Weeks Of Degradation Research Articles

Crack propagation in biodegraded wood

• Fungal attack in wood involves severe mechanical losses, even in the early stages, due to depolymerisation of polysaccharides. The safety of building components could therefore be affected. It is believed that fracture properties could be much more sensitive to decay than conventionally measured properties, such as weight loss. • In this study, we propose the application of a fracture mechanics test, which measures the fracture toughness, KIC, during the biodegradation process. Two softwoods commonly used in construction, maritime pine and Douglas fir, were inoculated with Poria placenta. Samples were removed twice a week to determine the evolution of the decrease in their mechanical properties. • Toughness was initially greater for maritime pine, but a significant decrease of this property was observed during decay progression, while KIC remained more stable for Douglas fir. For maritime pine there was a loss of 52% of KIC, after 6 weeks of degradation. This species appears to be less durable even with respect to weight loss, which is less sensitive to decay than toughness. • This is a promising test for bio-damage quantification; however, due to the wood heterogeneity, measurement of the true impact of biodegradation is still difficult.

Studies on the Relative Degradation and Interfacial Properties Between Jute/Polypropylene and Jute/Natural Rubber Composites

Jute fabrics (hessian cloth) reinforced polypropylene (PP) matrix composites (30% fiber by weight) were fabricated by compression molding. Tensile strength (TS), tensile modulus (TM), and percentage elongation at break (Eb) of the composites were found to be 32 MPa, 740 MPa, and 16%, respectively. Then jute fabrics reinforced solid natural rubber (NR)-based composites (30% fiber by weight) were also fabricated and it was found that TS, TM, and Eb of the jute/NR composites were 14 MPa, 120 MPa, and 94%, respectively. The mechanical properties of jute/PP and jute/NR composites were compared. Six weeks of degradation of the composites were performed in aqueous medium and it was found that jute/NR composites lost much of its original strength and modulus compared to that of the jute/PP composites. Interfacial shear strength (IFSS) of the jute/PP and jute/NR systems was investigated by using the single fiber fragmentation tests. The IFSS of jute/PP and jute/NR systems appeared to be 2.16 and 0.89 MPa, respectively. Fracture side of the composites was also studied by scanning electron microscope and suggested better fiber matrix adhesion between jute fiber and PP.

FTIR and NMR study of poly(lactide- co-glycolide) and hydroxyapatite implant degradation under in vivo conditions

The influence of hydroxyapatite (HAP) addition on the rate and mechanism of lactide- co-glycolide copolymer (PGLA) degradation after implantation ( in vivo study) was analyzed and compared with the process taking place during in vitro studies. Structural and phase changes of poly(lactide- co-glycolide) and its composite with hydroxyapatite were determined using IR and NMR spectroscopy. Degradation of PGLA and PGLA + HAP composite in biological environment proceeds faster than under in vitro condition. Concentration of glycolidyl units in the copolymer chain decreases and that of lactidyl units increases during in vivo degradation both, in PGLA and in PGLA + HAP composite. However, in the case of the composite the decrease of glycolidyl units concentration is slower and after 6 weeks of degradation the contents of lactidyl and glycolidyl units remain stable. On the other hand, PGLA + HAP composite degrades faster than pure PGLA. The addition of HAP nanoparticles distinctly accelerates degradation of PGLA copolymer which is probably connected with the increase of hydrophilicity of the composite and inhibition of semi-crystalline lactidyl domains formation during the degradation process. Observation of the bone tissue after implantation of PGLA + HAP allows to conclude that the degradation of the composite occurs simultaneously with the implant replacement by the bone cells.

Morphology, Molecular Mass Changes, and Degradation Mechanism of Poly-L-Lactide in Phosphate-Buffered Solution

The hydrolytic degradation of poly-L-lactide (PLLA) material was investigated in order to elucidate the effects of degradation on the morphology and molecular mass changes. The degradation mechanism and kinetics of PLLA were also studied. Molecular mass decreases and molecular weight distribution becomes broader continuously with an increase in the degradation time. After 20 weeks of degradation, there were a large number of diagonal striations on the surface and many erosive holes in the interior of the PLLA materials. The degradation mechanism of PLLA is indicative of an autocatalysis process and simple bulk hydrolysis at the same time, and the terminal hydroxyl group of the oligomer plays an important role. The degradation of PLLA complies with first-order kinetics, and the rate constant of the biodegradation process of PLLA is 9.2 × 10−3 day−1.

Selection of fat-degrading microorganisms for the treatment of lipid-contaminated environment

* Corresponding author. E-mail: cipinyte@biocentras.lt To develop eff ective microbial agents applicable to complex technology for grease wastes utilization, a total of 124 microorganisms were screened for their ability to degrade lipidic compounds. Th e screening yielded fi ve strains (UP2, F2, E13, Kl1 and N3) showing lipolytic activity and rapidly degrading sunfl ower and olive oil, tallow and lard. Among them, strains E13 and N3 were found to have the highest lipase activity and the more intensive rates of the degradation of saturated (palmitic and stearic) and unsaturated (oleic and linoleic) fatty acids and triglycerides containing these fatty acids. Th e strains were obtained from the culture collection of JSC “Biocentras” and identifi ed as Enterobacter aerogenes E13 and Arthrobacter sp. N3. When a mixed culture of strains E. aerogenes E13 and Arthrobacter sp. N3 was grown in a mineral medium containing 0.5% of sunfl ower oil, the hydrolysis products were diglycerides, monoglycerides and free fatty acids. Moreover, the mixed culture was consuming these hydrolysis products during cultivation at 30 °C. Investigation of lard biodegradation in black soil showed that a mixed culture of strains E. aerogenes E13 and Arthrobacter sp. N3 degraded lard about 7 times more intensively than indigenous soil microorganisms (aft er six weeks of degradation in black soil, the concentration of lard was reduced by 87.5 and 8.0%, respectively). Th erefore, the mixed culture of strains E. aerogenes E13 and Arthrobacter sp. N3 may be used for an eff ective grease waste reduction in a complex cleaning technology.

In vitro hydrolytic degradation of poly(para-dioxanone) with high molecular weight

The in vitro hydrolytic degradation of high molecular weight poly (para-dioxanone) was studied by examining the changes of weight retention, water absorption, pH value, tensile strength, break elongation, thermal properties, and morphology of high molecular weight PPDO in phosphate buffered saline (PBS) (pH 7.44) at 37°C for 8 weeks. During the degradation, all samples’ weight retention decreased and water absorption increased significantly, whereas hydrolysis rate of PPDO bars varied with molecular weight. Compared with lower molecular weight samples, higher molecular weight PPDO samples exhibited higher hydrolysis rate. The samples’ glass transition temperature (Tg) decreased notably, while the degrees of crystallinity (Dc) increased. The samples almost totally lost their tensile strengths and breaking elongation after 4 weeks of degradation. The results suggested that the stability of PPDO in vitro hydrolytic degradation increased with the increase of molecular weight.

Surface treatment of phosphate glass fibers using 2‐hydroxyethyl methacrylate: Fabrication of poly(caprolactone)‐based composites

Abstract2‐Hydroxyethyl methacrylate (HEMA) solution (1–10 wt %) was prepared in methanol and phosphate glass fibers were immersed in that solution for 5 min before being cured (irradiation time: 30 min) under UV radiation. Maximum polymer loading (HEMA content) was found for the 5 wt % HEMA solution. Degradation tests of the fibers in aqueous medium at 37°C suggested that the degradation of the HEMA‐treated fibers was lower than that of the untreated fibers. X‐ray photoelectron spectroscopy revealed that HEMA was present on the surface of the fibers. Using 5 wt % HEMA‐treated fibers, poly(caprolactone) matrix unidirectional composites were fabricated by in situ polymerization and compression molding. For in situ polymerization, it was found that 5 wt % HEMA‐treated fiber‐based composites had higher bending strength (13.8% greater) and modulus (14.0% greater) than those of the control composites. For compression molded composites, the bending strength and modulus values for the HEMA‐treated samples were found to be 27.0 and 31.5% higher, respectively, than the control samples. The tensile strength, tensile modulus, and impact strength of the HEMA composites found significant improvement than that of the untreated composites. The composites were investigated by scanning electron microscopy after 6 weeks of degradation in water at 37°C. It was found that HEMA‐treated fibers inside the composite retained much of their original integrity while the control samples degraded significantly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Retention of mechanical properties and cytocompatibility of a phosphate‐based glass fiber/polylactic acid composite

Polymers prepared from polylactic acid (PLA) have found a multitude of uses as medical devices. The main advantage of having a material that degrades is so that an implant would not necessitate a second surgical event for removal. In addition, the biodegradation may offer other advantages. In this study, fibers produced from a quaternary phosphate-based glass (PBG) in the system 50P(2)O(5)-40CaO-5Na(2)O-5Fe(2)O(3) (nontreated and heat-treated) were used to reinforce the biodegradable polymer, PLA. Fiber properties were investigated, along with the mechanical and degradation properties and cytocompatibility of the composites produced. Retention of mechanical properties overtime was also evaluated. The mean fiber strength for the phosphate glass fibers was 456 MPa with a modulus value of 51.5 GPa. Weibull analysis revealed a shape and scale parameter value of 3.37 and 508, respectively. The flexural strength of the composites matched that for cortical bone; however, the modulus values were lower than those required for cortical bone. After 6 weeks of degradation in deionized water, 50% of the strength values obtained was maintained. The composite degradation properties revealed a 14% mass loss for the nontreated and a 10% mass loss for the heat-treated fiber composites. It was also seen that by heat-treating the fibers, chemical and physical degradation occurred much slower. The pH profiles also revealed that nontreated fibers degraded quicker, thus correlating well with the degradation profiles. The in vitro cell culture experiments revealed both PLA (alone) and the heat-treated fiber composites maintained higher cell viability as compared to the nontreated fiber composites. This was attributed to the slower degradation release profiles of the heat-treated composites as compared to the nontreated fiber composites. SEM analyses revealed a porous structure after degradation, and it is clear that there are possibilities here to tailor the distribution of porosity within polymer matrices.

Preparation and in vitro degradation of porous three-dimensional silk fibroin/chitosan scaffold

Degradation behaviors of porous scaffolds play an important role in the engineering process of a new tissue. In this study, three-dimensional porous silk fibroin/chitosan (SFCS) scaffolds were successfully prepared by freeze-drying method. In vitro degradation behaviors of SFCS scaffolds have been systematically investigated up to 8 weeks in phosphate buffer saline (PBS) solution at 37 °C. The following properties of the scaffolds were measured as a function of degradation time: pore morphology, structure, weight loss, and wet/dry weight value. The pH value of the PBS solution during degradation was also detected. SFCS scaffolds maintained its porous structure till 6 weeks of degradation. During the first 2 weeks, the pH value fluctuated in a narrow range from 6.53 to 6.93. SFCS scaffolds degraded much more quickly during the first 2 weeks, and the weight loss reached 19.28 wt% after 8 weeks of degradation. The degradation process affects little SFCS scaffolds' swelling properties.

In vitro and in vivo degradability and cytocompatibility of poly( l-lactic acid) scaffold fabricated by a gelatin particle leaching method

Porous poly( l-lactic acid) (PLLA) scaffolds fabricated by a gelatin particle-leaching technique have good mechanical property and cytocompatibility, as demonstrated by a previous in vitro study. Here we investigate further the in vitro degradation of the scaffolds in terms of weight loss, water uptake, weight-average molecular weight, thermal behavior and morphology during a 39 week period in phosphate-buffered saline. The water uptake decreased dramatically during the initial stage due to release of the remaining gelatin, and then increased slightly with degradation time. The weight-average molecular weight decreased linearly as a function of time, while the crystallinity steadily increased with slightly decreased melting temperature. After degradation, many defects and big holes were seen in the scaffolds by scanning electron microscopy. Cartilage regeneration and scaffold disappearance in vivo were compared by implanting the construct into nude mice for 30–120 days. While the scaffolds maintained their intact pore structure after 23 weeks of degradation in vitro, they almost disappeared in vivo at the same time, implying a faster degradation rate in vivo. By 120 days after implantation, the scaffolds were hardly seen in the newly formed cartilage-like tissue. The regenerated cartilages could not maintain their predesigned shape after a long period of in vivo culture due to the weakening of the mechanical strength of the constructs as a result of PLLA degradation. The regions occupied initially by PLLA scaffold were filled later by collagen type II secreted by the chondrocytes, but with no evident basophilic proteoglycan.

Degradation and calcification in vitro of new bioresorbable terpolymers of lactides with an improved degradation pattern

Experimental implants produced from poly( l-lactide/ɛ-caprolactone/glycolide) 80/10/10% (polymer 1), poly( l-lactide/ dl-lactide/glycolide) 80/10/10% (polymer 2) and poly( l-lactide/ dl-lactide/glycolide) 80/5/15% (polymer 3) were subjected to in vitro degradation in a buffer solution at 37 °C and pH = 7.4 and calcification in vitro was performed at 37 °C in a simulated body fluid for 4, 8, 12, 16, 24, 28, 32 and 36 weeks. In vitro degradation was performed in static and pseudodynamic modes. Samples from poly( l-lactide) were used as a control. The changes in the materials during the course of degradation were assessed from the measurements of molecular weight, mechanical properties and crystallinity. The changes in the appearance of the materials upon degradation and calcification were observed using a scanning electron microscope with an EDAX attachment. The decrease of molecular weight at 4 weeks was 66% for polymer 1, 56% for polymer 2 and 20% for polymer 3. Samples retained 55% of their bending strength at 4 weeks (polymer 1), 50% at 12 weeks (polymer 2) and 99% at 12 weeks (polymer 3). The bending modulus of polymer 3 remained practically unchanged during the first 12 weeks of degradation. Subsequently it increased by 44% at week 16 and remained unchanged up to 24 weeks and next decreased to 33% of the initial value at the end of the experiment at week 32. The bending modulus of polymer 2 decreased 35% at week 8 and subsequently increased to 44% of the initial value at week 16 and remained at this level until week 20. Next the modulus decreased to 84% of the initial value at week 24. The bending modulus of polymer 1 progressively decreased over the first 12 weeks of degradation to 40% of the initial value. The maximum crystallinity attained by the samples at the end of the experiments was 60% for polymer 1 and 38% for polymers 2 and 3. In the static mode the pH remained constant up to week 8 for polymer 1, week 20 for polymer 2 and week 28 for polymer 3. It decreased to 3.8 at weeks 12, 20 and 36 for polymers 1, 2 and 3, respectively. All the samples underwent calcification from week 16 of the experiments with the Ca/P ratio ranging from 0.92 to 1.20.

Estudo da degradação "in vivo" de poli(L-co-D,L-ácido láctico) aplicado como prótese para regeneração nervosa periférica

A regeneração nervosa periférica auxilia na regeneração axonal e reorganização das fibras, atuando em lesões resultantes de esmagamento e secção do nervo. Nesse trabalho estudou-se a regeneração do nervo ciático utilizando-se tubos de poli(L-co-D,L-ácido láctico) preparados a partir de membranas obtidas por evaporação de solvente. Os tubos foram implantados no nervo ciático de 20 ratos da linhagem Spreague Dawley, durante 4, 8 e 12 semanas, sendo analisados por Calorimetria diferencial de varredura (DSC), Microscopia eletrônica de varredura (MEV), Cromatografia de permeação a gel (GPC), Análise termogravimétrica (TGA). O nervo regenerado foi avaliado pela técnica de Microscopia de luz (MO). Verificou-se um aumento do diâmetro do nervo em função do processo de degradação do tubo. Análises de DSC e GPC do PLDLA mostraram Tg em 57ºC e massa molar (Mw) de 197 989 gmol-1, respectivamente. Foram observadas nítidas variações nesses valores após 8 semanas de degradação, com Tg em 40ºC e Mw de 170000 g.mol-1. Dados de TGA também indicaram o processo de degradação com Ti em 333 ºC, antes da degradação e 305ºC, após 12 semanas. MEV mostrou formação de poros após 8 semanas de degradação. Esse estudo mostrou que tubos de PLDLA são promissores para a regeneração do nervo ciático.

Physical characterization of thin semi-porous poly(L-lactic acid)/poly(ethylene glycol) membranes for tissue engineering

This study examines physical properties of solvent-cast poly(L-lactic acid) (PLLA): poly(ethylene glycol) PEG membranes as a function of PEG molecular weight (MW) and incubation in vitro for 6 weeks. PEGs of MW 400, 1450 and 8000 were used. The morphological, thermal, mechanical and permeability properties of the membranes were studied prior to and after 3 and 6 weeks of incubation in phosphate-buffered saline (PBS) at 37°C. The membranes showed a thickness of about 35±5 μm and were found to be semi-porous, with a non-porous surface as well as a porous surface with pore-diameters of 0.5–5 μm. The surface pore size was found to be a function of PEG MW used. All membranes were mechanically strong, with elastic moduli and tensile strength of 150–440 MPa and 7–36 MPa, respectively, all through the 6-week incubation period. The lower-MW PEGs plasticized PLLA based on high initial percent elongation; however, the effect was lost after 3 weeks of incubation in PBS. All membranes except those fabricated with PEG 8000 were impermeable for up to 6 weeks of incubation in PBS. Permeability studies showed that only PLLA:PEG 8000 membranes were permeable to methylene blue after 3 weeks of degradation.

Hydrolytic Degradation of Poly(L-Lactide-co-Glycolide) Studied by Positron Annihilation Lifetime Spectroscopy and Other Techniques

Changes of the poly(L-lactide-co-glycolide) structure as a function of degradation time in phosphate-buffered saline for 7 weeks were investigated by gel permeation chromatography, differential scanning calorimetry, nuclear magnetic resonance (H NMR), and positron annihilation lifetime spectroscopy. Surface properties as wettability by sessile drop and topography by atomic force microscopy were also characterized. Chain-scission of polyester bonds in hydrolysis reaction causes a quite uniform decrease in molecular weight, and finally results in an increase in semicrystallinity. Molecular composition of the copolymer and water contact angle do not change considerably during degradation time. Atomic force microscopy studies suggest that the copolymer degrades by “in bulk” mechanism. The average size of the molecular-level free volume holes declines considerably after one week of degradation and remains constant till the sixth week of degradation. The free volume fraction decreases as a function of degradation time.

Preparation of poly(lactide- co-glycolide- co-caprolactone) nanoparticles and their degradation behaviour in aqueous solution

The tri-component copolymer poly(lactide- co-glycolide- co-caprolactone) (PLGC) was synthesized to prepare nanoparticles by the modified spontaneous emulsification solvent diffusion method (modified-SESD method); and the method was also modified by using the Tween60 instead of poly(vinyl alcohol) (PVA) as dispersing agent. The obtained nanoparticles have spherical shape and good particle distribution with mean size in the range from 100 to 200 nm. The in vitro degradation behaviour of PLGC nanoparticles was investigated. It was found that PLGC nanoparticles could remain stable during the degradation with no agglomeration. Compared with PLA and PLGA nanoparticles, the degradation rate of PLGC nanoparticles is faster. After 9 weeks of hydrolysis, the M n of PLGC is less by 10% of the original M n. The mean radius of the nanoparticles increases from 68 nm to 80 nm continuously during the first stage, and after 4 weeks of degradation, the particles' size decreases gradually from 80 nm to about 40 nm. These results suggest that the PLGC nanoparticles may show degradation-controlled drug release behaviour and seem to be a promising drug delivery system.

The mechanical properties and in vitro biodegradation and biocompatibility of UV-treated poly(3-hydroxybutyrate- co-3-hydroxyhexanoate)

Strong mechanical properties and controllable biodegradability, together with biocompatibility, are the important requirement for the development of medical implant materials. In this study, an ultraviolet (UV) radiation method was developed to achieve controlled degradation for bacterial biopolyester poly (3-hydroxybutyrate- co-3-hydroxyhexanoate) (PHBHHx) which has a low biodegradation rate that limits its application for many implant applications required quick degradation. When UV radiation was applied directly to PHBHHx powder, significant molecular weight (Mw) losses were observed with the powder, Mw reduction depended on the UV radiation time. At the same time, a broad PHBHHx Mw distribution was the result of inhomogeneous radiation. Interestingly, this inhomogeneous radiation helped maintain the mechanical properties of films made of the UV-radiated powder. In comparison, the PHBHHx films subjected to direct UV radiation became very brittle although their degradation was faster than that of the PHBHHx powders subjected to direct UV radiation. After 15 weeks of degradation in simulated body fluid (SBF), films prepared from 8 and 16 h UV-treated PHBHHx powders maintained 92% and 87% of their original weights, respectively, while the untreated PHBHHx films lost only 1% of its weight. Significant increases in growth of fibroblast L929 were observed on films prepared from UV-radiated powders. This improved biocompatibility could be attributed to increasing hydrophilic functional groups generated by increasing polar groups C–O and C O. In general, UV-treated PHBHHx powder had a broad Mw distribution, which contributed to fast degradation due to dissolution of low Mw polymer fragments, and strong mechanical property due to high Mw polymer chains. Combined with its improved biocompatibility, PHBHHx is one more step close to become a biomedical implant material.

A long‐term in vitro biocompatibility study of a biodegradable polyurethane and its degradation products

The biological safety of degradation products from degradable biomaterials is very important. In this study a new method is proposed to test the cytotoxicity of these degradation products with the aim to save time, laboratory animals, and research funds. A biodegradable polyurethane (PU) foam was subjected to this test method. The PU had soft segments of DL-lactide/epsilon-caprolactone and hard segments synthesized from butanediol and 1,4-butanediiosocyanate. Copolymer foams without urethane segments, consisting of DL-lactide/epsilon-caprolactone, were tested as well. Accumulated degradation products were collected by degrading the foams in distilled water at 60 degrees C up to 52 weeks. Cell-culture medium was prepared from powder medium with this water. In different tests the cytotoxicity of this medium was established. The first signs of cytotoxicity were observed after 3-5 weeks of degradation. This accounts for both materials and reestablishes the good short-term biocompatibility of these materials. The PU showed more toxicity toward the end stages of degradation in comparison with the copolymer. This is probably related to the accumulation of degradation products of the urethane segments. In the in vivo situation the degradation of the PU and the metabolism and excretion of degradation products may differ. Therefore, long-term in vivo studies will have to establish whether these in vitro results are representative for the in vivo behavior of the degrading PU.

Hydrolytic Degradation of Ricinoleic-Sebacic-Ester-Anhydride Copolymers

The degradation process of poly(ricinoleic-co-sebacic-ester-anhydride)s in buffer solution was investigated by following the composition of the degradation products released into the degradation medium and the degraded polymer. The first week of degradation was characterized by the hydrolysis of the anhydride bonds and significant release of sebacic acid (SA). The remaining oligoesters of SA and ricinoleic acid (RA) degraded into shorter oligoesters composed of RA ester dimers, trimers, and tetramers as well as dimers of RA-SA. To confirm and determine the hydrolytic behavior of the degradation products, short oligoesters of sebacic and ricinoleic acid were synthesized and degraded. It was established that during the hydrolysis under physiological conditions the degradation products have a composition and water absorption similar to those of the synthesized oligoesters.

Prevailing mechanisms of the hydrolytic degradation of oligo( d, l-lactide)-grafted dextrans

The predominant mechanism of the hydrolytic degradation of oligo( d, l-lactide)-grafted dextrans in phosphate buffer was followed by quantifying both released dextran and lactic acid from the copolymers. The studied amphiphilic copolymers, with well-defined structure, exhibited various oligo( d, l-lactide) weight fractions ( F OLA) while having a quite high extent of free hydroxyl groups (>90%). Depending on their F OLA, oligo( d, l-lactide)-grafted dextrans were soluble either in water or in organic solvents (THF, toluene, …) and different prevailing mechanisms of hydrolytic degradation were observed. The copolymer soluble in THF, with longer oligo( d, l-lactide) grafts and higher F OLA, was found to degrade via a particular mechanism by which the greatest part of dextran was released into buffer medium during the first two weeks of degradation. During the initial stage of degradation, the hydrophilicity of dextran backbone was considered to be the main driving force for the hydrolytic cleavage of the ester linkage between backbone and grafts. Released oligo( d, l-lactide) grafts were found to be degraded via chain-end degradation or random degradation depending on their solubility in buffer medium. In case of water-soluble copolymers with shorter oligo( d, l-lactide) grafts and lower F OLA, the chain-end degradation was exclusively observed.

Hydraulic Permeability of Polyglycolic Acid Scaffolds as a Function of Biomaterial Degradation

Using a simple experimental setup, the hydraulic permeability of fibrous nonwoven polyglycolic acid (PGA) scaffolds is studied after different degradation durations in PBS. The hydraulic permeability of the scaffolds increased with the degradation time. After being incubated for about 4 weeks, the permeability of the scaffold begins to drop. It is noted that the PGA scaffold apparently begins to contract and cannot maintain its original shape after 4 weeks of degradation. These results underpin the understanding of the biotransport processes in the scaffolds during tissue engineering experiments.