Successful meeting in Vancouver. Looking forward to seeing you in Advanced Photonics 2017 in New Orleans.

By Howard Lee | Posted: 25 July 2016

It is great to attend a meeting with specific focus on certain topics as Advanced Photonics, since it is... 

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The Binding Finding of a Fluorescence Lifetime

By Ken Tichauer | Posted: 27 April 2014

In this afternoon’s session on Luminescence and Absorption on Cellular and Tissue Levels, Prof. Victor Chernomordik gave an overview of the extensive work he and his colleagues have been undertaking to make fluorescence molecular imaging more quantitative. Much of their work has focused specifically on how to quantify human epidermal growth factor receptor 2 (HER2) concentrations (a key receptor of interest in breast cancer) using kinetic models, and they have a number of publications in this area that I urge you to check out;1-5 however, what I was most intrigued by was there recent results demonstrating a dependence of fluorescence lifetime on the binding state of a targeted fluorescent tracer. In simpler terms, what they found was that the timing characteristics of fluorescence emission was significantly different depending on whether their fluorescent tracer was bound to the target of interest or not.6,7

This offers their group a window into separating non-specific uptake of a tracer, a major problem in conventional molecular imaging of tumors, from the more interesting bound fraction of the targeted tracer. Moreover, for reversible binding tracers (tracers that can dissociate from there targeted molecule), the ratio of the bound fraction of a tracer to the unbound fraction of tracer is directly proportional to the concentration of the targeted biomolecule.8 Therefore, as Prof. Chernomordik and his colleagues unearth the exact relationship between bound fraction and fluorescence lifetime, there is a clear pathway forward to using this approach to directly quantify HER2 concentration, something that is impossible to do with other conventional single tracer approaches in tumors.9

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The recent evolution of biomedical optics in one graphic*

By Kyle Quinn | Posted: 27 March 2014


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Salt and Pepper (Noise): Key Ingredients for Imaging Blood Flow

By Ken Tichauer | Posted: 25 March 2014

We’ve all experienced that “salt-and-pepper”, or white noise when our favorite television show cuts out on us. Well it turns out that similar “speckle” patterns are also seen when projecting laser light onto biological tissue, owing to interference patterns of the monochromatic light source. Now you might say, “so what!” and that’s probably what most would say. However, in the early 1980’s Fercher and Brier realized that movement of blood could disturb the laser speckle pattern, and this disturbance could be used to estimate blood flow [1].

In the decades following this breakthrough, Laser Speckle Imaging has been employed to visualize blood flow in the skin [2], the retina [3], and brain [4]. To date there are over 600 published articles that have included biomedical applications of Speckle Imaging. Why so popular? There are certainly many other approaches available for monitoring blood flow such as Doppler ultrasound, laser Doppler, and a slew of dynamic contrast enhanced imaging modalities. However, none of these approaches can offer the exquisite temporal resolution (milliseconds), and spatial resolution (10s of microns) that can be attained by Laser Speckle Imaging. And nowhere have these advantages been used to greater benefit than in the study of “neurovascular coupling”, which necessitates the ability to resolve the interplay between neuronal activity and blood delivery in the brain at the millisecond and micron resolution scales only offered by Speckle Imaging.

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Day 1: Seeing Order in Disorder

By David Norris | Posted: 6 March 2014

Greetings from Washington, DC, and the OSA Controlled Light Propagation Incubator meeting! Hosted by Tom Bifano and Jerome Mertz, Boston University, USA; Sylvain Gigan, Institut Langevin, France; and Allard Mosk, University of Twente, Netherlands; today’s event brings leading researchers from the fields of biological imaging and adaptive optics together with partners from industry and government for a candid discussion of the technological breakthroughs, challenges, and goals that have materialized in the past few years.  This is the eleventh meeting in the OSA’s Incubator series, which was established in 2009 as a way to promote the growth and development of nascent fields within the broader optics and photonics research community.

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How to fit a laser-scanning microscope into a 2mm diameter tube

By Kyle Quinn | Posted: 28 February 2014

Optical microscopy can provide high-resolution images of cellular morphology and matrix organization, which can be utilized to diagnose disease or trauma. However, achieving an adequate signal-to-noise ratio at imaging depths exceeding 1mm is very challenging.  As a result, the initial clinical applications for optical microscopy techniques have largely focused on skin pathology.  One approach to unlocking a wider spectrum of clinical applications for biomedical optics is miniaturizing the distal end of microscopes into endoscopic probes.

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Pushing the limits of imaging resolution and penetration depth

By Kyle Quinn | Posted: 28 February 2014

The development of labeling techniques capable of providing customizable molecular specificity has made optical microscopy a fundamental technique in the biomedical research, and the standard compound microscope remains a fixture in just about any clinic or biomedical lab. The popularity of optical microscopy was also driven by the ability to provide resolution at the cellular level that traditional clinical imaging modalities (e.g. ultrasound, x-ray CT, and MRI) simply cannot meet. The finer structural details of biological tissues were further elucidated through the development of transmission electron microscopy, which enabled unparalleled views at the scale of proteins and molecules. However, like all imaging technologies, there is a tradeoff between imaging resolution and penetration depth, and electron microscopy has extremely limited penetration depth.

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It takes blood, sweat, and SERS to image single cells

By Ken Tichauer | Posted: 20 February 2014

Throw out those old dusty fluorescent molecules and welcome in the next generation of optical contrast agents. SERS (Surface Enhanced Raman Scattering/Spectroscopy) nanoparticles are sophisticated new contrast agents that offer some distinct advantages over conventional fluorescent molecules for investigating molecular biology.

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Where would biomedicine be without optics?

By Kyle Quinn | Posted: 10 February 2014

Much of the emphasis in biomedical optics research has been placed on the clinical translation of our technologies -- and rightfully so!  As my fellow blogger Dr. Ken Tichauer indicates, the potential impact in the clinic is great and the future remains bright.  But as we gear up for OSA BIOMED 2014 in Miami, I will be excited to learn about some of the latest applications in basic science research where biomedical optics continues to play a key role. The field of optics has provided researchers advanced tools that are needed in a variety of other disciplines to optimize complex laboratory protocols, to elucidate the underlying mechanisms of disease, and to speed the preclinical development of novel therapies. Optogenetics


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Photoimmunotherapy (PIT) busts open the doors for drug delivery

By Ken Tichauer | Posted: 6 February 2014

Over the last decade alone, it is estimated that over $200 billion has been spent just by governments to fund cancer research [1]. Despite this enormous investment, the recently released 2014 World Heath Organization (WHO) Cancer Report suggests that cancer incidence rates and deaths from cancer are on the rise, both in more developed and less developed nations.

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Beginning of a new era? Recent advances in biomedical optics light the way to long-awaited clinical translation

By Ken Tichauer | Posted: 29 January 2014

For decades biomedical optics has been touted as an ideal tool for diagnosing, monitoring and/or treating a vast array of health conditions owing to low-cost instrumentation, use of non-ionizing radiation, and incomparable sensitivity. All great characteristics; nonetheless, adoptions of optical devices in the clinic have been few and far-between. One could blame regulations, the high cost of clinical trials, and provider inertia; but these hurdles would be behind us if the optical approaches on health and healthcare costs made more more significant impact. We're not there yet.

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Silk or Polyester? How Optics Can Help Determine an Answer

By Miaochan Zhi | Posted: 29 January 2013

I love silk.  Many clothes in my wardrobe are made of 100% silk.  This is an extension of my love of all things natural. Also, it is due to the fact that I lived in Hangzhou, China which is very famous for silk.

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