scholarly journals Optimization of Optical Trapping and Laser Interferometry in Biological Cells

2020 ◽  
Vol 10 (14) ◽  
pp. 4970
Author(s):  
Yujiro Sugino ◽  
Masahiro Ikenaga ◽  
Daisuke Mizuno

Optical trapping and laser interferometry enable the non-invasive manipulation of colloids, which can be used to investigate the microscopic mechanics of surrounding media or bound macromolecules. For efficient trapping and precise tracking, the sample media must ideally be homogeneous and quiescent whereas such conditions are usually not satisfied in vivo in living cells. In order to investigate mechanics of the living-cell interior, we introduced (1) the in-situ calibration of optical trapping and laser interferometry, and (2) 3-D feedback control of a sample stage to stably track a colloidal particle. Investigating systematic errors that appear owing to sample heterogeneity and focal offsets of a trapping laser relative to the colloidal probe, we provide several important caveats for conducting precise optical micromanipulation in living cells. On the basis of this study, we further improved the performance of the techniques to be used in cells, by optimizing the position sensitivity of laser interferometry and the stability of the feedback simultaneously.

Author(s):  
C.N. Airriess ◽  
B.R. McMahon ◽  
I.J. McGaw ◽  
G.B. Bourne

The pulsed-Doppler flowmeter permits continuous, non-invasive measurement of blood flow through several arteries simultaneously. Summation of volume flow rates through all arteries leaving the heart allows determination of cardiac output, stroke volume, and the percentage of cardiac output delivered to each region of the body. The use of this system for investigating changes in arterial perfusion as well as its calibration in situ are described.


1999 ◽  
Vol 81 (3) ◽  
pp. 520-527 ◽  
Author(s):  
G J Czarnota ◽  
M C Kolios ◽  
J Abraham ◽  
M Portnoy ◽  
F P Ottensmeyer ◽  
...  

2020 ◽  
Author(s):  
Alec N. Thomas ◽  
Kang-Ho Song ◽  
Awaneesh Upadhyay ◽  
Virginie Papadopoulou ◽  
David Ramirez ◽  
...  

AbstractNanodrops comprising a perfluorocarbon liquid core can be acoustically vaporized into echogenic microbubbles for ultrasound imaging. Packaging the microbubble in its condensed liquid state provides distinct advantages, including in situ activation of the acoustic signal, longer circulation persistence, and the advent of expanded diagnostic and therapeutic applications in pathologies which exhibit compromised vasculature. One obstacle to clinical translation is the inability of the limited surfactant present on the nanodrop to encapsulate the greatly expanded microbubble interface, resulting in ephemeral microbubbles with limited utility. In this study, we examine a biomimetic approach to stabilizing an expanding gas surface by employing the lung surfactant replacement, Beractant. Lung surfactant contains a suite of lipids and surfactant proteins that provides efficient shuttling of material from bilayer folds to the monolayer surface. We therefore hypothesized that Beractant would improve stability of acoustically vaporized microbubbles. To test this hypothesis, we characterized Beractant surface dilation mechanics and revealed a novel biophysical phenomenon of rapid interfacial melting, spreading and re-solidification. We then harnessed this unique spreading capability to increase the stability and echogenicity of microbubbles produced after acoustic droplet vaporization for in vivo ultrasound imaging. Such biomimetic lung surfactant-stabilized nanodrops may be useful for applications in ultrasound imaging and therapy.Graphical Abstract


Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 996 ◽  
Author(s):  
Suset Barroso-Solares ◽  
Paula Cimavilla-Roman ◽  
Miguel Angel Rodriguez-Perez ◽  
Javier Pinto

The use of polymeric nanocomposites has arisen as a promising solution to take advantage of the properties of nanoparticles (NPs) in diverse applications (e.g., water treatment, catalysis), while overcoming the drawbacks of free-standing nanoparticles (e.g., aggregation or accidental release). In most of the cases, the amount and size of the NPs will affect the stability of the composite as well as their performance. Therefore, a detailed characterization of the NPs present on the nanocomposites, including their quantification, is of vital importance for the optimization of these systems. However, the determination of the NPs load is often carried out by destructive techniques such as TGA or ICP-OES, the development of non-invasive approaches to that aim being necessary. In this work, the amount of silver NPs synthesized directly on the surface of melamine (ME) foams is studied using two non-invasive approaches: colorimetry and X-ray radiography. The obtained results show that the amount of silver NPs can be successfully determined from the luminosity and global color changes of the surface of the foams, as well as from the X-ray attenuance.


Epigenomics ◽  
2020 ◽  
Vol 12 (15) ◽  
pp. 1257-1271
Author(s):  
Rongjun Cui ◽  
Chi Liu ◽  
Ping Lin ◽  
Hui Xie ◽  
Wei Wang ◽  
...  

Aim: To investigate the role and mechanisms of AC245100.4 in prostate cancer. Materials & methods: The expression and location of AC245100.4 were examined using real-time PCR and  in situ hybridization. Cell Counting Kit-8, clone formation, flow cytometry and in vivo assays were conducted to determine the role of AC245100.4. RNA antisense purification with mass spectrometry and RNA immunoprecipitation were performed to identify proteins that bind to AC245100.4. Western blotting was performed to quantify the expression of protein. Results: AC245100.4 expression was upregulated in prostate cancer and mainly located in the cytoplasm. Knockdown of AC245100.4 inhibited proliferation of prostate cancer. Mechanistically, AC245100.4 bound to HSP90 and altered its chaperone function, increased the stability of IκB kinase and activated the NFκB signaling pathway. Conclusion: AC245100.4 promotes the proliferation of prostate cancer via binding of HSP90.


2019 ◽  
Vol 55 (1) ◽  
pp. 27-30 ◽  
Author(s):  
Yufu Tang ◽  
Yuanyuan Li ◽  
Zhen Wang ◽  
Feng Pei ◽  
Xiaoming Hu ◽  
...  

A nitric-oxide-activatable organic semiconducting nanoprobe was developed forin vivo,in situ, real-time and non-invasive NIR-II fluorescence monitoring of drug-dose-dependent hepatotoxicity.


2005 ◽  
Vol 62 (2) ◽  
pp. 293-299 ◽  
Author(s):  
Harold M. Swartz ◽  
Akinori Iwasaki ◽  
Tadeusz Walczak ◽  
Eugene Demidenko ◽  
Ildar Salikov ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Octavio López-Albors ◽  
Pedro José Llamas-López ◽  
Joaquín Ángel Ortuño ◽  
Rafael Latorre ◽  
Francisco Alberto García-Vázquez

AbstractThe pH–CO2–HCO3− system is a ubiquitous biological regulator with important functional implications for reproduction. Knowledge of the physiological values of its components is relevant for reproductive biology and the optimization of Assisted Reproductive Technologies (ARTs). However, in situ measurements of these parameters in the uterus are scarce or null. This study describes a non-invasive method for in situ time-lapse recording of pH and CO2 within the uterus of non-anesthetized sows. Animals were at three different reproductive conditions, estrous with no insemination and two hours after insemination, and diestrous. From pH and CO2 data, HCO3− concentration was estimated. The non-invasive approach to the porcine uterus with novel optical probes allowed the obtaining of in situ physiological values of pH, CO2, and HCO3−. Variable oscillatory patterns of pH, CO2 and HCO3− were found independently of the estrous condition. Insemination did not immediately change the levels of uterine pH, CO2 (%) and HCO3− concentration, but all the values were affected by the estrous cycle decreasing significantly at diestrous condition. This study contributes to a better understanding of the in vivo regulation of the pH-CO2-HCO3− system in the uterus and may help to optimize the protocols of sperm treatment for in vitro fertilization.


1997 ◽  
Vol 41 (2) ◽  
pp. 445-448 ◽  
Author(s):  
N Ruiz-Balaguer ◽  
A Nacher ◽  
V G Casabo ◽  
M Merino

Cefuroxime is commercially available for parenteral administration as a sodium salt and for oral administration as cefuroxime axetil, the 1-(acetoxy)ethyl ester of the drug. Cefuroxime axetil is a prodrug of cefuroxime and has little, if any, antibacterial activity until hydrolyzed in vivo to cefuroxime. In this study, the absorption of cefuroxime axetil in the small intestines of anesthetized rats was investigated in situ, by perfusion at four concentrations (11.8, 5, 118 and 200 microM). Oral absorption of cefuroxime axetil can apparently be described as a specialized transport mechanism which obeys Michaelis-Menten kinetics. Parameters characterizing absorption of prodrug in free solution were obtained: maximum rate of absorption (Vmax) = 289.08 +/- 46.26 microM h-1, and Km = 162.77 +/- 31.17 microM. Cefuroxime axetil transport was significantly reduced in the presence of the enzymatic inhibitor sodium azide. On the other hand, the prodrug was metabolized in the gut wall through contact with membrane-bound enzymes in the brush border membrane before absorption occurred. This process reduces the prodrug fraction directly available for absorption. From a bioavailability point of view, therefore, the effects mentioned above can explain the variable and poor bioavailability following oral administration of cefuroxime axetil. Thus, future strategies in oral cefuroxime axetil absorption should focus on increasing the stability of the prodrug in the intestine by modifying the prodrug structure and/or targeting the compound to the absorption site.


2020 ◽  
Author(s):  
Octavio López Albors ◽  
Pedro José Llamas-López ◽  
Joaquín Ortuño ◽  
Rafael Latorre ◽  
Francisco Alberto García Vázquez

Abstract Background The pH-CO2-HCO3− system is a ubiquitous biological regulator with important functional implications for reproduction. Knowledge of the physiological values of its components is relevant for reproductive biology and the optimization of Assistant Reproductive Techniques (ARTs). In vivo pH of the oviduct and uterus has been estimated by direct in situ measurements in a few species. However, regarding the levels of CO2 and HCO3−, information is very scarce and, when available, it comes from fluid samples instead of in vivo estimations. This study describes a non-invasive method to measure pH and % of CO2 in the uterus of sows with cutting-edge technology and no medication. Sows were at three different reproductive conditions, estrous with no insemination E(-)AI and after insemination E(+)AI, and diestrous (non-estrous, NE). From pH and CO2 data, HCO3− concentration was estimated. Results The designed methodology allowed for in situ time-lapse recording of pH and % of CO2 within the uterus of non-anesthetized sows. Variable oscillatory patterns of pH, CO2 and HCO3− were found independently of the estrous condition. Insemination did not changed the levels of uterine pH, % of CO2 and HCO3− concentration, -E(-)AI = E(+)AI-, but all the values were affected by the estrous cycle in a way that decreased significantly at diestrous condition - E(-)AI and E(+)AI > NE-. Conclusions A non-invasive approach to the porcine uterus with novel optical probes allowed the obtaining of in situ physiological values of pH, CO2, and HCO3− at different reproductive conditions. While the short-time presence of sperm in the uterus did not change the physiological milieu, the whole pH-CO2-HCO3− system was affected by the estrous cycle. This study contributes to a better understanding of the in vivo regulation of the pH/CO2/HCO3− system in the uterus and may help to optimize the protocols of sperm treatment for in vitro fertilization.


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