Monitoring viral loads in sewage can reflect the prevalence of infections within communities to a certain extent. Methods for concentrating and enriching viruses in sewage are also rapidly evolving. The magnetic bead method has been widely adopted for nucleic acid extraction due to its simplicity and high efficiency. In this study, we designed three pre-treatment procedures (T1: sedimentation for 30 min; T2: low-speed centrifugation at 2500×g for 5 min; T3: high-speed centrifugation at 8000×g for 5 min) to identify the optimal pre-treatment for enhancing viral nucleic acid concentration efficiency using the magnetic bead method. Spiked recovery tests were employed to compare the concentration efficiency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in sewage between the magnetic bead method and the traditional polyethylene glycol (PEG) precipitation method. Real sewage samples were further used to evaluate both methods for enriching enveloped viruses (SARS-CoV-2, influenza virus) and non-enveloped viruses (Norovirus, Rotavirus, Adenovirus). Results demonstrated that low-speed centrifugation (T2) served as the optimal pre-treatment for the magnetic bead-based concentration. The high-throughput magnetic bead method achieved significantly higher recovery rates for SARS-CoV-2, Norovirus, and Adenovirus compared to PEG precipitation. Thus, the high-throughput magnetic bead method can be widely applied for the concentration and concentration of diverse viruses in sewage.

Photothermal therapy (PTT) against cancer not only directly ablates tumors but also induces tumor immunogenic cell death (ICD). However, the antitumor immune response elicited by ICD is insufficient to prevent relapse and metastasis because of the immunosuppressive tumor microenvironment (TME). A biomimetic nanoplatform (bmNP) mimicking cytotoxic lymphocytes (CTLs) for combinational photothermal-immunotherapy to effectively regulate the immunosuppressive TME is reported here. The bmNP is constructed by wrapping the T-cell membrane onto a new type of photothermal agents, spherical Au-based PNCs (sAuPNCs). Similar to T-cells, the bmNP enhanced accumulation at the tumor site by targeting the tumor via adhesion proteins on T-cell membrane. The obtained sAuPNCs have a wide absorption band in the second near-infrared (NIR-II) region with a high photothermal conversion efficiency (PCE) up to about 75% and excellent photostability. The bmNP with a smaller size is more superior compete with T-cells to bond with tumor cells via PD-1/PD-L1 interaction to effectively block the PD-1 checkpoint of T-cells for preventing T-cell exhaustion. Furthermore, in vivo studies reveal the immunological memory effect is significantly elicited in mice received bmNPs therapy. Collectively, bmNPs show great potential in photothermal-enhanced immunotherapy.

Conjugated polymers (CPs) have attracted much attention in the fields of chemistry, medicine, life science, and material science. Researchers have carried out a series of innovative researches and have made significant research progress regarding the unique photochemical and photophysical properties of CPs, expanding the application range of polymers. CPs are polymers formed by the conjugation of multiple repeating light-emitting units. Through precise control of their structure, functional molecules with different properties can be obtained. Fluorescence probes with different absorption and emission wavelengths can be obtained by changing the main chain structure. By modifying the side chain structure with water-soluble groups or selective recognition molecules, electrostatic interaction or specific binding with specific targets can be achieved; subsequently, the purpose of selective recognition can be achieved. This article reviews the research work of CPs in cell imaging, tumor diagnosis, and treatment in recent years, summarizes the latest progress in the application of CPs in imaging, tumor diagnosis, and treatment, and discusses the future development direction of CPs in cell imaging, tumor diagnosis, and treatment.

Photothermal therapy (PTT) has received constant attention as a promising cancer treatment. However, PTT-induced inflammation can limit its effectiveness. To address this shortcoming, we developed second near-infrared (NIR-II) light-activated nanotheranostics (CPNPBs), which include a thermosensitive nitric oxide (NO) donor (BNN6) to enhance PTT. Under a 1064 nm laser irradiation, the conjugated polymer in CPNPBs serves as a photothermal agent for photothermal conversion, and the generated heat triggers the decomposition of BNN6 to release NO. The combination of hyperthermia and NO generation under single NIR-II laser irradiation allows enhanced thermal ablation of tumors. Consequently, CPNPBs can be exploited as potential candidates for NO-enhanced PTT, holding great promise for their clinical translational development.

Abstract Background Phototherapy, a promising chemotherapy alternative, has been widely utilized for cancer treatment. However, heat shock protein (HSP70) mediated-heat tolerance in photothermal therapy (PTT), and the attenuated therapeutic effect of photodynamic therapy (PDT) in the hypoxic tumor microenvironment still limit its clinical applications, where both processes are intimately linked to energy metabolism. Results We designed a site-specific nanoplatform (CS@ATO/CHC/T780 NPs) modulating energy metabolism to down-regulate the expression of HSP70 and alleviate hypoxia for enhanced phototherapy by integrating a mitochondria-targeted triphenylphosphine (TPP) derivative (T780), mitochondrial electron transport chain inhibitor atovaquone (ATO) and monocarboxylic acid transporter 1 (MCT1) inhibitor α-cyano-4-hydroxycinnamate (CHC), and modified with chondroitin sulfate (CS). Mechanistically, CS and TPP-tailored IR780 were used to achieve site-specific delivery to tumor tissues and mitochondria in tumor cells, respectively. After efficient cellular internalization, the nanoplatform could effectively disassemble to release cargoes in the acid tumor microenvironment. ATO, a mitochondrial electron transport chain complex III inhibitor, could reduce the production of intracellular adenosine triphosphate (ATP) and further downregulate the expression of HSP70 to overcome the thermo-resistance of PTT. Meanwhile, CHC could reduce the uptake rate of lactic acid (LA) to save oxygen consumption for improving the effectiveness of PDT. Conclusion The CS@ATO/CHC/T780 NPs exhibits excellent anticancer activity and good biosafety in vitro and in vivo, providing a prospective strategy for efficient phototherapy by manipulating energy metabolism.

For cancer treatment, nanocarriers were designed with cationic lipids and polymers to improve the cytosolic delivery efficiency of siRNA. Though the positively charged nanocarriers showed great potential for RNA therapy, it was inevitable to generate the potential cytotoxicity. We constructed a pH-responsive nanoplatform, which co-carried siRNA and anticancer drug (hydroxycamptothecine, HCPT), to integrate gene therapy and chemotherapy for combination cancer therapy. The fluorescent conjugated polymer nanoparticles (CPNPs) modified with cell-penetrating peptides were employed as cores to carry siRNA molecules (siRNA-CPNPs) and track the biodistribution of nanotherapeutics by virtue of fluorescence. Calcium phosphate (CaP) nanocoatings were deposited on the surface of siRNA-CPNPs, followed by loading with HCPT and aptamers targeting cancer cells to obtain a targeted and tumor acid-responsive biocompatible nanoplatform. After the uptake of cancer cells, the CaP nanocoatings were decomposed in the acidic endo/lysosomes to release HCPT, and the siRNA-CPNPs were exposed to facilitate the siRNA endo/lysosome escape and cytoplasm delivery. Results obtained from both in vitro and in vivo studies in tumor inhibition expressed that the combined therapy exhibited a better therapeutic efficacy than any monotherapy.

As a widely used anticancer drug, doxorubicin (DOX) could induce cell death mainly via interfering with DNA activity; thus, DOX could perform therapeutic effects mainly in the cell nucleus. However, most of the reported drug delivery systems lacked the well localization in the nucleus and released DOX molecules into the cytoplasm. Due to formidable barriers formed in the nuclear envelope, only around 1% of DOX could reach the nucleus and keep active. Therefore, DOX molecules were inevitably overloaded to achieve the desired therapeutic efficacy, which would induce serious side effects. Herein, we developed a highly localized drug nanocarrier for in situ release of DOX molecules to their action site where they could directly interfere with the DNA activity. In this work, we used cationic polymer-modified upconversion nanoparticles (UCNPs) as the luminescence core and gene carrier, while aptamers served as the DNA nanotrain to load DOX. Finally, the prepared nanotheranostic agent displayed good targetability, high cell apoptosis ratio (93.04%) with quite lower concentration than the LC50 of DOX, and obvious inhibition on tumor growth.

The diagnosis and treatment of major diseases, especially tumors, was the key to improving the cure rate and survival rate of patients. Therefore, one of the main goals of modern medicine was to develop effective, non-toxic treatments. This paper successfully established dipeptide nanoparticles/clofarabine/aptamer AS1411/influenza hemagglutinin peptide/siRNA/doxorubicin (DNPs/Clolar/AS1411/HA/RNA/DOX) multi-functional nano particles for specific delivery, cancer treatment and bioimaging. It was an ideal choice for multi-drug synergy treatment. First, non-toxic DNPs formed by self-assembly of dipeptides with safe and biocompatible effect. Second, from the perspective of the multi-functional nanoparticles for nano-drug tumors imaging monitoring, AS1411 and HA were used as cell permits for enhancing the specificity of cell drug delivery ability and improving the endosomal escape, respectively. Third, the multi-functional nanoparticles with Clolar, siRNA and DOX, three drug synergistic treatments were used to improve the therapeutic effect of tumors. Both cell experiments and vivo experiments demonstrated that the synergistic treatment of the multi-drugs was superior to the effect of single-drug therapy. Thus, the proposed multi-functional nanoparticles have initiated new ideas for these hybrid anticancer drugs based on peptide self-assembled nanocarriers and its widely applications in biomedicine.

The constructed nanoplatform not only retained the outstanding fluorescence properties and biocompatibility but also enhanced delivery efficiency of siRNA.

During the past decade, semiconducting polymer dots (Pdots) have been prevailing in the family of fluorescent probes due to its high photon budget, excellent photo stability, and good biocompatibility. In this study, holo-Transferrin human (Tf) was utilized to covalently couple with Pdots for a highly efficient endocytosis process through transferrin receptors (TfRs) mediated internalization. As a result, the endocytosis efficiency of Tf-conjugated Pdots in HeLa cells dramatically increased as compared to that of unconjugated Pdots in the same condition. This acute increment demonstrates that holo-Transferrin molecules are of great capability for intracellular delivery of Pdots to TfRs overexpressed cells. The transportation route of Tf-conjugated Pdots is quite different from the uptake mechanism of unconjugated Pdots via nonspecific endocytic trafficking pathway. Considering the overexpression of TfRs in various cancer cells, Tf-conjugated Pdots hold potential to function as a nanocarrier for efficient drug delivery in cancer diagnostics and therapy.

Stem cell therapy is rapidly moving toward translation to clinical application. To elucidate the therapeutic effect, a robust method that allows tracking of the stem cells over an extended period of time is required. Herein, semiconducting polymer dots (Pdots) are demonstrated for their use in bright labeling and tracking of human mesenchymal stem cells (MSCs) in vitro and in vivo. The Pdots coated with a cell-penetrating peptide (R8) showed remarkable endocytic uptake efficiency that was 15 times higher than that of carboxyl Pdots and more than 200 times than that of bare Pdots. The Pdot-labeled MSCs can be traced for 15 generations in vitro and tracked over 2 weeks in vivo after subcutaneous transplantation. The labeled MSCs administered through the tail vein were preferentially accumulated in the lung; this was distinctive from the distribution of free Pdots, which were primarily distributed in the liver. Based on the properties of bright labeling, excellent tracking capability, and great biocompatibility, the Pdots will be valuable in the applications of stem cell biology and regenerative medicine.

Stem cell therapy holds promise for treatment of intractable diseases and injured organs. For clinical translation, it is pivotal to understand the homing, engraftment, and differentiation processes of stem cells in a living body. Here we report near-infrared (NIR) fluorescent semiconductor polymer dots (Pdots) for bright labeling and tracking of human mesenchymal stem cells (MSCs). The Pdots exhibit narrow-band emission at 775 nm with a quantum yield of 22%, among the highest value for various NIR probes. The Pdots together with a cell penetrating peptide are able to track stem cells over two weeks without disturbing their multipotent properties, as confirmed by the analyses on cell proliferation, differentiation, stem-cell markers, and immunophenotyping. The in vivo cell tracking was demonstrated in a liver-resection mouse model, which indicated that the Pdot-labeled MSCs after tail-vein transplantation were initially trapped in lung, gradually migrated to the injured liver, and then proliferated into cell clusters. Liver-function analysis and histological examination revealed that the inflammation induced by liver resection was apparently decreased after stem cell transplantation. With the bright labeling, superior biocompatibility, and long-term tracking performance, the Pdot probes are promising for stem cell research and regenerative medicine.

Small molecules participate extensively in various life processes. However, specific and sensitive detection of small molecules in a living system is highly challenging. Here, we describe in vivo real-time dynamic monitoring of small molecules by a luminescent polymer-dot oxygen transducer. The optical transducer combined with an oxygen-consuming enzyme can sensitively detect small-molecule substrates as the enzyme-catalyzed reaction depletes its internal oxygen reservoir in the presence of small molecules. We exemplify this detection strategy by using glucose-oxidase-functionalized polymer dots, yielding high selectivity, large dynamic range, and reversible glucose detection in cell and tissue environments. The transducer-enzyme assembly after subcutaneous implantation provides a strong luminescence signal that is transdermally detectable and continuously responsive to blood glucose fluctuations for up to 30 days. In view of a large library of oxygen-consuming enzymes, this strategy is promising for in vivo detection and quantitative determination of a variety of small molecules.

We investigated the cellular uptake behavior and cell viability of semiconducting polymer dots (Pdots) on human gastric adenocarcinoma (SGC-7901) cells and human gastric mucosal (GES-1) cells. MTT studies indicate the Pdot treatment induces obvious cell proliferation in both types of cell lines. We performed further investigations such as reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) change, which indicate that the cell proliferation is in good agreement with the increase in the ROS and MMP levels. Moreover, expression of protein kinase B (Akt) decreased as the Pdot concentration increases, but the expression of protein dual-phosphorylated Erk (p-Erk) and phosphorylated c-Jun N-terminal kinases (p-JNK) were increased. These effects indicated that the Pdots could promote the growth of SGC-7901 cells and GES-1 cells by appropriately regulating the expressions of protein Akt, p-Erk, and p-JNK.

We report on a europium-complex-grafted polymer for preparing stable nanoparticle probes with high luminescence brightness, narrow emission bandwidth, and long luminescence lifetimes. A Eu complex bearing an amino group was used to react with a functional copolymer poly(styrene-co-maleic anhydride) by the spontaneous amidation reaction, producing the polymer grafted with Eu complexes in the side chains. The Eu-complex-grafted polymer was further used to prepare Eu-complex-grafted polymer dots (Pdots) and Eu-complex-blended poly(9-vinylcarbazole) composite Pdots, which showed improved colloidal stability as compared to those directly doped with Eu-complex molecules. Both types of Pdots can be efficiently quenched by a nile blue dye, exhibiting much lower detection limit and higher quenching sensitivity as compared to free Eu-complex molecules. Steady-state spectroscopy and time-resolved decay dynamics suggest the quenching mechanism is via efficient fluorescence resonance energy transfer from the Eu complex inside a Pdot to surface dye molecules. The amplified quenching in Eu-complex Pdots, together with efficient cell uptake and specific cell surface labeling observed in mammalian cells, suggests their potential applications in time-resolved bioassays and cellular imaging.

采用纳米沉淀法制备了半导体聚合物CN-PPV纳米粒子,并用改进的Stber方法对纳米粒子进行包覆,获得了发光稳定的SiO2/CN-PPV纳米粒子。用动态光散射(DLS)及透射电镜(TEM)方法对粒子尺寸进行了表征,结果表明包覆前的CN-PPV纳米粒子平均粒径约为30 nm,包覆获得SiO2/CN-PPV纳米粒子的平均粒径约为60 nm。通过紫外-可见吸收光谱及荧光光谱对包覆前后纳米粒子的发光性质进行了比较,发现共轭聚合物CN-PPV包覆后的发射光谱与包覆前相比发生了小的蓝移,表明共轭聚合物的分子构型可能发生了微小变化。SiO2包覆可以提高聚合物发光分子的光稳定性,并且提供用于生物分子耦联的表面,这类材料有望在生物医学成像中获得应用。

We report a ratiometric fluorescent sensor based on semiconducting polymer dots chelated with terbium ions to detect bacterial spores in aqueous solution. Fluorescent polyfluorene (PFO) dots serve as a scaffold to coordinate with lanthanide ions that can be sensitized by calcium dipicolinate (CaDPA), an important biomarker of bacterial spores. The absorption band of PFO dots extends to deep UV region, allowing both the reference and the sensitizer can be excited with a single wavelength (~275 nm). The fluorescence of PFO remains constant as a reference, while the Tb(3+) ions exhibit enhanced luminescence upon binding with DPA. The sharp fluorescence peaks of β-phase PFO dots and the narrow-band emissions of Tb(3+) ions enable ratiometric and sensitive CaDPA detection with a linear response over nanomolar concentration and a detection limit of ~0.2 nM. The Pdots based sensor also show excellent selectivity to CaDPA over other aromatic ligands. Our results indicate that the Tb(3+) chelated Pdots sensor is promising for sensitive and rapid detection of bacterial spores.