Position along the nasal/temporal plane affects synaptic development by adult photoreceptors, revealed by micropatterning

Advances in microfluidic chips targeting toxic aggregation proteins for neurodegenerative diseases

Neurodegenerative diseases (NDs) are characterized by nervous system damage, often influenced by genetic and aging factors. Pathological analysis frequently reveals the presence of aggregated toxic proteins. The intricate and poorly understood origins of these diseases have hindered progress in early diagnosis and drug development. The development of novel in-vitro and in-vivo models could enhance our comprehension of ND mechanisms and facilitate clinical treatment advancements. Microfluidic chips are employed to establish three-dimensional culture conditions, replicating the human ecological niche and creating a microenvironment conducive to neuronal cell survival. The incorporation of mechatronic controls unifies the chip, cells, and culture medium optimizing living conditions for the cells. This study provides a comprehensive overview of microfluidic chip applications in drug and biomarker screening for neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, and amyotrophic lateral sclerosis. Our Lab-on-a-Chip system releases toxic proteins to simulate the pathological characteristics of neurodegenerative diseases, encompassing β-amyloid, α-synuclein, huntingtin, TAR DNA-binding protein 43, and Myelin Basic Protein. Investigating molecular and cellular interactions in vitro can enhance our understanding of disease mechanisms while minimizing harmful protein levels and can aid in screening potential therapeutic agents. We anticipate that our research will promote the utilization of microfluidic chips in both fundamental research and clinical applications for neurodegenerative diseases.

Microfluidic and Microscale Assays to Examine Regenerative Strategies in the Neuro Retina

Bioengineering systems have transformed scientific knowledge of cellular behaviors in the nervous system (NS) and pioneered innovative, regenerative therapies to treat adult neural disorders. Microscale systems with characteristic lengths of single to hundreds of microns have examined the development and specialized behaviors of numerous neuromuscular and neurosensory components of the NS. The visual system is comprised of the eye sensory organ and its connecting pathways to the visual cortex. Significant vision loss arises from dysfunction in the retina, the photosensitive tissue at the eye posterior that achieves phototransduction of light to form images in the brain. Retinal regenerative medicine has embraced microfluidic technologies to manipulate stem-like cells for transplantation therapies, where de/differentiated cells are introduced within adult tissue to replace dysfunctional or damaged neurons. Microfluidic systems coupled with stem cell biology and biomaterials have produced exciting advances to restore vision. The current article reviews contemporary microfluidic technologies and microfluidics-enhanced bioassays, developed to interrogate cellular responses to adult retinal cues. The focus is on applications of microfluidics and microscale assays within mammalian sensory retina, or neuro retina, comprised of five types of retinal neurons (photoreceptors, horizontal, bipolar, amacrine, retinal ganglion) and one neuroglia (Müller), but excludes the non-sensory, retinal pigmented epithelium.

Recent progress in translational engineered in vitro models of the central nervous system

The complexity of the human brain poses a substantial challenge for the development of models of the CNS. Current animal models lack many essential human characteristics (in addition to raising operational challenges and ethical concerns), and conventional in vitro models, in turn, are limited in their capacity to provide information regarding many functional and systemic responses. Indeed, these challenges may underlie the notoriously low success rates of CNS drug development efforts. During the past 5 years, there has been a leap in the complexity and functionality of in vitro systems of the CNS, which have the potential to overcome many of the limitations of traditional model systems. The availability of human-derived induced pluripotent stem cell technology has further increased the translational potential of these systems. Yet, the adoption of state-of-the-art in vitro platforms within the CNS research community is limited. This may be attributable to the high costs or the immaturity of the systems. Nevertheless, the costs of fabrication have decreased, and there are tremendous ongoing efforts to improve the quality of cell differentiation. Herein, we aim to raise awareness of the capabilities and accessibility of advanced in vitro CNS technologies. We provide an overview of some of the main recent developments (since 2015) in in vitro CNS models. In particular, we focus on engineered in vitro models based on cell culture systems combined with microfluidic platforms (e.g. 'organ-on-a-chip' systems). We delve into the fundamental principles underlying these systems and review several applications of these platforms for the study of the CNS in health and disease. Our discussion further addresses the challenges that hinder the implementation of advanced in vitro platforms in personalized medicine or in large-scale industrial settings, and outlines the existing differentiation protocols and industrial cell sources. We conclude by providing practical guidelines for laboratories that are considering adopting organ-on-a-chip technologies.

Microfluidic device-assisted etching of p-HEMA for cell or protein patterning

The construction of biomaterials with which to limit the growth of cells or to limit the adsorption of proteins is essential for understanding biological phenomena. Here, we describe a novel method to simply and easily create thin layers of poly (2-hydroxyethyl methacrylate) (p-HEMA) for protein and cellular patterning via etching with ethanol and microfluidic devices. First, a cell culture surface or glass coverslip is coated with p-HEMA. Next, a polydimethylsiloxane (PDMS) microfluidic is placed onto the p-HEMA surface, and ethanol is aspirated through the device. The PDMS device is removed, and the p-HEMA surface is ready for protein adsorption or cell plating. This method allows for the fabrication of 0.3 µm thin layers of p-HEMA, which can be etched to 10 µm wide channels. Furthermore, it creates regions of differential protein adhesion, as shown by Coomassie staining and fluorescent labeling, and cell adhesion, as demonstrated by C2C12 myoblast growth. This method is simple, versatile, and allows biologists and bioengineers to manipulate regions for cell culture adhesion and growth. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:243-248, 2018.

Compartmentalized Microfluidic Platforms: The Unrivaled Breakthrough of In Vitro Tools for Neurobiological Research

Microfluidic technology has become a valuable tool to the scientific community, allowing researchers to study fine cellular mechanisms with higher variable control compared with conventional systems. It has evolved tremendously, and its applicability and flexibility made its usage grow exponentially and transversely to several research fields. This has been particularly noticeable in neuroscience research, where microfluidic platforms made it possible to address specific questions extending from axonal guidance, synapse formation, or axonal transport to the development of 3D models of the CNS to allow pharmacological testing and drug screening. Furthermore, the continuous upgrade of microfluidic platforms has allowed a deeper study of the communication occurring between different neuronal and glial cells or between neurons and other peripheral tissues, both in physiological and pathological conditions. Importantly, the evolution of microfluidic technology has always been accompanied by the development of new computational tools addressing data acquisition, analysis, and modeling.

A Versatile Method of Patterning Proteins and Cells

Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning techniques work well only with simple shapes, small areas and selected bio-materials. This article describes a method to distribute cell suspensions as well as substrate solutions into complex, long, closed (dead-end) polydimethylsiloxane (PDMS) microchannels using negative pressure. This method enables researchers to pattern multiple substrates including fibronectin, collagen, antibodies (Sal-1), poly-D-lysine (PDL), and laminin. Patterning of substrates allows one to indirectly pattern a variety of cells. We have tested C2C12 myoblasts, the PC12 neuronal cell line, embryonic rat cortical neurons, and amphibian retinal neurons. In addition, we demonstrate that this technique can directly pattern fibroblasts in microfluidic channels via brief application of a low vacuum on cell suspensions. The low vacuum does not significantly decrease cell viability as shown by cell viability assays. Modifications are discussed for application of the method to different cell and substrate types. This technique allows researchers to pattern cells and proteins in specific patterns without the need for exotic materials or equipment and can be done in any laboratory with a vacuum.