Search

In vivo optical trapping is a novel applied direction of an optical manipulation, which enables one to noninvasive measurement of mechanical properties of cells and tissues in living animals directly. But an application area of this direction is limited because strong scattering of many biological tissues. An optical clearing enables one to decrease the scattering and therefore increase a depth of light penetration, decrease a distortion of light beam, improve a resolution in imaging applications. Now novel methods had appeared for a measurement an optical clearing degree at a cellular level. But these methods aren’t applicable in vivo. In this paper we present novel measurement method of estimate of the optical clearing, which are based on a measurement of optical trap stiffness. Our method may be applicable in vivo.

Traumatic brain injury (TBI) represents a major treatment challenge in both civilian and military medicine; on the cellular level, its mechanisms are poorly understood. As a method to study the dysfunctional repair mechanisms following injury, laser induced shock waves (LIS) are a useful way to create highly precise, well characterized mechanical forces. We present a simple model for TBI using laser induced shock waves as a model for damage. Our objective is to develop an understanding of the processes responsible for neuronal death, the ways in which we can manipulate these processes to improve cell survival and repair, and the importance of these processes at different levels of biological organization. The physics of shock wave creation has been modeled and can be used to calculate forces acting on individual neurons. By ensuring that the impulse is in the same regime as that occurring in practical TBI, the LIS model can ensure that in vitro conditions and damage are similar to those experienced in TBI. This model will allow for the study of the biochemical response of neurons to mechanical stresses, and can be combined with microfluidic systems for cell growth in order to better isolate areas of damage.

This paper presents the design and realization of a compact, portable and cost effective microfluidic system for isolation and detection of rare circulating tumor cells (CTCs) in suspension. The innovative aspect of the proposed isolation method is that it utilizes superparamagnetic particles (SMPs) to label CTCs and then isolate those using microtraps with integrated current carrying microconductors. The magnetically labeled and trapped CTCs can then be detected by integrated magnetic microsensors e.g. giant magnetoresistive (GMR) or giant magnetoimpedance (GMI) sensors. The channel and trap dimensions are optimized to protect the cells from shear stress and achieve high trapping efficiency. These intact single CTCs can then be used for additional analysis, testing and patient specific drug screening. Being able to analyze the CTCs metastasis-driving capabilities on the single cell level is considered of great importance for developing patient specific therapies. Experiments showed that it is possible to capture single labeled cells in multiple microtraps and hold them there without permanent electric current and magnetic field.

Average lifetime between the usually bi-exponential double -label specimen and a mono -exponential single donor sample serves as a basis for the calculation of the average energy transfer efficiency (E ). T his semi-quantitative approach however does not fully explore cellular functions, such as endosomal pH differences, specific morphological features, ex amin ing sub-po pulations and the like. W e applied a different, quantitative Regi on -of-Interest (ROI)-based method in 2 live -cell assays by TCSPC FLIM-FRET microscopy: a 5 amino-acid linked FRET standard and mouse pituitary cells expressing a GLPHUL]HG& (%3. -bZip transcription factor in the nucleus , both tagged with Cerulean (C) and Venus (V). ROIs with different selection thresholds were generated and compared. Average lifetimes are similar , but ratios between them and other subtle differences are revealed by compreh ensive distribution information. Following published references, we also explored 3 different methods to calculate FLIM-FRET energy transfer efficiencies for the Cerulean-Venus constructs, producing differences and supporting the long-held notion that is called 'apparent' E . efficiencyFRET's greatest contribution es to be exploringcontinu changes taking place at the cellular level and quantifying differences in relative terms between control and variables .

MicroRNAs (miRNAs) participate in the significant processes of life course, can be used as quantificational biomarkers for cellular level researches and related diseases. Conventional methods of miRNAs’ quantitative detection are obsessed with low sensitivity, time and labour consuming. Otherwise, the emerging miRNAs detection approaches are mostly exposed to the expensive equipment demands and the professional operation, remains at the stage of laboratory and concept demonstration phase. Herein, we designed a novel miRNAs detection platform that based on enzyme-free DNA circuits and electrochemical luminescence (ECL). MicroRNA21 was chosen as the ideal analyte of this platform. The whole process consists of enzyme-free DNA circuits and ECL signal giving-out steps, achieves advantages of operating in constant temperature condition, without the participation of the enzyme, preferable sensitivity and specificity. Through this approach, the sensitivity achieved at 10pM. It is indicated that this miRNAs detection platform possesses potentials to be an innovation of miRNA detection technologies in routine tests. Benefits of the high penetration of ECL in well-equipped medical establishment, this approach could greatly lessen the obstacles in process of popularization and possess excellent prospects of practical application.

M ethods of s -LASCA and t -LASCA have been adopted to pr oblem of monitoring growth of colonies of bacteria E . coli culture B6 . Set -up of LASCA -microscope is developed. Results of experimental investigations of influence of speckled biospeckles on results of monitoring of growth of bacterial colonies have been obtained. Keywords: LASCA, bacterial colony, E. coli 1. INTRODUCTION Such method of Laser Speckle Contrast Analysis (LASCA) 1,2 have been proposed for more than 15 years ago . Previously, this method has been used to diagnosis of blood flow in norm and at some patho logical changes 3,4,5 , for monitoring of growing of malignant tumor, to testing the toxicity of the new -generation vaccine against very dangerous diseases 6 , and in studying the hydrodynamic of microflow in isolated blood vessel in mesentery of white rats 7 . In recent years, some papers devoted to study of structure of bacterial colonies and their identification, have been published. But, to the knowledge of the authors of this paper, no effort has been made to implement LASCA method to control the gro wth in bacterial colony. This paper partially fills this gap. The main goal of this article is an adaptation of the methods of s-LASCA and t-LASCA to problem of monitoring changes in structure of growing colon y of bacteria and development of new type o f biosensors of cellular level of organization.

Ensuring 25-year reliability of a CPV system requires knowledge of potential failure modes and material deficiencies. While Emcore’s CPV system conforms to all IEC 62108 tests, additional tests to eliminate potential long term reliability concerns have been performed. Performance is evaluated through all levels of integration, from cell to module. Tests at the cell level include IEC 62108 tests where feasible, as well as several other tests to establish the ability of the cell to survive additional integration and perform well throughout the lifetime of the CPV module. At a receiver assembly and module level, potential reliability concerns are addressed through targeted testing, which consists of accelerated stress tests which are used to quickly evaluate material performance and designed stress tests which allow the determination of activation energies. With this information, expected lifetime can be assessed and reliability concerns mitigated. Test methodologies and results from cell, receiver assembly and full module are presented demonstrating that targeted stress testing at each level of integration is a viable approach to assessing potential CPV failure modes.

Conducting polymers such as polypyrrole are well-known for their volume changing capacity and their use as actuating material. Actuators based on polypyrrole have been demonstrated in dimensions ranging from centimetres down to micrometres as well as in linear strain and bending beam actuation modes. The polypyrrole (micro-)actuators can be operated in salt solutions including cell culture media and blood. In addition, polypyrrole is known to be biocompatible making them a good choice for applications within cell biology and medicine. Applications of polypyrrole actuators within micromechanical devices, such as microrobotics and valves, will be presented. Opportunities and devices for the medical device industry, especially vascular surgery will be shown. This includes a rotating PCTA balloon system, a steerable guide wire, and an implantable drug delivery system. In addition, novel mechanostimulation chips for cell biology will be introduced. Using these devices, we can stretch cells and show the cellular response to this mechanical stimulation. Since the dawn of eukaryotic cells many parallel molecular mechanisms that respond to mechanical stimuli have evolved. This technology allows us to begin the investigation of these mechanisms on a single cell level.

Imaging in general is becoming increasingly important in the medical science. At the cell level it is possible to label and trace almost individual molecules in vivo to study biochemical reactions ...

In order to go through the transition term from GDSII to OASIS successfully, the aid of the verification tools between OASIS and GDSII is necessary. In general, we have two methods of OASIS file verification. One is a hierarchical method that checks between GDSII and OASIS by each cell level. The other is a flat method that merges each pattern through its hierarchy into a flat level and compares the flattened geometry one by one. We did the experiments of comparison between two methods for OASIS to GDSII verification. The software tool called 'ogdiff' has been used for a hierarchical verification experiment. We used SmartMRC for the flat method experiment. In this paper, we show the experimental results of comparison and we also address the pros and cons of each method. Then we suggest which method is preferable for specific cases.

We report on the development of a Forster resonance energy transfer (FRET) enabled atomic force microscope (AFM) for the study of biomechanics and mechanobiology at the cellular level. The hybrid microscopy system combines the spatial resolution and control of the AFM with the nanoscale sensing capabilities of FRET to enable simultaneous detection of cell mechanical responses and correlation of those responses with cellular biochemistry. Here, we show FRET signal from donor-coated microspheres, that are attached to an AFM cantilever, to acceptor-labeled integrins in a fixed cell system. Additionally, we demonstrate and discuss the attachment of quantum dots to silica microspheres as the FRET donor.

There have been numerous reports describing the phenomena of low-level light therapy (LLLT) within the clinic and its broad application to alleviate pain, enhance the rate of wound healing, including spinal cord injury, reduce inflammation, improve learning, bolster immunity and combat disease. Yet, despite the breadth of potential applications for which bio-stimulation may prove beneficial, there persists a dramatic ignorance in our understanding of the signal pathways that govern these effects. At the cellular level, there exist a variety of endogenous chromophores such as cytochrome C oxidase, NADPH, FAD, FMN and other factors intrinsic to the electron transport chain in mitochondria that absorb light of specific wavelength and will undoubtedly have their role in bio-stimulation, however the dose dependency of effect with regard to total light fluence and fluence rate, as well as the importance of specific subcellular targeting, remains elusive. Furthermore, the translation of cellular response(s) in vitro to in vivo needs to be expounded. Clearly, a rigorous examination of bio-stimulatory parameters as a function of cellular and tissue response is necessary if we are to attain optimized, reproducible protocols based on a true scientific rationale for using bio-stimulation as a therapeutic modality in clinic. This paper introduces a number of the challenges we now face for advancing the bio-stimulation phenomena into the scientific mainstream by highlighting our current knowledge in this field as well as some of the research that we are conducting using LLLT in combination with photodynamic therapy.

In the past decade, optical coherence tomography (OCT) has achieved a rapid development in clinical applications. Its capability of on-line measurement, non-destructive manner and high spatial resolution offers a great potential for tissue engineering in which the dynamic process of tissue growth need to be monitored on-line either for bulk constructs or at the cellular level. In this study, two OCT systems, time-domain Michelson interferometer based OCT (TD-OCT) and whole field OCT (WF-OCT) have been used to image poly(lactic acid) based scaffold and tissue engineered bone. It is demonstrated that TD-OCT is able to visualize the porous structure of the scaffold and its changes during culture at a macroscopic level, whilst the cells' distribution and morphology can be depicted clearly in WF-OCT. With the aid of an external contrast agent, magnetic beads, clearer cellular images have been obtained.

Selective tissue damage on the cellular level can be achieved due to microbubble formation around laser heated intracellular pigments. To get an estimate on damage ranges we investigated microbubble dynamics (lifetime, size) around isolated melanosomes of the retinal pigment epithelium in aqueous suspensions by fast flash photography and probe laser transmission. For short pulsed laser irradiation (12ns@532nm) an increasing radiant exposure results in larger bubble sizes. Bubble diameters ranging from 1 μm to 10 μm were observed. Applying longer pulses (1.8μs@527nm), increasing radiant exposure leads to an earlier onset of bubble growth relative to the pulse. In this case, the diameter of the bubble is nearly independent of the radiant exposure, whereas the number of bubbles during the pulse increases towards higher radiant exposures.

Laser beam of appropriate wavelength affecting living tissue can stimulate different processes on cell level. If laser beam power is less than about 500 mW no photothermal effects take place in the target tissue. The aim of the experimental studies was to determine whether and how the biostimulation laser beam chan change electrical activity or ear cochlea at guinea pigs. Experiment was performed on 10 pigmented animals. Very different responses of cochlea on laser expose have been recorded. Lack of answer of cochlea on the laser irradiation was observed in 20% of examined cases.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The EMPHO SSK is a scanning micro ligbtguide spectrophotometer constructed for 3D-imaging in all tissues of humansand mammals. By monitoring of intracapillary hemoglobin oxygenation and concentration very precise information of themicrocosm (1 mm3) of the oxygen supply level of tissues can be gained. Measurements in skin and liver revealed that on the basis of numeric data obtained by optical remission techniques 3D-images can be constructed which provide information on functional structures of intact organs. KEYWORDS Functional structures ofHbO2fHb, 3D-structures in tissue, monitoring in human skin, EMPHO SSK Oxyscan 1. INTRODUCTION In organs ofhumans and mammals heterogeneities ofmost parameters are found on the capillary and cellular level which are caused by pressure and diffusion gradient fields. The principal shapes of these structures of gradients cannot be visualized by statistical analysis of the different tissue parameters. However, all such gradient fields become only visiblefor the perception system of our brain when the highly dynamic spatial structures are transformed into three-dimensionalstructures.A very instructive and interesting example of modeling dynamic structures of tissue is the 3D-imaging of intracapillary

A technology capable of imaging tissue, at or near the cellular level, could lead to the detection of neoplasias at earlier stages than currently possible. This could significantly improve patient outcomes, since once cancer becomes metastatic, cure is difficult. Optical coherence tomography (OCT), a recently developed imaging technology, has ben shown to achieve resolution in the cellular and subcellular range, and it could improve the diagnostic range of clinical imaging procedures. To assess the clinical applicability of OCT, neoplastic specimens from the urinary, gastrointestinal and female reproductive tract were imaged. Sharp differentiation of structures included the mucosa/submucosal/muscularis boundaries, epithelium, glands, supportive tissue, and intramural cysts. The ability of optical coherence tomography to image tissue microstructure at or near the cellular level make it a potentially powerful technology for minimally invasive assessment of tissue microstructure. The resolution of optical coherence tomography, which is greater than any current clinical imaging modality, make it particularly attractive for the assessment of early neoplastic changes.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Hematoporphyrin-Derivative (HpD) is a photodynamic drug increasingly used in tumor photo-therapy. The chemical and biological bases of its tumor specificity are yet to be clarified. In this paper we present the results of fluorometric studies of HpD both at the cellular level and in solution, including time-resolved fluorescence measurements. The results of these studies were correlated with the effects of HpD observed in cells.