Determining the conformation of an adsorbed Br-PEG-peptide by long period X-ray standing wave fluorescence

Fabrication of a three-dimensional printed gelatin/sodium alginate/nano-attapulgite composite polymer scaffold loaded with leonurine hydrochloride and its effects on osteogenesis and vascularization

Bone tissue engineering scaffolds have made significant progress in treating bone defects in recent decades. However, the lack of a vascular network within the scaffold limits bone formation after implantation in vivo. Recent research suggests that leonurine hydrochloride (LH) can promote healing in full-thickness cutaneous wounds by increasing vessel formation and collagen deposition. Gelatin and Sodium Alginate are both polymers. ATP is a magnesium silicate chain mineral. In this study, a Gelatin/Sodium Alginate/Nano-Attapulgite composite hydrogel was used as the base material first, and the Gelatin/Sodium Alginate/Nano-Attapulgite composite polymer scaffold loaded with LH was then created using 3D printing technology. Finally, LH was grafted onto the base material by an amide reaction to construct a scaffold loaded with LH to achieve long-term LH release. When compared to pure polymer scaffolds, in vitro results showed that LH-loaded scaffolds promoted the differentiation of BMSCs into osteoblasts, as evidenced by increased expression of osteogenic key genes. The results of in vivo tissue staining revealed that the drug-loaded scaffold promoted both angiogenesis and bone formation. Collectively, these findings suggest that LH-loaded Gelatin/Sodium Alginate/Nano-Attapulgite composite hydrogel scaffolds are a potential therapeutic strategy and can assist bone regeneration.

Brominated tyrosine and polyelectrolyte multilayer analysis by laser desorption vacuum ultraviolet postionization and secondary ion mass spectrometry

The small molecular analyte 3,5-dibromotyrosine (Br(2)Y) and chitosan-alginate polyelectrolyte multilayers (PEM) with and without adsorbed Br(2)Y were analyzed by laser desorption postionization-mass spectrometry (LDPI-MS). LDPI-MS using a 7.87 eV laser and tunable 8-12.5 eV synchrotron vacuum ultraviolet (VUV) radiation found that desorption of clusters from Br(2)Y films allowed detection by ≤8 eV single photon ionization. Thermal desorption and electronic structure calculations determined the ionization energy of Br(2)Y to be ~8.3 ± 0.1 eV and further indicated that the lower ionization energies of clusters permitted their detection at ≤8 eV photon energies. However, single photon ionization could only detect Br(2)Y adsorbed within PEMs when using either higher photon energies or matrix addition to the sample. All samples were also analyzed by 25 keV Bi(3)(+) secondary ion mass spectrometry (SIMS), with the negative ion spectra showing strong parent ion signal which complemented that observed by LDPI-MS. However, the negative ion SIMS appeared strongly dependent on the high electron affinity of this specific analyte and the analyte's condensed phase environment.