In the past few years, conjugated polymer nanoparticles (CPNs) have been successfully prepared and applied in the biological field because of their unique opto-electronic properties. The rapid ...development of CPNs is mainly attributed to their simple synthesis procedures and easy separation steps. The advantages of CPNs include high brightness, excellent photostability, low cytotoxicity, high quantum yield and versatile surface modification. The functionalization of CPNs with specific recognition elements imparts them good ability for targeted recognition and imaging
in vitro
and
in vivo
. CPNs can be applied to deliver drug and gene, and simultaneously to real-time monitor the release process due to their self-luminous characteristics. Moreover, CPNs can sensitize oxygen molecules to generate reactive oxygen species (ROS) which can kill adjacent bacteria and tumor cells. In this
tutorial review
, we provide a recent development of the preparation methods, properties, and functionalization strategies of CPNs, especially discussing their biological applications in targeted imaging, drug/gene delivery and biomedicine. The challenges and outlooks in this field will also be discussed.
This review provides an overview of the latest advancement in preparation, properties, functionalization and biological applications of conjugated polymer nanoparticles.
Anticancer modalities based on oxygen free radicals, including photodynamic therapy and radiotherapy, have emerged as promising treatments in the clinic. However, the hypoxic environment in tumor ...tissue prevents the formation of oxygen free radicals. Here we introduce a novel strategy that employs oxygen‐independent free radicals generated from a polymerization initiator for eradicating cancer cells. The initiator is mixed with a phase‐change material and loaded into the cavities of gold nanocages. Upon irradiation by a near‐infrared laser, the phase‐change material is melted due to the photothermal effect of gold nanocages, leading to the release and decomposition of the loaded initiator to generate free radicals. The free radicals produced in this way are highly effective in inducing apoptosis in hypoxic cancer cells.
Oxygen‐independent free radicals: Gold nanocages filled with a phase‐change material (green patches in picture) are used as a carrier for the radical source AIPH (blue circles) to achieve controlled generation of free radicals. The process is oxygen‐independent and can be used for the therapy of hypoxic cancer.
A smart release system responsive to near‐infrared (NIR) light is developed for intracellular drug delivery. The concept is demonstrated by coencapsulating doxorubicin (DOX) (an anticancer drug) and ...IR780 iodide (IR780) (an NIR‐absorbing dye) into nanoparticles made of a eutectic mixture of naturally occurring fatty acids. The eutectic mixture has a well‐defined melting point at 39 °C, and can be used as a biocompatible phase‐change material for NIR‐triggered drug release. The resultant nanoparticles exhibit prominent photothermal effect and quick drug release in response to NIR irradiation. Fluorescence microscopy analysis indicates that the DOX trapped in the nanoparticles can be efficiently released into the cytosol under NIR irradiation, resulting in enhanced anticancer activity. A new platform is thus offered for designing effective intracellular drug‐release systems, holding great promise for future cancer therapy.
A smart system responsive to near‐infrared (NIR) light is developed by coencapsulating a drug and an NIR‐absorbing dye into nanoparticles made of a eutectic mixture of naturally occurring fatty acids. Photothermal heating under NIR irradiation facilitates rapid and efficient intracellular drug release, leading to enhancement in anticancer activity.
Sensing temperature at the subcellular level is of great importance for the understanding of miscellaneous biological processes. However, the development of sensitive and reliable organic fluorescent ...nanothermometers remains challenging. In this study, we report the fabrication of a novel organic fluorescent nanothermometer and study its application in temperature sensing. First of all, we synthesize a dual-responsive organic luminogen that can respond to the molecular state of aggregation and environmental polarity. Next, natural saturated fatty acids with sharp melting points as well as reversible and rapid phase transition are employed as the encapsulation matrix to correlate external heat information with the fluorescence properties of the luminogen. To apply the composite materials for biological application, we formulate them into colloidally dispersed nanoparticles by a technique that combines in situ surface polymerization and nanoprecipitation. As anticipated, the resultant zwitterionic nanothermometer exhibits sensitive, reversible, reliable, and multiparametric responses to temperature variation within a narrow range around the physiological temperature (i.e., 37 °C). Taking spectral position, fluorescence intensity, and fluorescence lifetime as the correlation parameters, the maximum relative thermal sensitivities are determined to be 2.15% °C–1, 17.06% °C–1, and 17.72% °C–1, respectively, which are much higher than most fluorescent nanothermometers. Furthermore, we achieve the multimodal temperature sensing of bacterial biofilms using these three complementary fluorescence parameters. Besides, we also fabricate a cationic form of the nanothermometer to facilitate efficient cellular uptake, holding great promise for studying thermal behaviors in biological systems.
This communication describes a simple and effective method for welding electrospun nanofibers at the cross points to enhance the mechanical properties of their nonwoven mats. The welding is achieved ...by placing a nonwoven mat of the nanofibers in a capped vial with the vapor of a proper solvent. For polycaprolactone (PCL) nanofibers, the solvent is dichloromethane (DCM). The welding can be managed in a controllable fashion by simply varying the partial pressure of DCM and/or the exposure time. Relative to the pristine nanofiber mat, the mechanical strength of the welded PCL nanofiber mat can be increased by as much as 200%. Meanwhile, such a treatment does not cause any major structural changes, including morphology, fiber diameter, and pore size. This study provides a generic method for improving the mechanical properties of nonwoven nanofiber mats, holding great potential in various applications.
A simple and versatile method is developed to improve the mechanical properties of electrospun nanofiber mats by welding the nanofibers at their cross points. Such a treatment does not induce significant structural changes, including the average diameter of the fibers and pore size.
A multifunctional cationic poly(p‐phenylene vinylene) derivate with polyethylene glycol (PEG) side chains is used for selective recognition, imaging, and killing of bacteria over mammalian cells. ...This material exerts a far‐reaching impact on the future development of antimicrobial materials and has potential applications in pathogen infections and medical implants.
Except for chemotherapy, surgery, and radiotherapy, photodynamic therapy (PDT) as new therapy modality is already in wide clinic use for the treatment of various diseases. The major bottleneck of ...this technique is the requirement of outer light source, which always limits effective application of PDT to the lesions in deeper tissue. Here, we first report a new modality for treating cancer and microbial infections, which is activated by chemical molecules instead of outer light irradiation. In this system, in situ bioluminescence of luminol can be absorbed by a cationic oligo(p-phenylene vinylene) (OPV) that acts as the photosensitizer through bioluminescence resonance energy transfer (BRET) process. The excited OPV sensitizes oxygen molecule in the surroundings to produce reactive oxygen species (ROS) that kill the adjacent cancer cells in vitro and in vivo, and pathogenic microbes. By avoiding the use of light irradiation, this work opens a new therapy modality to tumor and pathogen infections.
There are 202 electrolytic manganese metal (EMM) industries in China with a total capacity of 1.88
million tons in 2008. This accounts for 98.58% of the world's overall capacity of EMM production. ...The industries generate a huge number of pollutants. To ascertain the factors causing these pollutants in the EMM industries in China, and cost-effective ways to reduce this pollution, a study was carried out at one of the largest Chinese EMM industries with the best operation practice from September 2005 to June 2007. Material and substance balances were established on the basis of gathering data through on-site measurement and auditing. Analyses of the pollution materials were subsequently conducted.
The results showed: (1) for manganese, 71.9% enters the product, i.e. electrolytic manganese, 12.6% enters anode mud, 13.7% enters residues and 1.8% enters wastewater (before treatment); (2) for chromium, 2.4% enters the product and 97.6% enters wastewater; (3) for selenium, 60.7% enters the product, 22.3% enters anode mud and 17% enters residues; (4) for ammonia, 52.36% enters wastewater, 1.19% enters anode mud, 44.09% enters residues and 2.36% was evaporated and (5) for SO
4
2−, 44.5% enters wastewater, 0.2% enters anode mud and 55.3% enters residues. Manganese residues are the largest and most dangerous waste stream of the EMM industry. Use of selenium in large quantities constitutes potentially severe environmental risks. The best way to curtail environmental pollution from the industry is to apply new and modern technologies to cut off the pollution before it is generated.
The emergence of the aggregation-induced emission (AIE) concept significantly changes the cognition of the scientific community toward classic photophysical phenomena. More importantly, the AIE ...phenomenon has brought huge opportunities for the analysis of bioactive species, the monitoring of complicated biological processes, and the elucidation of key physiological and pathological behaviors. As a class of promising luminescent materials, AIE luminogens (AIEgens) are weakly or non-emissive in the form of isolated molecular species but emit particularly strong fluorescence in the aggregated and solid states. Motivated by the prominent advantages such as high brightness, large Stokes shift, excellent photostability, and good biocompatibility, AIEgen-based bioprobes have been widely explored in the field of biomedicine. This review aims to provide a systematic summary of the developmental history and an in-depth perspective of the current landscape of AIE in the biomedical field, with an emphasis on the discussions of major working principles. The milestones of the historical development of AIE in the biomedical field are first reviewed. A total of four major research directions are then extracted, including biomacromolecule sensing (at the molecular level), in vitro cell imaging (at the cellular level), in vivo imaging (at the animal level), and cancer theranostics (at the cellular and animal levels), together with clear-cut tables showing comprehensive cases for further study. Lastly, this review is concluded by the discussions of several perspectives on future directions. It is believed that AIEgen-based bioprobes will play vital roles in the exploration of mysterious life processes by integration with various cutting-edge modalities and techniques with an ultimate goal of addressing more healthcare issues.
PDF
