Hydrogen Bond Strength-Mediated Self-Assembly of Supramolecular Nanogels for Selective and Effective Cancer Treatment.

This study provides a significant contribution to the development of multiple hydrogen-bonded supramolecular nanocarrier systems by demonstrating that controlling the hydrogen bond strength within supramolecular polymers represents a crucial factor to tailor the drug delivery performance and enhance the effectiveness of cancer therapy. Herein, we successfully developed two kinds of poly(ethylene glycol)-based telechelic polymers Cy-PEG and UrCy-PEG having self-constituted double and quadruple hydrogen-bonding cytosine (Cy) and ureido-cytosine (UrCy) end-capped groups, respectively, which directly assemble into spherical nanogels with a number of interesting physical characteristics in aqueous solutions. The UrCy-PEG nanogels containing quadruple hydrogen-bonded UrCy dimers exhibited excellent long-term structural stability in a serum-containing biological medium, whereas the double hydrogen-bonded Cy moieties could not maintain the structural integrity of the Cy-PEG nanogels. More importantly, after the drug encapsulation process, a series of in vitro experiments clearly confirmed that drug-loaded UrCy-PEG nanogels induced selective apoptotic cell death in cancer cells without causing significant cytotoxicity to healthy cells, while drug-loaded Cy-PEG nanogels exerted nonselective cytotoxicity toward both cancer and normal cells, indicating that increasing the strength of hydrogen bonds in nanogels plays a key role in enhancing the selective cellular uptake and cytotoxicity of drugs and the subsequent induction of apoptosis in cancer cells.

CO2-Responsive Water-Soluble Conjugated Polymers for In Vitro and In Vivo Biological Imaging.

Water-soluble conjugated polymers (WCPs) composed of a hydrophobic polythiophene main chain with hydrophilic tertiary amine side-chains can directly self-assemble into sphere-like nano-objects in an aqueous solution due to phase separation between the hydrophilic and hydrophobic segments of the polymeric structure. Due to the presence of gas-responsive tertiary amine moieties in the spherical structure, the resulting polymers rapidly and reversibly tune their structural features, surface charge, and fluorescence performance in response to alternating carbon dioxide (CO2) and nitrogen (N2) bubbling, which leads to significantly enhanced fluorescence and surface charge switching properties and a stable cycle of on and off switching response. In vitro studies confirmed that the CO2-treated polymers exhibited extremely low cytotoxicity and enhanced cellular uptake ability in normal and tumor cells, and thus possess significantly improved fluorescence stability, distribution, and endocytic uptake efficiency within cellular organisms compared to the pristine polymer. More importantly, in vivo assays demonstrated that the CO2-treated polymers displayed excellent biocompatibility and high fluorescence enhancement in living zebrafish, whereas the fluorescence intensity and stability of zebrafish incubated with the pristine polymer decreased linearly over time. Thus, these CO2 and N2-responsive WCPs could potentially be applied as multifunctional fluorescent probes for in vivo biological imaging.

Self-Assembled pH-Responsive Polymeric Micelles for Highly Efficient, Noncytotoxic Delivery of Doxorubicin Chemotherapy To Inhibit Macrophage Activation: In Vitro Investigation.

Self-assembled pH-responsive polymeric micelles, a combination of hydrophilic poly(ethylene glycol) segments and hydrogen bonding interactions within a biocompatible polyurethane substrate, can spontaneously self-assemble into highly controlled, nanosized micelles in aqueous solution. These newly developed micelles exhibit excellent pH-responsive behavior and biocompatibility, highly controlled drug (doxorubicin; DOX) release behavior, and high drug encapsulation stability in different aqueous environments, making the micelles highly attractive potential candidates for safer, more effective drug delivery in applications such as cancer chemotherapy. In addition, in vitro cell studies revealed the drug-loaded micelles possessed excellent drug entrapment stability and low cytotoxicity toward macrophages under normal physiological conditions (pH 7.4, 37 °C). When the pH of the culture media was reduced to 6.0 to mimic the acidic tumor microenvironment, the drug-loaded micelles triggered rapid release of DOX within the cells, which induced potent antiproliferative and cytotoxic effects in vitro. Importantly, fluorescent imaging and flow cytometric analyses confirmed the DOX-loaded micelles were efficiently delivered into the cytoplasm of the cells via endocytosis and then subsequently gradually translocated into the nucleus. Therefore, these multifunctional micelles could serve as delivery vehicles for precise, effective, controlled drug release to prevent accumulation and activation of tumor-promoting tumor-associated macrophages in cancer tissues. Thus, this unique system may offer a potential route toward the practical realization of next-generation pH-responsive therapeutic delivery systems.

Binary-blend fibber-based capture assay of circulating tumor cells for clinical diagnosis of colorectal cancer.

BACKGROUND: In addition to conventional approaches, detecting and characterizing CTCs in patient blood allows for early diagnosis of cancer metastasis. METHODS: We blended poly(ethylene oxide) (PEO) into nylon-6 through electrospinning to generate a fibrous matbased circulating tumour cells (CTCs) assay. The contents of nylon-6 and PEO in the electrospun blend fibrous mats (EBFMs) were optimized to facilitate high cell-substrate affinity and low leukocyte adsorption. RESULTS: Compared with the IsoFlux System, a commercial instrument for CTC detection, the CTC assay of EBFMs exhibited lower false positive readings and high sensitivity and selectivity with preclinical specimens. Furthermore, we examined the clinical diagnosis accuracy of colorectal cancer, using the CTC assay and compared the results with those identified through pathological analyses of biopsies from colonoscopies. Our positive expressions of colorectal cancer through CTC detection completely matched those recognized through the pathological analyses for the individuals having stage II, III, and IV colorectal cancer. Nevertheless, two in four individuals having stage I colorectal cancer, recognized through pathological analysis of biopsies from colonoscopies, exhibited positive expression of CTCs. Ten individuals were identified through pathological analysis as having no colorectal tumours. Nevertheless, two of these ten individuals exhibited positive expression of CTCs. CONCLUSIONS: Thus, in this population, the low cost EBFMs exhibited considerable capture efficiency for the non-invasive diagnosis of colorectal cancer.

Fabrication of device with poly(N-isopropylacrylamide)-b-ssDNA copolymer brush for resistivity study.

In this study, we grafted bromo-terminated poly(N-isopropylacrylamide) (PNIPAAm) brushes onto thin gold films deposited on silicon, and then reacted with NaN3 to produce azido-terminated PNIPAAm brushes. A probe sequence of single-stranded DNA (ssDNA) with a 4-pentynoic acid succinimidyl ester unit was grafted onto the azido-terminated PNIPAAm brushes through a click reaction, resulting in the formation of block copolymer brushes. The PNIPAAm-b-ssDNA copolymer brushes formed supramolecular complexes stabilized by bio-multiple hydrogen bonds (BMHBs), which enhanced the proton transfer and thereby decreased the resistivity of the structures. In addition, the optimal operation window for DNA detection ranges from 0 to 0.2 M of NaCl concentration. Therefore, the specimens were prepared in the PBS solution at 150 mM NaCl concentration for target hybridization. The supramolecular complex state of the PNIPAAm-b-ssDNA copolymer brushes transformed into the phase-separated state after the hybridization with 0.5 ng/µL of its target DNA sequence owing to the competition between BMHBs and complementary hydrogen bonds. This phase transformation of the PNIPAAm and probe segments inhibited the proton transfer and significantly increased the resistivity at 25 °C. Moreover, there were no significant changes in the resistivity of the copolymer brushes after hybridization with the target sequence at 45 °C. These results indicated that the phase-separated state of the PNIPAAm-b-ssDNA copolymer brushes, which was generally occurred above the LCST, can be substantially generated after hybridization with its target DNA sequence. By performing the controlled experiments, in the same manner, using another sequence with lengths similar to that of the target sequence without complementarity. In addition, the sequences featuring various degrees of complementarity were exploited to verify the phase separation behavior inside the PNIPAAm-b-ssDNA copolymer thin film.

Characterization of poly(N-isopropylacrylamide)-nucleobase supramolecular complexes featuring bio-multiple hydrogen bonds.

In this study we employed poly(N-isopropylacrylamide) (PNIPAAm) as a matrix that we hybridized with five different nucleobase units (adenine, thymine, uracil, guanine, cytosine) to generate PNIPAAm-nucleobase supramolecular complexes (PNSCs) stabilized through bio-multiple hydrogen bonds (BMHBs). These nucleobase units interacted with PNIPAAm through BMHBs of various strengths, leading to competition between the BMHBs and the intramolecular hydrogen bonds (HBs) of PNIPAAm. The changes in morphology, crystalline structure, and thermoresponsive behavior of PNIPAAm were related to the strength of its BMHBs with the nucleobases. The strengths of the BMHBs followed the order guanine > adenine > thymine > cytosine > uracil, as verified through analyses of Fourier transform infrared spectra, lower critical solution temperatures, and inter-association equilibrium constants. The PNSCs also exhibited remarkable improvements in conductivity upon the formation of BMHBs, which facilitated proton transport. The neat PNIPAAm film was an insulator, but it transformed into a semiconductor after hybridizing with the nucleobases. In particular, the resistivity of the PNIPAAm-guanine supramolecular complex decreased to 1.35 × 10(5) ohm cm. The resistivity of the PNIPAAm-cytosine supramolecular complex increased significantly from 5.83 × 10(6) to 3 × 10(8) ohm cm upon increasing the temperature from 40 to 50 °C, suggesting that this material might have applicability in thermo-sensing. The ability to significantly improve the conductivity of hydrogels through such a simple approach involving BMHBs might facilitate their use as novel materials in bioelectronics.

Hydrogen-bonded cytosine-endowed supramolecular polymeric nanogels: Highly efficient cancer cell targeting and enhanced therapeutic efficacy.

We demonstrate that cytosine moieties within physically cross-linked supramolecular polymers not only manipulate drug delivery and release, but also confer specific targeting of cancer cells to effectively enhance the safety and efficacy of chemotherapy-and thus hold significant potential as a new perspective for development of drug delivery systems. Herein, we successfully developed physically cross-linked supramolecular polymers (PECH-PEG-Cy) comprised of hydrogen-bonding cytosine pendant groups, hydrophilic poly(ethylene glycol) side chains, and a hydrophobic poly(epichlorohydrin) main chain. The polymers spontaneously self-assemble into a reversibly hydrogen-bonded network structure induced by cytosine and directly form spherical nanogels in aqueous solution. Nanogels with a high hydrogen-bond network density (i.e., a higher content of cytosine moieties) exhibit outstanding long-term structural stability in cell culture substrates containing serum, whereas nanogels with a relatively low hydrogen-bond network density cannot preserve their structural integrity. The nanogels also exhibit numerous unique physicochemical characteristics in aqueous solution, such as a desirable spherical size, high biocompatibility with normal and cancer cells, excellent drug encapsulation capacity, and controlled pH-responsive drug release properties. More importantly, in vitro experiments conclusively indicate the drug-loaded PECH-PEG-Cy nanogels can selectively induce cancer cell-specific apoptosis and cell death via cytosine receptor-mediated endocytosis, without significantly harming normal cells. In contrast, control drug-loaded PECH-PEG nanogels, which lack cytosine moieties in their structure, can only induce cell death in cancer cells through non-specific pathways, which significantly inhibits the induction of apoptosis. This work clearly demonstrates that the cytosine moieties in PECH-PEG-Cy nanogels confer selective affinity for the surface of cancer cells, which enhances their targeted cellular uptake, cytotoxicity, and subsequent induction of programmed cell death in cancer cells.

Bioinspired assembly of functional block-copolymer nanotemplates.

A new concept on bioinspired assembly of functional diblock copolymers, capable of forming different microstructures through nucleobase-induced supramolecular interactions, has been explored. In this paper, a new series of uracil-functionalized poly(ε-caprolactone)-b-(4-vinylbenzyl uracil)s (PCL-b-PVBU) have been prepared which exhibit a high self-complementary ability in solution and solid states owing to the formation of uracil­uracil pairs by induced hierarchical self-assembly. The ordered morphologies of PCL-b-PVBU diblock copolymers changed from a lamellar, hexagonally packed cylinder to a sphere with respect to the content of the hydrogen bond segment. Moreover, we further show that the PCL segment could be easily extracted by enzymatic degradation, leading to a cylinder porous structure of long-range order, which gives a facile method for the fabrication of uracil-functionalized nanotemplates. In addition, bio-complementary PCL-b-PVBU/9-hexadecyladenine (AC16) hierarchical supramolecular complexes formed through strong cooperative hydrogen bonding between the uracil group of PVBU and the adenine group of A-C16. When the mixing ratios of PCL-b-PVBU/AC16 differ from the stoichiometric ratio, these complexes self-assemble into well-ordered lamellar and hexagonal structures; the changing morphology at different AC16 loadings reveals that the molecular structures of the PCL-b-PVBU/AC16 complexes are readily tailored.

Preparation of biofiltration membranes by coating electrospun polyacrylonitrile fiber membranes with layer-by-layer supermolecular polyelectrolyte films.

Electrospun polyacrylonitrile fiber membranes (EPFMs) were coated with multilayer films, assembled using the layer-by-layer (LbL) technique through the alternate deposition of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA), to develop an antithrombogenic drug release membrane for hemodialysis. Methylene blue (MB) and heparin (HEP) were attached to the PAH and PAA multilayers, respectively, as model drug and antithrombogenic agent to investigate the dual functionality of the membranes. The positively (PAH, MB) and negatively (PAA, HEP) charged groups generated a supermolecular polyelectrolyte multilayer film (SPF) capable of loading high amounts of MB and HEP on the EPFMs at appropriate composition. The pH was fixed at 5.5 during assembly to stabilize the SPF. Heavy assembly of the PAH/PAA multilayer occurred at 10 wt% of both MB and HEP with 25 cycles of LbL deposition, and it exhibited long-term release of MB and low release of HEP at pH 7.4 in a circulatory system. The SPF-coated EPFMs also achieved low platelet attachment after 4 h of platelet rich plasma circulation and showed prolonged clotting times including thromboplastin, thrombin, and prothrombin times. Collectively, these observations suggest that SPF-coated EPFMs have great potential for use as hemodialysis membranes with positively charged drug loading.

Electrorheological Sensor Encapsulating Microsphere Media for Plague Diagnosis with Rapid Visualization.

Plague is a disease infected by an etiological agent, which is transmitted from fleas to a variety of wildlife rodents. Therefore, rapid diagnosis of plague on-site in the field is important. Polystyrene microspheres (SMs) of 2.2 µm diameter were synthesized by emulsion polymerization to adsorb magnetic nanoparticles (FNs), resulting in core-/shell-structured microspheres that generate a significant contrast in relative permittivities between SMs and FNs. Electrorheological displays (EDs) consisting of two indium tin oxide glasses with spacers were constructed to contain core-/shell-structured SM/FN (SM@FN) solutions for observing their transmittance change. The ED encapsulating dispersed SM@FN solution exhibited an opaque state because light was scattered significantly without the application of an alternating electric field (AEF). In the presence of an AEF, the particle chaining behavior results in enhancement of the transmittance of ED. At a specific frequency, the so-called characteristic frequency (Fc), the transmittance reaches a maximum. Fc could be used as an indicator to mark the shell materials. The antibody of Yersinia pestis (ab-Yp) was coated onto the SM@FN as a biosensing medium. The Fc of ab-Yp-modified microspheres shifted from 200 to 750 kHz with antigen coupling of Y. pestis antigen (ag-Yp). In the absence of fluorescence labeling, the large change in ED transmittance could be visualized during the Y. pestis detection. The limit of detection and the limit of quantification were ∼30 and ∼40 ng/µL, respectively, obtained within 30 s according to the highest transmittance of ED under the AEF at 750 kHz. Y. pestis detection was not affected by Escherichia coli and Staphylococcus aureus significantly. Compared with other common immunoassays, including the secondary immunochemical or enzyme-linked steps, this simple electrorheological sensor with high sensitivity and selectivity could be a candidate for on-site plague diagnosis.

Surface lattice resonance of line array of poly (glycidyl methacrylate) with CdS quantum dots for label-free biosensing.

One dimensional plasmonic grating is a kind of resonant electromagnetic wave absorber with a characteristic wavelength. This study focusses on one-dimensional plasmonic grating consisting of poly (glycidyl methacrylate) (PGMA) brushes and CdS quantum dots (CdQDs) fabrication and PGMA chains grafted on a primary substrate in a line array continued by the immobilization of biotin-modified CdQDs. PGMA brush line array (PBLA) of plasmonic grating exhibited an absorptance at 441 nm while at the same time, CdQDs immobilized with PBLA showed characteristic absorbance at 396 nm. The blue-shift from 441 nm matches the absorbance peak of biotin-modified CdQDs resulting in the enhancement of photoluminescence emission of CdQDs. With streptavidin incubation to assemble CdQDs at 50 nM, the significant decrease in grating height resulted in the red-shift of the absorbance peak to 536 nm. Due to the deviation in absorbance, the intensity of the PL emission decreased gradually with the increase in concentration of streptavidin. In addition, our results showed that streptavidin incubation altered the color reflected from the surface due to effective changes in the refractive index of the layer as well. The limit of detection of the grating for streptavidin detection was determined to be 50 nM. Thus, PBLA-CdQD has the potential to act as a highly-sensitive, label-free optical biosensor.

Self-assembled supramolecular polymers with tailorable properties that enhance cell attachment and proliferation.

Self-assembled supramolecular scaffolds, a combination of noncovalent interactions within a biocompatible polymer substrate, can be used for efficient construction of highly-controlled self-organizing hierarchical structures; these newly-developed biomaterials exhibit excellent mechanical properties, tunable surface hydrophilicity, low cytotoxicity and high biodegradability, making them highly attractive for tissue engineering and regenerative medicine applications. Herein, we demonstrate a novel supramolecular poly(ε-caprolactone) (PCL) containing self-complementary sextuple hydrogen-bonded uracil-diamidopyridine (U-DPy) moieties, which undergoes spontaneous self-assembly to form supramolecular polymer networks. Inclusion of various U-DPy contents enhanced the mechanical strength and viscosities of the resulting materials by up to two orders of magnitude compared to control PCL. Surface wettability and morphological studies confirmed physically-crosslinked films can be readily tailored to provide the desired surface properties. Cell viability assays indicated the excellent in vitro biocompatibility of U-DPy-functionalized substrates and indicate the potential of these materials for various biomedical applications. More importantly, mouse fibroblast NIH/3T3 cells cultured on these substrates displayed a more elongated cell morphology and had substantially higher cell densities than cells seeded on control PCL substrate, which indicates that introduction of U-DPy moieties into polymer matrixes could be used to create tissue culture surfaces that enhance cell attachment and proliferation. This new system is suggested as a potential route towards the practical realization of next-generation tissue-engineering scaffolds. STATEMENT OF SIGNIFICANCE: In this study, we report a significant breakthrough in development of self-assembled supramolecular polymers to form well-defined scaffolds through self-complementary hydrogen-bonding interactions. These newly developed materials exhibited extremely good mechanical properties, fine-tunable hydrophilic characteristics and excellent biocompatibility due to hydrogen-bond-induced physical cross-linking. Importantly, cell adhesion and proliferation assays indicated that these substrates efficiently promoted the growth of mouse embryonic fibroblasts NIH/3T3 cells in vitro. Thus, this finding provides a simple and effective route for the development of next-generation tissue-engineering scaffolds that have improved mechanical properties, increased surface hydrophilicity and can enhance the growth and biological activity of adherent cells.

Supermolecules of poly(N-isopropylacrylamide) complexating Herring sperm DNA with bio-multiple hydrogen bonding.

In this study we used the poly(N-isopropylacrylamide) (PNIPAAm) as a medium to blend with an organic DNA, herring sperm DNA (HSD), to generate PNIPAAm-HSD supramolecular complexes. Bio-multiple hydrogen bonding (BMHB) between PNIPAAm and HSD was investigated that changed the temperature responsiveness of PNIPAAm relatively to the HSD concentrations. With blending the HSD into PNIPAAm matrix, the phase separation in solution is completely opposite from that of neat PNIPAAm. Surface property in static water contact angle (SWCA) is also opposite from that of pure PNIPAAm upon increasing HSD content over 60%. In addition, we found that the PNIPAAm and HSD self-assembled a specific triangle-like structure at a PNIPAAm-to-HSD weight ratio of 1:4 at 25°C; while the triangle-like structure disappeared with increasing temperature to 45°C. Furthermore, both PNIPAAm and HSD could be regarded as insulator, but it transformed into a semiconductive matter after blending with the HSD. Incorporation of organic DNA with hydrogel could significantly change their properties, which might facilitate their use as novel materials in bioelectronics.

Nucleobase-Functionalized Supramolecular Micelles with Tunable Physical Properties for Efficient Controlled Drug Release.

Complementary nucleobase-functionalized polymeric micelles, a combination of adenine-thymine (A-U) base pairs and a blend of hydrophilic-hydrophobic polymer pairs, can be used to construct 3D supramolecular polymer networks; these micelles exhibit excellent self-assembly ability in aqueous solution, rapid pH-responsiveness, high drug loading capacity, and triggerable drug release. In this study, a multi-uracil functionalized poly(ε-caprolactone) (U-PCL) and adenine end-capped difunctional oligomeric poly(ethylene glycol) (BA-PEG) are successfully developed and show high affinity and specific recognition in solution owing to dynamically reversible A-U-induced formation of physical cross-links. The U-PCL/BA-PEG blend system produces supramolecular micelles that can be readily adjusted to provide the desired critical micellization concentration, particle size, and stability. Importantly, in vitro release studies show that doxorubicin (DOX)-loaded micelles exhibit excellent DOX-encapsulated stability under physiological conditions. When the pH value of the solution is reduced from 7.4 to 5.0, DOX-loaded micelles can be rapidly triggered to release encapsulated DOX, suggesting these polymeric micelles represent promising candidate pH-responsive nanocarriers for controlled-release drug delivery and pharmaceutical applications.

Highly efficient drug delivery systems based on functional supramolecular polymers: In vitro evaluation.

The novel concept of modifying and enhancing the properties of existing functional micelles through self-complementary interactions has significant potential. In this study, a practical approach to living polymerization of functionalized thermoresponsive monomers enabled the incorporation of self-constituted multiple hydrogen bonded groups into micelles that have potential as supramolecular drug-delivery systems. Phase transitions and morphological studies in aqueous solution showed that the microstructure can be controlled to achieve well-defined vesicle-like micelles with respect to the strength of the hydrogen bond segment. Thus, the resulting micelles have a very low critical micellization concentration and very high loading capacity (16.1%), making the loading process extremely stable and efficient. Incorporation of the anticancer drug doxorubicin (DOX) affected the micellization process in aqueous solution and enabled fine-tuning of drug loading and precise control of drug release rate with excellent sensitivity. Release studies in vitro showed that DOX-loaded micelles exerted dose-dependent cytotoxicity against human liver carcinoma (HepG2) cells at the physiological temperature of 37°C. In addition, DOX-loaded micelles were efficiently endocytosed by the cancer cells, which may enable the micelles to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. This newly developed material may provide a potential route towards next-generation drug delivery vehicles. STATEMENT OF SIGNIFICANCE: A breakthrough innovation in water-based thermo-responsive polymers has enabled significant progress in developing smart stimuli-responsive nanocarriers by generating novel "supramolecular polymeric micelles" via self-complementary hydrogen-bonding interactions. These newly developed micelles exhibit extremely high micellar stability and drug loading capacity (up to 16%), excellent thermo-responsive behavior and precise control of drug release rate due to hydrogen-bond-induced physical cross-linking. In addition, doxorubicin-loaded micelles were efficiently endocytosed by the cancer cells, which allows them to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. Thus, this work provides a potential route for the development of next generation multifunctional nanocarriers that have improved safety and to increase the therapeutic efficacy of anticancer therapy.

Rapid fabrication of carbon quantum dots as multifunctional nanovehicles for dual-modal targeted imaging and chemotherapy.

Herein, we synthesized an S, N, and Gd tri-element doped magnetofluorescent carbon quantum dots (GdNS@CQDs) within 10min by using a one-pot microwave method. Our results showed that these magnetofluorescent GdNS@CQDs have excellent fluorescent and magnetic properties. Moreover, GdNS@CQDs exhibited high stability at physiological conditions and ionic strength. These magnetofluorescent GdNS@CQDs were conjugated with a folic acid, denoted as FA-GdNS@CQDs, for targeting dual modal fluorescence/magnetic resonance (MR) imaging. The in vitro and in vivo studies confirmed the high biocompatibility and low toxicity of FA-GdNS@CQDs. FA-GdNS@CQDs enhanced the MR response as compared to that for commercial Gd-DTPA. The targeting capabilities of FA-GdNS@CQDs were confirmed in HeLa and HepG2 cells using in vitro fluorescence and MR dual modality imaging. Additionally, an anticancer drug, doxorubicin, was incorporated into the FA-GdNS@CQDs forming FA-GdNS@CQDs-DOX, which enables targeted drug delivery. Importantly, the prepared FA-GdNS@CQDs-DOX showed a high quantity of doxorubicin loading capacity (about 80%) and pH-sensitive drug release. The uptake into cancer cells and the intracellular location of the FA-GdNS@CQDs were observed by confocal laser scanning microscopy. We also successfully demonstrated in vivo fluorescence bio imaging of the FA-GdNS@CQDs, using zebrafish as an animal model. STATEMENT OF SIGNIFICANCE: In this manuscript, we reported a facial, rapid, and environmental friendly method to fabricate hetero atoms including gadolinium, nitrogen, and sulfur doped multi-functional magnetofluorescent carbon quantum dots (GdNS@CQDs) nanocomposite. These multifunctional GdNS@CQDs were conjugated with a folic acid for targeting dual modal fluorescence/magnetic resonance imaging. Additionally, an anticancer drug, doxorubicin, was incorporated into the nanocomposite forming FA-GdNS@CQDs-DOX, which enables targeted drug delivery. We have developed GdNS@CQDs with integrated functions for simultaneous in vitro cell imaging, targeting, and pH-sensitive controlled drug release in HeLa cells. Furthermore, we successfully demonstrated the use of this material for in vivo fluorescence imaging, using zebrafish as an animal model.

Synthesis of tethered poly(N-isopropylacrylamide) for detection of breast cancer recurrence DNA.

We have grafted temperature-responsive tethered poly(N-isopropylacrylamide) (PNIPAAm) onto silicon surfaces through atom transfer radical polymerization (ATRP) as a medium to extract human genomic DNA molecules from a biological specimen, namely human blood incorporating target DNA (hgDNA584) and control DNA (hgDNA528) at concentrations of 0.5, 1, and 50 ng µL(-1). The variable adhesion forces of the tethered PNIPAAm brushes on the surfaces were used to capture and release DNA molecules through changes in temperature. After amplifying the signal of the hgDNA584 and hgDNA528 strands released from the tethered PNIPAAm on the substrate using the polymerase chain reaction (PCR), we identified these DNA macromolecules using agarose gel electrophoresis. The accuracy of the detection of hgDNA584 and hgDNA528 was controlled through the design of specific primers in the PCR process. The quantities of these two DNA molecules obtained through the capture and release from tethered PNIPAAm brushes under temperature tuning conditions were sufficient for them to be amplified recognizably, suggesting that this approach could be used in miniaturized lab-on-a-chip cartridges for rapid disease diagnosis.

Fabrication of high-aspect-ratio poly(2-hydroxyethyl methacrylate) brushes patterned on silica surfaces by very-large-scale integration process.

We used a novel fabricated process including electron beam and isotropic oxygen plasma to generate signal line patterns of polymerized 2-hydroxyethyl methacrylate (HEMA) on patterned Si(1 0 0) surfaces. Isotropic oxygen plasma was introduced to enhance the resolutions of the line and dots patterns of the PHEMA brush are approached to 350 nm and 2 µm, respectively. We established the surface grafting polymerization kinetics of the PHEMA chains on silicon surface by to fit the thickness and number-average molecular weight (M(n)). The propagation rate (k(p)) and active grafting specie deactivation rate (k(d)) lies in the range of ~3.6 × 10(-2) s(-1) M(-1) and 4.8 × 10(-5) s(-1), respectively. The measured thicknesses by ellipsometer and analyzed M(n) of "free" PHEMA by gel permeation chromatography (GPC) are fitted well by the polymerization kinetic model. In addition, aspect-ratios (height/width) are used to define the shape of patterned PHEMA brushes. The high-aspect-ratio of the PHEMA brush line with width of 350 nm is 0.27. We use a graft polymerization/solvent immersion method for generating various patterns of polymer brushes to investigate the deformation of the PHEMA brush through aspect-ratios.

Characterization of patterned poly(methyl methacrylate) brushes under various structures upon solvent immersion.

In this paper we describe a graft polymerization/solvent immersion method for generating various patterns of polymer brushes. We used a very-large-scale integration (VLSI) process and oxygen plasma system to generate well-defined patterns of polymerized methyl methacrylate (MMA) on patterned Si(100) surfaces through atom transfer radical polymerization (ATRP). After immersion of wafers presenting lines of these PMMA brushes in water and tetrahydrofuran, we observed mushroom- and brush-like regimes through grafting densities and surface coverages, respectively, for the PMMA brushes with various pattern resolutions. In the mushroom-like regime, the distance between lines of PMMA brushes was smaller than that of the lines patterned lithographically on the wafer; in the brush-like regime, this distance was approximately the same. This new strategy allows polymer brushes to be prepared through graft polymerization and then have their patterns varied through solvent immersion.