A high-precision wound healing assay based on photosensitized culture substrates.

Quantitative assessment of cell migration in vitro is often required in fundamental and applied research from different biomedical areas including wound repair, tumor metastasis or developmental biology. A collection of assays has been established throughout the years like the most widely used scratch assay or the so-called barrier assay. It is the principle of these assays to introduce a lesion into an otherwise confluent monolayer in order to study the migration of cells from the periphery into this artificial wound and determine the migration rate from the time necessary for wound closure. A novel assay makes use of photosensitizers doped into a polystyrene matrix. A thin layer of this composite material is coated on the bottom of regular cell culture ware showing perfect biocompatibility. When adherent cells are grown on this coating, resonant excitation of the photosensitizer induces a very local generation of 1O2, which kills the cells residing at the site of illumination. Cells outside the site of illumination are not harmed. When excitation of the photosensitizer is conducted by microscopic illumination, high-precision wounding in any size and geometry is available even in microfluidic channels. Besides proof-of-concept experiments, this study gives further insight into the mechanism of photosensitizer-mediated cell wounding.

The Role of Community Health Agents in Promoting Social Change in Peru.

BACKGROUND: Community health agents (CHAs) provide basic health services and increase health care access thereby improving health outcomes for peri-urban regions in Peru. Few studies analyze the effect that becoming a CHA has on women's interpersonal interactions. We aim to explore the impact CHAs may have on gender and social norms through their roles as trusted leaders in male-dominated communities. METHODS: We conducted six 90-minute group discussions with CHAs working in Huancayo and Trujillo, Peru. We designed the discussions to extract data about family and community norms that changed as a result of working as a CHA. RESULTS: A total of 53 female CHAs participated in six discussion groups. CHAs reported shifting family support (a change in how their family supported them in their role as a CHA), gaining status within their family (feeling more valued for their knowledge and experience), and shifting family gender roles (men and boys taking on more household responsibilities) as a result of their work. CHAs also reported a change in community norms and felt they were more valued and respected within their communities as women leaders. CONCLUSIONS: Working as a CHA creates an opportunity to enact social change through altering family dynamics and community perceptions. Moreover, empowering women to become CHAs not only generates tangible benefits in community health, but can help create social change that ultimately improves the lives of women and realize their human rights.

Monitoring the Reversibility of GPCR Signaling by Combining Photochromic Ligands with Label-free Impedance Analysis.

G protein-coupled cell surface receptors (GPCR) trigger complex intracellular signaling cascades upon agonist binding. Classic pharmacological assays provide information about binding affinities, activation or blockade at different stages of the signaling cascade, but real time dynamics and reversibility of these processes remain often disguised. We show that combining photochromic NPY receptor ligands, which can be toggled in their receptor activation ability by irradiation with light of different wavelengths, with whole cell label-free impedance assays allows observing the cell response to receptor activation and its reversibility over time. The concept demonstrated on NPY receptors may be well applicable to many other GPCRs providing a deeper insight into the time course of intracellular signaling processes.

Community Health Agents Advancing Women's Empowerment: A Qualitative Data Analysis.

Community health agents (CHAs) play a critical role in primary healthcare delivery and health promotion in low-resource settings. Though there is substantial evidence of the benefits of CHAs in achieving targeted community health outcomes, there is limited research into the impact of empowerment experienced by CHAs themselves. This study examined how working as a CHA impacts the lives and self-perceptions of women in Peru volunteering with Catholic Medical Mission Board's (CMMB) markedly successful robust CHA model. We conducted six focus group discussions (FGDs) of 53 CHAs who implement CMMB programming in Trujillo and Huancayo, Peru. The FGDs were designed to explore themes related to empowerment, changes in women's lives, and perceptions of themselves. We identified four major themes related to women's empowerment: achievements, agency, meaningfulness, and resources. The most common empowerment theme was achievements, expressed through subthemes of changes in family behavior, self worth, education, health and nutrition, and rights and politics. The second most common empowerment theme was agency, with subthemes related to increases in using their voice, confidence, decision making, and participation. CHAs also reported experiencing empowerment through enhanced meaningfulness. CMMB's CHA model is an example of how well-structured community programs can facilitate women's empowerment. Providing meaningful community leadership opportunities can have far-reaching effects on women's perceptions of themselves as valuable, capable, and empowered leaders. This work deepens our understanding of how to practically improve community health through empowering women to catalyze gender equality in communities with disproportionate barriers and limited opportunities burdening them.

Label-free impedance measurements to unravel biomolecular interactions involved in G protein-coupled receptor signaling.

G protein-coupled receptors (GPCRs) are among the most heavily addressed drug targets in medicinal chemistry and pharmacology. The screening for new agonists or antagonists has been largely based on genetically engineered cells overexpressing the receptor to study binding of ligands directly or via intracellular signaling events downstream of receptor activation. These approaches are often invasive in nature, need to be conducted as endpoint assays, require isotope- or fluorophore-labeling and significant genetic manipulation. In contrast to that, non-invasive and label-free impedance measurements are capable of monitoring ligand-receptor interactions in target cells with endogenous receptor expression in real time. The cells expressing the receptor are grown on planar gold-film electrodes that are integrated into regular cell culture dishes. This article will highlight several impedance-based assay formats to characterize biomolecular interactions between ligands and their GPCRs in vitro, comprising agonist and antagonist characterization, dose-response relationships, receptor desensitization, and signal transduction profiling.

Stepwise Dosing Protocol for Increased Throughput in Label-Free Impedance-Based GPCR Assays.

Label-free impedance-based assays are increasingly used to non-invasively study ligand-induced GPCR activation in cell culture experiments. The approach provides real-time cell monitoring with a device-dependent time resolution down to several tens of milliseconds and it is highly automated. However, when sample numbers get high (e.g., dose-response studies for various different ligands), the cost for the disposable electrode arrays as well as the available time resolution for sequential well-by-well recordings may become limiting. Therefore, we here present a serial agonist addition protocol which has the potential to significantly increase the output of label-free GPCR assays. Using the serial agonist addition protocol, a GPCR agonist is added sequentially in increasing concentrations to a single cell layer while continuously monitoring the sample's impedance (agonist mode). With this serial approach, it is now possible to establish a full dose-response curve for a GPCR agonist from just one single cell layer. The serial agonist addition protocol is applicable to different GPCR coupling types, Gq Gi/0 or Gs and it is compatible with recombinant and endogenous expression levels of the receptor under study. Receptor blocking by GPCR antagonists is assessable as well (antagonist mode).