Analytical tools to assess polymer biodegradation: A critical review and recommendations.

Many petroleum-derived plastic materials are highly recalcitrant and persistent in the environment, posing significant threats to human and ecological receptors due to their accumulation in ecosystems. In recent years, research efforts have focused on advancing biological methods for polymer degradation. Enzymatic depolymerization has emerged as particularly relevant for biobased plastic recycling, potentially scalable for industrial use.

Natural diversity screening, assay development, and characterization of nylon-6 enzymatic depolymerization.

Successes in biocatalytic polyester recycling have raised the possibility of deconstructing alternative polymers enzymatically, with polyamide (PA) being a logical target due to the array of amide-cleaving enzymes present in nature. Here, we screen 40 potential natural and engineered nylon-hydrolyzing enzymes (nylonases), using mass spectrometry to quantify eight compounds resulting from enzymatic nylon-6 (PA6) hydrolysis. Comparative time-course reactions incubated at 40-70 °C showcase enzyme-dependent variations in product distributions and extent of PA6 film depolymerization, with significant nylon deconstruction activity appearing rare.

Descending thoracic aortic emergencies: Past, present, and future.

The most important descending thoracic aortic (DTA) pathologies are aneurysms, dissections, and traumatic injuries. In acute settings, these conditions can constitute a significant risk of bleeding or ischemia of vital organs, resulting in a fatal outcome. Morbidity and mortality associated with aortic pathologies remain significant, despite improvements in medical therapy and endovascular techniques.

Comparison of eosin and fluorescein conjugates for the photoinitiation of cell-compatible polymer coatings.

Targeted photopolymerization is the basis for multiple diagnostic and cell encapsulation technologies. While eosin is used in conjunction with tertiary amines as a water-soluble photoinitiation system, eosin is not widely sold as a conjugate with antibodies and other targeting biomolecules. Here we evaluate the utility of fluorescein-labeled bioconjugates to photopolymerize targeted coatings on live cells.

Hydrogel Patches on Live Cells through Surface-Mediated Polymerization.

Many naturally occurring cells possess an intrinsic ability to cross biological barriers that block conventional drug delivery, and these cells offer a possible mode of active transport across the blood-brain barrier or into the core of tumor masses. While many technologies for the formation of complete, nanoparticle-loaded coatings on cells exist, a complete coating on the cell surface would disrupt the interaction of cells with their environments. To address this issue, cell surface patches that partially cover cell surfaces might provide a superior approach for cell-mediated therapeutic delivery.

Ultrasound molecular imaging of ovarian cancer with CA-125 targeted nanobubble contrast agents.

Ultrasound is frequently utilized in diagnosis of gynecologic malignancies such as ovarian cancer. Because epithelial ovarian cancer (EOC) is often characterized by overexpression of cancer antigen 125 (CA-125), ultrasound contrast agents able to target this molecular signature could be a promising complementary strategy. In this work, we demonstrate application of CA-125-targeted echogenic lipid and surfactant-stabilized nanobubbles imaged with standard clinical contrast harmonic ultrasound for imaging of CA-125 positive OVCAR-3 tumors in mice.

The Role of Surface Receptor Density in Surface-Initiated Polymerizations for Cancer Cell Isolation.

Fluid biopsies potentially offer a minimally invasive alternative to traditional tissue biopsies for the continual monitoring of metastatic cancer. Current established technologies for isolating circulating tumor cells (CTCs) suffer from poor purity and yield and require fixatives that preclude the collection of viable cells for longitudinal analyses of biological function. Antigen specific lysis (ASL) is a rapid, high-purity method of cell isolation based on targeted protective coatings on antigen-presenting cells and lysis depletion of unprotected antigen-negative cells.

A Quantitative Perspective on Surface Marker Selection for the Isolation of Functional Tumor Cells.

Much effort has gone into developing fluid biopsies of patient peripheral blood for the monitoring of metastatic cancers. One common approach is to isolate and analyze tumor cells in the peripheral blood. Widespread clinical implementation of this approach has been hindered by the current choice of targeting epithelial markers known to be highly variable in primary tumor sites.

Protective Polymer Coatings for High-Throughput, High-Purity Cellular Isolation.

Cell-based therapies are emerging as the next frontier of medicine, offering a plausible path forward in the treatment of many devastating diseases. Critically, current methods for antigen positive cell sorting lack a high throughput method for delivering ultrahigh purity populations, prohibiting the application of some cell-based therapies to widespread diseases. Here we show the first use of targeted, protective polymer coatings on cells for the high speed enrichment of cells.

Characterization of molecular transport in ultrathin hydrogel coatings for cellular immunoprotection.

PEG hydrogels are routinely used in immunoprotection applications to hide foreign cells from a host immune system. Size-dependent transport is typically exploited in these systems to prevent access by macromolecular elements of the immune system while allowing the transport of low molecular weight nutrients. This work studies a nanoscale hydrogel coating for improved transport of beneficial low molecular weight materials across thicker hydrogel coatings while completely blocking transport of undesired larger molecular weight materials.

Interfacial polymerization for colorimetric labeling of protein expression in cells.

Determining the location of rare proteins in cells typically requires the use of on-sample amplification. Antibody based recognition and enzymatic amplification is used to produce large amounts of visible label at the site of protein expression, but these techniques suffer from the presence of nonspecific reactivity in the biological sample and from poor spatial control over the label. Polymerization based amplification is a recently developed alternative means of creating an on-sample amplification for fluorescence applications, while not suffering from endogenous labels or loss of signal localization.