Substitution of Percutaneous Ethanol Injection with a Low Molecular Weight Peptide Gel Mimicking Chemoembolization for Cancer Therapy

Constructing ROS-Responsive Supramolecular Gel with Innate Antibacterial Properties

Bacterial infections, especially antibiotic-resistant bacterial infections, pose a significant threat to human health. Supramolecular gel with innate antibacterial properties is an advanced material for the treatment of bacterial infections, which have attracted great attention. Herein, a reactive oxygen species (ROS)-responsive innate antibacterial supramolecular gel is developed by a bottom-up approach based on phenylalanine and hydrazide with innate antibacterial properties. The structure of gelators and intermediate products was characterized by proton nuclear magnetic resonance (1H NMR) and a high-resolution mass spectrum (HRMS). The results of 1H NMR and the Fourier transform infrared spectrum (FT-IR) experiment disclosed that hydrogen bonding and the π-π stacking force are the important self-assembly driving forces of gelators. The microstructure and mechanical properties of gel were studied by Scanning electron microscope (SEM) and Rheometer, respectively. An in vitro degradation experiment proved that the gelator has ROS-responsive degradation properties. The in vitro drug release experiment further manifested that antibiotic-loaded gel has ROS-responsive drug-release performances. An in vitro cytotoxicity experiment showed that the supramolecular gel has good biocompatibility and could promote cell proliferation. The in vitro antibacterial experiment proved that the supramolecular gel has excellent inherent antibacterial properties, and the antibacterial rate against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was 98.6% and 99.1%, respectively. The ROS-responsive supramolecular gel as a novel antibacterial agent has great application prospects in treating antibiotic-resistant bacterial-infected wounds and preventing the development of bacterial resistance.

A Novel Drug Self-Delivery System from Fatty Alcohol Esters of Tranexamic Acid for Venous Malformation Sclerotherapy

Venous malformation (VM), which causes severe damage to patients' appearance and organ function, is one of the most common vascular malformations. At present, many drugs in clinical treatment cause various adverse reactions. Herein, we synthesized cationic amphiphilic gelators (TA6, TA8, and TA9) by introducing saturated carbon chains of different lengths to tranexamic acid (TA), which could self-assemble into low-molecular-weight gels (LMWGs) as drug delivery carriers by hydrogen bonds, van der Waals forces, and hydrophobic interactions. The rheological properties, gelation driving force and drug release profiles of TA6, TA8, and TA9 hydrogels were characterized, and the results indicated that the hydrogels prepared in this study possessed the typical characteristics of a gel and could release drugs slowly. More importantly, the TA9 gelator showed significant pharmacological activity, in that it served as both an active drug compound and a drug carrier. The in vitro experiments demonstrated that TA9 induced HUVECs death and hemolysis by destroying cell membranes in a dose-dependent manner, and caused cell death and hemolysis at a concentration of 0.09 µM/mL. Meanwhile, we found TA9 could interact not only with fibrinogen, but also with other endogenous molecules in the blood. After the administration of TA9 hydrogel for 15 days, macroscopic imaging and histological evaluation in mice and rabbits displayed obvious thrombi, inflammatory reactions, and venous embolization, indicating that the mechanism of the TA9 hydrogel in treating VM was involved in two processes. Firstly, the TA9 hydrogel relied on its mechanical strength to physically block veins and continuously release TA9, in situ, for targeted therapy. Then, TA9 destroyed endothelial cells and damaged venous walls critically, causing thrombi. Most excitingly, TA9 was hydrolyzed to TA by enzymes that inhibited the degradation of thrombi by plasmin to prolong the embolization time and to promote venous fibrosis. Compared with other clinically available sclerosants, the degradation of TA9 also empowered a better biocompatibility and biodegradability for the TA9 hydrogel. In conclusion, we synthesized a potentially safe and effective derivative of TA and developed a low-molecular-weight gel as a self-delivery system for TA in treating VM.

Designing a Transparent and Fluorine Containing Hydrogel

Physical hydrogels are supramolecular materials obtained by self-assembly of small molecules called gelators. Aromatic amino acids and small peptides containing aromatic rings are good candidates as gelators due to their ability to form weak bonds as π-π interactions and hydrogen bonds between NH and CO of the peptide chain. In this paper we show our results in the preparation of a transparent hydrogel that was obtained by self-assembly of a fluorine-containing dipeptide that relies on the additional formation of halogen bonds due to the fluorine atoms contained in the dipeptide. We used Boc-D-F2Phe-L-Oxd-OH (F2Phe = 3,4-difluorophenylalainine; Oxd = 4-methyl-5-carboxy-oxazolidin-2-one) that formed a strong and transparent hydrogel in 0.5% w/w concentration at pH = 4.2. The formation of a hydrogel made of unnatural fluorinated amino acids may be of great interest in the evaluation of patients with parkinsonian syndromes and may be used for controlled release.

Blood circulation stable doxorubicin prodrug nanoparticles containing hydrazone and thioketal moieties for antitumor chemotherapy

Prodrug nanoparticles with cleavable moieties sensitive to intracellular stimuli have drawn great attention on cancer chemotherapy. Herein, a reactive oxygen species (ROS)-responsive doxorubicin prodrug mPEG-Phe-TK-Phe-hyd-DOX was synthesized, in which hydrophilic methoxy poly(ethylene glycol) (mPEG) and hydrophobic anticancer drug doxorubicin (DOX) were conjugated with hydrazone (hyd) and ROS-responsive thioketal (TK) moieties. The ROS-responsiveness of prodrug was confirmed by proton nuclear magnetic resonance (¹H NMR) and dynamic light scattering (DLS). Unexpectedly, the results of in vitro drug release indicated that the hydrazone bond of prodrug nanoparticles was insensitive to pH, which may be due to the strong hydrophobicity, π-π interactions and cation-π interactions jointly inhibited the hydrolysis of hydrazone bonds under acidic conditions. The cellular uptake and in vitro anticancer study showed that ROS-responsive prodrug nanoparticles exhibited faster cellular uptake and better anticancer efficacy. The in vivo experiments showed that the ROS-responsive prodrug nanoparticles had comparable antitumor efficacy with free anticancer drug DOX and reduced organ toxicity. Our results provide novel idea of successfully design multi-stimuli-responsive nano-drug carrier.

Facile construction of a family of supramolecular gels with good levofloxacin hydrochloride loading capacity

A family of low molecular weight gelators with different alkyl chain lengths was constructed, having excellent gelation ability and antibiotic loading capacity. A low molecular weight hydrogelator was obtained by adjusting the length of alkyl chain.

Prussian blue nanosphere-embedded in situ hydrogel for photothermal therapy by peritumoral administration

To establish an injectable hydrogel containing Prussian blue (PB) nanospheres for photothermal therapy against cancer, PB nanospheres were prepared by one-pot synthesis and the thermosensitive Pluronic F127 was used as the hydrogel matrix. The PB nanospheres and the hydrogel were characterized by shape, particle size, serum stability, photothermal performance upon repeated 808 nm laser irradiation, as well as the rheological features. The effect of the PB nanospheres and the hydrogel were evaluated qualitatively and quantitatively in 4T1 mouse breast cancer cells. The retention, photothermal efficacy, therapeutic effects and systemic toxicity of the hydrogel were assessed in a tumor-bearing mouse model. The PB nanospheres had a diameter of about 150 nm and exhibited satisfactory serum stability, photo-heat convert ability and repeated laser exposure stability. The hydrogel encapsulation did not negatively influence the above features of the photothermal agent. The nanosphere-containing hydrogel showed a phase transition at body temperature and, as a result, a long retention time in vivo. The photothermal agent-embedded hydrogel displayed promising photothermal therapeutic effects in the tumor-bearing mouse model with little-to-no systemic toxicity after peritumoral administration.

A reactive oxygen species (ROS)-responsive low molecular weight gel co-loaded with doxorubicin and Zn(ii) phthalocyanine tetrasulfonic acid for combined chemo-photodynamic therapy

A ROS-responsive low molecular weight hydrogel was fabricated and loaded with an anticancer drug and a photosensitizer for efficient chemo-photodynamic therapy.