Key Engineering Materials Vol. 850

Abstract: Fucus Vesiculosus (F. Vesiculosus) by its composition is a unique raw for obtaining of variety substances with a wide range of consumer properties. The composition of the polyphenolic fraction of F. Vesiculosus is characterized by a predominant content of phloroglucinol polymers - phlorotannins, which are the target compound of this study. Microwave assisted pre-treatments of algae were carried out in order to intensify the extraction of target compound. The pre-treatment efficiency was evaluated by determining the yield of extractives, polyphenols and phlorotannins. The chemical composition of the polyphenols fraction of algae was studied. The obtained results show that microwave treatment of F. Vesiculosus allows to increase 1.6 times the yield of target compound with lower energy consumption compared to the reference sample. The obtaining extracts obtained have a high antibacterial effect on gram-positive and gram-negative bacteria, and also stimulate the growth of pea seedlings and can be recommended for use in agriculture as a growth stimulator in preparing seeds for sowing and also as an antibacterial agent, protecting as seeds and seedlings from pathogenic bacteria.

Abstract: The aim of this study is to summarize various synthesis routes of amorphous calcium phosphate (ACP), focusing on properties, especially Ca/P molar ratio and specific surface area (SSA) of obtained ACP. The effects of synthesis conditions on properties of final products are analysed and discussed.

Abstract: Already validated methodology for self-association in solutions were used to evaluate if this method could also be used in other studies regarding association in solution. Three isomeric dihydroxybenzoic acids were used to calculate Gibbs free energies of association for homodimers, heterotetramers and associates with solvent molecules by using DFT calculations in multiple environments and having different conformations.

Abstract: Site specific drug delivery systems (DDS) are usually developed to overcome the side effects of conventional ones (e.g. injections or oral ingestions), creating smart drug delivery vehicles characterized with greater efficiency, safety, predictable therapeutic response as well as controlled and prolonged drug release periods. DDS made of hyaluronic acid (HA) and poly-L-lysine (PLL) are promising candidates in the field of local drug delivery due to their high biocompatibility. Moreover, electrostatic attractions between negatively charged HA and positively charged PLL can be used to fabricate multilayer films, bilayer films and hydrogels, avoiding the application of toxic crosslinking agents. In this review, we report the preparation of HA/PLL composites exploiting their intrinsic properties, as well as developed composite application possibilities as controlled drug delivery systems in bone tissue, central nervous system and gene engineering.

Abstract: Two isothiocyanates, i.e., sulforaphane (SFA) and sulforaphene (SFE), are suggested to be used as an alternative chemopreventive diet. This study was focused on the effect of SFA and SFE on Lactobacillus plantarum, which has been subjected to the irradiation (2-50 Gy). The cultures grown in De Man, Rogosa and Sharpe (MRS) and Tryptone Soya Broth (TSB) were compared in terms of bacteria physiological activity under tested conditions. Broth composition notably influenced the bacteria growth kinetic parameters, as well as culture response to the oxidative stress. Activity of L. plantarum cells after irradiation was evaluated by their dehydrogenase (DHA) and quinone-reductase (QR) activities. The enzyme activity was quantified in living cells. Bacterial cultures obtained in MRS and TSB broth, demonstrated contrasting characteristics in their enzyme activities. The MRS-grown culture did not show any QR activity, whereas the TSB-grown cells showed a non-linear response towards gamma-irradiation with a maximum inhibition being at 10 Gy. Addition of SFA or SFE in concentration of 1 µg/mL to the cultures before irradiation exposure recovered the QR activity from 23% in a non-amended variant up to 102% and 121%, respectively, taking the non-irradiated non-amended variant as 100%.

Abstract: A simple solution for fulfilling biosafety and national drug agency demands of radiation and biosafety during Ga-68 radionuclide containing radiopharmaceutical production (RP) by small scale laboratories has been demonstrated based on a novel sterile seal concept of multi-layer bag system prototype. These mid-and inner enclosures of the prototype with vial inside were sterilized by 50 kGy of gamma radiation. The microbial safety validation based on two-week testing confirmed successful sterilization of the sealing bags with vails. The analysis of physicochemical properties, namely mechanical properties, gel fraction studies revealed that sterilization did not cause any undesired changes in developed materials, compared to non-irradiated control samples.

Abstract: The most common cinnamoyl anilines are avenanthramides, which are natural antioxidants found in oats. This is a rather uncommon and not well-investigated group of antioxidants. This paper deals with 2-arylidenemalonic acid dianilides – cinnamoyl anilines which are decorated with an additional arylaminocarbonyl moiety at α-position of double bond. The DPPH scavenging activity of the title compounds is slightly lower in comparison to the corresponding cinnamoyl anilines. On the other hand, the title dianilides are more active than cinnamic acid anilides containing an additional carboxylic group in the α-position of double bond.

Abstract: Silk fibroin can be derived from the silkworm Bombyx mori and it has the main properties for its use as bioadhesive biomaterial in medicine – biocompatibility, good mechanical properties and controllable degradation rate. On the other hand hyaluronic acid (HA) is an attractive polymer for biomedical applications, due to its biological and structural importance, as well as its ease of modification. Thus in this study, two types of silk raw materials for preparation of silk fibroin (SF) solutions were used. Obtained SF solutions with and without hyaluronic acid (HA) were cross-linked to form hydrogels. Widely used cross-linking agent glutaraldehyde (GTA) was used in this study. Two temperatures 37°C and 60°C were chosen to determine the effect of temperature on the cross-linking rate of the samples. The gelation time, swelling ratio and structural features of the adhesive were also studied.

Abstract: At this work hydrogel and composite hydrogel systems based on ԑ-polylysine (EPL), hyaluronic acid (HA) and nanocrystalline hydroxyapatite (nHAp) were synthesized via chemical cross-linking method followed by in situ precipitation of nHAp into hydrogel copolymer matrix. Molecular structure, phase composition and morphology of EPL-HA and EPL-HA/nHAp systems were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray powder diffractometry (XRD) and scanning electron microscopy (SEM). The fabricated hydrogels and composite hydrogels were evaluated by hydrogels characteristics such as gel fraction and swelling behavior. This study provides a new insight to develop cutting-edge bioactive hydrogels and composite hydrogels for bone tissue engineering as injectable biomaterials due to beneficial properties of system components.

Abstract: The histomorphometry of the rabbit bone tissue from the lower jaw was done. Authors hypothesized that local enhancement with biphasic calcium phosphate ceramic materials in the femur trochanter major area increase the trabecular bone volume outside the implantation zone in vivo. Twenty-two California female rabbits were included in this study and were divided into four groups. Four healthy rabbits composed a control group (A group), while other eighteen underwent ovariectomy. Bone defects were created in femur trochanter major region. Sham surgery group (B group) consisted of four female rabbits with osteoporosis and bone defect, but no biomaterials were implanted. In C group (seven rabbits) created defects were filled with granules of biphasic calcium phosphate ceramic (hydroxyapatite (HAP) and tricalcium phosphate (TCP) 30/70); in D group (seven rabbits) defects were filled with the same granules (HAP/TCP 30/70) together with strontium (5% by mass). Twenty-two bone samples were taken from lower jaw premolar region. Trabecular bone area was measured using Image Pro Plus 7 program, where three equal fields (0.975 mm²) of view were at random chosen in all bone samples. Results have shown that the trabecular bone area in A group was 0.201 mm² (0.176-0.233), which is statistically significantly higher (p <0.0001) than in B group 0.127 mm² (0.118 – 0.149), C group 0.136 mm² (0.108 – 0.166) and D group 0.135 mm² (0.126 – 0.164), respectively. Statistically significant differences between B, C and D groups were not found (p > 0.05).