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Specific interactions between viruses and host cells provide essential insights into material science-based strategies to combat emerging viral diseases. pH-triggered viral fusion is ubiquitous to multiple viral families and is important for understanding the viral infection cycle. Inspired by this process, virus detection has been achieved using nanomaterials with host-mimetic membranes, enabling interactions with amphiphilic hemagglutinin fusion peptides of viruses. Most research has been on designing functional nanoparticles with fusogenic capability for virus detection, and there has been little exploitation of the kinetic stability to alter the ability of nanoparticles to interact with viral membranes and improve their sensing performance. In this study, a homogeneous fluorescent assay using self-assembled polymeric nanoparticles (PNPs) with tunable responsiveness to external stimuli is developed for rapid and straightforward detection of an activated influenza A virus. Dissociation of PNPs induced by virus insertion can be readily controlled by varying the fraction of hydrophilic segments in copolymers constituting PNPs, giving rise to fluorescence signals within 30 min and detection of various influenza viruses, including H9N2, CA04(H1N1), H4N6, and H6N8. Therefore, the designs demonstrated in this study propose underlying approaches for utilizing engineered PNPs through modulation of their kinetic stability for direct and sensitive identification of infectious viruses.

The use of drug-eluting stents (DESs) is a promising strategy for non-vascular diseases, especially human biliary cancer. However, the implementation of DESs suffers from two major obstacles: the side effects of drugs and the difficulty of controlling the drug release. These problems can be overcome if the stent elutes targeting nanoparticles that release drugs at time intervals that are dictated by the mechanisms of those drugs. We designed temporally controlled polymeric multi-prodrug nanoparticles (TCMPNs) that can be eluted from stents comprising polyurethane (PU) nanofiber as a polymeric matrix and paclitaxel (PTX)-loaded, CD44-targeting, hyaluronic acid-conjugated poly(lactic-co-glycolic acid) and gemcitabine (GEM) (P-H-G). TCMPNs enable two different types of drugs to be released temporally; PTX is released first owing to the collapse of the structure in the endosomes, and GEM, which induces synergistic anticancer activities, is hydrolyzed from P-H-G later in response to low pH. Embedded in the PU nanofiber, the TCMPNs demonstrate low initial burst behavior and sustainable release of the prodrug in vitro. Furthermore, TCMPN-eluting stents (TESs) exhibit continuous synergistic efficacy as available targeted cellular uptake prodrug delivery systems in tumor-bearing mice. These results demonstrate that this technology will open up cancer therapy by combining localized delivery and functional multi-drug-loaded nanoparticles.

The integration of contrast-enhanced diagnostic imaging and therapy could utilize image guided therapy to plan treatment strategy. Toward this goal, a unique construction and operation of a pseudo metal based photothermal therapeutic agent (PPAM) is introduced by polyaniline (PANI) generation templated on iron oxide metal nanoclusters (MNCs). Notably, MNC core interferes as a catalytic agent and enables aniline polymerization under ambient acidic conditions. The intrusion of transition metal enhanced the proton sensitivity of PANI, which led to pH responsive conversion even at dilute proton concentrations (pH 5, 6) compared to the PANI particles prepared by conventional methods. Under physiological pH, PPAM reveals no special features; however, under low pH conditions, which is a notable characteristic of the cancer microenvironment, PPAM automatically converts into its emeraldine salt (ES) state and thus activates as a photothermal therapeutic agent. Utilizing this specific redox responsive switched off-on behavior of PPAM, precise and systemized photothermal therapy is demonstrated, proving itself as a smart and efficient photothermal therapeutic agent.

Correction for ‘Stent containing CD44-targeting polymeric prodrug nanoparticles that release paclitaxel and gemcitabine in a time interval-controlled manner for synergistic human biliary cancer therapy’ by Dayeon Yun et al., J. Mater. Chem. B, 2017, 5, 6317–6324.

Molecular targeted delivery of therapeutic agents and their stimuli-responsive release are some of the major issues for modern medical administration, particularly in cancer chemotherapy. In this study, we developed a π-hyaluronan nanocarrier (πHNC) for CD44-targeted and pH-boosted delivery of an aromatic anticancer drug to cancer cells. Amphiphilic π-hyaluronan (pyrenyl hyaluronan, πHA) was synthesized using EDC chemistry, and self-assembled to form πHNC, the structure of which was obviously micellar but was convincingly effective to function; (i) a π-rich pyrenyl core of πHNC, a loading aromatic drug (doxorubicin, DOX) by π-stacking attraction, showed a rapid release profile under low pH conditions which is a notable characteristic of the cancer microenvironment as well as the endolysosomal state after uptake into the target cell and (ii) the hydrophilic hyaluronan shell of πHNC acted as a ligand for CD44 resulting in the localization of πHNC into the target cell by CD44-mediated endocytosis, without cytotoxicity. With its targeted and stimulated delivery of aromatic drugs to the target cells, DOX-loaded πHNC (πHNC/DOX) provided effectual therapeutic activity in both in vitro and in vivo models of CD44-positive human gastric cancer, which is suitable as a facile and efficient drug delivery platform.