Mesenchymal stem cells aligned and stretched in self-assembling peptide hydrogels.

The presented research highlights a novel approach using fmoc-protected peptide hydrogels for the encapsulation and stretching of mesenchymal stem cells (MSCs). This study utilized a custom mechanical stretching device with a PDMS chamber to stretch human MSCs encapsulated in Fmoc hydrogels. The study assessed the influence of various solvents on the self-assembly and mechanical properties of the hydrogels, and MSC viability and alignment. Particularly we focused on fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) prepared in dimethyl sulfoxide (DMSO), hexafluoro-2-propanol (HFP), and deionized water (DiH2O). Through molecular self-assembly of the peptide sequence into ß-sheets connected by π-π aromatic stacking of F-F groups, the peptide hydrogel was found to form a stiff, hydrated gel with nanofiber morphology and a compressive modulus ranging from 174 to 277 Pa. Therefore, this hydrogel can mimic certain critical features of the extracellular matrix and collagen. Evaluations of MSCs cultured on the peptide hydrogels, including viability, morphology, and alignment assessments using various staining techniques, demonstrated that 3D-cultured MSCs in Fmoc-FF/HFP and Fmoc-FF/DMSO, followed by mechanical stretching, exhibited elongated morphology with distinct microfilament fibers compared to the control cells, which maintained a round and spherical F-actin shape. Notably, peptide gels with a concentration of 5 mM maintained 100 % MSC viability. The findings indicate the potential and specific conditions for successful cell encapsulation and alignment within peptide hydrogels, highlighting a promising tissue engineering platform through the encapsulation of MSCs in peptide nanofibers followed by a stretching process. By enhancing our understanding of MSC-peptide hydrogel interactions, this research contributes to the development of biomaterials tailored for regenerative medicine.

In Vitro Self-Assembly of a Modified Diphenylalanine Peptide to Nanofibers Induced by the Eye Absent Enzyme and Alkaline Phosphatase and Its Activity against Breast Cancer Cell Proliferation.

Drug-resistant breast cancers such as Triple negative breast cancer (TNBC) do not respond successfully to chemotherapy treatments because they lack the expression of receptor targets. Drug-resistant anti-cancer treatments require innovative approaches to target these cells without relying on the receptors. Intracellular self-assembly of small molecules induced by enzymes is a nanotechnology approach for inhibiting cancer cell growth. In this approach, enzymes will induce the self-assembly of small molecules to nanofibers, which leads to cell death. Here, we investigate the self-assembly of a modified small peptide induced by two different phosphatases: alkaline phosphatase (ALP) and eye absent tyrosine phosphatase (EYA). ALPs are expressed in many adult human tissues and are critical for many cellular functions. EYAs are embryonic enzymes that are over-expressed in drug-resistant breast cancers. We synthesized a small diphenylalanine-based peptide with a tyrosine phosphate end group as the substrate of phosphatase enzymes. Peptides were synthesized with solid phase techniques and were characterized by HPLC and MALDI-TOF. To characterize the self-assembly of peptides exposed to enzymes, different techniques were used such as scattering light intensity, microscopes, and phosphate detection kit. We then determined the toxicity effect of the peptide against normal breast cancer cells, MCF-7, and drug-resistant breast cancer cells, MDA-MB-231. The results showed that the EYA enzyme is able to initiate self-assembly at lower peptide concentration with higher self-assembling intensity compared to ALP. A significant decrease in the TNBC cell number was observed even with a low peptide concentration of 60 µM. These results collectively support the exploration of enzyme self-assembly to treat TNBC.

Pulsatile versus non-pulsatile perfusion in coronary artery bypass operation: The comparison of laboratory and clinical outcomes.

INTRODUCTION: The superiority of pulsatile or non-pulsatile perfusion in cardiopulmonary bypass (CPB) regarding morbidity and mortality is still debated. Therefore, we aimed to investigate the effect of different pulse rates in pulsatile perfusion in patients undergoing coronary artery bypass graft (CABG) and compared it with non-pulsatile perfusion. MATERIALS AND METHODS: In this randomized clinical trial, 90 patients who were all candidates for CABG under CPB were enrolled. Patients in groups A and B received pulsatile perfusion with 30 and 70 pulses per minute, and group C received non-pulsatile perfusion. The biochemical and clinical parameters in the ICU were evaluated in the study groups. RESULTS: There was no statistically significant difference between patients' clinical outcomes and kidney and liver function markers (all Ps> 0.05). Mean serum lactate level increased but did not show a statistically significant difference between the study groups (p = 0.8). The mean urine volume at 12 and 24 h after surgery was higher in group A, but there was no statistically significant difference between the three groups during the study period (p = 0.3). No significant difference was found in the length of the ICU stay between the study groups (p = 0.2). CONCLUSION: Our studied parameters demonstrated no significant difference between pulsatile and non-pulsatile and between 30 and 70 pulse rate pulsatile perfusion methods. Our findings support that pulsatile perfusion with different pulse rates has no advantages over non-pulsatile perfusion in selected CABG cases.

Effects of Co-Solvents on Loading and Release Properties of Self- Assembled Di-Peptide Building Blocks, Towards Drug Delivery Applications.

BACKGROUND: Due to their solid-like porous structure, molecular organogel and microcrystal structures have the capabilities of loading drug molecules, encapsulation, and extended release, all considered as essential properties in drug delivery applications. Phases of these structures, however, depend on the solvent used during the gelation process. OBJECTIVE: Understanding the phase transition between organogel and microcrystal structures through adjusting the mixture ratio of different co-solvents. METHODS: Short peptide Diphenylalanine as the gelation building block was used due to its amino acid sequences that can be exactly selected at its molecular levels. Ethanol as a polar solvent was used in combination with four other co-solvents with different polarity levels, namely Xylene, Toluene, Acetone, and Dimethyl Sulfoxide. The morphology of molecular structures of each co-solvent combination at each ratio level was examined as well as the loading and release properties for a non-polar Flufenamic Acid drug. RESULTS: The resultant structure was affected by the polarity of the co-solvents; in particular, in the sample containing 25 µg/ml of the drug, 94% of the drug amount was loaded inside the organogel. By increasing the drug concentration to 50, 75, and 100 µg/ml, the loading capability decreased to 76%, 47%, and 33%, respectively. CONCLUSION: Molecular organogels have excellent capabilities of loading drug molecules, while microcrystal structures have higher release capacity. The findings of this study reveal how to best design a gelation method to obtain maximum loading or release properties for a particular peptide- based drug delivery application.

Effect of Helicobacter pylori Infection on Serum Lipid Profile.

BACKGROUND: Some studies suggest a significant relationship between Helicobacter pylori infection and atherogenesis; but the mechanism of the relationship is almost unknown. The current study aimed at evaluating the relationship between H. pylori infection and serum lipid profile. PATIENTS AND METHODS: The current study was conducted on 2573 patients, from 2008 to 2015. The serum anti-Helicobacter pylori antibody titer and serum lipid profile were assessed in the study population; data were statistically analyzed by SPSS version 16. P values < 0.05 were considered significant. RESULTS: In the current study, 66.5% of the cases were serologically positive for H. pylori. Among male cases, the level of low density lipoprotein (LDL) was higher in patients with H. pylori infection, compared with that of the ones without the infection (P = 0.03); although level of triglyceride (TG) was higher and the level of high density lipoprotein (HDL) was lower in the cases with H. pylori infection; there was no statistically significant difference between the cases with and without H. pylori infection regarding the level of HDL and TG. Among female cases, the level of TG was significantly lower in patients with H. pylori infection, compared with that of the ones without the infection (P = 0.001); but there was no significant difference between the cases with and without H. pylori infection regarding the level of LDL and HDL. The mean fasting blood sugar (FBS) in the cases with H. pylori infection was significantly higher than that of the ones without the infection (P = 0.04). CONCLUSION: According to the results of the current study, the levels of LDL and FBS were high among the male cases with H. pylori infection. However, in females with H. pylori infection the level of TG was low; hence, it seems that the atherogenicity of H. pylori affected the level of blood sugar more.

Diphenylalanine peptide nanotubes self-assembled on functionalized metal surfaces for potential application in drug-eluting stent.

This study focuses on the potential of diphenylalanine self-assembled peptide nanotubes (FF Nts) for delivery of flufenamic acid (FA) from metal implants. Self-assembly of FF Nts was studied in solution and on surfaces of glass, silicone and gold substrates. FA was loaded inside the shell of FF Nts and subsequently FF/FA Nts were attached to gold surfaces. The substrate were characterized by Field Emission Scanning Electron Microscopy (FESEM), fluorescence microscopy, confocal microscopy, and UV-vis spectroscopy. Release of FA from FF Nts were investigated by immersing coated metal substrates in phosphate-buffered saline for 12 days. Self-assembly of FF in water and solvent resulted in formation of nanotubes, which efficiently loaded 98% of FA with concentration of 20 µg/mL. FESEM images confirmed successful attachment of FF/FA Nts to functionalized gold substrates. In vitro release studies indicated using FF Nts has prolonged the release rate of FA for several days. Biocompatibility studied confirmed more than 50% of the cells were alive in concentration of 250-1000 µg/mL of FF Nts thus suggesting the potential of peptide based self-assemble nanostructures as an alternate system for polymer coating in drugs eluting stents. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2280-2290, 2016.

Self-assembled peptide-based nanostructures: Smart nanomaterials toward targeted drug delivery.

Self-assembly of peptides can yield an array of well-defined nanostructures that are highly attractive nanomaterials for many biomedical applications such as drug delivery. Some of the advantages of self-assembled peptide nanostructures over other delivery platforms include their chemical diversity, biocompatibility, high loading capacity for both hydrophobic and hydrophilic drugs, and their ability to target molecular recognition sites. Furthermore, these self-assembled nanostructures could be designed with novel peptide motifs, making them stimuli-responsive and achieving triggered drug delivery at disease sites. The goal of this work is to present a comprehensive review of the most recent studies on self-assembled peptides with a focus on their "smart" activity for formation of targeted and responsive drug-delivery carriers.

Electrospinning of Cross-Linked Magnetic Chitosan Nanofibers for Protein Release.

A poly(vinylalcohol) (PVA) electrospun/magnetic/chitosan nanocomposite fibrous cross-linked network was fabricated using in situ cross-linking electrospinning technique and used for bovine serum albumin (BSA) loading and release applications. Sodium tripolyphosphate (TPP) and glutaraldehyde (GA) were used as cross-linkers which modified magnetic-Fe3O4 chitosan as Fe3O4/CS/TPP and Fe3O4/CS/GA, respectively. BSA was used as a model protein drugs which was encapsulated to form Fe3O4/CS/TPP/BSA and Fe3O4/CS/GA/BSA nanoparticles. The composites were electrospun with PVA to form nanofibers. Nanofibers were characterized by field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). The characterization results suggest that Fe3O4 nanoparticles with average size of 45 nm were successfully bound on the surface of chitosan. The cross-linked nanofibers were found to contain uniformly dispersed Fe3O4 nanoparticles. The size and morphology of the nanofibers network was controlled by varying the cross-linker type. FTIR data show that these two polymers have intermolecular interactions. The sample with TPP cross-linker showed an enhancement of the controlled release properties of BSA during 30-h experimental investigation. Graphical Abstract ᅟ.

Supercritical CO2 generation of nanometric structure from Ocimum basilicum mucilage prepared for pharmaceutical applications.

Plant-derived polymers are widely used in the pharmaceutical industry due to their emollient, lack of toxicity, and irritating nature and low cost. In this work, basil seed mucilage was dried using supercritical carbon dioxide phase inversion technique to form a nanometric structure. The obtained polymeric structures were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method, and Fourier transform infrared spectroscopy (FTIR) and compared with the oven-derived sample group. It was demonstrated that the product morphology could be controlled by altering the composition of methanol which functioned as the co-solvent in the nonsolvent stream. The most homogeneous product (60-nm mean pore size diameter, 78 m(2)/g BET surface area with no agglomeration) was obtained with 2.5% methanol. The FTIR data showed that the presence of hydroxyl and carboxyl groups suggested the bioadhesive property of basil seed mucilage was good and many active pharmaceutical compounds might be loaded to the resultant nanometric structure to enhance drug release. Furthermore, the FTIR analyses indicated that the nature of the final product did not change during the supercritical drying procedure.

Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis.

The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the NCH3 functional group about 2850cm(-1) is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field.

Preparation of biocompatible magnetite-carboxymethyl cellulose nanocomposite: characterization of nanocomposite by FTIR, XRD, FESEM and TEM.

The preparation and characterization of magnetite-carboxymethyl cellulose nano-composite (M-CMC) material is described. Magnetite nano-particles were synthesized by a modified co-precipitation method using ferrous chloride tetrahydrate and ferric chloride hexahydrate in ammonium hydroxide solution. The M-CMC nano-composite particles were synthesized by embedding the magnetite nanoparticles inside carboxymethyl cellulose (CMC) using a freshly prepared mixture of Fe3O4 with CMC precursor. Morphology, particle size, and structural properties of magnetite-carboxymethyl cellulose nano-composite was accomplished using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. As a result, magnetite nano-particles with an average size of 35nm were obtained. The biocompatible Fe3O4-carboxymethyl cellulose nano-composite particles obtained from the natural CMC polymers have a potential range of application in biomedical field.

Immobilization of bacterial S-layer proteins from Caulobacter crescentus on iron oxide-based nanocomposite: synthesis and spectroscopic characterization of zincite-coated Fe2O3 nanoparticles.

Zinc oxide was coated on Fe2O3 nanoparticles using sol-gel spin-coating. Caulobacter crescentus have a crystalline surface layer (S-layer), which consist of one protein or glycoprotein species. The immobilization of bacterial S-layers obtained from C. crescentus on zincite-coated nanoparticles of iron oxide was investigated. The SDS PAGE results of S-layers isolated from C. crescentus showed the weight of 50 KDa. Nanoparticles of the Fe2O3 and zinc oxide were synthesized by a sol-gel technique. Fe2O3 nanoparticles with an average size of 50 nm were successfully prepared by the proper deposition of zinc oxide onto iron oxide nanoparticles surface annealed at 450 °C. The samples were characterized by field-emission scanning electron microscope (FESEM), atomic force microscopy (AFM), powder X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR).

Functionalized biocompatible polyelectrolyte multilayers for drug delivery: in situ investigation of mechanical properties by dissipative quartz crystal microbalance.

Nanostructured polymeric capsules have been applied in different fields, and specifically are regarded as promising for smart drug delivery applications. The physical-chemical and mechanical properties, and thus the permeability of the polyelectrolyte multilayer shell, play an important role in efficient delivery. Quartz crystal microbalance working in liquid has been used for the characterization of the buildup process and of the viscoelastic properties of biocompatible multilayers and of their functionalization by S-layer proteins. Optical and scanning electron microscopy have been used for the morphological characterization of nanostructured capsules obtained at physiological conditions by the assembly of the characterized multilayers onto spherical cores and by their subsequent removal. The proposed functionalized biocompatible capsules can be regarded as promising candidates for smart drug delivery applications.

Polyelectrolyte based molecular carriers: the role of self-assembled proteins in permeability properties.

Polyelectrolyte capsules are seen as promising nanotechnology based drug delivery systems. In previous works, we have demonstrated the possibility to fabricate bio-activated surface layer containing capsules with improved features in terms of biocompatibility. In this study, we have characterized the permeability properties of such capsules towards low and high molecular weight molecules, including proteins. The results indicated that the presence of the surface layer strongly affects the permeability properties of the capsules in terms of loading capacity which was found to be higher compared to that of plain capsules. These properties make such systems interesting candidates as drug delivery platforms.

Nanoengineered polymeric S-layers based capsules with targeting activity.

Nanostructured polymeric capsules are regarded as highly promising systems with different potential applications ranging from drug delivery, biosensing and artificial cells. To fully exploit this potential, it is required to produce bio-activated stable and biocompatible capsules. To this purpose, in present work we proposed the combination of the layer-by-layer self assembly method with bacterial S-layer technology to fabricate stable and biocompatible polymeric capsules having a well defined arrangement of functional groups allowing the covalent attachment of antibody molecules. Hollow microcapsules were obtained by the layer-by-layer self assembly of oppositely charged polyelectrolytes onto colloidal particles, followed by removal of the cores at acidic pH. S-layers were crystallized onto the shell of the obtained capsules. Quartz crystal microbalance was used to characterize the crystallization process onto planar surfaces. S-layer containing capsules were investigated by atomic force microscopy. Immunoenzymatic tests were performed to assess the effective modification of the S-layer with antibody molecules both on planar surfaces and on hollow capsules. Fluorescent microscopy was employed to visualize the presence of the antibody molecules onto the capsule shell and immunological tests used to assess the bioactivity of the immobilized antibodies. Finally, the in vitro cytotoxicity of fabricated S-layer containing capsules was studied. The obtained results demonstrated the possibility to fabricate bio-activated S-layer containing capsules with improved features in terms of biocompatibility.

Development of nanostructured magnetic capsules by means of the layer by layer technique.

Nanomagnetic particles have been already taken into account as drug carriers thank to the possibility to control their movement to a specific location where the treatment is required by means of high gradient magnetic fields (HGMF). In this work the layer-by-layer technique (LbL) and nanomagnetic particles were used to developed innovative nanostructured magnetic capsules (NSMC). Their potential application as magnetic drug carriers was investigated under the influence of both static and oscillating magnetic fields used respectively to control capsule displacement and shell permeability. The assembly process of the nanostructured magnetic capsules, its characterization by Quartz Crystal Microbalance (QCM), and the results obtained under the influence of the magnetic fields are presented.

Self-assembly and recrystallization of bacterial S-layer proteins of Bacillus sphaericus and Bacillus thuringiensis on silicone, mica and quartz crystal supports.

The Oriented architecture of macromolecules plays a critical role in many aspects of Nanobiotechnology such as in the development of biosensors. To this regard, S-layers which constitute the outermost cell envelope component of many prokaryotic organisms, represent unique self assembled systems with the capability to rearrange into monomolecular and oriented arrays. These properties can be exploited to promote their crystallization on surfaces (e.g. silicone) which is pivotal for the subsequent immobilization of macromolecules and development of new biosensors. In this work the crystallization of bacterial S-layers obtained from Bacillus thuringiensis and Bacillus sphaericus CCM2177 on silicone, mica and quartz crystal surfaces were investigated. The SDS page results of S-layers isolated from the above mentioned bacteria put in evidence that their molecular weight (MW) was around 120 KDa and, as reported in the literature, slightly higher for those extracted by Bacillus thuringiensis. In addition, results showed that S-layers isolated from Bacillus thuringiensis form large crystalline domains on mica after 5 min whereas those extracted from Bacillus sphaericus CCM 2177 form a compact monolayer on silicone after 2 h. Results in this work put in evidence the possibility to use these substrates for the fabrication of sensitive biosensors.