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1.
Adv Mater ; 32(40): e2004147, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32864764

RESUMO

Artificial microcilia structures have shown potential to incorporate actuators in various applications such as microfluidic devices and biomimetic microrobots. Among the multiple possibilities to achieve cilia actuation, magnetic fields present an opportunity given their quick response and wireless operation, despite the difficulty in achieving localized actuation because of their continuous distribution. In this work, a high-aspect-ratio (>8), elastomeric, magnetically responsive microcilia array is presented that allows for wireless, localized actuation through the combined use of light and magnetic fields. The microcilia array can move in response to an external magnetic field and can be locally actuated by targeted illumination of specific areas. The periodic pattern of the microcilia also diffracts light with varying diffraction efficiency as a function of the applied magnetic field, showing potential for wirelessly controlled adaptive optical elements.

2.
Proc Natl Acad Sci U S A ; 117(25): 14602-14608, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32522869

RESUMO

Bioinspired actuators with stimuli-responsive and deformable properties are being pursued in fields such as artificial tissues, medical devices and diagnostics, and intelligent biosensors. These applications require that actuator systems have biocompatibility, controlled deformability, biodegradability, mechanical durability, and stable reversibility. Herein, we report a bionic actuator system consisting of stimuli-responsive genetically engineered silk-elastin-like protein (SELP) hydrogels and wood-derived cellulose nanofibers (CNFs), which respond to temperature and ionic strength underwater by ecofriendly methods. Programmed site-selective actuation can be predicted and folded into three-dimensional (3D) origami-like shapes. The reversible deformation performance of the SELP/CNF actuators was quantified, and complex spatial transformations of multilayer actuators were demonstrated, including a biomimetic flower design with selective petal movements. Such actuators consisting entirely of biocompatible and biodegradable materials will offer an option toward constructing stimuli-responsive systems for in vivo biomedicine soft robotics and bionic research.


Assuntos
Materiais Biocompatíveis/química , Materiais Biomiméticos/química , Biônica/métodos , Celulose/química , Elastina/química , Elastina/genética , Hidrogéis/química , Conformação Molecular , Nanofibras/química , Engenharia de Proteínas , Robótica/métodos , Seda/química , Seda/genética
3.
Artigo em Inglês | MEDLINE | ID: mdl-32462737

RESUMO

Wearable interfaces are central to multiple healthcare and wellness strategies encompassing diet and nutrition, personalized health monitoring, and performance optimization. Specifically, the advent of flexible electronic formats coupled with microfluidic interfaces has resulted in sophisticated conformal devices for biofluid sampling and quantification. Here, a complementary approach is presented to wearable sensing by using a large-scale, conformal, distributed format that relies on the use of biomaterial-based inks to print and stabilize deterministic patterns of biochemical reporters with high resolution. Colorimetric devices can vary in size and a sensing T-shirt based on a colorimetric pattern is developed to illustrate the utility that such formats can add to the wearable interface space. Image analysis allows parameter variation to be tracked in real-time, yielding a map-like format of distributed biophysical response.

4.
Macromol Biosci ; 20(1): e1900191, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31433126

RESUMO

Hierarchical molecular assembly is a fundamental strategy for manufacturing protein structures in nature. However, to translate this natural strategy into advanced digital manufacturing like three-dimensional (3D) printing remains a technical challenge. This work presents a 3D printing technique with silk fibroin to address this challenge, by rationally designing an aqueous salt bath capable of directing the hierarchical assembly of the protein molecules. This technique, conducted under aqueous and ambient conditions, results in 3D proteinaceous architectures characterized by intrinsic biocompatibility/biodegradability and robust mechanical features. The versatility of this method is shown in a diversity of 3D shapes and a range of functional components integrated into the 3D prints. The manufacturing capability is exemplified by the single-step construction of perfusable microfluidic chips which eliminates the use of supporting or sacrificial materials. The 3D shaping capability of the protein material can benefit a multitude of biomedical devices, from drug delivery to surgical implants to tissue scaffolds. This work also provides insights into the recapitulation of solvent-directed hierarchical molecular assembly for artificial manufacturing.

5.
Proc Natl Acad Sci U S A ; 116(43): 21361-21368, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31591247

RESUMO

Protein micro/nanopatterning has long provided sophisticated strategies for a wide range of applications including biointerfaces, tissue engineering, optics/photonics, and bioelectronics. We present here the use of regenerated silk fibroin to explore wrinkle formation by exploiting the structure-function relation of silk. This yields a biopolymer-based reversible, multiresponsive, dynamic wrinkling system based on the protein's responsiveness to external stimuli that allows on-demand tuning of surface morphologies and properties. The polymorphic transitions of silk fibroin enable modulation of the wrinkle patterns and, consequently, the material's physical properties. The interplay between silk protein chains and external stimuli enables control over the protein film's wrinkling dynamics. Thanks to the versatility of regenerated silk fibroin as a technological substrate, a number of demonstrator devices of varying utility are shown ranging from information encoding to modulation of optical transparency and thermal regulation.


Assuntos
Fibroínas/química , Seda/química , Animais , Materiais Biocompatíveis/química , Bombyx , Teste de Materiais , Engenharia Tecidual/instrumentação
6.
Adv Mater ; 31(36): e1901036, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31309624

RESUMO

Patterning of photonic crystals to generate rationally designed color-responsive materials has drawn considerable interest because of promising applications in optical storage, encryption, display, and sensing. Here, an inkjet-printing based strategy is presented for noncontact, rapid, and direct approaches to generate arbitrarily patterned photonic crystals. The strategy is based on the use of water-soluble biopolymer-based opal structures that can be reformed with high resolution through precise deposition of fluids on the photonic crystal lattice. The resulting digitally designed photonic lattice formats simultaneously exploit structural color and material transience opening avenues for information encoding and combining functions of optics, biomaterials, and environmental interfaces in a single device.


Assuntos
Materiais Biocompatíveis/química , Tinta , Nanoestruturas/química , Fótons , Impressão , Biopolímeros/química , Solubilidade , Água/química
8.
Nano Lett ; 19(4): 2620-2626, 2019 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-30908917

RESUMO

Nanoscale field-effect transistors (FETs) represent a unique platform for real time, label-free transduction of biochemical signals with unprecedented sensitivity and spatiotemporal resolution, yet their translation toward practical biomedical applications remains challenging. Herein, we demonstrate the potential to overcome several key limitations of traditional FET sensors by exploiting bioactive hydrogels as the gate material. Spatially defined photopolymerization is utilized to achieve selective patterning of polyethylene glycol on top of individual graphene FET devices, through which multiple biospecific receptors can be independently encapsulated into the hydrogel gate. The hydrogel-mediated integration of penicillinase was demonstrated to effectively catalyze enzymatic reaction in the confined microenvironment, enabling real time, label-free detection of penicillin down to 0.2 mM. Multiplexed functionalization with penicillinase and acetylcholinesterase has been demonstrated to achieve highly specific sensing. In addition, the microenvironment created by the hydrogel gate has been shown to significantly reduce the nonspecific binding of nontarget molecules to graphene channels as well as preserve the encapsulated enzyme activity for at least one week, in comparison to free enzymes showing significant signal loss within one day. This general approach presents a new biointegration strategy and facilitates multiplex detection of bioanalytes on the same platform, which could underwrite new advances in healthcare research.


Assuntos
Técnicas Biossensoriais/métodos , Nanotecnologia/métodos , Penicilinase/química , Penicilinas/isolamento & purificação , Pesquisa Biomédica/tendências , Grafite/química , Humanos , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Penicilinas/química , Polietilenoglicóis/química , Transistores Eletrônicos
9.
Adv Mater ; 31(5): e1805312, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30520166

RESUMO

Naturally occurring iridescent systems produce brilliant color displays through multiscale, hierarchical assembly of structures that combine reflective, diffractive, diffusive, or absorbing domains. The fabrication of biopolymer-based, hierarchical 3D photonic crystals through the use of a topographical templating strategy that allows combined optical effects derived from the interplay of predesigned 2D and 3D geometries is reported here. This biomaterials-based approach generates 2D diffractive optics composed of 3D nanophotonic lattices that allow simultaneous control over the reflection (through the 3D photonic bandgap) and the transmission (through 2D diffractive structuring) of light with the additional utility of being constituted by a biocompatible, implantable, edible commodity textile material. The use of biopolymers allows additional degrees of freedom in photonic bandgap design through directed protein conformation modulation. Demonstrator structures are presented to illustrate the lattice multifunctionality, including tunable diffractive properties, increased angle of view of photonic crystals, color-mixing, and sensing applications.

10.
Adv Sci (Weinh) ; 5(7): 1700982, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30027034

RESUMO

Recent progress in ultrafast spectroscopy and semiconductor technology is enabling unique applications in screening, detection, and diagnostics in the Terahertz (T-ray) regime. The promise of efficaciously operation in this spectral region is tempered by the lack of devices that can spectrally analyze samples at sufficient temporal and spatial resolution. Real-time, multispectral T-ray (Mul-T) imaging is reported by designing and demonstrating hyperspectral metamaterial focal plane array (MM-FPA) interfaces allowing multiband (and individually tunable) responses without compromising on the pixel size. These MM-FPAs are fully compatible with existing microfabrication technologies and have low noise when operating in the ambient environment. When tested with a set of frequency switchable quantum cascade lasers (QCLs) for multicolor illumination, both MM-FPAs and QCLs can be tuned to operate at multiple discrete THz frequencies to match analyte "fingerprints." Versatile imaging capabilities are presented, including unambiguous identification of concealed substances with intrinsic and/or human-engineered THz characteristics as well as effective diagnosis of cancerous tissues without notable spectral signatures in the THz range, underscoring the utility of applying multispectral approaches in this compelling wavelength range for sensing/identification and medical imaging.

11.
Proc Natl Acad Sci U S A ; 115(32): 8119-8124, 2018 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-30037994

RESUMO

The interaction between light and matter has been long explored, leading to insights based on the modulation and control of electrons and/or photons within a material. An opportunity exists in optomechanics, where the conversion of radiation into material strain and actuation is currently induced at the molecular level in liquid crystal systems, or at the microelectromechanical systems (MEMS) device scale, producing limited potential strain energy (or force) in light-driven systems. We present here flexible material composites that, when illuminated, are capable of macroscale motion, through the interplay of optically absorptive elements and low Curie temperature magnetic materials. These composites can be formed into films, sponges, monoliths, and hydrogels, and can be actuated with light at desired locations. Light-actuated elastomeric composites for gripping and releasing, heliotactic motion, light-driven propulsion, and rotation are demonstrated as examples of the versatility of this approach.

12.
Chem Soc Rev ; 47(17): 6486-6504, 2018 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-29938722

RESUMO

Silks are natural fibrous protein polymers that are spun by silkworms and spiders. Among silk variants, there has been increasing interest devoted to the silkworm silk of B. mori, due to its availability in large quantities along with its unique material properties. Silk fibroin can be extracted from the cocoons of the B. mori silkworm and combined synergistically with other biomaterials to form biopolymer composites. With the development of recombinant DNA technology, silks can also be rationally designed and synthesized via genetic control. Silk proteins can be processed in aqueous environments into various material formats including films, sponges, electrospun mats and hydrogels. The versatility and sustainability of silk-based materials provides an impressive toolbox for tailoring materials to meet specific applications via eco-friendly approaches. Historically, silkworm silk has been used by the textile industry for thousands of years due to its excellent physical properties, such as lightweight, high mechanical strength, flexibility, and luster. Recently, due to these properties, along with its biocompatibility, biodegradability and non-immunogenicity, silkworm silk has become a candidate for biomedical utility. Further, the FDA has approved silk medical devices for sutures and as a support structure during reconstructive surgery. With increasing needs for implantable and degradable devices, silkworm silk has attracted interest for electronics, photonics for implantable yet degradable medical devices, along with a broader range of utility in different device applications. This Tutorial review summarizes and highlights recent advances in the use of silk-based materials in bio-nanotechnology, with a focus on the fabrication and functionalization methods for in vitro and in vivo applications in the field of tissue engineering, degradable devices and controlled release systems.


Assuntos
Materiais Biocompatíveis/química , Bioengenharia/métodos , Bombyx/química , Nanoestruturas/química , Nanotecnologia/métodos , Seda/química , Animais , Materiais Biocompatíveis/metabolismo , Bioengenharia/instrumentação , Bombyx/genética , Bombyx/metabolismo , Sistemas de Liberação de Medicamentos/instrumentação , Sistemas de Liberação de Medicamentos/métodos , Desenho de Equipamento , Engenharia Genética/instrumentação , Engenharia Genética/métodos , Humanos , Nanoestruturas/ultraestrutura , Nanotecnologia/instrumentação , Seda/genética , Seda/metabolismo , Seda/ultraestrutura , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos
13.
Adv Mater ; 30(25): e1800598, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29717798

RESUMO

The increased need for wearable and implantable medical devices has driven the demand for electronics that interface with living systems. Current bioelectronic systems have not fully resolved mismatches between engineered circuits and biological systems, including the resulting pain and damage to biological tissues. Here, salt/poly(ethylene glycol) (PEG) aqueous two-phase systems are utilized to generate programmable hydrogel ionic circuits. High-conductivity salt-solution patterns are stably encapsulated within PEG hydrogel matrices using salt/PEG phase separation, which route ionic current with high resolution and enable localized delivery of electrical stimulation. This strategy allows designer electronics that match biological systems, including transparency, stretchability, complete aqueous-based connective interface, distribution of ionic electrical signals between engineered and biological systems, and avoidance of tissue damage from electrical stimulation. The potential of such systems is demonstrated by generating light-emitting diode (LED)-based displays, skin-mounted electronics, and stimulators that deliver localized current to in vitro neuron cultures and muscles in vivo with reduced adverse effects. Such electronic platforms may form the basis of future biointegrated electronic systems.


Assuntos
Hidrogéis/química , Materiais Biocompatíveis , Hidrogel de Polietilenoglicol-Dimetacrilato , Íons , Polietilenoglicóis , Próteses e Implantes
14.
Acta Biomater ; 71: 379-387, 2018 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-29550442

RESUMO

Freeform fabrication has emerged as a key direction in printing biologically-relevant materials and structures. With this emerging technology, complex structures with microscale resolution can be created in arbitrary geometries and without the limitations found in traditional bottom-up or top-down additive manufacturing methods. Recent advances in freeform printing have used the physical properties of microparticle-based granular gels as a medium for the submerged extrusion of bioinks. However, most of these techniques require post-processing or crosslinking for the removal of the printed structures (Miller et al., 2015; Jin et al., 2016) [1,2]. In this communication, we introduce a novel method for the one-step gelation of silk fibroin within a suspension of synthetic nanoclay (Laponite) and polyethylene glycol (PEG). Silk fibroin has been used as a biopolymer for bioprinting in several contexts, but chemical or enzymatic additives or bulking agents are needed to stabilize 3D structures. Our method requires no post-processing of printed structures and allows for in situ physical crosslinking of pure aqueous silk fibroin into arbitrary geometries produced through freeform 3D printing. STATEMENT OF SIGNIFICANCE: 3D bioprinting has emerged as a technology that can produce biologically relevant structures in defined geometries with microscale resolution. Techniques for fabrication of free-standing structures by printing into granular gel media has been demonstrated previously, however, these methods require crosslinking agents and post-processing steps on printed structures. Our method utilizes one-step gelation of silk fibroin within a suspension of synthetic nanoclay (Laponite), with no need for additional crosslinking compounds or post processing of the material. This new method allows for in situ physical crosslinking of pure aqueous silk fibroin into defined geometries produced through freeform 3D printing.


Assuntos
Fibroínas/química , Impressão Tridimensional , Animais , Bombyx
15.
Adv Mater ; 30(20): e1705919, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29582487

RESUMO

Precise patterning of polymer-based biomaterials for functional bio-nanostructures has extensive applications including biosensing, tissue engineering, and regenerative medicine. Remarkable progress is made in both top-down (based on lithographic methods) and bottom-up (via self-assembly) approaches with natural and synthetic biopolymers. However, most methods only yield 2D and pseudo-3D structures with restricted geometries and functionalities. Here, it is reported that precise nanostructuring on genetically engineered spider silk by accurately directing ion and electron beam interactions with the protein's matrix at the nanoscale to create well-defined 2D bionanopatterns and further assemble 3D bionanoarchitectures with shape and function on demand, termed "Protein Bricks." The added control over protein sequence and molecular weight of recombinant spider silk via genetic engineering provides unprecedented lithographic resolution (approaching the molecular limit), sharpness, and biological functions compared to natural proteins. This approach provides a facile method for patterning and immobilizing functional molecules within nanoscopic, hierarchical protein structures, which sheds light on a wide range of biomedical applications such as structure-enhanced fluorescence and biomimetic microenvironments for controlling cell fate.

16.
Adv Mater ; 30(18): e1703257, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29572979

RESUMO

Wearable devices have emerged as powerful tools for personalized healthcare in spite of some challenges that limit their widespread applicability as continuous monitors of physiological information. Here, a materials-based strategy to add utility to traditional dielectric sensors by developing a conformal radiofrequency (RF) construct composed of an active layer encapsulated between two reverse-facing split ring resonators is applied. These small (down to 2 mm × 2 mm) passive dielectric sensors possess enhanced sensitivity and can be further augmented by functionalization of this interlayer material. Demonstrator devices are shown where the interlayer is: (i) a porous silk film, and (ii) a modified PNIPAM hydrogel that swells with pH or temperature. In vivo use is demonstrated by adhesion of the device on tooth enamel to detect foods during human ingestion. Such sensors can be easily multiplexed and yield data-rich temporal information during the diffusion of analytes within the trilayer structure. This format could be extended to a suite of interlayer materials for sensing devices of added use and specificity.


Assuntos
Boca , Alimentos , Humanos
17.
Opt Lett ; 42(23): 4857-4860, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29216128

RESUMO

Spectral and coherence evolutions were measured for supercontinuum (SC) generated in a 2.7 cm highly nonlinear tellurite photonic crystal fiber. Numerical simulations were performed based on the generalized nonlinear Schrödinger equation with noise. The measurements show that coherence degradation first occurs after soliton fission, and then spreads to longer wavelengths as the average power of the SC increases. The solitonic coherence shows much slower degradation than the overall coherence.

18.
Opt Express ; 25(16): 18842-18852, 2017 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-29041076

RESUMO

We present experimental measurements illustrating the power-dependent coherence evolution for supercontinuum generated in highly nonlinear SF6 photonic crystal fibers. The measurements were performed for fiber lengths close to and much longer than the soliton fission length. Simulations of the spectral evolution were also carried out to accompany the experimental observation. Many parameters were estimated by matching the simulated and the measured evolution. Both the measured and the simulated coherence evolution confirm the association between coherence degradation and soliton fission.

19.
Adv Sci (Weinh) ; 4(9): 1700191, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28932678

RESUMO

Precise patterning of biomaterials has widespread applications, including drug release, degradable implants, tissue engineering, and regenerative medicine. Patterning of protein-based microstructures using UV-photolithography has been demonstrated using protein as the resist material. The Achilles heel of existing protein-based biophotoresists is the inevitable wide molecular weight distribution during the protein extraction/regeneration process, hindering their practical uses in the semiconductor industry where reliability and repeatability are paramount. A wafer-scale high resolution patterning of bio-microstructures using well-defined silk fibroin light chain as the resist material is presented showing unprecedent performances. The lithographic and etching performance of silk fibroin light chain resists are evaluated systematically and the underlying mechanisms are thoroughly discussed. The micropatterned silk structures are tested as cellular substrates for the successful spatial guidance of fetal neural stems cells seeded on the patterned substrates. The enhanced patterning resolution, the improved etch resistance, and the inherent biocompatibility of such protein-based photoresist provide new opportunities in fabricating large scale biocompatible functional microstructures.

20.
ACS Appl Mater Interfaces ; 9(36): 30951-30957, 2017 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-28820237

RESUMO

The use of biomaterials as optical components has recently attracted attention because of their ease of functionalization and fabrication, along with their potential use when integrated with biological materials. We present here an observation of the optical properties of a silk-azobenzene material (Azosilk) and demonstrate the operation of an Azosilk/PDMS composite structure that serves as a conformable and switchable optical diffractive structure. Characterization of thermal and isomeric properties of the device, along with its overall performance, is presented in terms of diffractive characteristics and response times. The ease of manufacturing and functionalization opens a promising avenue for rapid device prototyping and interfaces of expanded utility.

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