A multifunctional injectable, self-healing, and adhesive hydrogel-based wound dressing stimulated diabetic wound healing with combined reactive oxygen species scavenging, hyperglycemia reducing, and bacteria-killing abilities.

The proficient handling of diabetic wounds, a rising issue coinciding with the global escalation of diabetes cases, poses significant clinical difficulties. A range of biofunctional dressings have been engineered and produced to expedite the healing process of diabetic wounds. This study proposes a multifunctional hydrogel dressing for diabetic wound healing, which is composed of Polyvinyl Alcohol (PVA) and N1-(4-boronobenzyl)-N3-(4-boronophenyl)-N1, N1, N3, N3-teramethylpropane-1, 3-diaminium (TSPBA), and a dual-drug loaded Gelatin methacryloyl (GM) microgel. The GM microgel is loaded with sodium fusidate (SF) and nanoliposomes (LP) that contain metformin hydrochloride (MH). Notably, adhesive and self-healing properties the hydrogel enhance their therapeutic potential and ease of application. In vitro assessments indicate that SF-infused hydrogel can eliminate more than 98% of bacteria within 24 h and maintain a sustained release over 15 days. Additionally, MH incorporated within the hydrogel has demonstrated effective glucose level regulation for a duration exceeding 15 days. The hydrogel demonstrates a sustained ability to neutralize ROS throughout the entire healing process, predominantly by electron donation and sequestration. This multifunctional hydrogel dressing, which integrated biological functions of efficient bactericidal activity against both MSSA and MRSA strains, blood glucose modulation, and control of active oxygen levels, has successfully promoted the healing of diabetic wounds in rats in 14 days. The hydrogel dressing exhibited significant effectiveness in facilitating the healing process of diabetic wounds, highlighting its considerable promise for clinical translation.

NIR-activated electrospun nanodetonator dressing enhances infected diabetic wound healing with combined photothermal and nitric oxide-based gas therapy.

Diabetic wounds pose a challenge to healing due to increased bacterial susceptibility and poor vascularization. Effective healing requires simultaneous bacterial and biofilm elimination and angiogenesis stimulation. In this study, we incorporated polyaniline (PANI) and S-Nitrosoglutathione (GSNO) into a polyvinyl alcohol, chitosan, and hydroxypropyltrimethyl ammonium chloride chitosan (PVA/CS/HTCC) matrix, creating a versatile wound dressing membrane through electrospinning. The dressing combines the advantages of photothermal antibacterial therapy and nitric oxide gas therapy, exhibiting enduring and effective bactericidal activity and biofilm disruption against methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. Furthermore, the membrane's PTT effect and NO release exhibit significant synergistic activation, enabling a nanodetonator-like burst release of NO through NIR irradiation to disintegrate biofilms. Importantly, the nanofiber sustained a uniform release of nitric oxide, thereby catalyzing angiogenesis and advancing cellular migration. Ultimately, the employment of this membrane dressing culminated in the efficacious amelioration of diabetic-infected wounds in Sprague-Dawley rats, achieving wound closure within a concise duration of 14 days. Upon applying NIR irradiation to the PVA-CS-HTCC-PANI-GSNO nanofiber membrane, it swiftly eradicates bacteria and biofilm within 5 min, enhancing its inherent antibacterial and anti-biofilm properties through the powerful synergistic action of PTT and NO therapy. It also promotes angiogenesis, exhibits excellent biocompatibility, and is easy to use, highlighting its potential in treating diabetic wounds.

Establishment of a bi-layered tissue engineered conjunctiva using a 3D-printed melt electrowritten poly-(ε-caprolactone) scaffold.

PURPOSE: To utilize melt electrowriting (MEW) technology using poly-(ε-caprolactone) (PCL) coupled with a 2-step co-culturing strategy for the development of a conjunctival bi-layer synthetic construct. METHODS: Melt electrowritten scaffolds using PCL were fabricated using an in-house-built MEW printer. Human conjunctival stromal cells (CjSCs) and epithelial cells (CjECs) were isolated from donor tissue. A 2-step co-culture method was done by first seeding the CjSCs and culturing for 4 weeks to establish a stromal layer, followed by CjECs and co-culturing for 2 more weeks. Cultured cells were each characterized by morphology and marker expression on immunofluorescence and qPCR. The produced construct was assessed for cellular proliferation using viability assays. The bi-layer morphology was assessed using scanning electron microscopy (SEM), confocal microscopy, and immunofluorescence imaging. The expression of extracellular matrix components and TGF-b was evaluated using qPCR. RESULTS: CjSCs were spindle-shaped and vimentin + while CjECs were polygonal and CK13 + . CjSCs showed consistent proliferation and optimal adherence with the scaffold at the 4-week culture mark. A 2-layered construct consisting of a CjSC-composed stromal layer and a CjEC-composed epithelial layer was appreciated on confocal microscopy, SEM, and immunofluorescence. CjSCs secreted collagens (types I, V, VI) but at differing amounts from natural tissue while TGF-b production was comparable. CONCLUSION: The 3D-printed melt electrowritten PCL scaffold paired with the 2-step co-culturing conditions of the scaffold allowed for the first approximation of a bi-layered stromal and epithelial reconstruction of the conjunctiva that can potentially improve the therapeutic arsenal in ocular surface reconstruction.

A new strategy to sustained release of ocular drugs by one-step drug-loaded microcapsule manufacturing in hydrogel punctal plugs.

PURPOSE: To design an injectable hyaluronate (HA)-based hydrogel system that contains drug-loaded microcapsules as resorbable plugs to deliver ocular drugs. METHODS: In-situ drug-loaded, core-shell-structured chitosan (CS)@HA microcapsules were fabricated via HA hydrosol collecting in electrospun bead-rich CS fibers under continuous stirring. An injectable and cytocompatible hydrogel system with different degrees of chemical crosslinking maintained viscoelastic and sustained drug release for a long-term period of time at body temperature in vitro. RESULTS: With the addition of adipic dihydrazide (ADH) or 1-Ethyl-3-(3-dimethyllaminopropyl) carbodiimide hydrochloride (EDCI), HA hydrosols transited from liquid to solid state at the gel point, with the G'/G″ ratio varying between 1.43 and 5.32 as a function of crosslinker concentration in the hydrogel phase. Ofloxacin (OFL) release from the mechanically mixed hydrosol system (CS-HA-A0-E0) and the micro-encapsulated hydrosol formulation (CS@HA-A0-E0) were respectively over 80% and 51% of the total drug load leaching out within 24 h. As for the drug-mixed hydrogel systems with low (CS-HA-A0.06-E0.15) and high (CS-HA-A0.06-E0.30) crosslinking density, the OFL release rate reached 38.5 and 46.6% respectively, while the micro-encapsulated hydrogel systems with low (CS@HA-A0.06-E0.15) and high (CS@HA-A0.6-E0.30) showed only (11.9 ± 2.7)% and (17.4 ± 3.5)% drug release respectively. CONCLUSIONS: A one-step in-situ drug-capsulizing method is developed to fabricate a resorbable hydrogel punctal plug with extended drug release. The chemistry of the crosslinking reaction involves the formation of highly biocompatible HA derivatives. Thus, the hydrogel can be used directly in the tear drainage canalicular system.

Injectable thermo-responsive Poloxamer hydrogel/methacrylate gelatin microgels stimulates bone regeneration through biomimetic programmed release of SDF-1a and IGF-1.

Injectable hydrogels, offering adaptable drug delivery of growth factors (GFs), hold promise for treating bone defects. To optimize osteogenic efficacy, the release of GFs should mirror the natural bone healing. We developed an injectable thermo-responsive hydrogel/microgels platform for dual GF delivery for bone regeneration. Stromal cell-derived factor-1 alpha (SDF-1a) and the Methacrylate Gelatin (GelMA) microgels which encapsulated insulin-like growth factor-1 (IGF-1) loaded liposomes (Ls) were introduced into Poloxamer 407 (P407) hydrogel matrix. This system achieved the biomimetic release profile of SDF-1a and IGF-1, which covered the early stage from day 1 to 7 and the continuous stage from day 5 to 21, respectively. In vitro study confirmed the enhanced migration, osteogenic biomarker expression, and matrix mineralization of the bone marrow mesenchymal stem cells (BMSCs) co-cultivated with the dual GFs delivering hydrogel/microgels. Transcriptome sequencing revealed that the potential mechanism was associated with mitogen-activated protein kinase (MAPK) signaling activation and its downstream ribosomal protein S6 kinase 2 (RSK2) upregulation. In a critical-sized calvarial defect model in Sprague-Dawley (SD) rats, the injectable hydrogel/microgels system promoted significant bone regeneration. Collectively, our study suggested the current hydrogel/microgels system with the biomimetic release of SDF-1a and IGF-1 efficiently promoted bone regeneration, informing the future development of GF delivery systems intended for bone regeneration therapies.

Electrospun polyvinyl alcohol-chitosan dressing stimulates infected diabetic wound healing with combined reactive oxygen species scavenging and antibacterial abilities.

Diabetic wounds (DW) are constantly challenged by excessive reactive oxygen species (ROS) accumulation and susceptibility to bacterial contamination. Therefore, the elimination of ROS in the immediate vicinity and the eradication of local bacteria are critical to stimulating the efficient healing of diabetic wounds. In the current study, we encapsulated mupirocin (MP) and cerium oxide nanoparticles (CeNPs) into a polyvinyl alcohol/chitosan (PVA/CS) polymer, and then a PVA/chitosan nanofiber membrane wound dressing was fabricated using electrostatic spinning, which is a simple and efficient method for fabricating membrane materials. The PVA/chitosan nanofiber dressing provided a controlled release of MP, which produced rapid and long-lasting bactericidal activity against both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains. Simultaneously, the CeNPs embedded in the membrane exhibited the desired ROS scavenging capacity to maintain the local ROS at a normal physiological level. Moreover, the biocompatibility of the multifunctional dressing was evaluated both in vitro and in vivo. Taken together, PVA-CS-CeNPs-MP integrated the desirable features of a wound dressing, including rapid and broad-spectrum antimicrobial and ROS scavenging activities, easy application, and good biocompatibility. The results validated the effectiveness of our PVA/chitosan nanofiber dressing, highlighting its promising translational potential in the treatment of diabetic wounds.

Cytoprotective effect of hyaluronic acid and hydroxypropyl methylcellulose against DNA damage induced by thimerosal in Chang conjunctival cells.

BACKGROUND: To investigate genotoxicity of the preservative thimerosal (Thi), and the cytoprotective and antioxidant effects of hyaluronic Acid (HA) and hydroxypropyl methylcellulose (HPMC) on Chang conjunctival cells. METHOD: Cells were divided into three groups. One group was exposed to Thi at various concentrations (0.00001 %∼0.001 %) for 30 min; the other two groups were pretreated with 0.3 % HA or 0.3 % HPMC for 30 min before the Thi exposure. After cell viability was evaluated, alkaline comet assay and detection of the phosphorylated form of the histone variant H2AX (γH2AX) foci were used to determine DNA damage. Reactive oxygen species (ROS) production was assessed by the fluorescent probe, 2', 7'-dichlorodihydrofluorescein diacetate (DCFH-DA). RESULTS: A significant change of cell viability was observed after exposure to 0.001 % Thi for 30 min. DNA single- and double-strand breaks were significantly increased in a dose-dependent manner with Thi exposure. In addition, intracellular ROS induced by Thi was dose-dependent, except at 0.001 % less ROS was induced than at 0.0005 %. However, cells pretreated with 0.3 % HA or 0.3 % HPMC showed significantly increased cell survival, decreased DNA damage, and decreased ROS production compared to cells exposed to Thi alone. Pretreatment with 0.3 % HA was found to be even more protective than 0.3 % HPMC. CONCLUSION: Thi can induce DNA damage in human conjunctival epithelial cells, probably due to oxidative stress. HA and HPMC are protective agents that have antioxidant properties and can decrease DNA damage induced by Thi. Pretreatment of 0.3 % HA may be more protective of the ocular surface than 0.3 % HPMC.

Precisely Tuning the Pore-Wall Surface Composition of Bioceramic Scaffolds Facilitates Angiogenesis and Orbital Bone Defect Repair.

Orbital bone damage (OBD) may result in severe post-traumatic enophthalmos, craniomaxillofacial deformities, vision loss, and intracranial infections. However, it is still a challenge to fabricate advanced biomaterials that can match the individual anatomical structure and enhance OBD repair in situ. Herein, we aimed to develop a selective surface modification strategy on bioceramic scaffolds and evaluated the effects of inorganic or organic functional coating on angiogenesis and osteogenesis, ectopically and orthotopically in OBD models. It was shown that the low thermal bioactive glass (BG) modification or layer-by-layer assembly of a biomimetic hydrogel (Biogel) could readily integrate into the pore wall of the bioceramic scaffolds. The BG and Biogel modification showed appreciable enhancement in the initial compressive strength (∼30-75%) or structural stability in vivo, respectively. BG modification could enhance by nearly 2-fold the vessel ingrowth, and the osteogenic capacity was also accelerated, accompanied with a mild scaffold biodegradation after 3 months. Meanwhile, the Biogel-modified scaffolds showed enhanced osteogenic differentiation and mineralization through calcium and phosphorus retention. The potential mechanism of the enhanced bone repair was elucidated via vascular and osteogenic cell responses in vitro, and the cell tests indicated that the Biogel and BG functional layers were both beneficial for in vitro osteoblastic differentiation and mineralization on bioceramics. Totally, these findings demonstrated that the bioactive ions or biomolecules could significantly improve the angiogenic and osteogenic capabilities of conventional bioceramics, and the integration of inorganic or organic functional coating in the pore wall is a highly flexible material toolbox that can be tailored directly to improve orbital bone defect repair.

Tissue engineering of corneal stroma via melt electrowriting.

The cornea serves as the main refractive component of the eye with the corneal stroma constituting the thickest component in a stratified layered system of epithelia, stroma, and endothelium. Current treatment options for patients suffering from corneal diseases are limited to transplantation of a human donor cornea (keratoplasty) or to implantation of an artificial cornea (keratoprosthesis). Nevertheless, donor shortage and failure of artificial corneas to integrate with local tissue constitute important problems that have not been yet circumvented. Recent advances in biofabrication have made great progress toward the manufacture of tailored biomaterial templates with the potential of guiding partially or totally the regeneration process of the native cornea. However, the role of the corneal stroma on current tissue engineering strategies is often neglected. Here, we achieved a tissue-engineered corneal stroma substitute culturing primary keratocytes on scaffolds prepared via melt electrowriting (MEW). Scaffolds were designed to contain highly organized micrometric fibers to ensure transparency and encourage primary human keratocytes to self-orchestrate their own extracellular matrix deposition and remodeling. Results demonstrated reliable cell attachment and growth over a period of 5 weeks and confirmed the formation of a dense and highly organized de novo tissue containing collagen I, V, and VI as well as Keratocan, which resembled very closely the native corneal stoma. In summary, MEW brings us closer to the biofabrication of a viable corneal stroma substitute.

Unilateral Levator Aponeurosis Excision for Marcus Gunn Syndrome and Risk Factors of Residual Jaw Winking.

PURPOSE: To investigate the association of ptosis, levator, and jaw winking in Marcus Gunn jaw-winking synkinesis (MGJWS), and the risk factor of preservation and outcomes of the unilateral levator excision and frontalis suspension. METHODS: Clinical features of MGJWS case series from 2011 to 2018 were retrospectively reviewed. Association between jaw winking and ptosis/levator function was statistically analyzed. The patients underwent unilateral levator excision and frontalis suspension using silicone rod or autogenous fascia lata. Clinical outcomes were evaluated in operated patients and the independent risk factors of residual jaw winking were investigated after a long follow-up. RESULTS: There were 42 MGJWS patients in 2011 to 2018, accounting for 2.87% of all congenital blepharoptosis. 80% of mild jaw winking was accompanied with mild ptosis and fair levator function, and moderate-to-severe jaw winking was often accompanied with moderate-to-severe ptosis and poor levator function (P < 0.05). Ptosis showed a strong association with excursion of jaw winking (R = 0.785, P < 0.01). Jaw winking was resolved in all 34 operated patients with good correction of ptosis. Severity of jaw winking is an independent risk factor for the residual synkinesis after surgery. Severe preoperative jaw winking had an 18.05 times increased risk of postoperative residual synkinesis compared with moderate jaw winking (P < 0.05). CONCLUSIONS: In MGJWS eyelid excursion of jaw winking has a direct correlation with ptosis and dysfunction of levator muscle. Unilateral levator aponeurosis excision and frontalis suspension is an efficient approach for MGJWS. Severe jaw winking is a risk factor of residual eyelid synkinesis after surgery.

Exposure rate of unwrapped hydroxyapatite orbital implants in enucleation surgery.

OBJECTIVE: To document the long-term exposure rate of unwrapped coralline hydroxyapatite (HA) orbital implants and explore possible risk factors. DESIGN: This retrospective case series (May 2008-April 2013) reviewed the 234 patients with anophthalmia who underwent insertion of an unwrapped HA orbital implant by one of two different surgical closing techniques. RESULTS: Of the 234 cases, 151 underwent a rectus end-to-end suturing closure technique and 83 underwent a rectus orthotopic suturing closure technique. The time of follow-up ranged from 25 months to 69 months (mean 41.9 months). Implant exposure developed in 11 cases. Three in the rectus end-to-end suturing closure group (2.0%) and eight in the rectus orthotopic suturing closure group (9.6%). In the rectus end-to-end suturing technique, a crosswise fixation of vascularised rectus muscle tissue is formed across the front of the implant; in this group the incidence of implant exposure was reduced (OR=8.11, p=0.013). Prior ocular surgery was found to be a factor increasing the incidence of HA exposure (OR=2.73, p=0.032). CONCLUSIONS: The placement of an unwrapped HA orbital implant with rectus end-to-end suturing in enucleation surgery was associated with a low rate of exposure in most cases. The end-to-end suturing creates a joint-like structure over the HA sphere, protecting the Tenon's capsule and conjunctiva from its rough surface and reducing the risk of implant exposure. Prior ocular surgery may be another risk factor for HA exposure.