In the current study, poly lactic acid (PLA) modified hollow crosslinked poly(hydroxyethyl methacrylate) (PHEMA) microspheres have been prepared.
In the current study, poly lactic acid (PLA) modified ...hollow crosslinked poly(hydroxyethyl methacrylate) (PHEMA) microspheres have been prepared, in order to obtain a stimulus-responsive, biocompatible carrier with sustained drug release properties. The synthetical process consisted of the preparation of poly(methacrylic acid)@poly(hydroxyethyl methacrylate-co-N,N′-methylene bis(acrylamide)) microspheres by a two stage distillation-precipitation polymerization technique using 2,2′-azobisisobutyronitrile as initiator. Following core removal, a PLA coating of the microspheres was formed, after ring opening polymerization of dl-lactide, attributing the initiator's role to the active hydroxyl groups of PHEMA. The anticancer drug daunorubicin (DNR) was selected for the study of loading and release behavior of the coated microspheres. The loading capacity of the PLA modified microspheres was found to be four times higher than that of the parent ones (16% compared to 4%). This coated microspherical carrier exhibited a moderate pH responsive drug release behavior due to the pH dependent water uptake of PHEMA, and PLA hydrolysis. The in vitro cytotoxicity of both the parent and the DNR-loaded or empty modified hollow microspheres has been also examined on MCF-7 breast cancer cells. The results showed that although the empty microspheres were moderately cytotoxic, the DNR-loaded microspheres had more potent anti-tumor effect than the free drug. Therefore, the prepared coated microspheres are interesting drug delivery systems.
The design and fabrication of hollow polymer microspheres responsive to various stimuli comprises a promising approach for the development of multifunctional and efficient systems for various ...nanomedicine-related applications. In this paper, we present the preparation of poly(methacrylic acid-co-N,N′-methylenebis(acrylamide)-co-poly(ethylene glycol) methyl ether methacrylate-co-N,N′-bis(acryloyl)cystamine) (PMAAS–S) hollow microspheres following a two-stage distillation precipitation polymerization procedure. Magnetic and silver nanocrystals were chemically grown on the surface of the hollow polymer microspheres, resulting in a composite system with interesting properties. We evaluated the performance of the composite hollow microspheres as magnetic hyperthermia mediators and their surface-enhanced Raman spectroscopy activity. Assessment of Daunorubicin-loaded PMAAS–S hollow microspheres performance as effective drug carriers was carried out through drug release experiments upon application of different pH and reducing conditions. pH and redox responsiveness as well as basic mechanisms of release profiles are discussed. Furthermore, in vitro cytotoxicity of empty and drug-loaded PMAAS–S hollow microspheres against MCF-7 cancer cells was investigated in order to evaluate their performance as drug carriers.
Amphiphilic block copolymers are well established as building blocks for the preparation of micellar drug carriers. The functional polymer micelles possess several advantages, such as high drug ...efficiency, targeted delivery, and minimized cytotoxicity. The synthesis of block copolymers using nano-structured templates has emerged as a useful and versatile approach for preparing drug carriers. Here, we report the synthesis of a smart polymeric compound of a diblock PLA-Lys-
b
-PEG copolymer containing doxorubicin. We have synthesized functionalized diblock copolymers, with lysinol, poly(lactide) and monomethoxy poly(ethylene glycol) via thermal ring-opening polymerization and a subsequent six-step substitution reaction. A variety of spectroscopic methods were employed here to verify the product of our synthesis.
1
H-Nuclear magnetic resonance and Fourier transform infrared studies validated the expected synthesis of copolymers. Doxorubicin is chemically loaded into micelles, and the ex vitro release can be evaluated either in weak acidic or in SBF solution by UV–vis spectroscopy. Dynamic light scattering, thermo gravimetric analysis, and size exclusion chromatography have also been used.
Magnetic pH-sensitive microcontainers were produced by a four-step process. The first step involves the synthesis of citrate-modified magnetic nanoparticles via the coprecipitation method. The second ...step consists of the encapsulation of magnetic nanoparticles in non-cross-linked poly(methacrylic acid) (PMAA) microspheres through distillation precipitation polymerization, resulting in a core/shell structure. The third step concerns the formation of a poly(N,N′-methylenebis(acrylamide)-co-mathacrylic acid) (P(MBAAm-co-MAA)) layer on the surface of magnetic PMAA microspheres by second distillation precipitation polymerization in order to produce a trilayer hybrid microsphere. The last step deals with the removal of PMAA layer in ethanol and formation of a stable P(MBAAm-co-MAA) microcontainer with magnetic nanoparticles entrapped inside the formed cavity. This process is simple and leads to the formation of superparamagnetic pH-sensitive microcontainers. The structure and properties of the magnetic microcontainers were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), and dynamic light scattering (DLS) to determine the functionalities of the hybrid structure. The magnetic pH-sensitive microcontainers were loaded with Daunorubicin and tested with respect to release rate at different pH values in order to evaluate their functionality as controlled release system.
Composite materials drive shafts attract particular interest in recent years. Their high strength, light weight and high fatigue and corrosion resistance make them suitable for high specification ...mechanical and marine applications. In the context of the present work, advanced finite element models that simulate the static and dynamic mechanical behaviour of composite drive shafts are combined with optimization algorithms in order to determine the optimum lay-up of a composite shaft according to the desired specifications. The composite shaft is also combined with metallic flanges and the performance of the combined system is also investigated. The created models facilitate the structural design optimization of composite material drive shafts and constitute the basis for the future implementation of the simulation driven digital twins of composite materials drivetrain systems.
•Composite driveshafts have high specific strength, fatigue and corrosion resistance.•Composite driveshafts are fit for high specification power transmission systems.•FEA can accurately simulate the composite materials shafts' mechanical behaviour.•FEA combined with optimization algorithms can determine the shaft's optimum lay-up.•Basis of simulation driven digital twins of composite materials drivetrain systems.
A ternary system of SiO₂–CaO–P₂O₅ hollow nanospheres has been successfully prepared by sol–gel method using polystyrene (PS) nanospheres as template. The inorganic shell was produced using ...tetraorthosilicate (TEOS) as the silica source and tri-calciumphospate as calcium and phosphorus sources, respectively. The positive surface charge of the template and the template/TEOS ratio were the key parameters for the creation of a stable primary inorganic network and the further growth of the shell. The removal of the polymeric core through a thermal treatment procedure created an inner void space with mean diameter 250nm while the outer mean diameter was 330nm.
By using either NH
2-functionalized linear/4-arm star poly(ethylene oxide) or NH
2-TEMPO initiator, the following novel polymer/polypeptide hybrids (macromolecular
chimeras) of poly(ethylene oxide), ...PEO and poly(
N-vinyl pyrrolidone), PNVP, were synthesized: PEO-b-(PBLG or PBLL), PEO-b-PBLL-b-PBLG, 4-arm star copolymer (PEO-b-PBLG)
4, PNVP-b-PBLG-b-PBLL, where PBLG is poly(γ-benzyl-
l-glutamate) and PBLL, poly(
tert-butyloxycarbonyl-
l-lysine). The amino-groups are used for the ring opening polymerization (ROP) of α-amino acid carboxyanhydrides (NCAs), while TEMPO was employed for the polymerization of NVP. Molecular characterization revealed the high molecular weight and compositional homogeneity of the macromolecular
chimeras prepared. The success of the synthesis was based on the recently developed living ROP of NCAs and controlled/living TEMPO polymerization, using high vacuum techniques.
Ultrashort amphiphilic peptides, comprised of concise sequences of seven to four amino acids, display distinctive self-assembling behavior in physiological conditions, forming nanofiber-rich ...hydrogels with remarkably high water content (>99% w/w). The hydrogels are comprised of nanofibers and three-dimensional (3D) matrices mirroring the structure of the extracellular matrix. These hydrogels exhibit biocompatibility, creating a nurturing microenvironment that supports the viability, proliferation, and differentiation of stem cells.With the aim of enhancing the peptide scaffolds through integration with human platelet lysate while preserving the self-assembly process, this study explores the synergistic potential of ultrashort peptides and platelet lysates in guiding stem cell behavior within the hydrogel matrix.
In this investigation, a gelation test was performed to determine the minimum gelation concentration of the developed peptide. Additionally, we assessed cell viability, proliferation, as well as cell-cell and cell-matrix interactions. Through the strategic substitution of specific amino acids in the peptide sequence, we achieved the lowest reported minimum gelation concentration for self-assembling peptides, thereby expanding the range of their potential applications.By substituting specific amino acids in the peptide sequence, we successfully developed a peptide sequence that can form a nanofibrous hydrogel with the lowest documented minimum gelation concentration for self-assembling peptides, consequently broadening the scope of their potential applications. The peptide hydrogel formed a highly porous network of nanofibers with tunable mechanical properties. The 3D peptide culture supported the viability and growth of various cell types, including mesenchymal stromal cells. Additionally, it recapitulated cell-cell and cell-matrix interaction. Notably, the developed 3D culture system was able to support the growth of cells using media without serum supplementation. This attribute allows for the provision of a xeno-free 3D culture system that could be employed for advanced biomedical applications.This innovative framework shows potential in transforming the landscape of stem cell therapies by providing customized and dynamic settings. The integration of ultrashort peptides and platelet lysates in hydrogel design represents a significant stride toward advancing the field of stem cell-based therapies.
Mesenchymal stromal cells (MSCs) are multipotent stem cells with pro-generative capabilities that are currently being explored as a potential cellular therapy in various clinical trials. Current ...culture expansion methods for MSCs involve two-dimensional (2D) culture vessels. However, such culture conditions do not accurately mimic the native conditions where the cells reside in vivo and might significantly impact important cellular characteristics. This study aimed to investigate the effects of 3D culture conditions, using a well-defined biomimicry model, on MSCs isolated from bone marrow (BM-MSCs) and umbilical cord (UC-MSCs), with a particular focus on differences in their inherent potential for clinical use.
In this study, we developed a unique class of tetramer self-assembling peptides that possess an innate ability to self-assemble into stable hydrogel without the need for any harmful crosslinking reagents. The developed hydrogel presents a nanofibrous topography that closely mimics collagen, replicating the native architecture of tissue extracellular matrix (ECM). Both BM- and UC-MSCs were 3D cultured inside the peptide hydrogel, and cell viability, proliferation, and morphology were evaluated and compared to 2D culture. Additionally, whole transcriptome analysis using RNAseq was performed on 3D cultured cells at different time points and compared to 2D cultures. The 3D peptide culture facilitated the viability and growth of BM- and UC-MSCs and effectively replicated cell-cell and cell-extracellular matrix interactions. Whole transcriptome data analysis revealed a unique gene expression profile for MSCs under 3D culture conditions, with distinctive gene expression patterns for extracellular matrix, cell adhesion, cell division, cell cycle, and growth factor expression. Collectively, our data demonstrate the impact of 3D culture on MSCs and its potential to enhance cellular properties in different aspects for improved clinical applications.
A ternary system of SiO
2–CaO–P
2O
5 hollow nanospheres has been successfully prepared by sol–gel method using polystyrene (PS) nanospheres as template. The inorganic shell was produced using ...tetraorthosilicate (TEOS) as the silica source and tri-calciumphospate as calcium and phosphorus sources, respectively. The positive surface charge of the template and the template/TEOS ratio were the key parameters for the creation of a stable primary inorganic network and the further growth of the shell. The removal of the polymeric core through a thermal treatment procedure created an inner void space with mean diameter 250
nm while the outer mean diameter was 330
nm.
► Fine hollow SiO
2-CaO-P
2O
5 nanospheres via core-shell synthesis. ► Structure stability was observed even though the layer was very thin. ► Nanospheres with thinner layer showed transparent at the SEM micrographs.
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