Search

Mimics of adnexal masses can include uterine leiomyomas, intraperitoneal cystic and solid masses of mesenteric or gastrointestinal origin, and extraperitoneal cystic and solid masses. When a pelvic mass is discovered on imaging, a radiologist should recognize these mimics to avoid mischaracterization of a mass as ovarian for optimal patient management. Knowledge of pelvic anatomy, determining whether a mass is intraperitoneal or extraperitoneal, and troubleshooting with MR imaging can help determine the etiology and origin of a pelvic mass. Imaging characteristics and keys to diagnosis of these adnexal mass mimics are reviewed in this article.

Self-assembled polymer nanostructures are useful for many applications, including biomedicine, energy, and sensing, often presenting a more stable and customizable alternative for drug delivery than lipid-based assemblies, like liposomes. Polyethylene glycol-b-poly(propylene sulfide) (PEG-b-PPS) nanostructures are an example of a cutting-edge self-assembled polymer system. Here, to better understand the impact of electron irradiation on the molecular and macroscale structure, we utilize analytical scanning transmission electron microscopy. Through electron energy-loss spectroscopy (EELS), we access information regarding the degradation of PEG-b-PPS self-assembled polymers under the electron beam. By coupling the spatial and temporal resolution afforded by EELS, we describe the movement of elements in the polymer system during radiolysis and propose a mechanism for sample degradation. We believe this work will serve as a blueprint to determine the effects of electron irradiation on polymer architectures via spectroscopy.

Magnetic nanostructures (MNS) have a wide range of biological applications due to their biocompatibility, superparamagnetic properties, and customizable composition that includes iron oxide (Fe3O4), Zn2+, and Mn2+. However, several challenges to the biomedical usage of MNS must still be addressed, such as formulation stability, inability to encapsulate therapeutic payloads, and variable clearance rates in vivo. Here, we enhance the utility of MNS during controlled delivery applications via encapsulation within polymeric bicontinuous nanospheres (BCNs) composed of poly(ethylene glycol)-block-poly(propylene sulfide) (PEG-b-PPS) copolymers. PEG-b-PPS BCNs have demonstrated versatile encapsulation and delivery capabilities for both hydrophilic and hydrophobic payloads due to their unique and highly organized cubic phase nanoarchitecture. MNS-embedded BCNs (MBCNs) were thus coloaded with physicochemically diverse molecular payloads using the technique of flash nanoprecipitation and characterized in terms of their structure and in vivo biodistribution following intravenous administration. Retention of the internal aqueous channels and cubic architecture of MBCNs were verified using cryogenic transmission electron microscopy and small-angle X-ray scattering, respectively. MBCNs demonstrated improvement in magnetic resonance imaging (MRI) contrast enhancement (r2 relaxivity) as compared to free MNS, which in combination with scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy evidenced the clustering and continued access to water of MNS following encapsulation. Furthermore, MBCNs were found to be noncytotoxic and able to deliver their hydrophilic and hydrophobic small-molecule payloads both in vitro and in vivo. Finally, the oxidation sensitivity of the hydrophobic PPS block allowed MBCNs to undergo a unique, triggerable transition in morphology into MNS-bearing micellar nanocarriers. In summary, MBCNs are an attractive platform for the delivery of molecular and nanoscale payloads for diverse on-demand and sustained drug delivery applications.

Cardiovascular disease (CVD) is a leading cause of global mortality, accounting for pathologies that are primarily of atherosclerotic origin and driven by specific cell populations. A need exists for effective, non-invasive methods to assess the risk of potentially fatal major adverse cardiovascular events (MACE) before occurrence and to monitor post-interventional outcomes such as tissue regeneration. Molecular imaging has widespread applications in CVD diagnostic assessment, through modalities including magnetic resonance imaging (MRI), positron emission tomography (PET), and acoustic imaging methods. However, current gold-standard small molecule contrast agents are not cell-specific, relying on non-specific uptake to facilitate imaging of biologic processes. Nanomaterials can be engineered for targeted delivery to specific cell populations, and several nanomaterial systems have been developed for pre-clinical molecular imaging. Here, we review recent advances in nanoparticle-mediated approaches for imaging of cellular processes in cardiovascular disease, focusing on efforts to detect inflammation, assess lipid accumulation, and monitor tissue regeneration.

Bicontinuous nanospheres (BCNs) are polymeric analogs to lipid cubosomes, possessing cubic liquid crystalline phases with high internal surface area, aqueous channels for loading hydrophilic molecules, and high hydrophobic volume for lipophilic payloads. Primarily due to difficulties in scalable and consistent fabrication, neither controlled delivery of payloads via BCNs nor their organ or cellular biodistributions following in vivo administration have been demonstrated or characterized. We have recently validated flash nanoprecipitation as a rapid method of assembling uniform monodisperse 200-300 nm diameter BCNs from poly(ethylene glycol) -b-poly(propylene sulfide) (PEG -b-PPS) co-polymers. Here, we compare these BCNs both in vitro and in vivo to 100 nm PEG -b-PPS polymersomes (PSs), which have been well characterized as nanocarriers for controlled delivery applications. Using a small molecule fluorophore and a fluorescently tagged protein as respective lipophilic and water-soluble model cargos, we demonstrate that BCNs can achieve significantly higher encapsulation efficiencies for both payloads on a per unit mass basis. At time points of 4 and 24 h after intravenous administration to mice, we found significant differences in organ-level uptake between BCNs and PSs, with BCNs showing reduced accumulation in the liver and increased uptake in the spleen. Despite these organ-level differences, BCNs and PSs displayed strikingly similar uptake profiles by immune cell populations in vitro and in the liver, spleen, and blood, as assayed by flow cytometry. In conclusion, we have found PEG -b-PPS BCNs to be well suited for dual loading and delivery of molecular payloads, with a favorable organ biodistribution and high cell uptake by therapeutically relevant immune cell populations.

Many diseases that plague the modern medical world have their origins at the cellular or molecular level and, as such, require greater specificity to be effectively combated and cured. A number of recent advances in understanding the biology and biochemistry have enabled researchers to develop the specialized tools and techniques needed to detect and provide therapy for these debilitating conditions. Many of these treatments take advantage of the way that cells behave and interact with their environment or various properties of the cell’s structure and form. Researchers are able to surpass a number of cellular hurdles, such as the cell membrane, endosomal escape, and intracellular targeting to begin the arduous task of understanding, diagnosing, and treating diseases like cancer.