Construction of Supramolecular Polymers with Different Topologies by Orthogonal Self-Assembly of Cryptand-Paraquat Recognition and Metal Coordination.

Recently, metal-coordinated orthogonal self-assembly has been used as a feasible and efficient method in the construction of polymeric materials, which can also provide supramolecular self-assembly complexes with different topologies. Herein, a cryptand with a rigid pyridyl group on the third arm derived from BMP32C10 was synthesized. Through coordination-driven self-assembly with a bidentate organoplatinum(II) acceptor or tetradentate Pd(BF4)2•4CH3CN, a di-cryptand complex and tetra-cryptand complex were prepared, respectively. Subsequently, through the addition of a di-paraquat guest, linear and cross-linked supramolecular polymers were constructed through orthogonal self-assembly, respectively. By comparing their proton nuclear magnetic resonance (1H NMR) and diffusion-ordered spectroscopy (DOSY) spectra, it was found that the degrees of polymerization were dependent not only on the concentrations of the monomers but also on the topologies of the supramolecular polymers.

Continuous Monitoring of Buried Free Bone Flap Microcirculation Using a Near-Infrared Spectroscopy System.

SUMMARY: Postoperative evaluation of free flaps remains a challenging task. The current accepted standard for diagnosis of vascular compromise remains clinical observation. In recent years, near-infrared spectroscopy (NIRS) has been widely used as a noninvasive objective monitoring tool for postoperative evaluation of soft-tissue flaps. However, methods for monitoring bone flaps remain inadequate. In this study, NIRS was applied for the first time to monitor free buried bone flaps that were used for mandibular reconstruction. The penetrating property of NIRS was used to measure the tissue oxygenation index (TOI) of deep tissues, which reflected the microcirculatory status of the tissues. Changes in TOI values were monitored continuously in 59 cases of free bone flaps up to 72 hours after surgery. Five cases of vascular compromise were noted by clinical observation. Two fibula flaps were total failures, one of which showed a sharp decrease in TOI value to 45% in a short period of time; the other showed a continual gradual decrease to 55%. The observed sudden (<50%) and continuous (>10%) decreases in TOI values suggest that more attention should be paid to revision surgical procedures. The authors conclude that NIRS holds promise as an objective and valid method for clinical evaluation of buried bone flaps.

Comparison of two kinds of magnetic nanoparticles in vivo and in vitro.

This study compared a new type of polysaccharide-coated magnetic nanoparticles (in which the polysaccharide is derived from Angelica sinensis) with the dextran magnetic nanoparticles in terms of preparation, biocompatibility and tissue distribution in vivo and in vitro in order to examine the potential application of Angelica polysaccharide as a novel carrier in magnetic drug targeting (MDT). Magnetic nanoparticles were prepared by chemical co-precipitation. Their physical and chemical properties were determined by using the transmission electron microscope (TEM), laser particle size analyzer (DLS) and vibrating sample magnetometer (VSM), and their purity and structure by using X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). The atomic absorption spectrometric method was performed for quantification of the iron content in different tissues. Histological sections were stained by Prussian blue staining to observe the disposition of magnetic nanoparticles in the liver and kidney. The results showed that both kinds of magnetic nanoparticles possessed small particle size, good dispersion and good magnetic properties. XRD showed the main component of the two magnetic nanoparticles was Fe(3)O(4) crystals, and FTIR proved Fe(3)O(4) was successfully coated by each polysaccharide, respectively. In vivo, Fe(3)O(4)-dextran accumulated in the liver, spleen and lung and Fe(3)O(4)-Angelica polysaccharide only in the spleen and lung. It was concluded that Angelica polysaccharide may be applied as a novel carrier in the preparation of magnetic nanoparticles.

Self-assembled NIR-II Fluorophores with Ultralong Blood Circulation for Cancer Imaging and Image-guided Surgery.

Complete excision of the last remaining 1-2% of tumor tissue without collateral damage remains particularly challenging. Herein, we report thiophenthiadiazole (TTD)-derived fluorophores L6-PEGnk (n = 1, 2, 5) as new-generation NIR-II (1000-1700 nm) probes with exceptional nonfouling performance and significantly high fluorescence quantum yields in water. L6-PEG2k can self-assemble into vesicular micelles and exhibited minimal immunogenicity, low binding affinities, ultralong blood circulation (t1/2 = 59.5 h), and a supercontrast ratio in vivo. Most importantly, L6-PEG2k achieved excellent in vivo CT-26 and U87MG tumor targeting and accumulation (>20 d) through intraperitoneal or intravenous injection. A subcutaneous U87MG tumor and orthotopic brain glioma were successfully resected under NIR-II FIGS in our animal model via intraperitoneal injection in an extended time window (48-144 h). This study highlights the potential of using L6-PEG2K as self-assembling molecular probes with long-circulation persistence for routine preoperative tumor assessment and precise intraoperative image-guided resection.

Determination of anti-tuberculosis drug concentration and distribution from sustained release microspheres in the vertebrae of a spinal tuberculosis rabbit model.

There have been several sustained-release materials containing anti-tuberculosis drug to enhance concentration in foci of spinal tuberculosis but what map by which composite drug delivery system is released is not known. Isoniazid (INH) lactic-co-glycolic acid (PLGA) and INH hydroxyapatite (HA) microspheres were prepared, respectively. The rabbits were modeled by tuberculosis strains and sustained-release microspheres were incubated in the foci. INH concentrations in the HA group were higher than those of INH and PLGA groups at L3, L4, and L5 vertebra 2 days after the drugs were embedded (p < 0.05). INH concentrations in the HA group were higher than those of INH and PLGA groups in L3 vertebra 4 days after the drugs were embedded (p < 0.05). INH concentrations in the PLGA group were higher than those of INH and HA groups in L5 vertebra; INH concentrations of the HA group were higher than those of INH and PLGA groups in L4 vertebra 6 days after the drugs were embedded (p < 0.05). These microspheres can enhance INH concentration in the foci. Furthermore, HA microspheres elicit osteogenic effects. HA is better than PLGA in terms of infiltration, but PLGA is better than HA in terms of distribution. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:200-208, 2017.

[Percutaneous vertebroplasty and kyphoplasty for the treatment of thoracolumbar fractures in the elderly].

OBJECTIVE: To study the clinical effects of percutaneous vertebroplasty and kyphoplasty in the treatment of fresh thoracolumbar fractures in the elderly. METHODS: From May 2004 to March 2009, among 29 patients (32 vertebras) with thoracolumbar fractures, 18 patients (21 vertebras) were treated with percutaneous vertebroplasty (PVP) and 11 patients (11 vertebras) were treated with percutaneous kyphoplasty (PKP). The visual analogue scale (VAS) and mobility were evaluated 3 days before and after operation. During follow-up period, patients were observed and evaluated in terms of relief of back pain and regaining of living ability. Complications such as bone cement leakage were analyzed. RESULTS: All the patients got successful operation. The average operation time was 38.6 minutes for the 18 patients (21 vertebras) with PVP performed, and 3.2 ml (2-5 ml) bone cement was injected. For the 11 patients (11 vertebras) with PKP performed, the average operation time was 43 minutes, and an average of 3.8 ml (2-6 ml) bone cement was injected. The VAS decreased from preoperative (7.5 +/- 0.7) to (2.2 +/- 0.5) at the 3rd day after operation; the mobility scores of the patients decreased from preoperative (2.4 +/- 0.6) to (1.2 +/- 0.3) at the 3rd day after operation; the vertebral height increased from an average of (52.4 +/- 9.7)% pre-operation to (85.2 +/- 10.6)% after operation; and the average kyphosis correction of Cobb angle was 11.2 degrees. During an average of 12.6 months follow-up, no patients reported vertebral pain. Review of X-ray films showed no significant loss of vertebral height. One patient died from complications of heart disease 5 months being discharged from hospital. Another patient died from the same cause at 6 months after opertaion. Paravertebral leakage of bone cement was also found in 2 patients. No serious complications occurred and patients were satisfied with the treatment. CONCLUSION: PVP, PKP can be used to instantly reinforce vertebral injury, relieve pain, and improve the patient's mobility. For elder people with fresh thoracolumbar fractures, when health conditions are allowed, PVP or PKP surgery is the right treatment.

Formation of linear main-chain polypseudorotaxanes with supramolecular polymer backbones via two self-sorting host-guest recognition motifs.

Based on two self-sorting host-guest recognition motifs, novel linear main-chain polypseudorotaxanes with supramolecular polymer backbones have been constructed from three components in solution at high concentrations.