Membrane-Free Lateral Flow Assay with the Active Control of Fluid Transport for Ultrasensitive Cardiac Biomarker Detection.

Membrane-based lateral flow immunoassays (LFAs) have been employed as early point-of-care (POC) testing tools in clinical settings. However, the varying membrane properties, uncontrollable sample transport in LFAs, visual readout, and required large sample volumes have been major limiting factors in realizing needed sensitivity and desirable precise quantification. Addressing these challenges, we designed a membrane-free system in which the desirable three-dimensional (3D) structure of the detection zone is imitated and used a small pump for fluid flow and fluorescence as readout, all the while maintaining a one-step assay protocol. A hydrogel-like protein-polyelectrolyte complex (PPC) within a polyelectrolyte multilayer (PEM) was developed as the test line by complexing polystreptavidin (pSA) with poly(diallyldimethylammonium chloride) (PDDA), which in turn was layered with poly(acrylic acid) (PAA) resulting in a superior 3D streptavidin-rich test line. Since the remainder of the microchannel remains material-free, good flow control is achieved, and with the total volume of 20 µL, 7.5-fold smaller sample volumes can be used in comparison to conventional LFAs. High sensitivity with desirable reproducibility and a 20 min total assay time were achieved for the detection of NT-proBNP in plasma with a dynamic range of 60-9000 pg·mL-1 and a limit of detection of 56 pg·mL-1 using probe antibody-modified fluorescence nanoparticles. While instrument-free visual detection is no longer possible, the developed lateral flow channel platform has the potential to dramatically expand the LFA applicability, as it overcomes the limitations of membrane-based immunoassays, ultimately improving the accuracy and reducing the sample volume so that finger-prick analyses can easily be done in a one-step assay for analytes present at very low concentrations.

PDADMAC/Alginate-Coated Gold Nanorod For Eradication of Staphylococcus Aureus Biofilms.

Introduction: Over 75% of clinical microbiological infections are caused by bacterial biofilms that grow on wounds or implantable medical devices. This work describes the development of a new poly(diallyldimethylammonium chloride) (PDADMAC)/alginate-coated gold nanorod (GNR/Alg/PDADMAC) that effectively disintegrates the biofilms of Staphylococcus aureus (S. aureus), a prominent pathogen responsible for hospital-acquired infections. Methods: GNR was synthesised via seed-mediated growth method, and the resulting nanoparticles were coated first with Alg and then PDADMAC. FTIR, zeta potential, transmission electron microscopy, and UV-Vis spectrophotometry analysis were performed to characterise the nanoparticles. The efficacy and speed of the non-coated GNR and GNR/Alg/PDADMAC in disintegrating S. aureus-preformed biofilms, as well as their in vitro biocompatibility (L929 murine fibroblast) were then studied. Results: The synthesised GNR/Alg/PDADMAC (mean length: 55.71 ± 1.15 nm, mean width: 23.70 ± 1.13 nm, aspect ratio: 2.35) was biocompatible and potent in eradicating preformed biofilms of methicillin-resistant (MRSA) and methicillin-susceptible S. aureus (MSSA) when compared to triclosan, an antiseptic used for disinfecting S. aureus colonisation on abiotic surfaces in the hospital. The minimum biofilm eradication concentrations of GNR/Alg/PDADMAC (MBEC50 for MRSA biofilm = 0.029 nM; MBEC50 for MSSA biofilm = 0.032 nM) were significantly lower than those of triclosan (MBEC50 for MRSA biofilm = 10,784 nM; MBEC50 for MRSA biofilm 5967 nM). Moreover, GNR/Alg/PDADMAC was effective in eradicating 50% of MRSA and MSSA biofilms within 17 min when used at a low concentration (0.15 nM), similar to triclosan at a much higher concentration (50 µM). Disintegration of MRSA and MSSA biofilms was confirmed by field emission scanning electron microscopy and confocal laser scanning microscopy. Conclusion: These findings support the potential application of GNR/Alg/PDADMAC as an alternative agent to conventional antiseptics and antibiotics for the eradication of medically important MRSA and MSSA biofilms.

Irradiation Behavior of Analgesic and Nonsteroidal Anti-Inflammatory Drug-Loaded UHMWPE for Joint Replacement.

Local delivery of pain medication can be a beneficial strategy to address pain management after joint replacement, as it can decrease systemic opioid usage, leading to less side and long-term effects. In this study, we used ultrahigh molecular weight polyethylene (UHMWPE), commonly employed as a bearing material for joint implants, to deliver a wide set of analgesics and the nonsteroidal anti-inflammatory drug tolfenamic acid. We blended the drugs with UHMWPE and processed the blend by compression molding and sterilization by low-dose gamma irradiation. We studied the chemical stability of the eluted drugs, drug elution, tensile properties, and wear resistance of the polymer blends before and after sterilization. The incorporation of bupivacaine hydrochloride and tolfenamic acid in UHMWPE resulted in either single- or dual-drug loaded materials that can be sterilized by gamma irradiation. These compositions were found to be promising for the development of clinically relevant drug-eluting implants for joint replacement.

Graphene oxide-DNA/graphene oxide-PDDA sandwiched membranes with neuromorphic function.

The behavior of polyelectrolytes in confined spaces has direct relevance to the protein mediated ion transport in living organisms. In this paper, we govern lithium chloride transport by the interface provided by polyelectrolytes, polycation, poly(diallyldimethylammonium chloride) (PDDA) and, polyanion, double stranded deoxyribonucleic acid (dsDNA), in confined graphene oxide (GO) membranes. Polyelectrolyte-GO interfaces demonstrate neuromorphic functions that were successfully applied with nanochannel ion interactions contributed, resulting in ion memory effects. Excitatory and inhibitory post-synaptic currents were tuned continuously as the number of pulses applied increased accordingly, increasing decay times. Furthermore, we demonstrated the short-term memory of a trained vs untrained device in computation. On account of its simple and safe production along with its robustness and stability, we anticipate our device to be a low dimensional building block for arrays to embed artificial neural networks in hardware for neuromorphic computing. Additionally, incorporating such devices with sensing and actuating parts for a complete feedback loop produces robotics with its own ability to learn by modifying actuation based on sensing data.

Time-Resolved Killing of Individual Bacterial Cells by a Polycationic Antimicrobial Polymer.

Polycationic polymers are widely studied antiseptics, and their efficacy is usually quantified by the solution concentration required to kill a fraction of a population of cells (e.g., by Minimum Bactericidal Concentration (MBC)). Here we describe how the response to a polycationic antimicrobial varies greatly among members of even a monoclonal population of bacteria bathed in a single common antimicrobial concentration. We use fluorescence microscopy to measure the adsorption of a labeled cationic polymer, polydiallyldimethylammmonium chloride (PDADMAC, Mw ≈ 4 × 105 g mol-1) and the time course of cell response via a cell permeability indicator for each member of an ensemble of either Escherichia coli, Staphylococcus aureus, or Pseudomonas aeruginosa cells. This is a departure from traditional methods of evaluating synthetic antimicrobials, which typically measure the overall response of a collection of cells at a particular time and therefore do not assess the diversity within a population. Cells typically die after they reach a threshold adsorption of PDADMAC, but not always. There is a substantial time lag of about 5-10 min between adsorption and death, and the time to die of an individual cell is well correlated with the rate of adsorption. The amount adsorbed and the time-to-die differ among species but follow a trend of more adsorption on more negatively charged species, as expected for a cationic polymer. The study of individual cells via time-lapse microscopy reveals additional details that are lost when measuring ensemble properties at a particular time.

The Isothermal Melting Kinetics of Ultra-High Molecular Weight Polyethylene Crystals.

The isothermal melting behaviors of ultra-high molecular weight polyethylene (UHMWPE) with different entangled states (i.e., nascent and melt-crystallized samples) are studied. For two kinds of UHMWPE samples, the result shows that the relative content of survived crystals (Xs) exponentially decreases with time and reaches a constant value. It is suggested that such a melting behavior is related to the observed nonlinear growth of crystals induced by the kinetically rejected entanglements accumulated at the growth front. Additionally, the exponential decay of Xs with time provides a characteristic melting time (τ) for the melting process. Compared to the melt-crystallized UHMWPE, the τ value of nascent UHMWPE is generally longer even in a higher temperature range, which is mainly because the former has a larger entanglement density difference. Furthermore, these observations demonstrate that UHMWPEs with different entangled states have an analogous melting mechanism since they exhibit a similar melting activation energy (≈1300 kJ mol-1).

Lipid index to quantify the absorbed lipids in retrieved UHMWPE components of joint arthroplasty.

BACKGROUND: The ultra-high molecular weight polyethylene (UHMWPE) component of artificial joints is one of the most important factors affecting the clinical outcomes of joint arthroplasty. Although the possibility of in vivo UHMWPE degradation caused by absorbed lipids has been reported, a quantitative evaluation of this phenomenon has not yet been performed. OBJECTIVE: This study aimed to establish the lipid index (LI) as a quantitative indicator of the amount of absorbed lipids and the first step to quantify their effects on UHMWPE. METHODS: The LI was defined using the infrared spectrum obtained with a Fourier-transform infrared spectrophotometer and verified using the retrieved UHMWPE components. RESULTS: The LI was consistent with the amount of extract recovered in reflux extraction with hexane. In addition, the LI could replace lipid extraction for calculating the oxidation index (OI) because the value obtained by subtracting the LI from the OI showed good agreement with the OI obtained after lipid extraction. CONCLUSION: The LI represents the amount of lipids absorbed by UHMWPE and is useful for quantitatively evaluating the effects of lipids on UHMWPE. In addition, the LI enables OI measurements that are unaffected by absorbed lipids without requiring troublesome lipid-extraction procedures.

Bio-inspired copper ion-chelated chitosan coating modified UHMWPE fibers for enhanced interfacial properties of composites.

Ultra-high molecular weight polyethylene (UHMWPE) fibers are broadly applied in lightweight and high-strength composite fiber materials. However, the development of UHMWPE fibers is limited by their smooth and chemically inert surfaces. To address the issues, a modified UHMWPE fibers material has been fabricated through the chelation reaction between Cu2+ and chitosan coatings within the surface of fibers after plasma treatment, which is inspired by the hardening mechanism, a crosslinked network between metal ions and proteins/polysaccharides of the tips and edges in arthropod-specific cuticular tools. The coatings improve the surface wettability and interfacial bonding ability, which are beneficial in extending the application range of UHMWPE fibers. More importantly, compared to the unmodified UHMWPE fiber cloths, the tensile property of the modified fiber cloths is increased by 18.89% without damaging the strength, which is infrequent in modified UHMWPE fibers. Furthermore, the interlaminar shear strength and fracture toughness of the modified fibers laminate are increased by 37.72% and 135.90%, respectively. These improvements can be attributed to the synergistic effects between the surface activity and the tiny bumps of the modified UHMWPE fibers. Hence, this work provides a more straightforward and less damaging idea of fiber modification for manufacturing desirable protective and medical materials.

Characterization of hardness and elastic modulus using nanoindentation and correlation with wear behavior of UHMWPE during uniaxial tension.

UHMWPE is the material of choice for bearing surfaces in total joint arthroplasty making its wear and mechanical properties important factors of contribution in longevity of prosthetic hip/knee implants. In this study, the variation of hardness and elastic modulus with applied load in textured UHMWPE has been investigated. Texture has been induced through uniaxial tension of UHMWPE modifying its microstructure which in turn influences the wear resistance and hence the mechanical properties of the material. Previous studies have shown hardness to be a major factor influencing wear resistance. However, recently, the ratio of hardness (H) to elastic modulus (E) has been recognized as a more influential parameter of wear resistance. The validity of predicting wear resistance using H/E ratio has been examined in this work. Power law variation with load for the bioimplant material UHMWPE has been investigated at different strain levels. It has been observed that power law exponent of 2 can only be achieved at higher load levels. Overall, this work provides an insight into influencing the properties of bioimplant material UHMWPE by modifying the microstructure of the material through inducing texture which ultimately affects the longevity of the prosthetic implants.

Fractional order ATR-FTIR differential spectroscopy for detection of weak bands and assessing the radiation modifications in gamma sterilized UHMWPE.

This study presents a new method for identifying radiation modifications in UHMWPE polymer samples. The method involves using a mathematical technique called fractional order differential transformation on IR spectra obtained through ATR-FTIR spectroscopy. This new method was compared to existing techniques such as FTIR, XRD, and DSC, and it was found to be more sensitive and accurate in detecting radiation-induced changes in the polymer. The study focused on identifying changes in weak IR bands in the UHMWPE samples caused by gamma sterilization while simulating IR spectra using different orders of fractional derivatives and compared them to experimental spectra. It was found that applying a lower order of differentiation was more suitable for identifying radiation-induced changes in the UHMWPE samples. Using this method, they were able to identify specific changes in the gamma irradiated structure, such as the splitting of a single absorption peak into a doublet, which was only present in the 50 kGy irradiated sample. The study also used correlation index analysis, principal component analysis, and hierarchy cluster analysis to analyze the simulated and experimental spectra. These techniques allowed to confirm the effectiveness of the fractional order differential transformation method and to identify the specific regions of the IR spectra that were affected by radiation-induced changes in the UHMWPE samples. Overall, this study presents a new method for identifying radiation-induced changes in UHMWPE polymer samples that is more sensitive and accurate than existing techniques. By identifying these changes, researchers can better understand the effects of gamma sterilization on medical equipment and potentially develop new methods for sterilization that do not damage the equipment.

Identifying differences in the tribological performance of GUR 1020 and GUR 1050 UHMWPE resins associated to pressure × velocity conditions in linear reciprocating sliding tests.

In this work, two commercial UHMWPE (ultra-high molecular weight polyethylene) resins used in orthopedics, GUR 1050 and GUR 1020, were evaluated through linear reciprocating dry friction tests. Average contact pressures (P) of 34 MPa and 50 MPa and sliding velocities (V) of 0.02 m/s and 0.10 m/s were selected to perform tests in four PV conditions. The friction coefficient (COF) with both resins was around 0.18 in average, without significant distinctions by PV; however, a distinction was seen in COF dispersion; it was in the range of 5%-19%, in dependence of the PV condition and resin type. COF with GUR 1020 was more disperse, and it was related to the vulnerability of the resin to undergoing dynamic changes in the intensity of adhesive (higher COF) or abrasive (lower COF) wear mechanisms. Both wear mechanisms are displayed simultaneously, but random changes in intensity may occur during the friction process. Such randomness was associated to the susceptibility to have the structure modified by friction, higher in GUR 1020 than GUR 1050. Concerning wear amount, contact pressure was the most influencing parameter on it. GUR 1020 performed more than 30% inferior than GUR 1050 under contact pressure higher than the yield strength of the material. Under pressures near the material strength, the wear level was in the range of surface roughness and both resins performed equal in average; however, in this case, the dispersion was systematically lower for GUR 1050, evidencing its better tribological stability. It was concluded that analyses on the dispersion of the tribological responses disclosed relevant information on stability related performance. Also, when procedural dependent properties, as such friction and wear, are considered as evaluation parameters, care must be taken to compare results from different tribosystems.

Influence of plane-strain compression on the microstructure and tribological behavior of GUR 1050 UHMWPE.

Ultra-high molecular weight polyethylene (UHMWPE) has been used as a bearing surface in orthopedic implants due to its outstanding physical and mechanical properties. Modifications in the structure of the polymer have a direct effect on its wear. In this work, plane-strain compression in a channel die was applied to induce microstructural changes in specimens of UHMWPE GUR 1050. These structural changes were characterized using a combined approach involving Raman spectroscopy and atomic force microscopy. These qualitative and quantitative characterization resulted in a valuable understanding of the changes in the material microstructure when subjected to plastic deformation. A molecular non-uniform alignment of the UHMWPE molecules, with fragmentation and kinking of polymer lamellae, was observed in the direction of material flow, perpendicular to the compressive load direction, following an inhomogeneous strain field generated by the mechanical compression. The microstructural analyses revealed an increased crystalline content and decreased intermediate phase while amorphous phase content remained unchanged, in all the regions of the deformed specimen. The tribological performance, evaluated by the scratch resistance force, decreased along the material flow direction and increased along the load direction in the deformed polymer compared to that of the uncompressed polymer. Plane-strain compression was able to modify the polymer microstructure, introducing directional anisotropy in its tribological behavior that can impact the wear performance of the material.

Effect of synovial fluid temperature on wear resistance of different polymer acetabular materials.

In order to investigate the effect of frictional heat on the wear resistance characteristics of polymeric acetabular materials, the tribological tests and wear numerical analysis of three common polymer acetabular materials were carried out under different synovial fluid temperatures. The study results show that XLPE and VE-XLPE exhibit superior wear resistance compared to UHMWPE in high-temperature, heavy load environments. The coefficient of friction of three materials gradually decreases as the temperature of the synovial fluid increases. The wear depth and wear volume of the three materials increased with the increase of the temperature of the synovial fluid, and the forms of wear at 46°C and 55°C were mainly adhesive wear and plastic deformation. The higher temperature of the synovial fluid accelerates the oxidative degradation of the material surface and generates oxidation functional groups, which leads to the breakage of C-C bonds in the surface molecular chains under the sliding shear effect, thus reducing the mechanical properties of the material. Specifically, the surface of the polymer material will soften at a higher ambient temperature, mainly due to the decrease of hardness, and then deteriorate in the friction property, and finally increase the wear rate. Ansys results showed that the volume wear of the three materials increased with the increase of synovial fluid temperature, and the trend could be approximately linear. Numerical calculations predict that VE-XLPE has the highest wear of 0.693 mm3 among the three materials at 37°C, followed by XLPE at 0.568 mm3 and UHMWPE with the lowest wear of 0.478 mm3. At higher synovial fluid temperatures (46°C, 55°C), VE-XLPE still has the largest wear volume among the three materials, while XLPE and UHMWPE have similar wear. The wear cloud pictures showed that the maximum wear volume occurred near the edge of the acetabulum.

Facile surface treatment strategy to generate dense lysozyme layer on ultra-high molecular weight polyethylene enabling inhibition of bacterial biofilm formation.

Medical plastics such as those found in endotracheal tubes are widely used in intensive care units for the treatment of critically ill patients. Although commonplace in hospital environment, these catheters are at a high risk of bacterial contamination and have been found responsible for numerous health-care-associated infections. Antimicrobial coatings that can prevent harmful bacterial growth are required to reduce the occurrence of such infections. In this study, we introduce a facile surface treatment strategy that could form antimicrobial coatings on the surface of average medical plastics. The strategy involves treatment of activated surfaces with lysozyme, a natural antimicrobial enzyme presenting in human lacrimal gland secretions which is widely used for wound healing. Using ultra-high molecular weight polyethylene (UHMWPE) as the representative surface, oxygen/argon plasma treatment for 3 min led to the increase of surface roughness and the generation of negatively charged groups, with the zeta potential measured as -94.5 mV at pH 7. The activated surface could accommodate lysozyme with a density of up to 0.3 nmol/cm2 through electrostatic interaction. Antimicrobial activity of the resulting surface (UHMWPE@Lyz) was characterized with Escherichia coli and Pseudomonas sp. strains, and the treated surface significantly inhibited the bacterial colonization and the formation of biofilm compared to the untreated UHMWPE. This method of constructing an effective lysozyme-based antimicrobial coating is a generally applicable, simple and fast process for surface treatment with no adverse solvent and wastes involved.

Preparation and characterization of UHMWPE reinforced with polyester fibers for artificial cervical disc replacement (ACDR).

The purpose of this paper is to report on the preparation and improvement of a biocomposite material made from ultra-high molecular weight polyethylene for the replacement of natural discs. Such replacements are necessary due to intervertebral disc degradation as humans age, which can cause persistent pain due to nerve compression and high friction between vertebrae that can lead to vertebral corrosion. The material was shown to have excellent mechanical properties such as low coefficient of friction, and biocompatibility; however, it degraded with time due to wear failure. Moreover, The wear resistance was related to many factors, such as toughness.In the methodology of the current study, UHMWPE is reinforced with different percent of polyester (2, 4, 6, 8, 10%) to improve the mechanical properties of the polymer disc, thus enhancing its toughness and providing its high bearing ability for the load.The findings revealed that the tensile strength and modulus of elasticity improved by 43.415% and 34.286%, respectively, with the 6% polyester fibers due to the excellent entanglement between the matrix and reinforcing phase. The other mechanical properties, such as flexural strength and modulus, impact strength, fracture toughness, and compression strength, were also enhanced in this study. The highest value at 6% polyester fiber was found to be due to good bonding and adhesion between the polymer and polyester fibers. The Fourier Transformation Spectroscopy (FTIR) showed a shift on some peaks.The originality of this work is that the improvements due to the new bio-composite polymers for artificial implant cervical discs can open many applications in future for these materials.

Oxidation in Retrieved, Never-Irradiated UHMWPE Bearings: What Can We Learn About in Vivo Oxidation?

BACKGROUND: Published analyses of never-irradiated, ethylene oxide (EtO)-sterilized tibial inserts and EtO- and gas plasma (GP)-sterilized acetabular ultra-high molecular weight polyethylene (UHMWPE) retrievals demonstrated minimal UHMWPE in vivo oxidation, whereas another analysis of EtO-sterilized acetabular liners found elevated oxidation linked with in vivo stresses. This study explored whether never-irradiated UHMWPE bearings are (1) oxidized by the in vivo environment, and (2) more likely to oxidize in higher-stress articulations (knee, ankle, shoulder). METHODS: An institutional review board-approved retrieval archive was queried for never-irradiated, EtO- and GP-sterilized UHMWPE bearings received at revision from 2001 to 2021. A total of 193 EtO-sterilized and 112 GP-sterilized conventional UHMWPE retrievals were analyzed (0 to 25 years in vivo; 133 hip, 144 knee, 18 ankle, and 10 shoulder). Retrieved implants were evaluated for in vivo damage and analyzed for trans-vinylene and ketone content by Fourier transform infrared spectroscopy (FTIR). Twelve never-implanted EtO-sterilized tibial knee inserts, (shelf-aged 5 to 19 years) were non-oxidized controls. Mechanical properties of 3 never-implanted and 3 retrieved tibial inserts were evaluated by ASTM Type-V uniaxial tensile testing. Statistical analyses evaluated correlations between time in vivo and oxidation, and compared mean oxidation rates by articulation. RESULTS: Burnishing was the most common clinical damage for all articulations. Eight retrievals exhibited oxidation-related fatigue damage. All retrievals were validated as never-irradiated (median trans-vinylene index [TVI] = 0.000). Maximum ketone oxidation in retrievals correlated with in vivo time (p < 0.001). Thirty-seven percent of retrievals exhibited UHMWPE (subsurface) oxidation, most frequently ankle, knee, and glenoid inserts. Tensile properties differed between retrieved and never-implanted inserts, changing with oxidation. The oxidation rate differed significantly among the articulations (p < 0.001). CONCLUSIONS: This study cohort confirmed the presence of in vivo oxidation in some non-irradiation-sterilized UHMWPE bearings, with higher-stress articulations (knee, ankle, shoulder) showing evidence of oxidation more frequently and having significantly higher oxidation rates than hips. Mechanical properties degraded by oxidation led to fatigue damage in 8 retrievals after a long duration in vivo. CLINICAL RELEVANCE: Conventional EtO- or GP-sterilized UHMWPE bearings are at minimal risk for fatigue damage secondary to oxidation. However, higher stresses and longer time in vivo (more cycles of use) can lead to increased wear, oxidation, and fatigue damage.

Multi-length scale strengthening and cytocompatibility of ultra high molecular weight polyethylene bio-composites by functionalized carbon nanotube and hydroxyapatite reinforcement.

The mechanical properties, such as hardness and elastic modulus, of ultra-high molecular weight polyethylene (UHMWPE) composites for acetabular cup liner are improved by adding hydroxyapatite (HAp) and carbon nanotubes (CNT). However, the weak adhesion of HAp (H) and CNT (C) with UHMWPE (U) limits the enhancement of mechanical properties. Thus, the surface of these reinforcements is silane-treated to improve the adhesion with polymer via Si-O and C=O bonds, as evidenced from spectroscopy techniques. An increased dispersion and interfacial adhesion of functionalized HAp (fH) and CNT (fC) with the polymer matrix is confirmed by nearly two-fold increased reinforcement fraction (Rf: 0.55) of U-10 wt% fHAp-2 wt.% fCNT (U10fH2fC) in comparison to U-10 wt% HAp-2 wt.% CNT (U10H2C). Additionally, Voronoi Tessellation (VT) on SEM micrographs of U10H2C and U10fH2fC revealed the dispersion of functionalized CNTs in U10fH2fC with a center-to-center distance of 0.076 µm, which is 74% higher for unfunctionalized CNT in U10H2C. The multilength scale strengthening of the UHMWPE matrix is confirmed from atomic level modification via functionalization of fillers which effectively adhered to the polymer chain on a micro-scale level. A uniform distribution of CNTs rendered increased crystallinity (+28%) of U10fH2fC, which in turn resulted in significant improvement in bulk mechanical properties (18%, 49%, and 12% increased hardness (148.1 MPa), elastic modulus (3.51 GPa) and tensile elastic modulus (219.8 MPa), respectively) in comparison to that of U10H2C. Functionalized-HAp/CNT reinforced UHMWPE composites maintained its cytocompatibility in the MTT test and fluorescence microscopy, affirming their potential employment as acetabular cup liners for hip joint arthroplasty.

Formation of particulate lipid lyotropic liquid crystalline nanocarriers using a microfluidic platform.

HYPOTHESIS: Non-lamellar lyotropic liquid crystal nanoparticles (LLCNPs) are gaining significant interest in the fields of drug delivery and nanomedicine. Traditional, top-down formulation strategies for LLCNPs are typically low-throughput, can lack controllability and reproducibility in the particle size distribution, and may be unsuitable for loading more fragile therapeutics. The development of a controllable, reproducible, scalable, and high-throughput strategy is urgently needed. EXPERIMENTS: Monoolein (MO)-based LLCNPs with various stabilizers (F127, F108, and Tween 80) and phytantriol (PT)-F127 cubosomes were produced at various flow conditions via a bottom-up method using a microfluidic platform. FINDINGS: This simple enabling strategy was used to formulate LLCNPs with lower polydispersity compared to the traditional top-down homogenization method. Significantly, particle size could be quantitatively controlled by varying the overall flow-rate; a scaling law was identified between nanoparticle mean size and the total flow rate (Q) of meansize∼Q-0.15 for MO cubosomes and meansize∼Q-0.19 for PT cubosomes (at a fixed flow rate ratio). Effective size control was achieved for a range of cubosome formulations involving different lipids and stabilizers. The formulation of stable, drug-loaded cubosomes with high encapsulation efficiency using this method was exemplified using calcein as a model drug. This work will further promote the utilisation of LLCNPs in nanomedicine and facilitate their clinical translation.

Conversion of Polyethylenes into Fungal Secondary Metabolites.

Waste plastics represent major environmental and economic burdens due to their ubiquity, slow breakdown rates, and inadequacy of current recycling routes. Polyethylenes are particularly problematic, because they lack robust recycling approaches despite being the most abundant plastics in use today. We report a novel chemical and biological approach for the rapid conversion of polyethylenes into structurally complex and pharmacologically active compounds. We present conditions for aerobic, catalytic digestion of polyethylenes collected from post-consumer and oceanic waste streams, creating carboxylic diacids that can then be used as a carbon source by the fungus Aspergillus nidulans. As a proof of principle, we have engineered strains of A. nidulans to synthesize the fungal secondary metabolites asperbenzaldehyde, citreoviridin, and mutilin when grown on these digestion products. This hybrid approach considerably expands the range of products to which polyethylenes can be upcycled.