Size and surface modification are the two key factors affecting the effect of macrophages polarization induced by superparamagnetic iron oxide nanoparticles (SPIONs). The smaller the particle size, the better the polarization effect of SPIONs. Besides, the reasonable SPIONs surface modification method can also be used to enhance the polarization effect. In this study, SPIONs was prepared by solvothermal method and optimized by Box-Benhnken center combination design and response surface method. Furthermore, astragalus polysaccharide-superparamagnetic iron oxide nanocomplex (APS-SPIONs) was successfully constructed by EDC/NHS esterification method. The structure of APS-SPIONs was confirmed by dynamic light scatter and infrared spectrometer, and the contents of iron and polysaccharide were characterized by spectrophotometry. The effect of APS-SPIONs on inducing mouse macrophages RAW264.7 polarization was investigated by flow cytometry. The RAW264.7 macrophages-HepG2 human hepatoma cancer cells Transwell co-culture system was established to investigate APS-SPIONs improve anti-tumor function of macrophages in vitro, and the proliferation activity of APS-SPIONs on RAW264.7 detected by cell counting kit-8 (CCK-8) method. The results showed that the average particle size and zeta potential of APS-SPIONs were (82.93 ± 1.47) nm and (-24.00 ± 0.47) mV. Polysaccharide and Fe content were 8.69% and 7.04%, respectively. APS-SPIONs effectively induced the polarization of RAW264.7 into M1 type in vitro, improving the anti-tumor ability of macrophages in a co-culture system, without effecting the proliferation of macrophages. Our study provides a drug development strategy and preliminary research results to educate macrophages and reshape the tumor immune microenvironment to achieve tumor-killing effects.

The active ingredient of traditional Chinese medicine, silybin (SBN), can inhibit the proliferation of cancer cells and enhance the anticancer effect of doxorubicin (DOX). However, due to non-targeting and short half-life of SBN and DOX, as well as different administration routes and pharmacokinetic processes, this combination drug cannot act on the tumor in the set order, seriously eliminating the synergistic effect between them and limiting the effect in vivo. Therefore, we intended to construct a nano-delivery system based on molybdenum disulfide (MoS₂), modified by polyethylene glycol (PEG) and sialic acid (SA), and co-loaded with SBN and DOX. The system induced the release of combined drugs under the dual-stimulation of pH and near infra-red (NIR), increased the free concentration of intracellular drugs, so as to achieve the synergistic effect between them. The animal welfare and experimental procedures were in accordance with the regulations of the Animal Ethics Committee of Fujian University of Traditional Chinese Medicine. MoS₂-PEG-SA-SBN/DOX circulated in vivo, and effectively accumulated at tumor sites through enhanced permeability and retention effect (EPR) and SA-mediated active targeting. Under near infrared light irradiation, MoS₂-PEG-SA-SBN/DOX realized the combination of synergistic chemotherapy and photothermal therapy for tumor, thus achieving excellent anti-tumor effect in vivo. This study can provide a new idea and strategy for the clinical treatment of lung cancer. Taken together, MoS₂-PEG-SA-SBN/DOX can offer a new idea and strategy for the clinical treatment of lung cancer.

Ribonucleic acid (RNA) medicines have strong therapeutic potential for numerous rare genetic illnesses and malignancies because of its exact programmability based on Watson-Crick base pairing principle and unique ability to regulate gene expression. However, RNA medicines still have limitations in many areas, including stability, half-life time, immunogenicity, organ selectivity, cellular uptake and endosomal escape efficiency despite their great therapeutic potentials. This review briefly introduced numerous RNA medications [mostly messenger RNA (mRNA), small interfering RNA (siRNA), microRNA (miRNA) and antisense oligonucleotide (ASO)] that have intrigued of researchers in recent years, as well as their action mechanism in vivo. A number of delivery techniques, such as chemical modification, ligands coupling and nanocarriers have been proposed. The manufacture and applications of lipid nanoparticle, polymer nanoparticle and exosomes were discussed in depth. The goal of this work is to give a theoretical foundation and design concepts for the development of effective and safe RNA delivery technology, as well as to facilitate RNA therapeutic clinical translation.

Since the application of biomedical nanotechnology in the field of drug delivery breathes new life into the research and development of high-end innovative agents, a substantial number of novel nano-drug delivery systems (nano-DDSs) have been successively developed and applied in the clinical practice. Among them, small molecule pure drug and prodrug-based nanoassemblies have grasped great attention, owing to the facile fabrication, ultrahigh drug loading and feasible industrial production. Herein, we provide an overview on the latest updates of small-molecule nanoassemblies. Firstly, the self-assembled prodrug-based nano-DDSs are introduced, including nanoassemblies formed by amphiphilic monomeric prodrugs, hydrophobic monomeric prodrugs and dimer monomeric prodrugs. Then, the recent advances on nanoassemblies of small molecule pure chemical drugs and biological drugs are presented. Furthermore, carrier-free small-molecule hybrid nanoassemblies of pure drugs and/or prodrugs are summarized and analyzed. Finally, the rational design, application prospects and clinical challenges of small-molecule self-assembled nano-DDSs are discussed and highlighted. This review aims to provide scientific reference for constructing the next generation of nanomedicines.

Gut microbiota is a complex and dynamic system, and is essential for the health of the body. As the "second genome" of the body, it can establish communication with the important organs by regulating intestinal nerves, gastrointestinal hormones, intestinal barrier, immunity and metabolism, thus affecting host′s physiological functions. Short chain fatty acid (SCFA), known as one important metabolite of intestinal microbiota, is regarded as a significant messenger of the gut-organ communication, due to its extensive regulation in the body′s immunity, metabolism, endocrine and signal transduction. In this review, we summarize the interaction between gut-liver/brain/kidney/lung axis and diseases, and focus on the role and mechanism of SCFA in the gut-organ communication, hoping to provide new ideas for the treatment of the related diseases.

In the research on cancer theranostics, most environment-sensitive drug delivery systems can only achieve unidirectional and irreversible responsive changes under pathological conditions, thereby improving the targeting effect and drug release performance of the delivery system. However, such irreversible changes pose potential safety hazards when the dynamically distributed delivery system returns to the blood circulation or transports to the normal physiological environment. Intelligent reversible drug delivery systems can respond to normal physiological and pathological microenvironments to achieve bidirectional and reversible structural changes. This feature will help to precisely control the drug release of the delivery system, prolong the blood circulation time, improve the targeting efficiency, and avoid the potential safety hazards of the irreversible drug delivery system. In this review, we describe the research progress of intelligent reversible drug delivery system from two main aspects: controlled drug release and prolonged blood circulation time/enhanced cellular internalization of drug.

Acute myeloid leukemia (AML) is a genetic heterogeneous disease in which primordial and juvenile myeloid cells proliferate or accumulate abnormally in bone marrow, peripheral blood and other tissues, resulting in damage to normal hematopoietic function. Studies have shown that about 30% of AML patients have FMS-like tyrosine kinase 3 (FLT3), FLT3 abnormal regulation is closely related to the occurrence and development of AML. At present, FLT3 has become an important target for developing small molecular targeted drugs. Currently, a variety of FLT3 inhibitors and FLT3 degraders have been developed targeting FLT3, and some compounds have exhibited good anti-AML activity. This article summarizes and sorts out the current mainstream drugs for AML therapeutic targeting FLT3, in order to provide a reference for the development and design of AML drugs.

Tumor microenvironment (TME) is composed of endothelial cells, pericytes, immune cells, cancer-associated fibroblasts (CAFs), cancer stem cells (CSCs), extracellular matrix (ECM) and other components of the complex biological environment. TME interacts with the tumor cells through a large amount of signaling pathways, participates in the process of tumor progression, invasion, and metastasis. Hence, TME has become a potential therapeutic target for cancer treatment, exhibiting excellent therapeutic potential and research value in the field of cancer treatment. Currently, the novel nanotechnology has been widely applied in anticancer therapy, and nanotechnology-mediated drug delivery system is being explored to apply in TME modulation to inhibit tumor progression. Nanotechnology-mediated drug delivery has many advantages over traditional therapeutic modalities, including longer circulation times, improved bioavailability, and reduced toxicity. This review summarized the research of targeted nano-drug delivery based on TME regulation, including regulation strategies based on CSCs, CAFs, immune cells, ECM, tumor vascularization, exosomes, and microbiota. In addition, we summarized the advantages, opportunities, and challenges of TME regulation strategy compared with traditional treatment strategy, which provides a reference for the application of nano-drug delivery system based on TME regulation strategy in tumor precision therapy.

Local anesthetic drugs are commonly used to block the conduction function of patient's nerves temporarily for anesthesia during surgery or to provide targeted analgesia after trauma. Compared with general anesthetics, local anesthetics makes less impact on the physiological status and alleviates pain complications in the presence of clear consciousness. However, its clinical application is still limited by its systemic toxicity, as well as toxicity to nerves and muscles, duration of action and lack of penetration. Nanotechnology can help it penetrate the physiological barrier, prolong the time of nerve block, and reduce toxic side effects. In addition, by building a light-responsive release system, local anesthetics can be released on demand, enhancing drug effectiveness and safety. However, in addition to the problems of poor consistency and high production costs, the system of light response release is still limited in application due to the limitation of the depth of penetration of the tissue. According to the current research progress, this paper briefly introduces and analyzes the main dosage forms, hoping to provide new ideas for the responsive release of local anesthetic drugs.

The function of the central nervous system was significantly altered under high-altitude hypoxia, and these changes lead to central nervous system disease and affected the metabolism of drugs in vivo. The blood-brain barrier is essential for maintaining central nervous system stability and plays a key role in the regulation of drug metabolism, and barrier structure and dysfunction affect drug transport to the brain. Changes in the structure and function of the blood-brain barrier and the transport of drugs across the blood-brain barrier under high-altitude hypoxia are regulated by changes in brain microvascular endothelial cells, astrocytes and pericytes, and are regulated by drug metabolism factors such as drug transporters and drug metabolizing enzymes. This article reviews the effects of high-altitude hypoxia on the structure and function of the blood-brain barrier and the effects of changes in the blood-brain barrier on drug metabolism. We investigate the regulatory effects and underlying mechanisms of the blood-brain barrier and related pathways such as transcription factors, inflammatory factors and nuclear receptors on drug transport under high-altitude hypoxia.