This paper investigates the effect of plasticizer structure on especially the printability and mechanical and thermal properties of poly(3-hydroxybutyrate)-poly(lactic acid)-plasticizer biodegradable blends. Three plasticizers, acetyl tris(2-ethylhexyl) citrate, tris(2-ethylhexyl) citrate, and poly(ethylene glycol)bis(2-ethylhexanoate), were first checked whether they were miscible with poly(3-hydroxybutyrate)-poly(lactic acid) (PHB-PLA) blends using a kneading machine. PHB-PLA-plasticizer blends of 60-25-15 (wt.%) were then prepared using a corotating meshing twin-screw extruder, and a single screw extruder was used for filament preparation for further three-dimensional (3D) fused deposition modeling (FDM) printing. These innovative eco-friendly PHB-PLA-plasticizer blends were created with a majority of PHB, and therefore, poor mechanical properties and thermal properties of neat PHB-PLA blends were improved by adding appropriate plasticizer. The plasticizer also influences the printability of blends, which was investigated, based on our new specific printability tests developed for the optimization of printing conditions (especially printing temperature). Three-dimensional printed test samples were used for heat deflection temperature measurements and Charpy and tensile-impact tests. Plasticizer migration was also investigated. The macrostructure of 3D printed samples was observed using an optical microscope to check the printing quality and printing conditions. Tensile tests of 3D printed samples (dogbones), as well as extruded filaments, showed that measured elongation at break raised, from 21% for non-plasticized PHB-PLA reference blends to 84% for some plasticized blends in the form of filaments and from 10% (reference) to 32% for plasticized blends in the form of printed dogbones. Measurements of thermal properties (using modulated differential scanning calorimetry and oscillation rheometry) also confirmed the plasticizing effect on blends. The thermal and mechanical properties of PHB-PLA blends were improved by the addition of appropriate plasticizer. In contrast, the printability of the PHB-PLA reference seems to be slightly better than the printability of the plasticized blends.

This study is focused on thermoresponsive glycogen-graft-poly(2-alkyl-2-oxazolines), a new group of nanostructured hybrid dendrimeric stimuli-responsive polymers connecting the body's own biodegradable polysaccharidic dendrimer glycogen with the widely tuneable thermoresponsive behavior of polypeptide-analogic poly(2-alkyl-2-oxazolines), which are known to be biocompatible. Glycogengraft-poly(2-alkyl-2-oxazolines) were prepared by a simple one-pot two-step procedure involving cationic ring-opening polymerization of 2-alkyl-2-oxazolines followed by termination of the living cationic ends with sodium glycogenate. As confirmed by light and X-ray scattering, as well as cryotransmission electron microscopy, the grafted dendrimer structure allows easy adjustment of the cloud point temperature, the concentration dependence and nanostructure of the self-assembled phase separated polymer by crosstalk during graft composition, the graft length and the grafting density, in a very wide range.

We describe a new biopolymer-based nanofibrous material possibly suitable for tissue engineering prepared by an environment-friendly organic solvent-free method. Glycogen, a biodegradable hyperbranched D-glucose polymer, comes from renewable resources and is normally present in man. It forms nanofibres by simple freeze-drying from aqueous solutions with concentration less than 0.5%.However, the architecture of the freeze-dried material depends on the starting biopolymer concentration within the tested range 0.1-5 wt%; in particular higher concentrations produce porous sponge-like structures with communicating pores. Because of the solubility of glycogen in water, nanofibres were modified by solvent-free grafting biodegradable poly(ethyl cyanoacrylate) from vapor phase. Exposing glycogen nanofibres to vapors of ethyl cyanoacrylate only slightly changed the material architecture while producing a water-insoluble biodegradable material with glycogen-to-poly(ethyl cyanoacrylate) ratio depending on the polymerization time. The material was proven to be hydrolytically degradable over the course of several months.

A novel model of biodegradable PHA copolymer films preparation was applied to evaluate the biodegradability of various PHA copolymers and to discuss its biomedical applicability. In this study, we illustrate the potential biomaterial degradation rate affectability by manipulation of monomer composition via controlling the biosynthetic strategies. Within the experimental investigation, we have prepared two different copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate—P(3HB-co-36 mol.% 4HB) and P(3HB-co-66 mol.% 4HB), by cultivating the thermophilic bacterial strain Aneurinibacillus sp. H1 and further investigated its degradability in simulated body fluids (SBFs). Both copolymers revealed faster weight reduction in synthetic gastric juice (SGJ) and artificial colonic fluid (ACF) than simple homopolymer P3HB. In addition, degradation mechanisms differed across tested polymers, according to SEM micrographs. While incubated in SGJ, samples were fragmented due to fast hydrolysis sourcing from substantially low pH, which suggest abiotic degradation as the major degradation mechanism. On the contrary, ACF incubation indicated obvious enzymatic hydrolysis. Further, no cytotoxicity of the waste fluids was observed on CaCO-2 cell line. Based on these results in combination with high production flexibility, we suggest P(3HB-co-4HB) copolymers produced by Aneurinibacillus sp. H1 as being very auspicious polymers for intestinal in vivo treatments.

Two macrocyclic ligands based on cyclam with trans-disposed N-methyl and N-(4-aminobenzyl) substituents as well as two methylphosphinic (H2L1) or methylphosphonic (H4L2) acid pendant arms were synthesised and investigated in solution. The ligands form stable complexes with transition metal ions. Both ligands show high thermodynamic selectivity for divalent copper over nickel(II) and zinc(II)-K(CuL) is larger than K(Ni/ZnL) by about seven orders of magnitude. Complexation is significantly faster for the phosphonate ligand H4L2, probably due to the stronger coordination ability of the more basic phosphonate groups, which efficiently bind the metal ion in an "out-of-cage" complex and thus accelerate its "in-cage" binding. The rate of Cu(II) complexation by the phosphinate ligand H2L1 is comparable to that of cyclam itself and its derivatives with non-coordinating substituents. Acid-assisted decomplexation of the copper(II) complexes is relatively fast (τ1/2 = 44 and 42 s in 1 M aq. HClO4 at 25 °C for H2L1 and H4L2, respectively). This combination of properties is convenient for selective copper removal/purification. Thus, the title ligands were employed in the preparation of ion-selective resins for radiocopper(II) separation. Glycidyl methacrylate copolymer beads were modified with the ligands through a diazotisation reaction. The separation ability of the modified polymers was tested with cold copper(II) and non-carrier-added (64)Cu in the presence of a large excess of both nickel(II) and zinc(II). The experiments exhibited high overall separation efficiency leading to 60-70% recovery of radiocopper with high selectivity over the other metal ions, which were originally present in 900-fold molar excess. The results showed that chelating resins with properly tuned selectivity of their complexing moieties can be employed for radiocopper separation.

To facilitate efficient drug delivery to tumor tissue, several nanomaterials have been designed, with combined diagnostic and therapeutic properties. In this work, we carried out fundamental in vitro and in vivo experiments to assess the labeling efficacy of our novel theranostic nanoprobe, consisting of glycogen conjugated with a red fluorescent probe and gadolinium. Microscopy and resazurin viability assays were used to study cell labeling and cell viability in human metastatic melanoma cell lines. Fluorescence lifetime correlation spectroscopy (FLCS) was done to investigate nanoprobe stability. Magnetic resonance imaging (MRI) was performed to study T1 relaxivity in vitro, and contrast enhancement in a subcutaneous in vivo tumor model. Efficient cell labeling was demonstrated, while cell viability, cell migration, and cell growth was not affected. FLCS showed that the nanoprobe did not degrade in blood plasma. MRI demonstrated that down to 750 cells/μL of labeled cells in agar phantoms could be detected. In vivo MRI showed that contrast enhancement in tumors was comparable between Omniscan contrast agent and the nanoprobe. In conclusion, we demonstrate for the first time that a non-toxic glycogen-based nanoprobe may effectively visualize tumor cells and tissue, and, in future experiments, we will investigate its therapeutic potential by conjugating therapeutic compounds to the nanoprobe.

The effective drug delivery systems for cancer treatment are currently on high demand. In this paper, biological behavior of the novel hybrid copolymers based on polysaccharide glycogen were characterized. The copolymers were modified by fluorescent dyes for flow cytometry, confocal microscopy, and in vivo fluorescence imaging. Moreover, the effect of oxazoline grafts on degradation rate was examined. Intracellular localization, cytotoxicity, and internalization route of the modified copolymers were examined on HepG2 cell line. Biodistribution of copolymers was addressed by in vivo fluorescence imaging in C57BL/6 mice. Our results indicate biocompatibility, biodegradability, and non-toxicity of the glycogen-based hybrid copolymers. Copolymers were endocyted into the cytoplasm, most probably via caveolae-mediated endocytosis. Higher content of oxazoline in polymers slowed down cellular uptake. No strong colocalization of the glycogen-based probe with lysosomes was observed; thus, it seems that the modified externally administered glycogen is degraded in the same way as an endogenous glycogen. In vivo experiment showed relatively fast biodistribution and biodegradation. In conclusion, this novel nanoprobe offers unique chemical and biological attributes for its use as a novel drug delivery system that might serve as an efficient carrier for cancer therapeutics with multimodal imaging properties.

A microfluidic sensor was studied for the photometric detection of active chlorine, total chlorine, and pH in swimming pool samples. The sensor consisted of a four-layer borosilicate glass chip, containing a microchannel network and a 2.2 mm path length, 1.7 mL optical cell. The chip was optimised to measure the bleaching of methyl orange and spectral changes in phenol red for quantitative chlorine (active and total) and pH measurements that were suited to swimming pool monitoring. Reagent consumption (60 mL per measurement) was minimised to allow for maintenance-free operation over a nominal summer season (3 months) with minimal waste. The chip was tested using samples from 12 domestic, public, and commercial swimming pools (indoor and outdoor), with results that compare favourably with commercial products (test strips and the N,N’-diethyl-p-phenylenediamine (DPD) method), precision pH electrodes, and iodometric titration.