Biochemical detection of pediatric eosinophilic esophagitis using high wavenumber Raman endoscopy and stimulated Raman microscopy.

Eosinophilic esophagitis (EoE) is an immunoinflammatory condition of the esophagus characterized by an intense eosinophilic inflammation. Given its chronic and progressive course, EoE can lead to esophageal remodeling and dysphagia. Current diagnostic methods require repeated endoscopy to rate the severity of esophageal involvement and several biopsies of the esophageal mucosa for histopathologic confirmation of EoE, which can result in misdiagnosis and diagnostic delays.

Development and characterization of a combined fluorescence and spatial frequency domain imaging system for real-time dosimetry of photodynamic therapy.

Significance: Current methods of measuring dosimetry for photodynamic therapy (PDT) have proven to be inadequate in their inability to provide accurate, real-time, and spatially resolved monitoring without interrupting the PDT treatment.

Aim: Our goal was to develop and validate a combined treatment and dosimetry system capable of monitoring implicit and explicit dosimetry in real time during non-contact PDT.

Approach: By employing both fluorescence imaging and spatial frequency domain imaging (SFDI), designed with low-cost, off-the-shelf components, the combined imaging system would be able to provide information on the spatial distributions of photosensitizer concentrations, tissue oxygenation, and delivered light dose, all while monitoring the photobleaching dynamics of the photosensitizer.

Impact of scattering phase function and polarization on the accuracy of diffuse and sub-diffuse spatial frequency domain imaging.

Significance: Although spatial frequency domain imaging (SFDI) has been well characterized under diffuse optical conditions, tissue measurements made outside the diffuse regime can provide new diagnostic information. Before such measurements can become clinically relevant, however, the behavior of sub-diffuse SFDI and its effect on the accuracy of derived tissue parameters must be assessed.

Aim: We aim to characterize the impact that both the assumed scattering phase function (SPF) and the polarization state of the illumination light source have on the accuracy of SFDI-derived optical properties when operating under diffuse or sub-diffuse conditions, respectively.

Development of a Low-Cost Paper-Based Platform for Coffee Ring-Assisted SERS.

The need for highly sensitive, low-cost, and timely diagnostic technologies at the point of care is increasing. Surface-enhanced Raman spectroscopy (SERS) is a vibrational spectroscopic technique that is an advantageous technique to address this need, as it can rapidly detect analytes in small or dilute samples with improved sensitivity compared to conventional Raman spectroscopy. Despite the many advantages of SERS, one drawback of the technique is poor reproducibility due to variable interactions between nanoparticles and target analytes.

Measurement of rat and human tissue optical properties for improving the optical detection and visualization of peripheral nerves.

Peripheral nerve damage frequently occurs in challenging surgical cases resulting in high costs and morbidity. Various optical techniques have proven effective in detecting and visually enhancing nerves, demonstrating their translational potential for assisting in nerve-sparing medical procedures. However, there is limited data characterizing the optical properties of nerves in comparison to surrounding tissues, thus limiting the optimization of optical nerve detection systems.

Development of a platform for broadband, spectra-fitted, tissue optical phantoms.

Significance: Current methods of producing optical phantoms are incapable of accurately capturing the wavelength-dependent properties of tissue critical for many optical modalities.

Aim: We aim to introduce a method of producing solid, inorganic phantoms whose wavelength-dependent optical properties can be matched to those of tissue over the wavelength range of 370 to 950 nm.

Approach: The concentration-dependent optical properties of 20 pigments were characterized and used to determine combinations that result in optimal fits compared to the target properties over the full spectrum.

Simultaneous Exposure to Intracellular and Extracellular Photosensitizers for the Treatment of Staphylococcus aureus Infections.

Staphylococcus aureus is a serious threat to public health due to the rise of antibiotic resistance in this organism, which can prolong or exacerbate skin and soft tissue infections (SSTIs). Methicillin-resistant S. aureus is a Gram-positive bacterium and a leading cause of SSTIs.

Optimization of optical parameters for improved photodynamic therapy of Staphylococcus aureus using endogenous coproporphyrin III.

Background: It has recently been shown that endogenous photosensitization of Gram-positive bacteria is achieved through the accumulation of the heme precursor coproporphyrin III and not protoporphyrin IX, as was previously assumed. As previous studies have operated under this assumption, the efficacy of optimal targeting of the absorption peaks of coproporphyrin III has not been explored.

Methods: Staphylococcus aureus was endogenously photosensitized through the addition of either the small molecule VU0038882, aminolevulinic acid, or both.