Graphene-based biomimetic materials targeting urine metabolite as potential cancer biomarker: Application over different conductive materials for potentiometric transduction

This work presents a novel surface Smart Polymer Antibody Material (SPAM) for Carnitine (CRT, a potential biomarker of ovarian cancer), tested for the first time as ionophore in potentiometric electrodes of unconventional configuration. The SPAM material consisted of a 3D polymeric network created by surface imprinting on graphene layers. The polymer was obtained by radical polymerization of (vinylbenzyl) trimethylammonium chloride and 4-styrenesulfonic acid (signaling the binding sites), and vinyl pivalate and ethylene glycol dimethacrylate (surroundings). Non-imprinted material (NIM) was prepared as control, by excluding the template from the procedure. These materials were then used to produce several plasticized PVC membranes, testing the relevance of including the SPAM as ionophore, and the need for a charged lipophilic additive. The membranes were casted over solid conductive supports of graphite or ITO/FTO. The effect of pH upon the potentiometric response was evaluated for different pHs (2-9) with different buffer compositions. Overall, the best performance was achieved for membranes with SPAM ionophore, having a cationic lipophilic additive and tested in HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) buffer, pH 5.1. Better slopes were achieved when the membrane was casted on conductive glass (-57.4 mV/decade), while the best detection limits were obtained for graphite-based conductive supports (3.6 × 10−5mol/L). Good selectivity was observed against BSA, ascorbic acid, glucose, creatinine and urea, tested for concentrations up to their normal physiologic levels in urine. The application of the devices to the analysis of spiked samples showed recoveries ranging from 91% (± 6.8%) to 118% (± 11.2%). Overall, the combination of the SPAM sensory material with a suitable selective membrane composition and electrode design has lead to a promising tool for point-of-care applications.

Biomimetic Materials for Biomedical Applications

Objects with complex shape and functions have always attracted attention and interest. The morphological diversity and complexity of naturally occurring forms and patterns have been a motivation for humans to copy and adopt ideas from Nature to achieve functional, aesthetic and social value. Biomimetics is addressed to the design and development of new synthetic materials using strategies adopted by living organisms to produce biological materials. In particular, biomineralized tissues are often sophisticate composite materials, in which the components and the interfaces between them have been defined and optimized, and that present unusual and optimal chemical-physical, morphological and mechanical properties. Moreover, biominerals are generally produced by easily traceable raw materials, in aqueous media and at room pressure and temperature, that is through cheap process and materials. Thus, it is not surprising that the idea to mimic those strategies proper of Nature has been employed in several areas of applied sciences, such as for the preparation of liquid crystals, ceramic thin films computer switches and many other advanced materials. On this basis, this PhD thesis is focused on the investigation of the interaction of biologically active ions and molecules with calcium phosphates with the aim to develop new materials for the substitution and repair of skeletal tissue, according to the following lines: I. Modified calcium phosphates. A relevant part of this PhD thesis has been addressed to study the interaction of Strontium with calcium phosphates. It was demonstrated that strontium ion can substitute for calcium into hydroxyapatite, causing appreciable structural and morphological modifications. The detailed structural analysis carried out on the nanocrystals at different strontium content provided new insight into its interaction with the structure of hydroxyapatite. At variance with the behaviour of Sr towards HA, it was found that this ion inhibits the synthesis of octacalcium phosphate. However, it can substitute for calcium in this structure up to 15 atom %, in agreement with the increase of the cell parameters observed on increasing ion concentration. A similar behaviour was found for Magnesium ion, whereas Manganese inhibits the synthesis of octacalcium phosphate and it promotes the precipitation of dicalcium phosphate dehydrate. It was also found that Strontium affects the kinetics of the reaction of hydrolysis of α-TCP. It inhibits the conversion from α-TCP to hydroxyapatite. However, the resulting apatitic phase contains significant amounts of Sr2+ suggesting that the addition of Sr2+ to the composition of α-TCP bone cements could be successfully exploited for its local delivery in bone defects. The hydrolysis of α-TCP has been investigated also in the presence of increasing amounts of gelatin: the results indicated that this biopolymer accelerates the hydrolysis reaction and promotes the conversion of α-TCP into OCP, suggesting that its addition in the composition of calcium phosphate cements can be employed to modulate the OCP/HA ratio, and as a consequence the solubility, of the set cement. II. Deposition of modified calcium phosphates on metallic substrates. Coating with a thin film of calcium phosphates is frequently applied on the surface of metallic implants in order to combine the high mechanical strength of the metal with the excellent bioactivity of the calcium phosphates surface layers. During this PhD thesis, thank to the collaboration with prof. I.N. Mihailescu, head of the Laser-Surface-Plasma Interactions Laboratory (National Institute for Lasers, Plasma and Radiation Physics – Laser Department, Bucharest) Pulsed Laser Deposition has been successfully applied to deposit thin films of Sr substituted HA on Titanium substrates. The synthesized coatings displayed a uniform Sr distribution, a granular surface and a good degree of crystallinity which slightly decreased on increasing Sr content. The results of in vitro tests carried out on osteoblast-like and osteoclast cells suggested that the presence of Sr in HA thin films can enhance the positive effect of HA coatings on osteointegration and bone regeneration, and prevent undesirable bone resorption. The possibility to introduce an active molecule in the implant site was explored using Matrix Assisted Pulsed Laser Evaporation to deposit hydroxyapatite nanocrystals at different content of alendronate, a bisphosphonate widely employed in the treatments of pathological diseases associated to bone loss. The coatings displayed a good degree of crystallinity, and the results of in vitro tests indicated that alendronate promotes proliferation and differentiation of osteoblasts even when incorporated into hydroxyapatite. III. Synthesis of drug carriers with a delayed release modulated by a calcium phosphate coating. A core-shell system for modulated drug delivery and release has been developed through optimization of the experimental conditions to cover gelatin microspheres with a uniform layer of calcium phosphate. The kinetics of the release from uncoated and coated microspheres was investigated using aspirin as a model drug. It was shown that the presence of the calcium phosphate shell delays the release of aspirin and allows to modulate its action.

A new biomimetic sensor for detecting carnitine, a potential biomarker in ovarian cancer

1st ASPIC International Congress

Development of biomimetic microengineered hydrogel fibers for tendon regeneration

Musculoskeletal diseases are one of the leading causes of disability worldwide. Tendon injuries are responsible for substantial morbidity, pain and disability. Tissue engineering strategies aim at translating tendon structure into biomimetic materials. The main goal of the present study is to develop microengineered hydrogel fibers through the combination of microfabrication and chemical interactions between oppositely charged polyelectrolytes. For this, methacrylated hyaluronic acid (MeHA) and chondroitin sulfate (MeCS) were combined with chitosan (CHT). Hydrogel fibers were obtained by injecting polymer solutions (either MeHA or MeHA/MeCS and CHT) in separate microchannels that join at a y-junction, with the materials interacting upon contact at the interface. To evaluate cell behavior, human tendon derived cells (hTDCs) were isolated from tendon surplus samples during orthopedic surgeries and seeded on top of the fibers. hTDCs adhered to the surface of the fibers, remaining viable, and were found to be expressing CD44, the receptor for hyaluronic acid. The synthesis of hydrogel fibers crosslinkable through both physical and chemical mechanisms combined with microfabrication technology allows the development of biomimetic structures with parallel fibers being formed towards the replication of tendon tissue architecture.

Biomimetic strategies to engineer mineralised human tissues

In the last few years, many reports have been describing promising biocompatible and biodegradable materials that can mimic in a certain extent the multidimensional hierarchical structure of bone, while are also capable of releasing bioactive agents or drugs in a controlled manner. Despite these great advances, new developments in the design and fabrication technologies are required to address the need to engineer suitable biomimetic materials in order tune cells functions, i.e. enhance cell-biomaterial interactions, and promote cell adhesion, proliferation, and differentiation ability. Scaffolds, hydrogels, fibres and composite materials are the most commonly used as biomimetics for bone tissue engineering. Dynamic systems such as bioreactors have also been attracting great deal of attention as it allows developing a wide range of novel in vitro strategies for the homogeneous coating of scaffolds and prosthesis with ceramics, and production of biomimetic constructs, prior its implantation in the body. Herein, it is overviewed the biomimetic strategies for bone tissue engineering, recent developments and future trends. Conventional and more recent processing methodologies are also described.

Materials Collection Creation and Administration: A New Role for Libraries (White Paper)

The Problem/Opportunity: To define, identify, and guide design-based materials collections in academic settings and foster community among those with existing collections and/or those considering creating and supporting one. Contents and topics: What is a materials collection? Why have a materials collection? Acquisition strategies Organizational approaches Programming possibilities Symposium summary Resources

Materials Education and Research in Art and Design: A New Role for Libraries - Session 3. RISD Faculty

Faculty from Rhode Island School of Design representing Interior Architecture, Industrial Design, and Textiles detail their thoughtful interactions with materials.

Materials Education and Research in Art and Design: A New Role for Libraries - Session 4. Designers

Designers respond to issues and synthesize ideas from throughout the day as voices from the field who directly encounter the need for recently graduated students to possess the ability to investigate and interrogate materials.

Materials Education and Research in Art and Design: A New Role for Libraries - Session 2. Educators

Educators representing interactions with materials speak to critical approaches, life-cycle concerns, critical thinking of composition/process/properties.

Polar Nature of Biomimetic Fluorapatite/Gelatin Composites: A Comparison of Bipolar Objects and the Polar State of Natural Tissue

The correspondence of the state of alignment of macromolecules in biomimetic materials and natural tissues is demonstrated by investigating a mechanism of electrical polarity formation: An in vitro grown biomimetic FAp/gelatin composite is investigated for its polar properties by second harmonic (SHGM) and scanning pyroelectric microscopy (SPEM). Hexagonal prismatic seed crystals formed in gelatin gels represent a monodomain polar state, due to aligned mineralized gelatin molecules. Later growth stages, showing dumbbell morphologies, develop into a bipolar state because of surface recognition by gelatin functionality: A reversal of the polar alignment of macromolecules, thus, takes place close to that basal plane of the seed. In natural hard tissues (teeth and bone investigated by SPEM) and the biomimetic FAp/gelatin composite, we find a surprising analogy in view of growth-induced states of polarity: The development of polarity in vivo and in vitro can be explained by a Markov-type mechanism of molecular recognition during the attachment of macromolecules.

Polímeros biomiméticos em química analítica. Parte 1: preparo e aplicações de MIP (Molecularly Imprinted Polymers) em técnicas de extração e separação

MIPs are synthetic polymers that are used as biomimetic materials simulating the mechanism verified in natural entities such as antibodies and enzymes. Although MIPs have been successfully used as an outstanding tool for enhancing the selectivity or different analytical approaches, such as separation science and electrochemical and optical sensors, several parameters must be optimized during their synthesis. Therefore, the state-of-the-art of MIP production as well as the different polymerization methods are discussed. The potential selectivity of MIPs in the extraction and separation techniques focusing mainly on environmental, clinical and pharmaceutical samples as applications for analytical purposes is presented.