Bovine Serum Albumin Concentration Research Articles

Influence of proteins on the dielectric characteristics of 5CB and 8CB liquid crystals

ABSTRACT In this paper, we study the influence of the protein Bovine Serum Albumin (BSA) on the dielectric properties of liquid crystals (LCs) such as 4-cyano-4-pentyl biphenyl (5CB) and Octyl-4-biphenylcarbonitrile (8CB). Studying the effect of proteins on the dielectric properties of LC is essential for both fundamental research and practical applications in material science, biomedical engineering, biotechnology, and optoelectronic devices. It helps understand the protein behaviour on the surface of LCs, which offers an opportunity to develop novel sensing platforms. A polarising optical microscope (POM) was used to examine the correlation between textures formed by LCs interacting with different concentrations of BSA. In the dielectric studies, dielectric parameters such as impedance (Z), real (Z’) and imaginary (Z’’) parts of the impedance, and the tangential loss (tan δ) were measured. The investigation involved analysing relaxation times using the collected data, revealing distinct behaviours between 5CB and 8CB liquid crystals. Bode and Nyquist’s plots were constructed and analysed to investigate the changes LCs undergo while interacting with BSA. An equivalent electrical circuit (EEC) was constructed using Bode and Nyquist data, from which circuit element values were successfully extracted. The results obtained from the POM studies and the interferences drawn from the EIS can help enhance the performance of protein-based liquid crystal devices.

Effect of Protein (Bovine Serum Albumin) Content on the Frictional Behaviour of Soft Contact Lenses Using a Dynamic Oscillating Tribometer

Proteins can adsorb on the surface of materials, such as soft contact lenses (SCLs), and can affect the hydrophobicity, roughness, and surface properties of the contact lenses (CLs), which, in turn, can influence the friction between the lenses and the ocular surface. Excessive friction between contact lenses and the ocular surface can lead to discomfort for the wearer and may cause irritation or inflammation of the cornea, better known as corneal ulcers (keratitis). Bovine Serum Albumin (BSA) is often used as a standard protein in biocompatibility testing of materials, including contact lenses. One standard commercial contact lens was tested under lubricated conditions to access the coefficient of friction (CoF). The contact was lubricated with a tear-like fluid (TLF) solution containing six different concentrations of BSA. In all cases, good linearity of the results of the friction force was verified, suggesting that the first friction law can be applied to determine the value of the coefficient of friction. It was found that friction increases with the increase in protein concentration.

Effect of different concentrations of bovine serum albumin on freezing of goat semen

Objective. Evaluate the effect of Bovine Serum Albumin (BSA) concentration on the freezability of goat semen in a Tris-based lyophilized preservative-diluter, without performing seminal washing, compared with a control preservative-diluter of lactose-skimmed milk (DC), removing the seminal plasma by centrifugation. Materials and methods. It will cover 90 ejaculates, volume, motility, concentration, viability, and sperm morphology. The fit ejaculates were mixed and the pool divided into five portions, each receiving one of 4 lyophilized combinations based on Tris-Glucose-Ac. Citrus and Glycerol with different concentrations of BSA (0.1%, 0.5%, 1% and 2%) or DC. It was frozen in 0.1 ml pellets in nitrogen vapors, and after 2 min., They were stored in liquid nitrogen until thawing 7 days later, the following were determined: motility percentage (30, 120 and 240 minutes), viability, damaged acrosomes and total anomalies (30 and 120 minutes) and were compared using a Binary Logistic Regression model. Results. The highest sperm motility and viability (p <0.05) in the three times was for 0.5%, 1% and 2% of BSA, which were higher than 0.1% of BSA and DC. Damages acrosome and total abnormalities at 30 and 120 minutes were lower (p <0.05) for 0.5%, 1% and 2% of BSA compared to 0.1% and DC. Conclusion. The cryopreservation of goat semen does not require seminal washing by centrifugation if 0.5-2% BSA is used as a membrane protector in a lyophilized dilute-conservative based on Tris-Glucose-Citric Acid and Glycerol.

Plug-and-Play Fabry-Perot interferometric biosensor with Vernier effect for label-free detection of bovine serum albumin

In this work, we demonstrate a novel plug-and-play integrated optical fiber sensing structure based on femtosecond laser micromachining and Vernier effect for label-free detection of bovine serum albumin (BSA) concentration. A rectangular microgroove is etched in the hollow-core fiber (HCF), and a U-shaped fiber is formed to design an open microcavity Fabry-Perot interferometer (FPI), in which the liquid can flow sufficiently into the microcavity as the sensing medium. Through simulation and experimental testing, it has been proven that the sensor can achieve high sensitivity and precision detection of BSA concentration. The refractive index measurement sensitivity is as high as 12308.97nm/RIU, and the BSA concentration measurement sensitivity is 1.972nm/(mg/ml), with an average absolute percentage error of 2.03%. The performance test shows that the sensor has the advantages of strong stability, good repeatability, high measurement accuracy and fast liquid exchange, it can be used as a new sensing method to achieve real-time, online and fast detection of weakly changing biomass.

The influence of culture medium and protein supplementation on the sensitivity of the Mouse Embryo Assay to detect Triton X-100

Research question: To what extent does the type and concentration of protein and the type of culture medium affect the sensitivity of Mouse Embryo Assays (MEAs) to detect Triton X-100 (TX-100) in culture media?Design: The effect of bovine (BSA) and human serum albumin (HSA) concentration was assessed by supplementing media with 0.5 or 5mg/ml. KSOM and HTF were used as complex and simple-formulation media, respectively. Variables were combined forming study groups where embryos were cultured in tested media spiked with a sublethal TX-100 concentration. The conditions of greatest sensitivity were determined by statistically comparing blastocyst formation rates and total cell counts between groups.Results: Although all the study groups showed an equal capacity of sustaining a proper embryo development, the reported sensitivity of the MEA differed between groups when subjected to TX-100. HTF significantly conferred greater sensitivity than KSOM regardless of the amount/type of protein used, whereas medium supplementation with 5mg/ml BSA rather than 0.5mg/ml also resulted in significantly higher sensitivity regardless of the type of medium used. This increase in concentration also resulted in a higher sensitivity when supplementing HTF with HSA. BSA groups provided more sensitivity than its HSA-counterparts except for the group 0.5mg/ml-KSOM. Cell counting analysis did not provide further significant conclusions.Conclusions: For TX-100 detection within culture medium, the concentration and type of protein supplementation and the culture medium type impact directly on MEA sensitivity. These results could help to standardize MEA protocols and increase their ability to detect sublethal amounts of embryotoxic substances, especially TX-100, avoiding possible clinical harmful effects.

Kinetic Study of the Esterase-like Activity of Albumin following Condensation by Macromolecular Crowding.

The ability of bovine serum albumin (BSA) to form condensates in crowded environments has been discovered only recently. Effects of this condensed state on the secondary structure of the protein have already been unraveled as some aging aspects, but the pseudo-enzymatic behavior of condensed BSA has never been reported yet. This article investigates the kinetic profile of para-nitrophenol acetate hydrolysis by BSA in its condensed state with poly(ethylene) glycol (PEG) as the crowding agent. Furthermore, the initial BSA concentration was varied between 0.25 and 1 mM which allowed us to modify the size distribution, the volume fraction, and the partition coefficient (varying from 136 to 180). Hence, the amount of BSA originally added was a simple way to modulate the size and density of the condensates. Compared with dilute BSA, the initial velocity (vi) with condensates was dramatically reduced. From the Michaelis-Menten fits, the extracted Michaelis constant Km and the maximum velocity Vmax decreased in control samples without condensates when the BSA concentration increased, which was attributed to BSA self-oligomerization. In samples containing condensates, the observed vi was interpreted as an effect of diluted BSA remaining in the supernatants and from the condensates. In supernatants, the crowding effect of PEG increased the kcat and catalytic efficiency. Last, Vmax was proportional to the volume fraction of the condensates, which could be controlled by varying its initial concentration. Hence, the major significance of this article is the control of the size and volume fraction of albumin condensates, along with their kinetic profile using liquid-liquid phase separation.

Dissimilar effects of the hydrophilic carbon dots on the amyloid aggregation of two model proteins and the mechanism discussion.

Many proteins could aggregate into amyloid fibrils under certain conditions. However, the aggregation process and morphology of the fibrils may be significantly different because of the distinct protein structure. In this article, the hydrophilic carbon dots (Lys-CA-CDs) were prepared using lysine (Lys) and citric acid (CA) as reactant under the assistance of a microwave. The dissimilar modulation effect of Lys-CA-CDs on the aggregation process of distinct structure protein was further investigated, where bovine serum albumin (BSA) and hen egg white lysozyme (HEWL) were chosen as model proteins. All results showed that Lys-CA-CDs displayed the contrary influence on the aggregation process of BSA and HEWL. Lys-CA-CDs could induce BSA to aggregate into more wormlike fibrils and inhibit the aggregation of HEWL into hair-like fibrils. The influence on the aggregation process of BSA may be assigned to the increased concentration of BSA around the Lys-CA-CDs caused by their interaction. However, inserting of Lys-CA-CDs into the inner structure of HEWL led to the change of protein secondary structure. The change of secondary structure further made it difficult for HEWL to aggregate into fibrils and Lys-CA-CDs showed the inhibition effect on HEWL aggregation.

Clarifying the role of carboxyl functionality in squaraines towards aggregation and self-assembly through photophysical characterization and BSA interactions

The demand for near-infrared (NIR) probes with robust and stable fluorescence signals has surged, driven by their applications in optical sensing and bioimaging. Squraine dyes as NIR fluorescent probes have gained significant traction. However, understanding their behavior in aqueous media is important for their successful application. Herein we report the synthesis and photophysical characterization of carboxy-functionalized unsymmetrical squaraine dyes capable of light absorption and emission in the near-infrared (NIR) wavelength region. Structural variations in alkyl chain length, and spacer chain length between the primary chromophore and –COOH group were systematically introduced to investigate their impact on self-assembly in aqueous media leading to dye aggregation and their differential interactions with Bovine Serum Albumin (BSA) as a model protein. In phosphate buffer (PB) the absorption intensity decreased drastically along with pronounced shoulders due to dye aggregation leading to complete fluorescence quenching. However, in the presence of BSA, the intensity of shoulder bands reduced coupled with a sharp increase in the absorption associated with monomeric dye with the increasing concentration of BSA, indicating the prevention of dye aggregation owing to dye-BSA interactions. The prevention of dye aggregation due to dye-BSA interaction also led to a tremendous increase in the fluorescence intensities as a function of the increasing BSA concentrations. Site-selective study off BSA showed that these dyes bind preferably at Site-II using hydrophilic interactions. Thus, these dyes show great potential as FRET or fluorescent on/off probes for biosensing, non-covalent labeling of proteins, and fluorescent probes for bioimaging.

Unlocking Potential: Low Bovine Serum Albumin Enhances the Chondrogenicity of Human Adipose-Derived Stromal Cells in Pellet Cultures.

Bovine serum albumin (BSA) plays a crucial role in cell culture media, influencing cellular processes such as proliferation and differentiation. Although it is commonly included in chondrogenic differentiation media, its specific function remains unclear. This study explores the effect of different BSA concentrations on the chondrogenic differentiation of human adipose-derived stromal/stem cells (hASCs). hASC pellets from six donors were cultured under chondrogenic conditions with three BSA concentrations. Surprisingly, a lower BSA concentration led to enhanced chondrogenesis. The degree of this effect was donor-dependent, classifying them into two groups: (1) high responders, forming at least 35% larger, differentiated pellets with low BSA in comparison to high BSA; (2) low responders, which benefitted only slightly from low BSA doses with a decrease in pellet size and marginal differentiation, indicative of low intrinsic differentiation potential. In all cases, increased chondrogenesis was accompanied by hypertrophy under low BSA concentrations. To the best of our knowledge, this is the first study showing improved chondrogenicity and the tendency for hypertrophy with low BSA concentration compared to standard levels. Once the tendency for hypertrophy is understood, the determination of BSA concentration might be used to tune hASC chondrogenic or osteogenic differentiation.

Abstract 5755: Development of paclitaxel-loaded nanoparticles with high charge density

Abstract Paclitaxel (PTX) is a potent anticancer agent with desirable efficacy against pancreatic cancer when used in conjunction with gemcitabine. The current formulation of nab-paclitaxel shows an improved safety profile compared to the conventional PTX, but the highly potent nature of paclitaxel still poses a problem as it leads to severe side effects, such as neutropenia and neuropathy, calling for the development of carriers with better targeting ability. Tumor treating fields (TTFields) is a new noninvasive treatment modality which disrupts the mitosis of a cell with alternating electric fields with low and intermediate frequency (100 - 500 kHz). Highly polar or charged macromolecules are impacted by the presence of TTFields as they lose random motions essential for mitosis. In previous work on the formulation of self-assembling cationic-anionic nanoparticles (S-CAP NPs), gemcitabine was successfully loaded into the nanoparticles with optimal particle size, stability, and release profile responsive to TTFields. In this study, S-CAP NPs were developed with biocompatible polymers, DEAE-dextran (Ddex) and bovine serum albumin (BSA), via a relatively green method to load paclitaxel with minimal use of organic solvents. Based on the previous study and the proof of concept, it can be hypothesized that the S-CAP NPs can successfully carry PTX and release it in the presence of TTFields. Various parameters, such as temperature, rpm, and concentration, were tested to optimize the size, PDI, zeta potential, and stability of the particles. The HPLC method was developed for PTX and used to analyze drug loading. Numerous compositions of BSA and Ddex were tested, and the ratio of 10:1 (BSA:Ddex) developed the best parameters of the S-CAP NPs. At 50 °C, the zeta potential of the particle was -3.55 ± 0.23 mV for the NPs, but the particles agglomerated over time as BSA precipitates were formed. At -15°C, the particle size was 302.9 ± 2.0 nm (PDI = 0.307 ± 0.038). Varying concentrations of BSA and Ddex showed the formation of S-CAP NPs at lower concentration. The optimal particle was formed at room temperature (RT) with BSA 0.1% and Ddex 0.01% with a size of 264.6 ± 19.7 nm (PDI = 0.079 ± 0.028) and a zeta potential of -14.67 ± 0.07 mV. The particles showed desirable stability for 48 hours. The HPLC analysis (Agilent, Phenomenex C18, 150 x 4.6 mm, 5 micron) was tested for validity and robustness (r2 = 0.9996). Currently, the drug loading was achieved at 1.9% and the optimization studies are ongoing. In vitro cell viability assay (MTS) with and without TTFields is under exploration. With the successful formulation of PTX-loaded S-CAP NPs, co-loading PTX and gemcitabine can be explored to reduce the treatment burden of the patients. Citation Format: Katherine Y. Bang, Preshita P. Desai. Development of paclitaxel-loaded nanoparticles with high charge density [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5755.

Probing berberine syringate-bovine serum albumin interactions by multi-spectroscopic, conductimetric, volumetric and molecular docking methods

In this paper, a new berberine-based salt berberine syringate ([BBR][SA]) was synthesized and [BBR][SA]-bovine serum albumin (BSA) interactions were investigated by various techniques like UV–visible absorption, fluorescence spectroscopy, Fourier transform infrared spectroscopy (FT-IR), volumetry and conductimetry. Using the experimental values of density and conductivity, the specific volume of BSA and the critical aggregation concentration of [BBR][SA] were derived. From the variation trends of specific volume for BSA with [BBR][SA] concentrations, it was observed the predominate ionic interaction/dehydration effect at small [BBR][SA] concentration and the non-polar interaction/hydration phenomenon at higher [BBR][SA] concentration for the binding of [BBR][SA] with BSA, as well as hydration shell structure changes at different temperatures in the medium with different pH values. Aggregation of [BBR][SA] is slowed by increasing concentration of BSA and temperature. The thermodynamic parameters of aggregation process have been exploited to gain more information on the interaction of [BBR][SA] with BSA. UV–vis absorption, multiple fluorescence spectroscopy (steady-state spectroscopy, synchronous fluorescence, three-dimensional fluorescence), and FT-IR have been utilized to understand the interaction mechanisms and binding strength between the two molecules. [BBR][SA] quenches the fluorescence of BSA through static quenching mechanism. The 1:1 complex between [BBR][SA] and BSA with a strong affinity was formed. The changes in microenvironment and conformation of BSA caused by [BBR][SA] were revealed by synchronous fluorescence spectra, 3D fluorescence maps and FT-IR. The binding average distance from [BBR][SA] to BSA (2.83 nm) was obtained based on the theory of Förster energy transfer. Competitive binding experiment confirms [BBR][SA] binding to Sudlow site I (sub-domain IIA) of BSA. In addition, molecular docking was generated to provide valuable information about the available binding sites of [BBR][SA] on BSA and the types of binding forces.

Load-bearing columns inspired fabrication of ductile and mechanically enhanced BSA hydrogels

Currently, protein-based hydrogels are widely applied in soft materials, tissue engineering and implantable scaffolds owing to their excellent biocompatibility, and degradability. However, most protein-based hydrogels are soft brittle. In this study, a ductile and mechanically enhanced bovine serum albumin (BSA) hydrogel is fabricated by soaking the a 1-(3-dimethylaminopropyl)-3ethylcarbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) induced BSA hydrogel in (NH4)2SO4 solution. An EDC/NHS coupling reaction induce protein coupling reactions that cause the BSA skeleton to resemble architectural load-bearing walls, protecting the integrity of the hydrogel and preventing collapse. The effects of the BSA and (NH4)2SO4 concentrations on the hydrogel mechanics are evaluated, and the possible strengthening mechanism is discussed. Besides, the highly kosmotropic ions greatly enhance the hydrophobic interaction within BSA gels and dehydration effect and their mechanical properties were significantly enhanced. The various mechanical properties of hydrogels can be regulated over a large window by soaking hydrogels into various ions. And most of them can be washed away, maintaining high biocompatibility of the protein. Importantly, the protein hydrogels prepared by this strategy could also be modified as strain sensors. In a word, this work demonstrates a new, universal method to provide multi-functional, biocompatible, strength enhanced and regulable mechanical pure protein hydrogel, combining the Hofmeister effect with -NH2/-COOH association groups.

The dynamics of PEG‐coated nanoparticles in concentrated protein solutions up to the molecular crowding range

AbstractPolymer‐coated nanoparticles are widely studied in the context of nanomedicine and it is therefore of utmost importance to understand not only how their structure but also how their colloidal dynamics are affected by physiologically relevant conditions. A characteristic feature of the cytosol of cells is the very high concentration of proteins among other matrix components, often termed macromolecular crowding. Here, the structure and colloidal dynamics of poly(ethylene glycol) (PEG)‐coated gold nanoparticles in the presence of bovine serum albumin (BSA) concentrations ranging from 0 to 265 mg/mL are studied with X‐ray photon correlation spectroscopy. For protein–nanoparticle mixtures with high BSA concentrations, comparable to intracellular levels, a significant deviation of the apparent viscosity from expectations for pure BSA solutions is found. The findings strongly indicate that the nanoscopic viscous properties of the dense protein solutions are significantly affected by the nanoparticles. At these high concentrations, the colloidal stability of the samples depends on the molecular weight of the coating PEG–ligand, whereas at lower concentrations no differences are observed.

High-concentration bovine serum albumin enhances fertilization ability of cold-stored rat sperm.

Cold transport of the cauda epididymides is a useful technique for shipping laboratory rat sperm. Cold transport of rat sperm avoids potential risks of microbiological infection, animal escape or death, and animal welfare issues. Previously, we reported that a cold-storage solution containing dimethyl sulfoxide and quercetin maintained the fertility of cold-stored rat sperm. However, cold-stored rat sperm exhibited a decreased fertilization rate after 24-h storage. To recover the fertility of cold-stored sperm, we focused on the effects of bovine serum albumin (BSA), a cholesterol acceptor that induces sperm capacitation. We sought to determine the optimal concentration of BSA in fertilization medium based on the fertility of cold-stored rat sperm. High concentrations of BSA (40 mg/ml) enhanced the fertilization rate of cold-stored rat sperm and maintained sperm fertility for 144 h. Embryos derived from cold-stored and BSA-treated sperm normally developed into pups after embryo transfer. In summary, high BSA concentrations enhanced the fertility of cold-stored rat sperm and prolonged the storage period to 144 h, thereby expanding the transportable region for genetically engineered rats.

Further study on particle size, stability, and complexation of silver nanoparticles under the composite effect of bovine serum protein and humic acid.

Silver nanoparticles (AgNPs) are widely used due to their unique antibacterial properties and excellent photoelectric properties. Wastewater treatment plants form a pool of AgNPs due to the social cycle of wastewater. During biological treatment processes, the particle size and stability of AgNPs change. We studied the particle size changes and stability of silver nanoparticles in the presence of bovine serum albumin (BSA) and humic acid (HA). The experimental results indicated that silver nanoparticles can complex with the functional groups in BSA. For AgNP-BSA composites, as the BSA concentration increases, the size of the silver nanoparticles first decreases and then increases. AgNPs can combine with the amide, amino, and carboxyl groups in HA. As the concentration of HA increases, the particle size and large particle size distribution of AgNPs increase. This increasing trend is more obvious when the HA concentration is lower than 20 mg L-1. When HA and BSA exist at the same time, HA will occupy the adsorption sites of BSA on the surface of AgNPs, and the AgNP-HA complex will dominate the system. This study aims to provide key operational control strategies for the process operation of wastewater treatment plants containing AgNPs and theoretical support for promoting water environment improvement and economic development such as tourism.

A Fixed-Bed Study on the Feedsorption of BSA Using PKC: Toward the Sustainable Agrosorption of Protein-rich Waste for Enhancing Low Nutritional-value Feed

Palm Kernel Cake (PKC), a by-product of Malaysia's palm oil industry, stands out as a sustainable and cost-efficient feed ingredient. However, its use is nutritionally limited for monogastric animals due to high fiber content and anti-nutritional factors. This groundbreaking study explores the innovative process of 'feedsorption'—a term we have coined under the broader concept of 'agrisorption'—to enhance the nutritional value of PKC. By adsorbing protein-rich agricultural, poultry, and farm animal wastes, represented by bovine serum albumin (BSA), we aim to elevate PKC's protein content. Through detailed experimentation involving varying bed depths (1 cm to 2 cm) and initial BSA concentrations (100 to 500 µg/mL) within fixed-bed columns, our findings reveal that increased bed depths significantly prolong breakthrough and exhaustion times, highlighting improved adsorption efficiency. Yet, depths beyond 1 cm pose a risk of clogging. Higher BSA concentrations were found to accelerate breakthrough, indicating a stronger driving force capable of overcoming mass transfer resistance. The Modified Dose Response (MDR) model outperformed the Thomas model in accurately predicting breakthrough curves across different conditions. This study not only confirms the feasibility of feedsorption to bolster the nutritional profile of low-quality feed using protein-rich waste but also introduces a promising avenue for enhancing sustainable livestock nutrition.

Aggregation behavior of polystyrene nanoplastics: Role of surface functional groups and protein and electrolyte variation

Aggregation kinetics of plastics are affected by the surface functional groups and exposure orders (electrolyte and protein) with kinds of mechanisms in aquatic environment. This study investigates the aggregation of polystyrene nanoplastics (PSNPs) with varying surface functional groups in the presence of common electrolytes (NaCl, CaCl2, Na2SO4) and bovine serum albumin (BSA). It also examines the impact of different exposure orders, namely BSA + NaCl (adding them together), BSA → NaCl (adding BSA firstly and then NaCl), and NaCl → BSA (adding NaCl firstly and then BSA), on PSNPs aggregation. The presence of BSA decreased the critical coagulation concentration in NaCl (CCCNa+) of the non-modified PS-Bare from 222.17 to 142.81 mM (35.72%), but increased that of the carboxyl-modified PS-COOH from 157.34 to 160.03 mM (1.71%). This might be ascribed to the thicker absorbed layer of BSA onto the PS-Bare surface, known from Ohshima's soft particle theory. Their aggregation in CaCl2 was both increased because of Ca2+ bridging. Different from the monotonous effects of BSA on PS-Bare and PS-COOH, BSA initially facilitated PS-NH2 aggregation via patch-charge attraction, then inhibited it at higher salt levels through steric repulsion. Furthermore, exposure orders had no significant effect on PS-Bare and PS-COOH, but had a NaCl concentration-dependent impact on PS-NH2. At the low NaCl concentrations (10 and 100 mM), no obvious influence could be observed. While, at 300 mM NaCl, the high concentrations of BSA could not totally stabilize the salt-induced aggregates in NaCl → BSA, but could achieve it in the other two orders. These might be attributed to the electrical double layer compression by NaCl, “patch-charge” force and steric hindrance by BSA. These experimental findings shed light on the potential fate and transport of nanoparticles in aquatic environments.

Drug-Releasing Tannic Acid-Mediated Adhesive PEG Hydrogel for Porous Titanium Implants.

Porous titanium implants are commonly utilized for orthopedic surgery because they can mimic the mechanical properties and porous structure of human bone. However, the bioinertness of titanium (Ti) has been reported to obstruct biointegration processes, resulting in slower bone repair. Here, we propose a localized drug delivery system on Ti surfaces using adhesive hydrogel to enhance biological-Ti interactions. The hydrogel was fabricated from polyethylene glycol (PEG), which was cross-linked by the complex of tannic acid (TA) and 1,4-phenylenediboronic acid (PDBA) and stabilized by bovine serum albumin (BSA). The hydrogel was formed and attached to a Ti plate to investigate stability, biodegradability, controlled drug release, and biocompatibility. The stability and biodegradability of the hydrogel could be tuned by adjusting the concentrations of BSA and TA. The hydrogel lasted and remained adhered to the Ti surface after being submerged in PBS for at least 15 days. The controlled release of strontium ranelate (SrRan) and the release mechanism depended on the amount of TA since it was found to govern the hydrogel integrity and pore size. Additionally, in vitro biocompatibility was validated using L929 fibroblast and MC3T3-E1 osteoblast cells that showed greater than 70% viability. The adhesive hydrogel was further studied by injecting it into a 3D-printed Ti-scaffold that contained a porous structure mimicking natural human bone. The hydrogel completely filled and adhered to the inner porous structure of the scaffold. The biodegradation and drug release of the hydrogel in the scaffold occurred at a slower rate, suggesting sustainable drug release that is suitable for bone cell regeneration. The overall results in biodegradability, controlled drug release, and biocompatibility demonstrate the great potential of the drug-releasing TA-mediated adhesive PEG hydrogel as a Ti-enhancing biomaterial that supports osseointegration.

Photophysical Characterization and Biointeractions of NIR Squaraine Dyes for in Vitro and in Vivo Bioimaging.

The increasing demand for reliable near-infrared (NIR) probes exhibiting enduring fluorescence in living systems and facile compatibility with biomolecules such as peptides, antibodies or proteins is driven by the increasing use of NIR imaging in clinical diagnostics. To address this demand, a series of carboxy-functionalized unsymmetrical squaraine dyes (SQ-27, SQ-212, and SQ-215) along with non-carboxy-functionalized SQ-218 absorbing and emitting in the NIR wavelength range were designed and synthesized followed by photophysical characterization. This study focused on the impact of structural variations in the alkyl chain length, carboxy functionality positioning, and spacer chain length on dye aggregation and interaction with bovine serum albumin (BSA) as a model protein. In phosphate buffer (PB), the absorption intensity of the dyes markedly decreased accompanied by pronounced shoulders indicative of dye aggregation, and complete fluorescence quenching was seen in contrast to organic solvents. However, in the presence of BSA in PB, there was a enhancement in absorption intensity while regaining the fluorescence coupled with a remarkable increase in the intensity with increasing BSA concentrations, signifying the impact of dye-BSA interactions on preventing aggregation. Further analysis of Job's plot unveiled a 2:1 interaction ratio between BSA and all dyes, while the binding studies revealed a robust binding affinity (Ka) in the order of 107/mol. SQ-212 and SQ-215 were further tested for their in vitro and in vivo imaging capabilities. Notably, SQ-212 demonstrated nonpermeability to cells, while SQ-215 exhibited easy penetration and prominent cytoplasmic localization in in vitro studies. Injection of the dyes into laboratory mice showcased their efficacy in visualization, displaying stable and intense fluorescence in tissues without toxicity, organ damage, or behavioral changes. Thus, SQ-212 and SQ-215 are promising candidates for imaging applications, holding potential for noninvasive cellular and diagnostic imaging as well as biomarker detection when coupled with specific vectors in living systems.

Cholesteric nanostructure biosensors on flexible paper fibres for disease detection through label-free techniques and image analysis

ABSTRACT We have achieved a successful synthesis of a label-free, flexible, portable, and colour-indicating biosensor using cholesteric nanostructure liquid crystals (LCs), commonly referred to as cholesteric LCs (CLCs), on paper fibres. This innovative approach holds significant promise for rapid screening in precision medicine and other applications. We incorporated optically active nematic LCs in various configurations within CLCs, allowing them to rotate along different axes. When exposed to light, these LCs reflected light at specific wavelengths. By employing polarised optical microscopy and a charged couple device (CCD), we conducted titration experiments with bovine serum albumin (BSA) on the paper substrate and quantified protein concentrations based on the observed colour shifts. Utilising internal Python pixel analysis software, we evaluated the red, green, and blue colour components, which served as biomarkers for different BSA concentrations. Our results demonstrated a linear correlation between BSA concentration and colour variations. This CLC-based paper-substrate biosensor exhibits the potential to efficiently screen a large number of samples, thereby enhancing the diagnostic accuracy in clinical settings. Combining the colour-indicating and quantifiable attributes of CLCs with the affordability and portability of paper substrates, we have developed a versatile biosensor. Its ease of use, rapid response, and high sensitivity make it a promising tool for future disease detection endeavours.