Predicting Metastasis in Melanoma by Enumerating Circulating Tumor Cells Using Photoacoustic Flow Cytometry

Edgar, Robert H.; Tarhini, Ahmad A.; Sander, Cindy; Sanders, Martin; Cook, Justin; Viator, John A.

doi:10.1002/lsm.23286

Cited by 13 publications

(10 citation statements)

References 29 publications

(29 reference statements)

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“…We then validate their use in photoacoustic flow cytometry under ideal conditions, enabling future studies where bacterial identification will be performed in other media, including urine and blood. Efficacy of photoacoustic detection in blood has been previously shown in our cancer studies, where CTCs were detected from the blood of cancer patients [ 19 , 21 ].…”

Section: Introductionmentioning

confidence: 77%

“…We have used photoacoustics, or laser induced ultrasound, to generate acoustic responses in targets of interest for biosensing and other applications [ 15 , 16 , 17 ]. Photoacoustic flow cytometry has been used by several groups to detect circulating tumor cells (CTCs), both in vitro [ 18 , 19 , 20 , 21 ] and in vivo [ 22 , 23 ]. We have detected melanoma cells in blood samples by targeting their natural pigment with laser light, producing an acoustic signature that indicates the presence of the tumor cell.…”

Section: Introductionmentioning

confidence: 99%

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Photoacoustic Flow Cytometry Using Functionalized Microspheres for Selective Detection of Bacteria

et al. 2023

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Photoacoustic flow cytometry is a method to detect rare analytes in fluids. We developed photoacoustic flow cytometry to detect pathological cells in body fluids, such as circulating tumor cells or bacteria in blood. In order to induce specific optical absorption in bacteria, we use modified bacteriophage that precisely target bacterial species or subspecies for rapid identification. In order to reduce detection variability and to halt the lytic lifescycle that results in lysis of the bacteria, we attached dyed latex microspheres to the tail fibers of bacteriophage that retained the bacterial recognition binding sites. We tested these microsphere complexes using Salmonella enterica (Salmonella) and Escherichia coli (E. coli) bacteria and found robust and specific detection of targeted bacteria. In our work we used LT2, a strain of Salmonella, against K12, a strain of E. coli. Using Det7, a bacteriophage that binds to LT2 and not to K12, we detected an average of 109.3±9.0 of LT2 versus 2.0±1.7 of K12 using red microspheres and 86.7±13.2 of LT2 versus 0.3±0.6 of K12 using blue microspheres. These results confirmed our ability to selectively detect bacterial species using photoacoustic flow cytometry.

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Section: Introductionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Photoacoustic Flow Cytometry Using Functionalized Microspheres for Selective Detection of Bacteria

et al. 2023

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“…Our photoacoustic setup is based on our system used to detect circulating melanoma cells in blood. 13,26 PAFC has been described previously and was shown to be a robust method of detecting rare particles in dilute samples. The PAFC system was tested with phosphatebuffered saline (PBS) to demonstrate a level of background noise or variability.…”

Section: Methodsmentioning

confidence: 99%

“…11 PAFC has successfully been used to enumerate circulating tumor cells and has been shown to be a robust predictor of metastasis in melanoma. 12,13 Additionally, PAFC has been used successfully for the isolation of circulating tumor cells by several groups. 14,15 PAFC was invented to find rare, individual particles in complex environments.…”

Section: Introductionmentioning

confidence: 99%

Photoacoustic discrimination of antibiotic‐resistant and sensitive Staphylococcus aureus isolates

et al. 2021

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Objectives: Bacteremia is a serious and potentially lethal condition. Staphylococcus aureus is a leading cause of bacteremia and methicillin-resistant S. aureus (MRSA) accounts for more than a third of the cases. Compared to methicillinsensitive S. aureus, MRSA is more than twice as likely to be fatal. Furthermore, subpopulations of seemingly isogenic bacteria may exhibit a range of susceptibilities, often called heterogenous resistance. These heterogeneous antibioticresistant infections are often misdiagnosed as hospital-acquired secondary infections because there are no clinically used tests that can differentiate between homogeneous and heterogeneous antibiotic resistance. We describe the development and proof of concept of rapid bacterial identification using photoacoustic flow cytometry and labeled bacteriophages with the characterization and differentiation of heterogeneous antibiotic-resistant bacterial infections. Methods: In photoacoustic flow cytometry, pulsed laser light is delivered to a sample flowing past a focused transducer and particles that absorb laser light create an acoustic response. Optically labeled bacteriophage are added to a bacterial mixture that flows through the photoacoustic chamber. The presence of target bacteria is determined by bound labeled phage which are detected photoacoustically. Incubation of bacterial samples in the presence and absence of the antibiotic daptomycin creates a difference in bacterial cell numbers that is quantified using photoacoustic flow cytometry. Results: Four clinical isolates were tested in the presence and absence of daptomycin. Photoacoustic events for each isolate were recorded and compared to growth curves. Samples treated with daptomycin fell into three categories: resistant, susceptible, and heterogeneous resistant. Conclusions: Here we show a method to determine the presence of bacteria as a marker for bloodstream infection level and antibiotic sensitivity in less than 4 hours. Additionally, these results show an ability to identify heterogeneous resistant strains that are often misidentified.

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“…We have developed a photoacoustic method for detection of dilute particles in body fluids, in vitro (8,9). Much of this work has been used for detecting circulating tumor cells (CTCs), primarily melanoma cells, as their native optical absorber, melanin, makes them suitable for sensitive photoacoustic detection and enumeration.…”

Section: Staphylococcus Aureus From Ocular Infections Using Photoacou...mentioning

confidence: 99%

Differentiating methicillin resistant and susceptible Staphylococcus aureus from ocular infections using photoacoustic labeling

Edgar

Samson²,

Kowalski³

et al. 2023

Front. Med.

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IntroductionAntibiotic resistance in bacterial species constitutes a growing problem in the clinical management of infections. Not only does it limit therapeutic options, but application of ineffective antibiotics allows resistant species to progress prior to prescribing more effective treatment to patients. Methicillin resistance in Staphylococcus aureus is a major problem in clinical infections as it is the most common hospital acquired infection.MethodsWe developed a photoacoustic flow cytometer using engineered bacteriophage as probes for rapid determination of methicillin resistance in Staphylococcus aureus with thirteen clinical samples obtained from keratitis patients. This method irradiates cells under flow with 532 nm laser light and selectively generates acoustic waves in labeled bacterial cells, thus enabling detection and enumeration of them. Staphylococcus aureus isolates were classified from culture isolation as either methicillin resistant or susceptible using cefoxitin disk diffusion testing. The photoacoustic method enumerates bacterial cells before and after treatment with antibiotics. Decreasing counts of bacteria after treatment indicate susceptible strains. We quantified the bacterial cells in the treated and untreated samples.ResultsUsing k-means clustering on the data, we achieved 100% concordance with the classification of Staphylococcus aureus resistance using culture.DiscussionPhotoacoustics can be used to differentiate methicillin resistant and susceptible strains of bacteria from ocular infections. This method may be generalized to other bacterial species using appropriate bacteriophages and testing for resistance using other antibiotics.

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Predicting Metastasis in Melanoma by Enumerating Circulating Tumor Cells Using Photoacoustic Flow Cytometry

Cited by 13 publications

References 29 publications

Photoacoustic Flow Cytometry Using Functionalized Microspheres for Selective Detection of Bacteria

Photoacoustic Flow Cytometry Using Functionalized Microspheres for Selective Detection of Bacteria

Photoacoustic discrimination of antibiotic‐resistant and sensitive Staphylococcus aureus isolates

Differentiating methicillin resistant and susceptible Staphylococcus aureus from ocular infections using photoacoustic labeling

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