Concise Review: Fabrication, Customization, and Application of Cell Mimicking Microparticles in Stem Cell Science

Abstract

Stem and non‐stem cell behavior is heavily influenced by the surrounding microenvironment, which includes other cells, matrix, and potentially biomaterials. Researchers have been successful in developing scaffolds and encapsulation techniques to provide stem cells with mechanical, topographical, and chemical cues to selectively direct them toward a desired differentiation pathway. However, most of these systems fail to present truly physiological replications of the in vivo microenvironments that stem cells are typically exposed to in tissues. Thus, cell mimicking microparticles (CMMPs) have been developed to more accurately recapitulate the properties of surrounding cells while still offering ways to tailor what stimuli are presented. This nascent field holds the promise of reducing, or even eliminating, the need for live cells in select, regenerative medicine therapies, and diagnostic applications. Recent, CMMP‐based studies show great promise for the technology, yet only reproduce a small subset of cellular characteristics from among those possible: size, morphology, topography, mechanical properties, surface molecules, and tailored chemical release to name the most prominent. This Review summarizes the strengths, weaknesses, and ideal applications of micro/nanoparticle fabrication and customization methods relevant to cell mimicking and provides an outlook on the future of this technology. Moving forward, researchers should seek to combine multiple techniques to yield CMMPs that replicate as many cellular characteristics as possible, with an emphasis on those that most strongly influence the desired therapeutic effects. The level of flexibility in customizing CMMP properties allows them to substitute for cells in a variety of regenerative medicine, drug delivery, and diagnostic systems. Stem Cells Translational Medicine 2018;7:232–240

Engineering and Functionalization of Gelatin Biomaterials: From Cell Culture to Medical Applications

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Combining Stem Cells and Biomaterial Scaffolds for Constructing Tissues and Cell Delivery

“…Such particles are often combined with hydrogels [27] and electrospun scaffolds [28] to provide additional bioactivity and deliver additional factors when engineering complex tissues. Accordingly, drug-releasing particles on both the nano and micro scale can be used to control stem cell differentiation -both alone and in combination with other scaffold formulations [29]. Different combinations of drug-releasing particles can be incorporated into such systems to yield a multifunctional construct for promoting stem cell differentiation into specific types of tissues.…”

Concise Review: Stem Cell Therapy for Stroke Patients: Are We There Yet?

“…With the notion that stem cells may confer therapeutic effects via secreted substances, there is also a translational push favoring decellularized over cellularized compositions, and such pharmacologic‐like or cell‐free treatments may benefit from the translational Stroke Treatment Academic Industry Roundtable (STAIR) criteria toward achieving the neuroprotective drug's safety profile . Specific safety deliberations are necessary when using freshly harvested, cultured, or cryopreserved cells, naked, encapsulated, or extracellular matrix‐loaded cells, and novel delivery devices such as sustained, controlled, and highly regulated nanoparticles, exosomes, extracellular vesicles, microRNAs, mitochondria, and other cellular components . The once cell‐directed transplantation approach has been replaced with much sophisticated cell components that have expanded toward emerging therapies using innovative cell‐derivative and even cell‐free compositions that will require a unique set of safety outcome evaluations.…”