Influence of Halogen-Solvent Hydrogen Bonding on Gold Nanocluster Photoluminescence.

The influence of gold nanocluster-solvent interactions on nanostructure optical properties was determined. Using [Au(BINAP)X], where X = Cl or Br, as a model system, the dramatic influence of halogen-solvent hydrogen bonding on nanocluster optical properties was resolved. The creation of a nanocluster-solvent hydrogen-bond network yielded intense photoluminescence (PL) and an accompanying 2-fold reduction in vibration-mediated nonradiative decay rates.

Role of higher-order scattering in solutions to the forward and inverse optical-imaging problems in random media.

From analytical and numerical solutions that predict the scattering of diffuse photon density waves and from experimental measurements of changes in phase shift theta and ac amplitude demodulation M caused by the presence of single and double cylindrical heterogeneities, we show that second- and higher-order perturbations can affect the prediction of the propagation characteristics of diffuse photon density waves. Our experimental results for perfect absorbers in a lossless medium suggest that the performance of fast inverse-imaging algorithms that use first-order Born or Rytov approximations might have inherent limitations compared with inverse solutions that use iterative solutions of a linear perturbation equation or numerical solutions of the diffusion equation.

Sutureless ophthalmic surgery: a scaffold-enhanced bioadhesive technique.

Purpose: Bioadhesives have had limited use in ophthalmic surgery. Problems with these adhesives have included inadequate tensile strength and difficulty with their application to the tissue site. We evaluated a scaffold-enhanced cyanoacrylate bioadhesive composite as an alternative to sutures in ophthalmic surgery, including strabismus procedures.

A new technique of tissue repair for ophthalmic surgery.

Ophthalmic surgery currently utilizes suture materials to repair wounds created during eye operations. Although effective, suture-based techniques can result in complications that further impair the patient's vision, such as retinal detachment and scleral perforation associated with strabismus (eye muscle) surgery. Two techniques currently under development avoid sutures altogether, yielding similar strength results, reduced operating time, and simpler methods of repair.

Scaffold-enhanced albumin and n-butyl-cyanoacrylate adhesives for tissue repair: ex vivo evaluation in a porcine model.

An ex vivo study was conducted in a porcine model to compare the tensile strength of tissue samples repaired by three different repair methods: (i) scaffold-enhanced light-activated albumin protein solder, (ii) scaffold-enhanced n-butyl-cyanoacrylate adhesive, and (iii) conventional sutures. Biodegradable polymer scaffolds of controlled porosity were fabricated with poly(L-lactic-co-glycolic acid) (PLGA) and salt particles using a solvent-casting and particulate-leaching technique. Repairs were conducted on seventeen different tissues including the carotid, femoral, splenic, coronary, and pulmonary arteries, aorta, small intestine, ureter, sciatic nerve, spleen, atrium, kidney, muscle, skin, lung, liver and pancreas.

Effect of varying chromophores used in light-activated protein solders on tensile strength and thermal damage profile of repairs.

Clinical adoption of laser tissue welding (LTW) techniques has been beleaguered by problems associated with thermal damage of tissue and insufficient strength of the resulting tissue bond. The magnitude of these problems has been significantly reduced with the incorporation of indocyanine green (ICG)-doped protein solders into the LTW procedure to form a new technique known as laser tissue soldering (LTS). With the addition of ICG, a secondary concern has arisen relating to the potential harmful effects of the degradation products of the chromophore upon thermal denaturation of the protein solder with a laser.

Absorption properties of alternative chromophores for use in laser tissue soldering applications.

The feasibility of using alternative chromophores in laser tissue soldering applications was explored. Two commonly used chromophores, indocyanine green (ICG), and methylene blue (MB) were investigated, as well as three different food colorings: red #40 (RFC), blue #1 (BFC), and green consisting of yellow #5 and blue #1 (GFC). Three experimental studies were conducted: (i) The absorption profiles of the five chromophores, when diluted in deionized water and when bound to protein, were recorded; (ii) the effect of accumulated thermal dosages on the absorption profile of the chromophores was evaluated; and (iii) the stability of the absorption profiles of the chromophore-doped solutions when exposed to ambient light for extended time periods was measured.

Optimal visual perception and detection of oral cavity neoplasia.

The most common way to detect disease is by visual inspection of the suspect tissue. However, the human eye is not optimized for this task because the perceived spectrum of light is divided into three channels, all of which have overlapping spectral sensitivity curves. Here, we present new methods to optimize visually perceived contrast based on spectral differences between normal and abnormal tissue.

Improved vascular tissue fusion using new light-activated surgical adhesive on a canine model.

Newly developed light-activated surgical adhesives have been investigated as a substitute to traditional protein solders for vascular tissue fusion without the need for sutures. Canine femoral arteries (n = 14), femoral veins (n = 14), and carotid arteries (n = 10) were exposed, and a 0.3-0.

Optimal excitation wavelengths for in vivo detection of oral neoplasia using fluorescence spectroscopy.

There is no satisfactory mechanism to detect premalignant lesions in the upper aero-digestive tract. Fluorescence spectroscopy has potential to bridge the gap between clinical examination and invasive biopsy; however, optimal excitation wavelengths have not yet been determined. The goals of this study were to determine optimal excitation-emission wavelength combinations to discriminate normal and precancerous/cancerous tissue, and estimate the performance of algorithms based on fluorescence.

Characterization of the autofluorescence of polymorphonuclear leukocytes, mononuclear leukocytes and cervical epithelial cancer cells for improved spectroscopic discrimination of inflammation from dysplasia.

Fluorescence spectroscopy has the potential to improve the in vivo detection of intraepithelial neoplasias; however, the presence of inflammation can sometimes result in misclassifications. Inflammation is a common and important pathologic condition of epithelial tissues that can exist alone or in combination with neoplasia. It has not only been associated with the presence of cancer but also with the initiation of cancer by damage induced due to the oxidative activity of inflammatory cells.