Miniaturized multicolor fluorescence imaging system integrated with a PDMS light-guide plate for biomedical investigation

Miniaturized fluorescence imaging systems are promising platforms that overcome the limited use of conventional microscopes in the biomedical field.However,there are physical limitations for multicolor fluorescence imaging in existing miniaturized imaging systems because multiple filters have to be integrated into a small structure.Here,we present a miniaturized multicolor fluorescence imaging system integrated with single polydimethylsiloxane(PDMS)light-guide plate(LGP)for multicolor fluorescence imaging.The PDMS LGP allows guiding the transmitted light from the light source only to the fluorescent samples regardless of the wavelength of the light source.Thus,our system is capable of multicolor fluorescence imaging without multiple filters that block the excitation light.We demonstrated the usability of our system in the biomedical field by observing green-and red-labeled cells in the incubator.Our proposed system can be used in a wide range of applications for studies that require multicolor fluorescence imaging in the biomedical field.

A MEMS ultrasound stimulation system for modulation of neural circuits with high spatial resolution in vitro

Neuromodulation by ultrasound has recently received attention due to its noninvasive stimulation capability for treating brain diseases.Although there have been several studies related to ultrasonic neuromodulation,these studies have suffered from poor spatial resolution of the ultrasound and low repeatability with a fixed condition caused by conventional and commercialized ultrasound transducers.In addition,the underlying physics and mechanisms of ultrasonic neuromodulation are still unknown.To determine these mechanisms and accurately modulate neural circuits,researchers must have a precisely controllable ultrasound transducer to conduct experiments at the cellular level.Herein,we introduce a new MEMS ultrasound stimulation system for modulating neurons or brain slices with high spatial resolution.The piezoelectric micromachined ultrasonic transducers(pMUTs)with small membranes(submm membranes)generate enough power to stimulate neurons and enable precise modulation of neural circuits.We designed the ultrasound transducer as an array structure to enable localized modulation in the target region.In addition,we integrated a cell culture chamber with the system to make it compatible with conventional cell-based experiments,such as in vitro cell cultures and brain slices.In this work,we successfully demonstrated the functionality of the system by showing that the number of responding cells is proportional to the acoustic intensity of the applied ultrasound.We also demonstrated localized stimulation capability with high spatial resolution by conducting experiments in which cocultured cells responded only around a working transducer.

Foldable three dimensional neural electrode arrays for simultaneous brain interfacing of cortical surface and intracortical multilayers

Challenges in the understanding of three-dimensional(3D)brain networks by simultaneously recording both surface and intracortical areas of brain signals remain due to the difficulties of constructing mechanical design and spatial limitations of the implanted sites.Here,we present a foldable and flexible 3D neural prosthetic that facilitates the 3D mapping of complex neural circuits with high spatiotemporal dynamics from the intracortical to cortical region.This device is the tool to map the 3D neural transmission through sophisticatedly designed four flexible penetrating shanks and surface electrode arrays in one integrated system.We demonstrate the potential possibilities of identifying correlations of neural activities from the intracortical area to cortical regions through continuous monitoring of electrophysiological signals.We also exploited the structural properties of the device to record synchronized signals of single spikes evoked by unidirectional total whisker stimulation.This platform offers opportunities to clarify unpredictable 3D neural pathways and provides a next-generation neural interface.