Existing techniques to encapsulate cells into microscale hydrogels generally yield high polymer-to-cell ratios and lack control over the hydrogel’s mechanical properties1. Here, we report a microfluidic-based method for encapsulating single cells in a ~6 micron layer of alginate that increases the proportion of cell-containing microgels by 10-fold, with encapsulation efficiencies over 90%. We show that in vitro cell viability was maintained over a three-day period, that the microgels are mechanically tractable, and that for microscale cell assemblages of encapsulated marrow stromal cells cultured in microwells, osteogenic differentiation of encapsulated cells depends on gel stiffness and cell density. We also show that intravenous injection of singly-encapsulated marrow stromal cells into mice delays clearance kinetics and sustains donor-derived soluble factors in vivo. The encapsulation of single cells in tunable hydrogels should find use in a variety of tissue engineering and regenerative medicine applications.

BackgroundAs the increasing prevalence of type 2 diabetes mellitus has put pressure on health systems to appropriately manage these patients, there have been a growing number of mobile apps designed to improve the self-management of diabetes. One such app, BlueStar, has been shown to significantly reduce hemoglobin A1c (HbA1c) levels in small studies and is the first app in the United States to receive Food and Drug Administration approval as a mobile prescription therapy. However, the impact of the app across real-world population among different clinical sites and health systems remains unclear.ObjectiveThe primary objective of this study was to conduct a pragmatic randomized controlled trial of the BlueStar mobile app to determine if app usage leads to improved HbA1c levels among diverse participants in real-life clinical contexts. We hypothesized that this mobile app would improve self-management and HbA1c levels compared with controls.MethodsThe study consisted of a multicenter pragmatic randomized controlled trial. Overall, 110 participants randomized to the immediate treatment group (ITG) received the intervention for 6 months, and 113 participants randomized to the wait-list control (WLC) group received usual care for the first 3 months and then received the intervention for 3 months. The primary outcome was glucose control measured by HbA1c levels at 3 months. Secondary outcomes assessed intervention impact on patient self-management, experience of care, and self-reported health utilization using validated scales, including the Problem Areas in Diabetes, the Summary of Diabetes Self-Care Activities, and the EuroQol-5D. Intervention usage data were collected directly from the app.ResultsThe results of an analysis of covariance controlling for baseline HbA1c levels did not show evidence of intervention impact on HbA1c levels at 3 months (mean difference [ITG−WLC] −0.42, 95% CI −1.05 to 0.21; P=.19). Similarly, there was no intervention effect on secondary outcomes measuring diabetes self-efficacy, quality of life, and health care utilization behaviors. An exploratory analysis of 57 ITG participants investigating the impact of app usage on HbA1c levels showed that each additional day of app use corresponded with a 0.016-point decrease in participants’ 3-month HbA1c levels (95% CI −0.03 to −0.003). App usage varied significantly by site, as participants from 1 site logged in to the app a median of 36 days over 14 weeks (interquartile range [IQR] 10.5-124); those at another site used the app significantly less (median 9; IQR 6-51).ConclusionsThe results showed no difference between intervention and control arms for the primary clinical outcome of glycemic control measured by HbA1c levels. Although there was low usage of the app among participants, results indicate contextual factors, particularly site, had a significant impact on overall usage. Future research into the patient and site-specific factors that increase app utilization are needed.Trial RegistrationClinicaltrials.gov NCT02813343; https://clinicaltr...

No abstract

Mesenchymal stromal cells (MSCs) modulate immune cells to ameliorate multiple inflammatory pathologies. Biophysical signals that regulate this process are poorly defined. By engineering hydrogels with tunable biophysical parameters relevant to bone marrow where MSCs naturally reside, we show that soft extracellular matrix maximizes the ability of MSCs to produce paracrine factors that have been implicated in monocyte production and chemotaxis upon inflammatory stimulation by tumor necrosis factor–α (TNFα). Soft matrix increases clustering of TNF receptors, thereby enhancing NF-κB activation and downstream gene expression. Actin polymerization and lipid rafts, but not myosin-II contractility, regulate mechanosensitive activation of MSCs by TNFα. We functionally demonstrate that human MSCs primed with TNFα in soft matrix enhance production of human monocytes in marrow of xenografted mice and increase trafficking of monocytes via CCL2. The results suggest the importance of biophysical signaling in tuning inflammatory activation of stromal cells to control the innate immune system.

Community health workers can be a highly effective, low-cost strategy for increasing influenza vaccination among college students. This model could also be used to address other campus health challenges where student engagement is key.