Methods to achieve tissue-mimetic physicochemical properties in hydrogels for regenerative medicine and tissue engineering.

Hydrogels are water-swollen polymeric matrices with properties that are remarkably similar in function to the extracellular matrix. For example, the polymer matrix provides structural support and adhesion sites for cells in much of the same way as the fibers of the extracellular matrix. In addition, depending on the polymer used, bioactive sites on the polymer may provide signals to initiate certain cell behavior.

Using biomaterials to improve mesenchymal stem cell therapies for chronic, nonhealing wounds.

Historically, treatment of chronic, nonhealing wounds has focused on managing symptoms using biomaterial-based wound dressings, which do not adequately address the underlying clinical issue. Mesenchymal stem cells (MSCs) are a promising cell-based therapy for the treatment of chronic, nonhealing wounds, yet inherent cellular heterogeneity and susceptibility to death during injection limit their clinical use. Recently, researchers have begun to explore the synergistic effects of combined MSC-biomaterial therapies, where the biomaterial serves as a scaffold to protect the MSCs and provides physiologically relevant physicochemical cues that can direct MSC immunomodulatory behavior.

Liquid Crystal Nanoparticle Conjugates for Scavenging Reactive Oxygen Species in Live Cells.

The elevated intracellular production of or extracellular exposure to reactive oxygen species (ROS) causes oxidative stress to cells, resulting in deleterious irreversible biomolecular reactions (e.g., lipid peroxidation) and disease progression.

Recent Advances in Bioorthogonal Click Chemistry for Biomedical Applications.

Bioorthogonal click chemistry, first introduced in the early 2000s, has become one of the most widely used approaches for designing advanced biomaterials for applications in tissue engineering and regenerative medicine, due to the selectivity and biocompatibility of the associated reactants and reaction conditions. In this review, we present recent advances in utilizing bioorthogonal click chemistry for the development of three-dimensional, biocompatible scaffolds and cell-encapsulated biomaterials. Additionally, we highlight recent examples using these approaches for biomedical applications including drug delivery, imaging, and cell therapy and discuss their potential as next generation biomaterials.

Sensing Nitric Oxide in Cells: Historical Technologies and Future Outlook.

Nitric oxide (NO) is a critical cell signaling molecule with important roles in both normal cellular physiology and pathology. Over the past 20 years, multiple sensing modalities have been developed for the intracellular synthesis (endogenous) and release (exogenous) of NO. In this review, we survey the historical progression of NO sensing platforms, highlight the current state of the art, and offer a forward-looking view of how we expect the field of NO sensing to develop in the context of recent advances in bio-nanotechnology and nanoscale cellular biosensors.

Recent Progress in Bioconjugation Strategies for Liposome-Mediated Drug Delivery.

In nanoparticle (NP)-mediated drug delivery, liposomes are the most widely used drug carrier, and the only NP system currently approved by the FDA for clinical use, owing to their advantageous physicochemical properties and excellent biocompatibility. Recent advances in liposome technology have been focused on bioconjugation strategies to improve drug loading, targeting, and overall efficacy. In this review, we highlight recent literature reports (covering the last five years) focused on bioconjugation strategies for the enhancement of liposome-mediated drug delivery.

Inducing mesenchymal stem cell attachment on non-cell adhesive hydrogels through click chemistry.

We introduce an innovative approach to adhere mesenchymal stem cells (MSCs) to a hydrogel scaffold by nucleating adhesion through strain-promoted click chemistry. This method yields a significant increase in cell viability compared to non-functionalized and RGD peptide functionalized hydrogels, providing a promising alternative to traditional biomaterials cell attachment approaches.

Nanoparticle-Mediated Visualization and Control of Cellular Membrane Potential: Strategies, Progress, and Remaining Issues.

The interfacing of nanoparticle (NP) materials with cells, tissues, and organisms for a range of applications including imaging, sensing, and drug delivery continues at a rampant pace. An emerging theme in this area is the use of NPs and nanostructured surfaces for the imaging and/or control of cellular membrane potential (MP). Given the important role that MP plays in cellular biology, both in normal physiology and in disease, new materials and methods are continually being developed to probe the activity of electrically excitable cells such as neurons and muscle cells.

Effects of Nanoparticle Properties on Kartogenin Delivery and Interactions with Mesenchymal Stem Cells.

Clinical trials with mesenchymal stem cells (MSCs) have demonstrated potential to treat osteoarthritis, a debilitating disease that affects millions. However, these therapies are often less effective due to heterogeneous MSC differentiation. Kartogenin (KGN), a synthetic small molecule that induces chondrogenesis, has recently been explored to decrease this heterogeneity.

Degradation of alkanethiol self-assembled monolayers in mesenchymal stem cell culture.

Alkanethiol self-assembled monolayers (SAMs) have been used extensively in studying the role of surface functionality and geometry on stem cell differentiation; however, the effects of stem cell culture conditions on SAM stability over time are not well understood. In this work, we examined the physical and chemical changes occurring on gold (Au)-SAM surfaces over time as a function of Au thickness. Within a narrow range of thicknesses (4, 8, and 10 nm), we observed significant differences in temporal SAM stability for a commonly utilized, hydrophilic, protein and cell repulsive oligo(ethylene) glycol alkanethiol (HS-(CH ) (O(CH ) ) OH) SAM and the hydrophobic, protein adhesive hexadecanethiol (SH-(CH ) CH ) SAM.

Advances in cellular and tissue engineering using layer-by-layer assembly.

Layer-by-layer (LbL) assembly is a self-assembly technique used to develop multilayer films based on complementary interactions between film components. These multilayer films have had a significant impact on the fields of cellular and tissue engineering. The aim of cellular engineering is to understand and control cell behavior, which not only impacts applications in regenerative medicine but also other biomedical therapies that rely on cell interactions with biomaterials, including treatments for autoimmune disorders and cancer.