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Photocontrolled polymerization offers a convenient way to direct the reaction progress and tailor the polymer structures. Nevertheless, conjugated polymers are yet to be utilized as the photocatalyst in associated reactions. Herein, we employed poly(boron dipyrromethene

Due to the excellent properties including high specificity, low side-effect and good biocompatibility, conjugated polymer nanomaterials have been served as efficient anticancer reagents in the past decades. According to the developed anticancer systems based on conjugated polymer nanomaterials, it could be summarized into three main cancer therapy strategies: photodynamic therapy(PDT), photothermal therapy(PTT) and combination therapy. In this mini review, we provide a brief introduction to three different cancer therapy modes, their mechanisms and potential biological applications. Furthermore, some perspectives on the further development of conjugated polymer nanomaterials are proposed in the territory of anticancer precision medicine.

Molecular biomarkers, especially DNA methylation, are crucial discoveries for early detection of cancer. Compared with a single biomarker detection mode, using the conjoint detection mode can allow researchers to easily assess the association of the biomarkers with specific cancer. In this paper, we calculated the methylation status of

In this work, we designed and synthesized a new cationic conjugated polyfluorene tagging with phenylboronic acid groups (PFP–PBA) for controllable cell membrane imaging. By balancing the synergistic effect of dynamic covalent bonds and electrostatic interactions between positively charged PFP–PBA and negatively charged cell membrane, the controllable cell membrane imaging could be realized. These findings demonstrated that conjugated polymers could be used as effective materials for regulating interactions with cells to develop controllable self-assembly systems for various biological applications.

Hydrogen-bonded drug conjugation is highly expected as the next-generation smart therapeutic agent that remains stable in biological medium. A carrier design strategy of hydrogen-bonded drug conjugates as pendants in conjugated polymer nanogel is developed. The H-bond acceptor uracil-functionalized poly(

Cationic conjugated polymers (CCPs) have been attracting a lot of attention in biomedical applications because of their good photoelectric properties and good cell viability. However, positively charged components may reduce the electrostatic repulsion among red blood cells (RBCs) and induce RBC aggregation, which may lead to thrombus. Herein, in this work, we prepared the complexes of CCPs and outer membrane vesicles (OMVs) to inhibit RBC aggregation induced by CCPs and improve the biocompatibility of CCPs. A poly(fluorene-co-phenylene) derivative (PFP), a poly(p-phenylenevinylene) derivative (PPV), and a poly(thiophene) derivative (PMNT) were chosen as the model CCPs, and OMVs were used as the representative of a cell membrane. The CCP–OMV complexes were formed mainly driven by electrostatic interactions. Besides, the electrostatic CCP–OMV complexes were proved to be able to prevent the RBC aggregation induced by CCPs while maintaining the hydrophobic interactions between CCPs and RBCs.

Misfolding and abnormal assembly of proteins cause many intractable diseases. The modulation of the assembly process of these proteins could contribute to understanding and controlling amyloid protein aggregation. Previous works focused mainly on the inhibition of the assembly process. To broaden the interaction modality of modulators with proteins for developing new modulators, in this work, we designed and synthesized two reactive poly ( p-phenylene vinylene) polymers, respectively, functionalized with N-hydroxysuccinimide ester (PPV-NHS) and pentafluorophenol ester (PPV-PFP), which exhibited the prevention or co-assembly effect on the aggregation process of islet amyloid polypeptide (IAPP). Cell assays demonstrated that both of the two polymers could effectively eliminate the cytotoxicity of IAPP. Moreover, PPV-NHS also could irreversibly disrupt preformed IAPP fibrils. We envision that PPV-NHS and PPV-PFP might offer a new design method for the modulation of protein assembly.

Cell surface engineering with functional polymers is an effective strategy to modulate cell activity. Here, a bio-palladium catalyzed polymerization strategy was developed for in situ synthesis of conjugated polymers on living cell surfaces. Through Sonagashira polymerization, photoactive polyphenyleneethynylene (PPE) is synthesized on the cell surface via cell-generated bio-Pd catalyst. The in situ formed PPE is identified by excellent light-harvest capacity and blue fluorescence on the surfaces of E. coli and C. pyrenoidosa. Besides imaging microbes for tracing the polymerization process, PPE also exhibits enhanced antibacterial activity against E. coli. It can also augment the ATP synthesis of C. pyrenoidosa through enlarging the light absorption and accelerating the cyclic electron transport of the algae. With this bio-metal catalyzed polymerization method, functional polymers can be synthesized in situ on the living cell surface.

A thermo-responsive conjugated polymer, PFBT-gPA is synthesized by grafting the poly(N-isopropylacrylamide) (PNIPAAm) to the side chains of a conjugated polyfluorene derivative through atom transfer radical polymerization (ATRP). PFBT-gPA undergoes a reversible phase transition in water below and above the lower critical solution temperature (LCST) and the process is studied by differential scanning calorimetry (DSC) analysis and UV/vis absorption spectra. PFBT-gPA shows a good photostability under UV light irradiation especially above the LCST. Moreover, the photosensitizing performance of PFBT-gPA could be tuned simply by changing temperature. The unique properties of PFBT-gPA promise its potential applications in sensing and photodynamic therapy.

Owing to the misuse of antibiotics and slow development of new drugs, antibiotic-resistant pathogens have become a serious threat to human health. With the aim of developing new antimicrobial agents, we designed and synthesized a new conjugated polymer (PFPhim), which possesses an imidazolium containing backbone. The cationic backbone enables it to strongly interact with bacterial membrane leading to an antimicrobial ability that is more potent than that of a conjugated polymer containing a neutral backbone. PFPhim also displays strong photodynamic antimicrobial activity.

Carriers that can afford tunable physical and structural changes are envisioned to address critical issues in controlled drug delivery applications. Herein, photo-responsive conjugated polymer nanoparticles (CPNs) functionalized with donor-acceptor Stenhouse adduct (DASA) and folic acid units for controlled drug delivery and imaging are reported. Upon visible-light (λ=550 nm) irradiation, CPNs simultaneously undergo structure, color, and polarity changes that release encapsulated drugs into the cells. The backbone of CPNs favors FRET to DASA units boosting their fluorescence. Notably, drug-loaded CPNs exhibit excellent biocompatibility in the dark, indicating perfect control of the light trigger over drug release. Delivery of both hydrophilic and hydrophobic drugs with good loading efficiency was demonstrated. This strategy enables remotely controlled drug delivery with visible-light irradiation, which sets an example for designing delivery vehicles for non-invasive therapeutics.

To take advantage of the excellent optical properties of conjugated polymers (CPs) or conjugated oligomers (COs) for biological applications, there is still a requirement to find new ways to deliver these conjugated molecular materials into cells in a facile, controllable, and noninvasive manner. Herein, a photoactive oligo( p-phenylenevinylene) (OPV) derivative was covalently attached with phospholipid units (OPV-lipid) to enhance its dispersion in water and facilitate its internalization by cells. OPV-lipid could be delivered into either the cell membrane or cytoplasm controllably through the assistance of liposomes with different formulas. It could also act as a fluorescent probe for cell imaging and visualization of the delivery process. This work shows a good potential for delivering functional conjugated molecular materials into cells in a controllable way.

The emergence of drug-resistant bacterial strains makes antimicrobial treatment a big challenge. Thus, more novel and effective antimicrobial agents and treatments are urgently desired. Herein, we developed a facile and rapid photothermal antimicrobial nanoplatform based on near-infrared (NIR)-active and photothermal-responsive conjugated polymer nanoparticles (CPNs) functionalized with cell-penetrating peptide (CPNs-Tat). With a positively charged Tat peptide, CPNs-Tat could enhance the interaction with bacteria cells with the formation of CPNs-Tat/bacteria aggregation. Under NIR irradiation, CPNs-Tat could convert the light into heat efficiently and produce local hyperthermia to kill bacteria within a few minutes. This photothermal-responsive strategy offers a rapid and effective modality for combating bacterial infections.

A conjugated polymer-based supramolecular system is designed for discrimination of virus and microbes. The supramolecular system is composed of cationic polythiophene derivative (PT) and barrel-shaped macrocyclic molecular cucurbit[7]uril (CB[7]). Because PT and PT/CB[7] complexes possess different interaction manners toward virus and microbes, the rapid and simple discrimination of virus and microbes was realized through polymer fluorescence intensity change assisting with standard linear discriminant analysis (LDA). The supramolecular strategy would expand the idea of designing biological probes and further promote the extensive application of conjugated polymer materials in biosensor field.

In this work, a new photoelectrochemical (PEC) cytosensor was constructed by using cationic polyfluorene derivative, poly(9,9-bis(6'-(N,N,N,-trimethylammonium)hexyl)fluorene-co-alt-1,4-phenylene)bromide (PFP) as the photoelectric-responsive material for sensitive cell detection. Positive-charged PFP with high photoelectric conversion efficiency can generate robust photocurrent under light illumination. In the PEC cytosensor, 3-phosphonopropionic acid was linked to the indium tin oxide electrode, followed by modification with antiepithelial-cell-adhesion-molecule (EpCAM) antibody via amide condensation reaction. Thus, target SKBR-3 cells with overexpressed EpCAM antigen could be captured onto the electrode via the specific antibody-antigen interactions. Upon adding cationic PFP, a favorable electrostatic interaction between cationic PFP and negatively charged cell membrane led to a turn-on detection signal for target SKBR-3 cells. This new cytosensor not only exhibits good sensitivity because of the good photoelectric performance of conjugated polymers, but also offers decent selectivity to target cells by taking advantage of the specific antibody-antigen recognition.

In recent years, conjugated polymers (CPs) characterized with excellent optical properties and versatile chemical structures have become popular species for biological sensing and imaging. Many creative strategies have been proposed to furnish CPs with distinguished properties or integrate CPs with other functional moieties to form multifunctional materials, which have been widely applied in different biological conditions, ranging from in vitro to in vivo experiments. This review provides a brief introduction to recent strategies for constructing these CP-based materials for biological sensing and imaging applications, where the design strategies of the two basic components (backbones and side chains) of CPs are firstly highlighted, followed by the construction of CP-based composites including nanoparticle strategies and hybridization strategies. The challenges and opportunities in this field are also discussed in this review.

Unraveling the transformation of coagulants and their interaction with contaminants at the micro-level is vital to advancing our understanding of the coagulation mechanism. To the best of our knowledge, the coagulation effectiveness of [AlO4Al12(OH)24(H2O)12]7+ (Al13), regarded as the dominant species in polyaluminum chloride (PACl), is highly related to its aggregation characteristic, but the detailed process of Al13 aggregation in coagulation time scale was not well studies. Here we systematically studied the deprotonation and aggregation processes of Al13 by alkaline titration to simulate the reaction in coagulation case. By reacting with OH−, Al13 can continuously lose protons regardless of pH until its positive charge was well neutralized. The initial Al13 aggregates (Al13agg) appeared at B of 2.70 and large Al13agg was generated by coalescence of small initial Al13agg. Most Al13 polycations kept their main structure unchanged during aggregation and part was decomposed into monomers or oligomers. Density functional theory (DFT) results reveal that Al13 becomes unstable after deprotonation, but the aggregation of Al13 bridged by Al monomers can stabilize the polycations. Al13 needs to be hydrolyzed before interacting with colloidal particles, but particles can promote the aggregation of Al13 by weakening the repulsion force between the polymers. Strong and compact flocs can be generated induced by in-situ aggregation of Al13 in neutral and alkaline conditions. This study can provide a deep understanding about the role of Al13agg in removing particles and instruct the development of new efficient coagulants against the various water qualities.

Conjugated polymers (CPs) are referred to a kind of fluorescent polymer materials with delocalized π-conjugated backbones. For the last decades, cationic CPs (CCPs) have been widely used in biosensor, imaging and biomedical fields due to their good photophysical properties and solubility in water medium resulting from side chain modification with ionized moieties. In this mini-review, we mainly introduced the applications of CCPs in detection and inactivation of pathogen with typical examples, and also briefly discussed the relevant mechanisms. We hold the expectation that this mini-review can offer researchers a general reference and inspire them to construct new systems with high performances of pathogen detection and antimicrobial activity.

Optical imaging, as an important molecular imaging modality, has emerged many attractions in studying the biological or molecular events both in cell level and living subject because of its high resolution and sensitivity, noninvasive manner and low cost. Herein, we bring novel insights into a water-soluble conjugated polyelectlyte by deeply studying its properties in cells. Poly(9, 9-bis (6'- N,N,N -trimethylammonium hexyl)fluorene phenylene) (PFP), a good biosensing material, was studied in this paper. The biocompatibility of PFP was investigated in different cells, and cell cycle analysis was carried out to explore the reasons of different biocompatibility of PFP to cells. After irradiation, fluorescence enhancement of blue emission and turn-on of long-wavelength emission of PFP in HepG2 cells was observed, which was first reported as far as we know. The differentiated biocompatibility of PFP and its particular imaging properties in cancer cells can help to guide the application of conjugated polymers in cells and provide a new dimension in designing sensitive and responsive imaging materials.

Polymers are mostly trapped in lysosomes when they enter cells and are then expelled, otherwise they were designed to be degradable to small molecules or to sabotage lysosomes. Therefore, they have reached the limit of the unique functionalities as a whole. Different from other escaping strategies, we introduced the polarity exchanging approach to rigid-backboned conjugated polymer for controlled penetrating through endosome or lysosome membranes. With the aid of pH-sensitive cleavage of water-soluble side chain, the rigid conjugated polymer turns highly hydrophobic after it is internalized into lysosomes and then accomplishes escaping. Thus, polarity exchange of CPs could become a new strategy for their application on chemotherapeutics.

Apart from the wide applications in the field of electronic and optoelectronic devices, conjugated molecules have been established as useful functional materials for biological applications. By introducing hydrophilic side chains to conjugated backbones, water-soluble conjugated polymers or oligomers (CPs or COs) inherit the attractive optical and electronic properties from conjugated molecules, while their water solubility ensures interaction with biological substrates such as biomacromolecules, microorganisms, and living cells for further biological applications. Benefiting from high brightness, large extinction coefficients, excellent photostability, low cytotoxicity, stability in bodily fluids, and versatile structural modifications, water-soluble conjugated polymers and oligomers have offered powerful alternatives in a variety of biological applications including biological and chemical sensors, fluorescence imaging, disease diagnostics, and therapy. This Account will focus on our recent advances in design, synthesis, and interdisciplinary biological applications of a series of new water-soluble CP and CO materials, starting with a brief introduction to water-soluble CPs and COs and various methods and strategies developed for the preparation of advanced water-soluble CPs and COs. Since their properties can be tuned by rational design and synthesis at the level of the conjugated repeat unit and versatile pendant groups, CPs and COs provide a diverse toolbox for satisfying interdisciplinary biological applications. The application of water-soluble CPs and COs in the past five years can be broadly categorized into four areas. Specifically, integrating the unique optoelectronic properties of water-soluble CPs and COs with self-assembly and supramolecular strategies, efficacy regulation of antibiotic and anticancer drugs has been achieved, meanwhile drug resistance could be overcome and drug resistant "superbacteria" can be inhibited. For applications regulating cellular functions and biological processes, we introduce CPs and COs with the ability to regulate intracellular oxidative stress, cell-cell communication, cellular proliferation, cell membrane permeability, and quorum sensing of bacteria cells. By covalent linkage of reactive groups upon CPs and COs, these molecules are endowed with abilities like disassembly of amyloid polypeptides, biased distribution in cells, selective imaging of organelles, and distinguished interactions with biomolecules. For photothermal therapy (PTT) applications, photothermal-responsive conjugated polymer materials have been utilized for remote control of gene expression in living cells and in vivo photothermal therapy of cancer. Beyond these applications, we have achieved new interdisciplinary applications of water-soluble CP and CO materials for biological optoelectronic devices including photosynthesis, photocatalysis, and bioenergy. Specific features or properties of water-soluble CPs and COs are leveraged to bring opportunities for each of these applications. These studies open a new frontier for development of new functional conjugated molecule materials and provide better understanding of their interactions with biological systems as well as structure/property relationships. Current limitations confronted by CPs and COs are raised, and developmental direction for the future is proposed.

A novel supramolecular system based on conjugated polymers was developed to realize specific targeting and imaging of organelles in living cells. The carboxyl group-modified polythiophene derivative (PT) forms a complex with six histidine equipped Tat peptide via Ni2+ ion chelation, hydrogen bonds and electrostatic interactions (PT/Ni2+/Tat-His6). The complex can reassemble with RFP-His10 due to the relatively high affinity of Ni2+ towards His10-tag compared to His6-tag. Thus, the PT/Ni2+/Tat-His6 complex could selectively label and image organelles expressing His10-tag in living cells with high stability.

Photothermal therapy (PTT) holds great promise for noninvasive cancer treatment. To fulfill this goal, highly effective and low-risk photothermal agents have been intensively explored. Here, we present a new PTT material based on conjugated polymer dots (Pdots) that exhibit strong near-infrared (NIR) absorption and high photostability. The Pdots result in a thermal response upon illumination with a NIR laser, leading to a high photothermal conversion efficiency of 65%. Thus, the photothermal ablation of cancer cells using the Pdots both in vitro and in vivo can be achieved, highlighting the potential of Pdots as a nanoplatform for clinical therapy. They also open up a new avenue to develop new photothermal therapeutic materials.

The detection of pathogens plays a crucial role in clinical applications. In recent years, conjugated polymers are favorable in chemical and biological detections due to their remarkable light harvesting and optical signal amplification characteristics. However, most of the conjugated polymers exhibit cytotoxicity due to their rigid and hydrophobic backbone. To circumvent these deficiencies, one promising strategy is to develop a non-conjugated polymer with fluorescence, low-toxic and water-soluble characteristics. In this paper, we describe the synthesis and characterization of a novel water-soluble non-conjugated polymer (P1) containing chromophores with groups of quaternary ammonium cations in the side-chains and non-conjugated linkers of oligo(ethylene glycol) (OEG), the capability of which would not only increase the flexibility and hydrophilicity of the main-chain, but also reduce nonspecific adsorption to proteins and cell surfaces of microbial pathogens. Thus, through the balance between pendent groups of quaternary ammonium cations and OEG linkers, self-luminous P1 molecules could realize visual optical discrimination and detection of three kinds of microbial pathogens rapidly and simply by using a fluorescence microscope.

Conjugated polymers (CPs) have gained increasing attention as an optical platform for sensitive detection of biomacromolecules and fluorescent imaging in cellular and animal level due to its excellent light-harvesting and light-amplifying properties. Over the past decades, in order to meet the needs of multi-color fluorescent detection and imaging, researchers have designed and developed a series of multicolor fluorescent systems based on the fluorescence resonance energy transfer properties of conjugated polymers (CPs-FRET). The advantages of these systems include high brightness, excellent photostability, and low cytotoxicity. Multicolor fluorescence encoded detection of target molecules and fluorescence imaging can be achieved using such systems under a single excitation wavelength. In this tutorial review, we describe the FRET mechanism of CPs and the preparation of CPs-FRET based multicolor fluorescent systems, provide a brief review of the recent research progress of such systems in biochemical detection and cell imaging, and discuss the current problems and future direction of such systems.

A new water-soluble conjugated poly(fluorene-co-phenylene) derivative (PFP-FB) modified with boronate-protected fluorescein (peroxyfluor-1) via PEG linker has been designed and synthesized. In the presence of H2O2, the peroxyfluor-1 group can transform into green fluorescent fluorescein by deprotecting the boronate protecting groups. In this case, upon selective excitation of PFP-FB backbone at 380 nm, efficient fluorescence resonance energy transfer (FRET) from PFP-FB backbone to fluorescein occurs, and accordingly, the fluorescence color of PFP-FB changes from blue to green. Furthermore, the emission color of PFP-FB and the FRET ratio change in a concentration-dependent manner. By taking advantage of PFP-FB, ratiometric detection of choline and acetylcholine (ACh) through cascade enzymatic reactions and further dynamic monitoring of the choline consumption process of cancer cells have been successfully realized. Thus, this new polymer probe promotes the development of enzymatic biosensors and provides a simpler and more effective way for detecting the chemical transmitter of living cells.

An optical nanoruler system based on a conjugated polyelectrolyte-silver nanoprism pair is developed for label-free protein detection by taking advantage of the metal-enhanced fluorescence effect of silver nanostructures. Antibody-antigen interactions induce a change in the metal-fluorophore distance, followed by the response of a fluorescent signal of the conjugated polyelectrolyte. The system is used to detect target antigens sensitively and selectively.

A conjugated polymer (PTDHP) was synthesized by modifying the side chain of cationic polythiophene (PT) with a dihydropyridine (DHP) group via a click reaction. PTDHP has a unique ROS self-scavenging ability through the oxidation of the DHP into a pyridine structure upon light irradiation. Thus, PTDHP achieves cell imaging with good photo-stability and low photo-cytotoxicity.

In this work, we developed a kind of novel nontoxic soft particle self-assembled by gemini surfactant (SDHC) and conjugated polymer (PMNT). The soft particle shows strong ability in incorporating into cell membrane, and alters the membrane permeability, especially under light irradiation. The anticancer activities of doxorubicin (DOX) were enhanced 6–9 times after cancer cells were treated with the soft particles under light irradiation. The cell viabilities of three kinds of cancer cells testify that this effect of the soft particles on chemotherapy is universal. This work provides a new strategy to enhance the anticancer activities of drugs.

Development of Raman-active materials with enhanced and distinctive Raman vibrations in the Raman-silent region (1800-2800 cm-1) is highly required for specific molecular imaging of living cells with high spatial resolution. Herein, water-soluble cationic conjugated polymers (CCPs), poly(phenylene ethynylene) (PPE) derivatives, are explored for use as alkyne-state-dependent Raman probes for living cell imaging due to synergetic-enhancement effect of alkyne vibrations in Raman-silent region compared to alkyne-containing small molecules. The enhanced alkyne signals result from the integration of alkyne groups into the rigid backbone and the delocalized π-conjugated structure. PPE-based conjugated polymer nanoparticles (CPNs) were also prepared as Raman-responsive nanomaterials for distinct imaging application. This work opens a new way into the development of conjugated polymer materials for enhanced Raman imaging.

Conjugated polymers have great potential applications in bioimaging. However, the aggregation of conjugated polymers driven by electrostatic and hydrophobic interactions in aqueous media results in the reduction of photoluminescence quantum efficiency. In present work we synthesized a carboxylate gemini surfactant [sodium 2,6-didodecyl-4-hydroxy-2,6-diaza-1,7-heptanedicarboxylate (SDHC)] to adjust the aggregation behaviors and fluorescence properties of conjugated polymers [anionic poly(2-methoxy-5-propyloxy sulfonate phenylene vinylene) (MPS-PPV) and cationic poly(3-alkoxy-4-methylthiophene) (PMNT)]. This gemini surfactant shows very low critical micellar concentration (CMC) in aqueous solution and forms vesicles above CMC. In neutral and acidic conditions, MPS-PPV combines with the SDHC vesicles mainly via hydrophobic interactions and forms the aggregates in which the photoluminescence quantum efficiency of MPS-PPV is highly enhanced from 0.1% to 27%. As to PMNT, the molecules are located in the bilayer of SDHC vesicles through both electrostatic and hydrophobic interactions, and this structure prevents the production and release of reactive oxygen species. Moreover, SDHC is nontoxic and can effectively decrease the dark- and photocytotoxicity of MPS-PPV and PMNT, laying a good foundation for their bioimaging application. The living cell imaging indicates that the surfactant/conjugated polymer aggregates can stain the MCF-7 cells with main location in the lysosome. This work provides insight into how to improve the fluorescence properties and bioimaging applications of conjugated polymers by surfactants.

In this work, we demonstrate that water-soluble conjugated polymers (PFP) have the ability to inhibit biofilm formation and eradicate mature established biofilm using reactive oxygen species (ROS) produced by PFP under white light irradiation. Upon addition of PFP to planktonic Staphylococcus aureus (S. aureus), electrostatic interactions bring cationic PFP to the surface of S. aureus, which possesses negative charges. As the amount of PFP coated on S. aureus becomes saturated, the interactions of bacteria to bacteria and bacteria to surface may be disrupted, resulting in reduced biofilm formation. After the biofilm matures, those PFP on the surface of the biofilm can generate ROS under white light irradiation, which has the ability to inactivate bacteria nearby. Once the biofilm is broken, PFP can penetrate throughthe biofilm and continuously generate ROS under irradiation, resulting in biofilm disruption. As a consequence, this makes conjugated polymers a very promising material for the disruption of biofilm in biomedical and industrial applications.

The outstanding optical properties and biocompatibility of fluorescent conjugated polymer nanoparticles (CPNs) make them favorable for bioimaging application. However, few CPNs could achieve stable cell membrane labeling due to cell endocytosis. In this work, conjugated polymer nanoparticles (PFPNP-PLE) encapsulated with PFP and PLGA-PEG-N3 in the matrix and functionalized with the small-molecule drug plerixafor (PLE) on the surface were prepared by a mini-emulsion method. PFPNP-PLE exhibits excellent photophysical properties, low cytotoxicity, and specific cytomembrane location, which makes it a potential cell membrane labeling reagent with blue fluorescence emission, an important component for multilabel/multicolor bioimaging.

Infections of antibiotic-resistant pathogens have caused a series of public health crises across the world. According to the latest published reports, an antibiotic switch has been recognized as a potential strategy to control antibacterial activity for combating this serious drug resistance. Thus, it is anticipated that more effective antibiotic switches should be obtained by further exploring the developed strategies. Here, we report an improved pretreatment strategy using a surfactant (Triton X-100) for constructing an effective supramolecular antibiotic switch based on a poly(fluorene-co-phenylene) derivative (PFP) and cucurbit[7]uril (CB[7]), which can regulate the aggregation state of polymers before the supramolecular self-assembly process occurs. Triton X-100 can regulate the aggregation states of conjugated polymers, which is used to successfully realize the reversible control of bactericidal activity of PFP in the dark and under white light irradiation by supramolecular assembly/disassembly between PFP and CB[7]. Specialized antibiotic switches are significantly important to fight pathogenic infections and solve the drug resistance crisis in the future.

Cationic poly(fluorene-co-phenylene) derivative (PFP-NMe3+) forms a supramolecular complex with cucurbit[7]uril (CB[7]), which could be reversibly disassembled by amantadine (AD) to release PFP-NMe3+ due to the formation of more stable CB[7]/AD complex. The cationic PFP-NMe3+ is an amphiphilic structure and could bind to negatively charged membrane of pathogen by multivalent interactions. Upon the formation of PFP-NMe3+/CB[7] complex, the CB[7] could bury the side-chain alkyl groups and decreases the hydrophobic interactions of PFP-NMe3+ on the surface of pathogens; thus, PFP-NMe3+ exhibits different interaction modes with pathogens before and after assembly with CB[7]. The PFP-NMe3+/CB[7] supramolecular complex could be explored as optical sensor for simple, rapid, and in situ detection and discrimination of multiple pathogens by taking advantage of optical signal changes of PFP-NMe3+/CB[7] complex before and after disassembly by AD on the pathogen surfaces. The new sensor can realize in situ detection a...

Multifunctional nanomaterials with simultaneous therapeutic and imaging functions explore new strategies for the treatment of various diseases. Conjugated polymers (CPs) are considered as novel candidates to serve as multifunctional delivery systems due to their high fluorescence quantum yield, good photostability, and low cytotoxicity. Highly sensitive sensing and imaging properties of CPs are well reviewed, while the applications of CPs as delivery systems are rarely covered. This feature article mainly focuses on CP-based multifunctional non-viral delivery systems for drug, protein, gene, and cell delivery. Promising directions for the further development of CP-based delivery systems are also discussed.

A dopamine-modified conjugated polymer PFPDA is synthesized and characterized. At low pH, dopamine exists in its hydroquinone form and lacks the ability to quench fluorescence. At high pH, the proportion of the quinone form of dopamine increases due to its autooxidation, and efficient intramolecular electron transfer from the polymer main chain to quinone occurs, resulting in the quenching of the fluorescence of PFPDA. Thus, PFPDA exhibits a fluorescence “turn-on” response at low pH. PFPDA possesses excellent photostability and exhibits no cytotoxicity, which makes it a good fluorescent material for pH sensing and cell imaging. A light-induced hydroxyl anion emitter, MGCB, is also used to change the pH of the solution and thus regulate the fluorescence of PFPDA via remote control under light irradiation. Because the cytoplasm becomes acidic when cell autophagy occurs, PFPDA can also be used for autophagy imaging of HeLa cells with good selectivity.

A new water-soluble conjugated polymer containing fluorene and boron-dipyrromethene repeat units in the backbones (PBF) that exhibits red emission was synthesized and characterized. Cationic PBF forms uniform nanoparticles with negatively charged disodium salt 3,3'-dithiodipropionic acid (SDPA) in aqueous solution through electrostatic interactions. The nanoparticles display absorption maximum at 550 nm and emission maximum at 590 nm. Upon photoexcitation with white light (400-800 nm) with 90 and 45 mW·cm(-2) for bacteria and cancer cells killing respectively, PBF nanoparticles can sensitize the oxygen molecule to readily produce reactive oxygen species (ROS) for rapidly killing neighboring bacteria and cancer cells. Furthermore, PBF nanoparticles concurrently provide optical imaging capability. PBF nanoparticles are therefore a promising multifunctional material for treating cancers and bacteria infections, while concurrently providing optical monitoring capabilities.

A novel technique was developed for preparing encoded multicolour microparticles based on the self-assembly of bacteria and conjugated polymer nanoparticles (CPNs) by a very simple and time-saving manner. These bacteria-CPNs microparticles show multicolor emissions by tuning FRET efficiencies among CPNs under single excitation wavelength and can be successfully applied for cell imaging and optical barcoding.

A series of water-soluble polyfluorene derivatives containing diketopyrrolopyrrole derivative units are synthesized and characterized. These copolymers, poly[9,9'-bis(6”-N,N,N-trimethyl ammonium) hexylfluorene-co-alt-2,5-bis (6”-N,N,N-trimethylammonium)hexylpyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione] (PFDPN), demonstrate intramolecular energy transfer from the fluorene units to the diketopyrrolopyrrole derivative units, and show red-shifted emissions in aqueous solution. The PFDPN polymers can combine with Cy5-labeled ssDNA by electrostatic interactions and efficiently amplify the fluorescence signal of red Cy5 dye through fluorescence resonance energy transfer. Moreover, based on DNA replacement method, this amplification system can be used to monitor the template-independent DNA elongation process catalyzed by terminal deoxynucleotidyl transferase.

A fluorescent film sensor was prepared by chemical modification of a polyfluorene derivative on a glass-plate surface. X-ray photoelectron spectroscopy and ellipsometry measurements demonstrate the covalent attachment of the polyfluorene derivative to the glass-plate surface. The sensor was used to detect Cu2+ ions in aqueous solution by a mechanism exploiting fluorescence quenching of conjugated polymers. Among the tested metal ions, the film sensor presents good selectivity towards Cu2+ ions. Further experiments show that the sensing process is reversible. Moreover, sensory microarrays based on conjugated polymers targeting Cu2+ ions are constructed, which display similar sensing performance to that of the film sensor. The structural motif in which conjugated polymers are covalently confined to a solid substrate surface offers several attractive advantages for sensing applications. First, in comparison with film sensors in which small fluorescent molecules are employed as sensing elements, the sensitivity of our new film sensor is enhanced due to the signal-amplifying effect of the conjugated polymers. Second, the film sensors or microarrays can be used in aqueous environments, which is crucial for their potential use in a wide range of real-world systems. Since the sensing process is reversible, the sensing materials can be reused. Third, unlike physically coated polymer chains, the covalent attachment of the grafted chains onto a material surface precludes desorption and imparts long-term stability of the polymer chains.

Rapid and sensitive methods to detect proteins and protein denaturation have become increasingly needful in the field of proteomics, medical diagnostics, and biology. In this paper, we have reported the synthesis of a new cationic water-soluble conjugated polymer that contains fluorene and diene moieties in the backbone (PFDE) for protein identification by sensing an array of PFDE solutions in different ionic strengths using the linear discriminant analysis technique (LDA). The PFDE can form complexes with proteins by electrostatic and/or hydrophobic interactions and exhibits different fluorescence response. Three main factors contribute to the fluorescence response of PFDE, namely, the net charge density on the protein surface, the hydrophobic nature of the protein, and the metalloprotein characteristics. The denaturation of proteins can also be detected using PFDE as a fluorescent probe. The interactions between PFDE and proteins were also studied by dynamic light scattering (DLS) and isothermal titration microcalorimetry (ITC) techniques. In contrast to other methods based on conjugated polymers, the synthesis of a series of quencher or dye-labeled acceptors or protein substrates has been avoided in our method, which significantly reduces the cost and the synthetic complexity. Our method provides promising applications on protein identification and denaturation detection in a simple, fast, and label-free manner based on non-specific interaction-induced perturbation of PFDE fluorescence response.

We prepared a new conjugated polymer nanoparticle with the size of about 50 nm that is prepared by electrostatic assembly of cationic conjugated polymer PFO and anionic poly(l-glutamic acid) conjugated with anticancer drug doxorubicin (PFO/PG-Dox). The PFO exhibits good fluorescence quantum yield, photostability, and little cytotoxicity to meet the essential requests for cell imaging. In PFO/PG-Dox nanoparticles, the fluorescence of PFO is highly quenched by Dox by electron transfer mechanism, and thus the PFO is in the fluorescence "turn-off' state. After PFO/PG-Dox nanoparticles are exposed to carboxypeptidase or are taken up by cancer cells, the poly(l-glutamic acid) is hydrolysed to release the Dox, inducing the activation of PFO fluorescence to "turn-on" state. This multifunctional nanoparticle system can deliver Dox to targeted cancer cells and monitor the Dox release based on fluorescence "turn-on" signal of PFO, which concurrently images the cancer cells. The present work opens the door for new functional studies of conjugated polymer in simultaneous imaging and disease therapeutics.