Biomimetic Orthopedic Footwear Advanced Insole Materials to Be Used in Medical Casts for Weight-Bearing Monitoring.

Fabrication, characterization and testing of protective biomimetic orthopedic footwear advanced insole materials are introduced. The main objective of this material is to preserve and isolate a set of sensors for the Weight-Bearing Monitoring System (WBMS) device. Twenty-one samples of renewably sourced Polyurethane Foam (PUF) composed of poly(trimethylene ether) glycol (PO3G) and unmodified castor oil (CO) were synthesized and evaluated according to predetermined criteria. Response surface methodology of Box-Behnken design was applied to study the effect of the polyols ratio, isocyanate index (II), and blowing agent ratio on the properties (hardness, density) of PUFs. Results showed that CO/PO3G/Tolyene Diisocyanate (TDI) PUFs with hardness Shore A 17-22 and density of 0.19-0.25 g/cm3 demonstrate the required characteristics and can potentially be used as a durable and functional insole material. Phase separation studies have found the presence of well-segregated structures in PUFs having polyols ratio of CO:PO3G 1:3 and low II, which further explains their extraordinary elastic properties (400% elongation). Analysis of cushioning performance of PUF signified that five samples have Cushioning Energy (CE) higher than 70 N·mm and Cushioning Factor (CF) in the range of 4-8, hence are recommended for application in WBMS due to superior weight-bearing and pressure-distributing properties. Moreover, the developed formulation undergoes anaerobic soil bacterial degradation and can be categorized as a "green" bio-based material.

Prosthetic Joint Infections: Biofilm Formation, Management, and the Potential of Mesoporous Bioactive Glass as a New Treatment Option.

Infection of prosthetic joints is one of the biggest challenges to a successful replacement of the joint after a total joint arthroplasty. Such infections are caused by bacterial colonies that are difficult to treat by systemic delivery of antibiotics. Local delivery of antibiotics can prove to be the solution to such a devastating outcome that impacts patients' health and ability to regain function in their joints as well as costs the healthcare system millions of dollars every year. This review will discuss prosthetic joint infections in detail with a focus on the development, management, and diagnosis of the infections. Surgeons often opt to use polymethacrylate cement locally to deliver antibiotics; however, due to the rapid release of antibiotics, non-biodegradability, and high chance of reinfection, the search for alternatives is in high demand. One of the most researched alternatives to current treatments is the use of biodegradable and highly compatible bioactive glass. The novelty of this review lies in its focus on mesoporous bioactive glass as a potential alternative to current treatments for prosthetic joint infection. Mesoporous bioactive glass is the focus of this review because it has a higher capacity to deliver biomolecules, stimulate bone growth, and treat infections after prosthetic joint replacement surgeries. The review also examines different synthesis methods, compositions, and properties of mesoporous bioactive glass, highlighting its potential as a biomaterial for the treatment of joint infections.

Green Biodegradable Polylactide-Based Polyurethane Triblock Copolymers Reinforced with Cellulose Nanowhiskers.

A novel series of biodegradable polylactide-based triblock polyurethane (TBPU) copolymers covering a wide range of molecular weights and compositions were synthesized for potential use in biomedical applications. This new class of copolymers showed tailored mechanical properties, improved degradation rates, and enhanced cell attachment potential compared to polylactide homopolymer. Triblock copolymers, (TB) PL-PEG-PL, of different compositions were first synthesized from lactide and polyethylene glycol (PEG) via ring-opening polymerization in the presence of tin octoate as the catalyst. After which, polycaprolactone diol (PCL-diol) reacted with TB copolymers using 1,4-butane diisocyanate (BDI) as a nontoxic chain extender to form the final TBPUs. The final composition, molecular weight, thermal properties, hydrophilicity, and biodegradation rates of the obtained TB copolymers, and the corresponding TBPUs were characterized using 1H-NMR, GPC, FTIR, DSC, and SEM, and contact angle measurements. Results obtained from the lower molecular weight series of TBPUs demonstrated potential use in drug delivery and imaging contrast agents due to their high hydrophilicity and degradation rates. On the other hand, the higher molecular weight series of TBPUs exhibited improved hydrophilicity and degradation rates compared to PL-homopolymer. Moreover, they displayed improved tailored mechanical properties suitable for utilization as bone cement, or in regeneration medicinal applications of cartilage, trabecular, and cancellous bone implants. Furthermore, the polymer nanocomposites obtained by reinforcing the TBPU3 matrix with 7% (w/w) bacterial cellulose nanowhiskers (BCNW) displayed a ~16% increase in tensile strength, and 330% in % elongation compared with PL-homo polymer.

Methods of pretreatment and their impacts on anaerobic codigestion of multifeedstocks: A review.

Anaerobic codigestion (AnCoD) has attracted attention owing to its advantages over conventional anaerobic digestion, and attempts are still going on to develop methods for improving the efficiency of this technology. Mostly, addition of cosubstrates without applying a proper pretreatment cannot adequately enhance the performance of the digestion. However, there is a lack of a comprehensive study on different pretreatment methods specific to the wide range of cosubstrates. This review aimed to (i) categorize pretreatment techniques that have been developed for improving AnCoD, (ii) present the results of the studies on the effect of pretreatment on improving AnCoD, and (iii) provide a comparison between pretreatment methods and their application for different types of cosubstrates. The findings primarily validated the influence of pretreatment to enhance the process by increasing biodegradability, improved hydrolysis, reduced hydraulic retention time (HRT), and improved methane production. The five main categories of pretreatment employed in codigestion included the following: mechanical, thermal, chemical, biological, and hybrid pretreatment. Among them, mechanical and biological pretreatment have the most and least application in codigestion, respectively. Greater efforts are required on the application of biological pretreatment and cost-benefit analysis of different pretreatment options on the variety of the cosubstrates. PRACTITIONER POINTS: Pretreatment can significantly enhance biomethane production in anaerobic digestion Anaerobic codigestion along with pretreatment can further enhance the conventional anaerobic digestion of single feedstock Mechanical and biological methods have been the most and least practiced pretreatment options Selection of applicable pretreatment option to enhance methane production is subject to the type of cosubstrates in the system There is a research gap in evaluating the application of biological pretreatment for various types of cosubstrates.

Production and recovery of poly-3-hydroxybutyrate bioplastics using agro-industrial residues of hemp hurd biomass.

The present study describes production and recovery of poly(3-hydroxybutyrate) P(3HB) from agro-industrial residues. Production was conducted using Ralstonia eutropha strain with hemp hurd biomass hydrolysates sugars as a carbon source and ammonium chloride as the nitrogen source. Results show that maximum hydrolysis yield of 72.4% was achieved with total sugar hydrolysate concentration (i.e., glucose and xylose) of 53.0 g/L. Sugar metabolism by R. eutropha showed preference for glucose metabolism over xylose. Under optimum conditions, cells can accumulate P(3HB) polymer in quantity up to 56.3 wt% of the dry cell weight. This corresponds to total production of 13.4 g/L (productivity of 0.167 g/L h). Nitrogen source showed no adverse effect on P(3HB) biosynthesis, but rather on cell growth. Among several examined recovery techniques, ultrasonic-assisted sodium dodecyl sulfate (SDS) recovered bioplastic directly from the broth cell concentrate with P(3HB) content of 92%. Number average molecular weights (Mn) of final recovered bioplastic were in the range of 150-270 kDa with polydispersity index (Mw/Mn) in the range of 2.1-2.4.

Investigating the effect of multi-functional chain extenders on PLA/PEG copolymer properties.

Biodegradable copolymers polylactic acid-co-poly ethylene glycol (PLA-co-PEG) were synthesized at a specific volume ratio (PLA/PEG) (80/20) using direct melt polycondensation without solvent. The effects of an oligomeric chain extender (CE) on the mechanical, molecular weight, thermal stability, and degradation were evaluated. The copolymers were tailored by introducing classes of CE contents (0.25, 0.5, 0.075, 1.0, 1.25, and 1.5wt%) (styrene- glycidyl acrylate copolymer). Apparently, the mechanical properties of copolymers were enhanced in the presence of CE. A long chain branch structure has led to a slight improvement of tensile strength to reach 70MPa at CE 1.25%, compared with 60MPa for neat PLA. A significant increase of 17% was observed for the elongation at break of copolymers after addition of CE 1.25%. In addition, the impact strength increased to 7.9KJ/m2 in the ranges of CE 1-1.25%. Melt flow index dramatically reduces with the addition of CE contents. Gas Permeation Chromatography (GPC) showed that the addition of CE 1.25% has resulted in increasing the PLA molecular weight to 132.569kDa with a broad molecular weight distribution, MWD (2.066), and bimodal distribution. Differential Scanning Calorimetric (DSC) results revealed that the chain extension process improved glass transition temperature (Tg) 62°C, melting temperature (Tm) 161°C, and crystallinity (X%) 34.9% as a result of CE 1.25%. Thermal gravimetric analyses (TGA) results indicated that the CEs have a positive effect on the enhancement of thermal stability. Moreover, Scanning Electron Microscopic (SEM) showed that the compatibility and interfacial adhesion between the PLA and PEG chains were enhanced in the existence of the CE contents. The weight loss of the copolymer during 30days of degradation time was 28%, while the weight loss of CE 1.5% was only 3% during the same time interval.

Novel clostridial fusants in comparison with co-cultured counterpart species for enhanced production of biobutanol using green renewable and sustainable feedstock.

In this work, biobutanol was produced through simultaneous saccharification and fermentation (SSF) of wheat straw (WS) that traditionally produces acetone, butanol and ethanol solvents (ABE). Thermal stability was imparted to two mesophilic clostridial wild strains (Clostridium beijerinckii and Clostridium acetobutylicum) through protoplast fusion with that of a corresponding thermophilic clostridial species (Clostridium thermocellum). Production was pursued by the fused strains at 45 °C compared to that of the corresponding co-cultures at 35 °C. Results showed that the fused strains generally achieved higher production at 45 °C than that of the corresponding co-cultures at 35 °C. Highest butanol production of 13.82 g/L was recorded with C. beijerinckii fusant, with ABE solvents production of 23 g/L (yields of 0.17 and 0.57, respectively). Total sugar consumption of this strain was the highest among all strains and was 84%. Fused strains also showed immense level of tolerance towards butanol toxicity compared to the wild strains. Filter paper enzyme assay demonstrated that fused strains were able to produce cellulolytic enzymes in the range of 58.73-68.52 FPU/ml. Cellulosome producing C. thermocellum and its ability to ferment sugars offers a promising future in biofuels through eliminating the need to add external enzymes. Generally, productions reported in the present study were higher than literature where biobutanol stripping systems were employed to eliminate toxicity during production. This demonstrates a clear potential for improving productivity and yield at a larger-scale facility.

Production of green biodegradable plastics of poly(3-hydroxybutyrate) from renewable resources of agricultural residues.

This work describes potential opportunities for utilization of agro-industrial residues to produce green biodegradable plastics of poly(3-hydroxybutyrate) (PHB). Wheat straws were examined with good efficacy of carbon substrates using Cupriavidus necator. Production was examined in separate hydrolysis and fermentation (SHF) in the presence and absence of WS hydrolysis enzymes, and in simultaneous saccharification and fermentation (SSF) with enzymes. Results showed that production of PHB in SSF was more efficient in terms of viable cell count, cell dry weight, and PHB production and yield compared to those of SHF and glucose-control cultures. While glucose control experiment produced 4.6 g/L PHB; SSF produced 10.0 g/L compared to 7.1 g/L in SHF when utilizing enzymes during WS hydrolysis. Results showed that most of sugars produced during the hydrolysis were consumed in SHF (~98 %) compared to 89.2 % in SSF. Results also demonstrated that a combination of glucose and xylose can compensate for the excess carbon required for enhancing PHB production by C. necator. However, higher concentration of sugars at the beginning of fermentation in SHF can lead to cell inhibition and consequently catabolite repressions. Accordingly, results demonstrated that the gradual release of sugars in SSF enhanced PHB production. Moreover, the presence of sugars other than glucose and xylose can eliminate PHB degradation in medium of low carbon substrate concentrations in SSF.

Production of green biocellulose nanofibers by Gluconacetobacter xylinus through utilizing the renewable resources of agriculture residues.

The present study demonstrates the ability to produce green biocellulose nanofibers using the renewable resources of agriculture residues. Locally grown wheat straws (WS) were hydrolyzed under different conditions. Their hydrolysates were utilized to produce the nanofibers in separate hydrolysis fermentation process by Gluconacetobacter xylinus strain bacterium. Highest biocellulose production of ~10.6 g/L was achieved with samples that were enzymatically hydrolyzed. Moreover, acidic hydrolyzed WS produced up to 9.7 g/L, with total sugar concentrations in culture media of 43 g/L. Generally, enzymatic hydrolysis of WS resulted in more total sugar concentration than the acidic hydrolysis (i.e., 52.12 g/L), while water hydrolysis produced the least. This can be related to utilizing Xylanase in addition to Cellulase and Beta-glucosidase that helps to hydrolyse WS dry basis of cellulose and hemicelluloses. Sugar mixtures produced under all hydrolysis conditions were mainly composed of glucose and xylose with average percentages of 56 and 28 %, respectively. Acidic hydrolysis at higher acid concentration, as well as soaking WS in the acidic solution for longer time, improved the total sugar concentration in the culture media by 18 %. Conducting thermal treatment at more intense conditions of higher temperature or heating time improved the total sugar produced with acidic hydrolysis. These conditions, however, resulted in further production of furfural, which considerably affected bacterial cells proliferation. This resulted in lowest sugar consumption in the range of 62-64 % that affected final BC production.

Macromixing hydrodynamic study in draft-tube airlift reactors using electrical resistance tomography.

The present study summarizes results of mixing characteristics in a draft tube airlift bioreactor using ERT. This technique offers the possibility for noninvasive and nonintrusive visualization of flow fields in the bioreactor and has rarely been utilized previously to analyze operating parameters and mixing characteristics in this type of bioreactors. Several operating parameters and geometric characteristics were examined. In general, results showed that the increase in superficial gas velocity corresponds to an increase in energy applied and thus, to a decrease in mixing time. This generally corresponded to an increase in liquid circulation velocity and shear rate values. Bottom clearances and draft tube diameters affected flow resistance and frictional losses. The influence of sparger configurations on mixing time and liquid circulation velocity was significant due to their effect on gas distribution. However, the effect of sparger configuration on shear rate was not significant, with 20% reduction in shear rates using the cross-shaped sparger. Fluid viscosity showed a marked influence on both mixing times and circulation velocity especially in the coalescing media of sugar and xanthan gum (XG) solutions. Results from this work will help to develop a clear pattern for operation and mixing that can help to improve several industrial processes, especially the ones related to emerging fields of technology such as the biotechnology industry.

Potential of biocellulose nanofibers production from agricultural renewable resources: preliminary study.

In the present preliminary study, we report results for the biocellulose nanofibres production by Gluconacetobacter xylinus. Production was examined by utilizing different feedstocks of single sugars and sugar mixtures with compositions similar to the acid hydrolyzates of different agriculture residues. Profiles for cell proliferation, sugar consumption, and the subsequent pH changes were thoroughly analyzed. Highest biocellulose production of 5.65 g/L was achieved in fructose medium with total sugar consumption of 95.57%. Moreover, the highest production using sugar mixtures was 5.2 g/L, which was achieved in feedstock with composition identical to the acid hydrolyzate of wheat straws. This represented the highest biocellulose yield of 17.72 g/g sugars compared with 14.77 g/g fructose. The lowest production of 1.1 and 1.75 g/L were obtained in xylose and glucose media, respectively, while sucrose and arabinose media achieved relatively higher production of 4.7 and 4.1 g/L, respectively. Deviation in pH of the fermentation broths from the optimum value of 4-5 generally had marked effect on biocellulose production with single sugars in feedstock. However, the final pH values recorded in the different sugar mixtures were approximately 3.3-3.4, which had lower effect on production hindrance. Analyzing profiles for sugars' concentrations and cell growth showed that large amount of the metabolized sugars were mainly utilized for bacterial cell growth and maintenance, rather than biocellulose production. This was clearly observed with single sugars of low production, while sugar consumption was rather utilized for biocellulose production with sugar mixtures. Results reported in this study demonstrate that agriculture residues might be used as potential feedstocks for the biocellulose nanofibres production. Not only this represents a renewable source of feedstock, but also might lead to major improvements in production if proper supplements and control were utilized in the fermentation process.

Nanostructured biomaterials and biocomposites from bacterial cellulose nanofibers.

Cellulose is one of the most abundant component of biomass in nature and the basic feedstock in paper and pulp industries. Cellulose fibres are relatively strong; have breaking strengths of up to 1 GN/m2 (10,000 MPa). Traditionally extracted from plant tissue (trees, cotton, etc.) cellulose can also be produced, using certain bacterial species, by fermentation in the form of nanofibers, yielding a very pure cellulose product with unique properties. Research in the biosynthesis of microbial cellulose and its application are being pursued intensively. Bacterial cellulose possesses unique physical properties that distinguish it from plant-derived cellulose. Its fibre has a high aspect ratio with a fibre diameter of 20-100 nm. As a result, it has a very high surface area per unit mass. This property, when combined with its very hydrophilic nature, results in very high liquid loading capacity. The unique properties of this natural and biocompatible nanofiber make it an attractive candidate for a wide range of applications in many different industries especially those related to Biomedical and Biotechnology.

Applicability of airlift draft-tube fluidized bioreactors for binary protein mixture bioseparation.

An airlift draft-tube fluidized bioreactor has been designed and tested for applications in protein bioseparation. Operating parameters and geometrical dimensions of the bioreactor were optimized to ensure fluid circulation in a defined cyclic pattern between the riser and the downcomer. The overall directionality of liquid flow generates homogeneous field of low shear and achieves good mixing efficiency. Bioseparation of proteins was achieved from solutions containing both BSA and BHb at different initial concentrations and at pH 7. Similar adsorption capacities of both proteins were observed in single protein adsorption experiments at pH 7. Compressibility of BHb allowed for high adsorption capacity, in addition to the hydrophobic interaction forces. Apparently the homogeneous and lower shear generated by the airlift bioreactor reduces the compressibility of adsorbed BHb. This allowed for higher BSA adsorption from solutions containing BSA and BHb mixtures. Conventional batch adsorption experiments showed more adsorption of BHb, which reduces bioseparation efficiency.

Novel thymine-functionalized polystyrenes for applications in biotechnology. 2. Adsorption of model proteins.

This paper investigates the adsorption of bovine serum albumin (BSA) and bovine hemoglobin (BHb) model proteins onto novel thymine-functionalized polystyrene (PS-VBT) microspheres, in comparison with polystyrene (PS) microspheres. Maximum adsorption was obtained for both proteins near their corresponding isoelectric points (pI at pH = 4.7 for BSA and 7.1 for BHb). FTIR and adsorption isotherm analysis demonstrated that, although both proteins were physisorbed onto PS through nonspecific hydrophobic interactions, adsorption onto the functionalized copolymers occurred by both physisorption and chemisorption via hydrogen bonding. FTIR analysis also indicated conformational changes in the secondary structure of BSA and BHb adsorbed onto PS, whereas little or no conformation change was seen in the case of adsorption onto PS-VBT. Atomic force microscopy (AFM), consistent with the isotherm results, also demonstrated monolayer adsorption for both proteins. AFM images of BSA adsorbed onto copolymers with 20 mol % surface VBT loading showed exclusively end-on orientation. Adsorption onto copolymers with lower functionality showed mixed end-on and side-on orientation modes of BSA, and only the side-on orientation was observed on PS. The AFM results agreed well with theoretically calculated and experimentally obtained adsorption capacities. AFM together with calculated and observed adsorption capacity data for BHb indicated that this protein might be highly compressed on the copolymer surface. Adsorption from a binary mixture of BSA and BHb onto PS-VBT showed good separation at pH=7.0; approximately 90% of the adsorbed protein was BHb. The novel copolymers have potential applications in biotechnology.