Impact of Four Common Hydrogels on Amyloid-β (Aβ) Aggregation and Cytotoxicity: Implications for 3D Models of Alzheimer's Disease.

The physiochemical properties of hydrogels utilized in 3D culture can be used to modulate cell phenotype and morphology with a striking resemblance to cellular processes that occur . Indeed, research areas including regenerative medicine, tissue engineering, cancer models, and stem cell differentiation have readily utilized 3D biomaterials to investigate cell biological questions. However, cells are only one component of this biomimetic milieu.

Protein folding and assembly in confined environments: Implications for protein aggregation in hydrogels and tissues.

In the biological milieu of a cell, soluble crowding molecules and rigid confined environments strongly influence whether the protein is properly folded, intrinsically disordered proteins assemble into distinct phases, or a denatured or aggregated protein species is favored. Such crowding and confinement factors act to exclude solvent volume from the protein molecules, resulting in an increased local protein concentration and decreased protein entropy. A protein's structure is inherently tied to its function.

Collagen hydrogel confinement of Amyloid-β (Aβ) accelerates aggregation and reduces cytotoxic effects.

Alzheimer's disease (AD) is the most common form of dementia and is associated with the accumulation of amyloid-β (Aβ), a peptide whose aggregation has been associated with neurotoxicity. Drugs targeting Aβ have shown great promise in 2D in vitro models and mouse models, yet preclinical and clinical trials for AD have been highly disappointing. We propose that current in vitro culture systems for discovering and developing AD drugs have significant limitations; specifically, that Aβ aggregation is vastly different in these 2D cultures carried out on flat plastic or glass substrates vs.

Direct, Real-Time Detection of Adenosine Triphosphate Release from Astrocytes in Three-Dimensional Culture Using an Integrated Electrochemical Aptamer-Based Sensor.

In this manuscript, we describe the development and application of electrochemical aptamer-based (E-AB) sensors directly interfaced with astrocytes in three-dimensional (3D) cell culture to monitor stimulated release of adenosine triphosphate (ATP). The aptamer-based sensor couples specific detection of ATP, selective performance directly in cell culture media, and seconds time resolution using squarewave voltammetry for quantitative ATP-release measurements. More specifically, we demonstrate the ability to quantitatively monitor ATP release into the extracellular environment after stimulation by the addition of calcium (Ca), ionomycin, and glutamate.