Biocompatible Composite Materials Research Articles

Obtaining New Biocompatible Composite Materials with Antibacterial Properties Based on Diatomite and Biologically Active Compounds.

This study aimed to create new composite materials based on diatomite-a non-organic porous compound-through its surface modification with bioactive organic compounds, both synthetic and natural. Chloramphenicol, tetrahydroxymethylglycoluril and betulin were used as modifying substances. Composite materials were obtained by covering the diatomite surface with bioactive substance compounds as a solution and material dispersion in it. The materials were characterized by IR spectroscopy, SEM and X-ray photoelectron spectroscopy. For the biocomposites, the hemolytic effect, plasma proteins' adsorption on the surface and the antibacterial activity of the obtained materials were studied. Results show that the obtained materials are promising for medicine and agriculture.

Highly stretchable nanocomposite piezofibers: a step forward into practical applications in biomedical devices.

High-performance biocompatible composite materials are gaining attention for their potential in various fields such as neural tissue scaffolds, bio-implantable devices, energy harvesting, and biomechanical sensors. However, these devices currently face limitations in miniaturization, finite battery lifetimes, fabrication complexity, and rigidity. Hence, there is an urgent need for smart and self-powering soft devices that are easily deployable under physiological conditions. Herein, we present a straightforward and efficient fabrication technique for creating flexible/stretchable fiber-based piezoelectric structures using a hybrid nanocomposite of polyvinylidene fluoride (PVDF), reduced graphene oxide (rGO), and barium-titanium oxide (BT). These nanocomposite fibers are capable of converting biomechanical stimuli into electrical signals across various structural designs (knit, braid, woven, and coil). It was found that a stretchable configuration with higher output voltage (4 V) and a power density (87 μW cm-3) was obtained using nanocomposite coiled fibers or knitted fibers, which are ideal candidates for real-time monitoring of physiological signals. These structures are being proposed for practical transition to the development of the next generation of fiber-based biomedical devices. The cytotoxicity and cytocompatibility of nanocomposite fibers were tested on human mesenchymal stromal cells. The obtained results suggest that the developed fibers can be utilized for smart scaffolds and bio-implantable devices.

Natural hydrocolloids as biocompatible composite materials for food applications

Consumer demands for more sustainable approaches towards traditional food-related products made natural hydrocolloids a focus of the modern food industry. Featuring biocompatibility, availability and unique physicochemical properties, hydrocolloids are infiltrating the trending production of guilt-free food alternatives and biodegradable functional food packaging. Recent research has highlighted the challenges in creating these products, which can be solved by a deeper understanding of the interactions between the components of a complex hydrocolloid-based mixture. This review summarizes the applications of natural hydrocolloids as promising multifunctional materials for innovative technologies that prioritize safety and sustainability of food-related products. It also provides an overview of their features with a focus on the gelling behaviour and ways to improve the hydrocolloid matrix to produce the materials with the desired texture, smell, appearance and functional properties.<br>The bibliographyincludes 563 references.

Fluorescent Nanoassembly of Tetrazole-Based Dyes with Amphoteric Surfactants: Investigation of Cyanide Sensing and Antitubercular Activity.

Tetrazole-based easily synthesizable fluorogenic probes have been developed that can form self-assembled nanostructures in the aqueous medium. Though the compounds could achieve detection of cyanide ions in apolar solvents, such as, THF, significant interference was observed from other basic anions, such as F-, AcO-, H2PO4-, etc. On the other hand, a highly specific response was observed for CN- ions in the aqueous medium. However, the sensitivity was so poor that it could hardly be useful for real-life sample analysis. Interestingly, the co-assembly of such probe molecules with hydroxyethyl-anchored amphoteric surfactants could drastically improve the sensitivity toward CN- ions in water without dampening their excellent selectivity. Also, it was observed that the degree of fluorescence response for CN- ions depends on the nature of the polyaromatic scaffolds (naphthyl vs anthracenyl), the nature of the surfactant assembly (micelle vs vesicle), etc. The mechanistic investigation indicates the hydrogen bonding interaction between the tetrazole -NH group and cyanide ions in the aqueous medium, which can effectively change the electronics of the tetrazole unit, resulting in alteration in the extent of charge transfer interaction. Then, the biocompatible composite materials (dye-surfactant assemblies at different ratios) were tested for antituberculosis activity. Fortunately, in a few cases, the compositions were found to be as effective as the commercially available antituberculosis drug, ethambutol.

Statistical Modeling and Optimization of Surface Roughness for PLA and PLA/Wood FDM Fabricated Items

During last decades fused deposition modeling (FDM) has emerged as a widely applied additive manufacturing technology for numerous engineering applications. The present work investigates the effects of two independent variables during FDM fabrication of conventional polylactic acid (PLA) and organic biocompatible composite material with coconut flour (PLA/w) on mean surface roughness (Ra) of fabricated items. The parameter optimization adopts a customized response surface (RSM) design, based on an L9 orthogonal array. The independent variables investigated, were nozzle temperature, NT (oC) and layer thickness, LT (mm) whilst regression models for Ra concerning both materials; PLA and PLA/W, were developed to correlate the independent parameters. Proper analysis was preceded, based on response surface analysis through contour plots. The regression models were further utilized as objective functions to minimize Ra for both filament materials with the use of grey-wolf optimization genetic algorithm (GWO)

Potential Applications of Hydroxyapatite-Mineralized-Collagen Composites as Bone Structure Regeneration: a Review

The composites materials are known for their flexibility due to the combinations of two or three different materials and manipulation of their compositions. The advantage offered by composite materials make it suitable for biomedical applications especially to be used for implants. There are three types of composites biocompatible materials namely Metal Matrix Composite (MMC), Ceramic Matrix Composite (CMC) and Polymer Matrix Composite (PMC). In order to produce the biocompatible composite materials, various manufacturing processes can be performed. The manufacturing processes of MMCs are stir casting and powder metallurgy; the typical manufacturing process for CMCs is powder metallurgy; and 3-D printing by synthesizing and cross-linking the networks is used for fabricating PMCs. One of the promising biocompatible composites is Hydroxyapatite Mineralized Collagen (HMC). The HMC is used to create bone scaffold in bone regeneration process. The suggested manufacturing process for HMC is hybrid process which collaborate Additive Manufacturing and CNC Machining. In this paper, the HMC is reviewed especially related with its properties, fabrication method, and existed experimentation. In addition, the three types of biocompatible composites are also discussed on the applications and its manufacturing processes.

Anisotropic Ion Conducting Particulate Composites for Bioelectronics.

Acquisition, processing, and manipulation of biological signals require transistor circuits capable of ion to electron conversion. However, use of this class of transistors in integrated sensors or circuits is limited due to difficulty in patterning biocompatible electrolytes for independent operation of transistors. It is hypothesized that it would be possible to eliminate the need for electrolyte patterning by enabling directional ion conduction as a property of the material serving as electrolyte. Here, the anisotropic ion conductor (AIC) is developed as a soft, biocompatible composite material comprised of ion‐conducting particles and an insulating polymer. AIC displays strongly anisotropic ion conduction with vertical conduction comparable to isotropic electrolytes over extended time periods. AIC allows effective hydration of conducting polymers to establish volumetric capacitance, which is critical for the operation of electrochemical transistors. AIC enables dense patterning of transistors with minimal leakage using simple solution‐based deposition techniques. Lastly, AIC can be utilized as a dry, anisotropic interface with human skin that is capable of non‐invasive acquisition of individual motor action potentials. The properties of AIC position it to enable implementation of a wide range of large‐scale organic bioelectronics and enhance their translation to human health applications.

Recycled Porcine Bone Powder as Filler in Thermoplastic Composite Materials Enriched with Chitosan for a Bone Scaffold Application.

This work aims to synthesize biocompatible composite materials loaded with recycled porcine bone powder (BP) to fabricate scaffolds for in-situ reconstruction of bone structures. Polylactic acid (PLA) and poly(ε-caprolactone) (PCL) were tested as matrices in percentages from 40 wt% to 80 wt%. Chitosan (CS) was selected for its antibacterial properties, in the amount from 5 wt% to 15 wt%, and BP from 20 wt% to 50 wt% as active filler to promote osseointegration. In this preliminary investigation, samples have been produced by solvent casting to introduce the highest possible percentage of fillers. PCL has been chosen as a matrix due to its greater ability to incorporate fillers, ensuring their adequate dispersion and lower working temperatures compared to PLA. Tensile tests demonstrated strength properties (6–10 MPa) suitable for hard tissue engineering applications. Based on the different findings (integration of PLA in the composite system, improvements in CS adhesion and mechanical properties), the authors supposed an optimization of the synthesis process, focused on the possible implementation of the electrospinning technique to develop PCL-BP composites reinforced with PLA-CS microfibers. Finally, biological tests were conducted to evaluate the antibacterial activity of CS, demonstrating the applicability of the materials for the biomedical field.

Biocompatible Composite Materials Based on Porous Hydroxyapatite Ceramics and Copolymer of Lactide and Glycolide

The intensive development of reconstructive surgery and traumatology provides a stable demand for new materials for implants. Of particular interest are materials based on hydroxyapatite, which are chemically close to the elemental composition and structure of bone and have similar bioactive properties. The aim of this work was to obtain porous composite materials based on hydroxyapatite and a copolymer of lactide and glycolide with properties suitable for use as a material for bone implants. The phase and elemental composition of composites was investigated by infrared spectroscopy, X-ray diffraction, and X-ray photoelectronic spectroscopy methods, and it was established how the production process affects the composition of materials. Regularities of the formation of porosity by the methods of low-temperature adsorption of nitrogen, immersion in a liquid (determination of the pore space volume), measurement of the diffusion coefficient through the material (Franz cell), and surface properties of composite materials by the Hammett indicator method, by the lying drop method were revealed. Regularities were established between the surface properties and the composition of materials and their biocompatibility determined using monocytes isolated from human peripheral blood.

Developments in the Field of Biocompatible Composite Materials Based on Biopolymers and Calcium Phosphates Adapted to Prototyping Technology

Data obtained by the authors upon creating composite materials based on biopolymers and calcium phosphates adapted to the prototyping technology are presented. Results concerning the creation and investigation of the properties of three-dimensional structures for the replacement of bone defects, as well as novel studies of the functionalization of three-dimensional prototypes based on calcium phosphates and a biopolymer, namely, modification of the surface of mineral–polymer materials by the biomimetic application of active calcium phosphates, are shown.

Synthesis of biocompatible calcium-phosphate compositions in ultrasound field

Introduction reflects the great interest of practical restorative medicine in artificial structures that mimic the structure and properties of natural bone tissue that are made from biocompatible composite materials suitable for restoring the integrity of bone elements of the musculoskeletal system. The Introduction also contains the physicochemical foundations and approaches to a new ultrasonic technologies providing accelerated production of a biocompatible composite material, precisely hydroxyapatite particles in a collagen matrix. Experimental part contains a description of methods and equipmets for accelerated production of a hydroxyapatite suspension in the field of a hydroacoustic emitter, which ensures that the cavitation threshold at room temperature is exceeded, at which intense acoustic vortex microflows provide a decrease in diffusion restrictions, accelerating the interaction between reacting components. The reaction is carried out with the simultaneous supply of an aqueous solution of calcium monophosphate hydrate and a suspension of calcium hydroxide. The resulting finished product is separated using an ultrasonic self-cleaning filter, where the same, by nature, microflows allow the implementation of a continuous accelerated separation of synthesized particles in an ultrasonic self-cleaning filter of the installation, where, after separation, the precipitate is also subjected to cleaning. The resulting particles of hydroxyapatite mixed with the solution collagen and homogenized in an ultrasonic field at frequency of 22 kHz and an energy density in the reaction volume from 1 to 10 W / cm3. Obtained homogenate can be easily used to create various implant designs with predetermined sizes and shapes and after freezedrying was transformed in biocompatible composite with a porous structure. To control biocompatibility, samples of this composite in form of thin plate was sewed under the skin into the scruff of white lab rats. A suspension of hydroxyapatite mechanically combined with the collagen during 30 s homogenization by ultrasound at frequency of 22 kHz and at energy density of 3 W / cm3, form a complex that is freeze-dried, after which it can be used to form the biocomposite body with porous structure and with given dimensions and shapes. Subcutaneous implantation of plates of a calcium-phosphate biocomposite with a biodegradable polymer collagen, into the scruff of a laboratory white mouse showed its good biocompatibility with tissues of a living organism, without causing either immediate or delayed adverse events in them.

Arrays of Biocompatible and Mechanically Robust Microchambers Made of Protein-Polyphenol-Clay Multilayer Films.

There is a growing demand for biocompatible and mechanically robust arrays of microcompartments loaded with minute amounts of active substances for sensing or controlled release applications. Here we report on a novel biocompatible composite material, protein-polyphenol-clay (PPC) multilayer film. The material is shown to be strong enough to make robust microchambers retaining the shape and dimensions of truncated square pyramids. We study the mechanical properties and biocompatibility of the PPC microchambers and compare them to those made of synthetic polyelectrolyte multilayer film, poly(styrenesulfonate)-poly(allylammonium) (PSS-PAH). The mechanical properties of the microchambers were characterized under uniaxial compression using nanoindentation with a flat-punch tip. The effective Young's modulus of PPC microchambers, 166 ± 53 MPa, is found to be lower than that of PSS-PAH microchambers, 245 ± 52 MPa. However, the capacity to elastically absorb the energy of the former, 2.4 ± 1.0 MPa, is marginally higher than of the latter, 2.0 ± 1.3 MPa. Arrays of microchambers were sealed onto a polyethylene film, loaded with a model oil-soluble drug, and their biocompatibility was tested using an ex vivo 3D human skin reconstruct model. We found no evidence for toxicity with the PPC microchambers; however, PSS-PAH microchambers stimulated reduced cell density in the epidermis and significantly affected epidermal-dermal attachment. Both materials do not alter skin cell proliferation but affect skin cell differentiation. We interpret that rather than affecting epidermal barrier function, these data suggest the applied plastic films with microchamber arrays affect transpiration, normoxia, and moisture exchange.

Morphological, structural and cytotoxic behavior of starch/silver nanocomposites with synthesized silver nanoparticles using Stevia rebaudiana extracts

The synthesis of silver nanoparticles (AgNPs) using a Stevia rebaudiana aqueous extract and their dispersion in starch in order to obtain starch/AgNps nanocomposites are shown in this study. The AgNPs and the starch/AgNPs nanocomposites have been characterized by ultraviolet–visible spectroscopy, optical microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis. Furthermore, the interaction of starch/AgNPs nanocomposites with a MCF-7 breast cancer cell line is analyzed. AgNPs with an average size around 15–20 nm have been obtained. starch/AgNPs nanocomposite morphology changes with the content of silver (3, 5 and 8 mM), from totally separated and dispersed nanoparticles to ribbon-type morphology. The diffraction pattern of the starch/AgNPs-3 nanocomposite indicates the formation of silver chloride nanoparticles (AgClNPs). A cytotoxic behavior of starch/AgNPs-3 nanocomposite on MCF-7 cancer cells with less damage to normal cells is observed. Hence, the high dispersion of the AgNPs or AgClNPs in starch could be influencing the selective cytotoxic behavior. Thus, this study proposes the generation of biocompatible composite materials, with AgNPs immobilized on starch. These materials have selective action against breast cancer cells, where the selectivity is controlled through the AgNPs dispersion on the biopolymer.

Synthesis and characterization of conductive flexible cellulose carbon nanohorn sheets for human tissue applications

BackgroundConductive sheets of cellulose and carbon nanomaterials and its human skin applications are an interesting research aspect as they have potential for applications for skin compatibility. Hence it is needed to explore the effects and shed light on these applications.MethodTo fabricate wearable, portable, flexible, lightweight, inexpensive, and biocompatible composite materials, carbon nanohorns (CNHs) and hydroxyethylcellulose (HEC) were used as precursors to prepare CNH-HEC (Cnh-cel) composite sheets. Cnh-cel sheets were prepared with different loading concentrations of CNHs (10, 20 50,100 mg) in 200 mg cellulose. To fabricate the bio-compatible sheets, a pristine composite of CNHs and HEC was prepared without any pretreatment of the materials.ResultsThe obtained sheets possess a conductivity of 1.83 × 10− 10 S/m and bio-compatible with human skin. Analysis for skin-compatibility was performed for Cnh-cel sheets by h-CLAT in vitro skin sensitization tests to evaluate the activation of THP-1 cells. It was found that THP-1 cells were not activated by Cnh-cel; hence Cnh-cel is a safe biomaterial for human skin. It was also found that the composite allowed only a maximum loading of 100 mg to retain the consistent geometry of free-standing sheets of < 100 μm thickness. Since CNHs have a unique arrangement of aggregates (dahlia structure), the composite is homogeneous, as verified by transmission electron microscopy (TEM) and, scanning electron microscopy (SEM), and other functional properties investigated by Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), conductivity measurement, tensile strength measurement, and skin sensitization.ConclusionIt can be concluded that cellulose and CNHs sheets are conductive and compatible to human skin applications.

PGlu-Modified Nanocrystalline Cellulose Improves Mechanical Properties, Biocompatibility, and Mineralization of Polyester-Based Composites.

The development of biocompatible composite materials is in high demand in many fields such as biomedicine, bioengineering, and biotechnology. In this study, two series of poly (D,L-lactide) and poly (ε-caprolactone)-based films filled with neat and modified with poly (glutamic acid) (PGlu) nanocrystalline cellulose (NCC) were prepared. An analysis of scanning electron and atomic force microscopies’ results shows that the modification of NCC with poly (glutamic acid) favored the better distribution of the nanofiller in the polymer matrix. Investigating the ability of the developed materials to attract and retain calcium ions led to the conclusion that composites containing NCC modified with PGlu induced better mineralization from model solutions than composites containing neat NCC. Moreover, compared to unmodified NCC, functionalization with PGlu improved the mechanical properties of composite films. The subcutaneous implantation of these composite materials into the backs of rats and the further histological investigation of neighboring tissues revealed the better biocompatibility of polyester materials filled with NCC–PGlu.

Montmorillonite-Modified Reduced Graphene Oxide Stabilizes Copper Nanoparticles and Enhances Bacterial Adsorption and Antibacterial Activity.

To increase antibacterial activity and reduce the cytotoxicity of copper nanoparticles (CuNPs), we used reduced graphene oxide with montmorillonite to support CuNPs and fixed CuNPs on reduced graphene oxide to synthesize the hybrid montmorillonite-reduced graphene oxide copper nanoparticles (MMT-rGO-CuNPs). The synthesized MMT-rGO-CuNPs complex showed a stronger antibacterial activity against Gram-positive bacteria S. aureus than Gram-negative E. coli. This may be due to the protective effect of the outer membrane of E. coli, as well as the fact that the MMT-rGO-CuNPs complex adsorbs S. aureus more strongly than E. coli. The hybrid molecule's antibacterial efficacy is the combined result of the synergistic effects of electrostatic adsorption and copper ion sterilization ability. At the same time, the MMT-rGO-CuNPs complex exhibits a lower cytotoxicity than PVP-CuNPs and provides a biocompatible composite material with a reduced cytotoxicity.

Producing of nonwoven materials by electrospinning the biocompatible polymers with chitosan addition

The object of research is biocompatible composite nanofiber nonwoven materials with antiseptic properties, obtained by the electrospinning method. One of the most problematic places is the creation of a nonwoven biocompatible composite material with bactericidal properties; it has not previously been converted into fibers by electrospinning through high energy and financial costs. The composition of biocompatible polymers is used: chitosan, polyvinyl acetate (PVAC) and polyvinyl alcohol (PVA). The electrospinning method on the capillary type laboratory installation with a «bottom-up» solution is proposed for the production of nonwoven polymeric materials. Biocompatible composite nonwovens with antiseptic properties are obtained. This is due to the fact that the proposed method of electrospinning allows to obtain nonwoven materials with a certain statistical distribution of fibers, has several features when a solution of chitosan in lactic acid is introduced into the composition. In particular, for the composition based on PVA, the proportion of fibers with a diameter of 0.5 – 0.62 μm increased by 9 %, while for compositions based on PVAc it decreased by 21 %. It is established that the optimal voltage of the electric field is 30 kV and the distance between the electrodes is 9 – 11 cm for the production of fibers from biocompatible PVA and PVAc with the addition of chitosan. As a result of studies of the morphological features of the fibers obtained by optical polarization microscopy, it has been proved that with certain parameters of electrospinning, fibers with a diameter from 0.5 to 1.6 μm are obtained. As a result of determining the statistical distribution of polymer fibers in nonwoven material in diameter, it has been found that 69 – 94 % of the fibers have a diameter of 0.5 – 0.72 μm. A part of the fibers obtained in the laboratory installation of capillary electrospinning correspond to the area of nano-dimensions, which opens up prospects for obtaining biocompatible nanofibers with antiseptic and fungicidal properties. Therefore, the production of polymer biocompatible nonwovens by electrospinning can be used to create therapeutic systems.

High-Performance Flexible Bio-Electronics for Electrophysiological Recordings

Recently, bio-electronic devices which can in real-time collect electrophysiological signals such as electrocardiograms (ECGs), electromyograms (EMGs), and electroencephalograms (EEGs) have been actively investigated corresponding to the change in healthcare monitoring paradigm. Flexible bio-electronics which are attachable to the human skin can collect the important bio-signals regardless of spatial and temporal constraints differently with conventional rigid bio-electronics. However, most of studies on the fabrication of flexible bio-electronics require high-cost equipment and complicated process. In this presentation, we will demonstrate highly sensitive flexible bio-electrodes using biocompatible composite materials, which can detect electrophysiological signals (such as EMG, and ECG) more accurately without the negative aspects during the wearing. We will also discuss the practical approach for the flexible bio-electronics fabricated using solution-process at low-temperature in an ambient atmosphere. We believe that this work can contribute to realize wearable nanoelectronics embedded into the healthcare monitoring systems. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (NRF-2017R1A2B2003808).

Investigations for Enhancing Wear Properties of Rapid Tooling by Reinforcement of Nanoscale Fillers for Grinding Applications

In this work, investigations were made for enhancing wear properties of rapid tooling (RT) by reinforcement of fillers (nanoscaled) for grinding applications. The RT has been prepared by using biocompatible composite material (BCCM) feed stock filament (consisting of Nylon 6 as a binder, reinforced with biocompatible nanoscale Al2O3 particles) on fused deposition modeling (FDM) for the development of grinding wheel having customized wear-resistant properties. A comparative study has been conducted under dry sliding conditions in order to understand the tribological characteristics of FDM printed RT of BCCM and commercially used acrylonitrile butadiene styrene (ABS) material. This study also highlights the various wear mechanisms (such as adhesive, fatigue, and abrasive) encountered during experimentation. Finally, the FDM printed RT of proposed BCCM feedstock filament is more suitable for grinding applications especially in clinical dentistry.

Preparation and enhanced structural integrity of electrospun poly(ε-caprolactone)-based fibers by freezing amorphous chains through thiol-ene click reaction

Facile preparation and UV stabilization of electrospun poly(e-caprolactone) (PCL)/2-methyl-3-(trimethoxysilyl) propylester (M8POSS)/pentaerythritol tetrakis(3-mercaptopropionate) (PETM) composite fibers via thiol-ene click reaction were investigated. The morphological studies clearly showed the M8POSS and PETM macromers were excluded from PCL crystalline phase during electrospinning. The cross-linking reaction occurs in the amorphous phase of PCL fibers and possibly the fiber surface. By locking amorphous PCL chains into the cross-linked M8POSS and PETM through thiol-ene click reaction, we are able to fabricate PCL/POSS composite fibers, which can remain structural stability under UVC for longer period of time. The facile fabrication of the composite fibers via thiol-ene click reaction reported here provided valuable insight into not only the surface coating of medical devices but also new biocompatible composite materials.