Environment-Friendly Preparation and Characterization of Multilayered Conductive PVP/Col/CS Composite Doped with Nanoparticles as Potential Nerve Guide Conduits

Tissue engineering constitutes the most promising method of severe peripheral nerve injuries treatment and is considered as an alternative to autografts. To provide appropriate conditions during recovery special biomaterials called nerve guide conduits are required. An ideal candidate for this purpose should not only be biocompatible and protect newly forming tissue but also promote the recovery process. In this article a novel, multilayered biomaterial based on polyvinylpyrrolidone, collagen and chitosan of gradient structure modified with conductive nanoparticles is presented. Products were obtained by the combination of electrospinning and electrospraying techniques. Nerve guide conduits were subjected to FT-IR analysis, morphology and elemental composition study using SEM/EDS as well as biodegradation. Furthermore, their effect on 1321N1 human cell line was investigated by long-term cell culture. Lack of cytotoxicity was confirmed by XTT assay and morphology study. Obtained results confirmed a high potential of newly developed biomaterials in the field of nerve tissue regeneration with a special focus on injured nerves recovery.

Versatile Polymer-Initiating Biomineralization for Tumor Blockade Therapy

Tumor blockade therapy is a promising penetration-independent antitumor modality, which effectively inhibits the exchange of nutrients, oxygen, and information between the tumor and surrounding microenvironments. However, the current blockade therapy strategies have limited antitumor efficacy due to defects of inadequate tumor obstruction, possible side effects, and short duration. For these reasons, a facilely synthesized versatile polymer 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-poly(ethylene glycol)-alendronate (DSPE-PEG-ALN, DPA) is developed to initiate the formation of biomineral shell around osteosarcoma as a potent physical barrier. The DSPE moiety shares a similar chemical structure with the cytomembrane, allowing the membrane insertion of DPA. The bisphosphonic acid groups in ALN attract ions to realize biomineralization around cells. After injection in the invasive osteosarcoma tissue, DPA inserts into the cytomembrane, induces continuous mineral deposition, and ultimately builds a physical barrier around the tumor. Meanwhile, ALN in DPA alleviates bone destruction by suppressing the activity of osteoclasts. Through hindering the exchange of necessary substances, the biomineralization coating inhibits the growth of primary osteosarcoma and pulmonary metastasis simultaneously. Therefore, the multifunctional polymer-initiating blockade therapy provides a promising modality for tumor inhibition in clinics with high efficacy and negligible side effects.

Polymers for Improved Delivery of Iodinated Contrast Agents

X-ray computed tomography (CT), as one of the most widely used noninvasive imaging modalities, can provide three-dimensional anatomic details with high resolution, which plays a key role in disease diagnosis and treatment assessment. However, although they are the most prevalent and FDA-approved contrast agents, iodinated water-soluble molecules still face some challenges in clinical applications, such as fast clearance, serious adverse effects, nonspecific distribution, and low sensitivity. Because of their high biocompatibility, tunable designability, controllable biodegradation, facile synthesis, and modification capability, the polymers have demonstrated great potential for efficient delivery of iodinated contrast agents (ICAs). Herein, we comprehensively summarized the applications of multifunctional polymeric materials for ICA delivery in terms of increasing circulation time, decreasing nephrotoxicity, and improving the specificity and sensitivity of ICAs for CT imaging. We mainly focused on various iodinated polymers from the aspects of preparation, functionalization, and application in medical diagnosis. Future perspectives for achieving better imaging and clinical translation are also discussed to motivate new technologies and solutions.

Versatile Multi-Functional Block Copolymers Made by Atom Transfer Radical Polymerization and Post-Synthetic Modification: Switching from Volatile Organic Compound Sensors to Polymeric Surfactants for Water Rheology Control via Hydrolysis

Novel, multipurpose terpolymers based on styrene (PS), tert-butyl methacrylate (tBMA) and glycidyl methacrylate (GMA), have been synthesized via Atom Transfer Radical Polymerization (ATRP). Post-synthetic modification with 1-pyrenemethylamine (AMP) allows non-covalent functionalization of carbon nanotubes, eventually yielding a conductive nanocomposite materials capable of interacting with different Volatile Organic Compounds (VOCs) by electrical resistance variation upon exposure. Moreover, facile hydrolysis of the tBMA group yields polyelectrolytic macrosurfactants with remarkable thickening properties for promising applications in water solution, such as Enhanced Oil Recovery (EOR).

Polymer-grafted QCM chemical sensor and application to heavy metalions real time detection

A flow type quartz crystal microbalance (QCM) chemical sensor was developed for monitoring of heavy metal ions in aqueous solutions (that is suitable for environmental monitoring). The sensor is based upon surface chelation of the metal ions at multifunctional polymer modified gold electrodes on 9 MHz AT-cut quartz resonators, functioning as a QCM. New processes have been developed which enable to obtain surface-modified gold electrodes with high heavy metal ions complexing ability. These polymer grafted QCM sensors can selectively adsorb heavy metal ions, such as copper lead chrome and cadmium, from solution over a wide range from 0.01 to 1000 ppm concentration by complexation with functional groups in the polymers. Cations typically present in natural water did not interfere with the detection of heavy metals. X-Ray Reflectivity (XRR) and Total Reflection X-ray Fluorescence (TXRF) were carried out to characterise the unmodified and modified gold surfaces as well as to verify the possibility to selectively bond and remove metal ions.