603, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33064534

RESUMO

The possibility of a superradiant phase transition in light-matter systems is the subject of much debate, due to numerous apparently conflicting no-go and counter no-go theorems. Using an arbitrary-gauge approach we show that a unique phase transition does occur in archetypal many-dipole cavity QED systems, and that it manifests unambiguously via a macroscopic gauge-invariant polarization. We find that the gauge choice controls the extent to which this polarization is included as part of the radiative quantum subsystem and thereby determines the degree to which the abnormal phase is classed as superradiant. This resolves the long-standing paradox of no-go and counter no-go theorems for superradiance, which are shown to refer to different definitions of radiation.

5.
Phys Rev Lett ; 125(4): 043603, 2020 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-32794814

RESUMO

Spectral filtering of resonance fluorescence is widely employed to improve single photon purity and indistinguishability by removing unwanted backgrounds. For filter bandwidths approaching the emitter linewidth, complex behavior is predicted due to preferential transmission of components with differing photon statistics. We probe this regime using a Purcell-enhanced quantum dot in both weak and strong excitation limits, finding excellent agreement with an extended sensor theory model. By changing only the filter width, the photon statistics can be transformed between antibunched, bunched, or Poissonian. Our results verify that strong antibunching and a subnatural linewidth cannot simultaneously be observed, providing new insight into the nature of coherent scattering.

6.
Phys Rev E ; 101(5-1): 052129, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32575334

RESUMO

We show that finite system-reservoir coupling imposes a distinct quantum limit on the performance of a nonequilibrium quantum heat engine. Even in the absence of quantum friction along the isentropic strokes, finite system-reservoir coupling induces correlations that result in the generation of coherence between the energy eigenstates of the working system. This coherence acts to hamper the engine's power output, as well as the efficiency with which it can convert heat into useful work, and cannot be captured by a standard Born-Markov analysis of the system-reservoir interactions.

7.
Phys Rev Lett ; 123(16): 167403, 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31702333

RESUMO

Coherent scattering of light by a single quantum emitter is a fundamental process at the heart of many proposed quantum technologies. Unlike atomic systems, solid-state emitters couple to their host lattice by phonons. Using a quantum dot in an optical nanocavity, we resolve these interactions in both time and frequency domains, going beyond the atomic picture to develop a comprehensive model of light scattering from solid-state emitters. We find that even in the presence of a low-Q cavity with high Purcell enhancement, phonon coupling leads to a sideband that is completely insensitive to excitation conditions and to a nonmonotonic relationship between laser detuning and coherent fraction, both of which are major deviations from atomlike behavior.

8.
Phys Rev Lett ; 123(9): 093601, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31524488

RESUMO

We show that for a quantum system coupled to both vibrational and electromagnetic environments, enforcing additivity of their combined influences results in nonequilibrium dynamics that does not respect the Franck-Condon principle. We overcome this shortcoming by employing a collective coordinate representation of the vibrational environment, which permits the derivation of a nonadditive master equation. When applied to a two-level emitter our treatment predicts decreasing photon emission rates with increasing vibrational coupling, consistent with Franck-Condon physics. In contrast, the additive approximation predicts the emission rate to be completely insensitive to vibrations. We find that nonadditivity also plays a key role in the stationary nonequilibrium model behavior, enabling two-level population inversion under incoherent electromagnetic excitation.

9.
Nat Commun ; 10(1): 3034, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31292447

RESUMO

Vibrational environments are commonly considered to be detrimental to the optical emission properties of solid-state and molecular systems, limiting their performance within quantum information protocols. Given that such environments arise naturally it is important to ask whether they can instead be turned to our advantage. Here we show that vibrational interactions can be harnessed within resonance fluorescence to generate optical states with a higher degree of quadrature squeezing than in isolated atomic systems. Considering the example of a driven quantum dot coupled to phonons, we demonstrate that it is feasible to surpass the maximum level of squeezing theoretically obtainable in an isolated atomic system and indeed come close to saturating the fundamental upper bound on squeezing from a two-level emitter. We analyse the performance of these vibrationally-enhanced squeezed states in a phase estimation protocol, finding that for the same photon flux, they can outperform the single mode squeezed vacuum state.

10.
Int J Biol Macromol ; 135: 1222-1236, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31173830

RESUMO

Chitosan (CS) is a well-known biological macromolecule having numerous applications due to its exceptional properties especially in the form of nanofibers. The antibacterial activity is compromised when co-polymers are added to electrospun CS but, the reproducibility can be enhanced which is key to commercialization. We have tried to enhance the antibacterial activity of chitosan based nanofibers with the addition of Zinc oxide (ZO) nanoparticles and ciprofloxacin (model drug) at very low concentrations. The rheology of solutions was studied along with the process parameters for the optimization of nanofibers using response surface methodology. Nanofibers having diameter of 116 nm with a SD of only 21 nm were optimized. ZO loaded nanofibers showed better thermal stability. Different drug release models were fitted to drug release profile. The release was pH dependent best followed by Zero order and Hixson Crowell release models. Good antibacterial activity and non-toxicity was observed against human dermal fibroblast and keratinocytes cell lines (>82.5%) which justifies its potential to eliminate or prevent infection in burn wounds with less side effects due to low amount of drug.


Assuntos
Antibacterianos/farmacologia , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/etiologia , Queimaduras/complicações , Quitosana/química , Nanofibras/química , Polietilenoglicóis/química , Antibacterianos/química , Gerenciamento Clínico , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Humanos , Nanofibras/ultraestrutura , Análise Espectral , Termogravimetria
11.
Carbohydr Res ; 476: 12-35, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30884443

RESUMO

Starch is a homopolysaccharide made up of glucose units which are linked together via a glycosidic linkage. This biopolymer is well known for its low cost, biodegradability, renewability and easy availability. In spite of all these beauties, starch has some problems with their solubility in water, retrogradation, loss of viscosity due to rupturing of glucosidic bond when subjected to treatment and absence of some groups of primary importance like different functional groups especially carboxylic group, ester group, ether group and amino group. In order to overcome these shortcomings and enhance its applications, starch must be modified. The modification can be done chemically, physically and enzymatically, but noteworthy one is the chemical modification. In this review article, we focused on the recently used ways of chemical modification such as acid hydrolysis, cross-linking, acetylation/esterification, dual modification, oxidation and grafting of starch, and their properties. This review article highlighted the application of modified starch as an adsorbent for the removal of ammonia, phenol, heavy metals, and dyes.


Assuntos
Amido/química , Adsorção , Hidrólise , Solubilidade
12.
Nat Commun ; 10(1): 499, 2019 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-30700701

RESUMO

Ultrastrong-coupling between two-level systems and radiation is important for both fundamental and applied quantum electrodynamics (QED). Such regimes are identified by the breakdown of the rotating-wave approximation, which applied to the quantum Rabi model (QRM) yields the apparently less fundamental Jaynes-Cummings model (JCM). We show that when truncating the material system to two levels, each gauge gives a different description whose predictions vary significantly for ultrastrong-coupling. QRMs are obtained through specific gauge choices, but so too is a JCM without needing the rotating-wave approximation. Analysing a circuit QED setup, we find that this JCM provides more accurate predictions than the QRM for the ground state, and often for the first excited state as well. Thus, Jaynes-Cummings physics is not restricted to light-matter coupling below the ultrastrong limit. Among the many implications is that the system's ground state is not necessarily highly entangled, which is usually considered a hallmark of ultrastrong-coupling.

13.
Mater Sci Eng C Mater Biol Appl ; 97: 966-977, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30678985

RESUMO

Cancer is one of the most dangerous diseases which had been encountering the human beings since last several decades. In 2018, according to national cancer institute, about 609,640 people are expected to die from cancer and about 1,735,350 new patients are expected to be diagnosed with this lethal disease. Nanotechnology has played a significant role in almost every field of life including medical sciences. A controlled and sustained release of drug is much desirable and beneficial when one has to deal with cancer as such drugs do also harm to normal cells. General anticancer drugs, used in chemotherapy, are associated with severe side effects due to high dosage requirements. With the help of nanotechnology, great outcomes for instance, anticancer drug loaded nanofibers, have been achieved in cancer therapy requiring less amount of drug as drug is preserved in these nanofibers for prolonged time. Electrospun nanofibers have very large surface area, controllable pore size and tunable drug release profiles which make these nanofibers promising candidates in medical field. To promote green synthesis of nanofibers, researchers have also used water as an effective solvent instead of toxic chemicals and reduced the environmental burden. This green approach of nanofibers fabrication has a good potential to be used in regenerative medicine including cancer therapy because of environmental friendly characteristics. Though, there are numerous research reports available on the application of nanofibers. To the best of our knowledge, no review paper has been reported solely on the applications of nanofibers for cancer therapy. Therefore, this review paper describes some electrospun nanofibers of pure polymer, blends and block copolymers that have been reported for successful cancer therapy.


Assuntos
Antineoplásicos/uso terapêutico , Nanofibras/química , Neoplasias/tratamento farmacológico , Polímeros/química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Humanos , Nanofibras/toxicidade , Neoplasias/patologia , Peptídeos/química
14.
Photodermatol Photoimmunol Photomed ; 35(2): 93-99, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30251290

RESUMO

Harmful effects of ultraviolet rays and protection against them have been long discussed. Numerous synthetic dyes, finishes, UV absorbers, and optical brightening agents are present in the market for decades for achieving UV protection through textiles. However, due to environmental impacts of these chemical agents, textile industry is looking for alternatives. In this regard, some natural dyes and plant extracts have shown promising results. However, use of colorless plant extracts as UV protective finishes is still rare. In this study, ultraviolet protection factor (UPF) rating of bleached cotton fabric has been improved by the application of plant extracts with minimal change in fabric's color. For this purpose, two medicinal plants, that is, Solanum nigrum and Amaranthus viridis were selected and bleached cotton fabric was treated with their methanolic and aqueous extracts. Fabrics treated with both extracts exhibited excellent UPF ratings.


Assuntos
Amaranthus/química , Metanol/química , Extratos Vegetais/química , Solanum nigrum/química , Protetores Solares/química , Têxteis , Humanos , Queimadura Solar/prevenção & controle
15.
Int J Biol Macromol ; 120(Pt B): 2418-2430, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30195611

RESUMO

Development of curcumin-loaded mixed polymeric micelles based on chitosan, alginate, maltodextrin, pluronic F127, pluronic P123, and tween 80, by thin-film hydration method has been investigated in Bisphenol A induced diabetics rats. Curcumin (C21H20O6) extracted from rhizomes of the "Curcuma longa" has attracted considerable attention of pharmaceutical researchers due to its low cost, excellent pharmacological activities and lesser side effects. Despite its diverse pharmacological properties, the therapeutic application of curcumin as an oral therapy has been limited due to its poor aqueous solubility, fixed chemical stability, and low bioavailability. In an attempt to overcome these limitations, we developed curcumin-loaded mixed polymeric micelles. Diabetes mellitus is a most common chronic carbohydrate metabolic disorder. The results clearly demonstrated the ability of developed formulation to reduce the elevated blood glucose level and lipid profile (total cholesterol, triglycerides). It maintained the body-weight, HDL cholesterol level, various biochemical parameters and accelerated the wound healing process when treated with these curcumin-based formulations. The treatment of curcumin loaded mixed polymeric formulations allowed a favorable inhibitory effect to these histopathological changes of liver, kidney, and pancreas. The newly developed curcumin-based formulations have proved superior therapeutic potential and excellent healing efficacy as compared to standard drugs and pure curcumin.


Assuntos
Alginatos/química , Quitosana/química , Curcumina/química , Poloxaleno/química , Poloxâmero/química , Polissacarídeos/química , Cicatrização/efeitos dos fármacos , Animais , Disponibilidade Biológica , Glicemia/metabolismo , Curcumina/farmacocinética , Curcumina/farmacologia , Curcumina/uso terapêutico , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/patologia , Portadores de Fármacos/química , Hipoglicemiantes/química , Hipoglicemiantes/farmacocinética , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/patologia , Micelas , Polissorbatos/química , Ratos
16.
AAPS PharmSciTech ; 19(6): 2719-2739, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29978290

RESUMO

Curcumin is a naturally occurring constituent of turmeric that is a good substitute for synthetic medicines for the treatment of different diseases, due to its comparatively safer profile. However, there are certain shortcomings that limit its use as an ideal therapeutic agent. In order to overcome these drawbacks, we prepared novel curcumin-loaded mixed polymeric micelles using different biocompatible polymers by the thin-film hydration method. We investigated the critical micelle concentration and temperature, drug loading and encapsulation efficiency, and minimum inhibitory concentration by spectrophotometry. Surface morphology, stability, particle size, drug-polymer interaction, and physical state of the prepared formulations were investigated using scanning electron microscopy, zeta potential, particle size analyzer, Fourier-transform infrared spectroscopy, and X-ray diffraction, respectively. The drug loading and entrapment efficiency were significantly increased (P < 0.01) when curcumin was encapsulated with pluronic-based mixed polymeric micelles as compared to that of pluronic-based micelles alone. In vitro studies exhibited that pluronic-based mixed polymeric micelles significantly increased anticancer (P < 0.01), antimicrobial (P < 0.001), antioxidant (P < 0.001), and α-amylase inhibitory (P < 0.001) activities when compared to pure curcumin and/or pluronic-based micelles alone. These findings suggest that the formation of mixed polymeric micelles increases the stability and solubility of curcumin.


Assuntos
Curcumina/química , Portadores de Fármacos/química , Micelas , Poloxâmero/química , Polímeros/química , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/metabolismo , Antineoplásicos/administração & dosagem , Antineoplásicos/química , Antineoplásicos/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Curcumina/administração & dosagem , Curcumina/metabolismo , Relação Dose-Resposta a Droga , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/metabolismo , Excipientes/administração & dosagem , Excipientes/química , Excipientes/metabolismo , Células HeLa , Humanos , Tamanho da Partícula , Poloxâmero/administração & dosagem , Poloxâmero/metabolismo , Polímeros/administração & dosagem , Polímeros/metabolismo , Solubilidade , Difração de Raios X/métodos
17.
J Mater Chem B ; 6(23): 3831-3854, 2018 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32254311

RESUMO

In past few years, phenylboronic acids (PBAs) have attracted researcher's attention due to their unique responsiveness towards diol-containing molecules such as glucose. This property allows hydrogel-bearing PBAs potentially to serve as an alternative for glucose-sensing and insulin-delivery systems. This review provides an outlook on the binding mechanism of PBA moieties with diols and the approaches to increase their binding selectivity and response for glucose molecules. The preparation methods and strategies of hydrogel-bearing PBA moieties along with their properties are discussed. In the last section, their applications in glucose-sensing and insulin-regulatory systems are described.

18.
Phys Rev E ; 95(3-1): 032139, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28415330

RESUMO

We study a quantum heat engine at strong coupling between the system and the thermal reservoirs. Exploiting a collective coordinate mapping, we incorporate system-reservoir correlations into a consistent thermodynamic analysis, thus circumventing the usual restriction to weak coupling and vanishing correlations. We apply our formalism to the example of a quantum Otto cycle, demonstrating that the performance of the engine is diminished in the strong coupling regime with respect to its weakly coupled counterpart, producing a reduced net work output and operating at a lower energy conversion efficiency. We identify costs imposed by sudden decoupling of the system and reservoirs around the cycle as being primarily responsible for the diminished performance, and we define an alternative operational procedure which can partially recover the work output and efficiency. More generally, the collective coordinate mapping holds considerable promise for wider studies of thermodynamic systems beyond weak reservoir coupling.

19.
J Chem Phys ; 144(4): 044110, 2016 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-26827205

RESUMO

We explore excitonic energy transfer dynamics in a molecular dimer system coupled to both structured and unstructured oscillator environments. By extending the reaction coordinate master equation technique developed by Iles-Smith et al. [Phys. Rev. A 90, 032114 (2014)], we go beyond the commonly used Born-Markov approximations to incorporate system-environment correlations and the resultant non-Markovian dynamical effects. We obtain energy transfer dynamics for both underdamped and overdamped oscillator environments that are in perfect agreement with the numerical hierarchical equations of motion over a wide range of parameters. Furthermore, we show that the Zusman equations, which may be obtained in a semiclassical limit of the reaction coordinate model, are often incapable of describing the correct dynamical behaviour. This demonstrates the necessity of properly accounting for quantum correlations generated between the system and its environment when the Born-Markov approximations no longer hold. Finally, we apply the reaction coordinate formalism to the case of a structured environment comprising of both underdamped (i.e., sharply peaked) and overdamped (broad) components simultaneously. We find that though an enhancement of the dimer energy transfer rate can be obtained when compared to an unstructured environment, its magnitude is rather sensitive to both the dimer-peak resonance conditions and the relative strengths of the underdamped and overdamped contributions.

20.
J Phys Condens Matter ; 28(10): 103002, 2016 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-26882465

RESUMO

We provide a self-contained review of master equation approaches to modelling phonon effects in optically driven self-assembled quantum dots. Coupling of the (quasi) two-level excitonic system to phonons leads to dissipation and dephasing, the rates of which depend on the excitation conditions, intrinsic properties of the QD sample, and its temperature. We describe several techniques, which include weak-coupling master equations that are perturbative in the exciton-phonon coupling, as well as those based on the polaron transformation that can remain valid for strong phonon interactions. We additionally consider the role of phonons in altering the optical emission characteristics of quantum dot devices, outlining how we must modify standard quantum optics treatments to account for the presence of the solid-state environment.

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