Allergy Testing and Drug Screening on an ITO-Coated Lab-on-a-Disc

Abstract

A lab-on-a-disc (LOAD) is a centrifugal microfluidic set-up based on centrifugal force without using micro-pumps to drive reagents and cells to various chambers through channels and valves for reactions. A LOAD coated with conductive transparent indium tin oxide (ITO) for thermal control was developed to screen allergy-blocking agents. When the acridine orange (AO)-loaded KU-812 human basophilic cells were activated in the LOAD by stimuli, AO trapped in the cytoplasmic granules was released externally as an allergic mediator mimetic to report degranulation. This response was monitored by fluorescence when the released AO in supernatant had been transferred, with a higher spinning speed, from the reaction chamber to detection chamber in the LOAD where AO reacted with exogenous DNA. We report here the principles of the system and an improved LOAD set-up with the ITO-coated glass resistive microheater to run assays at 37 °C. By using this platform, we demonstrate here for the first time that triptolide, an active ingredient from the Chinese medicine herb Tripterygium wilfordii Hook f., was able to suppress the fMLP-mediated degranulation in basophils. This serves as an example how LOADs can be used to screen agents to alleviate symptoms of allergy.

Application of Microfluidics in Drug Development from Traditional Medicine

“…In the same vein, Ho Chin Kwok et al also used this reliance on telecentric forces to move agents and cells around in an experimental design. However, they combined this with the indium tin oxide (ITO) microheater pathway, they found a traditional drug ingredient (tretinoin) that effectively inhibits allergic reactions, as shown in Figure 18 [ 68 ]. Furthermore, in measuring antioxidant capacity, there is also a microfluidic technique paired with a novel instrument for peroxyoxalate chemiluminescence (PO-CL).…”

Prospects and Opportunities for Microsystems and Microfluidic Devices in the Field of Otorhinolaryngology

“…That LOAD platform demonstrated some advantages over the standard test, such as shorter analysis time, improved sensitivity, simple procedure, lower cost, and reduced consumption of samples and reagents ( Fig. 6A ) [ 57 , 58 ].…”

A novel tool for clinical diagnosis of allergy operating a microfluidic immunoaffinity basophil activation test technique

“…In another study, LOAD was coated with conductive transparent indium tin oxide, which can be used to control the temperature. Human KU812 cell line was stained with acridine orange and degranulation after fMLP activation was detected following incubation with an allergyblocking agent, triptolide [143]. A chip with flow cytometry properties analyzed rat basophilic leukemia cell line (RBL-2H3), and was used to look at single cell FceRI signaling [144].…”

“…To our knowledge, there are at present no other microfluidic techniques capable of capturing and stimulating human basophils from whole blood. Most microfluidic assays are developed using basophil cell line, such as the CD-based platform lab-on-a-disc (LOAD) [142,143] and the impedance measurements of the negative charge from degranulation in a microfluidic chip [147]. Surface plasmon resonance (SPR), detects changes in refractive index in captured cells and has been used to study the degranulation of captured human basophils from blood, but after prior purification steps [146].…”