Local Immunomodulation Using an Adhesive Hydrogel Loaded with miRNA-Laden Nanoparticles Promotes Wound Healing.

Chronic wounds are characterized by impaired healing and uncontrolled inflammation, which compromise the protective role of the immune system and may lead to bacterial infection. Upregulation of miR-223 microRNAs (miRNAs) shows driving of the polarization of macrophages toward the anti-inflammatory (M2) phenotype, which could aid in the acceleration of wound healing. However, local-targeted delivery of microRNAs is still challenging, due to their low stability. Here, adhesive hydrogels containing miR-223 5p mimic (miR-223*) loaded hyaluronic acid nanoparticles are developed to control tissue macrophages polarization during wound healing processes. In vitro upregulation of miR-223* in J774A.1 macrophages demonstrates increased expression of the anti-inflammatory gene Arg-1 and a decrease in proinflammatory markers, including TNF-α, IL-1ß, and IL-6. The therapeutic potential of miR-223* loaded adhesive hydrogels is also evaluated in vivo. The adhesive hydrogels could adhere to and cover the wounds during the healing process in an acute excisional wound model. Histological evaluation and quantitative polymerase chain reaction (qPCR) analysis show that local delivery of miR-223* efficiently promotes the formation of uniform vascularized skin at the wound site, which is mainly due to the polarization of macrophages to the M2 phenotype. Overall, this study demonstrates the potential of nanoparticle-laden hydrogels conveying miRNA-223* to accelerate wound healing.

Engineering injectable, biocompatible, and highly elastic bioadhesive cryogels.

The extracellular matrix (ECM), an integral component of all organs, is inherently tissue adhesive and plays a pivotal role in tissue regeneration and remodeling. However, man-made three-dimensional (3D) biomaterials that are designed to mimic ECMs do not intrinsically adhere to moisture-rich environments and often lack an open macroporous architecture required for facilitating cellularization and integration with the host tissue post-implantation. Furthermore, most of these constructs usually entail invasive surgeries and potentially a risk of infection. To address these challenges, we recently engineered biomimetic and macroporous cryogel scaffolds that are syringe injectable while exhibiting unique physical properties, including strong bioadhesive properties to tissues and organs. These biomimetic catechol-containing cryogels were prepared from naturally-derived polymers such as gelatin and hyaluronic acid and were functionalized with mussel-inspired dopamine (DOPA) to impart bioadhesive properties. We found that using glutathione as an antioxidant and incorporating DOPA into cryogels via a PEG spacer arm led to the highest tissue adhesion and improved physical properties overall, whereas DOPA-free cryogels were weakly tissue adhesive. As shown by qualitative and quantitative adhesion tests, DOPA-containing cryogels were able to adhere strongly to several animal tissues and organs such as the heart, small intestine, lung, kidney, and skin. Furthermore, these unoxidized (i.e., browning-free) and bioadhesive cryogels showed negligible cytotoxicity toward murine fibroblasts and prevented the ex vivo activation of primary bone marrow-derived dendritic cells. Finally, in vivo data suggested good tissue integration and a minimal host inflammatory response when subcutaneously injected in rats. Collectively, these minimally invasive, browning-free, and strongly bioadhesive mussel-inspired cryogels show great promise for various biomedical applications, potentially in wound healing, tissue engineering, and regenerative medicine.

Co-Encapsulation of Violacein and Iron Oxide in Poly(lactic acid) Nanoparticles for Simultaneous Antibacterial and Anticancer Applications.

To date, the possibility of drug-resistant bacterial infections in hospitals and intensive care units comprises a significant concern especially for immunocompromised cancer patients. In the current study, violacein and superparamagnetic iron oxide nanoparticles were co-encapsulated in polylactic acid nanoparticles (vio-Fe3O4-PLA) and tested for their antimicrobial and anticancer activity. The loaded nanoparticles presented efficient saturation magnetization that rendered this nanosystem a promising candidate for magnetic targeting. Moreover, violacein released from the nanoparticles at 500 µg/mL successfully inhibited the growth of the "superbug" methicillin-resistant Staphylococcus aureus (MRSA) with an IC50 value of 595.8 µg/mL, while it did not prove effective against multi-drug-resistant Escherichia coli at concentrations of 10-1000 µg/mL. Finally, a concentration of 500 µg/mL of drug loaded magnetic nanoparticles induced an over 80% growth inhibition of glioblastoma and melanoma cancer cell lines with IC50 values of 221.30 and 201.60 µg/mL, respectively. Since bacterial infections are a key clinical problem for cancer patients due to their compromised immune systems, the presented results suggest that our system should be further studied for its simultaneous anti-bacterial and anti-cancer properties, as it comprises a promising strategy for combating bacterial infections and providing anticancer activity through magnetic-targeted delivery.

Engineering a naturally derived hemostatic sealant for sealing internal organs.

Controlling bleeding from a raptured tissue, especially during the surgeries, is essentially important. Particularly for soft and dynamic internal organs where use of sutures, staples, or wires is limited, treatments with hemostatic adhesives have proven to be beneficial. However, major drawbacks with clinically used hemostats include lack of adhesion to wet tissue and poor mechanics. In view of these, herein, we engineered a double-crosslinked sealant which showed excellent hemostasis (comparable to existing commercial hemostat) without compromising its wet tissue adhesion. Mechanistically, the engineered hydrogel controlled the bleeding through its wound-sealing capability and inherent chemical activity. This mussel-inspired hemostatic adhesive hydrogel, named gelatin methacryloyl-catechol (GelMAC), contained covalently functionalized catechol and methacrylate moieties and showed excellent biocompatibility both in vitro and in vivo. Hemostatic property of GelMAC hydrogel was initially demonstrated with an in vitro blood clotting assay, which showed significantly reduced clotting time compared to the clinically used hemostat, Surgicel®. This was further assessed with an in vivo liver bleeding test in rats where GelMAC hydrogel closed the incision rapidly and initiated blood coagulation even faster than Surgicel®. The engineered GelMAC hydrogel-based seaalant with excellent hemostatic property and tissue adhesion can be utilized for controlling bleeding and sealing of soft internal organs.

Biological Applications of Severely Plastically Deformed Nano-Grained Medical Devices: A Review.

Metallic materials are widely used for fabricating medical implants due to their high specific strength, biocompatibility, good corrosion properties, and fatigue resistance. Recently, titanium (Ti) and its alloys, as well as stainless steel (SS), have attracted attention from researchers because of their biocompatibility properties within the human body; however, improvements in mechanical properties while keeping other beneficial properties unchanged are still required. Severe plastic deformation (SPD) is a unique process for fabricating an ultra-fine-grained (UFG) metal with micrometer- to nanometer-level grain structures. SPD methods can substantially refine grain size and represent a promising strategy for improving biological functionality and mechanical properties. This present review paper provides an overview of different SPD techniques developed to create nano-/ultra-fine-grain-structured Ti and stainless steel for improved biomedical implant applications. Furthermore, studies will be covered that have used SPD techniques to improve bone cell proliferation and function while decreasing bacterial colonization when cultured on such nano-grained metals (without resorting to antibiotic use).

Nanoengineered shear-thinning and bioprintable hydrogel as a versatile platform for biomedical applications.

The development of bioinks based on shear-thinning and self-healing hydrogels has recently attracted significant attention for constructing complex three-dimensional physiological microenvironments. For extrusion-based bioprinting, it is challenging to provide high structural reliability and resolution of printed structures while protecting cells from shear forces during printing. Herein, we present shear-thinning and printable hydrogels based on silicate nanomaterials, laponite (LA), and glycosaminoglycan nanoparticles (GAGNPs) for bioprinting applications. Nanocomposite hydrogels (GLgels) were rapidly formed within seconds due to the interactions between the negatively charged groups of GAGNPs and the edges of LA. The shear-thinning behavior of the hydrogel protected encapsulated cells from aggressive shear stresses during bioprinting. The bioinks could be printed straightforwardly into shape-persistent and free-standing structures with high aspect ratios. Rheological studies demonstrated fast recovery of GLgels over multiple strain cycles. In vitro studies confirmed the ability of GLgels to support cell growth, proliferation, and spreading. In vitro osteogenic differentiation of pre-osteoblasts murine bone marrow stromal cells encapsulated inside the GLgels was also demonstrated through evaluation of ALP activity and calcium deposition. The subcutaneous implantation of the GLgel in rats confirmed its in vivo biocompatibility and biodegradability. The engineered shear-thinning hydrogel with osteoinductive characteristics can be used as a new bioink for 3D printing of constructs for bone tissue engineering applications.

Nanoengineered Shear-Thinning Hydrogel Barrier for Preventing Postoperative Abdominal Adhesions.

More than 90% of surgical patients develop postoperative adhesions, and the incidence of hospital re-admissions can be as high as 20%. Current adhesion barriers present limited efficacy due to difficulties in application and incompatibility with minimally invasive interventions. To solve this clinical limitation, we developed an injectable and sprayable shear-thinning hydrogel barrier (STHB) composed of silicate nanoplatelets and poly(ethylene oxide). We optimized this technology to recover mechanical integrity after stress, enabling its delivery though injectable and sprayable methods. We also demonstrated limited cell adhesion and cytotoxicity to STHB compositions in vitro. The STHB was then tested in a rodent model of peritoneal injury to determine its efficacy preventing the formation of postoperative adhesions. After two weeks, the peritoneal adhesion index was used as a scoring method to determine the formation of postoperative adhesions, and STHB formulations presented superior efficacy compared to a commercially available adhesion barrier. Histological and immunohistochemical examination showed reduced adhesion formation and minimal immune infiltration in STHB formulations. Our technology demonstrated increased efficacy, ease of use in complex anatomies, and compatibility with different delivery methods, providing a robust universal platform to prevent postoperative adhesions in a wide range of surgical interventions.

Ciprofloxacin-loaded bioadhesive hydrogels for ocular applications.

The management of corneal infections often requires complex therapeutic regimens involving the prolonged and high-frequency application of antibiotics that provide many challenges to patients and impact compliance with the therapeutic regimens. In the context of severe injuries that lead to tissue defects (e.g. corneal lacerations) topical drug regimens are inadequate and suturing is often indicated. There is thus an unmet need for interventions that can provide tissue closure while concurrently preventing or treating infection. In this study, we describe the development of an antibacterial bioadhesive hydrogel loaded with micelles containing ciprofloxacin (CPX) for the management of corneal injuries at risk of infection. The in vitro release profile showed that the hydrogel system can release CPX, a broad-spectrum antibacterial drug, for up to 24 h. Moreover, the developed CPX-loaded hydrogels exhibited excellent antibacterial properties against Staphylococcus aureus and Pseudomonas aeruginosa, two bacterial strains responsible for the most ocular infections. Physical characterization, as well as adhesion and cytocompatibility tests, were performed to assess the effect of CPX loading in the developed hydrogel. Results showed that CPX loading did not affect stiffness, adhesive properties, or cytocompatibility of hydrogels. The efficiency of the antibacterial hydrogel was assessed using an ex vivo model of infectious pig corneal injury. Corneal tissues treated with the antibacterial hydrogel showed a significant decrease in bacterial colony-forming units (CFU) and a higher corneal epithelial viability after 24 h as compared to non-treated corneas and corneas treated with hydrogel without CPX. These results suggest that the developed adhesive hydrogel system presents a promising suture-free solution to seal corneal wounds while preventing infection.

The Potential Anticancer Activity of 5-Fluorouracil Loaded in Cellulose Fibers Isolated from Rice Straw.

INTRODUCTION: Green-based materials have been increasingly studied to circumvent off-target cytotoxicity and other side-effects from conventional chemotherapy. MATERIALS AND METHODS: Here, cellulose fibers (CF) were isolated from rice straw (RS) waste by using an eco-friendly alkali treatment. The CF network served as an anticancer drug carrier for 5-fluorouracil (5-FU). The physicochemical and thermal properties of CF, pure 5-FU drug, and the 5-FU-loaded CF (CF/5-FU) samples were evaluated. The samples were assessed for in vitro cytotoxicity assays using human colorectal cancer (HCT116) and normal (CCD112) cell lines, along with human nasopharyngeal cancer (HONE-1) and normal (NP 460) cell lines after 72-hours of treatment. RESULTS: XRD and FTIR revealed the successful alkali treatment of RS to isolate CF with high purity and crystallinity. Compared to RS, the alkali-treated CF showed an almost fourfold increase in surface area and zeta potential of up to -33.61 mV. SEM images illustrated the CF network with a rod-shaped structure and comprised of ordered aggregated cellulose. TGA results proved that the thermal stability of 5-FU increased within the drug carrier. Based on UV-spectroscopy measurements for 5-FU loading into CF, drug loading encapsulation efficiency was estimated to be 83 ±0.8%. The release media at pH 7.4 and pH 1.2 showed a maximum drug release of 79% and 46%, respectively, over 24 hours. In cytotoxicity assays, CF showed almost no damage, while pure 5-FU killed most of the both normal and cancer cells. Impressively, the drug-loaded sample of CF/5-FU at a 250 µg/mL concentration demonstrated a 58% inhibition against colorectal cancer cells, but only a 23% inhibition against normal colorectal cells. Further, a 62.50 µg/mL concentration of CF/5FU eliminated 71% and 39% of nasopharyngeal carcinoma and normal nasopharyngeal cells, respectively. DISCUSSION: This study, therefore, showed the strong potential anticancer activity of the novel CF/5-FU formulations, warranting their further investigation.

Enzymatic Synthesis of Ricinoleyl Hydroxamic Acid Based on Commercial Castor Oil, Cytotoxicity Properties and Application as a New Anticancer Agent.

BACKGROUND: New anticancer agents that rely on natural/healthy, not synthetic/toxic, components are very much needed. METHODS: Ricinoleyl hydroxamic acid (RHA) was synthesized from castor oil and hydroxylamine using Lipozyme TL IM as a catalyst. To optimize the conversion, the effects of the following parameters were investigated: type of organic solvent, period of reaction, amount of enzyme, the molar ratio of reactants and temperature. The highest conversion was obtained when the reaction was carried out under the following conditions: hexane as a solvent; reaction period of 48 hours; 120 mg of Lipozyme TL IM/3 mmol oil; HA-oil ratio of 19 mmol HA/3 mmol oil; and temperature of 40°C. The cytotoxicity of the synthesized RHA was assessed using human dermal fibroblasts (HDF), and its application towards fighting cancer was assessed using melanoma and glioblastoma cancer cells over a duration of 24 and 48 hours. RESULTS: RHA was successfully synthesized  and it demonstrated strong anticancer activity against glioblastoma and melanoma cells at as low as a 1 µg/mL concentration while it did not demonstrate any toxicity against HDF cells. CONCLUSION: This is the first report on the synthesis of RHA with great potential to be used as a new anticancer agent.

Green Synthesis of Zeolite/Fe2O3 Nanocomposites: Toxicity & Cell Proliferation Assays and Application as a Smart Iron Nanofertilizer.

PURPOSE: The aim of this study was to prepare zeolite/iron (III) oxide nanocomposites (zeolite/Fe2O3-NCs) as a smart fertilizer to improve crop yield and soil productivity. METHODS: Zeolite/Fe2O3-NCs were successfully produced by loading of Fe2O3-NPs onto the zeolite surface using a quick green precipitation method. The production of zeolite/Fe2O3 nanocomposites was performed under a mild condition using environmentally friendly raw materials as a new green chemistry method. The product was characterized using several techniques such as near and far Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). RESULTS: The results confirmed the formation of Fe2O3-NPs with mean particle sizes of 1.45, 2.19, and 2.20 nm on the surface of the zeolite per amount of 4, 7 and 12 wt% Fe2O3-NPs, respectively. Such results indicated that the size of the Fe2O3-NPs did not significantly change when Fe amounts increased from 7 to 12 wt% for the zeolite/Fe2O3-NCs. In terms of medical applications, in vitro cell studies demonstrated that zeolites and zeolite/Fe2O3-NCs were generally non-toxic to human fibroblast cells and significantly pernicious to human malignant melanoma cells. From MTS cytotoxicity assays, the concentration of Fe2O3 within the zeolite/Fe2O3-NCs that was effective at inhibiting the growth of malignant melanoma cells by 50% (the IC50 value) was ~14.9 wt%. The three types of nanocomposites were further tested as an iron smart nanofertilizer for the slow-release of iron ions. CONCLUSION: Advantages of this project include the production of non-toxic nanocomposites as a smart fertilizer to develop crops while the reaction involves the use of commercial and natural materials as low-cost raw materials with low energy usage due to a mild reaction condition, as well as the use of an environmentally friendly solvent (water) with no toxic residues.

Anti-IL-6 eluting immunomodulatory biomaterials prolong skin allograft survival.

A primary goal in the management of burn wounds is early wound closure. The use of skin allografts represents a lifesaving strategy for severe burn patients, but their ultimate rejection limits their potential efficacy and utility. IL-6 is a major pleiotropic cytokine which critically links innate and adaptive immune responses. Here, we devised anti-IL-6 receptor eluting gelatin methacryloyl (GelMA) biomaterials (GelMA/anti-IL-6), which were implanted at the interface between the wound beds and skin allografts. Our visible light crosslinked GelMA/anti-IL-6 immunomodulatory biomaterial (IMB) demonstrated a stable kinetic release profile of anti-IL-6. In addition, the incorporation of anti-IL-6 within the GelMA hydrogel had no effect on the mechanical properties of the hydrogels. Using a highly stringent skin transplant model, the GelMA/anti-IL-6 IMB almost doubled the survival of skin allografts. The use of GelMA/anti-IL-6 IMB was far superior to systemic anti-IL-6 receptor treatment in prolonging skin allograft survival. As compared to the untreated control group, skin from the GelMA/anti-IL-6 IMB group contained significantly fewer alloreactive T cells and macrophages. Interestingly, the environmental milieu of the draining lymph nodes (DLNs) of the mice implanted with the GelMA/anti-IL-6 IMB was also considerably less pro-inflammatory. The percentage of CD4+ IFNγ+ cells was much lower in the DLNs of the GelMA/anti-IL-6 IMB group in comparison to the GelMA group. These data highlight the importance of localized immune delivery in prolonging skin allograft survival and its potential utility in treating patients with severe burns.

Current developments in green synthesis of metallic nanoparticles using plant extracts: a review.

Metal nanoparticles (MNPs) produced by green approaches have received global attention because of their physicochemical characteristics and their applications in the field of biotechnology. In recent years, the development of synthesizing NPs by plant extracts has become a major focus of researchers because of these NPs have low hazardous effect in the environment and low toxicity for the human body. Synthesized NPs from plants are not only more stable in terms of size and shape, also the yield of this method is higher than the other methods. Moreover, some of these MNPs have shown antimicrobial activity which is consistently confirmed in past few years. Plant extracts have been used as reducing agent and stabilizer of NPs in which we can reduce the toxicity in the environment as well as the human body only by not using chemical agents. Furthermore, the presence of some specific materials in plant extracts could be extremely helpful and effective for the human body; for instance, polyphenol, which may have antioxidant effects has the capability for capturing free radicals before they can react with other biomolecules and cause serious damages. In this article, we focused on of the most common plants which are regularly used to synthesize MNPs along with various methods for synthesizing MNPs from plant extracts.