Ortselektive laserchemische Oberflächenfunktionalisierung von Polymeren im Mikrometerbereich. Selective laser‐chemical micro surface modification of polymers

Polymeric substrate materials like polystyrene (PS), polycarbonate (PC) or cyclic olefins (COC) are getting more attention besides silica, glass and ceramic for the preparation of reaction vessels, optical slides, microfluidic components or microtiterplates in applications like medical diagnostics and pharmaceutical drug screening. Actually, the market of transparent polymeric chips is demanding the availability of modified surfaces with well defined arrays of wettable areas or special chemical functionalities. The modified areas are starting point to graft bioactive molecules, for instance proteins or DNA‐oligomers. Another application is pretreatment of adhesive bonded joints. Presently surface modifications are performed chemically and physically by plasma surface interaction. IWS has developed a new technique for dry chemical structuring of polymeric surfaces based on the principle of excimer laser irradiation in reactive gas atmosphere. This technique is characterized by a high resolution and a negligible amount of chemicals. The procedure consists of only a few processing steps, in contrast to conventional lithographic structuring methods. Also wetting problems do not play a role as they do in printing techniques. The technology provides the possibility of tailoring the chemical and topographical surface properties from ultrahydrophobic to hydrophilic or to functionalize areas of choice in the μm range with a chemical group of defined density. Using an excimer‐laser to induce reactions, mask imaging can be applied for microstructuring the surface with new properties, e. g. for microarrays. In addition, the laser allows defined amount of energy into the elementary reaction, according to the wavelength applied, which opens the possibility of replacing atoms in the polymer molecules by other atoms or molecules taken from an agent in the environment, in a selective way. The precondition is that both the polymer and the agent absorb the same wavelength. For instance 193 nm radiation (ArF excimer laser) is absorbed by polyolefines and by ammonia allowing an exchange of H atoms for amino groups by which the surface is changed to starting point to graft bioactive molecules. Chemical microstructures for instance amino group arrays have been realized on a variety of polymeric materials like cyclic olefin foil. This array of monofunctionality is the starting point for the preparation of parallel microreactors. These samples of topographical and chemical microstructures are the first step for biochemical preparations in medical diagnostic kits, DNA‐, protein‐ or cell biochips. The upscaling of the laser modification process in a multi‐chamber reactor offers the semicontinuous functionalization of polymers in pilot scale or in batch processing. On this basis the surface modification step can be adapted into a mass production line of “Lab‐on‐a‐chip” systems.     

Cellular Internalization of Rod‐Like Nanoparticles with Various Surface Patterns: Novel Entry Pathway and Controllable Uptake Capacity

The cellular internalization of rod‐like nanoparticles (NPs) is investigated in a combined experimental and simulation study. These rod‐like nanoparticles with smooth, abacus‐like (i.e., beads‐on‐wires), and helical surface patterns are prepared by the cooperative self‐assembly of poly(γ‐benzyl‐l ‐glutamate)‐block‐poly(ethylene glycol) (PBLG‐b‐PEG) block copolymers and PBLG homopolymers. All three types of NPs can be internalized via endocytosis. Helical NPs exhibit the best endocytic efficacy, followed by smooth NPs and abacus‐like NPs. Coarse‐grained molecular dynamics simulations are used to examine the endocytic efficiency of these NPs. The NPs with helical and abacus‐like surfaces can be endocytosed via novel “standing up” (tip entry) and “gyroscope‐like” (precession) pathways, respectively, which are distinct from the pathway of traditional NPs with smooth surfaces. This finding indicates that the cellular internalization capacity and pathways can be regulated by introducing stripe patterns (helical and abacus‐like) onto the surface of rod‐like NPs. The results of this study may lead to novel applications of biomaterials, such as advanced drug delivery systems.     

Programmed Nanoparticle‐Loaded Nanoparticles for Deep‐Penetrating 3D Cancer Therapy

Tumors are 3D, composed of cellular agglomerations and blood vessels. Therapies involving nanoparticles utilize specific accumulations due to the leaky vascular structures. However, systemically injected nanoparticles are mostly uptaken by cells located on the surfaces of cancer tissues, lacking deep penetration into the core cancer regions. Herein, an unprecedented strategy, described as injecting “nanoparticle‐loaded nanoparticles” to address the long‐lasting problem is reported for effective surface‐to‐core drug delivery in entire 3D tumors. The “nanoparticle‐loaded nanoparticle” is a silica nanoparticle (≈150 nm) with well‐developed, interconnected channels (diameter of ≈30 nm), in which small gold nanoparticles (AuNPs) (≈15 nm) with programmable DNA are located. The nanoparticle (AuNPs)‐loaded nanoparticles (silica): (1) can accumulate in tumors through leaky vascular structures by protecting the inner therapeutic AuNPs during blood circulation, and then (2) allow diffusion of the AuNPs for penetration into the entire surface‐to‐core tumor tissues, and finally (3) release a drug triggered by cancer‐characteristic pH gradients. The hierarchical “nanoparticle‐loaded nanoparticle” can be a rational design for cancer therapies because the outer large nanoparticles are effective in blood circulation and in protection of the therapeutic nanoparticles inside, allowing the loaded small nanoparticles to penetrate deeply into 3D tumors with anticancer drugs.     

Nanomanipulation by Atomic Force Microscopy

The linking of our macroscopic world to the nanoscopic world of single molecules, nanoparticles and functional nanostructures is a technological challenge. Researchers in nanobiotechnology face the questions “How extract and analyze a single nano‐object?”, “How to pick and place nano‐objects?” and “How to prototype a functional nanostructure?”. Here, nanomanipulation by an atomic force microscope (AFM) in combination with optical manipulation by a microbeam laser offers a practicable solution. In such a system, the AFM can be operated as a nanorobot for manipulation purposes allowing for nanometer precision. A contact free manipulation is achieved by the laser microbeam.     

Decoration of surfaces with size-selected clusters and molecular manipulation at room temperature: precision and uncertainty in organizing atoms

The deposition onto surfaces of clusters of atoms, prepared and size-selected in the gas phase, is, like atomic or molecular manipulation with the scanning tunnelling microscope, an appealing (but parallel) route to the creation of nanoscale surface features. Both of these seemingly orthogonal approaches allow, in principle, a selected number of atoms to be organized, and both are strongly affected by the lateral thermal diffusion of the constituent atoms, molecules or clusters over the surface. In this sense, the room-temperature (as opposed to cryogenic-temperature) regime can be regarded as a hostile environment for organizing atoms. In this paper we review recent achievements in size-selected cluster deposition and molecular manipulation at room temperature and thus address the fundamental question: with what precision can we organize atoms at room temperature?     

人工智能艺术设计光晕的持续

对人工智能艺术设计光晕的持续条件标准进行分析。以人工智能艺术家的合法身份与艺术设计作品的标准来探讨,发现了人工智能艺术设计具有持续性的“光晕”。人工智能因机械成为“生产主体”并获得了合法的社会身份,成为了文化智能生产中新的“主体”。智能主体所生产的艺术品已经不单是某种原件的原生命力的再现,在狭义的范畴上,其作品是某个艺术家或设计师观念风格的延续,而在广义的范畴上,是人类文明意识的再造,只有远离糟粕、虚伪、丑恶、异化,才能具有如希腊艺术品一样崇高的膜拜价值和形象的魔力。“真”、“善”、“美”依旧是评价人工智能艺术设计作品是否具有“光晕”的标准。由人工智能生产的作品因其机械性地原创了艺术的物质与观念部分,使其具有了“原真性”,而要想通过“善”赋“魂”,则要在数据和伊始的算法设计上构建“善”的设计约规,形成人文关怀和实现阶层的善用。人工智能艺术设计品是人类精神的集体显现,如同折光镜一般,持续折射人类艺术设计理想的“光晕”。     

Permanent Anticoagulation Blood-Vessel by Mezzo-Sized Double Re-Entrant Structure

Having a permanent omniphobicity on the inner surface of the tube can bring enormous advantages, such as reducing resistance and avoiding precipitation during mass transfer. For example, such a tube can prevent blood clotting when delivering blood composed of complex hydrophilic and lipophilic compounds. However, it is very challenging to fabricate micro and nanostructures inside a tube. To overcome these, a wearability and deformation-free structural omniphobic surface is fabricated. The omniphobic surface can repel liquids by its “air-spring” under the structure, regardless of surface tension. Furthermore, it is not lost an omniphobicity under physical deformation like curved or twisted. By using these properties, omniphobic structures on the inner wall of the tube by the “roll-up” method are fabricated. Fabricated omniphobic tubes still repels liquids, even complex liquids like blood. According to the ex vivo blood tests for medical usage, the tube can reduce thrombus formation by 99%, like the heparin-coated tube. So, the surface will soon replace typical coating-based medical surfaces or anticoagulation blood vessels.     

Co‐Immobilization of Proteins and DNA Origami Nanoplates to Produce High‐Contrast Biomolecular Nanoarrays

The biofunctionalization of nanopatterned surfaces with DNA origami nanostructures is an important topic in nanobiotechnology. An unexplored challenge is, however, to co‐immobilize proteins with DNA origami at pre‐determined substrate sites in high contrast relative to the nontarget areas. The immobilization should, in addition, preferably be achieved on a transparent substrate to allow ultrasensitive optical detection. If successful, specific co‐binding would be a step towards stoichiometrically defined arrays with few to individual protein molecules per site. Here, we successfully immobilize with high specificity positively charged avidin proteins and negatively charged DNA origami nanoplates on 100 nm‐wide carbon nanoislands while suppressing undesired adsorption to surrounding nontarget areas. The arrays on glass slides achieve unprecedented selectivity factors of up to 4000 and allow ultrasensitive fluorescence read‐out. The co‐immobilization onto the nanoislands leads to layered biomolecular architectures, which are functional because bound DNA origami influences the number of capturing sites on the nanopatches for other proteins. The novel hybrid DNA origami‐protein nanoarrays allow the fabrication of versatile research platforms for applications in biosensing, biophysics, and cell biology, and, in addition, represent an important step towards single‐molecule protein arrays.     

Two-Way Random-Effects Analyses and Gauge R&R Studies

An important prerequisite of any sensible data-based engineering study is the quantification of the precision of gauges or measuring equipment to be used in data collection. It has long been understood that in the event that more than one individual will use a particular gauge, “measurement variation” for that gauge can include not only a kind of “pure error” component but an “operator” or “technician” component as well. Furthermore, it is well known that the two-way random-effects model provides a natural framework for quantifying the different components of measurement variation. Some parts of standard practice in the “gauge R&R studies” aimed at quantifying measurement precision, however, are unfortunately at odds with what makes sense under this model. Thus, the purpose of this primarily expository article is to explain in elementary terms the use of a two-way random-effects model for gauge R&R studies, to critique current practice, and to point out some simple improvements that can follow from more careful attention to the model and well-established practice in the general linear model.     

Beschichtung und Reinigung von Oberflächen mit Atmosphärendruck‐Plasmen. Coating and cleaning of surfaces with atmospheric pressure plasmas

Since long time dielectric barrier discharges have been in use for technical applications such as ozone synthesis and surface activation treatment of polymers for subsequent printing, pasting, or laquering. A new field of applications for these discharges is opened by their use for plasma‐based coating and cleaning processes at atmospheric pressure. By introducing gaseous monomers (like hydrocarbons, fluorocarbons, silicon‐organic compounds) into the discharge zone, coatings can be deposited on electrically conductive or insulating substrates. Barrier discharges in oxygen containing gases can also be used for the degreasing of surfaces. Owing to the possibility, to sustain barrier discharges in very small volumes, new perspectives are opened for the geometrically structured modification of chemical and physical properties of surfaces as well as for the modification or coating of internal surfaces in microfluidic devices.     

Calculating fatigue limits of notched components of arbitrary size and shape with cracks growing in mode I

This paper describes the implementation of an alternating technique that uses a short crack growth model in combination with the Finite Element Method (FEM) to calculate fatigue limits. Components of any size and shape can, in principle, be analyzed, but the technique is specially suitable for “small” notched components, i.e., components that are obviously larger than the crack itself but not so large as to allow the adoption or use of infinite-medium solutions and where the “back” surfaces or boundaries of the component (other than the notch itself) may influence the propagation of the fatigue crack. This work represents a first application of the technique and is limited to plane problems where fatigue cracks, for reasons of symmetry, for example, grow in mode I alone. The tool is validated by applying it to several problems of specimens with notches of different forms and sizes. Comparisons with experimental results and with prediction obtained by other methods are presented.     

Solid‐Supported Biomolecules on Modified Silica Surfaces—A Tool for Fast Physicochemical Characterization and High‐Throughput Screening

Biofunctionalization for a wide variety of applications can be achieved by coating silica surfaces with biomolecules such as lipids or proteins. However, specific surface optimization of the inorganic SiO₂ is necessary to achieve biocompatible surfaces. Surface shielded porous silica beads can be non‐covalently coated with a single lipid bilayer. The lipids retain their fluidity in this handy solid‐supported system, perfectly mimicking the soft‐surface properties of cellular membranes. A supramolecular architecture can also be used for functional immobilization of membrane proteins: An artificial cytosolic compartment can be created with the aid of polymers; coating by lipid membranes and integration of membrane proteins results in a solid‐supported biofunctional cellular surface. Another surface modification enables a direct immobilization of human serum albumin (HSA) molecules onto silica surfaces. The HSA on this otherwise passivated surface provides a convenient material for the investigation of unspecific protein binding of pharmaceuticals on a high‐throughput scale.     

EGaIn‐Assisted Room‐Temperature Sintering of Silver Nanoparticles for Stretchable,Inkjet‐Printed,Thin‐Film Electronics

Coating inkjet‐printed traces of silver nanoparticle (AgNP) ink with a thin layer of eutectic gallium indium (EGaIn) increases the electrical conductivity by six‐orders of magnitude and significantly improves tolerance to tensile strain. This enhancement is achieved through a room‐temperature “sintering” process in which the liquid‐phase EGaIn alloy binds the AgNP particles (≈100 nm diameter) to form a continuous conductive trace. Ultrathin and hydrographically transferrable electronics are produced by printing traces with a composition of AgNP‐Ga‐In on a 5 µm‐thick temporary tattoo paper. The printed circuit is flexible enough to remain functional when deformed and can support strains above 80% with modest electromechanical coupling (gauge factor ≈1). These mechanically robust thin‐film circuits are well suited for transfer to highly curved and nondevelopable 3D surfaces as well as skin and other soft deformable substrates. In contrast to other stretchable tattoo‐like electronics, the low‐cost processing steps introduced here eliminate the need for cleanroom fabrication and instead requires only a commercial desktop printer. Most significantly, it enables functionalities like “electronic tattoos” and 3D hydrographic transfer that have not been previously reported with EGaIn or EGaIn‐based biphasic electronics.     

A practice-orientated study of the complex „processing and handling–application–resultant properties”︁ of autopolymerizing PMMA bone cements

Bone cements which are used for the fixation of alloplasties as well as for filling and/or bridging of bone defects had been intensively investigated during the past 15 years. Scientists payed close attention to the subjects of “biocompatibility in view of chemical and thermal effects; polymerization process; structure and properties of bone cements”. As a rule, especially tests for the evaluation of strength properties were carried out with more or less standardized and relatively small specimen. The fund of experience, obtained by the methods mentioned above, don't let us hope to have any further significant progress concerning the transferability of these results to practise. A possible step further in the approximation of model experiments with respect to practical problems in the author's opinion should be the methodically combination of the known single aspects to a larger total complex. As a start in this direction a testing method was developed which enables processing and insertion of bone cements as well as the implantation of endoprostheses-shafts into tubular spaces under similar geometrical and thermal conditions as they are present in big tubular bones. Shape and dimensions of the originated bone cement- “quivers” or “jackets” are chosen in a way that experiments are practicable for the comparison of different types of bone cements and implantating methods as well as the testing of intended or unintended admixtures (for example X-ray contrast agent, antibiotics, blood) with respect to the mechanical loading capacity. Furthermore comparisons with the results of conventional mechanical material testings are possible. The contruction of the testing apparatus and the testing procedure will be presented. Its applicability for tests to compare different types of bone cements with respect to the parameters “processing and insertion method”, “implantating endoprostheses-shafts” and “admixtures” will be discussed by means of obtained results. Finally the question is asced wether a method like this can be an aid for training and objectively valuation of the methodical abilities of budding operating surgeons in this field.     

Fluor‐Kohlenstoff‐Nanoschichten zur gezielten Oberflächenfunktionalisierung. Fluorine‐Carbon Nano Coatings for Specific Surface Functionalization

This article concerns some aspects of the research and development work, which is done within a project of the German Federal Ministry of Education and Research (BMBF) entitled: “nano functionalization of interfaces for data‐, textile‐, building‐, medicine‐, bio‐, and aerospace‐ technology”. In the following the broad field of applications of a surface modification on a nanometer scale is discussed. Also some scientific methods to characterize surface modifications of this kind are discussed. By means of low pressure plasma technology it is possible to functionalize surfaces and thus to well adjust their properties with respect to their application. This is done without changing the bulk material characteristics. The surfaces of the treated workpieces are covered by an ultrathin, i.e. only a few nanometer thick, fluorine‐carbon polymer layer by a plasma process. The physical and chemical surface properties, such as surface energy, roughness (on nanometer scale), dynamic wetting behaviour, or the adhesion properties against other materials, can be simple changed by varying the plasma process parameters. It is shown, that in future this surface modification will meet a broad field of applications.     

Functional Adhesive Surfaces with “Gecko” Effect: The Concept of Contact Splitting

Nature has developed reversibly adhesive surfaces whose stickiness has attracted much research attention over the last decade. The central lesson from nature is that “patterned” or “fibrillar” surfaces can produce higher adhesion forces to flat and rough substrates than smooth surfaces. This paper critically examines the principles behind fibrillar adhesion from a contact mechanics perspective, where much progress has been made in recent years. The benefits derived from “contact splitting” into fibrils are separated into extrinsic/intrinsic contributions from fibril deformation, adaptability to rough surfaces, size effects due to surface‐to‐volume ratio, uniformity of stress distribution, and defect‐controlled adhesion. Another section covers essential considerations for reliable and reproducible adhesion testing, where better standardization is still required. It is argued that, in view of the large number of parameters, a thorough understanding of adhesion effects is required to enable the fabrication of reliable adhesive surfaces based on biological examples.     

Modifizierung organischer Konstruktionswerkstoffe für technische Anwendungen

Modification of Organic Engineering Materials for Technological Applications It is reported about experiments for synthesis of novel reactive, thermotropic, liquid‐crystalline polymers (LCPs) as well as about investigations concerning the use of these LCPs as a blend component for the production of modified polyamide and polyester fibres and their properties. These reactive LCPs are synthetically easy accessible p oly e ster i mid a nhydrides ( PEIA ) bearing lateral as well as terminal anhydride groups. The average number of anhydride groups is variable between 4 and 18. Molecular weights of 30 kg/mol up to 80 kg/mol could be obtained. During mixing of the reactive LC‐PEIAs with polyamide 6 [PA 6] or poly(ethylene terephthalate) [PET] in an extruder under melting conditions both components evidently react within some few minutes to form graft‐block‐copolymers containing on their backbone chains lateral and terminal polyamide respectively polyester blocks. These quickly occurring modification reactions are the base for the industrial application in form of a continuously arrangeable “reactive blending‐spinning‐drawing”‐process. Graft‐block‐copolymers synthesised by this way in the sense of “reactive blending” can be processed together with the corresponding adequate matrix material polyamide 6 or polyester into drawable filaments. After spinning and drawing under suitable conditions lc‐PEIA‐fibrils modified by molecules of the basic polymer with diameters of less than 500 nm are detectable in the resulting filaments. The desired “microphase distribution” of the PA‐modified respectively PET‐modified lc‐PEIA‐macromolecules as the reinforcing system components could be achieved. Moreover these graft‐block‐copolymers built by “reactive blending” in‐situ have a high thermodynamic compatibility because of their chemical similarity to the primary structure of the respective matrix materials resulting in a relatively high reinforcing effect. These both aspects as well as the proceeding orientation of the lc‐PEIA‐microphases by the filament drawing cause, though optimising processes are still remaining, a remarkable increase of the tensile strengths as well as clearly improved initial moduli at a simultaneously raised stretchability of the lc‐PEIA‐modified polyamide and polyester filaments. These effects could be achieved with PEIA‐amounts of lower than 5 percentages by weight .     

Electronic effects on the interfaces “nanodiamond - surface groups – water molecules”

Abstract

In this paper an explanation of the dependence of photoluminescence of detonation nanodiamonds in water on the type of functional surface groups due to the manifestation of inductive and mesomeric electronic effects on the interface “nanodiamond - surface groups – water molecules” is proposed. This explanation based on the experimental results of the study of photoluminescence of detonation nanodiamonds with different surface functionalization and theoretical calculations of the electron density on the surface of nanoparticles. The hypothesis can be extended to other functionalizations of nanodiamonds, which will allow to control the stability and photoluminescent properties of colloidal systems “nanodiamonds-solvent” through the functionalization of the surface of nanoparticles.