Rapid and steady concentration gradient generation platform for an antimicrobial susceptibility test

An antibiotic concentration gradient microfluidic device integrating surface-enhanced Raman spectroscopy for multiplex antimicrobial susceptibility testing

“…Although a microchamber can increase the number of sensing spots and reduce the required sample volume and assay time, it is a challenge to simultaneously generate multiple antibiotic concentrations for MIC determination in a single chip. The first method involves fabricating a series of parallel microchannels and introducing different antibiotic concentrations through different inlets 14,15 or the same antibiotic concentration into different microchamber sizes. 16 Another method is based on the laminar flow behavior of microfluidics.…”

Microfluidics for antibiotic susceptibility testing

“…96 A solution based on the classical microfluidic linear gradient generator 40 showed AST with bacteria growth measured by changes in turbidity within reaction chambers that were broader than the flow channel. 97 In another instance, 98 the linear antibiotic concentration gradient was formed by a flowing medium with antibiotic and a medium without antibiotic on two sides of a culturing chamber, similar to the classical “Death Galaxy” device by Austin et al 44 In this new solution, 98 bacteria grew within agar, which protected them from shear stress and from being washed away. The system was used for assessing bacterial growth in the presence of two antibiotics at different concentrations, which is advantageous as it allows for studies of antibiotic interactions, however the need for a syringe pump to be operating at a constant speed for the whole 6 h of measurement and the need for periodical refilling of media in device's reservoirs is limiting.…”

Microfluidic nanodevices for drug sensing and screening applications

“…It was achieved by introducing a serpentine mixing channel to the MSG to initiate the mixing of the laminar flow in a much shorter length, as depicted in Fig. 8 a ( Shi et al, 2019 ). In addition, different geometrical designs facilitate the mimicking of human organs for drug screening in microfluidic systems.…”

“…8 Representative examples of diverse geometries of different microfluidic platforms. (a) A concentration gradient generator-based microfluidic device and a wide range of flow rates, reproduced with permission from ( Shi et al, 2019 ), copyright 2019 Elsevier. (b) Schematic of branched, spiral, serpentine, and 3D-interconnected forms of microfluidic channels for developing vascularized tissue or organ models, reproduced with permission from ( Nie et al, 2018 ), copyright 2018 Wiley-VCH.…”