Buffer Type Research Articles

Iterated Local Search and Other Algorithms for Buffered Two-Machine Permutation Flow Shops with Constant Processing Times on One Machine.

The two-machine permutation flow shop scheduling problem with buffer is studied for the special case that all processing times on one of the two machines are equal to a constant c. This case is interesting because it occurs in various applications, for example, when one machine is a packing machine or when materials have to be transported. Different types of buffers and buffer usage are considered. It is shown that all considered buffer flow shop problems remain NP-hard for the makespan criterion even with the restriction to equal processing times on one machine. However, the special case where the constant c is larger or smaller than all processing times on the other machine is shown to be polynomially solvable by presenting an algorithm (2BF-OPT) that calculates optimal schedules in O(nlogn) steps. Two heuristics for solving the NP-hard flow shop problems are proposed: (i) a modification of the commonly used NEH heuristic (mNEH) and (ii) an Iterated Local Search heuristic (2BF-ILS) that uses the mNEH heuristic for computing its initial solution. It is shown experimentally that the proposed 2BF-ILS heuristic obtains better results than two state-of-the-art algorithms for buffered flow shop problems from the literature and an Ant Colony Optimization algorithm. In addition, it is shown experimentally that 2BF-ILS obtains the same solution quality as the standard NEH heuristic, however, with a smaller number of function evaluations.

Using alternative buffer for DNA genomic isolation in forest trees

DNA optimization procedures can be carried out on the type of buffer used during extraction or physical handling techniques in separating genomic DNA from other compounds. The research using Three types of buffer: 1. CTAB, 2. Detergents containing Alkyl Benzene Sulfonate (ABS) surfactants and Three Detergents containing Sodium Laureth Sulphate (SLS) surfactants. This study aims to obtain an optimal DNA isolation method to produce genomic DNA of good quality and sufficient quantity so that it can be used for genetic diversity analysis in forest trees and to determine the optimal alternative buffer for CTAB to facilitate DNA isolation in remote areas, which generally hard to get CTAB. The parameters measured in this study were the presence of DNA and DNA concentration. The results showed that DNA isolation of 12 species of forest trees was successfully carried out using CTAB buffer and Detergent containing ABS surfactants by visualizing the genomic DNA bands from the results of the electrophoresis and Nanodrop spectrophotometer meanwhile Detergent containing SLS surfactants buffer was not successful in DNA isolation. The highest DNA quantity (DNA concentration) was found in 19 samples using CTAB buffer and the detergent containing ABS surfactants buffer with a concentration of 1403,8 - 3412,7 ng/µl. The conclusion of this study was CTAB buffer and the Detergent containing ABS surfactants can also be used as an alternative to a simple buffer for DNA isolation experiments.

The polyaminosaccharide-based buffers as a new type of zwitterionic buffering macromolecules for biochemical applications

A new type of biocompatible buffers based on zwitterionic polyaminosaccharides is reported. The carboxy- and amino-groups containing carboxymethyl chitosan (CM-CS) was synthesized and reacted with hydrochloric/acetic acid resulting in CM-CS-HCl and CM-CS-HAc buffers with buffering capacity of 20.6 and 15.2 mM/pH. The new buffers were comprehensively characterized for their physicochemical properties and checked on enzymatic reactions of acetylcholinesterase (AChE) and alkaline phosphatase (ALP). Their performance was compared to the phosphate and Tris buffers. The chloride-free, CM-CS-HAc demonstrated excellent buffering activity with Michaelis constants of 0.50 and 1.00 mM and maximum reaction rates of 5.62 and 2.26 μmol/min/mL for AChE and ALP reactions, respectively. Toxicity studies on stress-sensitive bioreporter bacteria verified nontoxicity of CM-CS-HAc.Zwitterionic polyaminosaccharides overcome drawbacks of monomeric buffers, such as interference with enzyme active sites, cell membrane injury and purification difficulties. Therefore, they may become the next generation of effective buffers for biological and biochemical applications.

TiO2 Simultaneous Enrichment, On-Line Deglycosylation, and Sequential Analysis of Glyco- and Phosphopeptides.

Reversible protein glycosylation and phosphorylation tightly modulate important cellular processes and are closely involved in pathological processes in a crosstalk dependent manner. Because of their significance and low abundances of glyco- and phosphopeptides, several strategies have been developed to simultaneously enrich and co-elute glyco- and phosphopeptides. However, the co-existence of deglycosylated peptides and phosphopeptides aggravates the mass spectrometry analysis. Herein we developed a novel strategy to analyze glyco- and phosphopeptides based on simultaneous enrichment with TiO2, on-line deglycosylation and collection of deglycosylated peptides, and subsequent elution of phosphopeptides. To optimize on-line deglycosylation conditions, the solution pH, buffer types and concentrations, and deglycosylation time were investigated. The application of this novel strategy to 100 μg mouse brain resulted in 355 glycopeptides and 1,975 phosphopeptides, which were 2.5 and 1.4 folds of those enriched with the reported method. This study will expand the application of TiO2 and may shed light on simultaneously monitoring protein multiple post-translational modifications.

Freeze-thaw stability of aluminum oxide nanoparticles

The use of inorganic nanoparticles (NPs) gains interest for pharmaceutical applications, e.g. as adjuvants or drug delivery vehicles. Colloidal stability of NPs in aqueous suspensions is a major development challenge. Both frozen and lyophilized liquids are alternative presentations to liquid dispersion. To improve the basic understanding, we investigated the freeze-thawing stability of model α-Al2O3 NPs. Freeze-thawing was conducted in three different buffer types at pH5 and 8 without and with additives to determine fundamental formulation principles. Before freeze-thawing, α-Al2O3 NPs could be stabilized in sodium citrate buffer at pH5 and 8, and in sodium or potassium phosphate at pH8. Particles revealed low zeta potential values in phosphate buffers at pH5 indicating insufficient electrostatic stabilization. After freeze-thawing, an increase in NP size was strongly reduced in potassium phosphate and sodium citrate buffers. Subsequent pH measurements upon freezing revealed a drastic acidic pH shift in sodium phosphate which was further demonstrated to destabilize NPs. The ionic stabilizers gelatin A/B, Na-CMC, and SDS, were suitable to improve colloidal stability in phosphate buffers at pH5 highlighting the importance of charge stabilization. Freeze-thawing stability was best in presence of gelatin A/B, followed by PVA, mannitol, or sucrose. Depletion and steric stabilization were insufficient using PEG and surfactants respectively. Thus, we could identify the fundamental formulation principles to preserve inorganic NPs upon freezing: i) sufficient charge stabilization, ii) a maintained pH during freezing, and iii) the addition of a suitable stabilizer, preferably gelatin, not necessarily surfactants. This forms the basis for future studies, e.g. on lyophilization.

Formulation, process, and storage strategies for lyophilizates of lipophilic nanoparticulate systems established based on the two models paliperidone palmitate and solid lipid nanoparticles

Lyophilization formulation and process development for lipophilic nanoparticle (NPs) products is highly challenging as the NPs have a low colloidal stability. We compared two different NP types, pure paliperidone palmitate nanocrystals and trimyristin solid lipid nanoparticles regarding formulation, process, and storage stability aspects. Freeze-thaw studies were conducted to investigate the basic formulation aspects such as buffer type, pH, and ionic strength as well as different cryoprotectants. In freeze-drying conventional ramp freezing was performed and compared to freezing with an annealing step added or with controlled ice nucleation. Different formulations were lyophilized and tested for short-term storage stability up to 6 weeks. Samples were analyzed for particle size, subvisible particle number, specific surface area, residual moisture, crystallinity, and glass transition temperature. Sucrose significantly better stabilized both NP types against freeze-thaw stress compared to mannitol demonstrating the importance of a fully amorphous matrix. While the impact of buffer type and pH was negligible, the aggregation propensity of NPs was reduced in presence of NaCl. The freezing step also impacted NP aggregation but the effect was less important than the formulation design. Surfactants did not necessarily improve the colloidal stability but resulted in a lower glass transition temperature of the lyophilizates and may cause phase separation which limits storage stability. This hurdle can be overcome by using a hydroxypropyl–β–cyclodextrin/ sucrose mixture as cryoprotectant. In general, we could show a similar freeze–drying behavior of the two NP types. Thus, we established a formulation and process approach to achieve stable lyophilizates of lipophilic NPs based on two different types of NPs. The general rules should be transferable to other NPs facilitating lyophilization development.

Experimental and computational study on the enantioseparation of four chiral fluoroquinolones by capillary electrophoresis with sulfated-β-cyclodextrin as chiral selector.

In this work, enantioseparation of four chiral fluoroquinolones (FQs), namely, ofloxacin, gemifloxacin, lomefloxacin, and gatifloxacin, was achieved by capillary electrophoresis with sulfated-β-cyclodextrin (S-β-CD) as chiral selector. Factors affecting the enantiomeric resolution, such as the concentrations of S-β-CD, BGE pH conditions, and the buffer types and concentrations, were optimized and discussed. A BGE consisting of 30 g/L S-β-CD and 30-mM phosphate at pH4.0 was found fit for enantiomeric resolution of ofloxacin and gemifloxacin, while the same BGE at pH3.0 was suitable for enantioseparation of lomefloxacin and gatifloxacin. The pH-dependent experiments showed that separation resolutions of four FQs enantiomers were significantly affected by BGE pH, which was thought to be related with the varying electrostatic attraction between the enantiomers and chiral selector. To verify this speculation, molecular docking studies were used for further investigation of the enantiomeric recognition mechanism of S-β-CD. Molecular model indicated that hydrophobic effect and hydrogen bond were involved in host-guest inclusion, but the electrostatic attraction enhanced the chiral discrimination by increasing the difference in binding energy between individual enantiomers and S-β-CD. This work provided a further insight into the chiral recognition mechanisms of CD derivatives.

Root Functional Trait and Soil Microbial Coordination: Implications for Soil Respiration in Riparian Agroecosystems.

Predicting respiration from roots and soil microbes is important in agricultural landscapes where net flux of carbon from the soil to the atmosphere is of large concern. Yet, in riparian agroecosystems that buffer aquatic environments from agricultural fields, little is known on the differential contribution of CO2 sources nor the systematic patterns in root and microbial communities that relate to these emissions. We deployed a field-based root exclusion experiment to measure heterotrophic and autotrophic-rhizospheric respiration across riparian buffer types in an agricultural landscape in southern Ontario, Canada. We paired bi-weekly measurements of in-field CO2 flux with analysis of soil properties and fine root functional traits. We quantified soil microbial community structure using qPCR to estimate bacterial and fungal abundance and characterized microbial diversity using high-throughput sequencing. Mean daytime total soil respiration rates in the growing season were 186.1 ± 26.7, 188.7 ± 23.0, 278.6 ± 30.0, and 503.4 ± 31.3 mg CO2-C m–2 h–1 in remnant coniferous and mixed forest, and rehabilitated forest and grass buffers, respectively. Contributions of autotrophic-rhizospheric respiration to total soil CO2 fluxes ranged widely between 14 and 63% across the buffers. Covariation in root traits aligned roots of higher specific root length and nitrogen content with higher specific root respiration rates, while microbial abundance in rhizosphere soil coorindated with roots that were thicker in diameter and higher in carbon to nitrogen ratio. Variation in autotrophic-rhizospheric respiration on a soil area basis was explained by soil temperature, fine root length density, and covariation in root traits. Heterotrophic respiration was strongly explained by soil moisture, temperature, and soil carbon, while multiple factor analysis revealed a positive correlation with soil microbial diversity. This is a first in-field study to quantify root and soil respiration in relation to trade-offs in root trait expression and to determine interactions between root traits and soil microbial community structure to predict soil respiration.

Measurement of neighborhood-based physical activity bouts.

This study examined how buffer type (shape), size, and the allocation of activity bouts inside buffers that delineate the neighborhood spatially produce different estimates of neighborhood-based physical activity. A sample of 375 adults wore a global positioning system (GPS) data logger and accelerometer over 2 weeks under free-living conditions. Analytically, the amount of neighborhood physical activity measured objectively varies substantially, not only due to buffer shape and size, but by how GPS-based activity bouts are identified with respect to containment within neighborhood buffers. To move the "neighborhood-effects" literature forward, it is critical to delineate the spatial extent of the neighborhood, given how different ways of measuring GPS-based activity containment will result in different levels of physical activity across different buffer types and sizes.

Back Cover: Separation of pharmaceutically active compounds by multimodal chromatography with ultraviolet detection

The cover picture shows the retention behavior of positively charged thiamine and basic cytosine in mobile phases with three different buffer types at low and high acetonitrile (ACN) content on three different mixed-mode columns. All three columns contain the same C18 hydrophobic moiety and differ only in the hydrophilic parts (HILIC-1, WAX-1 and WCX-1). The effect of the buffer type on the retention is significantly affected by ACN content as well as the chemical structure of the analytes and columns. While differences in cytosine retention at low and high ACN content are comparable for all buffers tested, unexpectedly long retention is observed for thiamine at high ACN content, especially in combination with phosphate buffer.

A simple strategy for the detection of Pb(II) and Cu(II) by an electrochemical sensor based on Zn/Ni-ZIF-8/XC-72/Nafion hybrid materials

In this study, a novel electrochemical sensor for simultaneous detection of Pb(II) and Cu(II) was constructed by using Zn/Ni-ZIF-8/XC-72/Nafion hybrid material as electrode surface modifier. XRD, FT-IR, XPS and SEM were used to study the crystal structure, functional groups, element types and morphologies of the prepared materials. The electrochemical performance of the Zn/Ni-ZIF-8/XC-72/Nafion/GCE sensor were investigated by CV, EIS and DPV. In addition, the effects of various conditions including pH, the type of buffer and the ratio of Zn/Ni-ZIF-8 to XC-72 were also explored for the determination of Pb(II) and Cu(II). Under the optimum conditions, the constructed sensor exhibited outstanding linear response of Pb(II) (0.794–39.6 ppm) and Cu(II) (0.397–19.9 ppm) with detection limits of 0.0150 and 0.0096 ppm, respectively. Finally, the fabricated sensor was further used to detect Pb(II) and Cu(II) in real samples, and the satisfactory recovery was obtained.

Separation of labeled isomeric oligosaccharides by hydrophilic interaction liquid chromatography – the role of organic solvent in manipulating separation selectivity of the amide stationary phase

The advantages of using mixtures of organic solvents for the separation of labeled oligosaccharides on the amide stationary phase under hydrophilic interaction liquid chromatography conditions are presented. The effect of the type of buffer as well as solvent or their mixtures on retention of uracil, saccharide labeling reagents (2-aminobenzoic acid, 2-aminobenzamide, ethyl 4-aminobenzoate, procainamide), and corresponding labeled saccharides were evaluated. The successful isocratic separation of labeled isomeric trisaccharides (maltotriose, panose, and isomaltotriose) was achieved in the mobile phase consisting of a 90% (v/v) mixture of organic solvents (methanol/acetonitrile 60:40) and 10% (v/v) 30 mM ammonium formate, pH 3.3. Changing the volume ratio between methanol/acetonitrile from 60:40 to 50:50 (v/v) allowed to obtain the separation of di-, tri-, and tetrasaccharides labeled by ethyl 4-aminobenzoate in less than 10.5 min.

Extraction and Characterization of Polyphenol Oxidase from Plant Materials: A Review

Polyphenol oxidase (PPO) is a copper-containing enzyme that can be used for different applications including wastewater treatment and biosensing. Given these wide arrays of application, the reaction and biochemical characteristics of the enzyme must be known to further determine its other applications and to control the essential factors during processing. The purpose of this research was to review the different factors that influence the effective extraction and characterization of PPO from plant materials. The pH of the extraction mixture, extraction temperature, type of buffer, mass to solvent ratio, extraction time, and additives are the factors that influence the effective extraction of PPO from plant materials. Since PPOs taken from different plant sources have varied protein structures, these factors have different effects during extraction. The isolated PPO from the extraction process can be characterized based on its activity as a function of pH, temperature, and type of substrate, and on the values of its kinetic parameters (Km and Vmax). PPO isolated from different plant sources shows varied optimum pH, optimum temperature, substrate affinity, and kinetic parameter values.

Using Gold Nanoparticles for Ultra-trace Spectrophotometric Determination of Sitagliptin Drug in Various Real Samples

Background: The determination of trace drugs in aquatic environments is important. For this purpose, many methods such as High Performance Liquid Chromatography (HPLC) and gas chromatography mass spectrometry (GC/MS) have been used. Objective: This study introduces a simple, sensitive, and rapid colorimetric method for the spectrophotometric determination of sitagliptin (STG) in drinking water, tablet, human plasma, and human urine using gold nanoparticles (AuNPs). Methods: The Surface Plasmon Resonance (SPR) property of AuNPs and the interaction between STG and AuNPs are the base of the colorimetric method. The addition of STG into AuNPs led to the aggregation of AuNPs. Transmission Electron Microscopy (TEM) proved the aggregation of AuNPs in the presence of STG. Also, the size of the nanoparticles distribution was evaluated by Dynamic Light Scattering (DLS). In addition, Fourier-Transform Infrared Spectrophotometer (FTIR) was used to study the chemical structure of AuNPs, STG, and AuNPs in the presence of STG. Results: The parameters that affect the absorbance such as pH, type and volume of buffer, AuNPs concentration, interaction time, ionic strength, and interfering ions were investigated and optimized. Under the optimum conditions, the determination of STG was performed via this method over the range of 50-300 μgL-1 (R2=0.9941) with the Limit of Detection (LOD) and Limit of Quantification (LOQ) of 1.23 and 1.39 μgL-1, respectively. Conclusion: Eventually, the results showed that the proposed method has a high potential for simple, rapid, sensitive, and accurate determination of STG.

Photobioelectrochemical hybrid systems: Light-driven biotransformation

<p indent=0mm>Due to the high activity, excellent selectivity, mild reaction condition, and diverse function, biocatalysis has been recognized as a green tool for chemical synthesis. Especially with the progress in biotechnology (such as directed evolution and genetic engineering), it has become possible for biocatalysis to be an environmentally friendly alternative to traditional chemical synthesis processes. Redox reaction is an important category for the industrial application of biocatalysts. In enzymatic redox processes, oxidoreductases are driven to catalyze substrate conversion by consuming redox equivalents. To this end, it is a key issue to efficiently and economically supply redox equivalents for the enzymes. Photocatalysis has attracted much attention for its economic feasibility and environmental compatibility. As semiconductor photocatalysts that can utilize visible light are studied and developed, it can be expected to use clean, abundant, and sustainable solar energy to replace fossil fuel. Photoelectrochemical cells are a kind of configuration that can extract electrons from water by absorbing light energy (and electricity). The photogenerated electrons could be provided to biocatalysts in the form of reducing equivalents. Thus, by constructing photobioelectrochemical hybrid systems (hereafter noted as PBEC), the advantages of both photoelectrochemical and enzymatic catalysis could be combined, achieving a green process of continuous light-driven biotransformation. Microbes can be regarded as a “bag of enzymes” and are also widely studied in PBEC. Compared with enzymes, microbes have strong stability and good metabolic plasticity; however, the drawbacks are the requirement for continuous nutrition and energy supply, and relatively low specificity of products. PBEC has many practical bright sides. First, since the quasi-Fermi level of electrons can be adjusted by applying an external bias, water can be used to provide excited electrons, which means chemical electron donors (e.g., triethanolamine) are not required in such systems, avoiding side-product accumulation or side reactions. Second, the photocatalytic reaction and the biocatalytic one in a PBEC are generally compartmentalized into two chambers by a semi-permeable membrane. The electrons transfer through external wires, which connect the electrodes. Separating the anodic and cathodic reactions (i.e., water oxidation and biocatalytic reduction) can prevent the damage to biocatalysts or products caused by photogenerated oxidative holes or O₂ evolved from water splitting. In addition, the separation allows attempts to use various collocations of different photocatalysts and biocatalysts, as well as optimizations (such as buffer type, temperature, pH, illumination) in a single chamber without influencing the other one. Photoelectrodes and biocatalysts are two core functional components in a PBEC. The photoelectrode captures light energy and generates reducing equivalents, which are subsequently used by biocatalysts for bio-converting substrates to products. In this review, we summarize recent advances in this newly emerging field of PBEC. The first chapter discusses the principles and related studies for choosing photoelectrode materials. Biocatalysts employed in PBEC can be divided into two categories: enzymes and microbes. Based on different biocatalysts, representative works and some optimization strategies are introduced. Finally, prospects for future study and development of PBEC are given.

Artificial neural networks in tandem with molecular descriptors as predictive tools for continuous liposome manufacturing

The current study utilized an artificial neural network (ANN) to generate computational models to achieve process optimization for a previously developed continuous liposome manufacturing system. The liposome formation was based on a continuous manufacturing system with a co-axial turbulent jet in a co-flow technology. The ethanol phase with lipids and aqueous phase resulted in liposomes of homogeneous sizes. The input features of the ANN included critical material attributes (CMAs) (e.g., hydrocarbon tail length, cholesterol percent, and buffer type) and critical process parameters (CPPs) (e.g., solvent temperature and flow rate), while the ANN outputs included critical quality attributes (CQAs) of liposomes (i.e., particle size and polydispersity index (PDI)). Two common ANN architectures, multiple-input-multiple-output (MIMO) models and multiple-input–single-output (MISO) models, were evaluated in this study, where the MISO outperformed MIMO with improved accuracy. Molecular descriptors, obtained from PaDEL-Descriptor software, were used to capture the physicochemical properties of the lipids and used in training of the ANN. The combination of CMAs, CPPs, and molecular descriptors as inputs to the MISO ANN model reduced the training and testing mean relative error. Additionally, a graphic user interface (GUI) was successfully developed to assist the end-user in performing interactive simulated risk analysis and visualizing model predictions.

Decomposition Behavior of Solid Peroxides: Effect of Ph, Ions and Buffer Composition

The ability of solid peroxides to provide sustained release of both oxygen and H 2 O 2 as well as other reactive oxygen species makes them potentially suitable for different therapeutic applications. ROS-related therapies and oxygen delivery are the most researched functions of solid peroxides. This study compared for the first-time decomposition products of CaO 2 , MgO 2 , ZnO 2 , Na 2 CO 3 .1.5H 2 O 2 and H 2 O 2 across an extreme pH range that could still be considered relevant to some biological applications (pH 5-9). We identified a strong effect of both pH and buffer type on both the extent of decomposition and decomposition product thereby establishing design parameters for intentional release of specific decomposition species. Cytotoxicity surprisingly was not only related to basicity of metal hydroxides. We discuss factors that are likely to alter decomposition profiles between in vitro and in vivo systems.

Interplay of Various Charge Sources in AlGaN/GaN Epi-Stack Governing HEMT Breakdown

In this work, we have revealed the interplay of various charge sources (surface, polarization, and buffer) and their relative concentrations across the AlGaN/GaN epi-stack governing the electric field distribution and the breakdown mechanism in high electron mobility transistors (HEMTs). The investigations are carried out for Schottky, metal-insulator-semiconductor (MIS), and p-GaN gate stacks while accounting for possible GaN buffer types (Fe-doped and C-doped). A strong correlation between 3-terminal (3T) breakdown voltage, gate design, and relative concentration of various charges was found. % increase in 3T breakdown voltage when physical dimensions were doubled was also found to be strongly correlated with the relative concentration of various charges for both Fe- and C-doped buffer HEMTs. On the other hand, the 2T (source–drain, without gate, and GaN channel below gate) breakdown voltage was independent of all other parameters except buffer properties and physical dimensions. Physical insights are developed to explain the dependence of electric field distribution, carrier injection, and HEMT breakdown on the surface states, polarization charge, and buffer traps, as well as their relative concentrations for both the buffer types and all three gate types. These insights will help to design efficient surface passivation schemes and resolve ambiguities, often observed in experiments, in terms of location of peak electric field (drain side, or gate side or both) as well as OFF-state conduction and breakdown mechanism (gate injection, or punchthrough, or parasitic conduction through buffer or avalanche generation).

Subcutaneous Injection Site Pain of Formulation Matrices

The objective of this work was to systematically evaluate the effects of formulation composition on subcutaneous injection site pain (ISP) using matrices comprising of common pharmaceutical excipients. Two randomized, blinded, crossover studies in healthy subjects were conducted at a single site, where subjects received 1mL SC injections of the buffer matrices. ISP intensity was measured using a 100mm visual analogue scale (VAS), which was then analyzed via heatmap, categorical grouping, subgroup analysis, and paired delta analysis. Buffer type, buffer concentration and tonicity agent showed a substantial impact on ISP. Citrate buffer demonstrated a higher ISP than acetate buffer or saline). The 20mM citrate buffer was more painful than 10 or 5mM citrate buffers. NaCl and propylene glycol were significantly more painful than sugar alcohols (mannitol, sucrose, trehalose or glycerol). Histidine buffers exhibited ISP in the descending order of 150mM > 75mM > 25mM > 0mM NaCl, while histidine buffers containing Arginine-HCl at 0, 50, or 150mM all showed very low ISP. Histidine buffer at pH6.5 showed a lower ISP than pH5.7. This systematic study via orthogonal analyses demonstrated that subcutaneous ISP is significantly influenced by solution composition.

Bare Iron Oxide Nanoparticles as Drug Delivery Carrier for the Short Cationic Peptide Lasioglossin.

New drug delivery systems are a potential solution for administering drugs to reduce common side effects of traditional methods, such as in cancer therapy. Iron oxide nanoparticles (IONs) can increase the drugs’ biological activity through high binding efficiency and magnetically targeted drug delivery. Understanding the adsorption and release process of a drug to the carrier material plays a significant role in research to generate an applicable and controlled drug delivery system. This contribution focuses on the binding patterns of the peptide lasioglossin III from bee venom on bare IONs. Lasioglossin has a high antimicrobial behavior and due to its cationic properties, it has high binding potential. Considering the influence of pH, the buffer type, the particle concentration, and time, the highest drug loading of 22.7% is achieved in phosphate-buffered saline. Analysis of the desorption conditions revealed temperature and salt concentration sensitivity. The nanoparticles and peptide-ION complexes are analyzed with dynamic light scattering, zeta potential, and infrared spectroscopy. Additionally, cytotoxicity experiments performed on Escherichia coli show higher antimicrobial activity of bound lasioglossin than of the free peptide. Therefore, bare IONs are an interesting platform material for the development of drug-delivery carriers for cationic peptides.