Novel,simple and reproducible method for preparation of composite hierarchal porous structure scaffolds

Demand to develop a simple and adaptable method for preparation the hierarchical porous scaffolds for bone tissue regeneration is ever increasing. This study presents a novel and reproducible method for preparing the scaffolds with pores structure spanning from nano, micro to macro scale. A macroporous Sr-Hardystonite (Sr–Ca₂ZnSi₂O₇, Sr–HT) scaffold with the average pore size of ~ 1200 μm and porosity of ~ 95% was prepared using polymer sponge method. The struts of the scaffold were coated with a viscous paste consisted of salt (NaCl) particles and polycaprolactone (PCL) to provide a layer with thickness of ~ 300–800 μm. A hierarchical porous scaffold was obtained with macro, micro and nanopores in the range of 400–900 μm, 1–120 μm and 40–290 nm, after salt leaching process. These scales could be easily adjusted based on the starting foam physical characteristics, salt particle size, viscosity of the paste and salt/PCL weight ratio.     

The effects of loading conditions and specimen environment on the nanomechanical response of canine cortical bone

Bone is a viscoelastic connective tissue composed primarily of mineral and type I collagen, which interacts with water, affecting its mechanical properties. Therefore, both the level of hydration and the loading rate are expected to influence the measured nanomechanical response of bone. In this study, we investigated the influence of three distinct hydration conditions, peak loads and loading/unloading rates on the elastic modulus and hardness of canine femoral cortical bone via nanoindentation. Sections from three canine femurs from multiple regions of the diaphysis were tested for a total of 670 indentations. All three hydration conditions (dry, moist and fully hydrated tissue) were tested at three different loading profiles (a triangular loading profile with peak loads of 600, 800 and 1000 μN at loading/unloading rate of 60, 80 and 100 μN/s, respectively; each test was 20 s in duration). Significant differences were found for both the elastic modulus and hardness between the dry, moist and fully hydrated conditions (p ≤ 0.02). For dry bone, elastic modulus and hardness values were not found to be significantly different between the different loading profiles (p > 0.05). However, in both the moist and fully hydrated conditions, the elastic modulus and hardness were significantly different under all loading profiles (with the exception of the moist condition at the 600- and 800-μN peak load). Given these findings, it is critical to perform nanoindentation of bone under fully hydrated conditions to ensure physiologically relevant results. Furthermore, this work found that a 20-s triangular loading/unloading profile was sufficient to capture the viscoelastic behavior of bone in the 600- to 1000-μN peak load range. Lastly, specific peak load values and loading rates need to be selected based on the structural region for which the mechanical properties are to be measured.     

Crystallization and hardening of Zr-40 at.% Cu thin film metallic glass: Effects of isothermal annealing

Effects of isothermal annealing on structural relaxation, crystallization and mechanical behavior of Zr-40 at.% Cu thin film metallic glass (TFMG) are reported. Two annealing temperatures have been chosen in the supercooled liquid region (ΔT) and one below the glass transition temperature (T_g). During annealing the free volume decreased and nanocrystals nucleated into the matrix. Results show that the nanocrystalline CuZr₂ intermetallic phase precipitates in the glassy matrix with respect to the annealing temperature and duration. When annealed below T_g, the structural relaxation induces a slight improvement of the mechanical properties with a hardness and Young's modulus variation of about 2.5% and 9.0% compared with the as-deposited values. At higher temperatures, it is shown that hardness increases of about 5.5% and 25.0% after a heat treatment of 60 min at 350 °C and 380 °C, respectively. The elastic modulus follows a time dependent increase from ~ 100 GPa (as-deposited) up to ~ 105 GPa after a one-hour annealing at 350 °C and ~ 125 GPa at 380 °C, respectively.     

Sol–gel derived nanoscale bioactive glass (NBG) particles reinforced poly(ε-caprolactone) composites for bone tissue engineering

This study investigated the effect of the addition of sol–gel derived nanoscale bioactive glass (NBG) particles on the mechanical properties and biological performances of PCL polymer, in order to evaluate the potential applications of PCL/NBG composites for bone tissue regeneration. Regardless of the NBG contents (10, 20, and 30 wt.%), the NBG particles, which were synthesized through the sol–gel process using polyethylene glycol (PEG) polymer as a template, could be uniformly dispersed in the PCL matrix, while generating pores in the PCL/NBG composites. The elastic modulus of the PCL/NBG composites increased remarkably from 89 ± 11 MPa to 383 ± 50 MPa with increasing NBG content from 0 to 30 wt.%, while still showing good ultimate tensile strength in the range of 15–19 MPa. The hydrophilicity, water absorption and degradation behavior of the PCL/NBG composites were also enhanced by the addition of the NBG particles. Furthermore, the PCL/NBG composite with a NBG content of 30 wt.% showed significantly enhanced in vitro bioactivity and cellular response compared to those of the pure PCL.     

Effect of particle size on the in vitro bioactivity,hydrophilicity and mechanical properties of bioactive glass-reinforced polycaprolactone composites

Polycaprolactone (PCL) composite films containing 5 wt.% bioactive glass (BG) particles of different sizes (6 μm, 250 nm, < 100 nm) were prepared by solvent casting methods. The ultra-fine BG particles were prepared by high-energy mechanical milling of commercial 45S5 Bioglass® particles. The characteristics of bioactive glass particles were studied by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD) methods. In vitro bioactivity of the PCL/BG composite films was evaluated through immersion in the simulated body fluid (SBF). The films were analyzed by FE-SEM, energy dispersive spectrometry (EDS), XRD, and atomic force microscopy (AFM). The mechanical properties of highly-porous PCL/BG composites were examined on cylindrical specimens under quasi-static compression load. It was found that partial crystallization of amorphous BG particles during a prolonged mechanical milling occurred and calcium silicate (CaSiO₃) and sodium calcium silicate (Na₂CaSiO₄) phases were formed. The introduction of submicron BG particles (250 nm) was shown to improve the bioactivity of PCL films. In contrast to BG microparticles, the submicron BG particles were distributed on the film surfaces, providing a high surface exposure to SBF with an improved nanotopography. A notable increase in the stiffness and elastic modulus of the composite was also obtained. As compared to submicron BG particles, lower bioactivity and elastic modulus were acquired for PCL/BG nanoparticles. It was also shown that in spite of high specific surface area of the nanoparticles, partial crystallization during mechanical milling and agglomeration of the nanoparticles during processing decrease the bioactivity, hydrophilicity and mechanical response of the BG-reinforced PCL composites.     

Modification of porous calcium phosphate surfaces with different geometries of bioactive glass nanoparticles

In this study, the effects of bioactive glass nanoparticles' (nBGs) size and shape incorporated into hydroxyapatite/β-tricalcium phosphate (BCP) scaffolds were investigated. We prepared a highly porous (> 85%) BCP scaffold and coated its surface with a nanocomposite layer consisted of polycaprolactone (PCL) and rod (~ 153 nm in height and ~ 29 nm in width) or spherical (~ 33 nm and 64 nm in diameter) nBGs. Osteogenic gene expression by primary human osteoblast-like cells (HOB) was investigated using quantitative real time polymerase chain reaction (q-RT-PCR). We demonstrated for the first time that in vitro osteogenesis is dramatically affected by the shape of the nBGs, whereby rod shaped nBGs showed the most significant osteogenic induction, compared to spherical particles (regardless of their size). Importantly, the good biological effect observed for the rod shaped nBGs was coupled by a marked increase in the modulus (~ 48 MPa), compressive strength (~ 1 MPa) and failure strain (~ 6%), compared to those for the BCP scaffolds (~ 4 MPa, ~ 1 MPa and ~ 0.5% respectively). The findings of this study demonstrated that the shape of the nBGs is of significant importance when considering bone regeneration.     

Mechanical properties of conventional and nanostructured plasma sprayed alumina coatings

The hardness and the elastic modulus measured by microindentation of three different types of plasma sprayed alumina coatings have been compared. Usually, such coatings present porosity and heterogeneity which affect the measurement of the mechanical properties. To take such effects into account along with the indentation size effect which is relevant to all hardness studies, the Proportional Specimen Resistance model is applied. The three alumina coatings show closely similar mechanical properties at indentation loads exceeding 1 N, i.e., macrohardness around 5.7 GPa, indentation size effect parameter around 5.5 MPa mm and elastic modulus around 160 GPa. For loads below 1 N, the extrapolated values of the macrohardness of crushed and agglomerated alumina coatings increased to 8.5 GPa, while the indentation size effect parameter has the same value, and the elastic modulus increased to 320 GPa. However, no significant change in the measured values of hardness and the elastic modulus of the nanostructured alumina coating has been observed. This result is attributed to porosity and the bimodal microstructure of the nanostructured coating where a semimolten phase coexists along with the fully molten phases.     

Mechanical properties and microstructure of spark plasma sintered nanostructured p-type SiGe thermoelectric alloys

SiGe based thermoelectric (TE) materials have been employed for the past four decades for power generation in radio-isotope thermoelectric generators (RTG). Recently “nanostructuring” has resulted in significantly increasing the figure-of-merit (ZT) of both n and p-type of SiGe and thus nanostructured Si₈₀Ge₂₀ alloys are evolving as a potential replacement for their conventional bulk counterparts in designing efficient RTGs. However, apart from ZT, their mechanical properties are equally important for the long term reliability of their TE modules. Thus, we report the mechanical properties of p-type nanostructured Si₈₀Ge₂₀ alloys, which were synthesized employing spark plasma sintering of mechanically alloyed nanopowders of its constituent elements with 1.2% boron doping. Nanostructured p-type Si₈₀Ge₂₀ alloys exhibited a hardness of ~ 9 ± 0.1 GPa, an elastic modulus of ~ 135 ± 1.9 GPa, a compressive strength of 108 ± 0.2 MPa, and fracture toughness of ~ 1.66 ± 0.04 MPa√m with a thermal shock resistance value of 391 ± 21 Wm^− 1. This combination of good mechanical properties coupled with higher reported ZT of nanostructured p-type Si₈₀Ge₂₀ alloys are rendered to be a potential material for power generation applications, compared to its bulk counterpart.     

Synthesis of aligned porous poly(ε-caprolactone) (PCL)/hydroxyapatite (HA) composite microspheres

We synthesized poly(ε-caprolactone) (PCL)/hydroxyapatite (HA) composite microspheres with an aligned porous structure and evaluated their potential applications in bone tissue engineering. A range of HA particles (0, 5, 10 and 20 wt.% in relation to the PCL polymer) were added to a PCL solution in order to improve the biocompatibility of the porous PCL/HA composite microspheres. All the synthesized microspheres showed that the HA particles were distributed well in the PCL matrix, while preserving their aligned porous structure. The average size of the PCL/HA composite microspheres increased from 62 ± 7 to 179 ± 95 μm with increasing HA content from 0 to 20 wt.%. The incorporation of the HA particles to the PCL polymer led to a considerable improvement in in vitro bioactivity, which was assessed by immersing the PCL/HA composite microspheres in simulated body fluid (SBF). A number of apatite crystals could be precipitated on the surface of the aligned porous PCL/HA composite microspheres after soaking in the SBF for 7 days.     

Quantitative measurements of small scaled grain sliding in ultra-fine grained Al–Zn alloys produced by friction stir processing

An Al-15 wt.% Zn alloy was processed by friction stir processing to produce grain sizes of ~ 0.5 μm, ~ 1 μm, and ~ 2 μm. A simple and effective method was developed to determine the true strain by scribing marker lines with scaled division using focused ion beam micromachining prior to deformation. The “microscopic” grain boundary sliding, with displacements of adjacent grains of the order of a nanometer, can easily be detected by the proposed technique, providing a surface analysis with high accuracy that could be used to observe the changes in relief with increasing strains. Moreover, the occurrence of grain boundary sliding at room temperature was considered a major cause for higher strain rate sensitivity in fine-grained Al–Zn alloys.     

Mechanically induced self-propagating reaction and consequent consolidation for the production of fully dense nanocrystalline Ti55C45 bulk material

We employed a high-energy ball mill for the synthesis of nanograined Ti₅₅C₄₅ powders starting from elemental Ti and C powders. The mechanically induced self-propagating reaction that occurred between the reactant materials was monitored via a gas atmosphere gas-temperature-monitoring system. A single phase of NaCl-type TiC was obtained after 5 h of ball milling. To decrease the powder and grain sizes, the material was subjected to further ball milling time. The powders obtained after 200 h of milling possessed spherical-like morphology with average particle and grain sizes of 45 μm and 4.2 nm, respectively. The end-products obtained after 200 h of ball milling time, were then consolidated into full dense compacts, using hot pressing and spark plasma sintering at 1500 and 34.5 MPa, with heating rates of 20 °C/min and 500 °C/min, respectively. Whereas hot pressing of the powders led to severe grain growth (~ 436 nm in diameter), the as-spark plasma sintered powders maintained their nanograined characteristics (~ 28 nm in diameter). The as-synthesized and as-consolidated powders were characterized, using X-ray diffraction, high-resolution electron microscopy, and scanning electron microscopy. The mechanical properties of the consolidated samples obtained via the hot pressing and spark plasma sintering techniques were characterized, using Vickers microhardness and non-destructive testing techniques. The Vickers hardness, Young's modulus, shear modulus and fracture toughness of as-spark plasma sintered samples were 32 GPa, 358 GPa, 151 GPa and 6.4 MPa·m^1/2, respectively. The effects of the consolidation approach on the grain size and mechanical properties were investigated and are discussed.     

Synthesis of poly(ε-caprolactone)/hydroxyapatite nanocomposites using in-situ co-precipitation

Hybrid poly(ε-caprolactone) (PCL)/hydroxyapatite(HA) nanocomposites with various HA contents (0, 10, 20, 30 wt.%) were synthesized using an in-situ co-precipitation method. All nanocomposites prepared contained elongated HA nanocrystals dispersed uniformly in the PCL matrix without severe agglomeration. The tensile strength decreased from 13.5 ± 0.4 to 10.2 ± 0.3 MPa with increasing the HA content from 0 to 30 wt.%, whereas the elastic modulus increased from 85 ± 4.2 to 183 ± 6.6 MPa. In addition, the ALP activity was increased remarkably due to the presence of bioactive HA nanocrystals within the composites. The nanocomposite containing 30 wt.% HA showed a higher elastic modulus and ALP activity than the conventional PCL/HA composite with an initial HA content of 30 wt.%. This was attributed to the nanoscale hybridization of the HA nanocrystals without significant agglomeration.     

Microstructure,thermooxidation and mechanical behavior of a novel highly linear,vitamin E stabilized,UHMWPE

A novel, vitamin E-stabilized, medical grade ultra-high molecular polyethylene, MG003 (DSM Biomedical; The Netherlands), has been very recently introduced for use in total joint replacements. This homopolymer resin features average molecular weight similar to that of conventional GUR 1050 resin (5.5–6*10⁶ g/mol), but a higher degree of linearity. The aim of this study was to characterize the microstructure, thermal and thermooxidation properties as well as the mechanical behavior of this novel MG003 resin before and after gamma irradiation in air to 90 kGy. For this purpose, a combination of experimental techniques were performed including differential scanning calorimetry (DSC), thermogravimetry (TG), transmission electron microscopy (TEM), X-Ray Diffraction, electron paramagnetic resonance (EPR), and uniaxial tensile tests. As-consolidated MG003 materials exhibited higher crystalline contents (~ 62%), transition temperatures (~ 140 °C), crystal thickness (~ 36 nm), yield stress (~ 25 MPa) and elastic modulus (~ 400 MPa) than GUR 1050 controls (55%, 136 °C, 27 nm, 19 MPa, and 353 MPa, respectively). Irradiation produced similar changes in both MG003 and GUR 1050 materials, specifically increased crystallinity (63% and 60%, respectively), crystal thickness (39 nm and 30 nm), yield stress (27 MPa and 21 MPa), but, above of all, loss of elongation to breakage (down to 442 and 469%, respectively). Thermogravimetric and EPR results suggest comparable susceptibilities to oxidation for both MG003 and GUR 1050 polyethylenes. Based on the present findings, MG003 appears as a promising alternative medical grade polyethylene and it may satisfactorily contribute to the performance of total joint replacements.     

The synthesis and characterization of a novel biodegradable and electroactive polyphosphazene for nerve regeneration

Conductive polymers have been of great interest to the biopharmaceutical industry because of their cell adhesion and proliferation. In this paper, a novel electrically-conductive and biodegradable polyphosphazene polymer containing parent aniline pentamer (PAP) and glycine ethyl ester (GEE) as side chains was synthesized through a nucleophilic substitution reaction for its potential application in nerve regeneration. The electrical conductivity of the polymer was ~ 2 × 10^? 5 S/cm in the semiconducting region upon preliminarily protonic-doped experiment. Degradation studies carried out in phosphate-buffered saline at 37 °C showed a mass loss of ~ 50% after 70 days. In vitro cytotoxicity to the RSC96 Schwann cells was evaluated using the cell viability assay. The polymer exhibited no cytotoxicity, indicating that such a polyphosphazene polymer has potential as scaffold material in tissue engineering for peripheral nerve regeneration or other biomedical devices that require electroactivity.     

Cytocompatibility,degradation, mechanical property retention and ion release profiles for phosphate glass fibre reinforced composite rods

Fibre reinforced composites have recently received much attention as potential bone fracture fixation applications. Bioresorbable composites based on poly lactic acid (PLA) and phosphate based glass fibre were investigated according to ion release, degradation, biocompatibility and mechanical retention profiles. The phosphate based glass fibres used in this study had the composition of 40P₂O₅–24MgO–16CaO–16Na₂O–4Fe₂O₃ in mol% (P40). The degradation and ion release profiles for the composites showed similar trends with the amount of sodium and orthophosphate ions released being greater than the other cations and anions investigated. This was attributed to low Dietzal's field strength for the Na⁺ in comparison with Mg^2 + and Ca^2 + and breakdown of longer chain polyphosphates into orthophosphate ions. P40 composites exhibited good biocompatibility to human mesenchymal stem cells (MSCs), which was suggested to be due to the low degradation rate of P40 fibres. After 63 days immersion in PBS at 37 °C, the P40 composite rods lost ~ 1.1% of mass. The wet flexural, shear and compressive strengths for P40 UD rods were ~ 70%, ~ 80% and ~ 50% of their initial dry values after 3 days of degradation, whereas the flexural modulus, shear and compressive strengths were ~ 70%, ~ 80%, and ~ 65% respectively. Subsequently, the mechanical properties remained stable for the duration of the study at 63 days. The initial decrease in mechanical properties was attributed to a combination of the plasticisation effect of water and degradation of the fibre–matrix interface, with the subsequent linear behaviour being attributed to the chemical durability of P40 fibres. P40 composite rods showed low degradation and ion release rates, good biocompatibility and maintained mechanical properties similar to cortical bone for the duration of the study. Therefore, P40 composite rods have huge potential as resorbable intramedullary nails or rods.     

Subcritical CO2 sintering of microspheres of different polymeric materials to fabricate scaffolds for tissue engineering

The aim of this study was to use CO₂ at sub-critical pressures as a tool to sinter 3D, macroporous, microsphere-based scaffolds for bone and cartilage tissue engineering. Porous scaffolds composed of ~ 200 μm microspheres of either poly(lactic-co-glycolic acid) (PLGA) or polycaprolactone (PCL) were prepared using dense phase CO₂ sintering, which were seeded with rat bone marrow mesenchymal stromal cells (rBMSCs), and exposed to either osteogenic (PLGA, PCL) or chondrogenic (PLGA) conditions for 6 weeks. Under osteogenic conditions, the PLGA constructs produced over an order of magnitude more calcium than the PCL constructs, whereas the PCL constructs had far superior mechanical and structural integrity (125 times stiffer than PLGA constructs) at week 6, along with twice the cell content of the PLGA constructs. Chondrogenic cell performance was limited in PLGA constructs, perhaps as a result of the polymer degradation rate being too high. The current study represents the first long-term culture of CO₂-sintered microsphere-based scaffolds, and has established important thermodynamic differences in sintering between the selected formulations of PLGA and PCL, with the former requiring adjustment of pressure only, and the latter requiring the adjustment of both pressure and temperature. Based on more straightforward sintering conditions and more favorable cell performance, PLGA may be the material of choice for microspheres in a CO₂ sintering application, although a different PLGA formulation with the encapsulation of growth factors, extracellular matrix-derived nanoparticles, and/or buffers in the microspheres may be advantageous for achieving a more superior cell performance than observed here.     

Flexible polymer microtubes and microchannels via electrospinning

Here we report an approach to fabricate flexible polymer self standing films embedded with continuous aligned microtubes/microchannels via electrospinning. The scheme is to wash the electrospun fibers selectively to form either microtubes/microchannels. Optical microscope (OM) and Scanning electron microscope images are evident for the well aligned microtubes and microchannels respectively with a diameter of ~ 8 μm and a length of ~ 4 cm. Meniscus of tetrahydrofuran in the microtubes can be observed explicitly in the OM images. Mutually perpendicular microtubes are also fabricated on a polymer film. Angular distribution of aligned microstructures indicates the standard deviation is not more than 1°. These tubes/channels can be potential for tissue engineering as they could provide a directional template for the growth when a biodegradable polymer such as Poly(vinylalcohol) is used.     

Effects of sintering temperature on morphology and mechanical characteristics of 3D printed porous titanium used as dental implant

Porous titanium samples were manufactured using the 3D printing and sintering method in order to determine the effects of final sintering temperature on morphology and mechanical properties. Cylindrical samples were printed and split into groups according to a final sintering temperature (FST). Irregular geometry samples were also printed and split into groups according to their FST. The cylindrical samples were used to determine part shrinkage, in compressive tests to provide stress-strain data, in microCT scans to provide internal morphology data and for optical microscopy to determine surface morphology. All of the samples were used in microhardness testing to establish the hardness. Below 1100 °C FST, shrinkage was in the region of 20% but increased to approximately 30% by a FST of 1300 °C. Porosity varied from a maximum of approximately 65% at the surface to the region of 30% internally. Between 97 and 99% of the internal porosity is interconnected. Average pore size varied between 24 μm at the surface and 19 μm internally. Sample hardness increased to in excess of 300 HV0.05 with increasing FST while samples with an FST of below 1250 °C produced an elastic–brittle stress/strain curve and samples above this displayed elastic–plastic behaviour. Yield strength increased significantly through the range of sintering temperatures while the Young's modulus remained fairly consistent.     

Lovastatin release from polycaprolactone coated β-tricalcium phosphate: Effects of pH,concentration and drug–polymer interactions

The approach of local drug delivery from polymeric coating is currently getting significant attention for both soft and hard tissue engineering applications for sustained and controlled release. The chemistry of the polymer and the drug, and their interactions influence the release kinetics to a great extent. Here, we examine lovastatin release behaviour from polycaprolactone (PCL) coating on β-tricalcium phosphate (β-TCP). Lovastatin was incorporated into biodegradable water insoluble PCL coating. A burst and uncontrolled lovastatin release was observed from bare β-TCP, whereas controlled and sustained release was observed from PCL coating. A higher lovastatin release was observed pH 7.4 as compared to pH 5.0. Effect of PCL concentration on lovastatin release was opposite at pH 7.4 and 5.0. At pH 5.0 lovastatin release was decreased with increasing PCL concentration, whereas release was increased with increasing PCL concentration at pH 7.4. High Ca^2 + ion concentration due to high solubility of β-TCP and degradation of PCL coating were observed at pH 5.0 compared to no detectable Ca^2 + ion release and visible degradation of PCL coating at pH 7.4. The hydrophilic–hydrophobic and hydrophobic–hydrophobic interactions between lovastatin and PCL were found to be the key factors controlling the diffusion dominated release kinetics of lovastatin from PCL coating over dissolution and degradation processes. Understanding the lovastatin release chemistry from PCL will be beneficial for designing drug delivery devices from polymeric coating or scaffolds.     

Modification of chloromethylated polystyrene with 2-mercabtobenzothiazole for application as a new sorbent for preconcentration and determination of Ag+ from different matrices

Chloromethylated polystyrene polymer (CMSP) modified with 2-mercabtobenzothiazole (MBT) has been developed for the selective separation and/or preconcentration of silver. The modified polymer (CMS-MBT) was characterized by elemental analysis and IR spectra. Batch and column modes were applied. The newly designed polymer quantitatively sorbed Ag⁺ at pH 2 when the flow rate is 5 ml min^?1. The maximum sorption capacity was 0.493 mmol g^?1 while the preconcentration factor was 250 for Ag⁺. The detection limit was 8 ng ml^?1. The desorption was effective with 5 ml of 2 mol l^?1 HNO₃ prior to detection using AAS. The modified polymer was highly ion-selective in nature even in the presence of large concentrations of electrolytes or organic media, with a preconcentrating ability for Ag⁺. The utility of the modified polymer to synthetic and drugs samples showed RSD values of <3% reflecting its accuracy and reproducibility.