Single-cell Organelle Extraction with Cellular Indexing.

Bulk methods to fractionate organelles lack the resolution to capture single-cell heterogeneity. While microfluidic approaches attempt to fractionate organelles at the cellular level, they fail to map each organelle back to its cell of origin-crucial for multiomics applications. To address this, we developed VacTrap, a high-throughput microfluidic device for isolating and spatially indexing single nuclei from mammalian cells.

Spatial and Temporal Mapping of Articular Cartilage Poro-Viscoelastic Material Properties Using Indentation.

Biphasic poro-viscoelastic constitutive material model (BPVE) captures both the fluid flow dependent and independent behavior of cartilage under stress relaxation type indentation. A finite element model based on BPVE formulation was developed to explore the sensitivity of the model to Young's modulus, Poisson's ratio, permeability, and viscoelastic constitutive parameters expressed in terms of Prony series coefficients. Then we fit the numerical model to experimental force versus time curves from stress relaxation indents on bovine tibial plateaus to extract the material properties.

Best Practices for Germicidal Ultraviolet-C Dose Measurement for N95 Respirator Decontamination.

Ultraviolet-C (UV-C) decontamination holds promise in combating the coronavirus disease 2019 pandemic, particularly with its potential to mitigate the N95 respirator shortage. Safe, effective, and reproducible decontamination depends critically on UV-C dose, yet dose is frequently measured and reported incorrectly, which results in misleading and potentially harmful protocols. Understanding best practices in UV-C dose measurement for N95 respirator decontamination is essential to the safety of medical professionals, researchers, and the public.

Mapping of UV-C dose and SARS-CoV-2 viral inactivation across N95 respirators during decontamination.

During public health crises like the COVID-19 pandemic, ultraviolet-C (UV-C) decontamination of N95 respirators for emergency reuse has been implemented to mitigate shortages. Pathogen photoinactivation efficacy depends critically on UV-C dose, which is distance- and angle-dependent and thus varies substantially across N95 surfaces within a decontamination system. Due to nonuniform and system-dependent UV-C dose distributions, characterizing UV-C dose and resulting pathogen inactivation with sufficient spatial resolution on-N95 is key to designing and validating UV-C decontamination protocols.

Optical Attenuators Extend Dynamic Range but Alter Angular Response of Planar Ultraviolet-C Dosimeters.

Effective ultraviolet-C (UV-C) decontamination protocols of N95 respirators require validation that the entire N95 surface receives sufficient dose. Photochromic indicators (PCIs) can accurately measure UV-C dose on nonplanar surfaces, but often saturate below doses required to decontaminate porous, multilayered textiles like N95s. Here, we investigate the use of optical attenuators to extend PCI dynamic range while maintaining a near-ideal angular response-critical for accurate measurements of uncollimated UV-C.

Current Understanding of Ultraviolet-C Decontamination of N95 Filtering Facepiece Respirators.

The COVID-19 pandemic has led to critical shortages of single-use N95 filtering facepiece respirators. The US Centers for Disease Control and Prevention has identified ultraviolet-C (UV-C) irradiation as one of the most promising decontamination methods during crisis-capacity surges; however, understanding the mechanism of pathogen inactivation and post-treatment respirator performance is central to effective UV-C decontamination. We summarize the UV-C N95 decontamination evidence and identify key metrics.

Quantitative UV-C dose validation with photochromic indicators for informed N95 emergency decontamination.

With COVID-19 N95 shortages, frontline medical personnel are forced to reuse this disposable-but sophisticated-multilayer respirator. Widely used to decontaminate nonporous surfaces, UV-C light has demonstrated germicidal efficacy on porous, non-planar N95 respirators when all surfaces receive ≥1.0 J/cm2 dose.

UV-C decontamination for N95 emergency reuse: Quantitative dose validation with photochromic indicators.

With COVID-19 N95 respirator shortages, frontline medical personnel are forced to reuse this disposable - but sophisticated - multilayer textile respirator. Widely used for decontamination of nonporous surfaces, UV-C light has germicidal efficacy on porous, non-planar N95 respirators when ≥1.0 J/cm^2 dose is applied across all surfaces.

Laterally Aggregated Polyacrylamide Gels for Immunoprobed Isoelectric Focusing.

Immunoprobed isoelectric focusing (IEF) resolves proteins based on differences in isoelectric point (p) and then identifies protein targets through immunoprobing of IEF-separated proteins that have been immobilized onto a gel scaffold. During the IEF stage, the gel functions as an anti-convective medium and not as a molecular sieving matrix. During the immunoprobing stage, the gel acts as an immobilization scaffold for IEF-focused proteins via photoactive moieties.

Measurement of Thermodynamic Partitioning in Open Hydrogels.

Thermodynamic partitioning dictates solute loading and release from a hydrogel. Design of drug delivery vehicles, cell and tissue matrices, and immunoassay scaffolds that utilize hydrogel materials is informed by an understanding of the thermodynamic partitioning properties of those hydrogels. We develop aberration-compensated laser scanning confocal microscopy (AC-LSCM), a technique that can be applied to all fluorescence microscopy-based equilibrium partition coefficient measurements where the fluorescence is uniformly distributed in the reference material (e.

In vitro and in vivo evaluation of SU-8 biocompatibility.

SU-8 negative photoresist is a high tensile strength polymer that has been used for a number of biomedical applications that include cell encapsulation and neuronal probes. Chemically, SU-8 comprises, among other components, an epoxy based monomer and antimony salts, the latter being a potential source of cytotoxicity. We report on the in vitro and in vivo evaluation of SU-8 biocompatibility based on leachates from various solvents, at varying temperatures and pH, and upon subcutaneous implantation of SU-8 substrates in mice.

The transcription factor paired-related homeobox 1 (Prrx1) inhibits adipogenesis by activating transforming growth factor-β (TGFβ) signaling.

Differentiation of adipocytes from preadipocytes contributes to adipose tissue expansion in obesity. Impaired adipogenesis may underlie the development of metabolic diseases such as insulin resistance and type 2 diabetes. Mechanistically, a well defined transcriptional network coordinates adipocyte differentiation.