Detection and capture of breast cancer cells with photoacoustic flow cytometry.

According to the Centers for Disease Control and Prevention, breast cancer is the most common cancer and the second leading cause of cancer related deaths among women. Metastasis—the presence of secondary tumors caused by the spread of cancer cells via the circulatory or lymphatic systems—significantly worsens the prognosis of any breast cancer patient. A technique is developed to detect circulating breast cancer cells in human blood using a photoacoustic flow cytometry method.

Evanescent Field Based Photoacoustics: Optical Property Evaluation at Surfaces.

Here, we present a protocol to estimate material and surface optical properties using the photoacoustic effect combined with total internal reflection. Optical property evaluation of thin films and the surfaces of bulk materials is an important step in understanding new optical material systems and their applications. The method presented can estimate thickness, refractive index, and use absorptive properties of materials for detection.

Capture and Isolation of Circulating Melanoma Cells Using Photoacoustic Flowmetry.

Circulating tumor cells (CTCs) are those cells that separate from a solid tumor and spread through the blood or lymphatic systems. While there are many open questions concerning the biology of CTCs, there is mounting evidence that some of these cells go on to create secondary tumors in distant organs, thus enabling metastatic disease. Detection of CTCs may have clinical impact by providing prognostic information.

Photoacoustic measurement of refractive index of dye solutions and myoglobin for biosensing applications.

Current methods of determining the refractive index of chemicals and materials, such as ellipsometry and reflectometry, are limited by their inability to analyze highly absorbing or highly transparent materials, as well as the required prior knowledge of the sample thickness and estimated refractive index. Here, we present a method of determining the refractive index of solutions using the photoacoustic effect. We show that a photoacoustic refractometer can analyze highly absorbing dye samples to within 0.

Photoacoustic spectroscopy of β-hematin.

Malaria affects over 200 million individuals annually, resulting in 800,000 fatalities. Current tests use blood smears and can only detect the disease when 0.1-1% of blood cells are infected.

Capture of circulating tumor cells using photoacoustic flowmetry and two phase flow.

Melanoma is the deadliest form of skin cancer, yet current diagnostic methods are unable to detect early onset of metastatic disease. Patients must wait until macroscopic secondary tumors form before malignancy can be diagnosed and treatment prescribed. Detection of cells that have broken off the original tumor and travel through the blood or lymph system can provide data for diagnosing and monitoring metastatic disease.

Total internal reflection photoacoustic spectroscopy for the detection of β-hematin.

Evanescent field sensing methods are currently used to detect many different types of disease markers and biologically important chemicals such as the HER2 breast cancer receptor. Hinoue et al. used Total Internal Reflection Photoacoustic Spectroscopy (TIRPAS) as a method of using the evanescent field to detect an optically opaque dye at a sample interface.

Gold nanoparticle mediated detection of prostate cancer cells using photoacoustic flowmetry with optical reflectance.

The presence of circulating tumor cells in the bloodstream has been correlated with disease state in cancer patients. While we have successfully exploited melanin, the natural light absorber in melanoma cells, to induce photoacoustic waves for tumor cell detection, non-pigmented tumor cells do not have sufficient optical contrast for such a method. For example, breast, prostate and lung cancers lack intrinsic pigmentation and thus do not generate photoacoustic waves.

Plasma membrane integrity and survival of melanoma cells after nanosecond laser pulses.

Circulating tumor cells (CTCs) photoacoustic detection systems can aid clinical decision-making in the treatment of cancer. Interaction of melanin within melanoma cells with nanosecond laser pulses generates photoacoustic waves that make its detection possible. This study aims at: (1) determining melanoma cell survival after laser pulses of 6 ns at λ = 355 and 532 nm; (2) comparing the potential enhancement in the photoacoustic signal using λ = 355 nm in contrast with λ = 532 nm; (3) determining the critical laser fluence at which melanin begins to leak out from melanoma cells; and (4) developing a time-resolved imaging (TRI) system to study the intracellular interactions and their effect on the plasma membrane integrity.

Photoacoustic detection of melanoma micrometastasis in sentinel lymph nodes.

Melanoma is the deadliest form of skin cancer and has the fastest growth rate of all cancer types. Proper staging of melanoma is required for clinical management. One method of staging melanoma is performed by taking a sentinel node biopsy, in which the first node in the lymphatic drainage path of the primary lesion is removed and tested for the presence of melanoma cells.