Controlled Release of Human Dental Pulp Stem Cell-Derived Exosomes from Hydrogels Attenuates Temporomandibular Joint Osteoarthritis.

Temporomandibular joint osteoarthritis (TMJOA) is a painful inflammatory condition that limits mouth opening. Cell-derived exosomes, which have anti-inflammatory effects, are emerging as a treatment for TMJOA. Injection of dental pulp stem cells (DPSCs), which secrete exosomes, can moderate tissue damage in a rat model of TMJOA.

Morphogen-driven differentiation is precluded by physical confinement in human iPSCs spheroids.

Introduction: Cell lineage specification is tightly associated with profound morphological changes in the developing human embryo, particularly during gastrulation. The interplay between mechanical forces and biochemical signals is poorly understood.

Methods: Here, we dissect the effects of biochemical cues and physical confinement on a 3D model based on spheroids formed from human induced pluripotent stem cells (hiPSCs).

Label-free 3D molecular imaging of living tissues using Raman spectral projection tomography.

The ability to image tissues in three dimensions (3D) with label-free molecular contrast at the mesoscale would be a valuable capability in biology and biomedicine. Here, we introduce Raman spectral projection tomography (RSPT) for volumetric molecular imaging with optical sub-millimeter spatial resolution. We have developed a RSPT imaging instrument capable of providing 3D molecular contrast in transparent and semi-transparent samples.

Injectable PEG Hydrogels with Tissue-Like Viscoelasticity Formed through Reversible Alendronate-Calcium Phosphate Crosslinking for Cell-Material Interactions.

Synthetic hydrogels provide controllable 3D environments, which can be used to study fundamental biological phenomena. The growing body of evidence that cell behavior depends upon hydrogel stress relaxation creates a high demand for hydrogels with tissue-like viscoelastic properties. Here, a unique platform of synthetic polyethylene glycol (PEG) hydrogels in which star-shaped PEG molecules are conjugated with alendronate and/or RGD peptides, attaining modifiable degradability as well as flexible cell adhesion, is created.

FRET Sensor-Modified Synthetic Hydrogels for Real-Time Monitoring of Cell-Derived Matrix Metalloproteinase Activity using Fluorescence Lifetime Imaging.

Matrix remodeling plays central roles in a range of physiological and pathological processes and is driven predominantly by the activity of matrix metalloproteinases (MMPs), which degrade extracellular matrix (ECM) proteins. Our understanding of how MMPs regulate cell and tissue dynamics is often incomplete as approaches are lacking and many strategies cannot provide high-resolution, quantitative measures of enzyme activity within tissue-like 3D microenvironments. Here, we incorporate a Förster resonance energy transfer (FRET) sensor of MMP activity into fully synthetic hydrogels that mimic many properties of the native ECM.