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Purpose: To report a case of solitary fibrous tumor of the orbit in a patient with changes in tumor size and contrast enhancement.Case summary: A 64-year-old male patient presented with dizziness, discomfort on eye movement, anosmia, and proptosis. Orbital computed tomography showed an enhancing mass in the right extraconal space, lateral to the medial rectus and inferior to the superior oblique muscle. The mass appeared to be a cavernous hemangioma and the patient was monitored for changes in mass size and eye movements. After 24 months of follow-up, the mass size and symptoms of right eyelid swelling, proptosis, and diplopia had increased. Excision and biopsy of the mass were performed under general anesthesia. The biopsy confirmed that the mass was a solitary fibrous tumor. The postoperative period was uneventful and no recurrence was observed at 6 months after surgery.Conclusions: Solitary fibrous tumor is a soft tissue tumor that rarely occurs in the orbit, and should be considered in cases with an intraorbital mass accompanied by increased size and changes in contrast enhancement on imaging.

Interface modulation of nickel phosphide (Ni

Phthalate esters (PEs) are the most commonly used plasticizers and one of the endocrine disrupting chemicals (EDCs) which are extensively present in various environment. Therefore, it is important to examine the levels and distribution of phthalates in multimedia environment. This study investigated the seasonal and spatial variation of 14 PEs in air, water, sediments, and fish in the Asan Lake. Asan Lake is one of the largest artificial lakes in Korea, and is surrounded by industrial complex and farmlands. The PEs were found to be present throughout the study area. The mean concentration of total PEs (∑14 PEs) was 3.92–33.09 ng/m3 in air, not detected (n.d.)-2.29 μg/L in water, 3.6–8973 μg/kg dry weight (dw) in sediment, and n.d.-1081 μg/kg dw in fish, respectively. The most frequently detected phthalate in the samples was di(2-ethylhexyl) phthalate (DEHP), and followed by di-n-butyl phthalate (DBP). The concentrations of PEs in water and sediment samples tended to decrease moving downstream of Asan Lake. Bioaccumulation of PEs showed that benthic feeding fish such as crucian carp or skygager contained higher levels of DEHP. Partitioning of DEHP and DBP between water and sediment was calculated using paired sediment/water samples and fugacity fraction (ff). High ff value (ff = 0.89 ± 0.1) of DBP and low ff value of DEHP (ff = 0.24 ± 0.1) confirmed that DEHP is the most abundant PEs in the sediment, and DBP is the second most abundant PEs except DEHP in water. Our results can provide important information of the distribution and behavior of PEs in the lake environment. Keywords: Phthalate esters, DEHP (di(2-ethylhexyl) phthalate), DBP (di-n-butyl phthalate), Sediment-water partitioning, Bioaccumulation, Fugacity fraction

Biomineralization is a promising material synthesis strategy for environmentally benign production of nanostructured metal oxides. An important question is whether biomineralization can be used in the biomimetic synthesis of TiO2 with tunable photocatalytic properties that are conducive to diverse solar energy conversion applications. Here, we report the biomineralization of energy-state-modified TiO2 nanoparticles, where the critical properties closely related to their photocatalytic activity can be manipulated by tailoring the nature of the designer biotemplates. For this purpose, STB1 heptapeptide was employed as a nucleation center to induce TiO2 biomineralization. Three distinctive types of biomolecules (peptide, protein, and phage) were deliberately designed to contain the STB1 nucleation core at different local densities and intermolecular distances. The degree of substitutional nitrogen-doping and the morphology are all subject to the context-dependent differential availability of STB1 in the biomineralization milieu. Phage-induced biomineralization results in TiO2 with modified energy state and wire-like network morphology, which account for significantly enhanced charge dissociation/transport performance and high photocatalytic activity. This is the first study to report that a specific peptide with biomineralizing activity exerts differential impacts on the properties of resulting biomineralization products in a context-dependent manner, and will provide a powerful new strategy for tailoring of material properties via biomineralization.

Cataracts are a disease that is usually caused by aging and involve the irreversible degeneration of the lens material. On the other hand, transient cataracts have also been reported, mainly due to systemic hyperglycemia, which often occurs bilaterally. However, reports of the spontaneous regression of unilaterally occurring cataracts in patients with normal blood glucose levels are rare. Here, we report a rare case of spontaneous regression of unilateral posterior subcapsular cataracts in an adult with normal blood glucose levels.A 42-year-old woman presented with distorted vision in her right eye. The patient was taking medication for diabetes, and her blood sugar level was well-controlled.Upon examination, her uncorrected visual acuity and best-corrected visual acuity were 20/70 in her right eye. Slit lamp microscopy revealed fine, feathery, and streak-like posterior subcapsular opacities. Color fundus photography revealed a star-shaped shadow due to the cataract, and no diabetic retinopathy was observed. Her two hour postprandial glucose level was 115 mg/dL. The patient was diagnosed with posterior subcapsular cataracts, and cataract surgery was planned. The patient was scheduled to visit the clinic again after seven days.Close observation for one week without any intervention.After one week, most of the posterior subcapsular opacities disappeared, and the uncorrected visual acuity and best-corrected visual acuity in the right eye improved to 20/40 and 20/30, respectively.This case report demonstrates that unilateral posterior subcapsular cataracts may spontaneously regress in patients with normal blood glucose levels. Therefore, it is important to check whether cataracts improve spontaneously through short-term close follow-up before planning cataract surgery to avoid unnecessary surgery.

Environmentally friendly ammonia (NH3) decomposition has attracted a lot of interests in recent years to resolve the issue of water eutrophication from a wastewater and achieve a clean H2 storage. Here, we report a novel strategy for solar-driven ammonia decomposition by introducing a highly-activated iron phosphate (FePi) over-layer on the surface of α-Fe2O3 nanorods photoanode (FePi/Fe2O3), and innovatively propose a photoelectrochemical (PEC) ammonia degradation system with enhanced performance. After a facile electrochemical (EC) activation, the FePi over-layer is converted into FeOOH. The EC-activated over-layer provides the efficient active sites for the ammonia adsorption process, which promotes the high catalytic kinetics for ammonia oxidation reaction (AOR). Due to the synergistic effect of the electrocatalytic and the photocatalytic process, the FePi/Fe2O3 exhibits the enhanced PEC AOR performance, which competes with water oxidation reaction (WOR). Comparing to the initial concentration of ammonia, the FePi/Fe2O3 achieves a 54.4% ammonia degradation rate within 3 h at 1.23 V vs. reversible hydrogen electrode (RHE) under 1 sun illumination, which demonstrates the reliable ammonia decomposition performance. This study confirms that it is feasible to achieve PEC ammonia decomposition in an aqueous solution without chloride mediators and provides a promising strategy for the harmless treatment of ammonia wastewater.

In this study, a solution-processable compact vanadium oxide (V2O5) film with a globular nanoparticulate structure is introduced to the hole transport layer (HTL) of polymer bulk-heterojunction based solar cells comprised of PTB7:PC70BM by using a facile metal-organic decomposition method to replace the conventionally utilized poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). For this, a biocompatible structure-determining agent, polyethylene glycol (PEG, Mn 300), is used as an additive in the precursor to form the nanoparticulate compact V2O5 (hereafter referred to as NP-V2O5) film, which possesses an outstandingly smooth surface morphology. The introduction of NP-V2O5 HTL via the solution process with a neutral pH condition successfully improved the stability by preventing the decomposition of indium tin oxide (ITO) glass and the penetration of heavy-metal components and moisture, which are considered as the crucial drawbacks of using PEDOT:PSS. Over 1440 h (60 days) of the stability test, an organic solar cell (OSC) with NP-V2O5 showed a significant durability, maintaining 82% of its initial power conversion efficiency (PCE), whereas an OSC with PEDOT:PSS maintained 51% of its initial PCE. Furthermore, due to the positive effects of the modified surface properties of NP-V2O5, the PCE was slightly enhanced from 7.47% to 7.89% with a significant improvement in the short-circuit current density and fill factor.

A high-performance biomaterial-based resistive switching (RS) device is fabricated by harnessing a thermally denatured protein (hexa-His-tagged recombinant molecular chaperone DnaJ (rDnaJ)) as a switching layer in a Cu/rDnaJ/Pt configuration on SiO2/Si substrate. The conductivity of the heat-denatured rDnaJ protein layer between the metal electrodes can be reversibly controlled to enable the formation/rupture of conductive Cu filaments by tailoring the metal chelating properties of the amino acid residues in the insulating protein matrix in a pH- and/or redox potential-dependent manner, giving rise to high-performance nonvolatile RS behavior. The rDnaJ-based RS device exhibits extremely low set voltage (∼0.12 V) and reset voltage (∼−0.08 V) with excellent uniformity, along with large memory window (RHRS/RLRS > 106) and long retention time (>106 s). In addition, the rDnaJ RS device, which is fabricated on a flexible poly(ethylene terephthalate) substrate, exhibits an uncompromised switching performance. Th...

The use of biomolecules as templates for biomineralization is widely viewed as a favorable green synthesis route to produce particles of tailored properties. To synthesize TiO2 particles suitable for lithium ion battery (LIB) anodes, four different types of biotemplates (i.e., native and denatured lysozyme with or without phosphate) were used to direct TiO2 biomineralization. The different size, morphology, and rigidity of the deliberately designed biotemplates enabled the controlled mineralization of TiO2 particles of versatile morphology, particle/grain/pore size, crystallinity, surface area, and specific pore volume. This rendered differential electrochemical characteristics and potential of the biomineralized TiO2 as LIB anode. In particular, meso-macroporous hollow spherical TiO2 (biomineralized using denatured lysozyme in the presence of phosphate ions, followed by calcination at 500 °C) shows great potential to be used as an LIB anode for high-power application with its average specific capacity of...

Because disinfectants have been essential during the COVID-19 pandemic, the global demand for benzalkonium chlorides (BACs) has significantly increased. BACs can inactivate coronaviruses, but are known as toxic. In this study, we investigated the adsorption mechanisms of BAC12, BAC14, and BAC16 in water using powdered activated carbon (PAC). The effects of the reaction time, pH, and temperature on the adsorption kinetics of BACs were examined. The adsorption reaction followed pseudo-second-order kinetics, and better fitted to the Langmuir isotherm than the Freundlich isotherm. The best adsorption of BACs was achieved at neutral pH conditions. Thermodynamic analysis revealed that adsorption of BACs onto PAC is a spontaneous and endothermic process. Competitive adsorption experiments revealed that BACs with longer alkyl chains were adsorbed more effectively onto PAC than shorter alkyl chain BACs, implying that, while the electrostatic interaction is an important adsorption mechanism for BAC12, van der Waals interaction plays a more important role during the adsorption of BAC14 and BAC16. Finally, we observed the partial detoxification (69%) BAC in adsorption treated water with PAC using a Microtox test.

Copyright: © 2021 by the authors. Diverse drug loading approaches for human heavy-chain ferritin (HFn), a promising drug nanocarrier, have been established. However, anti-tumor drug loading ratio and protein carrier recovery yield are bottlenecks for future clinical application. Mechanisms behind drug loading have not been elaborated. In this work, a thermally induced drug loading approach was introduced to load anti-tumor drug doxorubicin hydrochloride (DOX) into HFn, and 2 functionalized HFns, HFn-PAS-RGDK, and HFn-PAS. Optimal conditions were obtained through orthogonal tests. All 3 HFn-based proteins achieved high protein recovery yield and drug loading ratio. Size exclusion chromatography (SEC) and transmission electron microscopy (TEM) results showed the majority of DOX loaded protein (protein/DOX) remained its nanocage conformation. Computational analysis, molecular docking followed by molecular dynamic (MD) simulation, revealed mechanisms of DOX loading and formation of by-product by investigating non-covalent interactions between DOX with HFn subunit and possible binding modes of DOX and HFn after drug loading. In in vitro tests, DOX in protein/DOX entered tumor cell nucleus and inhibited tumor cell growth. joint Ph.D. Scholarship Scheme of the University of Adelaide and Institute of Process Engineering, Chinese Academy of Sciences, the National Natural Science Foundation of China [Grant No. 21576267]; Beijing Natural Science Foundation [Grant Number 2162041].

Highly accurate and prompt monitoring of cortisol is imperative for the prevention of stress-related diseases. In this study, we present a novel electrochemical biosensor for cortisol detection harnessing an electrochemical sensing platform consisting of a reduced graphene oxide (rGO) electrode, a bifunctional protein interlayer, and an antibody probe that specifically recognizes cortisol molecules. A thermally denatured bovine serum albumin (d-BSA) protein layer was directly adsorbed as an interlayer onto the rGO electrode surface via pi-stacking interactions, which provides the bifunctionality of creating covalent anchoring sites for anti-cortisol antibody probes and preventing the nonspecific binding of undefined substances. Electrochemical impedance spectroscopic (EIS) measurements show that the constructed sensing platform (antibody/d-BSA/rGO) exhibits picomolar-range sensitivity cortisol detection with a wide linear dynamic range spanning 10 pM–100 nM. In addition, our sensor exhibits high selectivity toward cortisol with negligible cross-binding reactivity to the cortisol analogs, aldosterone and progesterone. Moreover, almost complete spike recovery was confirmed with cortisol present in human saliva samples containing several interfering compounds. The demonstrated strategy for constructing the protein/rGO composite sensing platform is simple but versatile. Therefore, it is expected to facilitate efficient interfacing of various biomolecular probes with graphene-based and/or other electrode materials with hydrophobic surfaces.

A novel biosensor harnessing a peptide layer which has specific affinity to lead ion proved to be highly effective for electrochemical analysis of lead ions. The peptide modified electrode was used for the electrochemical analysis of various trace metal ions by square wave voltammetry. Compared to the other ions investigated, the peptide modified electrode was found to be highly selective to Pb2+ in the range of 50–700 nM. Furthermore, the biosensor exhibited a high reusability and good spike recovery in the tap water containing various concentration of Pb2+.

Caproic acid (CA) was produced by Megasphaera elsdenii T81 with Jerusalem artichoke tubers (JA) as a feedstock. More CA was produced under the medium with the acid hydrolysate of JA than the comparative medium with a carbon composition similar to that of JA. CA was produced up to 13.0 g/L and 0.52 g/L/h with extractive fermentation using a mixed solvent of alamine 336 in oleyl alcohol at 37 °C. The JA cost to produce 1 ton of CA is only 505 USD, which is much lower than that required for purchasing sucrose (860 USD) in CA production. As a result of the analysis performed using SuperPro Designer, including the cost of distillation to obtain pure CA, the estimated production cost for CA from dry JA is 1869 USD/ton CA at the production scale of 2000 ton/year, which is lower than the current market price for petroleum-derived CA (~2500 USD/ton).

In order to improve the sensitivity of electrochemical impedance spectroscopy (EIS)-based biosensors, a number of structuring strategies to promote enlarging the electroactive surface area have been recently proposed. However, these approaches have not been applicable to graphene-based electrodes especially due to their ultrathin film thickness (usually

UNLABELLED Transition metal oxide (TMO) thin films have been exploited as interlayers for charge extraction between electrodes and active layers in organic photovoltaic (OPV) devices. Additionally, graphene-electrode-based OPVs have received considerable attention as a means to enhance device stability. However, the film deposition process of a TMO thin-film layer onto the graphene electrode is highly restricted owing to the hydrophobic nature of the graphene surface; thus, the preparation of the device should rely on a vacuum process that is incompatible with solution processing. In this study, we present a novel means for creating a thin tungsten oxide (WO3 ) interlayer on a graphene electrode by employing an engineered biotemplate of M13 viruses, whereby nondestructive functionalization of the graphene and uniform synthesis of a WO3 thin interlayer are concurrently achieved. As a result, the incorporated virus-templated WO3 interlayer exhibited solar-conversion efficiency that was 20 % higher than that of conventional OPVs based on the use of a (3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PEDOT PSS) interlayer. Notably, bilayer-structured OPVs with synergistically integrated WO3 /PEDOT:PSS achieved >60 % enhancement in device performance.

Peptide-displaying Escherichia coli cells were investigated for use in adsorptive removal of bisphenol A (BPA) both in Luria-Bertani medium including BPA or ATM thermal paper eluted wastewater. Two recombinant strains were constructed with monomeric and dimeric repeats of the 7-mer BPA-binding peptide (KSLENSY), respectively. Greater than threefold increased adsorption of BPA [230.4 µmol BPA per g dry cell weight (DCW)] was found in dimeric peptide-displaying cells compared to monomeric strains (63.4 µmol per g DCW) in 15 ppm BPA solution. The selective removal of BPA from a mixture of BPA analogs (bisphenol F and bisphenol S) was verified in both monomeric and dimeric peptide-displaying cells. The binding chemistry of BPA with the peptide was assumed, based on molecular docking analysis, to be the interaction of BPA with serine and asparagine residues within the 7-mer peptide sequence. The peptide-displaying cells also functioned efficiently in thermal paper eluted wastewater containing 14.5 ppm BPA.

Titanium-tungsten oxide composites with greatly enhanced photocatalytic activity were synthesized by lysozyme-mediated biomineralization. It was shown for the first time that simple control of the onset of biomineralization could enable fine tuning of the composition and crystallinity of the composites to determine their photocatalytic performance.

The O specific polysaccharide (OSP) of the lipopolysaccharide (LPS) of Salmonella enterica serovar Paratyphi A is a protective antigen and the target for vaccine development. LPS is the major constituent of the outer membrane of S. Paratyphi A with the OSP exposed on the surface, in addition to the cell associated LPS a large amount of free LPS was present in the fermentation broth. A purification method was developed to take advantage of both sources of LPS and to maximize recovery of OSP. After fermentation the bacterial cells were concentrated and washed, the permeate containing the free LPS was processed separately from the cells. The free LPS was concentrated and washed on a 100kD ultrafiltration membrane to remove low molecular weight impurities. The LPS was then detoxified by separation of the lipid A from the OSP using acid hydrolysis at 100°C, the precipitated lipid A was removed by 0.2μm membrane filtration. Contaminants were then removed by acid precipitation in the presence of sodium deoxycholate. The OSP was concentrated and washed with 1M NaCl then water using a 10kD ultrafiltration membrane then sterile filtered through a 0.2μm membrane filter. The cells were treated by acid hydrolysis at 100°C, the remaining cells, cell debris and precipitate was removed by centrifugation. The filtrate was then treated in the same way as described above for the free LPS. The combined yield of purified OSP from free LPS plus the cells was greater than 880mg/L of culture broth. The method developed yields large amounts of OSP, is scalable and compatible with cGMP so would be readily transferrable to developing country vaccine manufacturers for low cost production of vaccine against S. Paratyphi A.

Biomimetic environmental benign synthesis of electrocatalysts with inexpensive transition metal compounds is a promising approach to achieve clean hydrogen production with high sustainability via water splitting. Herein, a mussel-inspired facile synthesis of N-carbon encapsulated molybdenum carbide-phosphide (Mo2C–MoP) hybrid nanodots using a polydopamine biopolymer for efficient hydrogen evolution reactions (HERs), and long-term durability is demonstrated. The unique properties of polydopamine facilitate the transition metal ions (i.e., molybdenum) chelation without the use of additional toxic chelating agents. In the presence of phosphate buffer solution, the anchoring properties of polydopamine induce the formation of molybdenum-based complexes with the carbon and phosphide species, resulting in the synthesis of Mo2C–MoP hybrid nanodots encapsulated in nitrogen-doped carbon shell. Consequently, the Mo2C–MoP hybrid nanodots exhibit considerable electrocatalytic HER performance and long-term stability. The low overpotential of 147 mV is obtained at the high current density of 20 mA cm−2 along with the low Tafel value of 64.92 mV dec−1 in alkaline medium. Furthermore, the long-term stability over 120 h is achieved using Mo2C–MoP@CP. Therefore, the use of an environment-friendly biopolymer for the fabrication of noble-metal-free, efficient, and stable HER electrocatalysts can be a promising strategy to achieve sustainable and clean H2 production.

Vi capsular polysaccharide is the major component of Vi polysaccharide typhoid vaccines. Vi is synthesized during growth of Salmonella enterica subspecies enterica serovar Typhi and is released into the fermentation broth in large quantities. Along with the Vi considerable amounts of impurities consisting of bacterial protein, nucleic acid and lipopolysaccharide (LPS) as well as media components contaminate the fermentation broth. A purification method based on selective precipitation of Vi using the cationic detergent cetavlon was developed to separate impurities from Vi. A novel method for handling the Vi precipitate using 0.2 μm sterilizing grade filters to trap and wash the Vi and then, after re-solubilization, allow the Vi to pass through the filter was developed. Cetavlon selectively precipitates Vi and is the major purification step in the process, however, the conditions must be carefully controlled otherwise LPS will co-precipitate in large quantities. Various diafiltration steps help to remove contaminating protein, nucleic acid and fermentation media components as well as chemicals added during the process to induce precipitation of either Vi or contaminants. The final yield of purified Vi was approximately 45% and the bulk concentrate complied with the specifications defined in the WHO recommendations for Vi polysaccharide vaccine. Analysis of the Vi by size exclusion chromatography revealed a uniform peak with a narrow size distribution. The Nuclear Magnetic Resonance spectrum was similar to Vi produced by other methods. The method developed produces large quantities of Vi using low cost production methods translating into Vi based vaccines that can be produced at affordable prices for use in developing countries.

Lead ion is one of the most hazardous and ubiquitous heavy metal pollutants and poses an increasing threat to the environment and human health. This necessitates rapid and selective detection and/or removal of lead ions from various soil and water resources. Recently, we identified several Pb 2+ binding peptides via phage display technique coupled with chromatographic biopanning ( Nian et al., 2010 ) where a heptapeptide (TNTLSNN) capable of recognizing Pb 2+ with high affinity and specificity evolved. In the present study, an electrochemical sensor harnessing this Pb 2+ affinity peptide as a probe on a porous gold electrode was developed. The three dimensional porous gold electrode was obtained from electrochemical deposition using the dynamic hydrogen bubble template method. A thin layer of poly(thiophene acetic acid) (PTAA) was coated on the porous gold surface. The Pb 2+ recognizing peptide was immobilized via amide linkage on the PTAA. The developed biosensor was demonstrated to be fast, selective and reproducible in Pb 2+ detection, exhibiting Pb 2+ -specific peak current values around −0.15 V in a broad concentration range (1−1×10 7 nM) in 10 min despite the repeated use after regeneration.

In the present study, a novel impedance aptasensor was developed by immobilizing HER2 (human epidermal growth factor receptor 2)-specific single stranded DNA aptamer onto the monolayer of 3-mercaptopropionic acid self-assembled on gold nanoparticles electrode. The efficiency of each electrode modification step and the performance of thus constructed aptasenor were assessed by impedance spectroscopy. The impedance response of the aptasensor showed a proportional relationship with the concentrations of HER2 ranged from 10 −5 to 10 2 ng/mL. The aptasensor showed fast HER2 detection with negligible cross reactivity to various compounds likely to exist in human serum samples (e.g. glucose, IgG, DNA and RNA), indicative of excellent sensitivity and specificity of the aptasensor. The aptasensor could be regenerated by a simple pH-shift method. Considering these advantages of the developed aptasensor, it could provide a good potential sensing platform for non-invasive early detection of breast cancer biomarkers.

Bisphenol A (BPA) is a highly hazardous component to human since it is regarded as one of endocrine disruptors. For the analysis and/or removal of BPA, the searching for the specific ligand with a selective affinity to target BPA is required. In order to find the peptide moiety that specifically binds to BPA, the ultrasound-assisted biopanning was carried out with a phage-displayed peptide library expressing constrained heptamer. After six rounds of positive screening against BPA particles followed by the negative screening against the surface of eppendorf tube, the peptide sequence (CysLysSerLeuGluAsnSerTyrCys) with affinity to BPA was screened based on the order of frequency from the screened phage clones. To further verify the specificity of screened peptide sequence, the cross-binding affinity of the phage peptide toward BPA analogues such as Bisphenol S (BPS) and Bisphenol F (BPF) was also assessed, where the selected phage peptide showed a higher affinity to BPA over BPS and BPF.

For the selection of peptide specifically binding to Pb2+, the biopanning with the commercially available Ph.D.-7 phage displayed heptapeptide library was carried out against Pb2+ immobilized on a metal-chelating IDA (iminodiacetic acid) resin. After four rounds of screening against Pb 2+ -IDA including negative selections against charged bead with metal ions other than Pb2+ and uncharged bead, several candidate leadbinding phage peptides were initially determined based on the order of frequency from the screened phage clones. Of the selected phage peptide sequences, the peptide of the highest frequency, CysSerIleArgThrLeuHisGlnCys (CSIRTLHQC) also exhibited the strongest affinity for Pb 2+ in binding assays for individual phage clones. However, there was not a significant difference in Pb2+ affinity between selected peptides when using synthetic heptapeptides corresponding to the displayed peptide sequences of phage clones.

Neatly arranged gold nanoparticles (AuNPs) were directly electrodeposited on an electrochemically polymerized self-assembled monolayer (SAM) of thiol-functionalized 3,4-ethylenedioxythiophene (EDOT) derivative, EDTMSHA. A thiolated single-stranded DNA (ssDNA) aptamer with high specificity to LPS was immobilized on the AuNPs/conducting polymer composite film, serving as sensing platform for LPS detection. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscope (SEM), and atomic force microscopy (AFM) were utilized to characterize the modification and detection processes. The electron transfer resistance was found to have a linear relationship with LPS concentration from 0.1 pg/mL to 1 ng/mL.

A highly specific lead-binding peptide ThrAsnThrLeuSerAsnAsn was displayed on Escherichia coli, and lead adsorption characteristics of the recombinant bacteria were investigated. Cell surface-displayed peptide was expressed under the control of an arabinose promoter using outer membrane protein C (OmpC(t)) as an anchoring motif. The optimal induction period and arabinose concentration for the expression of peptide-fused OmpC(t) were determined to be 2 h and 0.001 g/L, respectively. Selective adsorption of Pb(2+) onto recombinant cells was verified with individual or combinatory use of four metal ions, Pb(2+), Ni(2+), Co(2+), and Cu(2+); the amount of bound Pb(2+) onto the biosorbents was significantly higher than the other metal ions. The adsorption isotherm of recombinant cells for Pb(2+) followed the Langmuir isotherm with a maximum adsorption loading (q (max)) of 526 μmol/g dry cell weight.

A facile method for detection of lipopolysaccharide (LPS) on metal complex immobilized gold electrode is described. The metal complex modified electrode was constructed from a gold electrode modified with Cu and nitrilotriacetic acid (NTA) complex, which binds to the O-side chain of LPS in gram-negative cells. The electrochemical impedance spectroscopy (EIS) was used to detect interaction of LPS with NTA–Cu complex. The performance of the NTA–Cu sensor was investigated by EIS and a linear relationship was observed between charge transfer resistance ( R et ) and LPS concentration in the range of 0.0001–0.1 ng mL −1 . The NTA–Cu complex exhibited insignificant binding to DNA, RNA, bovine serum albumin, glucose, and cholesterol whereas LPS interacted strongly in the biological species. Furthermore, the NTA–Cu sensor was easily regenerated from EDTA solution, and the regenerated sensor demonstrated response sensitivities similar to the original sensor with a deviation of only 4%. These findings show that the NTA–Cu modified gold electrode can be used to detect LPS in real-time.

Lipopolysaccharide (LPS), also known as endotoxin, triggers a fatal septic shock; therefore, fast and accurate detection of LPS from a complex milieu is of primary importance. Several LPS affinity binders have been reported so far but few of them have proved their efficacy in developing electrochemical sensors capable of selectively detecting LPS from crude biological liquors. In this study, we identified 10 different single-stranded DNA aptamers showing specific affinity to LPS with dissociation constants ( K d ) in the nanomolar range using a NECEEM-based non-SELEX method. Based on the sequence and secondary structure analysis of the LPS binding aptamers, an aptamer exhibiting the highest affinity to LPS (i.e., B2) was selected to construct an impedance biosensor on a gold surface. The developed electrochemical aptasensor showed excellent sensitivity and specificity in the linear detection range from 0.01 to 1 ng/mL of LPS with significantly reduced detection time compared with the traditional Limulus amoebocyte lysate (LAL) assay.

Targeted drug delivery is especially important in cancer treatment as many anti-cancer drugs are non-specific and highly toxic to both cancer and normal cells. The targeted drug delivery of DOX to the MUC1-expressing breast cancer cell line (MCF7) was obtained using APT as a carrier. Modification of the APT-DOX complex by PEG increases the survivability of the macrophage control (RAW 264.7) by about six-fold as compared to free DOX treatment without significantly affecting the cytotoxicity toward the target cell line. Thus, PEG-APT-DOX is potentially a new therapeutic agent for targeted drug delivery to MUC1-expressing cell lines.

A novel means of generating highly interconnected and nano-channeled photoelectrodes by employing one-dimensionally shaped M13 viruses as a sacrificial template is proposed for highly efficient dye-sensitized solar cells (DSSCs). The electrostatic binding between oppositely charged TiO2 nanoparticles and M13 viruses provides a uniform complexation and suppresses random aggregation of TiO2 nanoparticles. After the calcination process, the traces of viruses leave porously interconnected channel structures inside TiO2 nanoparticles, providing efficient paths for electrolyte contact as well as increased surface sites for dye adsorption. As a result, DSSCs generated using a sacrificial virus template exhibit an enhanced current density (JSC) of 12.35 mA cm-2 and a high photoconversion efficiency (η) of 6.32%, greater than those of conventional photoelectrodes made of TiO2 nanoparticles (JSC of 8.91 mA cm-2 and η of 4.67%). In addition, the stiffness and shape of the M13 virus can be varied, emphasizing the usefulness of the one-dimensional structural characteristics of M13 viruses for the highly interconnected porous structure of DSSC photoelectrodes.

Biodegradable amphiphilic copolymers were successfully synthesized by the conjugation of various densities of hydrophobic biocompatible cholesterol (Chol) moieties onto poly(2-hydroxyethyl aspartamide) and poly(N-isopropylaminoethyl-co-2-hydroxyethyl aspartamide). These were obtained from polysuccinimde, the thermal polycondensation product of L-aspartic acid, via a ring-opening reaction with multifunctional pendant groups, including ethanolamine and N-isopropylethylenediamine (NIPEDA). Copolymers containing 5-30 mol % Chol showed self-aggregation behavior in aqueous solution, as evidenced by the dynamic light scattering measurement of their particle size distribution. The average particle size of these copolymers increased linearly with increasing Chol content. Moreover, the presence of secondary amine groups in the poly(2-hydroxyethyl aspartamide)-NIPEDA system made the conjugation more efficient; however, these also seemed to accelerate the degradation of the copolymers in an aqueous medium. The degradation behavior and pH dependence of the particle size of these copolymers in aqueous solution were also examined.

Toxic heavy metal pollution is a global problem occurring in air, soil as well as water. There is a need for a more cost effective, renewable remediation technique, but most importantly, for a recovery method that is selective for one specific metal of concern. Phage display technology has been used as a powerful tool in the discovery of peptides capable of exhibiting specific affinity to various metals or metal ions. However, traditional phage display is mainly conducted in batch mode, resulting in only one equilibrium state hence low-efficiency selection. It is also unable to monitor the selection process in real time mode. In this study, phage display technique was incorporated with chromatography procedure with the use of a monolithic column, facilitating multiple phage-binding equilibrium states and online monitoring of the selection process in search of affinity peptides to Pb2+. In total, 17 candidate peptides were found and their specificity toward Pb2+ was further investigated with bead-based enzyme immunoassay (EIA). A highly specific Pb2+ binding peptide ThrAsnThrLeuSerAsnAsn (TNTLSNN) was obtained. Based on our knowledge, this is the first report on a new chromatographic biopanning method coupled with monolithic column for the selection of metal ion specific binding peptides. It is expected that this monolith-based chromatographic biopanning will provide a promising approach for a high throughput screening of affinity peptides cognitive of a wide range of target species.

Novel derivatives of poly(aspartic acid) conjugated with various amino acids and their amphiphilic copolymers were synthesized and characterized. Methyl esters of various amino acids (in their hydrochloride form) were synthesized from the reaction of amino acids with methanol in the presence of chlorotrimethylsilane (TMSCl). Aminolysis reaction onto polysuccinimide (PSI) using various amino acid methyl esters in the presence of catalyst and the followed hydrolysis provided the corresponding amino acid-conjugated poly(aspartic acid) derivatives in high reaction yield. Amino acid—conjugated amphiphilic analogs were also prepared by introducing hydrophobic alkylamine along with amino acid using a similar procedure. The chemical structures of copolymers were confirmed by FT-IR and 1H NMR spectroscopy. The physicochemical properties of amphiphilic copolymers were characterized using dynamic light scattering (DLS), fluorescence spectroscopy and field emission scanning electron microscopy (FE-SEM). In addition, the in vitro cell viability of the copolymers was examined. These polymers have potential applications in the pharmaceutical and cosmetic fields as delivery vehicles for bioactive molecules.

This paper studies the detection of copper ions by using an iminodiacetatic acid (IDA) modified conducting copolymer electrode. The copolymer film comprising 3-methyl thiophene (3MT) and 3-thiophene acetic acid (3TA) was chosen as the selective metal cation sensing electrode. The carboxylic group of the copolymer was modified to produce IDA group for metal ion capture. The modified electrode was used for the electrochemical analysis of trace copper ions by square wave voltammetry (SWV) technique. The electrode was found to be highly selective to Cu 2+ in the range of 0.1–10 μM. The modified electrode offered an excellent way, with a high stability and reusability, for selective determination of Cu 2+ in a solution of mixed metal ions.

The potential of utilizing the DNA binding protein lac repressor (LacI) to organize inorganic nanoparticles (NPs) is explored in this study. A peptide cognitive of both SiO2 and TiO2 simultaneously (STB1, -CHKKPSKSC-) is genetically engineered into the C-terminus of LacI to give LacI-STB1, and the inserted STB1 peptides in the context of LacI-STB1 molecules are shown to actively interact with both SiO2 and TiO2. Wild-type LacI is found to interact with the two surfaces at its flexible N-terminal DNA binding domain, and LacI-STB1 exhibits much stronger binding affinity to both surfaces by harnessing a second binding region (STB1 peptide) fused at its C-terminus. The quantitative analysis of binding kinetics reveals that, compared to wild-type LacI with one binding region (N-terminus), two remote binding regions (N-terminus and C-terminus) in LacI-STB1 do not lead to faster adsorption rates to the two surfaces, but remarkably slow down the desorption rates. Finally, using LacI-STB1 as a linker, the successful assembly of a sandwich nanostructure of DNA/LacI-STB1/TiO2 NPs is demonstrated using surface plasmon resonance (SPR) measurements and TEM. The demonstrated LacI-STB1-mediated assembly of TiO2 NPs on DNA scaffold may provide a generic platform for controlled spatial arrangement of various nanoparticles of engineering interest.

Gloshedobin, a recently isolated thrombin-like enzyme from the snake venom of Gloydius shedaoensis, is expressed mainly in the form of inclusion bodies (IBs) in Escherichia coli due to its cysteine-rich nature. Following extraction and solubilization of the IBs, one-step immobilized metal affinity chromatography purification produces highly purified (>99%) denatured-solubilized gloshedobin ready to enter the subsequent refolding process. However, the traditional dilution or column refolding strategy, based on gradual denaturant removal, is found to be inefficient for the recovery of protein activity. In this study, a new refolding strategy harnessing the ClpB and DnaK/DnaJ/GrpE bichaperone system is demonstrated to be superior to the conventional refolding methods in either batch dilution or column refolding mode. It is noted that the efficacy of bichaperone-mediated column refolding strategy is further highlighted especially when refolding reaction is attempted at a higher protein concentration with the recirculation of the refolding cocktail containing the bichaperone system. This is evidenced by an uncompromised refolding efficiency (ca. 21.4%) achieved at 2000 microg/mL of initial protein concentration, which is comparable to the refolding efficiency (ca. 22.5%) obtained at 20 times lower protein concentration (i.e. 100 microg/mL) in the conventional batch dilution refolding technique. The demonstrated chaperone-assisted column refolding strategy thus provides an effective tool for refolding-recalcitrant proteins whose reactivation is otherwise difficult to achieve.

Snake venom thrombin-like enzymes (TLEs) have been widely studied for potential therapeutic applications as anti-coagulants in the treatment of blood clotting disorders. However, due to the cysteine-rich nature of these proteins, their expressions in Escherichia coli were often impeded by inclusion body (IB) formation. The formation of truncated expression products significantly complicated the production of gloshedobin, a recently isolated TLE from the snake venom of Gloydius shedaoensis [Yang, Q., Li, M., Xu, J.Q., Bao, Y.M., Lei, X.Y., An, L.J., 2003a. Expression of gloshedobin, a thrombin-like enzyme from the venom of Gloydius shedaoensis , in Escherichia coli . Biotechnology Letters 25, 101–104; Yang, Q., Xu, J.Q., Li, M., Lei, X.Y., An, L.J., 2003b. High-level expression of a soluble snake venom enzyme, gloshedobin, in E. coli in the presence of metal ions. Biotechnology Letters 25, 607–610]. In this work, it was found that the expression of gloshedobin was strongly dependent on the expression host. The truncated expression was reduced by 25% when the protein was expressed in E. coli BL21(DE3)pLysS instead of BL21(DE3). It was also demonstrated that co-expression of ClpB (a molecular chaperone) in BL21(DE3) enabled the expression of gloshedobin mostly in intact form without compromising expression level, while almost completely eliminating its truncation products. This suggests a new simple strategy to significantly improve the quality of protein expression in TLE production and may find its useful application for many other recombinant proteins whose expressions and/or purifications are hindered by the formation of truncation products.

The Escherichia coli heat-shock protein ClpB can efficiently solubilize protein aggregates and refold them into active proteins in cooperation with the DnaK–DnaJ–GrpE chaperone (DnaKJE) system. However, the application of this bichaperone system at a large-scale was restricted because of the difficulties and high cost to express and purify each of these molecular chaperones. In this study, we constructed a plasmid encoding ClpB with a 6xHis-tag at its C-terminus (His-ClpB) to facilitate its purification through Immobilized Metal Affinity Chromatography (IMAC). A different plasmid capable of expressing the DnaKJE was used to obtain a cell extract containing unpurified DnaKJE. The effect of purified His-ClpB and unpurified DnaKJE on the refolding of heat-denatured malate dehydrogenase (MDH) was investigated, and proved to be highly efficient for MDH refolding. Furthermore, the use of both unpurified His-ClpB and DnaKJE available in the cell extract enabled highly successful refolding of the heat-denatured MDH with efficacy comparable to the case where the purified His-ClpB was used. To the best of our knowledge, this is the first attempt to apply a refolding cocktail comprising unpurified bichaperone system to the refolding of a heat-denatured protein, providing a practical and economically viable way of implementing a large-scale folding-like-refolding strategy.