In Situ Detection of Hydrogen Sulfide in 3D-Cultured, Live Prostate Cancer Cells Using a Paper-Integrated Analytical Device

Abstract

In this study, a paper-integrated analytical device that combined a paper-based colorimetric assay with a paper-based cell culture platform was developed for the in situ detection of hydrogen sulfide (H2S) in three-dimensional (3D)-cultured, live prostate cancer cells. Two kinds of paper substrates were fabricated using a simple wax-printing methodology to form the cell culture and detection zones, respectively. LNCaP cells were seeded directly on the paper substrate and grown in the paper-integrated analytical device. The cell viability and H2S production of LNCaP cells were assessed using a simple water-soluble tetrazolium salt colorimetric assay and H2S-sensing paper, respectively. The H2S-sensing paper showed good sensitivity (sensitivity: 6.12 blue channel intensity/μM H2S, R2 = 0.994) and a limit of quantification of 1.08 μM. As a result, we successfully measured changes in endogenous H2S production in 3D-cultured, live LNCaP cells within the paper-integrated analytical device while varying the duration of incubation and substrate concentration (L-cysteine). This paper-integrated analytical device can provide a simple and effective method to investigate H2S signaling pathways and drug screening in a 3D culture model.

Development of Lateral Flow Test-System for the Immunoassay of Dibutyl Phthalate in Natural Waters

“…Therefore, the pre-incubated LFIA format was applied in the work. The obtained test strips were processed as described in Section 2.2.5 with image conversion to grayscale, but there are other ways to process data [ 51 , 52 ].…”

Simple and Sensitive Detection of Bacterial Hydrogen Sulfide Production Using a Paper-Based Colorimetric Assay

“…Color changes in this paper were firstly confirmed with naked eyes and the image was subsequently obtained using an Epson scanner (Perfection V700 Photo flatbed scanner, Seiko Epson, Nagano, Japan). The blue channel intensity of the circular area (4.5 mm in diameter) on each detection zone was measured using ImageJ (National Institutes of Health, Bethesda, MD, USA) [ 21 , 22 ]. All values of the blue channel intensity were displayed as corrected blue channel intensity by subtracting the measured value on the detection zone from the intensity of blank zone in the Ag/Nafion/PVP-coated paper.…”

“…This paper assay, fabricated with a 96-well microplate type, possessed good sensitivity, high selectivity, and good stability, as well as excellent reproducibility. Moreover, we successfully detected H 2 S from 3D-culture, live cancer cells using a H 2 S sensing paper with 4 circles which was modified to fit the paper-integrated analytical device [ 22 ].…”

Cytotoxicity evaluation of sodium lauryl sulfate in a paper-based 3D cell culture system

“…To evaluate cell cytotoxicity on the paper-based 3D cell culture platform, the EZ-CyTox colorimetric cell viability assay solution was administered directly to the paper, and the changes in color intensity of the cell paper were analyzed quantitatively using an Epson scanner and ImageJ software, as described previously. 33 Briefly, after the images were split into red, green, and blue channels, the blue channel intensity of the whole area of each cell zone was analyzed to minimize the deviation between each paper. The change in blue channel intensity was defined as the blue channel intensity of the blank zone minus that of the cell zone.…”