Combining GA with Splitting Methods for Rearrangeably Nonblocking Grooming of Dynamic Traffic in SONET Ring Networks

SONET/WDM rings are widely deployed in today’s networks. To reduce the total cost of such a network, an efficient way is using the traffic grooming technique to minimize the number of add/drop multiplexers (ADMs) on the ring. Since traffic often changes frequently, the problem of supporting dynamic traffic patterns with minimum number of ADMs and wavelengths becomes incresingly important, which is referred to as grooming of dynamic traffic. In this paper, we will deal with rearrangeably nonblocking grooming of arbitrary dynamic traffic in such ring networks. We will discuss in detail the benefit of splitting methods to such a grooming way and apply them to this kind of grooming. A novel genetic algorithm (GA) approach with a hierarchical chromosome structure for each individual is proposed in combination with splitting methods to address such grooming problems. Computer simulation results under different conditions show that our algorithm is efficient in reducing both the numbers of ADMs and wavelengths.     

Tunable Chemical and Topographic Patterns Based on Binary Colloidal Crystals (BCCs) to Modulate MG63 Cell Growth

More effective and diversified surface modification strategies are required for materials used in biomedical engineering. Combining surface modification involving bioactive signals or nonfouling polymers with tunable topography has the potential to meet this need. Here, a method is reported to generate bioactive surfaces having tunable topographies based on self‐assembled binary colloidal crystals (BCCs), where the colloids are premodified with nonfouling molecules or cell adhesive peptides. The BCCs are fabricated from silica (Si) microspheres and polymer nanospheres. The Si microspheres are either modified with poly(ethylene glycol) (PEG) or with the cell adhesive arginine–glycine–aspartic acid (RGD) peptide prior to BCC fabrication. Four types of BCCs are explored in cell studies using MG63 cells. BCC surfaces coupled with PEG or RGD peptides are found to significantly modulate cell adhesion, spreading, and morphology, which is attributed to the combination of BCC topography and the molecules at the particle surface within the BCC. PEG‐modified BCCs are expected to find applications where limited cell adhesion is required, while the RGD‐modified BCCs have the potential for enhancing cell growth on medical devices such as bone implants. More advanced cell biology applications such as controlled stem cell differentiation are also anticipated to find use from BCCs.     

Bio‐Inspired Synthesis of Minerals for Energy,Environment, and Medicinal Applications

Biomineralization, the natural pathway of assembling biogenic inorganic compounds, inspires us to exploit unique, effective strategies to fabricate functional materials with intricate structures. In this article, the recent advances in bio‐inspired synthesis of minerals—with a focus on those of calcium‐based minerals—and their applications to the design of functional materials for energy, environment, and biomedical fields are reviewed. Biomimetic mineralization is extending its application range to unconventional area such as the design of component materials for lithium‐ion batteries and elaborately structured composite materials utilizing carbon dioxide gas. Materials with highly enhanced mechanical properties are synthesized through emulating the nacre structure. Studies of bioactive minerals‐carbon hybrid materials show an expansion of potential applications to fields ranging from interdisciplinary science to practical engineering such as the fabrication of reinforced bone‐implantable materials.     

Silicon‐Based Laser Desorption Ionization Mass Spectrometry for the Analysis of Biomolecules: A Progress Report

Matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) is widely used in the biomedical field for the label‐free analysis of molecules such as drugs, lipids, peptides, proteins, and biological tissues for molecular imaging. However, organic matrices used in traditional MALDI‐MS applications introduce excessive interferences in the low m/z range. For this reason, nanostructured materials—and in particular silicon‐based LDI strategies—have become a promising alternative, since they provide a much weaker background. Herein, the recent developments in fabrication, functionalization, and practical applications of silicon‐based LDI‐MS methods are reviewed. Also the basic requirements of silicon‐based substrates for optimal LDI analysis by providing an overview of the LDI mechanisms that use silicon‐based substrates instead of organic matrices are reported. Finally, the considerable potential of silicon‐based substrates is discussed, giving suggestions for topics for future research.     

Edible Electronics: Biocompatible and Biodegradable Materials for Organic Field‐Effect Transistors (Adv. Funct. Mater. 23/2010)

Biocompatible‐ingestible electronic circuits and capsules for medical diagnosis and monitoring are currently based on traditional silicon technology. Organic electronics has huge potential for developing biodegradable, biocompatible, bioresorbable, or even metabolizable products. An ideal pathway for such electronic devices involves fabrication with materials from nature, or materials found in common commodity products. Transistors with an operational voltage as low as 4–5 V, a source drain current of up to 0.5 μA and an on‐off ratio of 3–5 orders of magnitude have been fabricated with such materials. This work comprises steps towards environmentally safe devices in low‐cost, large volume, disposable or throwaway electronic applications, such as in food packaging, plastic bags, and disposable dishware. In addition, there is significant potential to use such electronic items in biomedical implants.     

In Situ Production of Biofunctionalized Few‐Layer Defect‐Free Microsheets of Graphene

Biological interfacing of graphene has become crucial to improve its biocompatibility, dispersability, and selectivity. However, biofunctionalization of graphene without yielding defects in its sp²‐carbon lattice is a major challenge. Here, a process is set out for biofunctionalized defect‐free graphene synthesis through the liquid phase ultrasonic exfoliation of raw graphitic material assisted by the self‐assembling fungal hydrophobin Vmh2. This protein (extracted from the edible fungus Pleurotus ostreatus) is endowed with peculiar physicochemical properties, exceptional stability, and versatility. The unique properties of Vmh2 and, above all, its superior hydrophobicity, and stability allow to obtain a highly concentrated (≈440–510 μg mL^?1) and stable exfoliated material (ζ‐potential, +40/+70 mV). In addition controlled centrifugation enables the selection of biofunctionalized few‐layer defect‐free micrographene flakes, as assessed by Raman spectroscopy, atomic force microscopy, scanning electron microscopy, and electrophoretic mobility. This biofunctionalized product represents a high value added material for the emerging applications of graphene in the biotechnological field such as sensing, nanomedicine, and bioelectronics technologies.     

Wavelength Assignment to Minimize the Number of SONET ADMs in WDM Rings*†

Optical wavelength division multiplexing (WDM) rings are being deployed to support SONET/SDH self-healing rings. In such systems, multiple SONET/SDH self-healing rings are realized over a single physical optical ring through wavelength division multiplexing. The cost of such a system is dominated by the SONET add/drop multiplexers (ADMs). To minimize the system cost, algorithms must be developed to assign wavelengths to lightpaths in the system so that the number of ADMs required is minimized. This problem of optimal wavelength assignment to minimize the number of SONET ADMs is known to be NP-hard. Existing heuristic algorithms for this problem include the assign first heuristic, the iterative matching heuristic and the iterative merging heuristic. In this paper, we develop an integer linear programming (ILP) formulation for this problem, propose a new wavelength assignment heuristic, and evaluate the existing and the newly proposed heuristic using the ILP formulation. We conclude that the performance of the newly proposed heuristic is very close to optimal.     

Biocompatible and Biodegradable Materials for Organic Field‐Effect Transistors

Biocompatible‐ingestible electronic circuits and capsules for medical diagnosis and monitoring are currently based on traditional silicon technology. Organic electronics has huge potential for developing biodegradable, biocompatible, bioresorbable, or even metabolizable products. An ideal pathway for such electronic devices involves fabrication with materials from nature, or materials found in common commodity products. Transistors with an operational voltage as low as 4–5 V, a source drain current of up to 0.5 μA and an on‐off ratio of 3–5 orders of magnitude have been fabricated with such materials. This work comprises steps towards environmentally safe devices in low‐cost, large volume, disposable or throwaway electronic applications, such as in food packaging, plastic bags, and disposable dishware. In addition, there is significant potential to use such electronic items in biomedical implants.     

Plastic Solar Cells

Recent developments in conjugated‐polymer‐based photovoltaic elements are reviewed. The photophysics of such photoactive devices is based on the photo‐induced charge transfer from donor‐type semiconducting conjugated polymers to acceptor‐type conjugated polymers or acceptor molecules such as Buckminsterfullerene, C₆₀. This photo‐induced charge transfer is reversible, ultrafast (within 100 fs) with a quantum efficiency approaching unity, and the charge‐separated state is metastable (up to milliseconds at 80 K). Being similar to the first steps in natural photosynthesis, this photo‐induced electron transfer leads to a number of potentially interesting applications, which include sensitization of the photoconductivity and photovoltaic phenomena. Examples of photovoltaic architectures are presented and their potential in terrestrial solar energy conversion discussed. Recent progress in the realization of improved photovoltaic elements with 3 % power conversion efficiency is reported.     

Enzyme‐Driven Hasselback‐Like DNA‐Based Inorganic Superstructures

DNA structures have gained much attention due to its ease of self‐assembly and precise controllability. Although DNA technology has been successfully applied to generate a variety of DNA structures, there are only few attempts to apply DNA technology to generate inorganic materials due to lack of controllability of interactions between DNA and inorganic materials. In addition, the synthesis of a predictable structure of hybrid materials still remains a significant challenge. To address the challenge, here a novel strategy for the synthesis of DNA‐based inorganic superstructures using DNA polymerase is reported. In particular, strategic feeding of metal ions for generating DNA‐inorganic hybrid superstructures during DNA polymerization is established. This approach can produce a variety of structures with varying metal ions and can easily add functionality to the product. The structural features are also easily studied by first‐principles calculations. With these advantages, DNA‐Mn particles show the potential as a cell tracking agent, a contrast agent for MRI, and an electrode material for supercapacitors. The enzyme‐driven synthesis in this study will provide a novel route for the generation of a range of organic–inorganic hybrid superstructures for biomedical and energy applications.     

Biomimetic Ultralight,Highly Porous,Shape‐Adjustable,and Biocompatible 3D Graphene Minerals via Incorporation of Self‐Assembled Peptide Nanosheets

Hybrid nanomaterials with tailored functions, consisting of self‐assembled peptides, are intensively applied in nanotechnology, tissue engineering, and biomedical applications due to their unique structures and properties. Herein, a peptide‐mediated biomimetic strategy is adopted to create the multifunctional 3D graphene foam (GF)‐based hybrid minerals. First, 2D peptide nanosheets (PNSs), obtained by self‐assembling a motif‐specific peptide molecule (LLVFGAKMLPHHGA), are expected to exhibit biofunctionality, such as the biomimetic mineralization of hydroxyapatite (HA) minerals. Subsequently, the noncovalent conjugation of PNSs onto GF support is utilized to form 3D GF‐PNSs hybrid scaffolds, which are suitable for the growth of HA minerals. The fabricated biomimetic 3D GF‐PNSs‐HA minerals exhibit adjustable shape, superlow weight (0.017 g cm^?3), high porosity (5.17 m² g^?1), and excellent biocompatibility, proving potential applications in both bone tissue engineering and biomedical engineering. To the best of the authors' knowledge, it is the first time to combine 2D PNSs and GF to fabricate 3D organic–inorganic hybrid scaffold. Further development of these hybrid GF‐PNSs scaffolds can potentially lead to materials used as matrices for drug delivery or bone tissue engineering as proven via successful 3D scaffold formation exhibiting interconnected pore‐size structures suitable for vascularization and medium transport.     

Copper‐Free Clickable Coatings

The copper‐catalyzed azide–alkyne 1,3‐dipolar cycloaddition (CuAAC) is extensively used for the functionalization of well‐defined polymeric materials. However, the necessity for copper, which is inherently toxic, limits the potential applications of these materials in the area of biology and biomedicine. Therefore, the first entirely copper‐free procedure for the synthesis of clickable coatings for the immobilization of functional molecules is reported. In the first step, azide‐functional coatings are prepared by thermal crosslinking of side‐chain azide‐functional polymers and dialkyne linkers. In a second step, three copper‐free click reactions (i.e., the Staudinger ligation, the dibenzocyclooctyne‐based strain‐promoted azide–alkyne [3+2] cycloaddition, and the methyl‐oxanorbornadiene‐based tandem cycloaddition?retro‐Diels?Alder (crDA) reaction) are used to functionalize the azide‐containing surfaces with fluorescent probes, allowing qualitative comparison with the traditional CuAAC.     

Protein Particles Formed by Protein Activation and Spontaneous Self‐Assembly

In this article, a non‐chemical crosslinking method is used to produce pure protein microparticles with an innovative approach, so‐called protein activation spontaneous and self‐assembly (PASS). The fabrication of protein microparticles is based on the idea of using the internal disulfide bridges within protein molecules as molecular linkers to assemble protein molecules into a microparticle form. The assembly process is triggered by an activating reagent–dithiothreitol (DTT), which only involved in the intermediate step without being incorporated into the resulting protein microparticles. Conventional protein microparticle fabrication methods usually involve emulsification process and chemical crosslink reactions using amine reactive reagents such as glutaraldehdye or EDC/NHS. The resulting protein microparticles are usually having various size distributions. Most importantly crosslinking reactions using amine reactive reagents will result in producing protein microparticles with undesired properties such as auto‐fluorescence and high toxicity. In contrast to the conventional methods, our technology provides a simple and robust method to produce highly homogeneous, stable and non‐fluorescence pure protein microparticles under mild conditions at physiological pH and temperature. The protein microparticles are found to be biodegradable, non‐toxic to MDCK cells and with preserved biological activities. Results on the cytotoxcity study and enzyme function demonstrate the potential applications of the protein microparticles in the area of pharmaceutics and analytical chemistry.     

Multifunctional Fibers to Shape Future Biomedical Devices

Fiber‐based configurations are highly desirable for wearable and implantable biomedical devices due to their unique properties, such as ultra‐flexibility, weavability, minimal invasiveness, and tissue adaptability. Recent developments have focused on the fabrication of fibrous devices with multiple biomedical functions, such as noninvasively or minimally invasively monitoring of physiological signals, delivering drugs, transplanting cells, and recording and stimulating nerves. In this Review, the recent progress of these multifunctional fiber‐based devices in terms of their composite materials, fabrication techniques, structural designs, device‐tissue interfaces, and biomedical applications is carefully described. The remaining challenges and future directions in this emerging and exciting research field are also highlighted.     

Mesoporous Protein Particles Through Colloidal CaCO3 Templates

Porous colloidal particles can be tailored using templating techniques to maximize their effectiveness for a wide range of applications, including separation, catalysis, and drug delivery. However, templating usually involves harsh and complex preparation conditions, thereby complicating the fabrication of sensitive bio‐functionalized particles. Here a simple, yet versatile and mild approach us used to create porous protein particles using mesoporous CaCO₃ colloids as sacrificial templates. The three‐step preparation procedure involves infiltrating the colloidal templates with the protein by solvent evaporation, protein crosslinking, and removal of CaCO₃. Using this method one can obtain porous particles consisting of virtually any protein. To explore the applicability of the particles for various scenarios particles composed of different proteins are fabricated focusing on hemoglobin and trypsin and particle morphology, porosity, mechanical properties, the protein redox state, and enzymatic activity are determined. The results show that the nanoporous template structure is replicated and that the proteins are fully functional. By varying preparation conditions such as crosslinker concentration and protein content the elastic modulus is adjusted in the range of red blood cells. This ensures high deformability upon flow in microchannels and makes the porous protein particles a versatile platform for biomedical applications.     

Biodegradable Frequency‐Selective Magnesium Radio‐Frequency Microresonators for Transient Biomedical Implants

Bioresorbable implantable medical devices show a great potential for applications requiring medical care over well‐defined periods of time. Once their function is fulfilled, such implants naturally degrade and resorb in the body, which eliminates adverse long‐term effects or the need for a secondary surgery to extract the implanted device. Since biodegradable materials are water‐soluble, the fabrication of such transient electronic circuits and devices requires special care and needs to rely solely on dry processing steps without exposure to aqueous solutions. A further challenge is the in vivo powering of medical implants that are only constituted of biodegradable materials. This paper describes the design, fabrication, and testing of radio‐frequency biodegradable magnesium microresonators. To this end, an innovative microfabrication process with minimal exposure to aqueous media is developed to fabricate magnesium‐based, water‐soluble electronic components. It consists of a novel sequence of only three steps: one physical vapor deposition, one photolithography, and one ion beam etching step. The frequency‐selective wireless heating of different resonators is demonstrated. This represents a significant step toward their use as power receivers and microheaters in biodegradable implantable medical devices, for applications such as triggered drug release.     

Two‐Dimensional Assembly of Symmetric Colloidal Dimers under Electric Fields

Like atoms and molecules with directional interactions, anisotropic particles could potentially assemble into a much wider range of crystalline arrays and meso‐structures than spherical particles with isotropic interactions. In this paper, the electric‐field directed assembly of geometrically anisotropic particles–colloidal dimers is studied. Rich phase behavior and different assembly regimes are found, primarily arising from the broken radial symmetry in particles. The orientations of individual dimers depend on the frequency of the electric field, the ramping direction of frequency, and the salt concentration. The competition and balance between the hydrodynamic, electric, and Brownian torques determine the orientation of individual particles, while the competition between the electrohydrodynamic force and dipolar interaction determines the aggregation of aligned particles at a given experimental condition. The field distribution near the electrode is critical to understand the orientation and assembly behavior of colloidal dimers on a conducting substrate. This study also demonstrates the effectiveness, the reversibility, and potential opportunity of applying electric field to control the orientation and direct the assembly of non‐spherical particles. In particular, two dimensional close‐packed crystals of perpendicularly aligned dimers are obtained, which shows promise in fabricating 3D photonic crystals based on dimer‐like colloids and field‐directed display.     

Targeted Single‐Cell Therapeutics with Magnetic Tubular Micromotor by One‐Step Exposure of Structured Femtosecond Optical Vortices

Selective manipulation of specific single cells for therapeutics is important and highly desirable in biomedical research. As a simple and maneuverable tool, tubular micromotors have displayed appealing applications in encapsulation and transportation of cells. However, so far there are no reports on the simultaneous transportation of target single cells and the drugs with microtubes in a custom arrayed environment for targeted therapeutics. Moreover, fabrication of microtubes with 3D features in a reproducible and single‐step fashion, while, endowing them with the ability of remote control, remains challenging. In this study, a novel method for one‐step fabrication of magnetic 3D tubular micromotors by single exposure of structured optical vortices in a magnetic photoresist is presented. The size and geometry of fabricated microtubes are flexibly controlled in three dimensions. Precise propelling of the tubular micromotors and precise capture, targeted delivery, and release of SiO₂ microparticles are realized. Finally, as a proof‐of‐concept demonstration, in situ observation of the development of doxorubicin in Hela cells for therapeutic study is performed by targeted delivery of single cells and drug particles. The technology is simple and stable, which has promising applications in targeted cell therapy, drug screening, single cell studies, and other biomedical areas.     

Plant‐Inspired Pyrogallol‐Containing Functional Materials

Pyrogallol‐containing molecules are ubiquitous in the plant kingdom. The chemical synthesis of these molecules remains challenging. Thus, they are obtained via purification from heterogeneous mixtures of plant extracts. Previous studies have focused on their biological roles, such as antioxidants. Additionally, the molecules are used as ink colorants and in tanning processes for leather. Recently, many disciplines have paid attention to adhesiveness of pyrogallol‐containing molecules, including the control of interface properties in energy storage/generation and medical devices, as well as the changes in wettability related to membrane technologies. In particular, pyrogallol‐containing molecules act as “molecular glues,” binding to virtually all biomacromolecules, for example, DNA/RNA, soluble proteins, insoluble extracellular matrices, and peptides. Furthermore, the cohesion of pyrogallol by forming pyrogallol‐to‐pyrogallol covalent bonds is useful for the preparation of bulk hydrogels and thin films. The content of this review focuses on interactions with biomacromolecules used as molecular glues, used as modifiers in material‐independent surface chemistry, and applied as chemical moieties to form covalent linkages to fabricate hydrogels and related biomaterials. Future perspectives include the development of new pyrogallol‐containing materials, the understanding of chirality in adhesion, and the improvement of the mechanical stability for applications in various biomedical, energy, and industrial devices.     

Recombinant Spider Silk as Mediator for One‐Step,Chemical‐Free Surface Biofunctionalization

A unique strategy for effective, versatile, and facile surface biofunctionalization employing a recombinant spider silk protein genetically functionalized with the antibody‐binding Z domain (Z‐4RepCT) is reported. It is demonstrated that Z‐silk can be applied to a variety of materials and platform designs as a truly one‐step and chemical‐free surface modification that site specifically captures antibodies while simultaneously reducing nonspecific adsorption. As a model surface, SiO₂ is used to optimize and characterize Z‐silk performance compared to the Z domain immobilized by a standard silanization method. First, Z‐silk adsorption is investigated and verified its biofunctionality in a long‐term stability experiment. To assess the binding capacity and protein–protein interaction stability of Z‐silk, the coating is used to capture human antibodies in various assay formats. An eightfold higher binding capacity and 40‐fold lower detection limit are obtained in the immunofluorescence assay, and the complex stability of captured antibodies is shown to be improved by a factor of 20. Applicability of Z‐silk to functionalize microfluidic devices is demonstrated by antibody detection in an electrokinetic microcapillary biosensor. To test Z‐silk for biomarker applications, real‐time detection and quantification of human immunoglobulin G are performed in a plasma sample and C1q capture from human serum using an anti‐C1q antibody.