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Objective To propose a novel free-hand pedicle screw placement technique in the lumbar spine and investigate its accuracy and safety in clinical practice. Methods 110 patients with herniation of a single lumbar disc were recruited for our study. All patients were consistently treated with posterior discectomy, interbody fusion, and transpedicular internal fixation. For 54 patients in the observation group, the pedicle screws were placed with our technique, which is located at 4 mm below the superior edge of the transverse process in line with the lateral margin of the superior articular process. For 56 patients in the control group, pedicle screws were placed according to the traditional crista lambdoidalis method. Comparisons were made in terms of the operation time, blood loss, time for exposure, the accuracy of placement, and postoperative complications. In addition, we prospectively applied our method to 64 patients with indistinguishable crista lambdoidalis and evaluated the accuracy of screw placement and clinical outcomes. Results There was no significant difference in intraoperative bleeding, accuracy of placement, and postoperative complications between our technique and the traditional crista lambdoidalis method (P > 0.05). However, the exposure time before screw placement (12.8 ± 0.3 vs 17.4 ± 0.3, p = 0.001) and the total surgery time (97.2 ± 1.9 vs 102.3 ± 0.9, p = 0.020) were significantly shortened with our method. Additionally, in cases of indistinguishable crista lambdoidalis, our technique showed satisfying accuracy, with 97.6% screws placed in appropriate trajectory on the first attempt and all screws eventually positioned in the safe zone according to the Gertzbein Robbins grading. All patients experienced steady improvement after surgery, as assessed with the visual analog pain scale and the Japanese Orthopaedic Association (JOA) score. Conclusion This study highlights a safe and effective technique for pedicle screw placement in the lumbar spine, which is particularly useful in cases of vertebral fracture and severe hyperplasia or degeneration of the facet joint.

OBJECTIVES This study was to explore the effects of teramethylpyrazine (TMP) administered in conjunction with neural stem cell transplantation on motor function, pathological lesions and the Janus kinase (JAK)2/signal transducer and activator of transcription 3 signal transduction pathway in rats following acute spinal cord injury (SCI). METHODS Female Sprague-Dawley rats were randomly divided into sham, model, neural stem cells (NSCs) and NSCs+TMP groups. Motor function was evaluated using the Basso, Beattie, Bresnahan scale. Spinal cord neuropathies and neuron apoptosis were observed by HE and TUNEL staining. The brain-derived neurotrophic factor (BDNF), Nogo-A, JAK2 and p-JAK2 protein levels were measured by western blot analysis. RESULTS NSCs+TMP significantly improved rat motor function, attenuated impaired spinal cords, and decreased cellular apoptosis, compared with NSCs therapy alone (P < 0.05). In addition, expression of BDNF protein was significantly higher in NSCs+TMP rats compared with other groups regardless of time postinjury (P < 0.05). The highest expression levels of Nogo-A protein were observed in the model group. The expression of p-JAK2 in the NSCs+TMP group was relatively lower than the model and NSCs groups (P < 0.05). CONCLUSIONS In rats with SCI, NSCs+TMP effectively improved motor function and offered spinal cord protection by increasing BDNF and decreasing Nogo-A levels, as well as inhibiting the JAK2/STAT3 signal transduction pathway, suggesting that TMP could be a useful agent in NSCs transplantation in the treatment of SCI.

Background N-methyl-D-aspartate (NMDA) receptors are ligand-gated ion channels that mediate excitatory synaptic transmission in the central nervous system. The functional NMDA receptors are heterotetramers consisting mainly of two GluN1 and two GluN2 subunits. GluN2 is encoded by the GRIN2D gene. A few case series have shown that GRIN2D variants are linked to developmental and epileptic encephalopathy. In this article, we report a novel GRIN2D variant, namely c.2021C > A (p.T674K) in a neonate with intractable epileptic encephalopathy. Case presentation A 12-day-old boy who had stiffness of the lower and upper extremities since birth was transferred from a local hospital to our department. On admission, the patient presented with head tilting backwards, staring, apnea and hypertonia of limbs. Video electroencephalogram showed continuous, generalized or multi-focal spike-wave and spike-and-slow wave discharges and hypsarrhythmia. A treatment regimen composed of phenobarbital, midazolam, levetiracetam and clonazepam was administered, which however led to only partial control of the seizure. Whole-exome sequencing identified c.2021C > A (p.T674K) in GRIN2D in the patient while such a mutation was not detected in the parents. The patient was hospitalized for 1 month and died of sudden cardio-respiratory arrest 2 weeks after discharge. Conclusions A novel variant of GRIN2D was identified in a neonate with epileptic encephalopathy. Epilepsy associated with this GRIN2D mutation is refractory to conventional anti-epileptic medications.

Background The aim of this study was to identify important miRNAs and their target genes involved in cell apoptosis in intervertebral disc degeneration (IDD) patients. Methods The dataset, GSE63492, was obtained from the gene expression omnibus platform. After preprocessing, the differentially expressed miRNAs (DEMs) and their target genes were identified using the Limma package and miRWalk2.0 database, respectively. The clusterProfiler package in R was used to perform functional enrichment analysis of these target genes. Subsequently, protein-protein interaction (PPI) network and subnet clusters of the coregulated genes were conducted using the STRING database and MCODE, respectively. Further, the co-regulatory network of the key miRNAs and PPI networks were visualized using Cytoscape. Finally, cell apoptosis-related pathways and the genes enriched in these pathways were identified. Results The genes targeted by the upregulated (hsa-miR-302c-5p, hsa-miR-631, hsa-let-7f-1-3p, hsa-miR-3675-3p, and hsa-miR-585-3p) and downregulated miRNAs (hsa-miR-185-5p, hsa-miR-486-5p, hsa-miR-4306, and hsa-miR-4674) were interrelated with cell apoptosis-related pathways. MAPK1 and MAPK3 were targeted by hsa-miR-185-5p, while GSK3B was targeted hsa-miR-4306, hsa-miR-486-5p, hsa-miR-185-5p, hsa-let-7f-1-3p, and hsa-miR-631. Besides, MAPK3 and VEGFA were regulated by hsa-miR-3675-3p and hsa-miR-631, respectively. Conclusions The expression of GSK3B may be coregulated by miR-4306, miR-185-5p, miR-486-5p, hsa-let-7f-1-3p, and miR-631 and may affect IDD development. Besides, miR-185-5p and miR-3675-3p may control nucleus pulposus (NP) cell apoptosis through the MAPK signaling pathway in IDD patients. VEGFA expression may be regulated by miR-631, and help maintain NP cell survival in IDD patients. Our findings may help guide further research into the role of miRNAs in IDD progression.

Purpose: A three-dimensional finite element model of the lower cervical spine was established to evaluate the biomechanical stability and stress distribution of the new lower cervical interzygapophyseal fusion device (IZFD) developed by ourselves under different construct. The aim of this study was to provide theoretical basis for further clinical application. Methods: A normal fresh cadaveric specimen (male, 35 years old) was used to establish an intact three-dimensional finite element model of C3–C6. On this basis, the comparative finite element models of the lateral mass screw rod (LMSR) system and LMSR+IZFD were established. Only C4–C5 is fixed in the lateral mass. The range of motion (ROM) and stress distribution in the flexion, extension, lateral bending and rotation of the C4–C5 segment under the three constructs were analyzed. Results: The ROM and stress distribution of the three-dimensional finite element model under load construct were within a reasonable range, which proved the validity and reliability of the model. The ROM and stress distribution of C4–C5 segment was significantly decreased in both LMSR and LMSR+IZFD constructs than those in the intact construct. The ROM and stresss distribution were even smaller in LMSR+IZFD construct than in LMSR construct. Conclusions: The IZFD combined with LMSR system can provide satisfactory stability for the lower cervical spine, and the IZFD can further improve the fixation effect of the LMSR system.

A vector bending fiber sensor based on core-by-core inscribed fiber Bragg gratings in a twin-core fiber has been proposed and experimentally demonstrated. An in-fiber integrated vector bending sensor is realized by using the thermal diffusion technique to fabricate the coupler. The characteristics of the coupler fabricated by thermal diffusion are simulated and experimented. By inscribing fiber Bragg gratings with different reflection wavelengths in the two cores of a symmetrical twin-core fiber, the curvature sensitivity can be enhanced by tracking the wavelength difference between the fiber Bragg gratings of the two cores. The measured bending sensitivity of the fiber Bragg grating ranges from −161.6 pm/m−1 to +165.5 pm/m−1. The differential sensitivity of the two cores is twice that of a conventional single grating, and the temperature-induced crosstalk is also reduced. The bending sensor proposed in this paper has the advantages of high integration, enhancing the sensitivity and two-dimensional orientation recognizability, and reducing temperature crosstalk, which can be a promising candidate for structural health monitoring or wearable artificial electronics applications.

The transient elevation of cytoplasmic calcium is essential for pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). However, the calcium channels responsible for this process have remained unknown. Here, we show that rice CDS1 (CELL DEATH and SUSCEPTIBLE to BLAST 1) encoding OsCNGC9, a cyclic nucleotide-gated channel protein, positively regulates the resistance to rice blast disease. We show that OsCNGC9 mediates PAMP-induced Ca(2+) influx and that this event is critical for PAMPs-triggered ROS burst and induction of PTI-related defense gene expression. We further show that a PTI-related receptor-like cytoplasmic kinase OsRLCK185 physically interacts with and phosphorylates OsCNGC9 to activate its channel activity. Our results suggest a signaling cascade linking pattern recognition to calcium channel activation, which is required for initiation of PTI and disease resistance in rice.

Nonketotic hyperglycinemia (NKH) is a lethal autosomal recessive disease resulting from alterations in glycine metabolism, commonly caused by mutations in glycine decarboxylase (GLDC). The symptoms of NKH usually manifest in the neonatal period, and can be categorized into severe NKH and attenuated NKH based on the clinical outcome. To date, only a few NKH cases have been reported in China. We here report a case of a neonate with severe NKH carrying a novel compound heterozygous variant in GLDC. The patient was a 68-h-old girl who had progressive lethargy, no crying, and poor sucking ability from birth, and was therefore transferred to our department. On admission, the patient was supported by intubation and ventilation and presented with profound coma. Metabolic investigation indicated a markedly increased glycine concentration both in the plasma and cerebrospinal fluid (CSF). Symptomatic treatments were administered, but the patient's condition did not improve substantially. Whole-exome sequencing identified compound heterozygous mutations (c.1261G>C, p.G421R and c.450 C>G, p.N150K) in GLDC, which were inherited from the mother and the father, respectively. The patient was hospitalized for 8 days in our department and died 2 days after discharge. We further summarize the clinical features, genetic characteristics, administered treatment, and prognosis of previously reported Chinese NKH patients for context. Our results highlight that due to the non-specific clinical phenotypes of NKH and difficulty in obtaining CSF samples, genetic testing is a crucial tool, not only for a diagnosis but also for predicting the clinical outcome and can potentially help to determine the optimal therapeutic strategy.

Honeycomb materials have low density, high specific strength and stiffness, impact resistance, and good sound insulation effect, and therefore are widely used in aerospace, automobile, and ship field applications. In this paper, we study the in-plane impact response of a second-order hierarchical honeycomb (SHH) material. Its main structure is a hexagonal honeycomb, and the substructure is composed of an augmented double arrow honeycomb (ADAH) negative Poisson’s ratio unit. Through a finite element simulation, the failure stress of an hierarchical honeycomb in two directions of quasi-static crushing and dynamic crushing was analyzed, the failure stress of the hierarchical honeycomb under different densities, different speeds, and different substructures was discussed, and the theoretical failure stress was verified. The numerical analysis results show that a second-order hierarchical honeycomb (SHH) has better collapse stress than a first-order regular hexagonal honeycomb (FHH) and an augmented double arrow honeycomb (ADAH).

Anthocyanins cause purple, brown or red colors in various tissues of rice plants, but the specific determinant factors and regulatory systems for anthocyanin biosynthesis in almost all tissues remain largely unknown. In the present study, we mapped and isolated two complementary genes, OsC1 encoding a R2R3-MYB transcriptional factor and OsDFR encoding a dihydroflavonol 4-reductase, which are responsible for the purple coloration of apiculi and stigmas in indica cultivar Xieqingzao by the map-based cloning strategy. We also identified two tissue-specific pigmentation genes, OsPa for apiculi and OsPs for stigmas, by phylogenetic analysis of all anthocyanin biosynthesis-associated bHLH transcriptional factors in maize and rice, CRISPR/Cas9 knockout and transcriptional expression analysis. The OsC1, OsPa and OsPs proteins are all localized in the nucleus while the OsDFR protein is localized in the nucleus and cytoplasm, and the OsC1 and OsDFR genes are preferentially strongly expressed in both purple-colored tissues while the OsPa and OsPs genes are preferentially strongly expressed in apiculi and stigmas, respectively. OsC1 specifically interacts with OsPa or OsPs to activate OsDFR and other anthocyanin biosynthesis genes, resulting in purple-colored apiculi or stigmas. OsC1 itself does not produce color but can produce brown apiculi when functioning together with OsPa. Loss of function of OsDFR alone leads to brown apiculi and straw-white stigmas. Genotyping and phenotyping of a panel of 176 rice accessions revealed diverse genotypic combinations of OsC1, OsDFR, OsPa and OsPs that enable accurate prediction of their apiculus and stigma pigmentation phenotypes, thus validating the general applicability of the OsC1-OsDFR-OsPa and OsC1-OsDFR-OsPs models to natural populations. Our findings disclosed the biological functions of OsC1, OsPa and OsPs, and shed light on the specific regulatory systems of anthocyanin biosynthesis in apiculi and stigmas, a further step in understanding the regulatory network of anthocyanin biosynthesis in rice.

Additional file 15: Table S3. Amino acids sequences alignment of three bHLH transcription factors.

Additional file 20: Table S8. Analysis of haplotype combinations of the OsC1, OsDFR, OsPa and OsPs genes in lines with apiculus and stigma colors.

Summary Lesion mimic mutants that exhibit spontaneous hypersensitive response (HR)‐like necrotic lesions are ideal experimental systems for elucidating molecular mechanisms involved in plant cell death and defence responses. Here we report identification of a rice lesion mimic mutant, spotted leaf 35 (spl35), and cloning of the causal gene by TAIL‐PCR strategy. spl35 exhibited decreased chlorophyll content, higher accumulation of H2O2, up‐regulated expression of defence‐related marker genes, and enhanced resistance to both fungal and bacterial pathogens of rice. The SPL35 gene encodes a novel CUE (coupling of ubiquitin conjugation to ER degradation) domain‐containing protein that is predominantly localized in cytosol, ER and unknown punctate compartment(s). SPL35 is constitutively expressed in all organs, and both overexpression and knockdown of SPL35 cause the lesion mimic phenotype. SPL35 directly interacts with the E2 protein OsUBC5a and the coatomer subunit delta proteins Delta‐COP1 and Delta‐COP2 through the CUE domain, and down‐regulation of these interacting proteins also cause development of HR‐like lesions resembling those in spl35 and activation of defence responses, indicating that SPL35 may be involved in the ubiquitination and vesicular trafficking pathways. Our findings provide insight into a role of SPL35 in regulating cell death and defence response in plants.

The recovery of spinal cord injury (SCI) involves multiple factors, of which miRNAs take an important part. In this study, we evaluated the function of microRNA-211-5p (miR-211-5p) on SCI in a rat model. SCI model was established using modified Allen's weight-drop method and Basso-Bcattie-Bresnahan score was applied to assess the locomotor function. MiR-211-5p agomir was utilized to increase miR-211-5p expression and endoplasmic reticulum (ER) stress inhibitor, 4-PBA (4-phenylbutyric acid), was utilized to suppress ER stress. Neuron apoptosis and the expressions of miR-211-5p, activating transcription factor 6 (ATF6), apoptosis-related proteins, pro-inflammatory cytokines and endoplasmic reticulum stress-related proteins were detected. Dual luciferase reporter gene assay was performed to verify the binding between miR-211-5p and ATF6. The results showed that miR-211-5p directly targeted ATF6. MiR-211-5p was down-regulated and ATF6 was up-regulated in SCI rats. Both interferences with miR-211-5p agomir and 4-PBA effectively attenuated neuron apoptosis and reversed the expressions of apoptosis, inflammation and endoplasmic reticulum stress-related molecules post SCI in rats. These findings demonstrated that miR-211-5p could effectively alleviate SCI-induced neuron apoptosis and inflammation via directly targeting ATF-6 and regulating ER stress.

F. suspense is not only an important traditional Chinese medicine and but also an excellent urban greening tree species, thus has important economic and ecologic values. However, the lack of gene resources limits the molecular biology and gene functional studies in F. suspensa . In this study, the transcriptome of the mixed samples from root, stem, leaf, flower and fruit of F. suspensa was sequenced using the Illumina HiSeqTM 2500 sequencing platform. After high through-put sequencing, a total of 23164327 clean reads with 4678791021 bp were obtained. The clean reads were then de novo assembled into 45112 unigenes, and 28699 unigenes were annotated by a similarity search against five public databases. Of these annotated unigenes, 473 genes were assigned to second metabolic pathway, including 81 genes associated with phenylalanine and phenylpropanoid metabolism. Further analysis of these 81 genes reveled that there were 4 genes encoding phenylalanine ammonia-lyase, 1 gene encoding cinnamate 4-hydroxylase and 2 genes encoding 4-coumarate: CoA ligase, respectively. These enzymes are involved in the biosynthesis of cinnamic acid derivatives, which are precursors of the mainly pharmaceutically active substances phenylethanoid glycosides and lignan in F. suspensa . In addition, we also identified 2 pinoresinol/lariciresinol reductase encoding genes and 1 secoisolariciresinol dehydrogenase encoding gene, which are the key genes in the lignan biosynthesis. Finally, a total of 3199 SSRs were identified from 12721 unigenes longer than 1 kb, and 40 of them were verified. This work not only provides many valuable basal data for gene cloning and molecular biology research, but also lays the foundation for genetic diversity analysis, finger printing construction and molecular marker assisted breeding in F. suspensa .

In vitro plant regeneration requires the coordinated action of various enzymes in addition to phytohormones. Here, we report that the Arabidopsis Branching Enzyme 1 (BE1) gene, encoding a putative glycoside hydrolase involved in carbohydrate metabolism, is critical for explant regeneration. A partial loss-of-function mutation of the BE1 gene (be1-3 mutant) severely impaired adventitious shoot formation and somatic embryogenesis but not root formation in tissue culture. An in planta hormone response assay revealed that be1-3 seedlings showed normal response to cytokinin and auxin. The calli formed from be1-3 mutants were less plump than those of wild type hypocotyls. The BE1 gene is mainly expressed in the xylem pericycle of the hypocotyl and root and in dedifferentiated and differentiating calli. Expression levels of BE1 decreases gradually during shoot formation. Consistent with its role in carbohydrate metabolism, mutation of the BE1 gene dramatically reduces the content of glucose and fructose in seeds. Transcriptomic profiles showed 1,860 and 832 differentially expressed genes between the mutant and wild type during callus and shoot development, respectively. Most of them were related to metabolism, hormone signal transduction and stress response. These results indicate that the BE1 gene is involved in organogenesis and somatic embryogenesis by regulating carbohydrate metabolism.

This study shows that C60 can degrade pBR322 plasmid DNA at room temperature without photoactivation. The degradation was enhanced by increasing incubation temperature, reaction time or C60 concentration. We also found that superoxide radical anions (O 2 −· ) were formed in the C60 solution. Superoxide dismutase significantly inhibited DNA cleavage and O 2 −· generation induced by C60. These results suggest that DNA cleavage was caused by the formation of reactive oxygen species induced by C60 at room temperature. Furthermore, we demonstrate that the DNA degradation was significantly inhibited by acid amide chemicals such as formamide, and by increased ionic strength of the reaction solution. These results indicate that the DNA conformation stability and the surface properties of C60 are important factors regulating DNA degradation. We propose that C60 can bind DNA, decrease DNA conformation stability, and induce the formation of reactive oxygen species and DNA cleavage at room temperature. Our results provide a possible explanation for the genotoxicity of C60, which should be considered in future use of this particular nano-material.

Two fluorescent anion receptors (1 and 2) based on amide macrocycle were synthesized and corresponding fluorescence quenching induced by anion complexation was observed in different degree. Receptors form 1:1 complexes with anions by hydrogen bonding interactions. Receptor 1 bound anions in the order of F->Cl- > H2PO4−- CH3COO− > >Br−, I− and receptor 2 showed high selectivity to F− over other anions.

Two new neutral receptors (1 and 2) containing (thio) urea and amide groups were synthesized by simple steps in good yields. The binding properties for anions of 1 and 2 were characterized by UV-vis and fluorescence spectra. Receptor 1 had an excellent selectivity for AcO− in comparison with other anions. The association constants of 1 · AcO− and 2 · p-NO2PhOPO23− were higher than those of other anions (Cl−, Br−, I−, H2PO−4 and p-NO2PhO−). In particular, an obvious color change was observed from light yellow to golden yellow upon addition of AcO− to the solution of 1 in DMSO. The results of non-linear curve fitting by UV-vis and fluorescence spectral data indicate that a 1:1 stoichiometry complex is formed between compound 1 or 2 and anions through a hydrogen bonding interaction.

Three new chiral heterocalix [4] crowns containing aza thio atoms bearing two chiral sites provided by (R)-cysteine ester were synthesized. All new compounds were characterized by 1H NMR, MS and elemental analysis.

Thermo-sensitive amphiphilic copolymers, PVCL-PTrpAMT and PVCL-PVP-PTrpAMT of hydrophilic N-vinylcaprolactam (VCL), N-vinylpyrrolidone (NVP), and hydrophobic N-t-Boc-tryptophanamido-N'-methacryl thioureas (TrpAMT) monomers, were synthesized and characterized by (1)H NMR, UV-spectroscopy, and GPC-MALLS. The cloud point (CP) measurement showed that hydrophobic PTrpAMT and hydrophilic PVP segments significantly altered the phase transition temperature of PVCL with comparable molecular weight in aqueous solution. The CP of PVP-PTrpAMT solution was 38.0 degrees C, lower by 5.0 degrees C than that of unmodified PVCL. In the presence of phosphate buffer saline (PBS), the CP value of the PVCL polymer decreased by similar to 2.0 degrees C in comparison to that of the aqueous solution. Fluorescent spectroscopy and TEM studies revealed that PVCL-PTrpAMT and PVCL-PVP-PTrpAMT self-assembled into the spherical micelles, 30-70 nm in diameter, at concentrations over their CMCs in an aqueous solution. Cytotoxicity tests demonstrated that the PVCL copolymers were not harmful to cell viability, which may favor the use of the copolymers as potential thermo-sensitive polymers in pharmaceutical applications. Copyright (c) 2009 John Wiley a Sons, Ltd.

Highly active catalysts mediating atom transfer radical polymerization (ATRP) at low concentrations, therefore requiring no postpolymerization catalyst removal, are highly desirable for wide commer...

Interactions of amphiphilic copolymer poly(N-vinylpyrrolidone-co-N-t-Boc-tryptophanamido-N'-methacrylthiourea) [P(NVP-co-TrpAMT)] and poly(N-vinylpyrrlidone) (PVP) with DNA were studied with the aim to understand the difference in their complexation efficiencies when considered as a potential non-viral delivery vector. Fluorescence spectroscopy, ethidium bromide (EB) quenching, zeta potential measurement, and agarose gel electrophoresis were all carried out in Tris-HCl (pH 7.4) solution to assess the degree of interaction between the (co)polymers P(NVP-co-TrpAMT) and DNA. All of these measurements show that the high affinity of the copolymer for DNA can be demonstrated. We also found that P(NVP-co-TrpAMT)-I (PVP/PTrpAMT molar ratio was 100:2.88) exhibited a high DNA cleavage activity and induced the supercoiled form of the plasmid cleavage in the nicked and linear forms. Moreover, P(NVP-co-TrpAMT)-I exhibited stronger affinity for DNA than PVP and P(NVP-co-TrpAMT)-II (PVP/PTrpAMT molar ratio of 100:6.35). This phenomenon is believed to be related to the structure of TrpAMT and the hydrophobic nature of the copolymer. P(NVP-co-TrpAMT)-II with higher hydrophobic segments creates a strong hydrophobic interaction and induces a steric barrier which hinders their complexation with DNA. The study reveals important information about the inner mechanisms involved in the interaction of the PVP copolymer with DNA, which aids in the design of novel efficient non-ionic gene carriers. Copyright (C) 2008 John Wiley & Sons, Ltd.

Summary: Novel block copolymers poly(N-vinylpyrrolidone)-block-poly[(tert-butoxy) carbonyl] tryptophanamido-N′-methacryl thiourea (PVP-b-PTAM-I, II and III) were synthesized by atom transfer radical polymerization (ATRP) in DMF using PVP-Cl as macroinitiator. The structures of the copolymers were characterized by UV-vis and GPC-MALLS. The results revealed that the copolymers with controlled molecular weight and relatively low polydispersity (PDI

A novel thermosensitive amphiphilic graft copolymer PNIPAAm-g-PCbzEA appending carbazole group was successfully designed and synthesized by the free radical copolymerization of N-isopropylacrylamide with hydrophobic precursor polymers of vinyl-functionalized poly(2-(N-carbazolyl)ethyl acrylate) (PCbzEA) in DMF. The PNIPAAm-g-PCbzEA copolymer was characterized by FTIR, 1H NMR, GPC analysis, UV–vis spectroscopy and fluorescence spectroscopy. The TEM observation shows that the graft copolymer may self-assemble into polymeric micelles exhibiting a nanospheric morphology within a narrow size range of 30–60 nm in aqueous solution. From the 1H NMR and FTIR analysis, the polymer micelles are composed of hydrophobic PCbzEA segments as the cores and the hydrophilic PNIPAAm segements as outer shells. The resulting micelles exhibited the temperature sensitivity with a lower critical solution temperature (LCST) of 31.5°C and a critical micelle concentration (CMC) of 12.9 mg/L in water. In the study of drug release, an “on–off” drug release profile was found in response to stepwise temperature changes between 20 and 40°C. The cytotoxicity assays for vero cells shows good biocompatibility of the graft copolymer in vitro. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008

A new monomeric fluorophore N-acryl-N'-(quinolin-8-yl)thiourea (AQT) was synthesized. Free radical copolymerization was carried out in order to prepare a water-soluble fluorescent copolymer, based on N-isopropylacrylamide. The fluorescent characteristic of the aqueous solutions of copolymers was investigated both in varied pH and in the presence of metal cations. The polymer- contained AQT was found to be a selective chemosensor for Ni, Pb, Co ions especially for Co ion. The obtained copolymers show thermo-sensitive lower critical solution temperature (LCST) ranging from 32.5 to 37.5°C with varied ratios of AQT, N, N-dimethylacrylamide and N-isopropylamide. Copyright © 2007 John Wiley & Sons, Ltd.

Amphiphilic fluorescent graft copolymer (PVP-PyATAm) was successfully synthesized by the free radical copolymerizations of hydrophobic monomer N-acryloyl-thioureylene-4-(1-pyrene)-butyryl amide (PyATAm) with hydrophilic precursor polymers of vinyl-functionalized poly (N-vinylpyrrolidone) (Acryloyl-PVP) in DMF. FT-IR, 1H NMR, TEM, gel permeation chromatography-multi-angle laser light scattering, UV-vis spectroscopy, viscometric measurement, and fluorescence spectroscopy were used to characterize this copolymer. The TEM observation showed that the copolymer PVP- PyATAm formed spherical micelles in an aqueous solution and the size of micelles was between 50 and 70 nm in diameter. The interaction of PVP-PyATAm copolymer and plasmid DNA was examined by agarose gel electrophoresis and TEM. Results indicated that the copolymer–DNA complexes were self-assembled and the size of complexes was between 90 and 120 nm in diameter. Cytotoxity studies using MTT colorimetric assays suggested good biocompatibility of PVP-PyATAm in vitro. These results suggested the potential of this graft copolymer as gene delivery carrier. Copyright © 2007 John Wiley & Sons, Ltd.