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Nanomaterials with renal clearance from the body within a reasonable timescale have shown great promises in the area of nanomedicine recently. However, the integration of theranostic and renal clearance properties into a single ultrasmall nanostructure remains a great challenge. Herein, meso-tetra(4-carboxyphenyl)porphyrin (TCPP) structure is utilized as a model, for the first time using noninvasive dynamic positron emission tomography (PET) imaging to investigate the balance of the renal clearance and tumor uptake behaviors of polyethylene glycol (PEG)-modified porphyrin nanoparticles (TCPP-PEG) with various molecular weights. This study finds that TCPP-PEG nanoparticles with larger molecular weight show higher tumor uptake due to the enhanced permeability and retention effect, while the lower ones tend to be better for renal clearance. Based on dynamic PET and fluorescence dual-modal imaging modalities, the TCPP-PEG10K nanoparticles seem to be an excellent choice for the balance of renal clearance and tumor retention. In vitro and in vivo photodynamic therapy confirms an excellent therapeutic efficacy. Therefore, this work presents a simplified approach to fabricate and select biocompatible multifunctional TCPP-PEG-based theranostic agents with renal clearance behavior, which highlights the clinical application potential of TCPP-PEG nanoparticles as theranostic probes for imaging-guided cancer therapy. [ABSTRACT FROM AUTHOR]

Photothermal therapy (PTT), as a minimally invasive and highly effective cancer treatment approach, has received widespread attention in recent years. Tremendous effort has been devoted to explore various types of photothermal agents with high near-infrared (NIR) absorbance for PTT cancer treatment. Despite many exciting progresses in the area, effective yet safe photothermal agents with good biocompatibility and biodegradability are still highly desired. In this work, a new organic PTT agent based on polyethylene glycol (PEG) coated micelle nanoparticles encapsulating a heptamethine indocyanine dye IR825 is developed, showing a strong NIR absorption band and a rather low quantum yield, for in vivo photothermal treatment of cancer. It is found that the IR825-PEG nanoparticles show ultra-high in vivo tumor uptake after intravenous injection, and appear to be an excellent PTT agent for tumor ablation under a low-power laser irradiation, without rendering any appreciable toxicity to the treated animals. Compared with inorganic nanomaterials and conjugated polymers being explored in PTT, the NIR-absorbing micelle nanoparticles presented here may have the least safety concern while showing excellent treatment efficacy, and thus may be a new photothermal agent potentially useful in clinical applications. [ABSTRACT FROM AUTHOR]

Recently, near-infrared (NIR) absorbing conjugated polymeric nanoparticles have received significant attention in photothermal therapy of cancer. Herein, polypyrrole (PPy), a NIR-absorbing conjugate polymer, is used to coat ultra-small iron oxide nanoparticles (IONPs), obtaining multifunctional IONP@PPy nanocomposite which is further modified by the biocompatible polyethylene glycol (PEG) through a layer-by-layer method to acquire high stability in physiological solutions. Utilizing the optical and magnetic properties of the yielded IONP@PPy-PEG nanoparticles, in vivo magnetic resonance (MR) and photoacoustic imaging of tumor-bearing mice are conducted, revealing strong tumor uptake of those nanoparticles after intravenous injection. In vivo photothermal therapy is then designed and carried out, achieving excellent tumor ablation therapeutic effect in mice experiments. These results promise the use of multifunctional NIR-absorbing organic-inorganic hybrid nanomaterials, such as IONP@PPy-PEG presented here, for potential applications in cancer theranostics. [ABSTRACT FROM AUTHOR]

A biocompatible complex has been prepared as gene carrier via electrostatic interaction, which is composed of a polycation, that is, poly[(dimethylamino)ethyl methacrylate] end-capped with cholesterol moiety (Chol-PDMAEMA30), along with a polyanion named poly(aspartic acid)-grafted-poly(ethylene glycol) (PASP-g-PEG). The complexes have less cytotoxicity compared to the case of alone Chol-PDMAEMA30 or branched polyethylenimine (PEI) system. In the present study, biocompatible complexes have been prepared as gene carrier via electrostatic interaction, which is composed of a polycation, that is, poly[(dimethylamino)ethyl methacrylate] end-capped with cholesterol moiety (Chol-PDMAEMA30), along with a polyanion named poly(aspartic acid)-grafted-poly(ethylene glycol) (PASP-g-PEG). We first synthesized polysuccinimide (PSI) via condensation polymerization of aspartic acid, and then used PEG-NH2 to react with the partial pentacyclic rings of PSI to yield a kind of graft copolymer polysuccinimide-grafted-poly(ethylene glycol) (PSI-g-PEG). After hydrolysis of the residual succinimide units, a new biodegradable and biocompatible graft copolymer PASP-g-PEG was prepared successfully. Chol-PDMAEMA30 was synthesized via oxyanion-initiated polymerization, as reported in our previous literature. We investigated the interactions between every pair among calf thymus DNA, Chol-PDMAEMA30, and PASP-g-PEG by agarose gel retardation assay. The results indicate that the prepared complexes could completely bind DNA and may become more stable during systemic circulation. The complexes have less cytotoxicity compared to the case of alone Chol-PDMAEMA30 or branched polyethylenimine (PEI) system. Furthermore, the physicochemical properties of the complexes were also investigated by zeta potential, transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements. These biodegradable and biocompatible polymeric carriers have potential applications in gene delivery. [ABSTRACT FROM PUBLISHER]

Abstract: We report a new strategy of using carrier-free pure near-infrared (NIR) dye nanoparticles (NPs) to achieve highly luminescent NIR fluorescent probes for in vitro and in vivo imaging. Bis(4-(N-(2-naphthyl)phenylamino) phenyl)-fumaronitrile (NPAPF) NPs are shown to exhibit favorable biocompatibility, wide-range pH stability (pH 4–10) and much more superior photostability than conventional dyes. Importantly, the combined merits of high dye loading content and aggregation-induced emission enhancement properties, endow the NIR probes with high brightness and a high quantum yield up to 14.9%. The NPAPF NPs can be readily conjugated with folic acid for targeted in vitro cell imaging. Applications of the NPs probes in high efficiency in vivo and ex vivo imaging were successfully demonstrated. Intense fluorescent signals of NPAPF NPs can be distinctly, selectively and spatially resolved in tumor sites with ultrahigh sensitivity, even with 5 ms exposure time, due to the preferentially accumulation of NPs in tumor sites through passive enhanced permeability and retention effect. The totality of results clearly demonstrate the exciting potential of the functionalized NPAPF NPs as a NIR fluorescent probe for in vitro and in vivo imaging and diagnostics. [Copyright &y& Elsevier]

Whether graphene and graphene oxide (GO) would affect the activities of bacteria has been under debate. Nevertheless, how graphene derivatives with biocompatible coatings interact with microorganisms and the underlying mechanisms are important issues for nanobiotechnology, and remain to be further explored. Herein, three new types of nano-GOs functionalized with polyethylene glycol (nGO-PEGs) were synthesized by varying the PEGylation degree, and their effects on Escherichia coli ( E. coli ) were carefully investigated. Interestingly, nGO-PEG (1:1), the one with relatively lower PEGylation degree, could significantly stimulate bacterial growth, whereas as-made GO and the other two nGO-PEGs showed no effect. Further analysis revealed that nGO-PEG (1:1) treatment significantly accelerated FtsZ-ring assembly, shortening Phase 1 in the bacterial cell cycle. Both DNA synthesis and extracellular polymeric substance (EPS) secretion were also dramatically increased. This unique phenomenon suggests promising potentials in microbial engineering as well as in clinical detection of bacterial pathogens. As a proof-of-concept, nGO-PEG (1:1) treatment could remarkably enhance (up to 6-fold) recombinant protein production in engineered bacteria cells. To our best knowledge, this is the first demonstration of functionalized GO as a novel, positive regulator in microbial engineering. Moreover, our work highlights the critical role of surface chemistry in modulating the interactions between nanomaterials and microorganisms. [ABSTRACT FROM AUTHOR]

Abstract: Ag2S quantum dots (QDs) have been demonstrated as a promising near-infrared II (NIR-II, 1.0–1.4 μm) emitting nanoprobe for in vivo imaging and detection. In this work, we carefully study the long-term in vivo biodistribution of Ag2S QDs functionalized with polyethylene glycol (PEG) and systematically examine the potential toxicity of Ag2S QDs over time. Our results show that PEGylated-Ag2S QDs are mainly accumulated in the reticuloendothelial system (RES) including liver and spleen after intravenous administration and can be gradually cleared, mostly by fecal excretion. PEGylated-Ag2S QDs do not cause appreciable toxicity at our tested doses (15 and 30 mg/kg) to the treated mice over a period of 2 months as evidenced by blood biochemistry, hematological analysis and histological examinations. Our work lays a solid foundation for further biomedical applications of Ag2S QDs as an important in vivo imaging agent in the NIR-II region. [Copyright &y& Elsevier]