Montmorillonite-Cellulose based Nano-Composites and Applications

Biomaterials have been widely used in dental composite materials or implants and their physical, mechanical, wear, and biocompatibility characteristics must be evaluated for clinical application. Extensive research has been committed to establishing various scientific methods for customizing the microstructure of dental biomaterials. As the ultimate goal of the selected implant material is the patient's safety and functionality, the current literature survey inspects and brings onward the vital features associated with the mechanical, biological, and microstructural properties of biomaterials used in dental composites or implants. The review study focuses on the successful use of diverse materials as an additive in bioceramics/fibers and the processing processes used to improve characteristics, allowing the material to be utilized in dental materials or implants. The influence of various fillers on the physical, chemical, mechanical, thermal, wear, and biological characteristics of fabricated dental restorative composite materials have been elaborately discussed. Furthermore, the design of experiment prospects is proposed to encourage new advancements in biomaterials research.

The use of different legume species, as green manure, may affect differently soil biological and chemical properties. The aim of this study was to evaluate the effect of four legumes species used as green manure on soil biological and chemical properties in short-term. We evaluated the following legume species: Crotalaria, Cajanus, Mucuna and Canavalia. The study was arranged in a completely randomised design with four replicates. The plants were incorporated into the soil (0-20 cm) by harrow and the chemical and biological properties were evaluated 30 and 60 days from the incorporation. Soil chemical and biological properties showed different trends according to legume species used. Soil P and K contents were highest in plot with Crotalaria, while soil Ca content was highest in plot with Mucuna. Soil microbial biomass was higher in plot with Mucuna as compared with others green manure species. Fluorescein diacetate hydrolysis was higher in plots with Mucuna and Canavalia than the others plots. Our results supported the hypothesis that different types of legume used as green manure affect differently the biological and chemical properties of soil. In this case, Mucuna was more effective to improve soil biological properties, while Crotalaria seems to be more efficient in the improvement of chemical properties. Key words: Organic fertilization, alternative agriculture, legumes.

The use of biodegradable/bio-based polymers is of great importance in addressing several issues related to environmental protection, public health, and new, stricter legislation. Yet some applications require improved properties (such as barrier or mechanical properties), suggesting the use of nanosized fillers in order to obtain bio-based polymer nanocomposites. In this work, bionanocomposites based on two different biodegradable polymers (coming from the Bioflex and MaterBi families) and two different nanosized fillers (organo-modified clay and hydrophobic-coated precipitated calcium carbonate) were prepared and compared with traditional nanocomposites with high-density polyethylene (HDPE) as matrix. In particular, the injection molding processability, as well as the mechanical and rheological properties of the so-obtained bionanocomposites were investigated. It was found that the processability of the two biodegradable polymers and the related nanocomposites can be compared to that of the HDPE-based systems and that, in general, the bio-based systems can be taken into account as suitable alternatives.

The effect of grain refinement of titanium on its mechanical performance and cell response

Bone repair biomedical materials and tissue engineering are widely applied in the medical field due to their ability to repair bone deficiencies and replace hard tissues. Biodegradable materials are used clinically worldwide because they prevent the need for secondary surgery. In recent decades, biodegradable materials have shown improved chemical, biological and mechanical properties. Biological properties such as degradation rate, while determining the healing process, must match with the mechanical properties also. Biodegradable materials are used in designing bone fracture implants that help in the bone healing process, which has become an interesting area of research. In this work, machine learning is applied to predict the properties of different materials and their degradation rate. This model also automatically generates the composition of biodegradable materials along with their mechanical and biological properties, which saves time taken while performing experimental analysis, and their subsequent failures.

Purpose – The main purpose of this research work is to study the effect of poly lactic acid (PLA) addition into poly (e-caprolactone) (PCL) matrices, as well the influence of the mixing process on the morphological, thermal, chemical, mechanical and biological performance of the 3D constructs produced with a novel biomanufacturing device (BioCell Printing). Design/methodology/approach – Two mixing processes are used to prepare PCL/PLA blends, namely melt blending and solvent casting. PCL and PCL/PLA scaffolds are produced via BioCell Printing using a 300-μm nozzle, 0/90° lay down pattern and 350-μm pore size. Several techniques such as scanning electron microscopy (SEM), simultaneous thermal analyzer (STA), nuclear magnetic resonance (NMR), static compression analysis and Alamar BlueTM are used to evaluate scaffold's morphological, thermal, chemical, mechanical and biological properties. Findings – Results show that the addition of PLA to PCL scaffolds strongly improves the biomechanical performance of the constructs. Additionally, polymer blends obtained by solvent casting present better mechanical and biological properties, compared to blends prepared by melt blending. Originality/value – This paper undertakes a detailed study on the effect of the mixing process on the biomechanical properties of PCL/PLA scaffolds. Results will enable to prepare customized PCL/PLA scaffolds for tissue engineering applications with improved biological and mechanical properties, compared to PCL scaffolds alone. Additionally, the accuracy and reproducibility of by the BioCell Printing enables to modulate the micro/macro architecture of the scaffolds enhancing tissue regeneration.

Bio-based polymer nanocomposites from UPE/EML blends and nanoclay: Development, experimental characterization and limits to synergistic performance

This investigation intends to examine the mechanical, tribological, and biological properties of hybrid epoxy composites reinforced with nanohydroxyapatite (nHA) and short carbon fiber (SCF). Due to its advantageous mechanical, tribological, and biocompatibility features, the proposed E/SCFs-nHA hybrid composites are meant to be recommended for composite structures that can be used to develop fixation plates used in orthopedic applications. In this study, single-layer hybrid composites reinforced with SCFs and nHA in varying ratios, as well as pure epoxy (E) and epoxy-carbon fiber composites, were all fabricated by hand lay-up method. Tensile tests, 3-point bending tests, and Izod impact tests were performed to investigate their mechanical characteristics. Moreover, the hybrid composite samples were tested for their biological properties in simulation body fluid (SBF). Mechanical and biological properties were found to be enhanced according to the results. Consequently, the hybrid composite (E-10CF-3nHA) of 10% carbon fiber (CF) and 3% nanohydroxyapatite (nHA) performed the best in all tests.

Bio-based polymers have gained huge attention in the recent past for their application in various domains, especially food packaging. The petroleum-based polymers have a significant negative impact on the ecosystem owing to their non-biodegradability. Therefore, a sustainable yet efficient alternative is required which is both safe and non-toxic. Food packaging technologies with the latest innovations are promoting active and smart packaging applications which promise quick, safe and efficient ways to monitor the quality of stored foods. These materials are being explored in applications such as antimicrobial wraps, moisture barrier coatings, biodegradable trays, and oxygen-scavenging films. Nanotechnology has emerged as a superior alternative as it can enhance food protection while reducing the raw material requirement and waste generation. The present review focuses on the recent developments in active and smart food packaging with special emphasis on bio-based polymer nanocomposites. The various polymer nanocomposites, their properties and safety concerns with respect to food packaging are summarized in this review article besides providing prospects for the current research area.

Usefulness of middle infrared spectroscopy for an estimation of chemical and biological soil properties – Underlying principles and comparison of different software packages

The study evaluates and compares two procedures for selecting soil quality indicators (used for the construction of soil quality indices, SQI) by using diverse chemical, physical, and biological properties, and evaluates the role of soil microbiological properties in the construction of SQI. Different soil environments were selected from an extensive agricultural production site in the rolling pampa, Buenos Aires, Argentina. The plots included an undisturbed soil, a grassland soil, and continuous tilled soils with four different surface horizon depths (25, 23, 19, and 14 cm). Various properties were measured, and a minimum dataset was chosen by principal component analysis (PCA) considering all measured soil properties together (procedure A), or the PCA was performed separately according to classification as physical, chemical, or biological soil properties (procedure B). The measured soil properties involved physical, chemical, and biochemical properties determined by standard protocols used in routine laboratory analysis (simple SQI, SSQI) or more laborious protocols to determine microbial community structure and function by phospholipid fatty acid (PLFA) and catabolic response profile (CRP), respectively (complex SQI, CSQI). The selected properties were linearly normalised and integrated by the weight additive method to calculate SSQI A, SSQI B, CSQI A, and CSQI B indices. Two microbiological SQI (MSQI) were also calculated; MSQI 1 considered only biological properties according to the procedure used for calculating SQI; MSQI 2 was calculated by considering three selected microbiological parameters representing the size (microbial biomass carbon), activity (soil basal respiration), and functional diversity (evenness, determined by CRP) of the microbial communities. All of the constructed indices show the same differences among the study sites. The inclusion of CRP and PLFA data in the indices slightly increased, or did not increase, the index sensitivity. Microbiological indices had the same sensitivity as the indices integrated by physical, chemical, and biological properties. An evaluation of the SQI constructed by both procedures found no difference in sensitivity. However, SQI constructed by procedure B allowed evaluation of the effects of management practices on physical, chemical, and biological soil properties.

Indicating how different sources of organic matter (OM) may affect the properties of a wide range of soil types, at varying soil moisture (SM), is of significance in the agricultural fields. A large dataset of soil samples (0–30 cm) was collected from different parts of Iran (21 different agricultural regions, with a wide range of physical, chemical, and biological properties) to determine the effects of OM and varying SM on soil chemical (pH, salinity, and organic carbon) and biological (microbial biomass carbon, MBC) properties. The collected soil samples were incubated (9-month period) with the experimental treatments including OM (control (M1), 2% wheat straw (WS) (M2), and 2% biochar (BI) (M3)), at different SM levels (0.2 field capacity, FC (V1), 0.7 variable FC (V2), 0.7 constant FC (V3), and saturated moisture (V4)). Wheat straw was pyrolyzed (at 500°C) to produce BI, and their chemical properties were determined. BI salinity (3.1 dS/m) was significantly higher than WS (2.8 dS/m). The organic treatments, especially BI, significantly increased soil OM and MBC compared with the control treatment. The two sources of organic fertilization increased soil pH, OM, and MBC, though such effects were functions of varying soil moisture (drying and rewetting cycles). Due to higher C percentage (61%), the effects of BI, significantly affected by soil moisture, were more pronounced on soil parameters. The tested sources of organic matter (WS and BI), acting as functions of soil moisture, can strongly affect soil chemical and biological properties and contribute to higher efficiency of agricultural fields.

Concerns about environmental waste problems caused by non-biodegradable petrochemical-based plastic packaging materials as well as consumer demand for high-quality food products have led to increased interest in the development of biodegradable packaging materials using annually renewable natural biopolymers. Inherent shortcomings of natural polymer-based packaging materials such as low mechanical properties and low barrier properties can be recovered by applying nanocomposite technology. Polymer nanocomposites, especially natural biopolymer-layered silicate nanocomposites, exhibit markedly improved packaging properties due to large nanoparticle surface area and their significant aspect ratios. Additionally, natural biopolymer is susceptible to microorganisms, resulting in good biodegradability, which is one of the most promising aspects of its incorporation in packaging materials and industries. The present review article explains the various categories of nanoclay and bio-based polymer-based composites with particular regard to their application as packaging materials. It also gives an overview of the most recent advances and emerging new aspects of nanotechnology for development of composites for environmentally compatible food packaging materials.

Mono-material product design with bio-based, circular, and biodegradable polymers

Silk fibroin/collagen protein hybrid cell-encapsulating hydrogels with tunable gelation and improved physical and biological properties