Cationic conjugated polymer/fluoresceinamine-hyaluronan complex for sensitive fluorescence detection of CD44 and tumor-targeted cell imaging

Enzyme-Responsive Micelles with High Drug-Loading Capacity for Antitumor Therapy

To overcome the poor targeting of conventional chemotherapeutic drugs and the defects of low drug-loading capacity of conventional drug delivery systems, novel drug delivery systems with high drug-loading capacity are developed. Herein, the high drug-loaded mPEG79-GFLGDDD-DOX copolymer is first synthesized via an amide reaction, which can bond multiplex DOX. After PEGylation, the drug can resist the adsorption of proteins in the plasma in blood circulation, avoid being rapidly cleared out of the body, and prolong the circulation time of the drug in the blood, which is conducive to the enrichment of micelles in tumor tissues through the EPR effect. In tumor tissues, the peptide Glycine- Phenylalanine- Leucine- Glycine (GFLG) is recognized and sheared by overexpressed cathepsin B, which stripped the outer layer of methoxy polyethylene glycol (mPEG) and made it more readily available for uptake by tumor cells. After entering the tumor cells, the bonded DOX and the physically encapsulated DOX in the micelles played a synergistic role, realizing the killing of tumor cells, thus effectively enhancing the therapeutic effect on tumors. The findings in this work suggest that a high drug-loading drug delivery system has great potential in the clinical treatment of tumors.

Self-powered biosensing platform for Highly sensitive detection of soluble CD44 protein

In this study, a self-powered biosensor based on an enzymatic biofuel cell was proposed for the first time for the ultrasensitive detection of soluble CD44 protein. The as-prepared biosensor was composed of the co-exist aptamer and glucose oxidase bioanode and bilirubin oxidase modified biocathode. Initially, the electron transfer from bioanode to biocathode was hindered due to the presence of the aptamer with high insulation, generating a low open-circuit voltage (EOCV). Once the target CD44 protein was present, it was recognized and captured by the aptamer at the bioanode, thus the interaction between the target CD44 protein and the immobilized aptamer caused the structural change at the surface of the electrode, which facilitated the transfer of electrons. The EOCV showed a good linear relationship with the logarithm of the CD44 protein concentrations in the range of 0.5-1000 ng mL-1 and the detection limit was 0.052 ng mL-1 (S/N = 3). The sensing platform showed excellent anti-interference performance and outstanding stability that maintained over 97% of original EOCV after 15 days. In addition, the relative standard deviation (1.40-1.96%) and recovery (100.23-101.31%) obtained from detecting CD44 protein in real-life blood samples without special pre-treatment indicated that the constructed biosensor had great potential for early cancer diagnosis.

Literature Review on Conjugated Polymers as Light-Sensitive Materials for Photovoltaic and Light-Emitting Devices in Photonic Biomaterial Applications

Due to their extended p-orbital delocalization, conjugated polymers absorb light in the range of visible-NIR frequencies. We attempt to exploit this property to create materials that compete with inorganic semiconductors in photovoltaic and light-emitting materials. Beyond competing for applications in photonic devices, organic conjugated compounds, polymers, and small molecules have also been extended to biomedical applications like phototherapy and biodetection. Recent research on conjugated polymers has focused on bioapplications based on the absorbed light energy conversions in electric impulses, chemical energy, heat, and light emission. In this review, we describe the working principles of those photonic devices that have been applied and researched in the field of biomaterials.

A short review article on conjugated polymers

This article provides a brief review of conjugated polymers and the various typical polymerization reactions exploited by the community to synthesise different conjugated polyelectrolytes with varied conjugated backbone systems. We further discuss with detailed emphasises the mechanism involved such as photo-induced electron transfer, resonance energy transfer, and intra-molecular charge transfer in the detection or sensing of various analytes. Owing to their excellent photo-physical properties, facile synthesis, ease of functionalization, good biocompatibility, optical stability, high quantum yield, and strong fluorescence emission. Conjugated polymers have been explored for wide applications such as chemical and biological sensors, drug delivery and drug screening, cancer therapeutics and imaging. As such we believe it will be a timely review article for the community.

Electrochemically Exfoliated Graphene Quantum Dots Based Biosensor for CD44 Breast Cancer Biomarker

An innovative electrochemical biosensor based on graphene quantum dots (GQDs) is developed for a simple, rapid, and highly sensitive primary diagnosis of the breast cancer biomarker cluster of differentiation-44 (CD44) antigen. Herein, electrochemical exfoliation of waste dry batteries provides facile, eco-friendly, and cost-effective synthesis of GQDs. Transmission electron microscopy (TEM) analysis reveals that GQDs exhibit spherical shapes with an average diameter of 4.75 nm. Further, electrochemical analysis through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) reveals that the electrochemical properties of GQDs are suitable for biosensing applications. Subsequently, GQDs have a large electroactive surface area that has been utilized for the immobilization of CD44 antibodies to fabricate the electrochemical biosensor. The electroanalytical performance of GQDs for CD44 biosensing capabilities is studied by differential pulse voltammetry (DPV). The developed electrochemical biosensor has high sensitivity with the lowest detection limit (LOD) of 2.11 fg/mL in the linear range of 0.1 pg/mL to 100.0 ng/mL in phosphate buffer saline (PBS). Further, the linear response of the electrochemical biosensor for CD44 antigen concentration is in the range of 1.0 pg/mL to 100.0 ng/mL with a LOD of 2.71 fg/mL in spiked serum samples. The outcomes suggest that the synthesized GQDs demonstrate promising attributes to be utilized as a viable nanomaterial in biosensing applications.

An Electrochemical Immunosensor Based on Gold-Graphene Oxide Nanocomposites with Ionic Liquid for Detecting the Breast Cancer CD44 Biomarker

We develop a highly sensitive electrochemical immunosensor for the detection of a cluster of differentiation-44 (CD44) antigen, a breast cancer biomarker. The hybrid nanocomposite consists of graphene oxide, ionic liquid, and gold nanoparticles (GO-IL-AuNPs) immobilized on a glassy carbon electrode. GO favors the immobilization of antibodies because of the availability of oxygen functionalities. However, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM.BF₄) and AuNPs facilitate electron transfer and increase the effective surface area, which enhances the performance of the immunosensor. Furthermore, UV-visible, fourier transform infrared and Raman spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, voltammetry, and electrochemical impedance spectroscopy characterization techniques have been employed to investigate the structural and chemical properties of the nanomaterials. The quantitative detection of CD44 antigen has been accomplished via differential pulse voltammetry and EIS detection techniques. It has been quantified that the proposed immunosensor offers excellent detection ability in both phosphate-buffered saline (PBS) and serum samples. Under optimum conditions, the linear detection range of the immunosensor for CD44 antigen is 5.0 fg mL^-1 to 50.0 μg mL^-1 and the limit of detection is 2.0 and 1.90 fg mL^-1 as observed via DPV and EIS, respectively, in PBS. Additionally, the immunosensor has high sensitivity and specificity and can be successfully applied for the detection of CD44 antigen in clinical samples.

Recent progress in the early detection of cancer based on CD44 biomarker; nano-biosensing approaches

CD44 is a cell matrix adhesion molecule overexpressed on the cell surfaces of the major cancers. CD44 as a cancer-related biomarker has an essential role in the invasion and metastasis of cancer. The detection and quantification of CD44 can provide essential information useful for clinical cancer diagnosis. In this regard, biosensors with sensitive and specific properties, give prominence to the development of CD44 detection platforms. To date, various aptamer-based sensitive-enhancers together with nanoparticles (NPs) have been combined into the biosensors systems to provide an innovative biosensing method (aptasensors/nano-aptasensors) with substantially improved detection limit. This review article discusses the recent advances in the field of biosensors, nanobiosensors, and aptasensors for the quantitative determination of CD44 and the detection of CD44-expressing cancer cells.

Conjugated polymer nanoparticles and their nanohybrids as smart photoluminescent and photoresponsive material for biosensing, imaging, and theranostics

The emergence of conjugated polymers (CPs) has provided a pathway to attain smart multifunctional conjugated polymer nanoparticles (CPNs) with enhanced properties and diverse applications. CPNs based on π-extended CPs exhibit high fluorescence brightness, low cytotoxicity, excellent photostability, reactive oxygen species (ROS) generation ability, high photothermal conversion efficiency (PCE), etc. which endorse them as an excellent theranostic tool. Furthermore, the unique light-harvesting and energy transfer properties of CPNs enables their transformation into smart functional nanohybrids with augmented performance. Owing to such numerous features, simple preparation method and an easy separation process, the CPNs and their hybrids have been constantly rising as a frontrunner in the domain of medicine and much work has been done in the respective research area. This review summarizes the recent progress that has been made in the field of CPNs for biological and biomedical applications with special emphasis on biosensing, imaging, and theranostics. Following an introduction into the field, a first large section provides overview of the conventional as well as recently established synthetic methods for various types of CPNs. Then, the CPNs-based fluorometric assays for biomolecules based on different detection strategies have been described. Later on, examples of CPNs-based probes for imaging, both in vitro and in vivo using cancer cells and animal models have been explored. The next section highlighted the vital theranostic applications of CPNs and corresponding nanohybrids, mainly via imaging-guided photodynamic therapy (PDT), photothermal therapy (PTT) and drug delivery. The last section summarizes the current challenges and gives an outlook on the potential future trends on CPNs as advanced healthcare material.

Photothermal-Chemotherapy Enhancing Tumor Immunotherapy by Multifunctional Metal-Organic Framework Based Drug Delivery System

Immunotherapy holds great promise for patients undergoing tumor treatment. However, the clinical effect of immunotherapy is limited because of tumor immunogenicity and its immunosuppressive microenvironment. Herein, the metal-organic framework (MIL-100) loaded with chemotherapeutic agent mitoxantrone (MTO) was combined with photothermal-chemotherapy for enhancing immunogenic cell death. MIL-100 loaded with MTO and hyaluronic acid as nanoparticles (MMH NPs) yielded an NP with two therapeutic properties (photothermal and chemotherapy) with dual imaging modes (photoacoustic and thermal). When MMH NPs were coinjected with an anti-OX40 antibody in colorectal cancer, the highest antitumor efficacy and a robust immune effect were achieved. This work provides a novel combined therapeutic strategy, which will hold great promise in future tumor therapy.

Label-Free Antifouling Photoelectrochemical Sensing Strategy for Detecting Breast Tumor Cells Based on Ligand-Receptor Interactions

Biomarker expression both on the cell surface and in serum is directly related to the pathological process of tumor. Based on the interaction between the ligand and the protein receptor, a label-free photoelectrochemical (PEC) biosensing interface with good antifouling ability was proposed for tumor cell detection. TiO₂ nanotube (NT) arrays were used as the substrate to enhance the ability of the biosensor to capture the target. Mercapto-terminated 8-arm poly(ethylene glycol) was introduced onto the electrode surface by the deposition of Au nanoparticles on TiO₂ NTs, creating an antifouling molecular layer. The recognition ligand hyaluronic acid (HA) was functionalized by dopamine and introduced onto the sensing surface based on the unique chelating interaction between the catechol group and the titanium atom. Benefitting from the specific recognition of HA with CD44 and the 3D porous structures of NTs, the constructed PEC biosensor showed excellent abilities toward the detection of MDA-MB-231 breast tumor cells and the soluble form of CD44. The ligand-receptor PEC sensing strategy has promising potential for the detection of tumor cells and protein biomarkers.

Supramolecular Prodrug Nanovectors for Active Tumor Targeting and Combination Immunotherapy of Colorectal Cancer

Immunotherapy aiming to harness the exquisite power of the immune system has emerged as a crucial part of clinical cancer management. However, only a subset of cancer patients responds to current immunotherapy because of low immunogenicity of the tumor cells and immunosuppressive tumor microenvironment. Herein, host-guest prodrug nanovectors are reported for active tumor targeting and combating immune tolerance in tumors. The prodrug nanovectors are designed by integrating hyaluronic acid (HA) and reduction-labile heterodimer of Pheophorbide A (PPa) and NLG919 into the supramolecular nanocomplexes, where PPa and NLG919 act as a photosensitizer and potent inhibitor of indoleamine 2,3-dioxygenase 1 (IDO-1), respectively. Meanwhile, HA is employed to achieve active tumor targeting by recognizing CD44 overexpressed on the surface of tumor cell membranes. Near infrared (NIR) laser irradiation triggers the release of reactive oxygen species to provoke antitumor immunogenicity and intratumoral infiltration of cytotoxic T lymphocytes (CTLs). Meanwhile, the immunosuppressive tumor microenvironment (ITM) is reversed by NLG919-mediated IDO-1 inhibition. Combination of photodynamic immunotherapy and IDO-1 blockade efficiently eradicates CT26 colorectal tumors in the immunocompetent mice. The host-guest nanoplatform capable of eliciting effective antitumor immunity by inactivating inhibitory immune response can be applied to other immune modulators for improved cancer immunotherapy.

Photoelectrochemical Biosensor for Sensitive Detection of Soluble CD44 Based on the Facile Construction of a Poly(ethylene glycol)/Hyaluronic Acid Hybrid Antifouling Interface

The serum level of soluble CD44 is directly associated with several clinicopathological parameters of malignant diseases. There is a great need for the development of an easy and cost-effective detection method for soluble CD44 for both the diagnosis and the treatment of cancers. In this work, a simple photoelectrochemical (PEC) method for the sensitive detection of serum-soluble CD44 is proposed based on the construction of a hybrid antifouling coating on the TiO₂ substrate. Hyaluronic acid (HA) and poly(ethylene glycol) (PEG) are co-immobilized using a biomimetic one-step surface functionalization approach. The immobilized HA shows strong recognition abilities toward soluble CD44, and the synergistic antifouling effect achieved by the combination of PEG and HA improves the sensing specificity. Based on the inhibitory effect of CD44 recognition on the PEC signal of the TiO₂ substrate, a PEC biosensor is developed with a wide response range and a low detection limit. The development of antibody-free biosensors may promote the application of soluble CD44 as a biomarker for the diagnosis and treatment of malignant diseases.

A Novel Multimodal NIR-II Nanoprobe for the Detection of Metastatic Lymph Nodes and Targeting Chemo-Photothermal Therapy in Oral Squamous Cell Carcinoma

Current surgical treatment for oral squamous cell carcinoma (OSCC) must be as precise as possible to fully resect tumors and preserve functional tissues. Thus, it is urgent to develop efficient fluorescent probes to clearly identify tumor delineation, as well as metastatic lymph nodes. Chemo-photothermal therapy combination attracted a growing attention to increase anti-tumor effect in various types of cancer, including OSCC. In the present study, we designed a multimodal NIR-II probe that involves combining photothermal therapy with chemotherapy, imaging OSCC tumors and detecting metastatic lymph nodes. Methods: In this study, we synthesized a novel near infrared (NIR)-II probe named TQTPA [4,4'-((6,7-bis(4-(hexyloxy)phenyl)-[1,2,5]thiadiazolo [3,4-g]quinoxaline-4,9-diyl)bis(thiophene-5,2-diyl))bis(N,N-diphenylaniline)] via the Suzuki reaction and prepared multimodal nanoparticles (NPs) loading TQTPA and cis-dichlorodiammine platinum (CDDP) (HT@CDDP) by hyaluronic acid. The characteristics of the NPs, including their photothermal and imaging capabilities were investigated in vitro and in vivo. Their anti-tumor efficacy was evaluated using orthotopic, tongue tumor-bearing, nude mice. Results: The NPs possessed good stability and water solubility and were pH/hyaluronidase sensitive. The good tissue penetration quality and active targeting ability enabled the NPs to draw the outline of orthotopic tongue tumors and metastatic lymph nodes as small as 1 mm in nude mice by IR-808 under NIR exposure. In vitro and in vivo experiments validated the biocompatibility and low systematic toxicity of the NPs. At the same time, the NPs acted as multimodal therapy agents, combining photothermal therapy with chemotherapy. Conclusion: With a good imaging capability and anti-tumor efficacy, our NPs successfully outlined orthotopic tongue tumors and metastatic lymph nodes as well as enabled chemo-photothermal therapy combination. Our study established a solid foundation for the application of new clinical diagnosis and treatment patterns in the future.

Redox-responsive hyaluronic acid-functionalized graphene oxide nanosheets for targeted delivery of water-insoluble cancer drugs

Background

Gefitinib (Gef), an important epidermal growth factor receptor (EGFR), is used to treat lung cancer, but low water solubility and poor bioavailability severely limit its application in cancer therapy.

Methods

In this study, nanographene oxide (NGO) was decorated with hyaluronic acid (HA) by a linker cystamine dihydrochloride containing disulfide bonds (-SS-), followed by the incorporation of gefitinib, thus, constructing a HA-functionalized GO-based gefitinib delivery system (NGO-SS-HA-Gef). Subsequently, studies of biological experiments in vitro and in vivo were performed to investigate the therapeutic effect of the system in lung cancer.

Results

The HA-grafted GO nanosheets possessed enhanced physiological stability, admirable biocompatibility, and no obvious side effects in mice and could act as a nanocarrier for the delivery of gefitinib to tumor. Cellular uptake and intracellular cargo release assays showed that the uptake of NGO-SS-HA by A549 cells was facilitated via CD44 receptor-mediated endocytosis, and that more drug was released from NGO-SS-HA in the presence of GSH than in the absence of GSH. The target-specific binding of NGO-SS-HA to cancer cells with redox-responsive cargo release significantly enhanced the abilities of gefitinib-loaded GO nanosheets to induce cell apoptosis, suppress cell proliferation, and inhibit tumor growth in lung cancer cell-bearing mice.

Conclusion

The results demonstrated the potential utility of NGO-SS-HA-Gef for therapeutic applications in the treatment of lung cancer.

A core/shell stabilized polysaccharide-based nanoparticle with intracellular environment-sensitive drug delivery for breast cancer therapy

In this work, we developed a novel core/shell chitosan (Cs)/hyaluronan (HA)-based hybrid nanoparticle, i.e. SNX@Cs-SNX/cHA, with good stability in the bloodstream and intracellular environment-sensitive drug delivery for breast cancer therapy.

A CD44-biosensor for evaluating metastatic potential of breast cancer cells based on quartz crystal microbalance

A sensitive CD44-biosensor based on quartz crystal microbalance (QCM) was proposed for evaluating metastatic potential of breast cancer cells by using hyaluronan (HA) functionalized substrate film, polydopamine and polyethyleneimine composite film, for the purpose of capturing CD44-positive cancer cells through specific binding of HA to CD44. Two differently CD44-expressed breast cancer cell lines (MDA-MB-231 cells and MCF-7 cells) were put to use as targets for quantitative analysis as well as evaluation of metastatic potential of the cells. The limit of detection for MDA-MB-231 (M231) cells and MCF-7 cells were 300 and 1,000cellsmL^-1, respectively. The expression level of CD44 on M231 cells exhibited two times higher than that of MCF-7 cells, indicating of a higher metastatic potential. Moreover, poly-L-lysine modified QCM sensor was applied to monitor the stiffness of breast cancer cells that can reflect metastatic potential of cells. The results revealed that the MCF-7 cells were stiffer than M231 cells, implying that the M231 cells possessed higher metastatic potential. The proposed protocol is simple and rapid to evaluate the metastatic potential of cancer cells, in addition to offering a promising diagnostic tool for metastatic cancer.

Coadministration of Oligomeric Hyaluronic Acid-Modified Liposomes with Tumor-Penetrating Peptide-iRGD Enhances the Antitumor Efficacy of Doxorubicin against Melanoma

A safe and efficient tumor-targeting strategy based on oligomeric hyaluronic acid (HA) modification and coadministration of tumor-penetrating peptide-iRGD was successfully developed. In this study, common liposomes (cLip) were modified by oligomeric HA to obtain HA-Lip. After injection into rats, HA-Lip showed good stealth in the bloodstream and lower liver distribution compared with cLip. Moreover, our HA-Lip could be internalized into B16F10 cells (CD44-overexpressing tumor cells) through HA-CD44 interaction. After systemic administration to B16F10 melanoma-bearing mice, HA-Lip showed an increased distribution in tumor due to the prolonged blood circulation time and the enhanced penetration and retention effect. When coadministered with iRGD, the tumor penetration of HA-Lip was significantly enhanced, which could promote HA-Lip internalization by tumors cells located in deep tumor regions through receptor-mediated endocytosis. Furthermore, doxorubicin (DOX)-loaded HA-Lip coadministering with iRGD showed much better antitumor effect compared to DOX-loaded cLip and DOX-loaded cLip in combination with iRGD. In systemic toxicity test, DOX-loaded HA-Lip could significantly decrease the cardiotoxicity and myelosuppression of DOX. Taken together, our results demonstrated that coadministration of oligomeric HA-modified liposomes with iRGD could be a promising treatment strategy for targeted therapy of melanoma.

Self-assembled nanoparticles based on a cationic conjugated polymer/hyaluronan–cisplatin complex as a multifunctional platform for simultaneous tumor-targeting cell imaging and drug delivery

A multifunctional nanoparticle system based on a cationic conjugated polymer/hyaluronan–cisplatin complex for tumor-targeting cell imaging and drug delivery.

Ratiometric Array of Conjugated Polymers-Fluorescent Protein Provides a Robust Mammalian Cell Sensor

Supramolecular complexes of a family of positively charged conjugated polymers (CPs) and green fluorescent protein (GFP) create a fluorescence resonance energy transfer (FRET)-based ratiometric biosensor array. Selective multivalent interactions of the CPs with mammalian cell surfaces caused differential change in FRET signals, providing a fingerprint signature for each cell type. The resulting fluorescence signatures allowed the identification of 16 different cell types and discrimination between healthy, cancerous, and metastatic cells, with the same genetic background. While the CP-GFP sensor array completely differentiated between the cell types, only partial classification was achieved for the CPs alone, validating the effectiveness of the ratiometric sensor. The utility of the biosensor was further demonstrated in the detection of blinded unknown samples, where 121 of 128 samples were correctly identified. Notably, this selectivity-based sensor stratified diverse cell types in minutes, using only 2000 cells, without requiring specific biomarkers or cell labeling.

Sensitive Conjugated-Polymer-Based Fluorescent ATP Probes and Their Application in Cell Imaging

Three cationic conjugated polyelectrolytes (CPEs) with a common poly(p-phenylene ethynylene terthiophene) backbone and side chains of different lengths, named as PPET3-N1, PPET3-N2, and PPET3-N3, were designed and synthesized. The UV-vis absorption and fluorescence spectra of the polymers vary strongly with solvent composition, suggesting that the polymers are strongly aggregated in H2O. In addition, the spectroscopic properties of the polymers are affected by small-molecule ATP, characterized by significant fluorescence intensity decreases and red shifts of their absorption bands. Further application of these polymers in cell imaging was studied by confocal fluorescence microscopy, which demonstrated that all of the polymers were localized on the cell membrane and partially inside of cells and that the staining effect gradually increased with the length of the polymer side chains. On the basis of the low cytotoxicity and efficient quenching of PPET3-N2 by ATP, the dose and time effects of ATP on PPET3-N2 imaging were studied, and the results indicated that this polymer might have potential in cell imaging for ATP semiquantification in vivo.

Cationic Conjugated Polymer/Hyaluronan-Doxorubicin Complex for Sensitive Fluorescence Detection of Hyaluronidase and Tumor-Targeting Drug Delivery and Imaging

Hyaluronidase (HAase) is becoming a new type of tumor marker since it has been demonstrated to be overexpressed in various kinds of cancer cells. In this study, we described a novel fluorescence method for sensitive, rapid, and convenient HAase detection and tumor-targeting drug delivery and imaging, using a probe prepared by electrostatic assembly of a cationic conjugated polymer (CCP) and anionic hyaluronan (HA) conjugated with the anticancer drug doxorubicin (Dox). The CCP we used was poly{[9,9-bis(6'-(N,N,N-diethylmethylammonium)hexyl)-2,7-fluorenylene ethynylene]-alt-co-[2,5-bis(3'-(N,N,N-diethylmethylammonium)-1'-oxapropyl)-1,4-phenylene]} tetraiodide (PFEP). HA is a natural mucopolysaccharide that can be hydrolyzed by HAase into fragments with low molecular weights. In the PFEP/HA-Dox complex, the fluorescence of PFEP was efficiently quenched due to electron transfer from PFEP to Dox. After the PFEP/HA-Dox complex was exposed to HAase or was taken up by cancer cells through the specific binding between HA and CD44 receptor, HA was degraded by HAase to release the Dox, leading to the recovery of PFEP fluorescence to the "turn-on" state. Moreover, the degree of fluorescence recovery was quantitatively correlated with the concentrations of HAase. Compared with many previously reported methods, our work did not require laborious multiple modifications of HA that may affect the activity of HAase. This point, combined with the excellent optoelectronic property of conjugated polymer, endowed this method with high sensitivity (detection limit: 0.075 U/mL), high specificity, and rapid response, making it applicable for reliable and routine detection of HAase. This fluorescent probe was successfully utilized to detect HAase levels in human urine samples; furthermore, it can also be employed as a multifunctional system by realizing tumor-targeting drug delivery and cell imaging simultaneously. The development of this fluorescence method showed promising potential for early tumor diagnosis and therapy based on HAase detection.

Polypeptide-b-Poly(Phenyl Isocyanide) Hybrid Rod-Rod Copolymers: One-Pot Synthesis, Self-Assembly, and Cell Imaging

Hybrid rod-rod diblock copolymers, poly(γ-benzyl L-glutamate)-poly(4-cyano-benzoic acid 2-isopropyl-5-methyl-cyclohexyl ester) (PBLG-PPI), with determined chirality are facilely synthesized through sequential copolymerization of γ-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) and phenyl isocyanide monomers bearing chiral menthyl pendants using a Ni(cod)(bpy) complex as the catalyst in one-pot. Circular dichroism and absorption spectra reveal that each block of the block copolymers possesses a stable helical conformation with controlled helicity in solution due to the induction of chiral pendants. The two diastereomeric polymers self-assemble into helical nanofibrils with opposite handedness due to the different chiral induction of the L- and D-menthyl pendants, confirmed by transmission electron microscopy (TEM). Deprotection of the benzyl groups of the PBLG segment affords biocompatible amphiphilic diblock copolymers, poly(L-glutamic acid)-poly(4-cyano-benzoic acid 2-isopropyl-5-methyl-cyclohexyl ester) (PLGA-PPI), that can self-assemble into well-defined micelles by cosolvent induced aggregation. Very interestingly, a chiral rhodamine chromophores RhB(D) can be selectively encapsulated into the chiral polymeric micelles, which is efficiently internalized into living cells when directly monitored with a confocal microscope. This contribution will be useful for developing novel rod-rod biocompatible hybrid block copolymers with a controlled helicity, and may also provide unique chiral materials for potential bio-medical applications.

ROS self-scavenging polythiophene materials for cell imaging

A conjugated polymer (PTDHP) was synthesized which has a unique ROS self-scavenging ability through the oxidation of DHP into a pyridine structure upon light irradiation. Thus, PTDHP achieves cell imaging with good photo-stability and low photo-cytotoxicity.

A green and facile method for the preparation of a pH-responsive alginate nanogel for subcellular delivery of doxorubicin

A one-pot preparation of a drug-loaded alginate nanogel was achieved upon the optimization of the concentration and their ratio of alginate, calcium ion and doxorubicin. The nanogel exhibited apparent pH-responsive release and subcellular delivery.