Thursday 30 November 2023

Organ on a chip and DRAQs

Organ-on-a-chip (OOAC) technologies and DRAQs

DRAQ5™, DRAQfx™, DRAQ7™, DRAQ9™ and HypoxiTRAK™ offer a number of special benefits for the analysis of the improved physiological relevance organ-on-a-chip technologies (OOAC) or microphysiological systems (MPS).  The red excitation and the far-red fluorescence reduces the interference from sample autofluorescence and the improved excitation light penetration and signal fluorescence transmission, as a direct consequence of the longer wavelengths involved.

DRAQ7™, the far-red DNA-binding viability dye, has been widely demonstrated for the time-lapse reporting of cell death in a wide variety of OOAC platforms, of 2D and 3D cell geometries.  This is consistent with its cross-platform capabilities demonstrated on flow cytometers, imaging flow cytometers, fluorescence microscopy and high content screening platforms. DRAQ7™ breaks the problem of the use of homogeneous assays such as Alamar Blue, ATP, MTT to measure cell viability which all necessitate extra destructive processing of samples and cannot be applied in real-time / time-lapse.

DRAQ5™, the widely-used far-red, live-cell permeant DNA counterstain, is backed by 12,000+ publications across a wide range of applications.  Its major use is as an endpoint live-cell or fixed-cell counterstain and in addition to slide-based immunofluorescence microscopy has been widely utilised in OOAC imaging workflows.

Given the variety of platforms and scaffolds that are being employed it is important to have alternative chemistries for fixed-cell endpoint analyses.  Accordingly, using the same fluorescence Ex/Em settings one can choose between hydrophobic DRAQ5™ or hydrophilic DRAQfx™. This allows for easier switching between platform technologies, without having to re-design the analysis set-up.  

Segmentation of 3D objects can be challenging and to address this BioStatus has developed a non-toxic, log-term probe – DRAQ9™ - that can be used to define the cellularity of a 3D microtissue/spheroid/organoid and track its changes over many days, to enable automatic masking without the confounding aberrations of ECM protrusions and to follow cell migration.

A related fluorescent probe HypoxiTRAK™ is a novel means to report the response and accumulated experience of individual cells to hypoxia.  This far-red probe is otherwise non-toxic to cells and is only bioconverted to accumulate inside a cell when that cell experiences the paucity of dioxygen (below 3%; the probe’s direct competitor).  HypoxiTRAK is able to report on hypoxia experience over many days in 2D culture and 3D microtissues/organoids. 

You can purchase the products direct from BioStatus (and take advantage of our no-quibble, money-back guarantee) or from our carefully-selected channel partners. 

A selection of citations follows by product with disease/tissue and lead institution:

DRAQ5™ (most recent papers only)

Pamies et al. Altex 2017 Brain MPS Johns Hopkins Univ.

Scheinpflug et al. Lab Chip 2023  Bone scaffolds Greifswald Univ.

Vanderlaan et al. Lab on a Chip 2023 Islet-on-a-chip Purdue Univ.

Signore et al. Sens Biosens Res 2021 Gut-on-a-chip CNR-IMM, Lecce

Huebsch et al. Nat Biomed Eng 2022 Cardiac chip UC-Berkeley

Arakawa et al. Comms Biol 2023 Bile canaliculus Kanazawa Univ.

Hansen et al. Circ. Res. 2010 Eng. heart tissue Hamburg-Eppendorf Univ.

Zhang et al. Lab Chip 2022 Dental stem cells Hong Kong Univ.

Järvinen et al. Adv Funct Mater 2020 Hepatocytes (2 v 3D) Univ. Helsinki

Pieters et al. Biofabrication 2022 Adipose (3D) Univ. Toronto

Afshar et al. Sci Rep 2020 Skeletal muscle Univ. Toronto

Orellano et al. Adv Funct Mater 2023 Cell bioprinting Charité, Berlin

Amiri et al. Adv Sci 2021 Blood-Brain Barrier UC-Berkeley


Tran et al.  Transplantation 2023 Organ rejection Univ Hosp Geneva

Geyer et al. Front Immunol 2023 PDAC Mimetas

Law et al. Adv Sci 2022 Breast cancer Univ Tech Sydney

Miller et al. Tibtech 2020 Intestine JHU / U-WA

Boquet-Pujadas et al. Sci Adv 2022 Intestine Univ Paris Cité

Kopec et al. J Toxicol Sci 2021 Liver Pfizer

Bray et al. Front Bioeng Biotech 2019 Liver tumors QUT, Brisbane

Xue et al. Cell 2023 Tumorspheres Cypre, Inc.

Willi et al. Front Bioeng Biotech 2022 ex vivo intestinal FBRI, Roanoke

Miller et al. Neoplasia 2023 RCC on a chip U-WA


Edward et al. SLAS Conference 2020 Cancer spheroids BioStatus / Cardiff Univ.


Close & Johnston. SLAS Discovery 2022 HNC spheroids Pittsburgh Univ.