Bacterial pneumonia is one of the leading causes of death worldwide and exerts a significant burden on health-care resources. Antibiotics have long been used as first-line drugs for the treatment of bacterial pneumonia. However, antibiotic therapy and traditional antibiotic delivery are associated with important challenges, including drug resistance, low bioavailability, and adverse side effects; the existence of physiological barriers further hampers treatment. Fortunately, these limitations may be overcome by the application of nanotechnology, which can facilitate drug delivery while improving drug stability and bioavailability. This review summarizes the challenges facing the treatment of bacterial pneumonia and also highlights the types of nanoparticles that can be used for antibiotic delivery. This review places a special focus on the state-of-the-art in nanomaterial-based approaches to the delivery of antibiotics for the treatment of pneumonia.

Magnetic resonance (MR) angiography is one of the main diagnostic approaches for cardiac-cerebral vascular diseases. Nevertheless, the non-contrast-enhanced MR angiography suffers from its intrinsic problems derived from the blood flow-dependency, while the clinical Gd-chelating contrast agents are limited by their rapid vascular extravasation. Herein, we report a hypersensitive MR angiography strategy based on interlocking stratagem of zwitterionic Gd-chelate contrast agents (PAA-Gd). The longitudinal molar relaxivity of PAA-Gd was 4.6-times higher than that of individual Gd-chelates as well as appropriate blood half-life (73.8 min) and low immunogenicity, enabling sophisticated micro-vessels angiography with a resolution at the order of hundred micrometers. A series of animal models of cardiac-cerebrovascular diseases have been built for imaging studies on a 7.0 T MRI scanner, while the clinical translation potential of PAA-Gd has been evaluated on swine on a 3.0 T clinical MRI scanner. The current studies offer a promising strategy for precise diagnosis of vascular diseases.

Chemodynamic therapy as a novel type of chemotherapy can damage the DNA structures and induce cell apoptosis and immunogenic cell death (ICD) through generating reactive oxygen species (ROS) to aggravate oxidative stress. Nonetheless, as an intrinsic antioxidative response of tumor cells, the expression of glutathione (GSH) can be upregulated to maintain the cellular redox balance and protect the tumor cells from ROS-mediated damage. In this context, it is feasible to simultaneously boost ROS generation and GSH depletion in tumor cells; however, the precise delivery and release of GSH scavengers at specific subcellular sites is of great importance. Herein, we propose a GSH-responsive mesoporous organosilica nanoparticle (MON)-based nanomedicine MON-CA-TPP@HA through sequentially covalently attaching triphenylphosphine (TPP) and electrostatically coating hyaluronic acid (HA) onto the surface of cinnamaldehyde (CA)-loaded MONs, known as MON-CA-TPP@HA, which has been demonstrated to be an extremely effective therapeutic strategy for cancer treatment through inducing ICD and apoptosis of breast cancer cells. Systematic in vitro experimental results clearly revealed that the nanomedicine can actively target the tumor cells with the help of HA, subsequently enter the tumor cells, and precisely bind with the mitochondria through TPP residues. Upon cleavaging the disulfide bond in the MONs triggered by over-expressed GSH within tumors, the CA molecules can be released inducing the excessive ROS in situ surrounding the mitochondria to activate oxidative stress to induce apoptosis and ICD of breast cancer cells. The results of the in vivo experiments confirm that the MON-CA-TPP@HA nanomedicine can effectively promote dendritic cell (DC) maturation and CD 8⁺ T cell activation and regulate the ratio of M1/M2 macrophages, which improve tumor immunosuppressive microenvironment. It is thus believed that the current nanomedicine has paved a new way for future cancer therapy.

The effect of surface charge on the tumor-targeting in vivo is different from that at cell level. The neutral nanoparticles exhibit stronger tumor uptake, while the charged ones accelerate the RES/MPS uptake, making their active-targeting useless.

Malignant tumors have become one of the major causes of human death, but there remains a lack of effective methods for tiny tumor diagnosis, metastasis warning, clinical efficacy prediction, and effective treatment. In this context, localizing tiny tumors via imaging and non-invasively extracting molecular information related to tumor proliferation, invasion, metastasis, and drug resistance from the tumor microenvironment have become the most fundamental tasks faced by cancer researchers. Tumor-associated microenvironmental physiological parameters, such as hypoxia, acidic extracellular pH, protease, reducing conditions, and so forth, have much to do with prognostic indicators for cancer progression, and impact therapeutic administrations. By combining with various novel nanoparticle-based activatable probes, molecular imaging technologies can provide a feasible approach to visualize tumor-associated microenvironment parameters noninvasively and realize accurate treatment of tumors. This review focuses on the recent achievements in the design of “smart” nanomedicine responding to the tumor microenvironment-related features and highlights state-of- the-art technology in tumor imaging diagnosis and therapy.

Determining therapeutic efficacy is critical for tumor precision theranostics. In order to monitor the efficacy of anti-cancer drugs (e.g., Paclitaxel), a pH-sensitive ratiometric fluorescent imaging probe was constructed. The pH-sensitive ratiometric fluorescent dye ANNA was covalently coupled to the N-terminal of the cell-penetrating TAT peptide through an amidation reaction (TAT-ANNA). The in vitro cellular experiments determined that the TAT-ANNA probe could penetrate the cell membrane and image the intracellular pH in real time. The in vivo experiments were then carried out, and the ratiometric pH response to the state of the tumor was recorded immediately after medication. The TAT-ANNA probe was successfully used to monitor the pharmacodynamics of anti-cancer drugs in vivo.