Preparation of Gelatin-Quaternary Ammonium Salt Coating on Titanium Surface for Antibacterial/Osteogenic Properties.

Titanium (Ti) and its alloys are widely used in medical treatment, engineering, and other fields because of their excellent properties including biological activity, an elastic modulus similar to that of human bones, and corrosion resistance. However, there are still many defects in the surface properties of Ti in practical applications. For example, the biocompatibility of Ti with bone tissue can be greatly reduced in implants due to a lack of osseointegration as well as antibacterial properties, which may lead to osseointegration failure. To address these problems and to take advantage of the amphoteric polyelectrolyte properties of gelatin, a thin layer of gelatin was prepared by electrostatic self-assembly technology. Diepoxide quaternary ammonium salt (DEQAS) and maleopimaric acid quaternary ammonium salt (MPA-N+) were then synthesized and grafted onto the thin layer. The cell adhesion and migration experiments demonstrated that the coating has excellent biocompatibility, and those grafted with MPA-N+ promoted cell migration. The bacteriostatic experiment showed that the mixed grafting with two ammonium salts had excellent bacteriostatic performance against Escherichia coli and Staphylococcus aureus, with bacteriostasis rates of 98.1 ± 1.0% and 99.2 ± 0.5%, respectively.

Biomimetic and Multifunctional Hemostatic Hydrogel with Rapid Thermoresponsive Gelation and Robust Wet Adhesion for Emergency Hemostasis: A Rational Design Based on Photo-Cross-Linking Coordinated Hydrophilic-Hydrophobic Balance Strategies.

Uncontrolled bleeding in emergency situations is a great threat to both military and civilian lives, and an ideal hemostat for effectively controlling prehospital hemorrhage is urgently needed but still lacking. Although hemostatic hydrogels are promising for emergency hemostasis, they are currently challenged by either the mutual exclusion between a short gelation time and strong adhesive network or the insufficient functionality of ingredients and complicated operations for in situ curing. Herein, an extracellular matrix biopolymer-based and multifunctional hemostatic hydrogel that simultaneously integrates rapid thermoresponsive gelation, robust wet adhesion, and ease of use in emergencies is rationally engineered. This hydrogel can be conveniently used via simple injection and achieves instant sol-gel phase transition at body temperature. Its comprehensive performance could be facilely regulated by tuning the proportions of components, and the optimal performance (gelation time 6-8 s, adhesion strength 125 ± 3.6 kPa, burst pressure 282 ± 4.1 mmHg) is established due to the coordinated enhancement of the photo-cross-linking pretreatment and the hydrophilic-hydrophobic balance among various interactions in the hydrogel system. Additionally, it exhibits significant coagulation effect in vitro and enables effective hemostasis and wound healing in vivo. This work provides a promising platform for versatile applications of hydrogel-based materials, including emergency hemostasis.

Influence of a Composite Polylysine-Polydopamine-Quaternary Ammonium Salt Coating on Titanium on Its Ostogenic and Antibacterial Performance.

Thin oxide layers form easily on the surfaces of titanium (Ti) components, with thicknesses of <100 nm. These layers have excellent corrosion resistance and good biocompatibility. Ti is susceptible to bacterial development on its surface when used as an implant material, which reduces the biocompatibility between the implant and the bone tissue, resulting in reduced osseointegration. In the present study, Ti specimens were surface-negatively ionized using a hot alkali activation method, after which polylysine and polydopamine layers were deposited on them using a layer-by-layer self-assembly method, then a quaternary ammonium salt (QAS) (EPTAC, DEQAS, MPA-N+) was grafted onto the surface of the coating. In all, 17 such composite coatings were prepared. Against Escherichia coli and Staphylococcus aureus, the bacteriostatic rates of the coated specimens were 97.6 ± 2.0% and 98.4 ± 1.0%, respectively. Thus, this composite coating has the potential to increase the osseointegration and antibacterial performance of implantable Ti devices.

Intra-individual heteroplasmy in the Gentiana tongolensis plastid genome (Gentianaceae).

Chloroplasts are typically inherited from the female parent and are haploid in most angiosperms, but rare intra-individual heteroplasmy in plastid genomes has been reported in plants. Here, we report an example of plastome heteroplasmy and its characteristics in Gentiana tongolensis (Gentianaceae). The plastid genome of G. tongolensis is 145,757 bp in size and is missing parts of petD gene when compared with other Gentiana species. A total of 112 single nucleotide polymorphisms (SNPs) and 31 indels with frequencies of more than 2% were detected in the plastid genome, and most were located in protein coding regions. Most sites with SNP frequencies of more than 10% were located in six genes in the LSC region. After verification via cloning and Sanger sequencing at three loci, heteroplasmy was identified in different individuals. The cause of heteroplasmy at the nucleotide level in plastome of G. tongolensis is unclear from the present data, although biparental plastid inheritance and transfer of plastid DNA seem to be most likely. This study implies that botanists should reconsider the heredity and evolution of chloroplasts and be cautious with using chloroplasts as genetic markers, especially in Gentiana.