Publications by authors named "Ryan Rich"

38 Publications

Retinal Vasculitis and Intraocular Inflammation after Intravitreal Injection of Brolucizumab.

Ophthalmology 2020 10 25;127(10):1345-1359. Epub 2020 Apr 25.

Bascom Palmer Eye Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida.

Purpose: To evaluate features and outcomes of eyes with retinal vasculitis and intraocular inflammation (IOI) after intravitreal injection (IVI) of brolucizumab 6 mg/0.05 ml for treatment of neovascular age-related macular degeneration.

Design: Retrospective case series.

Participants: Fifteen eyes from 12 patients identified from 10 United States centers.

Methods: Review of patient demographics, ophthalmologic examination results, and retinal imaging findings.

Main Outcome Measures: Baseline and follow-up visual acuity (VA), prior anti-vascular endothelial growth factor (VEGF) injections, clinical presentation, retinal findings, fluorescein angiography results, and treatment strategies.

Results: The number of previous anti-VEGF IVIs ranged between 2 and 80 in the affected eye before switching to brolucizumab. Retinal vasculitis and IOI were diagnosed at a mean of 30 days after brolucizumab IVI. Mean VA before brolucizumab IVI was 0.426 logarithm of the minimum angle of resolution (logMAR; Snellen equivalent, 20/53) and VA at diagnosis of retinal vasculitis was 0.981 logMAR (Snellen equivalent, 20/191; range, 20/25-20/1600; P = 0.008). All affected eyes showed IOI with variable combinations of focal or elongated segmental sheathing and discontinuity of small and large retinal arteries, sclerotic arteries, regions of vascular nonperfusion, cotton-wool spots, Kyrieleis plaques, irregular venous caliber with dilated and sclerotic segments, perivenular hemorrhages, and foci of phlebitis. Fluorescein angiography revealed delayed retinal arterial filling, retinal vascular nonperfusion, and variable dye leakage from affected vessels and the optic nerve. Systemic evaluation for embolic causes was unrevealing in 2 patients, and 3 patients showed negative laboratory assessment for uveitis. Treatment consisted of various combinations of corticosteroids (systemic, intravitreal, and topical), and 2 eyes underwent vitrectomy without improvement in vision. After a mean follow-up of 25 days, mean VA was 0.833 logMAR (Snellen equivalent, 20/136), which was reduced compared with baseline (P = 0.033).

Conclusions: Retinal vasculitis and IOI after brolucizumab IVI are characterized by variable occlusion of large or small retinal arteries, or both, and perivenular abnormalities. It may span from peripheral vasculitis to occlusion of large retinal arteries around the optic nerve or macula with severe vision loss. A high index of suspicion is required because vitreous cells may obscure visualization of retinal details.
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http://dx.doi.org/10.1016/j.ophtha.2020.04.017DOI Listing
October 2020

Biomechanical Assessment of Locking Plate Fixation of Comminuted Proximal Olecranon Fractures.

J Orthop Trauma 2018 11;32(11):e445-e450

Department of Orthopaedic Surgery, Warren Alpert School of Medicine, Brown University, Providence, RI.

Objectives: To determine if mean ultimate strength or failure mechanism differed between comminuted olecranon fractures created at the proximal 25% or 50% of the trochlear notch and fixed with precontoured posterior locking plates (PLPs).

Methods: Comminuted osteotomies were created in 10 matched pairs of cadaveric upper extremities at either the proximal 25% or 50% of the trochlear notch after quantitative computed tomography scans were performed to evaluate bone mineral density. Variable-angle olecranon PLPs were fixed to the specimens. The triceps tendon of each specimen was loaded cyclically and then to failure. Comparison of mean force at failure (displacement >2 mm) was performed using the 2-tailed t test.

Results: There were no significant differences in specimen bone mineral density within matched pairs. Nineteen specimens failed by olecranon bisection fracture in the sagittal plane. Specimens in the 25% osteotomy group failed at lower ultimate forces of 808 N (SD ± 474 N) versus 1058 N (SD ± 480 N) in the 50% osteotomy group (P = 0.044).

Conclusions: The ultimate strength of comminuted olecranon fracture fixation with a PLP decreases significantly if the fracture is proximal to the midpoint of the trochlear notch. Fractures proximal to the midpoint of the trochlear notch may benefit from supplemental fixation or suture augmentation to prevent failure, particularly at force ranges higher than those experienced during active elbow range of motion.
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http://dx.doi.org/10.1097/BOT.0000000000001279DOI Listing
November 2018

No Difference in Myosin Kinetics and Spatial Distribution of the Lever Arm in the Left and Right Ventricles of Human Hearts.

Front Physiol 2017 13;8:732. Epub 2017 Oct 13.

Department of Cell Biology and Center for Commercialization of Fluorescence Technologies, University of North Texas, Health Science Center, Fort Worth, TX, United States.

The systemic circulation offers larger resistance to the blood flow than the pulmonary system. Consequently, the left ventricle (LV) must pump blood with more force than the right ventricle (RV). The question arises whether the stronger pumping action of the LV is due to a more efficient action of left ventricular myosin, or whether it is due to the morphological differences between ventricles. Such a question cannot be answered by studying the entire ventricles or myocytes because any observed differences would be wiped out by averaging the information obtained from trillions of myosin molecules present in a ventricle or myocyte. We therefore searched for the differences between single myosin molecules of the LV and RV of failing hearts . We show that the parameters that define the mechanical characteristics of working myosin (kinetic rates and the distribution of spatial orientation of myosin lever arm) were the same in both ventricles. These results suggest that there is no difference in the way myosin interacts with thin filaments in myocytes of failing hearts, and suggests that the difference in pumping efficiencies are caused by interactions between muscle proteins other than myosin or that they are purely morphological.
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http://dx.doi.org/10.3389/fphys.2017.00732DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5645524PMC
October 2017

A Novel Method of Determining the Functional Effects of a Minor Genetic Modification of a Protein.

Front Cardiovasc Med 2015 18;2:35. Epub 2015 Nov 18.

Department of Cell Biology, Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center , Fort Worth, TX , USA.

Contraction of muscles results from the ATP-coupled cyclic interactions of the myosin cross-bridges with actin filaments. Macroscopic parameters of contraction, such as maximum tension, speed of shortening, or ATPase activity, are unlikely to reveal differences between the wild-type and mutated (MUT) proteins when the level of transgenic protein expression is low. This is because macroscopic measurements are made on whole organs containing trillions of actin and myosin molecules. An average of the information collected from such a large assembly is bound to conceal any differences imposed by a small fraction of MUT molecules. To circumvent the averaging problem, the measurements were done on isolated ventricular myofibril (MF) in which thin filaments were sparsely labeled with a fluorescent dye. We isolated a single MF from a ventricle, oriented it vertically (to be able measure the orientation), and labeled 1 in 100,000 actin monomers with a fluorescent dye. We observed the fluorescence from a small confocal volume containing approximately three actin molecules. During the contraction of a ventricle actin constantly changes orientation (i.e., the transition moment of rigidly attached fluorophore fluctuates in time) because it is repetitively being "kicked" by myosin cross-bridges. An autocorrelation functions (ACFs) of these fluctuations are remarkably sensitive to the mutation of myosin. We examined the effects of Alanine to Threonine (A13T) mutation in the myosin regulatory light chain shown by population studies to cause hypertrophic cardiomyopathy. This is an appropriate example, because mutation is expressed at only 10% in the ventricles of transgenic mice. ACFs were either "Standard" (Std) (decaying monotonically in time) or "Non-standard" (NStd) (decaying irregularly). The sparse labeling of actin also allowed the measurement of the spatial distribution of actin molecules. Such distribution reflects the interaction of actin with myosin cross-bridges and is also remarkably sensitive to myosin mutation. The result showed that the A13T mutation caused 9% ACFs and 9% of spatial distributions of actin to be NStd, while the remaining 91% were Std, suggesting that the NStd performances were executed by the MUT myosin heads and that the Std performances were executed by non-MUT myosin heads. We conclude that the method explored in this study is a sensitive and valid test of the properties of low prevalence mutations in sarcomeric proteins.
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http://dx.doi.org/10.3389/fcvm.2015.00035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4671333PMC
December 2015

Steady State and Time Resolved Fluorescence Studies of Azadioxatriangulenium (ADOTA) Fluorophore in Silica and PVA Thin Films.

Dyes Pigm 2015 Jun;117:16-23

Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107,USA.

A cationic azadioxatriangulenium (ADOTA) dye was entrapped in silica thin films obtained by the sol-gel process and in poly (vinyl) alcohol (PVA) thin films. Azadioxatriangulenium is a red emitting fluorophore with a long fluorescence lifetime of ~20 ns. The fluorescent properties of azadioxatriangulenium in silica thin films and PVA films were studied by means of steady-state and time resolved fluorescence techniques. We have found that the azadioxatriangulenium entrapped in silica thin film has a wider fluorescence lifetime distribution (Lorentzian distribution), lower fluorescence efficiencies, shorter lifetimes compared to Azadioxatriangulenium in a PVA film. The local environment of azadioxatriangulenium molecules in the silica thin film is rich with water and ethanol, which creates the possibility of forming excited state aggregates due to high concentration of dye within a small confined area. In contrast to the PVA matrices, the porous silica films allow restricted rotations of Azadioxatriangulenium molecules, which result in faster and complex fluorescence anisotropy decays suggesting energy migration among dye molecules.
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http://dx.doi.org/10.1016/j.dyepig.2015.01.027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4648278PMC
June 2015

Sandwich type plasmonic platform for MEF using silver fractals.

Nanoscale 2015 Nov;7(42):17729-34

Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, TX, USA.

In this report, we describe a plasmonic platform with silver fractals for metal enhanced fluorescence (MEF) measurements. When a dye containing surface was brought into contact with silver fractals, a significantly enhanced fluorescence signal from the dye was observed. Fluorescence enhancement was studied with the N-methyl-azadioxatriangulenium chloride salt (Me-ADOTA·Cl) in PVA films made from 0.2% PVA (w/v) solution spin-coated on a clean glass coverslip. The Plasmonic Platforms (PP) were assembled by pressing together silver fractals on one glass slide and a separate glass coverslip spin-coated with a uniform Me-ADOTA·Cl in PVA film. In addition, we also tested ADOTA labeled human serum albumin (HSA) deposited on a glass slide for potential PP bioassay applications. Using the new PP, we could achieve more than a 20-fold fluorescence enhancement (bright spots) accompanied by a decrease in the fluorescence lifetime. The experimental results were used to calculate the extinction (excitation) enhancement factor (GA) and fluorescence radiative rate enhancements factor (GF). No change in emission spectrum was observed for a dye with or without contact with fractals. Our studies indicate that this type of PP can be a convenient approach for constructing assays utilizing metal enhanced fluorescence (MEF) without the need for depositing the material directly on metal structures platforms.
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http://dx.doi.org/10.1039/c5nr05834aDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4808630PMC
November 2015

Methylene blue protects astrocytes against glucose oxygen deprivation by improving cellular respiration.

PLoS One 2015 7;10(4):e0123096. Epub 2015 Apr 7.

Department of Pharmacology and Neuroscience, Institute for Aging and Alzheimer's Disease Research, University of North Texas Health Science Center, Fort Worth, Texas, United States of America.

Astrocytes outnumber neurons and serve many metabolic and trophic functions in the mammalian brain. Preserving astrocytes is critical for normal brain function as well as for protecting the brain against various insults. Our previous studies have indicated that methylene blue (MB) functions as an alternative electron carrier and enhances brain metabolism. In addition, MB has been shown to be protective against neurodegeneration and brain injury. In the current study, we investigated the protective role of MB in astrocytes. Cell viability assays showed that MB treatment significantly protected primary astrocytes from oxygen-glucose deprivation (OGD) & reoxygenation induced cell death. We also studied the effect of MB on cellular oxygen and glucose metabolism in primary astrocytes following OGD-reoxygenation injury. MB treatment significantly increased cellular oxygen consumption, glucose uptake and ATP production in primary astrocytes. In conclusion our study demonstrated that MB protects astrocytes against OGD-reoxygenation injury by improving astrocyte cellular respiration.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0123096PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4388695PMC
January 2016

Surrogate headform accelerations associated with stick checks in girls' lacrosse.

J Appl Biomech 2015 Apr 20;31(2):122-7. Epub 2014 Nov 20.

Bioengineering Laboratory, Department of Orthopaedics, Warren Alpert Medical School of Brown University, and Rhode Island Hospital, Providence, RI.

Girls' lacrosse is fundamentally a different sport than boys' lacrosse, and girls are not required to wear protective headgear. Recent epidemiological studies have found that stick checks are the leading cause of concussion injury in girls' lacrosse. The purpose of this study was to determine stick check speeds and estimate the head acceleration associated with direct checks to the head. In addition, we briefly examine if commercially available headgear can mitigate the accelerations. Seven (n = 7) experienced female lacrosse players checked, with varying severity, a NOSCAE and an ASTM headform. Stick speed at impact and the associated peak linear accelerations of the headform were recorded. The NOCSAE headform was fitted with four commercially available headgear and similar stick impact testing was performed. The median stick impact speed was 8.1 m/s and 777 deg/s. At these speeds, peak linear acceleration was approximately 60g. Three out of the four headgear significantly reduced the peak linear acceleration when compared with the bare headform. These data serve as baseline for understanding the potential mechanism and reduction of concussions from stick impacts in girls' lacrosse.
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http://dx.doi.org/10.1123/jab.2014-0102DOI Listing
April 2015

Preparation of plasmonic platforms of silver wires on gold mirrors and their application to surface enhanced fluorescence.

ACS Appl Mater Interfaces 2014 22;6(21):18780-7. Epub 2014 Oct 22.

Department of Chemistry, The University of Texas at Tyler , 3900 University Boulevard, Tyler, Texas 75799, United States.

In this report we describe a preparation of silver wires (SWs) on gold mirrors and its application to surface enhanced fluorescence (SEF) using a new methodology. Silica protected gold mirrors were drop-coated with a solution of silver triangular nanoprisms. The triangular nanoprisms were slowly air-dried to get silver wires that self-assembled on the gold mirrors. Fluorescence enhancement was studied using methyl azadioxatriangulenium chloride (Me-ADOTA · Cl) dye in PVA spin-coated on a clean glass coverslip. New Plasmonic Platforms (PPs) were assembled by placing a mirror with SWs in contact with a glass coverslip spin-coated with a uniform Me-ADOTA · Cl film. It was shown that surface enhanced fluorescence is a real phenomenon, not just an enhancement of the fluorescence signal due to an accumulation of the fluorophore on rough nanostructure surfaces. The average fluorescence enhancement was found to be about 15-fold. The lifetime of Me-ADOTA · Cl dye was significantly reduced (∼ 4 times) in the presence of SWs. Moreover, fluorescence enhancement and lifetime did not show any dependence on the excitation light polarization.
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http://dx.doi.org/10.1021/am504431jDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4232249PMC
October 2015

BSA Au clusters as a probe for enhanced fluorescence detection using multipulse excitation scheme.

Curr Pharm Biotechnol 2014 ;14(13):1139-44

Center for Fluorescence Technologies and Nanomedicine, UNT Health Science Center, Fort Worth, TX, 76107l, USA.

Although BSA Au clusters fluoresce in red region (λmax: 650 nm), they are of limited use due to low fluorescence quantum yield (~6%). Here we report an enhanced fluorescence imaging application of fluorescent bio-nano probe BSA Au clusters using multipulse excitation scheme. Multipulse excitation takes advantage of long fluorescence lifetime (> 1 µs) of BSA Au clusters and enhances its fluorescence intensity 15 times over short lived cellular auto-fluorescence. Moreover we have also shown that by using time gated detection strategy signal (fluorescence of BSA Au clusters) to noise (auto-fluorescence) ratio can be increased by 30 fold. Thereby with multipulse excitation long lifetime probes can be used to develop biochemical assays and perform optical imaging with zero background.
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http://dx.doi.org/10.2174/1389201015666140523161038DOI Listing
June 2015

Membrane topology of human presenilin-1 in SK-N-SH cells determined by fluorescence correlation spectroscopy and fluorescent energy transfer.

Cell Biochem Biophys 2014 Nov;70(2):923-32

Department of Cell Biology & Immunology and Center for Commercialization of Fluorescence Technologies, UNT Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA.

Presenilin-1 (PS1) protein acts as passive ER Ca(2+) leak channels that facilitate passive Ca(2+) leak across ER membrane. Mutations in the gene encoding PS1 protein cause neurodegeneration in the brains of patients with familial Alzheimer's disease (FAD). FADPS1 mutations abrogate the function of ER Ca(2+) leak channel activity in human neuroblastoma SK-N-SH cells in vitro (Das et al., J Neurochem 122(3):487-500, 2012) and in mouse embryonic fibroblasts. Consequently, genetic deletion or mutations of the PS1 gene cause calcium (Ca(2+)) signaling abnormalities leading to neurodegeneration in FAD patients. By analogy with other known ion channels it has been proposed that the functional PS1 channels in ER may be multimers of several PS1 subunits. To test this hypothesis, we conjugated the human PS1 protein with an NH2-terminal YFP-tag and a COOH-terminal CFP-tag. As expected YFP-PS1, and PS1-CFP were found to be expressed on the plasma membranes by TIRF microscopy, and both these fusion proteins increased ER Ca(2+) leak channel activity similar to PS1 (WT) in SK-N-SH cells, as determined by functional calcium imaging. PS1-CFP was either expressed alone or together with YFP-PS1 into SK-N-SH cell line and the interaction between YFP-PS1 and PS1-CFP was determined by Förster resonance energy transfer analysis. Our results suggest interaction between YFP-PS1 and PS1-CFP confirming the presence of a dimeric or multimeric form of PS1 in SK-N-SH cells. Lateral diffusion of PS1-CFP and YFP-PS1 in the plasma membrane of SK-N-SH cells was measured in the absence or in the presence of glycerol by fluorescence correlation spectroscopy to show that both COOH-terminal and NH2-terminal of human PS1 are located on the cytoplasmic side of the plasma membrane. Therefore, we conclude that both COOH-terminal and NH2-terminal of human PS1 may also be oriented on the cytosolic side of ER membrane.
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http://dx.doi.org/10.1007/s12013-014-9999-zDOI Listing
November 2014

Generating multiple-pulse bursts for enhanced fluorescence detection.

Methods Appl Fluoresc 2014 May 14;2(2):024009. Epub 2014 May 14.

Department of Physics & Astronomy, Texas Christian University, Fort Worth, TX 76129, USA.

The signal-to-background ratio is the limiting factor for fluorescence based detection, sensing, and imaging. A typical background signal will include direct scattering of excitation and Raman scattering of the sample as well as autofluorescence from the sample and additives. To improve the signal-to-background ratio, fluorophores of high brightness and/or high concentration of the fluorophores need to be used. Most of the background is instantaneous and short-lived (picosecond to nanosecond time scale), and using long-lived fluorescence probes combined with time-gated detection allows for significant suppression of unwanted background. Unfortunately, this approach requires substantial sacrifice of the probe signal in order to sufficiently filter the background unless the fluorescence lifetime of the probe is very long. However, long lived probes like ruthenium bipyridyl have relatively low brightness compared to probes that have shorter, 10-30 ns fluorescence lifetimes.We recently presented an approach based on bursts of multiple pulses that allowed for high probe signal amplification using long-lived ruthenium based probe (Ru) and an 80 MHz repetition-rate laser excitation. Unfortunately, Ru represents an extreme case for probe lifetime, and a probe with a shorter lifetime of 20 ns will require excitation from a pulsed source with much higher repetition rate to significantly enhance its signal. Such high repetition rates are not possible to generate with most of today's available electronics. In this report we present new approaches to optimize and generate bursts of pulses with high repetition rate within the burst and no need for new or improved electronics. The high repetition rates originate from a low-repetition source and are highly tunable. We demonstrate that a burst of 2-10 pulses spaced 3 ns apart (corresponding to a 'burst repetition rate' of 330 MHz) allows for high signal enhancement of the 20 ns probe over the sub-nanosecond/nanosecond background. Such an approach can be applied for any sensing format, allowing much higher sensitivity for detection. Since the energy of a single pulse is spread over a few pulses in the burst, the fluorophore's photostability also improves.
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http://dx.doi.org/10.1088/2050-6120/2/2/024009DOI Listing
May 2014

Phosphorylation of myosin regulatory light chain has minimal effect on kinetics and distribution of orientations of cross bridges of rabbit skeletal muscle.

Am J Physiol Regul Integr Comp Physiol 2014 Feb 27;306(4):R222-33. Epub 2013 Nov 27.

Department of Molecular Biology and Immunology and Center for Commercialization of Fluorescence Technologies, University of North Texas, Health Science Center, Fort Worth, Texas.

Force production in muscle results from ATP-driven cyclic interactions of myosin with actin. A myosin cross bridge consists of a globular head domain, containing actin and ATP-binding sites, and a neck domain with the associated light chain 1 (LC1) and the regulatory light chain (RLC). The actin polymer serves as a "rail" over which myosin translates. Phosphorylation of the RLC is thought to play a significant role in the regulation of muscle relaxation by increasing the degree of skeletal cross-bridge disorder and increasing muscle ATPase activity. The effect of phosphorylation on skeletal cross-bridge kinetics and the distribution of orientations during steady-state contraction of rabbit muscle is investigated here. Because the kinetics and orientation of an assembly of cross bridges (XBs) can only be studied when an individual XB makes a significant contribution to the overall signal, the number of observed XBs was minimized to ∼20 by limiting the detection volume and concentration of fluorescent XBs. The autofluorescence and photobleaching from an ex vivo sample was reduced by choosing a dye that was excited in the red and observed in the far red. The interference from scattering was eliminated by gating the signal. These techniques decrease large uncertainties associated with determination of the effect of phosphorylation on a few molecules ex vivo with millisecond time resolution. In spite of the remaining uncertainties, we conclude that the state of phosphorylation of RLC had no effect on the rate of dissociation of cross bridges from thin filaments, on the rate of myosin head binding to thin filaments, and on the rate of power stroke. On the other hand, phosphorylation slightly increased the degree of disorder of active cross bridges.
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http://dx.doi.org/10.1152/ajpregu.00382.2013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3921311PMC
February 2014

Resonance energy transfer between fluorescent BSA protected Au nanoclusters and organic fluorophores.

Nanoscale 2014 Jan 8;6(1):385-91. Epub 2013 Nov 8.

Center for Commercialization of Fluorescence Technologies, Department of Molecular Biology and Immunology, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, Texas 76107, USA.

Bovine serum albumin (BSA) protected nanoclusters (Au and Ag) represent a group of nanomaterials that holds great promise in biophysical applications due to their unique fluorescence properties and lack of toxicity. These metal nanoclusters have utility in a variety of disciplines including catalysis, biosensing, photonics, imaging and molecular electronics. However, they suffer from several disadvantages such as low fluorescence quantum efficiency (typically near 6%) and broad emission spectrum (540 nm to 800 nm). We describe an approach to enhance the apparent brightness of BSA Au clusters by linking them with a high extinction donor organic dye pacific blue (PB). In this conjugate PB acts as a donor to BSA Au clusters and enhances its brightness by resonance energy transfer (RET). We found that the emission of BSA Au clusters can be enhanced by a magnitude of two-fold by resonance energy transfer (RET) from the high extinction donor PB, and BSA Au clusters can act as an acceptor to nanosecond lifetime organic dyes. By pumping the BSA Au clusters using a high extinction donor, one can increase the effective brightness of less bright fluorophores like BSA Au clusters. Moreover, we prepared another conjugate of BSA Au clusters with the near infrared (NIR) dye Dylight 750 (Dy750), where BSA Au clusters act as a donor to Dy750. We observed that BSA Au clusters can function as a donor, showing 46% transfer efficiency to the NIR dye Dy750 with a long lifetime component in the acceptor decay through RET. Such RET-based probes can be used to prevent the problems of a broad emission spectrum associated with the BSA Au clusters. Moreover, transferring energy from BSA Au clusters to Dy750 will result in a RET probe with a narrow emission spectrum and long lifetime component which can be utilized in imaging applications.
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http://dx.doi.org/10.1039/c3nr03886fDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3918500PMC
January 2014

Multiple-pulse pumping for enhanced fluorescence detection and molecular imaging in tissue.

Methods 2014 Mar 29;66(2):292-8. Epub 2013 Aug 29.

Department of Molecular Biology and Immunology, Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, Fort Worth, TX 76107, USA; Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129, USA. Electronic address:

Applications of fluorescence based imaging techniques for detection in cellular and tissue environments are severely limited by autofluorescence of endogenous components of cells, tissue, and the fixatives used in sample processing. To achieve sufficient signal-to-background ratio, a high concentration of the probe needs to be used which is not always feasible. Since typically autofluorescence is in the nanosecond range, long-lived fluorescence probes in combination with time-gated detection can be used for suppression of unwanted autofluorescence. Unfortunately, this requires the sacrifice of the large portion the probe signal in order to sufficiently filter the background. We report a simple and practical approach to achieve a many-fold increase in the intensity of a long-lived probe without increasing the background fluorescence. Using controllable, well separated bursts of closely spaced laser excitation pulses, we are able to highly increase the fluorescence signal of a long-lived marker over the endogenous fluorescent background and scattering, thereby greatly increasing detection sensitivity. Using a commercially available confocal microscopy system equipped with a laser diode and time correlated single photon counting (TCSPC) detection, we are able to enhance the signal of a long-lived Ruthenium (Ru)-based probe by nearly an order of magnitude. We used 80 MHz bursts of pulses (12.5 ns pulse separation) repeated with a 320 kHz repetition rate as needed to adequately image a dye with a 380 ns lifetime. Just using 10 pulses in the burst increases the Ru signal almost 10-fold without any increase in the background signal.
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http://dx.doi.org/10.1016/j.ymeth.2013.08.026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3938978PMC
March 2014

Fluorescent Polyelectrolyte Capped Silver Nanoclusters: Optimization and Spectroscopic Evaluation.

Chem Phys Lett 2012 Oct;549:72-76

Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, 3500 Camp Bowie Blvd. Fort Worth, Texas, USA, 76107.

In the present work, we have synthesized water soluble Ag nanoclusters using PMAA as a template with different Ag+: COO-ratios, to optimize it for highest brightness using less UV exposure time. Fluorescence polarization was 0.30 for and was found to vary with excitation and emission wavelength with few hundred picoseconds average fluorescence lifetime. Fluorescence Correlation Spectroscopy data depicts slower diffusion at red excitation compared to blue excitation in confocal volume than conventionally synthesized colloids proving presence of multiple sizes. The optical properties of the particles are dependent upon the excitation wavelength used and the emission wavelength collected.
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http://dx.doi.org/10.1016/j.cplett.2012.08.042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3678839PMC
October 2012

Fabrication and size dependent properties of porous silicon nanotube arrays.

Chem Commun (Camb) 2013 Jun;49(51):5760-2

Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA.

A general method for the formation of a broad family of silicon nanotube arrays (Si NTAs) relevant to diverse fields--ranging from energy storage to therapeutic platforms--is described. Such nanotubes demonstrate a thickness-dependent dissolution behavior important to its potential use in drug delivery. Under selected conditions, novel porous silicon nanotubes can be prepared when the shell thickness is on the order of 12 nm or less, capable of being loaded with small molecules such as luminescent ruthenium dyes associated with dye-sensitized photovoltaic devices.
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http://dx.doi.org/10.1039/c3cc41913dDOI Listing
June 2013

Elimination of autofluorescence in fluorescence correlation spectroscopy using the AzaDiOxaTriAngulenium (ADOTA) fluorophore in combination with time-correlated single-photon counting (TCSPC).

Anal Bioanal Chem 2013 May 6;405(14):4887-94. Epub 2013 Apr 6.

Department of Molecular Biology and Immunology, Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.

Fluorescence correlation spectroscopy (FCS) is a frequently applied technique that allows for the precise and sensitive analysis of molecular diffusion and interactions. However, the potential of FCS for in vitro or ex vivo studies has not been fully realized due in part to artifacts originating from autofluorescence (fluorescence of inherent components and fixative-induced fluorescence). Here, we propose the azadioxatriangulenium (ADOTA) dye as a solution to this problem. The lifetime of the ADOTA probe, about 19.4 ns, is much longer than most components of autofluorescence. Thus, it can be easily separated by time-correlated single-photon counting methods. Here, we demonstrate the suppression of autofluorescence in FCS using ADOTA-labeled hyaluronan macromolecules (HAs) with Rhodamine 123 added to simulate diffusing fluorescent background components. The emission spectrum and decay rate of Rhodamine 123 overlap with the usual sources of autofluorescence, and its diffusion behavior is well known. We show that the contributions from Rhodamine 123 can be eliminated by time gating or by fluorescence lifetime correlation spectroscopy (FLCS). While the pairing of ADOTA and time gating is an effective strategy for the removal of autofluorescence from fluorescence imaging, the loss of photons leads to erroneous concentration values with FCS. On the other hand, FLCS eliminates autofluorescence without such errors. We then show that both time gating and FLCS may be used successfully with ADOTA-labeled HA to detect the presence of hyaluronidase, the overexpression of which has been observed in many types of cancer.
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http://dx.doi.org/10.1007/s00216-013-6879-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3660553PMC
May 2013

Two Photon Induced Luminescence of BSA Protected Gold Clusters.

Chem Phys Lett 2013 Mar;561-562:74-76

Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, 3500 Camp Bowie Blvd. Fort Worth, Texas, USA, 76107 ; Department of Cell Biology and Anatomy, University of North Texas Health Science Center. 3500 Camp Bowie Blvd. Fort Worth, Texas, USA, 76107.

In this short letter, we have synthesized the BSA protected Au nanoclusters and studied their two photon luminescence behavior. We demonstrate that BSA Au nanoclusters can be used as a probe with two photon excitation capability. Our results show a quadratic relation between excitation power and emission intensity whereas with one photon excitation shows a linear dependence. The emission spectrum of BSA Au nanoclusters with one photon and two photon excitation shows no appreciable change. Due to its long wavelength emission (650 nm) and two photon excitation, BSA Au can be potentially used as a probe for deep tissue imaging.
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http://dx.doi.org/10.1016/j.cplett.2013.01.028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4665100PMC
March 2013

Polarization properties of fluorescent BSA protected Au25 nanoclusters.

Nanoscale 2013 Apr 8;5(8):3441-6. Epub 2013 Mar 8.

Center for Commercialization of Fluorescence Technologies, Department of Molecular Biology and immunology, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, Texas 76107, USA.

BSA protected gold nanoclusters (Au25) are attracting a great deal of attention due to their unique spectroscopic properties and possible use in biophysical applications. Although there are reports on synthetic strategies, spectroscopy and applications, little is known about their polarization behavior. In this study, we synthesized the BSA protected Au25 nanoclusters and studied their steady state and time resolved fluorescence properties including polarization behavior in different solvents: glycerol, propylene glycol and water. We demonstrated that the nanocluster absorption spectrum can be separated from the extinction spectrum by subtraction of Rayleigh scattering. The nanocluster absorption spectrum is well approximated by three Gaussian components. By a comparison of the emissions from BSA Au25 clusters and rhodamine B in water, we estimated the quantum yield of nanoclusters to be higher than 0.06. The fluorescence lifetime of BSA Au25 clusters is long and heterogeneous with an average value of 1.84 μs. In glycerol at -20 °C the anisotropy is high, reaching a value of 0.35. However, the excitation anisotropy strongly depends on the excitation wavelengths indicating a significant overlap of the different transition moments. The anisotropy decay in water reveals a correlation time below 0.2 μs. In propylene glycol the measured correlation time is longer and the initial anisotropy depends on the excitation wavelength. BSA Au25 clusters, due to long lifetime and high polarization, can potentially be used in studying large macromolecules such as protein complexes with large molecular weight.
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http://dx.doi.org/10.1039/c3nr34152fDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3857347PMC
April 2013

Hybrid optical materials of plasmon-coupled CdSe/ZnS coreshells for photonic applications.

Opt Mater Express 2012 Aug 5;2(8):1026-1039. Epub 2012 Jul 5.

Advanced Center for Laser Science and Spectroscopy, Department of Physics, Hampton University, Hampton, Virginia 23668, USA.

A hybrid optical nanostructure of plasmon-coupled SQDs was developed for photonic applications. The coupling distances between the mono-layers of Au nanoparticles with a surface concentration of ~9.18 × 10 nm and CdSe/ZnS SQDs with that of ~3.7 × 10 nm were controlled by PMMA plasma etching. Time-resolved spectroscopy of plasmon-coupled SQDs revealed a strong shortening of the longest lifetime and ~9-fold PL enhancement. Polarization-resolved PL spectroscopy displayed linear polarization and depolarization at near- and far-field plasmon-coupling, respectively. The physical origin of PL enhancement could be attributable to both the large local field enhancement and the fast resonant energy transfer.
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http://dx.doi.org/10.1364/OME.2.001026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3583368PMC
August 2012

FRET based ratio-metric sensing of hyaluronidase in synthetic urine as a biomarker for bladder and prostate cancer.

Curr Pharm Biotechnol 2013 ;14(4):470-4

Department of Molecular Biology and Immunology, Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.

Elevated hyaluronidase levels are found in the urine of bladder and prostate cancer patients. Therefore, HA-ase is regarded as an important biomarker for the detection of these cancers. In this report, we use a FRET based ratiometric sensing approach to detect the level of HA-ase in synthetic urine. For this, we have used a HA-FRET probe (hyaluronan) labeled with fluorescein as a donor and rhodamine as an acceptor. We monitor the digestion of our HA-FRET probe with different concentrations of HA-ase in synthetic urine via fluorescence emission. The extent to which FRET is released depends on the concentration of HA-ase. Our fluorescence intensity results are also supported with time resolved fluorescence decay data. This assay can be used to develop a non-invasive technique for the detection of bladder and/or prostate cancer progression.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3919880PMC
http://dx.doi.org/10.2174/13892010113149990222DOI Listing
October 2014

Comparison of orientation and rotational motion of skeletal muscle cross-bridges containing phosphorylated and dephosphorylated myosin regulatory light chain.

J Biol Chem 2013 Mar 14;288(10):7012-23. Epub 2013 Jan 14.

Department of Cell Biology and Anatomy, University of North Texas, Health Science Center, Fort Worth, Texas 76107, USA.

Calcium binding to thin filaments is a major element controlling active force generation in striated muscles. Recent evidence suggests that processes other than Ca(2+) binding, such as phosphorylation of myosin regulatory light chain (RLC) also controls contraction of vertebrate striated muscle (Cooke, R. (2011) Biophys. Rev. 3, 33-45). Electron paramagnetic resonance (EPR) studies using nucleotide analog spin label probes showed that dephosphorylated myosin heads are highly ordered in the relaxed fibers and have very low ATPase activity. This ordered structure of myosin cross-bridges disappears with the phosphorylation of RLC (Stewart, M. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 430-435). The slower ATPase activity in the dephosporylated moiety has been defined as a new super-relaxed state (SRX). It can be observed in both skeletal and cardiac muscle fibers (Hooijman, P., Stewart, M. A., and Cooke, R. (2011) Biophys. J. 100, 1969-1976). Given the importance of the finding that suggests a novel pathway of regulation of skeletal muscle, we aim to examine the effects of phosphorylation on cross-bridge orientation and rotational motion. We find that: (i) relaxed cross-bridges, but not active ones, are statistically better ordered in muscle where the RLC is dephosporylated compared with phosphorylated RLC; (ii) relaxed phosphorylated and dephosphorylated cross-bridges rotate equally slowly; and (iii) active phosphorylated cross-bridges rotate considerably faster than dephosphorylated ones during isometric contraction but the duty cycle remained the same, suggesting that both phosphorylated and dephosphorylated muscles develop the same isometric tension at full Ca(2+) saturation. A simple theory was developed to account for this fact.
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http://dx.doi.org/10.1074/jbc.M112.434209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3591611PMC
March 2013

Elimination of autofluorescence background from fluorescence tissue images by use of time-gated detection and the AzaDiOxaTriAngulenium (ADOTA) fluorophore.

Anal Bioanal Chem 2013 Feb 20;405(6):2065-75. Epub 2012 Dec 20.

Department of Molecular Biology and Immunology, Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.

Sample autofluorescence (fluorescence of inherent components of tissue and fixative-induced fluorescence) is a significant problem in direct imaging of molecular processes in biological samples. A large variety of naturally occurring fluorescent components in tissue results in broad emission that overlaps the emission of typical fluorescent dyes used for tissue labeling. In addition, autofluorescence is characterized by complex fluorescence intensity decay composed of multiple components whose lifetimes range from sub-nanoseconds to a few nanoseconds. For these reasons, the real fluorescence signal of the probe is difficult to separate from the unwanted autofluorescence. Here we present a method for reducing the autofluorescence problem by utilizing an azadioxatriangulenium (ADOTA) dye with a fluorescence lifetime of approximately 15 ns, much longer than those of most of the components of autofluorescence. A probe with such a long lifetime enables us to use time-gated intensity imaging to separate the signal of the targeting dye from the autofluorescence. We have shown experimentally that by discarding photons detected within the first 20 ns of the excitation pulse, the signal-to-background ratio is improved fivefold. This time-gating eliminates over 96 % of autofluorescence. Analysis using a variable time-gate may enable quantitative determination of the bound probe without the contributions from the background.
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http://dx.doi.org/10.1007/s00216-012-6623-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3566262PMC
February 2013

Detection of hyaluronidase activity using fluorescein labeled hyaluronic acid and Fluorescence Correlation Spectroscopy.

J Photochem Photobiol B 2012 Nov 31;116:7-12. Epub 2012 Jul 31.

Department of Molecular Biology and Immunology, Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.

The over-expression of hyaluronidase has been observed in many types of cancer, suggesting that it may have utility for diagnosis. Here we present a technique for the detection of hyaluronidase using Fluorescence Correlation Spectroscopy (FCS). Hyaluronan macromolecules (HAs) have been heavily labeled with fluorescein amine resulting in strong self-quenching. In the presence of hyaluronidase, HA is cleaved into smaller, fluorescein-labeled fragments and the self-quenching is released. Such cleavage is manifested by the increased average diffusion rate of the HA fragments, increased concentration of individual, fluorescent HA fragments, and increased intensity. All three of these properties are monitored simultaneously throughout FCS measurements, both as a function of time and hyaluronidase concentration. The method we present provides a sensitive measure of hyaluronidase activity and requires extremely small amounts of the HA substrate.
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http://dx.doi.org/10.1016/j.jphotobiol.2012.07.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3461185PMC
November 2012

Properties of coatings on RFID p-Chips that support plasmonic fluorescence enhancement in bioassays.

Anal Bioanal Chem 2012 Nov 8;404(8):2223-31. Epub 2012 Sep 8.

Center for Commercialization of Fluorescence Technologies, Department of Molecular Biology and Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.

Microtransponders (RFID p-Chips) derivatized with silver island film (SIF) have previously seen success as a platform for the quantification of low-abundance biomolecules in nucleic acid based assays and immunoassays. In this study, we further characterized the morphology of the SIF as well as the polymer matrix enveloping it by scanning electron microscopy (SEM). The polymer was a two-layer silane-based matrix engulfing the p-Chip and SIF. Through a series of SEM and confocal fluorescence microscopy experiments, we found the depth of the polymer matrix to be 1-2 μm. The radiative effects of the SIF/polymer layer were assessed by fluorescence lifetime imaging (FLIM) of p-Chips coated with the polymer to which a fluorophore (Alexa Fluor 555) was conjugated. FLIM images showed an 8.7-fold increase in fluorescence intensity and an increased rate of radiative decay, the latter of which is associated with improved photostability and both of which are linked to plasmonic enhancement by the SIF. Plasmonic enhancement was found to extend uniformly across the p-Chip and, interestingly, to a depth of about 1.2 μm. The substantial depth of enhancement suggests that the SIF/polymer layer constitutes a three-dimensional matrix that is accessible to solvent and small molecules such as fluorescent dyes. Finally, we confirmed that no surface-enhanced Raman scattering is seen from the SIF/polymer combination. The analysis provides a possible mechanism by which the SIF/polymer-coated p-Chips allow a highly sensitive immunoassay and, as a result, leads to an improved bioassay platform.
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http://dx.doi.org/10.1007/s00216-012-6369-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3477286PMC
November 2012

FRET enhanced fluorescent nanodiamonds.

Curr Pharm Biotechnol 2014 ;14(13):1127-33

Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, TX 76129, USA.

Fluorescent nanodiamonds (FNDs) are one of the new and very promising biocompatible nanomaterials that can be used both as a fluorescence imaging agent and a highly versatile platform for controlled functionalization to target and deliver a wide spectrum of therapeutic agents. Among the remarkable fluorescence properties are excellent photostability, emission between 600-700nm, quantum yield of 1 and moderately long fluorescence lifetimes. However the low absorption cross section of fluorescent (N-V)(-) centers limits FNDs' brightness. In this work we show that an approach based on the Forster resonance energy transfer (FRET) may significantly enhance the fluorescence signal observed from a single ND. We demonstrate that organic dyes (fluorophores) attached to the FND surface can efficiently transfer the excitation energy to (N-V)(-) centers. Multiple dyes positioned in close proximity to the ND facile surface may serve as harvesting antennas transferring excitation energy to the fluorescent centers. We propose that, with the help of some of the functional groups present on the FND surface, we can either directly link flurophores or use scalable dendrimer chemistry to position many organic dyes at a calibrated distance. Also, the remaining multiple functional groups will be still available for particle targeting and drug delivery. This opens a new way for designing a new type of theranostics particles of ultrahigh brightness, high photostability, specific targeting, and high capacity for drug delivery.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3664135PMC
http://dx.doi.org/10.2174/138920101413140605110711DOI Listing
June 2015

Fluorescence detection of MMP-9. II. Ratiometric FRET-based sensing with dually labeled specific peptide.

Curr Pharm Biotechnol 2014 ;14(13):1134-8

Center of Commercialization of Fluorescence Technologies (CCFT), Dept. of Molecular Biology & Immunology, UNTHSC, Fort Worth, TX 76107, USA.

In our previous paper we showed that the MMP-9 enzyme recognizes a specific peptide sequence, Lys-Gly- Pro-Arg-Ser-Leu-Ser-Gly-Lys, and cleaves the peptide into two parts [1]. In this study, the peptide is labeled with two dyes, carboxyfluorescein (5-FAM) and Cy5. A highly efficient energy transfer of over 80% results in a dominant emission of Cy5 at ~670 nm with an excitation of 470 nm. Severance of the peptide by the MMP-9 enzyme eliminates Förster Resonance Energy Transfer (FRET) and strongly increases the fluorescence of the 5-FAM dye. In this manuscript we describe the strategy for a FRET-based method for MMP-9 enzyme detection. The basic aim is to apply a ratio-metric sensing technique in which a ratio of green/red fluorescence intensity is measured as a function of enzyme concentration. The ratio-metric method eliminates many experimental variables and enables accurate MMP-9 detection.
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http://dx.doi.org/10.2174/138920101413140605111109DOI Listing
June 2015

Lifetime-based sensing of the hyaluronidase using fluorescein labeled hyaluronic acid.

J Photochem Photobiol B 2012 Jan 20;106:69-73. Epub 2011 Oct 20.

Department of Molecular Biology and Immunology, Center for Commercialization of Fluorescence Technologies, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.

In this report we propose a lifetime-based sensing (LBS) for the detection of hyaluronidase (HA-ase). First, we heavily label hyaluronan macromolecules (HAs) with fluorescein amine. The fluorescein labeled HA (HA-Fl) has a weak fluorescence and short fluorescence lifetime due to an efficient self-quenching. Upon the addition of HA-ase, the brightness and lifetime of the sample increase. The cleavage of an HA macromolecule reduces the energy migration between fluorescein molecules and the degree of the self-quenching. A first order of the cleavage reaction depends on the amount of the HA-ase enzyme. We describe an HA-ase sensing strategy based on the lifetime changes of the fluorescein labeled HA in the presence of HA-ase. We demonstrate that the calibration of the sensing response is the same for the average lifetime as for a single exponential decay approximation, which significantly simplifies the analysis of the sensing measurements.
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http://dx.doi.org/10.1016/j.jphotobiol.2011.10.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3242895PMC
January 2012

The mechanical axes of the wrist are oriented obliquely to the anatomical axes.

J Bone Joint Surg Am 2011 Jan;93(2):169-77

Bioengineering Laboratory, Department of Orthopaedics, The Warren Alpert Medical School of Brown University and Rhode Island Hospital, 1 Hoppin Street, CORO West Suite 404, Providence, RI 02903, USA.

Background: the complex motions of the wrist are described in terms of four anatomical directions that are accomplished through the multiple articulations of the carpus. With minimal tendinous insertions, the carpus is primarily a passive structure. This emphasizes the importance of its mechanical properties, which few studies have examined to date. The purpose of the present study was to determine the mechanical properties of the wrist in twenty-four different directions of wrist motion.

Methods: the moment-rotation mechanical behavior of six fresh-frozen cadaver wrists was determined in four directions: flexion, extension, ulnar deviation, and radial deviation. Twenty other directions that were a combination of these anatomical directions were also studied. A custom-designed jig was interfaced with a standard materials testing system to apply unconstrained moments. Moments of ± 2 Nm were applied, and the moment-rotation data were recorded and analyzed to determine the neutral zone, range of motion, and stiffness values as well as the orientation of the envelope of these values.

Results: the envelope of wrist range-of-motion values was ellipsoidal in shape and was oriented obliquely (p < 0.001) to the direction of pure flexion-extension by a mean (and standard deviation) of 26.6° ± 4.4°. The largest wrist range of motion was a mean of 111.5° ± 10.2°, in the direction of ulnar flexion, 30° from pure flexion. The largest stiffness (mean, 0.4 Nm/deg) was in the direction of radial flexion, while the smallest stiffness (mean, 0.15 Nm/deg) was in the direction of ulnar flexion.

Conclusions: the mechanical axes of the wrist are oriented obliquely to the anatomical axes. The primary mechanical direction is one of radial extension and ulnar flexion, a direction along a path of the dart thrower's wrist motion.

Clinical Relevance: understanding the mechanical function of the wrist can aid clinical treatment decisions, arthroplasty, and implant designs. The findings of this study provide new evidence that the mechanical axes of the wrist are not collinear with the anatomical axes.
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http://dx.doi.org/10.2106/JBJS.I.01222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3016043PMC
January 2011