Phosphate-buffered Saline Medium Research Articles

Design of double functionalized carbon nanotube for amphotericin B and genetic material delivery

In the present work, single wall carbon nanotubes (SWCNT) were successively functionalized with phospholipid DSPE-PEG carboxylic acid, and then, with ethylenediamine (EDA), to obtain double functionalized single wall carbon nanotube (DFSWCNT). Then, DFSWCNT was applied as a carrier for delivering amphotericin B (Amb) and EGFP plasmid. FSWCNT’s concentration obtained via UV–visible analysis was 0.99 mg/mL. The TGA analysis results provided the lost weights of DSPE-PEG-COOH, EDA, Amb and SWCNT impurities. XPS results showed that carbon atoms’ percentage decreased during the functionalization processes from 97.2% (SWCNT) to 76.4% (FSWCNT) and 69.9% (DFSWNCT). Additionally, the oxygen atoms’ percentage increased from 2.3% (SWCNT) to 21% and 22.5% for FSWCNT and DFSWCNT, respectively. New bonds such as C–N and N–C=O appeared in the synthesized nanocarrier. The IG/ID ratio in Raman analysis decreased from 7.15 (SWCNT) to 4.08 (FSWCNT). The amount of Amb released to phosphate buffer saline medium was about 33% at pH = 5.5 and 75% at pH = 7.4 after 48 h. CCK8 results confirmed that the toxicity of functionalized SWCNT had decreased. In a 2:1 ratio of DFSWCNT/EGFP plasmid, the cell viability (87%) and live transfected cells (56%) were at their maximum values. The results indicate that carbon nanotubes have the potential to be applied as drug/gene delivery systems with outstanding properties such as high loading capacity and easy penetration to cell membrane.

In vitro biodegradation, cytotoxicity, and biocompatibility of polylactic acid/napier cellulose nanofiber scaffold composites

This study aimed to evaluate the bioactivities and biocompatibilities of porous polylactic acid (PLA) reinforced with cellulose nanofiber (CNF) scaffolds. The in vitro degradation behaviors of the porous PLA/CNF scaffolds were systematically measured for up to 8 weeks in a phosphate-buffered saline medium at 37 °C. The reinforcement of CNF resisted the biodegradation of the scaffolds. The in vitro cytotoxicity and biocompatibility of the scaffolds were determined using the Beas2B American Type Culture Collection cells. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cytotoxicity and proliferation tests showed that the scaffolds were non-toxic, and epithelial cells grew well on the scaffold after 7 days of culture, whereas the percentage of cell proliferation on the PLA/CNF15 scaffold was the largest, 130 %. A scratch wound-healing assay was performed to evaluate the suitability of the scaffolds for cell migration. The results demonstrated that the scaffolds exhibited good cell migration towards nearly complete wound closure.

Effect of Chitosan and Amphiphilic Polymers on the Photosensitizing and Spectral Properties of Rose Bengal.

The influence of chitosan (CS) and amphiphilic polymers (AP: pluronic F108 and polyvinylpyrrolidone (PVP)) on the photocatalytic activity of rose bengal (RB) in a model reaction of tryptophan photo-oxidation in phosphate-buffered saline (PBS) was studied. It was shown that in the presence of CS, the effective rate constant keff of tryptophan photo-oxidation catalyzed by RB in PBS solution decreases by a factor of two. This is due to the ionic interaction of the RB with the chitosan. Rose bengal in a slightly acidic environment (pH 4.5) passes into a neutral lactone form, which sharply reduces the photosensitizing properties of the dye. It was demonstrated that the introduction of AP into a solution containing RB and CS prevents direct interaction between RB and CS. This is evidenced by the presence of photocatalytic activity of the dye in the RB-AP-CS systems, as well as bathochromic shifts of the main absorption bands of the dye, and an increase in the optical density and luminescence intensity of the RB when AP is introduced into a buffer solution containing RB and chitosan. The presence of RB-CS and RB-AP interaction in aqueous and PBS media is confirmed by the increase in the degree of fluorescence anisotropy (r) of these binary systems. In an aqueous solution, the value of r for the RB-F108-CS system decreases by a factor of 3.5 (compared to the value of r for the RB-CS system), which is associated with the localization of the dye in pluronic micelles. In PBS, the fluorescence anisotropy is practically the same for all systems, which is related to the stability of the dye structure in this medium. The presence of interaction between RB and AP in aqueous solutions was confirmed by the proton NMR method. In addition, the formation of RB-F108 macromolecular complexes, which form associates during solution concentration (in particular, during evaporation), was shown by AFM. Such RB-AP-CS systems may be promising for practical application in the treatment of local foci of infections by aPDT.

Antibacterial Activity and Mechanism of Linalool against Shigella sonnei and Its Application in Lettuce

Shigella sonnei (S. sonnei) infection accounted for approximately 75% of annual outbreaks of shigellosis, with the vast majority of outbreaks due to the consumption of contaminated foods (e.g., fresh vegetables, potato salad, fish, beef, etc.). Thus, we investigated the antibacterial effect and mechanism of linalool on S. sonnei and evaluated the effect of linalool on the sensory quality of lettuce. The minimum inhibitory concentration (MIC) of linalool against S. sonnei ATCC 25931 was 1.5 mg/mL. S. sonnei was treated with linalool at 1× MIC for 30 min and the amount of bacteria was decreased below the detection limit (1 CFU/mL) in phosphate-buffered saline (PBS) and Luria-Bertani (LB) medium. The bacterial content of the lettuce surface was reduced by 4.33 log CFU/cm2 after soaking with linalool at 2× MIC. Treatment with linalool led to increased intracellular reactive oxygen species (ROS) levels, decreased intracellular adenosine-triphosphate (ATP) content, increased membrane lipid oxidation, damaged cell membrane integrity, and hyperpolarized cell membrane potential in S. sonnei. The application of linalool to lettuce had no effect on the color of lettuce compared to the control. The sensory evaluation results showed that linalool had an acceptable effect on the sensory quality of lettuce. These findings indicate that linalool played an antibacterial effect against S. sonnei and had potential as a natural antimicrobial for the inhibition of this foodborne pathogen.

Superparamagnetic Tragacanth Coated Fe3O4@SiO2 Nanoparticles for the Loading and Delivery of Metformin.

A novel superparamagnetic nano-composite of Fe3O4@SiO2 coated by tragacanth gum (TG) as a natural product has been prepared. The obtained SiO2@Fe3O4@TG nanoparticles were characterized by Fourier transform infrared spectroscopy, energy dispersive X-ray analysis, scanning electron microscopy and dynamic light scattering analyzer. The magnetic nano-composite was applied for the loading and delivery of metformin, an oral diabetes medicine. The conditions for the loading of the drug were optimized by a central composite design optimization method. The maximum loading efficiency of the sorbent for metformin was obtained at pH 7 and its maximum in-vitro release was achieved at pH 1.6, using a phosphate-buffered saline medium. The loading capacity of the sorbent was dependent on the initial metformin concentration and exceeded to 19.6 mg/g in a 200 mg/L solution. A study of the adsorption isotherms for the drug indicated the best fitting into the Langmuir and Freundlich isotherms at the low and high metformin concentrations, respectively. The results indicated that the prepared Fe3O4@SiO2@TG adsorbent, as a non-toxic and low-cost sorbent, was quite appropriate for drug delivery applications.

In Vitro Study of the Phytochemical Composition and Antioxidant, Immunostimulant, and Hemolytic Activities of Nigella sativa (Ranunculaceae) and Lepidium sativum Seeds.

The Moroccan flora abounds and is an important reserve of medicinal plants. Nigella sativa and Lepidium sativum are plants that are widely used in traditional medicine for their multiple therapeutic properties. The current study aims to highlight the biological activities that can justify and valorize the use of these plants. Flavonoids, total phenols, condensed tannins, and sugars were determined. The biological activities tested were antioxidant by determining the IC50 (defined as the concentration of an antioxidant required to decrease the initial concentration by 50%; inversely related to the antioxidant capacity), hemagglutination, and hemolytic activities. Phytochemical quantification of the seed extracts indicated that the total phenol content was largely similar for both plants and in the order of 10 mg GAE (Gallic acid equivalent)/g. On the other hand, L. sativum seeds registered a higher content of flavonoids (3.09 ± 0.04 mg QE (quercetin equivalent)/g) as compared to Nigella saliva (0.258 ± 0.058). Concerning condensed tannins, N. saliva seeds present a higher amount with a value of 7.2 ± 0.025 mg/g as compared to L. sativum (1.4 ± 0.22 mg/g). Concerning the total sugar content, L. sativum shows a higher content (67.86 ± 0.87 mg/g) as compared to N. sativa (58.17 ± 0.42 mg/g); it is also richer in mucilage with a content of 240 mg as compared to 8.2 mg for N. saliva. Examination of the antioxidant activity using a DPPH (2.2-diphenyl 1-pycrilhydrazyl) test revealed that the EButOH (n-butanol extract) and EAE (ethyl acetate extract) extracts were the most active, with IC50 values of 48.7 and 50.65 μg/mL for the N. sativa extracts and 15.7 and 52.64 μg/mL for the L. sativum extracts, respectively. The results of the hemagglutination activity of the different extracts of the two plants prepared in the PBS (phosphate-buffered saline) medium showed significant agglutination for the L. sativum extract (1/50) compared to the N. sativa extract (1/20). An evaluation of the hemolytic effect of the crude extract of the studied seeds on erythrocytes isolated from rat blood incubated in PBS buffer compared to the total hemolysis induced by distilled water showed a hemolysis rate of 54% for Nigella sativa and 34% for L. sativum. In conclusion, the two plants studied in the current work exhibited high antioxidant potential, which could explain their beneficial properties.

Dual-miRNA-Propelled Three-Dimensional DNA Walker for Highly Specific and Rapid Discrimination of Breast Cancer Cell Subtypes in Clinical Tissue Samples

Dual-miRNA-Propelled Three-Dimensional DNA Walker for Highly Specific and Rapid Discrimination of Breast Cancer Cell Subtypes in Clinical Tissue Samples

Green synthesis of PEG-coated MIL-100(Fe) for controlled release of dacarbazine and its anticancer potential against human melanoma cells

In this study, the potential of using MIL-100(Fe) metal–organic framework (MOF) for loading and controlling the release of dacarbazine (DTIC) was evaluated for in vitro treatment of melanoma. The drug loading was performed during the green synthesis of MIL-100(Fe) in an aqueous media without using any harmful solvents, to obtain MIL-DTIC. The surface of this structure was then coated with polyethylene glycol (PEG) in the same aqueous solution to synthesize MIL-DTIC-PEG. The synthesized samples were characterized using various methods. Their release profile was studied in phosphate-buffered saline (PBS) and simulated cutaneous medium (SCM). The cytotoxicity of DTIC and its nano-MOF formulation were investigated against melanoma A375 cell lines. The results revealed that the PEG coating (PEGylation) changed the surface charge of MOF from −2.8 ± 0.9 mV to −42.8 ± 1.2 mV, which can contribute to the colloidal stability of MOF. The PEGylation showed a significant effect on controlled drug release, especially in SCM, which increases the complete release time from 60 h to 12 days. Moreover, both of the drug-containing MOFs showed more toxicity than DTIC and unloaded MOFs, confirming that the cumulative release of drug and better cellular uptake of NPs lead to increased toxicity.

Effect of Zn and Ga doping on bioactivity, degradation, and antibacterial properties of borate 1393-B3 bioactive glass

Borate 1393-B3 bioactive glasses doped with ZnO or Ga2O3 (1, 3, and 6% mol) were produced by conventional melt quenching. All doped glasses showed in-vitro bioactivity in simulated body fluid (SBF). For the first time, the dissolution behavior of the glasses both in phosphate-buffered saline (PBS) and cell culture medium was investigated. The ion release rate in the cell culture medium increased compared to that in PBS solution. All tested glass compositions, including the parent 1393-B3 glass, showed antibacterial effect against S. aureus and E. coli. The incorporation of Zn and Ga enhanced the viability of MG-63 osteoblast-like cells compared to the base 1393-B3 glass. The results show the potential of Zn and Ga-doped borate glasses in multifunctional tissue engineering applications.

Investigating the degradation behaviour and characteristic changes of phase pure hydroxyapatite (HAp) microsphere scaffolds under static and dynamic conditions

ABSTRACT Hydroxyapatite (HAp) has been widely researched on due to its chemical similarity to native bone. HAp microspheres can encourage good cellular attachment due to their high surface area to volume ratio, facilitating further proliferation and differentiation of cells at later stages. To ensure the reliability and effectiveness of HAp microspheres in physiological conditions, we investigated their behaviour and key characteristic changes in both static and dynamic conditions. We found both environments exhibiting similar results but noticeably the microspheres in the dynamic environment resulted in faster rate of degradation. The degradation mechanism follows that of a surface degradation process. Microspheres underwent reduction in size and weight loss upon release of Ca2+ ions into Dulbecco’s Phosphate Buffered Saline medium (DPBS). Apatite reprecipitation was visible in the form of granular deposits in both environments from day 1 and continued throughout 21 days which altered the size of the microspheres but not its shape.

Improving the dissolution of lidocaine by dispersing the rapid expansion of supercritical solution

An experimental study of the grinding of lidocaine by the rapid expansion of supercritical solutions (RESS method) was carried out. The experiments were carried out in the pressure range of 10-35 MPa and temperatures of 308-333 K. The analysis of the morphology and size of particles, as well as the effect of the process parameters on them, was carried out. Qualitative and quantitative spectrophotometric analysis was carried out. The dissolution test was carried out in a phosphate buffered saline medium simulating plasma, which showed that the reduction in particle size gave an increased yield of the drug in a shorter period of time compared to the original drug that was not treated. Keywords: supercritical fluid, microparticles, spectrophotometric analysis, lidocaine.

Synthesis and characterization of cellulose-based graft copolymers crosslinked by gamma-irradiation for enhanced oil recovery applications

Cellulose-based polymers have garnered significant attention as potential candidates for use in enhanced oil recovery (EOR). The challenge in the design of EOR polymers is the need for materials with a high low critical solution temperature (LCST) and the ability to withstand harsh environmental conditions. In this study, cellulose-methylcellulose graft copolymers were prepared with different cellulose to methylcellulose weight ratios. The copolymerization was carried out using gamma radiation doses of 5, 15, and 25 kGy, respectively. The LCST of the copolymers were evaluated using differential scanning calorimetry analysis. The effect of salt addition on the LCST of the materials was studied using different phosphate-buffered saline (PBS) concentrations. The results showed that the cellulose monomer concentration increase from 0.1 to 0.5% in 2% methylcellulose dispersed in water reduced the LCST from 59 to 54°C. The hydrophobic nature of cellulose moieties induced the aggregation of the copolymers into core-shell micelles. Besides, higher gamma radiation doses lowered the LCST of the copolymers. The increase in the salt concentration in the PBS medium tended to decrease the LCST due to disrupted hydration structure of the polymer chains. This work revealed that cellulose-methylcellulose copolymers could be used in chemical EOR due to their high phase transition temperatures, preventing pore clogging and enhancing oil production in the producing wells.

Environmentally-friendly preparation of chitosan microspheres and encapsulation studies of cinnamaldehyde: Тowards convenient sustained release system for cinnamaldehyde

Chitosan, a biodegradable and biocompatible polysaccharide, is a biopolymer with high potential for biomedical applications. In the scope of this study, chitosan microcapsules were prepared via a green method, without using any surfactants or crosslinkers. Cinnamaldehyde encapsulated microspheres were obtained by the same method and characterized by FTIR spectroscopy, XRD spectroscopy, and SEM. The release study of encapsulated cinnamaldehyde was carried out in a pH 7.4 phosphate buffered saline (PBS) at 37 °C. The amount of cinnamaldehyde released was analyzed using UV-Vis spectroscopy and GC/MS-MS. Accordingly, it was found that 350 mg of cinnamaldehyde was encapsulated per gram of chitosan, and the maximum amount of cinnamaldehyde released into the PBS medium was about 8 ppm. In addition, the release was seen to continue when the buffer was renewed. It is thought that the obtained cinnamaldehyde encapsulated chitosan microspheres could be used as a sustained release system.

Analysis by real-time PCR of five transport and conservation mediums of nasopharyngeal swab samples to COVID-19 diagnosis in Santiago of Chile.

Due to the COVID‐19 pandemic, many transport kits have been manufactured to preserve and transport nasopharyngeal swab samples (NPSs) from patients. However, there is no information on the performance of the different virus transport media (VTM) used in COVID‐19 diagnosis in the population of Santiago de Chile. We compared the RT‐qPCR amplification profile of five different viral transport kit mediums, including DNA/RNA Shield™, NAT, VTM‐N, Ezmedlab™, and phosphate‐buffered saline (PBS), for NPSs from Central Metropolitan Health Service, Santiago, Chile. The DNA/RNA Shield™ medium showed a better performance in terms of Cq and RFU values for the internal reference RNase P and viral ORF1ab probes. By contrast, the PBS transport medium registered higher Cq values for the viral and reference gene, compared to the other VTM. DNA/RNA Shield™ shows higher relative fluorescence units (RFUs) and lower Cq values for the reference gene. Collectively, our results suggest that the PBS medium could compromise the sample diagnosis because of its lower RT‐qPCR performance. The NAT, Ezmedlab and VTM‐N, and DNA/RNA Shield™ media show acceptable RT‐qPCR parameters and, consequently, seem suitable for use in COVID‐19 diagnosis.

Preclinical evaluation of acute systemic toxicity of magnesium incorporated poly(lactic-co-glycolic acid) porous scaffolds by three-dimensional printing.

ABSTRACTBiodegradable polymer scaffolds combined with bioactive components which accelerate osteogenesis and angiogenesis have promise for use in clinical bone defect repair. The preclinical acute toxicity evaluation is an essential assay of implantable biomaterials to assess the biosafety for accelerating clinical translation. We have successfully developed magnesium (Mg) particles and beta-tricalcium phosphate (β-TCP) for incorporation into poly(lactic-co-glycolic acid) (PLGA) porous composite scaffolds (PTM) using low-temperature rapid prototyping three-dimensional-printing technology. The PTM scaffolds have been fully evaluated and found to exhibit excellent osteogenic capacity for bone defect repair. The preclinical evaluation of acute systemic toxicities is essential and important for development of porous scaffolds to facilitate their clinical translation. In this study, acute systemic toxicity of the PTM scaffolds was evaluated in mice by intraperitoneal injection of the extract solutions of the scaffolds. PTM composite scaffolds with different Mg and β-TCP content (denoted as PT5M, PT10M, and PT15M) were extracted with different tissue culture media, including normal saline, phosphate-buffered saline , and serum-free minimum essential medium , to create the extract solutions. The evaluation was carried out following the National Standard. The acute toxicity was fully evaluated through the collection of extensive data, including serum/organs ion concentration, fluorescence staining, and in vivo median lethal dose measurement. Mg in major organs (heart, liver, and lung), and Mg ion concentrations in serum of mice, after intraperitoneal injection of the extract solutions, were measured and showed that the extract solutions of PT15M caused significant elevation of serum Mg ion concentrations, which exceeded the safety threshold and led to the death of the mice. In contrast, the extract solutions of PT5M and PT10M scaffolds did not cause the death of the injected mice. The median lethal dose of Mg ions in vivo for mice was determined for the first time in this study to be 110.66 mg/kg, and the safety level of serum magnesium toxicity in mice is 5.4 mM, while the calcium serum safety level is determined as 3.4 mM. The study was approved by the Animal Care and Use Committee of Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences (approval No. SIAT-IRB-170401-YGS-LYX-A0346) on April 5, 2017. All these results showed that the Mg ion concentration of intraperitoneally-injected extract solutions was a determinant of mouse survival, and a high Mg ion concentration (more than 240 mM) was the pivotal factor contributing to the death of the mice, while changes in pH value showed a negligible effect. The comprehensive acute systemic toxicity evaluation for PTM porous composite scaffolds in this study provided a reference to guide the design and optimization of this composite scaffold and the results demonstrated the preclinical safety of the as-fabricated PTM scaffold with appropriate Mg content, strongly supporting the official registration process of the PTM scaffold as a medical device for clinical translation.

Lipid Coating of Chitosan Nanogels for Improved Colloidal Stability and In Vitro Biocompatibility.

Chitosan-based carriers have coined their position as delivery agents. When assembled with polyanions into nanogels (NG), these vectors have enabled the delivery of drugs, genes, and proteins to a myriad of applications. However, the chemical and colloidal instability of chitosan nanoformulations in physiologically compatible media prejudices in vitro biocompatibility and, thus, scale-up applications. To overcome this issue, we envisaged the coating of chitosan nanogel with phospholipids. In this investigation, we report a two-stage synthesis of hybrid lipid-coated chitosan nanogels, named nanolipogels (NLG), to improve colloidal stability and in vitro biocompatibility over chitosan NG. Practically, we employed a mixing platform to first prepare chitosan NG by ionic gelation, dilute the suspension, and, in a second stage, coat the NG with lipids. We demonstrate that lipid coating increased particle size and reversed the ζ-potential to negative values, suggesting the successful formation of NLG, while maintaining a homogeneous size distribution (PDI < 0.25). Furthermore, multiple light scattering analysis confirmed NLG improved colloidal stability in phosphate buffer saline and cell culture medium, with respect to NG. Finally, lipid coating completely abrogated the cytotoxicity of NG when incubated at 50 μg·mL-1 with HeLa, U87, or b.End3 cell lines and significantly improved the biocompatibility at 100 and 150 μg·mL-1. Future investigations will explore how the lipid coating affects drug loading, release profile, and the ability of NLG to deliver drugs and genes in vitro.

On the importance of physical and mechanical properties of PLGA films during drug release

Physical and mechanical properties of the drug-incorporated polymer play a significant role in the release behavior from the drug carriers. Understanding the relative extent of variation in the physical and mechanical properties of the polymer makes it possible to improve the design of polymer carriers to obtain better release profile and increase drug stability. Drug delivery from PLGA loaded with various percentages of diclofenac sodium (DS: 0, 5%, and 10%) at different flow rates of 0 and 7.5 ml/s (flow rate of the healthy internal carotid artery) in phosphate buffered saline (PBS) for different release intervals has been studied. In this research, the change of some physical properties such as free volume fraction, glass transition temperature (Tg) and mechanical properties before and during PLGA release have been investigated. In-vitro release tests have been performed in the PBS medium at the temperature of 37 °C. The results showed that during drug release, Youngs’ modulus and ultimate stress were increased while elongation at break was decreased for different drug loaded films and flow rates. In addition, the zero order kinetic model was found to best fit all the release-profiles obtained.

Улучшение растворения лидокаина посредством диспергирования методом быстрого расширения сверхкритического раствора

An experimental study of the grinding of lidocaine by the rapid expansion of supercritical solutions (RESS method) was carried out. The experiments were carried out in the pressure range of 10–35 MPa and temperatures of 308–333 K. The analysis of the morphology and size of particles, as well as the effect of the process parameters on them, was carried out. Qualitative and quantitative spectrophotometric analysis was carried out. The dissolution test was carried out in a phosphate buffered saline medium simulating plasma, which showed that the reduction in particle size gave an increased yield of the drug in a shorter period of time compared to the original drug that was not treated.

Surface Functionalization of Three Dimensional-Printed Polycaprolactone-Bioactive Glass Scaffolds by Grafting GelMA Under UV Irradiation

In this study, bioactive glass nanoparticles (BGNPs) with an average diameter of less than 10 nm were synthesized using a sol-gel method and then characterized by transmission electron microscopy (TEM), differential scanning calorimetric (DSC), Fourier transforms infrared spectroscopy (FTIR), and x-ray spectroscopy (XRD). Afterward, three dimensional (3D)-printed polycaprolactone (PCL) scaffolds along with fused deposition modeling (FDM) were incorporated with BGNPs, and the surface of the composite constructs was then functionalized by coating with the gelatin methacryloyl (GelMA) under UV irradiation. Field emission scanning electron microscopy micrographs demonstrated the interconnected porous microstructure with an average pore diameter of 260 µm and homogeneous distribution of BGNPs. Therefore, no noticeable shrinkage was observed in 3D-printed scaffolds compared with the computer-designed file. Besides, the surface was uniformly covered by GelMA, and no effect of surface modification was observed on the microstructure while surface roughness increased. The addition of the BGNPs the to PCL scaffolds showed a slight change in pore size and porosity; however, it increased surface roughness. According to mechanical analysis, the compression strength of the scaffolds was increased by the BGNPs addition and surface modification. Also, a reduction was observed in the absorption capacity and biodegradation of scaffolds in phosphate-buffered saline media after the incorporation of BGNPs, while the presence of the GelMA layer increased the swelling potential and stability of the composite matrixes. Moreover, the capability of inducing bio-mineralization of hydroxyapatite-like layers, as a function of BGNPs content, was proven by FE-SEM micrographs, EDX spectra, and x-ray diffraction spectra (XRD) after soaking the obtained samples in concentrated simulated body fluid. A higher potential of the modified constructs to interact with the aqueous media led to better precipitation of minerals. According to in-vitro assays, the modified scaffolds can provide a suitable surface for the attachment and spreading of the bone marrow mesenchymal stem cells (BMSCs). Furthermore, the number of the proliferated cells confirms the biocompatibility of the scaffolds, especially after a modification process. Cell differentiation was verified by alkaline phosphatase activity as well as the expression of osteogenic genes such as osteocalcin and osteopontin. Accordingly, the scaffolds showed an initial potential for reconstruction of the injured bone.

Synthesis, Biological, and Computational Evaluation of Antagonistic, Chiral Hydrobenzoin Esters of Arecaidine Targeting mAChR M1

Muscarinic acetylcholine receptors (mAChRs) are a pivotal constituent of the central and peripheral nervous system. Yet, therapeutic and diagnostic applications thereof are hampered by the lack of subtype selective ligands. Within this work, we synthesized and chemically characterized three different stereoisomers of hydrobenzoin esters of arecaidine by NMR, HR-MS, chiral chromatography, and HPLC-logP. All compounds are structurally eligible for carbon-11 labeling and show appropriate stability in Dulbecco’s phosphate-buffered saline (DPBS) and F12 cell culture medium. A competitive radioligand binding assay on Chinese hamster ovary cell membranes comprising the human mAChR subtypes M1-M5 showed the highest orthosteric binding affinity for subtype M1 and a strong influence of stereochemistry on binding affinity, which corresponds to in silico molecular docking experiments. Ki values toward M1 were determined as 99 ± 19 nM, 800 ± 200 nM, and 380 ± 90 nM for the (R,R)-, (S,S)-, and racemic (R,S)-stereoisomer, respectively, highlighting the importance of stereochemical variations in mAChR ligand development. All three stereoisomers were shown to act as antagonists toward mAChR M1 using a Fluo-4 calcium efflux assay. With respect to future positron emission tomography (PET) tracer development, the (R,R)-isomer appears especially promising as a lead structure due to its highest subtype selectivity and lowest Ki value.