Altered membrane dynamics of quantum dot-conjugated integrins during osteogenic differentiation of human bone marrow derived progenitor cells.
AuthorsChen H,Titushkin I,Stroscio M,Cho M
JournalBiophysical journal
PubMed ID17114225
Functionalized quantum dots offer several advantages for tracking the motion of individual molecules on the cell surface, including selective binding, precise optical identification of cell surface molecules, and detailed examination of the molecular motion without photobleaching. We have used quantum dots conjugated with integrin antibodies and performed studies to quantitatively ... More
Quantitating intracellular transport of polyplexes by spatio-temporal image correlation spectroscopy.
AuthorsKulkarni RP, Wu DD, Davis ME, Fraser SE
JournalProc Natl Acad Sci U S A
PubMed ID15897455
'Quantitatively understanding how nonviral gene delivery vectors (polyplexes) are transported inside cells is essential before they can be optimized for gene therapy and medical applications. In this study, we used spatio-temporal image correlation spectroscopy (ICS) to follow polymer-nucleic acid particles (polyplexes) of various sizes and analyze their diffusive-like and flow ... More
The photon counting histogram in fluorescence fluctuation spectroscopy.
AuthorsChen Y, Müller JD, So PT, Gratton E
JournalBiophys J
PubMed ID10388780
'Fluorescence correlation spectroscopy (FCS) is generally used to obtain information about the number of fluorescent particles in a small volume and the diffusion coefficient from the autocorrelation function of the fluorescence signal. Here we demonstrate that photon counting histogram (PCH) analysis constitutes a novel tool for extracting quantities from fluorescence ... More
Thermal fluctuations of grafted microtubules provide evidence of a length-dependent persistence length.
AuthorsPampaloni F, Lattanzi G, Jonás A, Surrey T, Frey E, Florin EL
JournalProc Natl Acad Sci U S A
PubMed ID16801537
'Microtubules are hollow cylindrical structures that constitute one of the three major classes of cytoskeletal filaments. On the mesoscopic length scale of a cell, their material properties are characterized by a single stiffness parameter, the persistence length l(p). Its value, in general, depends on the microscopic interactions between the constituent ... More
Why molecules move along a temperature gradient.
AuthorsDuhr S, Braun D
JournalProc Natl Acad Sci U S A
PubMed ID17164337
'Molecules drift along temperature gradients, an effect called thermophoresis, the Soret effect, or thermodiffusion. In liquids, its theoretical foundation is the subject of a long-standing debate. By using an all-optical microfluidic fluorescence method, we present experimental results for DNA and polystyrene beads over a large range of particle sizes, salt ... More
Rapid transport of large polymeric nanoparticles in fresh undiluted human mucus.
AuthorsLai SK, O'Hanlon DE, Harrold S, Man ST, Wang YY, Cone R, Hanes J
JournalProc Natl Acad Sci U S A
PubMed ID17244708
'Nanoparticles larger than the reported mesh-pore size range (10-200 nm) in mucus have been thought to be much too large to undergo rapid diffusional transport through mucus barriers. However, large nanoparticles are preferred for higher drug encapsulation efficiency and the ability to provide sustained delivery of a wider array of ... More
Enhanced viscoelasticity of human cystic fibrotic sputum correlates with increasing microheterogeneity in particle transport.
AuthorsDawson M, Wirtz D, Hanes J,
JournalJ Biol Chem
PubMed ID13679362
Current biochemical characterizations of cystic fibrosis (CF) sputum do not address the high degree of microheterogeneity in the rheological properties of the mucosal matrix and only provide bulk-average particle diffusion coefficients. The viscoelasticity of CF sputum greatly reduces the diffusion rates of colloidal particles, limiting the effectiveness of gene delivery ... More
Fluorescent microangiography (FMA): an improved tool to visualize the pulmonary microvasculature.
AuthorsDutly AE, Kugathasan L, Trogadis JE, Keshavjee SH, Stewart DJ, Courtman DW
JournalLab Invest
PubMed ID16518405
Visualization of the complex lung microvasculature and resolution of its three-dimensional architecture remains a difficult experimental challenge. We present a novel fluorescent microscopy technique to visualize both the normal and diseased pulmonary microvasculature. Physiologically relevant pulmonary perfusion conditions were applied using a low-viscosity perfusate infused under continuous airway ventilation. Intensely ... More
Mature dendritic cell generation promoted by lysophosphatidylcholine.
AuthorsCoutant F, Perrin-Cocon L, Agaugué S, Delair T, André P, Lotteau V
JournalJ Immunol
PubMed ID12165488
During the acute phase response, the interplay between high density lipoproteins and low density lipoproteins (LDL) favors transient generation of oxidized LDL with proinflammatory activities. We hypothesized that oxidative modification of LDL is an endogenous signal for the immune system, and we have shown that oxidized LDL promotes mature dendritic ... More
A parthenogenetic quasi-program causes teratoma-like tumors during aging in wild-type
AuthorsWang H, Zhao Y, Ezcurra M, Benedetto A, Gilliat AF, Hellberg J, Ren Z, Galimov ER, Athigapanich T, Girstmair J, Telford MJ, Dolphin CT, Zhang Z, Gems D
JournalNPJ Aging Mech Dis
PubMed ID29928508
'A long-standing belief is that aging (senescence) is the result of stochastic damage accumulation. Alternatively, senescent pathology may also result from late-life, wild-type gene action (i.e., antagonistic pleiotropy, as argued by Williams) leading to non-adaptive run-on of developmental programs (or' ... More
Numerical and Experimental Analyses of Three- Dimensional Unsteady Flow around a Micro-Pillar Subjected to Rotational Vibration.
AuthorsKaneko K, Osawa T, Kametani Y, Hayakawa T, Hasegawa Y, Suzuki H
JournalMicromachines (Basel)
PubMed ID30563012
The steady streaming (SS) phenomenon is gaining increased attention in the microfluidics community, because it can generate net mass flow from zero-mean vibration. We developed numerical simulation and experimental measurement tools to analyze this vibration-induced flow, which has been challenging due to its unsteady nature. The validity of these analysis ... More
A porcine ex vivo model of pigmentary glaucoma.
AuthorsDang Y, Waxman S, Wang C, Loewen RT, Sun M, Loewen NA
JournalSci Rep
PubMed ID29615741
Pigment dispersion can lead to pigmentary glaucoma, a poorly understood condition of younger myopic eyes with fluctuating high intraocular pressure. It has been difficult to investigate its pathogenesis without a model similar to human eyes in size and behavior. Here we present a porcine ex vivo model that recreates several ... More