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Purpose: The purpose of this study was to investigate efficient methods to evaluate the pigment layer location of tinted soft contact lenses and to assess various lens products on the market using those methods.Methods: Two types of tinted soft contact lenses with known pigment location embedded or back surface were manufactured and examined. Light microscopy (LM), focused ion beam milling and scanning electron microscopy (FIB-SEM), and Fourier-domain optical coherence tomography (FD-OCT) were used to examine the pigment layer. Lens surface roughness was also measured using atomic force microscopy. In the second part of the experiment, pigment location and surface roughness of a clear lens (Lens A) and eight commercially-available tinted soft contact lenses (Lens B-I) were evaluated using FIB-SEM and FD-OCT.Results: Pigment location could be reliably determined with FIB-SEM and FD-OCT. With LM, 40% of the lens sections were broken or deformed during slide preparation. The pigment particles in Lens B were buried below the front surface and there were no significant differences of roughness between the front and back surfaces. However, all tinted lenses with surface pigment had significant difference of roughness between front and back surfaces at the pigmented area.Conclusion: The FIB-SEM and FD-OCT could reliably locate the pigment layer of tinted soft contact lenses. In addition, lens surface roughness was influenced by pigment layer location. [ABSTRACT FROM AUTHOR]

The development of smart delivery systems able to deliver and target a drug to the site of action is one of the major challenges in the field of pharmaceutical technology. The surface modification of nanocarriers, such as liposomes, is widely investigated either for increasing the blood circulation time (by pegylation) or for interacting with specific tissues or cells (by conjugation of a selective ligand as a monoclonal antibody, mAb). Microscopical analysis thereby is a useful approach to evaluate the morphology and the size owing to resolution and versatility in defining either surface modification or the architecture and the internal structure of liposomes. This contribution aims to connect the outputs obtained by transmission electron (TEM) and atomic force (AFM) microscopical techniques for identifying the modifications on the liposomal surface. To reach this objective, we prepared liposomes applying two different pegylation technologies and further modifying the surface by mAb conjugation. This work demonstrates the feasibility to apply the combined approach (TEM and AFM analysis) in the evaluation of the efficacy of a surface engineering process. [ABSTRACT FROM AUTHOR]

The article focuses on the formation of biofilm in anammox bioreactor using microscopic slides. Topics include biofilms morphology, the detection of anammox bacteria in the biofilms by using fluorescent in situ hybridization (FISH), and the assessment of surface microrelief of the biofilms through atomic force microscopy (AFM).

Abstract: The present study was designed to show the applicability of scanning ion conductance microscopy (SICM) for imaging different types of biological samples. For this purpose, we first applied SICM to image collagen fibrils and showed the usefulness of the approach-retract scanning (ARS)/hopping mode for such samples with steep slopes. Comparison of SICM images with those obtained by AFM revealed that the ARS/hopping SICM mode can probe the surface topography of collagen fibrils and chromosomes at nanoscale resolution under liquid conditions. In addition, we successfully imaged cultured HeLa cells, with 15μm in height by ARS/hopping SICM mode. Because SICM can obtain non-contact (or force-free) images, delicate cellular projections were visualized on the surface of the fixed cell. SICM imaging of live HeLa cells further demonstrated its applicability to study the morphological dynamics associated with biological processes on the time scale of minutes under liquid conditions. We further applied SICM for imaging the luminal surface of the trachea and succeeded in visualizing the surface of both ciliated and non-ciliated cells. These SICM images were comparable with those obtained by scanning electron microscopy. Although the dynamic mode of AFM provides better resolution than the ARS/hopping mode of SICM in some samples, only the latter can obtain contact-free images of samples with steep slopes, rendering it an important tool for observing live cells as well as unfixed or fixed soft samples with complicated shapes. Taken together, we demonstrate that SICM imaging, especially using an ARS/hopping mode, is a useful technique with unique capabilities for imaging the three-dimensional topography of a range of biological samples under physiologically relevant aqueous conditions. [Copyright &y& Elsevier]

Abstract: We designed and developed a high-speed atomic force microscope (HSAFM) utilizing a force-feedback scheme for imaging large biological samples. The system collects three simultaneous images: a deflection image, a topographic image, and a force image. We demonstrated that this force-feedback HSAFM is capable of acquiring large topographic images of Escherichia coli biofilms at approximately one frame per second in air. We discuss how the self-actuating cantilever and the piezo tube follow those larger biological topographic features during the HSAFM imaging process. [Copyright &y& Elsevier]

The surface amorphous layer of articular cartilage is of primary importance to its load-bearing and lubrication function. This lipid-filled layer is degraded/disrupted or eliminated when cartilage degenerates due to diseases. This article examines further the characteristic of this surface overlay using a combination of microscopy and imaging methods to evaluate the hypothesis that the surface of articular cartilage can be repaired by exposing degraded cartilage to aqueous synthetic lipid mixtures. The preliminary results demonstrate that it is possible to create a new surface layer of phospholipids on the surface of cartilage following artificial lipid removal, but such a layer does not possess enough mechanical strength for physiological function when created with either unsaturated palmitoyl-oleoyl-phosphatidylcholine or saturated dipalmitoyl-phosphatidylcholine component of joint lipid composition alone. We conclude that this may be due to low structural cohesivity, inadequate time of exposure, and the mix/content of lipid in the incubation environment. [ABSTRACT FROM AUTHOR]

We present the first direct comparison of scanning ion conductance microscopy (SICM) with atomic force microscopy (AFM) for cell imaging. By imaging the same fibroblast or myoblast cell with both technologies in series, we highlight their advantages and disadvantages with respect to cell imaging. The finite imaging force applied to the sample in AFM imaging results in a coupling of mechanical sample properties into the measured sample topography. For soft samples such as cells this leads to artifacts in the measured topography and to elastic deformation, which we demonstrate by imaging whole fixed cells and cell extensions at high resolution. SICM imaging, on the other hand, has a noncontact character and can provide the true topography of soft samples at a comparable resolution. [ABSTRACT FROM AUTHOR]

High-resolution microscopy techniques provide a plethora of information on biological structures from the cellular level down to the molecular level. In this review, we present the unique capabilities of transmission electron and atomic force microscopy to assess the structure, oligomeric state, function and dynamics of channel and transport proteins in their native environment, the lipid bilayer. Most importantly, membrane proteins can be visualized in the frozen-hydrated state and in buffer solution by cryo-transmission electron and atomic force microscopy, respectively. We also illustrate the potential of the scintillation proximity assay to study substrate binding of detergent-solubilized transporters prior to crystallization and structural characterization. [ABSTRACT FROM AUTHOR]

The development of atomic force microscopy has evolved into a wide variety of microscopy and characterization techniques well beyond conventional imaging. The focus of this review is on characterization methods based on the scanning probe and their application in characterizing physical properties of soft materials. This consideration is broken into three major categories focusing on mechanical, thermal, and electrical/magnetic properties in addition to a brief review of high-resolution imaging. Surface spectroscopy is discussed to great extent and consideration includes procedural information, common pitfalls, capabilities, and their practical application in characterizing soft matter. Key examples of the method are presented to communicate the capabilities and impact that probe-based characterization techniques have had on the mechanical, thermal, and electrical characterization of soft materials. [ABSTRACT FROM AUTHOR]

Abstract: Chemical force microscopy (CFM) is an extension of atomic force microscopy (AFM) that employs a chemically-functionalized tip, which makes it possible to control chemical interactions between tip and sample, so CFM can be used to probe local chemical information on the surfaces of materials and biological samples under near-native environments at nanoscale spatial resolution. We describe applications of CFM for materials characterization, including measurements of single intermolecular interaction forces and investigations of nanoscale heterogeneity of surface-chemical properties of polymeric materials. [Copyright &y& Elsevier]

Bottom-up assembly at the level of individual molecules requires a combination of utmost spatial precision and efficient monitoring. We have previously shown how to ‘cut-and-paste’ single molecules, and other groups have demonstrated that it is possible to beat the diffraction limit in optical microscopy. Here we show that a combination of single-molecule cut-and-paste surface assembly, total internal reflection fluorescence microscopy and atomic force microscopy can be used to deposit individual fluorophores in well-defined nanoscale patterns and also to monitor the process in real time with nanometre precision. Although the size of the pattern is well below the optical resolution of the microscope, the individual dyes are identified by localizing the centroids and detecting the photobleaching of the fluorophores. With this combination of methods, individual dyes or labelled biomolecules can be arranged at will for specific functions, such as coupled fluorophore systems or tailored enzyme cascades, and monitored with nanoscale precision. [ABSTRACT FROM AUTHOR]

Simultaneous structural and chemical characterization of materials at the nanoscale is both an immediate need and an ongoing challenge. This article reports a route to address this need, which can be rapidly adopted by practitioners, by combining the benefits of widely available scanning probe microscopy and vibrational microspectrometry. In an atomic force microscope (AFM), the probe tip can provide a nanoscale topographic image. Here, we use a temperature-controlled probe tip to selectively acquire an analyte from a specified location and determine its mass in a thermogravimetric manner. The tip is then analyzed via complementary Raman and Fourier transform infrared microspectrometers, providing a molecular characterization of samples down to the femtogram level in minutes. The probe can be self-cleaned and employed for repeated use by rapidly heating it to vaporize the analyte. By combining the established analytical modalities of AFM and vibrational spectrometry, a complete physical and molecular characterization of nanoscale domains is possible: mass determination is facile, thermal analyses can be integrated on the probe, and the obtained spectral data can be related to existing knowledge bases. [ABSTRACT FROM AUTHOR]

Microdomains in SBN-0.61 polydomain crystals have been recorded by the atomic force microscopy method with the application of a dc voltage of 1–10 V applied to a probe. The domain areas have been obtained as functions of the voltage and exposition time. The kinetics of the decay of the domains after the shutdown of the field have been determined. The nonclassical characteristics observed in the dynamics of domain walls are attributed to the nonuniform spatial distribution of the atomic force microscope field. The kinetics of the decay of the microdomains are in qualitative agreement with the kinetics of the depolarization of the strontium-barium niobate solutions, which is observed by macroscopic methods. [ABSTRACT FROM AUTHOR]

Progress in understanding the structure–function relationships of the mycobacterial cell wall has been hampered by its complex architecture as well as by the lack of sensitive, high-resolution probing techniques. For the first time, we used atomic force microscopy (AFM) to image the surface topography of hydrated Mycobacterium bovis bacillus Calmette Guérin cells and to investigate the influence of the antimycobacterial drug ethambutol on the cell wall architecture. While untreated cells showed a very smooth and homogeneous surface morphology, incubation of cells in the presence of ethambutol caused dramatic changes of the fine surface structure. At 4 μg mL−1, the drug created concentric striations at the cell surface and disrupted a ∼8 nm thick cell wall layer, attributed to the outer electron-opaque layer usually seen by electron microscopy, while at 10 μg mL−1 an underlying ∼12 nm thick layer reflecting the thick electron-transparent layer was also altered. These noninvasive ultrastructural investigations provide novel information on the macromolecular architecture of the mycobacterial envelope as well as into the destructuring effects of ethambutol. [ABSTRACT FROM AUTHOR]

We show a new atomic force microscopy technique for obtaining high-resolution topographic images of large bio-samples. To obtain high-resolution topographic images for the samples, we fabricated a long polymeric tip with a small protrusion using two-photon adsorbed photo-polymerization techniques. The obtained tip length was over 50 µm, and the tip was used directly to visualize COS-1 and 293 cells. Compared with commercial tips, the long tip made it easier to obtain topographic images of the large cells. In the magnified topographic images, the sub-100-nm resolution was confirmed with the long tips. This long probe tip is expected to broaden large sample-related studies and applications in the future. [ABSTRACT FROM AUTHOR]

We report the simultaneous in situ electrochemical, optical, and surface morphological studies of conjugated polymer ultrathin film formation using a novel combined electrochemical instrumentation–surface plasmon resonance spectroscopy–atomic force microscopy. The initial stages of the electropolymerization of poly(3,4-ethylenedioxythiophene) films on flat gold electrode/substrates were observed in all three experiments simultaneously. In addition to the electrochemical information obtained, the surface plasmon optical technique showed the deposition of the film, and provided electrochromic behavior of the deposited film. Simultaneously, atomic force microscopy gave surface morphological properties and domain growth of the film. The complementarity of the information obtained from the combined techniques is useful for the investigation of polymer growth mechanism between cyclic voltammetry and potentiostatic deposition methods. [ABSTRACT FROM AUTHOR]

Scanning probe microscopy is now an accepted tool in both industrial and research efforts. Its development parallels the advances in technology and imaging applications found in the history of progress of both transmission electron microscopy and scanning electron microscopy. All three forms of microscopy ultimately suffer a fundamental application problem—situations arise where it is either unreasonable or impossible to observe a particular sample within the sample stage of the microscope. For the transmission and electron and scanning electron microscopies, this problem has been resolved by resorting to making a replica of the area of interest on the actual sample and preparing the replica so that it may be imaged directly by the desired microscopy technique. This work attempts to ascertain the suitability of observing replicas using a scanned probe microscope; specifically, employing the techniques of atomic force microscopy to image plastic surface replicas. [ABSTRACT FROM AUTHOR]

Recent advances in the development of new microscopy techniques with a sensitivity of a single molecule have gained access to essentially new types of information obtainable from imaging biomolecular samples. These methodologies are analysed here in terms of their applicability to the in vivo visualization of cellular processes on the molecular scale, in particular of processes in cell membranes. First examples of single molecule microscopy on cell membranes revealed new basic insight into the lateral organization of the plasma membrane, providing the captivating perspective of an ultrasensitive methodology as a general tool to study local processes and heterogeneities in living cells. [ABSTRACT FROM AUTHOR]

Atomic force microscopy (AFM) was used to observe particle shape and surface texture details of normal portland cement and supplementary cementing materials (silica fume, low-calcium fly ash, and high-calcium fly ash). The latter materials mixed with cement were examined after prolonged hydration. Significant innovative information on particle shape and hydrated paste microstructure was obtained. Conventional microscopy techniques, such as scanning electron microscopy (SEM), cannot provide such detailed images and surface texture characteristics of the fine materials (especially silica fume) and of the product microstructure. AFM showed, for the first time, that silica fume particles are primarily composed of two complimentary parts (hemispheres or semicylinders). Nano-size particles were found in all materials. A relatively smooth product surface was observed in the hydrated cement paste. The hydrated surface of the addition-cement pastes presented small spheroid bulges, giving an additional roughness as was measured by AFM. A sufficient correlation of this microscopical quantitative information with macroscopical engineering and durability properties of cement products is also presented. [ABSTRACT FROM AUTHOR]

Efficient characterization of the physicochemical attributes of bioactive-loaded micro/nano-vehicles is crucial for the successful product development. The introduction of outstanding science-based strategies and techniques makes it possible to realize how the characteristics of the formulation ingredients affect the structural and (bio)functional properties of the final bioactive-loaded carriers. The important points to be solved, at a microscopic level, are investigating how the features of the formulation ingredients affect the morphology, surface, size, dispersity, as well as the particulate interactions within bioactive-comprising nano/micro-delivery systems. This review presents a detailed description concerning the application of advanced microscopy techniques, i.e., confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) in characterizing the attributes of nano/microcarriers for the efficient delivery of bioactive compounds. Furthermore, the fundamental principles of these approaches, instrumentation, specific applications, and the strategy to choose the most proper technique for different carriers has been discussed. Unlabelled Image • Development of micro/nanocarriers for the delivery of bioactives is currently expanding. • Characterization of the attributes of bioactive-loaded micro/nano-vehicles is very crucial. • This review focuses on the application of advanced microscopy techniques in this field. • Applying these sophisticated approaches is a key for the development of practical carriers. [ABSTRACT FROM AUTHOR]

Atomic force microscopy (AFM) is one of the frequently used microscopy techniques to capture high-resolution images in science and engineering. Since the spatial resolution limit of AFM has been mostly reached and no further improvement is likely, much of the recent attention in the development of new AFM has been on improvement of speed. We present a photo-thermal, high-speed atomic force microscope scan head capable of exciting cantilevers photo-thermally and detecting cantilever motions with an optical beam bounce technique. The design features a unique Z-collar that permits direct mounting of a Z-scanner onto a microscope objective lens to achieve a high mechanical bandwidth. We demonstrate the performance of the developed scan head by imaging data tracks of a Blu-ray disk in tapping and contact modes. [ABSTRACT FROM AUTHOR]

A new sample holder that allows combined microtomy for atomic force microscopy (AFM) and transmission electron microscopy (TEM) is described. The main feature of this sample holder is a small central part holding the sample. This central part fits into the head of an atomic force microscope. AFM measurements can be performed with a sample mounted in this central part of the sample holder. This makes the alignment of a microtomed bulk sample unnecessary, and offers the opportunity of an easy and fast combined sample preparation for AFM and TEM. [ABSTRACT FROM AUTHOR]