Effects of Culture Substrate Made of Poly(N-isopropylacrylamide-co-acrylic acid) Microgels on Osteogenic Differentiation of Mesenchymal Stem Cells

Molecular dynamics investigation on synthesis of a pH- and temperature-sensitive carbon nanotube loaded with doxorubicin

The many exotic properties of carbon nanotubes (CNTs) make them a powerful attraction in the field of drug delivery systems (DDS). In this work, based on quantum chemical calculation and molecular simulation techniques, polyacrylic acid (PAA) and N-isopropyl acrylamide (NIP) are selected and acted simultaneously on the CNT to form a stable system (FCNT). As a potential DDS, FCNT captures the dispersed doxorubicin (DOX) molecules around it and maintains a stable configuration. In these processes, electrostatic and van der Waals forces act synergistically, with van der Waals forces dominating. Compared to NIP, PAA molecules exhibit stronger adhesion and encapsulation efficiency to CNT and stronger adsorption capacity to DOX. This study reveals the mechanism of action among PAA, NIP, CNT, and DOX, providing feasibility verification and prospective guidance for the experimental synthesis of PAA-NIP-CNT-type multifunctional DDS, and also broadening the idea for exploring more efficient DDS suitable for DOX.

Macrophages at Low-Inflammatory Status Improved Osteogenesis via Autophagy Regulation

Accumulating evidence indicates that the interaction between immune and skeletal systems is vital in bone homeostasis. However, the detailed mechanisms between macrophage polarization and osteogenic differentiation of mesenchymal stromal cells (bone marrow-derived stromal cells [BMSCs]) remain largely unknown. We observed enhanced macrophage infiltration along with bone formation in vivo, which showed a transition from early-stage M1 phenotype to later stage M2 phenotype, cells at the transitional stage expressed both M1 and M2 markers that actively participated in osteogenesis, which was mimicked by stimulating macrophages with lower inflammatory stimulus (compared with typical M1). Using conditioned medium (CM) from M0, typical M1, low-inflammatory M1 (M1semi), and M2 macrophages, it was found that BMSCs treated with M1semi CM showed significantly induced migration, osteogenic differentiation, and mineralization, compared with others. Along with the induced osteogenesis, the autophagy level was the highest in M1semi CM-treated BMSCs, which was responsible for BMSC migration and osteogenic differentiation, as autophagy interruption significantly abolished this effect. This study indicated that low-inflammatory macrophages could activate autophagy in BMSCs to improve osteogenesis.

Molecular dynamics simulation of Doxorubicin loading with N-isopropyl acrylamide carbon nanotube in a drug delivery system

BACKGROUND AND OBJECTIVE

Doxorubicin is one of the common drugs used for cancer therapy. Molecular dynamics were applied to investigate the loading of Doxorubicin with thermosensitive N-isopropyl acrylamide Carbon nanotube carrier.

METHODS

The results showed that the smaller polymer chain length has more decrease of gyration radius. A decrease of gyration radius resulted in more concentrated aggregation with stronger bonds. Therefore, the shorter the polymer chain lengths, the more stable polymer interaction and better Doxorubicin delivery. Smaller polymers also form more hydrogen bonds with the drug leading to stronger and more stable carriers.

RESULTS

A lower amount of wall shear stress was found near the inner wall of the artery, distal to the plaque region (stenosis), and in both percentages of stenosis the maximum wall shear stress will accrue in the middle of the stenosis; however it is much more in the higher rate of stenosis.

CONCLUSIONS

The results indicated that N-isopropyl acrylamide - Carbon nanotube is suitable for the delivery of Doxorubicin, and five mer N-isopropyl acrylamide is the optimum carrier for Doxorubicin loading.

Magnetic solid phase extraction of bisphenol A, phenol and hydroquinone from water samples by magnetic and thermo dual-responsive core-shell nanomaterial

Present study prepared a new magnetic and thermo dual-responsive core-shell nanomaterial (Fe@SiO₂@poly(N-isopropylacrymide-co-methacrylic acid, Fe@SiO₂@PNIPAM-co-MAA), which was characterized by transmission electron microscopy and X-ray diffraction techniques. The new nanomaterials integrated with the magnetism of nanoscale zero valent iron material and thermo-response of the copolymers, and were utilized to investigate the adsorption capacity for typical phenols such as bisphenol A, phenol and hydroquinone from water samples, and the results showed that the magnetic and thermo dual-responsive core-shell nanomaterial exhibited good adsorption ability to typical phenols. Based on these, a sensitive method was developed for the determination of bisphenol A, phenol and hydroquinone using as-prepared magnetic nanoparticles as the magnetic solid phase extraction sorbent prior to high performance liquid chromatography coupled with variable wavelength detection. Under the optimal conditions, linear linearity was obtained over the range of 0.1-500 μg L^-1 with the correlation coefficients (r²) above 0.996. The detection limits of three analytes were in the range of 0.019-0.031 μg L^-1, and the precisions were all less than 4.8% (n = 6). The developed method was evaluated with real water samples and excellent spiked recoveries in the range of 94.0-105.4% were achieved. These results indicated that the proposed method was a robust analytical tool and a useful alternative for routine analysis of such pollutants.

Ultralow Self-Cross-Linked Poly(N-isopropylacrylamide) Microgels Prepared by Solvent Exchange

We found that the poly(N-isopropylacrylamide) (PNIPAm) synthesized by free-radical polymerization in organic phase could also form stable microgels in water through solvent exchange without chemical cross-linkers. Dynamic light scattering and transmission electron microscopy showed the larger swelling ratio and higher deformability of these microgels. Nuclear magnetic resonance and infrared spectroscopy indicated that the self-cross-linking structures in these microgels were attributed to the hydrogen atom abstraction both from the isopropyl tert-carbon atoms and the vinyl tert-carbon atoms in PNIPAm chains and the organic solvents were important assistants in the hydrogen abstraction behavior. Our discovery revealed that the self-cross-linking of PNIPAm chains is a common phenomenon within their free-radical polymerization process, whether in aqueous phase or in organic phase. Besides, the addition of second monomers will not affect the cross-linkage of the PNIPAm portion, which may be of great significance for the synthesis of various functional ultralow cross-linking PNIPAm microgels.

Nanogels and Microgels: From Model Colloids to Applications, Recent Developments, and Future Trends

Nanogels and microgels are soft, deformable, and penetrable objects with an internal gel-like structure that is swollen by the dispersing solvent. Their softness and the potential to respond to external stimuli like temperature, pressure, pH, ionic strength, and different analytes make them interesting as soft model systems in fundamental research as well as for a broad range of applications, in particular in the field of biological applications. Recent tremendous developments in their synthesis open access to systems with complex architectures and compositions allowing for tailoring microgels with specific properties. At the same time state-of-the-art theoretical and simulation approaches offer deeper understanding of the behavior and structure of nano- and microgels under external influences and confinement at interfaces or at high volume fractions. Developments in the experimental analysis of nano- and microgels have become particularly important for structural investigations covering a broad range of length scales relevant to the internal structure, the overall size and shape, and interparticle interactions in concentrated samples. Here we provide an overview of the state-of-the-art, recent developments as well as emerging trends in the field of nano- and microgels. The following aspects build the focus of our discussion: tailoring (multi)functionality through synthesis; the role in biological and biomedical applications; the structure and properties as a model system, e.g., for densely packed arrangements in bulk and at interfaces; as well as the theory and computer simulation.