Extra short incubation microfluidic assisted – fluorescence in situ hybridization (ESIMA-FISH)

Fluorescence in situ hybridization (FISH) is a powerful technique for evaluating the HER2 gene status in breast cancer specimen (1). However, most of FISH assays currently used in clinical laboratories are expensive and require long experimental time, up to two days with an overnight incubation (2). Indeed, despite the development of faster FISH probes (HER2 IQFISH pharmDxTM from DAKO, Denmark) cutting the assay time to one day (3), the cost of these new probes is still high (more than 200$/test) and impedes the dissemination of this technique. In this study, we present the extra short incubation microfluidic assisted- fluorescence in situ hybridization (ESIMA-FISH) technique that uses microfluidics to improve FISH for HER2 assessment in breast cancer samples. ESIMA-FISH requires a very short incubation time (35 minutes) and uses 4-fold less probe solution per test. The system is based on a microfluidic chip, developed in our laboratory (4), that is clamped against a microscope slide containing a breast cancer tissue specimen (figure 1). A fluorescent DNA probe solution, specific to the target DNA, is then applied to the tissue section within a thin chamber using the microfluidic system. The probe solution used is obtained by diluting 4 times the standard HER2 IQFISH pharmDxTM probe solution (DAKO, Denmark). Oscillating flows can then be implemented using syringe pumps to improve the delivery of the probe to the tissue. Thanks to this hydrodynamic enhancement of mass transport, the probe-target hybridization efficiency is increased, resulting in overall reductions in the cost and duration of the assay. To validate the ESIMA-FISH technique, several tissue specimens were blindly tested with ESIMA-FISH and standard IQFISH. The results from these two techniques were comparable (figure 2, 3), supporting the possibility of a future clinical use of ESIMA-FISH

Development and Characterization of PEDOT:PSS/Alginate Soft Microelectrodes for Application in Neuroprosthetics

Reducing the mechanical mismatch between the stiffness of a neural implant and the softness of the neural tissue is still an open challenge in neuroprosthetics. The emergence of conductive hydrogels in the last few years has considerably widened the spectrum of possibilities to tackle this issue. Nevertheless, despite the advancements in this field, further improvements in the fabrication of conductive hydrogel-based electrodes are still required. In this work, we report the fabrication of a conductive hydrogel-based microelectrode array for neural recording using a hybrid material composed of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), and alginate. The mechanical properties of the conductive hydrogel have been investigated using imaging techniques, while the electrode arrays have been electrochemically characterized at each fabrication step, and successfully validated both in vitro and in vivo. The presence of the conductive hydrogel, selectively electrodeposited onto the platinum microelectrodes, allowed achieving superior electrochemical characteristics, leading to a lower electrical noise during recordings. These findings represent an advancement in the design of soft conductive electrodes for neuroprosthetic applications

Development and characterization of PEDOT:PSS/alginate soft microelectrodes for application in neuroprosthetics

Reducing the mechanical mismatch between the stiffness of a neural implant and the softness of the neural tissue is still an open challenge in neuroprosthetics. The emergence of conductive hydrogels in the last few years has considerably widened the spectrum of possibilities to tackle this issue. Nevertheless, despite the advancements in this field, further improvements in the fabrication of conductive hydrogel-based electrodes are still required. In this work, we report the fabrication of a conductive hydrogel-based microelectrode array for neural recording using a hybrid material composed of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), and alginate. The mechanical properties of the conductive hydrogel have been investigated using imaging techniques, while the electrode arrays have been electrochemically characterized at each fabrication step, and successfully validated both in vitro and in vivo. The presence of the conductive hydrogel, selectively electrodeposited onto the platinum microelectrodes, allowed achieving superior electrochemical characteristics, leading to a lower electrical noise during recordings. These findings represent an advancement in the design of soft conductive electrodes for neuroprosthetic applications