Gold nanostructure-integrated conductive microwell arrays for uniform cancer spheroid formation and electrochemical drug screening.

Cancer spheroids, which mimic distinct cell-to-cell and cell-extracellular matrix interactions of solid tumors in vitro, have emerged as a promising tumor model for drug screening. However, owing to the unique characteristics of spheroids composed of three-dimensionally densely-packed cells, the precise characterizations of cell viability and function with conventional colorimetric assays are challenging. Herein, we report gold nanostructure-integrated conductive microwell arrays (GONIMA) that enable both highly efficient uniform cancer spheroid formation and precise electrochemical detection of cell viability. A nanostructured gold on indium tin oxide (ITO) substrate facilitated the initial cell aggregation and further 3D cell growth, while the non-cytophilic polymer microwell arrays restricted the size and shape of the spheroids. As a result, approximately 150 human glioblastoma spheroids were formed on a chip area of 1.13 cm2 with an average diameter of 224 µm and a size variation of only 5% (±11.36 µm). The high uniformity of cancer spheroids contributed to the stability of electrical signals measuring cell viability. Using the fabricated GONIMA, the effects of a representative chemotherapeutic agent, hydroxyurea, on the glioblastoma spheroids were precisely monitored under conditions of varying drug concentrations (0-0.3 mg/mL) and incubation times (24-48 h). Therefore, we conclude that the newly developed platform is highly useful for rapid and precise in vitro drug screening, as well as for the pharmacokinetic analyses of specific drugs using 3D cellular cancer models.

Image-guided in situ cancer vaccination with combination of multi-functional nano-adjuvant and an irreversible electroporation technique.

Cancer immunotherapy is a next-generation treatment strategy; however, its side effects limit its clinical translation. Here, a novel combination of a multi-functional nano-adjuvant (M-NA) prepared with an iron oxide/gold core and a cationic polymer shell via multilayer synthesis with CpG oligodeoxynucleotide (CpG-ODN) electrostatically complexed on its surface, and irreversible electroporation (IRE) technique was developed for effective image-guided in situ cancer vaccination. The M-NA can be retained long-term in the dense tumoral extracellular matrix after intratumoral injection and internalized by antigen-presenting cells (APCs). The IRE can induce immunogenic cell death. Indeed, in a mouse tumor model, the M-NA showed longer tumor retention time than free CpG-ODN. Compared with other treatments, the combined treatment significantly inhibited tumor growth with 100% survival rate for ∼60 days. The therapy induced the activation of cytotoxic lymphocytes and the maturation of APCs in vivo. This treatment could be effective in image-guided local cancer immunotherapy.

Long-acting nanoparticulate DNase-1 for effective suppression of SARS-CoV-2-mediated neutrophil activities and cytokine storm.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new strain of coronavirus not previously identified in humans. Globally, the number of confirmed cases and mortality rates of coronavirus disease 2019 (COVID-19) have risen dramatically. Currently, there are no FDA-approved antiviral drugs and there is an urgency to develop treatment strategies that can effectively suppress SARS-CoV-2-mediated cytokine storms, acute respiratory distress syndrome (ARDS), and sepsis. As symptoms progress in patients with SARS-CoV-2 sepsis, elevated amounts of cell-free DNA (cfDNA) are produced, which in turn induce multiple organ failure in these patients. Furthermore, plasma levels of DNase-1 are markedly reduced in SARS-CoV-2 sepsis patients. In this study, we generated recombinant DNase-1-coated polydopamine-poly(ethylene glycol) nanoparticulates (named long-acting DNase-1), and hypothesized that exogenous administration of long-acting DNase-1 may suppress SARS-CoV-2-mediated neutrophil activities and the cytokine storm. Our findings suggest that exogenously administered long-acting nanoparticulate DNase-1 can effectively reduce cfDNA levels and neutrophil activities and may be used as a potential therapeutic intervention for life-threatening SARS-CoV-2-mediated illnesses.