Nano LIFE

Understanding nano–stem cell interactions plays a significant role in fostering both innovative and safe implementation of nanotechnology in stem cell research. Herein, we reviewed the recent advances of engineered nanomaterials and nanotechnologies in stem cell engineering and highlighted the key parameters that led to beneficial effects toward stem cell proliferation or differentiation. Meanwhile, we brought attention to the nanomaterials characteristics that contributed to toxic effects on stem cells with the hope to appeal balanced studies in the future by considering both the applications and implications of nanotechnologies.

Induced pluripotent stem cells (iPSCs) have a tremendous potential in biomedical applications. Nanotechnology has played an essential role on reprogramming iPSCs. In the current review, we will summarize recent progress on application of nanoparticles and other nanotechnology-based platforms in iPSC generation and in study of iPSC biology. We will also highlight the importance of nanotechnology on biomedical application of iPSCs.

Premature ovarian failure (POF) is a heterogeneous disorder characterized by amenorrhea, infertility, lack of estrogen, and elevated gonadotropin levels before the age of 40. Most POF females have fertility problems due to defects of germ cell development or complete ovarian failure. Though hormonal therapy could partially restore ovarian function, effects of these treatments are transient, much less for regeneration and repair of the ovaries. With the rise of regenerative medicine, stem cells transplantation gives new hope for repairing POF related ovaries damage. Studies from animal models indicate that stem cell transplantation can, at least in part, repair ovarian structure, improve ovarian function and fertility in POF, i.e., the bone marrow mesenchymal stem cells (BMSCs) and umbilical cord mesenchymal stem cells (UC-MSCs) can differentiate to ovaries and facilitate fertility recovery. However, the underlying mechanisms remain unclear, which limits their clinical applications. Here, we discuss the recent progress on the clinical applications of stem cells for POF treatment, which would become promising therapies for POF patients.

Incidence and mortality of liver disease has increased globally in recent years. Orthotopic liver transplantation is a well-developed, effective therapy even for the end-stage liver diseases. However, the application of the technique is limited by the short supply of donors and the complexity of orthotopic liver transplantation. Therefore, hepatocyte transplantation as a new therapeutic option was developed. Unfortunately, the routine supply of high quality human hepatocytes was also restricted and the liver donor was lacking, too. Thus, exploration and study for available and renewable sources of nondonor hepatocytes are both necessary and important. Researches have proved that nondonor hepatocyte-like cells can be derived from various types of cells including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), liver stem cells (LSCs), fibroblasts by lineage reprogramming, hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). In this review, we describe recent advances in the field of the cell therapy in liver regeneration. In addition, we also discuss the existing restrictions in these types of therapies and ongoing developments.

Hepatocyte transplantation has been proved an effective method to help liver regeneration by replacing host deficient cells caused by various disorders or injuries. However, several problems existing in hepatocyte transplantation have limited the clinical application of the technology. These problems include limited survival time of transplanted cells, immune rejection in xenotransplantation and insufficient transplantation efficiency. The rapid development of nanotechnology provides an opportunity for solving these problems. Application of nanomaterials in liver regeneration has been frequently reported recently. According to these researches, nanomaterials have advantages on the aspects of helping cell adhesion and growth, maintaining cell function and inducing cell differentiation. What is more, nanomaterials also exhibited its advantage on cell migration tracking, thus could help to monitor the cells transplantation and noninvasive diagnosis. For the further application of nanomaterials in liver regeneration, a complete understanding of current progress will be necessary and helpful. Our goal in this review is to summarize the current status of the applications of nanomaterials in hepatocyte transplantation. We will focus on nanomaterials that acted as scaffolds for hepatocyte growth and function maintenance, delivery cargo for improving hepatocyte transplantation and trackers for in vivo monitoring.

We report a sandwich immunoassay strategy for specific isolation and detection of cancer cells. Prostate cancer LNCaP cells overexpressing PSMA (Prostate-specific membrane antigen) were used as the model target to evaluate the performance of immunoassay. Inorganic/polymer nanocomposites with Janus-like structure and enhanced fluorescence properties were synthesized and applied for immobilization of QDs and the antibodies. PSMA antibodies were covalently conjugated to the QDs@SiO₂/PS Janus-like composite nanoparticles to construct the fluorescent probes. Magnetic probes conjugated with polyclonal antibodies were used to capture and isolate the cancer cells. Results indicated high potential of the unique nanoprobes in specific isolation and detection of cancer cells.

Stem cells possess great potential for tissue regeneration due to their infrequent capability to differentiate into specialized some other cell lines. The progress of nanomaterials has been remarkable in recent years. Nanomaterials control cellular response by endocytosis, acting as scaffolding roles or nanocarriers and regulating extracellular matrix (ECM). Furthermore, some nanomaterials have outstanding optical and magnetic properties, so can be used for stem cells labeling and imaging which plays an essential role in defining the mechanisms governing stem-cells therapeutics. In this review, focus is put on recent developments in controlling the fate of stem cells and stem cells labeling and imaging by nanomaterials. The effect of nanomaterials based inorganic nanomaterials (e.g., carbon nanotubes, mesoporous silica nanoparticles, gold nanoparticles, etc.), organic materials (nanoscale topography), on the differentiation of mesenchymal stem cells, embryonic stem cells and cancer stem cells will be discussed. Optical imaging (fluorescence and up-conversion luminescence), magnetic resonance imaging and multimodal imaging by nanomaterials of stem cells will also be introduced.

Cardiovascular disease remains the single highest global cause of death and a significant financial burden on the healthcare system. Despite the advances in medical treatments, the prevalence and mortality for heart failure remain unacceptably high. New approaches are urgently needed to reduce this burden and improve patient outcomes and quality of life. One such promising approach is stem cell therapy, including embryonic stem cells, bone marrow derived stem cells, induced pluripotent stem cells and mesenchymal stem cells. However, the cardiac microenvironment following myocardial infarction poses huge challenges with inflammation, adequate retention, engraftment and functional incorporation all crucial concerns. The lack of cardiac regeneration, cell viability and functional improvement has hindered the success of stem cell therapy in clinical settings. The use of biomaterial scaffolds in conjunction with stem cells has recently been shown to enhance the outcome of stem cell therapy for heart failure and myocardial infarction. This review outlines some of the current challenges in the treatment of heart failure and acute myocardial infarction through improving stem cell therapeutic strategies, as well as the prospect of suitable biomaterial scaffolds to enhance their efficacy and improve patient clinical outcomes.