Si-based Hybrid (Bio)materials
The subgroup dealing with the broadly understood chemistry of silicon compounds is coordinated by Dr. Łukasz John. This subject is implemented as part of several projects, among others financed by National Science Centre and Ministry of Science and Higher Education programs. Currently ongoing research projects concern: Constructing Covalent Organic-Inorganic Frameworks and Non-Covalent Supramolecular Networks Based on Functionalized Cage-like Silsesquioxanes Towards Novel Class of Porous Materials (Grant No. 2016/23/B/ST5/01480) and Three-Dimensional Hybrid Biomaterials Doped with Magnetic Nanoparticles for Thermal Apoptosis of Cancer Cells and Attached Growth Factor for Osteoblasts (Grant No. 2013/09/D/ST8/03995). We encourage you to read selected summaries of our representative publications in these fields. We also invite you to cooperate with our group. We would like to invite researchers around the world to be in touch. If you have any questions, please send us e-mail: lukasz.john@chem.uni.wroc.pl.
Strontium-Doped Organic-Inorganic Hybrids Towards Three-Dimensional Scaffolds for Osteogenic Cells
Biomimetic organic–inorganic hybrid bioscaffolds are developed to complement or replace damaged fragments in bone tissue surgery. The aim of this work was to develop a simple and fast method to prepare composite material for bone engineering, avoiding time consuming and complex methodologies. The resulting materials (also called in this work as hybrid composites or hybrid scaffolds) have a three-dimensional macroporous polymer-like network derived from triethoxyvinylsilane (TEVS) and 2-hydroxyethylmethacrylate (HEMA) monomers, with incorporated calcium, strontium, and phosphate ions. The materials were fully characterized using FT-IR, biomineralization studies, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, scratch tests, Young’s modulus and compressive strength tests, and gas physisorption. We report a comprehensive study on the in vitro effect of novel strontium doped materials on human bone cells. In vitro investigations were conducted using a normal human osteoblast cell line that mimics the cellular events of the in vivo intramembranous bone formation process. The materials do not have a negative impact on the survival of the normal human osteoblasts; moreover, materials doped with strontium show that not only are cells able to survive, but they also attach to and grow on a bioscaffolds surface. For this reason, they may be used in future in vivo experiments.
For details see: Mater. Sci. Eng. C 2016, 68, 117-127
Project was realized in cooperation with our colleagues from Wrocław Medical University (Professor Piotr Dzięgiel).
Designing of Macroporous Magnetic Bioscaffolds Based on Functionalized Methacrylate Network Covered by Hydroxyapatites and Doped with Nano-MgFe2O4 for Potential Cancer Hyperthermia Therapy
In this paper, we report on synthesis and characterization of three-dimensional biocomposite based on a polymerized 3-(trimethoxysilyl)propyl methacrylate/ethylene glycol dimethacrylate (pTMSPMA/pEGDMA) framework. The resulting composite was doped with Ca2+ and PO43– or decorated by hydroxyapatite (HA) and carbonate hydroxyapatite (CHA) to aid potential bone fixation and the in vitro bioactivity was evaluated. During the construction of the macroporous scaffold, the size and shape of pores were modified depending on the type of porogens which was applied (commercially available sugar, NaCl, or NH4Cl). Delivered 3D biomaterial was next used in preparation of a magnetic scaffold containing the core/shell magnetic nanoparticles covered with silicon-rich layer creating the amorphous magnetic dead layer. Preliminary magnetic studies showed that nanocrystalline MgFe2O4@SiO2 possesses a superparamagnetic properties, narrow hysteresis loop and virgin curve. The developed magnetic scaffold fulfills the requirements of a promising biomaterial for potential cancer hyperthermia therapy.
For details see: Mater. Sci. Eng. C 2017, 78, 901-911
Synthesis and Microstructural Properties of the Scaffold Based on 3-(Trimethoxysilyl)propyl Methacrylate-POSS Hybrid Towards Potential Tissue Engineering Applications
The aim of this work was to develop an efficient approach to prepare a macroporous scaffold for sophisticated bone replacement, avoiding a long-lasting and complex methodology. Such a scaffold based on the 3-(trimethoxysilyl)propyl methacrylate-POSS hybrid was synthesized via reaction of 3-(trimethoxysilyl)propyl methacrylate and the trifluoromethanesulfonate-POSS salt. The results show that the chemical composition, structural dimensions, topography, and microstructural properties of the scaffold fulfill the potential requirements for hard-tissue engineering. The microsturctural properties were evaluated with the use of X-ray microcomputed tomography (micro-CT) and nanoidentation tests. The former makes it possible to estimate the geometrical measures of the microstructure (porosity, thickness distribution, etc.), whereas the latter makes it possible to estimate the mechanical properties of the constituents of the material (hardness, stiffness modulus, creep, etc.). The aforementioned laboratory testing methods are modern techniques, currently being developed for materials science, making it possible to determine the microstructural/measures of the analyzed system.
For details see: RSC Adv. 2016, 6, 66037-66047
Project was realized in cooperation with our collegues from Wrocław University of Science and Technology (Professor Dr. Dariusz Łydżba)
Synthesis of Cubic Spherosilicates for Self-Assembled Organic-Inorganic Biohybrids Based on Functionalized Methacrylates
The aim of this work is to develop an efficient synthetic approach to hexahedral cage-like organic–inorganic siloxane core biohybrids containing side chains fully functionalized by methacrylate groups derived from monomers such as 2-hydroxyethyl methacrylate (HEMA) or ethylene glycol dimethacrylate (EGDMA). The resulting hybrids were characterized using spectroscopic methods (FTIR, 1H, 13C, 29Si NMR), thermogravimetric and DSC analyses, and high resolution mass spectrometry (HR-MS). The obtained compounds, after polycondensation/polymerization reactions, were utilized in constructing 3D macroporous scaffolds which were examined using a scanning electron microscope (SEM). Covalent networks created by fully functionalized cubic spherosilicates can mimic certain biomaterials and constitute sophisticated, highly organized building blocks of complex systems.
Back Cover Page - New Journal of Chemistry
For details see: New. J. Chem. 2018, 42, 39-47
Imaging Physicochemical Reactions Occuring at the Pore Surface in Binary Bioactive Glass Foams by Micro Ion Beam Analysis
In this work, the physicochemical reactions occurring at the surface of bioactive sol-gel derived 3D glass scaffolds via a complete PIXE characterization were studied. 3D glass foams in the SiO2-CaO system were prepared by sol-gel route. Samples of glass scaffolds were soaked in biological fluids for periods up to 2 days. The surface changes were characterized using particle induced X-ray emission (PIXE) associated to Rutherford backscattering spectroscopy (RBS), which are efficient methods to perform quantitative chemical maps. Elemental maps of major and trace elements at the glass/biological fluids interface were obtained at the micrometer scale for every interaction time. Results revealed interconnected macropores and physicochemical reactions occurring at the surface of pores. The micro-PIXE-RBS characterization of the pores/biological fluids interface shows the glass dissolution and the rapid formation of a Ca rich layer with the presence of phosphorus that came from biological fluids. After 2 days, a calcium phosphate-rich layer containing magnesium is formed at the surface of the glass scaffolds. We demonstrate that quantities of phosphorus provided only by the biological medium have a significant impact on the development and the formation of the phosphocalcic layer.
For details see: ACS Appl. Mater. Interfaces 2010, 2, 1737-1742
Project was realized in cooperation of our colleagues from Blaise Pascal University, Clermont-Ferrand, France (Professor Jean-Marie Nedelec and Professor Edouard Jallot).
Selected Developments and Medical Applications of Organic-Inorganic Hybrid Biomaterials Based on Functionalized Spherosilicates
Well–defined and tailor–made spherosilicates and POSS–based (nano)composites with interesting chemical and mechanical properties have applications in a widely regarded innovative biomaterials. They can serve as delivery systems, three–dimensional scaffolds for specific tissue engineering, biomaterials for orthopedic, cardiovascular, and reconstructive surgery, etc. Such organic–inorganic hybrids are much more effective biomaterials than pure polymers, bioglasses, metals, alloys, and ceramics currently used in medical applications and are considered as a next–generation systems in innovative medical approaches. This range of applications creates a strong impetus for novel, cheap, and easy–to–scale–up methods for their synthesis. In this review (highlights since 2006), selected biomaterials consisting various polymeric derivatives such as polymethacrylates, polylactides, polycaprolactones, polyurethanes, etc. which serve as organic side arms of POSS and can create polymer platform for precisely localized spherosilicates among organic matrices are discussed as a new generation of silicon–based biosystems using spherosilicates, a promising biomaterials with particular use in soft and hard tissue engineering.
For details see: Mater. Sci. Eng. C For details see: Mater. Sci. Eng. C 2018, 88, 172-181
High-Yield Synthesis of Amido-Functionalized Polyoctahedral Oligomeric Silsesquioxanes by Using Acyl Chlorides
Homosubstituted amido-functionalized polyoctahedral oligomeric silsesquioxanes (POSS) have been synthesized by using acyl chlorides in high yields (ca. 95%). The method proved to be superior over “conventional” syntheses applying carboxylic acids or acid anhydrides, which are much less efficient (ca. 60% yield). A palette of aryl and alkyl groups has been used as side-chains. The structures of the resulting amide-POSS are supported by multinuclear 1H, 13C, 29Si NMR and FTIR spectroscopy and their full conversion into octasubstituted derivatives was confirmed using mass spectrometry. We also demonstrate that the functionalized silsesquioxanes with bulky organic side-chains attached to cubic siloxane core form spherical-like, well-separated nanoparticles with a size of approximately 5 nm.
For details see: Chem. Eur. J. 2014, 20, 15966-15974
Novel Organic-Inorganic Hybrids Based on T8 and T10 Silsesquioxanes: Synthesis, Cage-Rearrangement and Properties
In this paper, we present a simple approach for the synthesis of well-defined macromolecules based on precisely isolated amino- and amido-functionalized octa T8 and deca T10 silsesquioxanes (SQs). Here, we show that reorganization of the siloxane cage-like core (T8 / T10) can be easily performed, including isolation of intermediates, and cage rearrangement achieved by using Brønsted superacid, trifluoromethanesulfonic acid (CF3SO3H). Moreover, T10-like SQs can be obtained in a one-step reaction by alkoxysilane condensation in trifluoromethanesulfonic acid conditions. The resulting decamers of amine-SQ and an amido-functionalized derivative containing long alkyl chains are reported for the first time in the literature. The non-fluorinated amido derivatives due to their lamellar-like nature and specific packing can serve as transparent hydrophobic coatings in various industrial applications. The obtained compounds were fully characterized using FT-IR, UV-vis, multinuclear NMR (1H, 13C, 29Si), DOSY NMR, TG-DTA, DSC, HR-MS, TEM, EDS and elemental analysis.
For details see: RSC Adv. 2015, 5, 72340-72351
First Step Towards a Model System of the Drug Delivery Network Based on Amide-POSS Nanocarriers
Among the varied and diverse family of drug delivery systems (DDSs), such as polymer–drug conjugates, polymeric micelles, dendrimers and molecular containers, polyhedral oligomeric silsesquioxanes (POSS) occupy a special position within the group of biocompatible drug carriers. The extraordinary recommendation of POSS for such systems derives from their three-dimensional structure, nanoscale size, low toxicity, and efficient cellular uptake. These conjugates can be strictly designed compared for instance to micelles, dendrimeric-drug or polymer/inorganic hybrid composites, in which the amount of therapeutics attached to the carrier is rather random, and there is a high probability that some of the drug molecules can be completely trapped inside the ramified structures. The combination of fully functionalized amide-POSS and pharmaceuticals might create a so-called sophisticated DDS. In such a system, the adsorbed drug molecules can be released under physiological conditions and then the POSS-based carrier will be hydrolyzed (at pH = 7.40) to a non-toxic carboxylic acid salt and a water soluble polyhedral oligomeric silsesquioxane containing an aminopropyl group that can be safely removed from the organism.
For details see: RSC Adv. 2017, 7, 8394-8401
Multifunctional Imine-POSS as Uncommon 3D Nanobuilding Blocks for Supramolecular Hybrid Materials: Synthesis, Structural Characterization, and Properties
In this article, we report on the chemistry and the spectroscopic properties of well-defined iminofunctionalized polyoctahedral oligomeric silsesquioxanes (imine-POSS) with various substitutions. Our efforts were mainly focused on side chains with sizable aryl groups possessing hydroxyl, nitro, and halide moieties. Such a choice enabled us to track their reduction abilities to secondary amine-POSS, tautomerization effects, and thermal properties. We also report for the first time the solid-state structures of five imino-functionalized cage-like octasilsesquioxanes. These structures provide unique examples of the complexities of three-dimensional packing motifs and their relationship with the assembly of tunable materials from nanobuilding blocks.
Front Cover Page - Dalton Transactions
For details see: Dalton Trans. 2016, 45, 12312-12321