New Opportunities for an Ancient Material Omenetto, Fiorenzo G; Kaplan, David L
Science (American Association for the Advancement of Science),
07/2010, Letnik:
329, Številka:
5991
Journal Article
Recenzirano
Odprti dostop
Spiders and silkworms generate silk protein fibers that embody strength and beauty. Orb webs are fascinating feats of bioengineering in nature, displaying magnificent architectures while providing ...essential survival utility for spiders. The unusual combination of high strength and extensibility is a characteristic unavailable to date in synthetic materials yet is attained in nature with a relatively simple protein processed from water. This biological template suggests new directions to emulate in the pursuit of new high-performance, multifunctional materials generated with a green chemistry and processing approach. These bio-inspired and high-technology materials can lead to multifunctional material platforms that integrate with living systems for medical materials and a host of other applications.
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.
Silks are natural fibrous protein polymers that are spun by silkworms and spiders. This
tutorial review
summarizes and highlights recent advances in the use of silkworm silk-based materials in bio-nanotechnology.
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.
A small‐form‐factor, biopolymer‐based layered radiofrequency sensor is developed for sensing various solutes, pH, and temperature. An interchangeable sensitive layer determines the response to either analyte‐induced dielectric change, or pH‐ and temperature‐induced mechanical change. On‐tooth sensing is demonstrated for tracking of food intake.
Abstract Silks are appealing materials for numerous biomedical applications involving drug delivery, tissue engineering, or implantable devices, because of their tunable mechanical properties and ...wide range of physical structures. In addition to the functionalities needed for specific clinical applications, a key factor necessary for clinical success for any implanted material is appropriate interactions with the body in vivo . This review summarizes our current understanding of the in vivo biological responses to silks, including degradation, the immune and inflammatory response, and tissue remodeling with particular attention to vascularization. While we focus in this review on silkworm silk fibroin protein due to the large quantity of in vivo data thanks to its widespread use in medical materials and consumer products, spider silk information is also included if available. Silk proteins are degraded in the body on a time course that is dependent on the method of silk fabrication and can range from hours to years. Silk protein typically induces a mild inflammatory response that decreases within a few weeks of implantation. The response involves recruitment and activation of macrophages and may include activation of a mild foreign body response with the formation of multinuclear giant cells, depending on the material format and location of implantation. The number of immune cells present decreases with time and granulation tissue, if formed, is replaced by endogenous, not fibrous, tissue. Importantly, silk materials have not been demonstrated to induce mineralization, except when used in calcified tissues. Due to its ability to be degraded, silk can be remodeled in the body allowing for vascularization and tissue ingrowth with eventual complete replacement by native tissue. The degree of remodeling, tissue ingrowth, or other specific cell behaviors can be modulated with addition of growth or other signaling factors. Silk can also be combined with numerous other materials including proteins, synthetic polymers, and ceramics to enhance its characteristics for a particular function. Overall, the diverse array of silk materials shows excellent bioresponses in vivo with low immunogenicity and the ability to be remodeled and replaced by native tissue making it suitable for numerous clinical applications.
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.
Two noncontact, rapid, and direct strategies for patterning of biopolymer‐based photonic crystals using inkjet printing are presented. Multispectral responses generated from the photonic lattice as a result of interactions with the deposition ink and environments suggest opportunities in exploiting biomaterials with optical assets as functional interfaces such as message encryption.
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.
Electron-electron interactions can render an otherwise conducting material insulating, with the insulator-metal phase transition in correlated-electron materials being the canonical macroscopic ...manifestation of the competition between charge-carrier itinerancy and localization. The transition can arise from underlying microscopic interactions among the charge, lattice, orbital and spin degrees of freedom, the complexity of which leads to multiple phase-transition pathways. For example, in many transition metal oxides, the insulator-metal transition has been achieved with external stimuli, including temperature, light, electric field, mechanical strain or magnetic field. Vanadium dioxide is particularly intriguing because both the lattice and on-site Coulomb repulsion contribute to the insulator-to-metal transition at 340 K (ref. 8). Thus, although the precise microscopic origin of the phase transition remains elusive, vanadium dioxide serves as a testbed for correlated-electron phase-transition dynamics. Here we report the observation of an insulator-metal transition in vanadium dioxide induced by a terahertz electric field. This is achieved using metamaterial-enhanced picosecond, high-field terahertz pulses to reduce the Coulomb-induced potential barrier for carrier transport. A nonlinear metamaterial response is observed through the phase transition, demonstrating that high-field terahertz pulses provide alternative pathways to induce collective electronic and structural rearrangements. The metamaterial resonators play a dual role, providing sub-wavelength field enhancement that locally drives the nonlinear response, and global sensitivity to the local changes, thereby enabling macroscopic observation of the dynamics. This methodology provides a powerful platform to investigate low-energy dynamics in condensed matter and, further, demonstrates that integration of metamaterials with complex matter is a viable pathway to realize functional nonlinear electromagnetic composites.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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.
Programmable hydrogel ionic circuits completely composed of salt, water, and biofriendly hydrogels are developed based on salt/poly(ethylene glycol) aqueous two‐phase systems. Such systems enable designer electronics that match the properties of biological systems and route high‐resolution ionic electrical signals between engineered and living systems while avoiding tissue damage. Such platforms may form the basis of future biointegrated electronic systems.
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