Injectable Tissue Adhesive Microgel Composite Containing Antifibrotic Drug for Vocal Fold Scarring.

Vocal fold (VF) scarring, a complex problem in laryngology, results from injury and inflammation of the layered architecture of the VFs. The resultant voice hoarseness, for which successful therapeutic options are currently limited, affects the patient's quality of life. A promising strategy to reverse this disorder is the use of antifibrotic drugs. The present study proposes a novel microbead-embedded injectable hydrogel that can sustain the release of the anti-fibrotic drug pirfenidone (PFD) for vocal fold scarring. Microbeads were developed using sodium alginate and gelatin, which were further embedded into a biomimetic and tissue adhesive gellan gum (GG) hydrogel. The microbead-embedded hydrogel exhibited improved injectability, viscoelasticity, tissue adhesiveness, degradability, and swelling compared to the hydrogel without beads. Additionally, the bead-embedded hydrogel could sustain the release of the PFD for a week. In vitro studies showed that the drug-loaded hydrogel could reduce the migration and proliferation of fibroblast cells in a dose-dependent manner. In summary, this study demonstrates the potential of a PFD-loaded injectable hydrogel with enhanced viscoelastic and tissue-adhesive properties for vocal fold scarring applications.

Biomimetic kartogenin containing κ-carrageenan hydrogel for nucleus pulposus regeneration.

Intervertebral disc degeneration is a clinical disease that reduces the quality of patient's life. The degeneration usually initiates in the nucleus pulposus (NP), hence the use of hydrogels represents a promising therapeutic approach. However, the viscoelastic nature of hydrogel and its ability to provide biomimetic architecture and biochemical cues influence the regeneration capability. This study focused on tuning the physical nature of a glycosaminoglycan hydrogel (κ-carrageenan) as well as the release kinetics of a chondrogenic factor (kartogenin - KGN) through physical cross-linking. For this, κ-carrageenan was cross linked with 2.5 % and 5 % potassium chloride (KCl) for 15 and 30 min and loaded with KGN molecule at 50 µM and 100 µM. The tight network structure with low water retention and degradation property was seen in hydrogel cross-linked with increased KCl concentration and time. However, optimal degradation along with NP mimicking viscoelastic nature was exhibited by 5 wt% KCl treated hydrogel (H3 hydrogel). All hydrogel groups exhibited burst KGN release at 24 h followed by a sustained release for 5 days. However, hydrogel cross-linked with 5 wt% KCl enhanced chondrogenic differentiation, mainly at lower KGN dose. In summary, this study shows the potential application of biomimetic KGN laden carrageenan hydrogel in NP regeneration.

Nano-graphene oxide particles induce inheritable anomalies through altered gene expressions involved in oocyte maturation.

The inheritable impact of exposure to graphene oxide nanoparticles (GO NPs) on vertebrate germline during critical windows of gamete development remain undetermined to date. Here, we analyzed the transgenerational effects of exposure to nano-graphene oxide particles (nGO) synthesized in house with lateral dimensions 300-600 nm and surface charge of -36.8 mV on different developmental stages of germ cells (GCs): (1) during GCs undergoing early development and differentiation, and (2) during GCs undergoing gametogenesis and maturation in adulthood. Biocompatibility analyses in Japanese medaka embryos showed lethality above 1 µg/ml and also an aberrant increase in germ cell count of both males and females at doses below the lethal dose. However, no lethality or anomalies were evident in adults up to 45 µg/ml. Long term exposure of embryos and adults for 21 days resulted in reduced fecundity. This effect was transmitted to subsequent generations, F1 and F2. Importantly, the inheritable effects of nGO in adults were pronounced at a high dose of 10 µg/ml, while 1 µg/ml showed no impact on the germline indicating lower doses used in this study to be safe. Further, expressions of selected genes that adversely affected oocyte maturation were enhanced in F1 and F2 individuals. Interestingly, the inheritance patterns differed corresponding to the stage at which the fish received the exposure.

Sex-Dependent Bioaccumulation of Nano Zinc Oxide and Its Adverse Effects on Sexual Behavior and Reproduction in Japanese Medaka.

This study investigated the adverse effects of 200 nm zinc oxide particles (nZnO) on sexual behavior and reproduction in Japanese medaka in comparison with ZnSO4 and correlated the consequences with the bioaccumulation pattern of the particles in associated organs. nZnO exposure impaired sexual and territorial behaviors and affected fertility by altering sperm viability and motility in males through reactive oxygen species (ROS) induction. Conversely, none of these effects other than behavior loss was seen in males exposed to ZnSO4. nZnO exposure to females induced ROS in ovaries, causing follicular growth arrest, atresia, and subfertility. Further, sex-steroid levels were altered by both nZnO and ZnSO4 in males and by nZnO but not ZnSO4 in females. Biodistribution studies revealed the deposition of nZnO as particulate matter in the brain, gills, gut, kidney, and ovary. Particle accumulation in the brain was sex specific, as the particles were found in the brain of males but not that of females. A similar trend was seen for zinc levels in males and females exposed to ZnSO4. Importantly, the female sex hormone, 17ß-estradiol was found to prevent nZnO accumulation in the female brain, emphasizing the need for biodistribution profiling of nanoparticle-based drug delivery vehicles separately in males and females before they are commercialized. This study has demonstrated that the toxic effects of nZnO on the reproductive system were mainly caused by ROS induction, while zinc ions were predominantly responsible for the adverse impact of ZnSO4.

Graphene Quantum Dots Alter Proliferation and Meiosis of Germ Cells Only in Genetic Females of Japanese Medaka during Early Embryonic Development.

Graphene quantum dots (GQDs) have emerged as promising biolabeling agents owing to their stable innate fluorescence, photostability, and biocompatibility as opposed to semiconductor quantum dots. While several studies reported GQDs to be cytocompatible, their potential for reproductive toxicity, particularly to germ cells that can cause transgenerational toxicity, remains unexplored. Here we report the intrinsic toxicity of 2-3 nm sized GQDs synthesized from glucose by a novel bottom-up green chemistry technique on germ cell proliferation and meiosis during early embryonic development. In vitro cell viability studies with a normal ovarian cell line, Chinese Hamster Ovarian cells (CHO), and a primary cell type, Human Umbilical Vein Endothelial Cells (HUVEC), portrayed good cytocompatibility even up to a high concentration of 800 µg/mL. When embryos of Japanese medaka were exposed to GQDs, no developmental toxicity was observed up to 250 µg/mL, beyond which hatchability and survival were affected adversely. In contrast, toxicity to germ cells in developing gonads was apparent in genetically female (XX) embryos exposed to much lower doses (50, 75, and 100 µg/mL), at which in vitro cytotoxicity and embryo hatchability and survival were unaffected. A drastic decline in germ cell number and meiosis was observed at these doses in XX embryos implying anomalies in sexual differentiation of the gametes. Conversely, germ cells of genetically male embryos exposed to GQDs were unaltered. Significantly high levels of reactive oxygen species (ROS) were detected in the XX larvae exposed to GQDs; however, there was no DNA damage, suggesting ROS to be responsible for the adverse effects observed.