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Cameras are everywhere, and are increasingly coupled with video analytics software that can identify our face, track our mood, recognize what we are doing, and more. We present the results of a 10-day in-situ study designed to understand how people feel about these capabilities, looking both at the extent to which they expect to encounter them as part of their everyday activities and at how comfortable they are with the presence of such technologies across a range of realistic scenarios. Results indicate that while some widespread deployments are expected by many (e.g., surveillance in public spaces), others are not, with some making people feel particularly uncomfortable. Our results further show that individuals’ privacy preferences and expectations are complicated and vary with a number of factors such as the purpose for which footage is captured and analyzed, the particular venue where it is captured, and whom it is shared with. Finally, we discuss the implications of people’s rich and diverse preferences on opt-in or opt-out rights for the collection and use (including sharing) of data associated with these video analytics scenarios as mandated by regulations. Because of the user burden associated with the large number of privacy decisions people could be faced with, we discuss how new types of privacy assistants could possibly be configured to help people manage these decisions. 

Mechanical cues from the extracellular matrix (ECM) regulate vascular endothelial cell (EC) morphology and function. Since naturally derived ECMs are viscoelastic, cells respond to viscoelastic matrices that exhibit stress relaxation, in which a cell‐applied force results in matrix remodeling. To decouple the effects of stress relaxation rate from substrate stiffness on EC behavior, we engineered elastin‐like protein (ELP) hydrogels in which dynamic covalent chemistry (DCC) was used to crosslink hydrazine‐modified ELP (ELP‐HYD) and aldehyde/benzaldehyde‐modified polyethylene glycol (PEG‐ALD/PEG‐BZA). The reversible DCC crosslinks in ELP‐PEG hydrogels create a matrix with independently tunable stiffness and stress relaxation rate. By formulating fast‐relaxing or slow‐relaxing hydrogels with a range of stiffness (500–3300 Pa), we examined the effect of these mechanical properties on EC spreading, proliferation, vascular sprouting, and vascularization. The results show that both stress relaxation rate and stiffness modulate endothelial spreading on two‐dimensional substrates, on which ECs exhibited greater cell spreading on fast‐relaxing hydrogels up through 3 days, compared with slow‐relaxing hydrogels at the same stiffness. In three‐dimensional hydrogels encapsulating ECs and fibroblasts in coculture, the fast‐relaxing, low‐stiffness hydrogels produced the widest vascular sprouts, a measure of vessel maturity. This finding was validated in a murine subcutaneous implantation model, in which the fast‐relaxing, low‐stiffness hydrogel produced significantly more vascularization compared with the slow‐relaxing, low‐stiffness hydrogel. Together, these results suggest that both stress relaxation rate and stiffness modulate endothelial behavior, and that the fast‐relaxing, low‐stiffness hydrogels supported the highest capillary density in vivo.

 

Neural progenitor cells (NPCs) are promising therapeutic candidates for nervous system regeneration. Significant efforts focus on developing hydrogel‐based approaches to facilitate the clinical translation of NPCs, from scalable platforms for stem cell production to injectable carriers for cell transplantation. However, fundamental questions surrounding NPC‐hydrogel interactions remain unanswered. While matrix degradability is known to regulate the stemness and differentiation capacity of NPCs, how degradability impacts NPC epigenetic regulation and secretory phenotype remains unknown. To address this question, NPCs encapsulated in recombinant protein hydrogels with tunable degradability are assayed for changes in chromatin organization and neurotrophin expression. In high degradability gels, NPCs maintain expression of stem cell factors, proliferate, and have large nuclei with elevated levels of the stemness‐associated activating histone mark H3K4me3. In contrast, NPCs in low degradability gels exhibit more compact, rounded nuclei with peripherally localized heterochromatin, are non‐proliferative yet non‐senescent, and maintain expression of neurotrophic factors with potential therapeutic relevance. This work suggests that tuning matrix degradability may be useful to direct NPCs toward either a more‐proliferative, stem‐like phenotype for cell replacement therapies, or a more quiescent‐like, pro‐secretory phenotype for soluble factor‐mediated therapies.

 

Neural progenitor cells (NPCs) are a promising cell source to repair damaged nervous tissue. However, expansion of therapeutically relevant numbers of NPCs and their efficient differentiation into desired mature cell types remains a challenge. Material‐based strategies, including culture within 3D hydrogels, have the potential to overcome these current limitations. An ideal material would enable both NPC expansion and subsequent differentiation within a single platform. It has recently been demonstrated that cell‐mediated remodeling of 3D hydrogels is necessary to maintain the stem cell phenotype of NPCs during expansion, but the role of matrix remodeling on NPC differentiation and maturation remains unknown. By culturing NPCs within engineered protein hydrogels susceptible to degradation by NPC‐secreted proteases, it is identified that a critical amount of remodeling is necessary to enable NPC differentiation, even in highly degradable gels. Chemical induction of differentiation after sufficient remodeling time results in differentiation into astrocytes and neurotransmitter‐responsive neurons. Matrix remodeling modulates expression of the transcriptional co‐activator Yes‐associated protein, which drives expression of NPC stemness factors and maintains NPC differentiation capacity, in a cadherin‐dependent manner. Thus, cell‐remodelable hydrogels are an attractive platform to enable expansion of NPCs followed by differentiation of the cells into mature phenotypes for therapeutic use.

 

Human intestinal organoids from primary human tissues have the potential to revolutionize personalized medicine and preclinical gastrointestinal disease models. A tunable, fully defined, designer matrix, termed hyaluronan elastin‐like protein (HELP) is reported, which enables the formation, differentiation, and passaging of adult primary tissue‐derived, epithelial‐only intestinal organoids. HELP enables the encapsulation of dissociated patient‐derived cells, which then undergo proliferation and formation of enteroids, spherical structures with polarized internal lumens. After 12 rounds of passaging, enteroid growth in HELP materials is found to be statistically similar to that in animal‐derived matrices. HELP materials also support the differentiation of human enteroids into mature intestinal cell subtypes. HELP matrices allow stiffness, stress relaxation rate, and integrin‐ligand concentration to be independently and quantitatively specified, enabling fundamental studies of organoid–matrix interactions and potential patient‐specific optimization. Organoid formation in HELP materials is most robust in gels with stiffer moduli (G’≈ 1 kPa), slower stress relaxation rate (t_1/2≈ 18 h), and higher integrin ligand concentration (0.5 × 10⁻³–1 × 10⁻³mRGD peptide). This material provides a promising in vitro model for further understanding intestinal development and disease in humans and a reproducible, biodegradable, minimal matrix with no animal‐derived products or synthetic polyethylene glycol for potential clinical translation.