Potential of Chrysin‐loaded PCL/gelatin nanofibers for modulation of macrophage functional polarity towards anti-inflammatory/pro-regenerative phenotype

Enhanced wound regeneration by PGS/PLA fiber dressing containing platelet-rich plasma: an in vitro study

Novel wound dressings with therapeutic effects are being continually designed to improve the wound healing process. In this study, the structural, chemical, physical, and biological properties of an electrospun poly glycerol sebacate/poly lactide acid/platelet-rich plasma (PGS/PLA-PRP) nanofibers were evaluated to determine its impacts on in vitro wound healing. Results revealed desirable cell viability in the Fibroblast (L929) and macrophage (RAW-264.7) cell lines as well as human umbilical vein endothelial cells (HUVEC). Cell migration was evident in the scratch assay (L929 cell line) so that it promoted scratch contraction to accelerate in vitro wound healing. Moreover, addition of PRP to the fiber structure led to enhanced collagen deposition (~ 2 times) in comparison with PGS/PLA scaffolds. While by addition PRP to PGS/PLA fibers not only decreased the expression levels of pro-inflammatory cytokines (IL-6 and TNF-α) in RAW-264.7 cells but also led to significantly increased levels of cytokine (IL-10) and the growth factor (TGF-β), which are related to the anti-inflammatory phase (M2 phenotype). Finally, PGS/PLA-PRP was found to induce a significant level of angiogenesis by forming branching points, loops, and tubes. Based on the results obtained, the PGS/PLA-PRP dressing developed might be a promising evolution in skin tissue engineering ensuring improved wound healing and tissue regeneration.

Chrysin loaded polycaprolactone-chitosan electrospun nanofibers as potential antimicrobial wound dressing

In this study, various concentrations of chrysin (chry) were loaded into polycaprolactone-chitosan (PCL-CTS) nanofibers to develop a potential wound dressing materials using electrospinning method. The structural composition and the morphology of the produced PCL-CTS5, PCL-CTS10 and PCL-CTS15 were analyzed by FE-SEM and FTIR, respectively. By increasing the amount of chry, the average diameter of the nanofibres was also increased to 191 ± 65 nm, 203 ± 72 nm, and 313 ± 69 nm for PCL-CTS5, PCL-CTS10, and PCL-CTS15, respectively. Moreover, the physicochemical characteristics and biological properties of synthesized nanofibers such as tensile testing, in-vitro drug release, porosity, decomposition rate, water absorption rate, water vapor permeability rate, cell viability, antioxidant and antibacterial activity were evaluated. By using Korsmeyer-Peppas and Higuchi kinetic models, the chry release mechanism in all nanofibers was studied in PBS solution, which suggested a Fick's diffusion. In-vitro antioxidant experiments by DPPH assay indicated 24, 43, 61 and 78 % free radical scavenging activity for PCL-CTS, PCL-CTS5, PCL-CTS10 and PCL-CTS15. In-vitro antibacterial examination showed that chry-loaded nanofibers had high antibacterial activity in which were comparable with the standard reagents. In-vitro cytotoxicity results obtained by MTT assay indicated a desired cytocompatibility towards fibroblast cells.

Bioactive Wound Healing 3D Structure Based on Chitosan Hydrogel Loaded with Naringin/Cyclodextrin Inclusion Nanocomplex

The current assay aimed to fabricate and analyze a potent wound healing structure based on a naringin (Nar)/β-cyclodextrin (β-CD)-loaded chitosan hydrogel. Using the simulation studies, we assessed the interactions among the Nar, β-CD, and the formation of the inclusion complex. Then, the formation of the hydrogel nanocomplex was simulated and evaluated using the in silico methods. The results showed that after optimization of the structures by DMol3 based on DFT-D, the total energies of Nar, GP, CD, and β-CD were calculated at -2100.159, -912.192, -3778.370, and -4273.078 Ha, respectively. The encapsulation energy of Nar on β-CD in the solvent phase was calculated at -93.626 kcal/mol, and the Nar structure was located inside β-CD in solution. The negative interaction energy value for the encapsulation of Nar on β-CD suggests the exothermic adsorption process and a stable structure between Nar and β-CD. Monte Carlo method was applied to obtain adsorption of CS/GP on Nar/β-CD. Its value of the obtained interaction energy was calculated at -1.423 × 103 kcal/mol. The characterization confirmed the formation of a Nar/β-CD inclusion complex. The Zeta potential of the pristine β-CD changed from -4.60 ± 1.1 to -17.60 ± 2.34 mV after interaction with Nar, and the heightened surface negativity can be attributed to the existence of electron-rich naringin molecules, as well as the orientation of the hydroxyl (OH) group of the β-CD toward the surface in an aqueous solution. The porosity of the fabricated hydrogels was in the range of 70-90% and during 14 days around 47.0 ± 3.1% of the pure hydrogel and around 56.4 ± 5.1 of hydrogel nanocomposite was degraded. The MTT assay showed that the hydrogels were biocompatible, and the wound contraction measurement (in an animal model) showed that the closure of the induced wound in the hydrogel nanocomposite treatment was faster than that of the control group (wound without treatment). The results of this study indicate that the developed bioactive wound healing 3D structure, which is composed of a chitosan hydrogel containing a Nar/β-CD inclusion nanocomplex, has potential as an effective material for wound dressing applications.

The One-Stop Integrated Nanoagent Based on Photothermal Therapy for Deep Infection Healing and Inflammation Inhibition

Chronic wounds caused by bacterial infections are a major challenge in medical fields. The hypoxia condition extremely induces reactive oxygen species (ROS) generation and upregulates the expression of hypoxia-inducible factor, both of which can increase the pro-inflammatory M1 subtype macrophages production while reducing the anti-inflammatory M2 subtype macrophages. Besides, bacteria-formed biofilms can hinder the penetration of therapeutic agents. Encouraged by natural motors automatically executing tasks, hypothesized that supplying sufficient oxygen (O2 ) would simultaneously drive therapeutic agent movement, rescue the hypoxic microenvironment, and disrupt the vicious cycle of inflammation. Here, small organic molecule-based nanoparticles (2TT-mC6B@Cu5.4 O NPs) that possess high photothermal conversion efficiency and enzymatic activities are developed, including superoxide dismutase-, catalase-, and glutathione peroxidase-like activity. 2TT-mC6B@Cu5.4 O NPs exhibit superior ROS-scavenging and O2 production abilities that synergistically relieve inflammation, alleviate hypoxia conditions, and promote their deep penetration in chronic wound tissues. Transcriptome analysis further demonstrates that 2TT-mC6B@Cu5.4O NPs inhibit biological activities inside bacteria. Furthermore, in vivo experiments prove that 2TT-mC6B@Cu5.4 O NPs-based hyperthermia can effectively eliminate bacteria in biofilms to promote wound healing.

In Vitro and Anti-Inflammatory Activity Evaluation Nanofibers from a Breath Mask and Filter Based on Polyurethane and Polyvinylidene Fluoride

Nanofiber (NF) products exhibit outstanding performances in materials science, textiles, and medicine that cannot be realized using conventional technologies. However, the safety of such products is debated because of the potential health risks that nanomaterials pose and the lack of standardized guidelines for the safety evaluation of NF products. The global safety evaluations of nanomaterials have focused on evaluating the cytotoxicity of low-dimensional materials, including nanoparticles and nanotubes, based on OECD (Organization for Economic Co-operation and Development) criteria. NFs are one-dimensional materials with nanometer diameters and considerable lengths. Many fibers are applied in a densely woven web-like form, so assessing cellular penetration and fiber toxicity using the same methods is inappropriate. This study verifies the safety of the polyurethane (PU) and polyvinylidene fluoride (PVDF) polymers currently applied in filters and masks. To this end, polymer NFs were collected from each product, and the NFs were compared with reference samples using FT-IR and Raman spectroscopy. For the safety evaluation, DMSO stocks of varying concentrations of PVDF and PU NFs (at 0.5, 1, 5, and 10 μg/mL) were prepared. The cytotoxicity and inhibitory effects on nitric oxide production and protein expression obtained via Western blot were identified.

Epidural Administration of Curcumin-Loaded Polycaprolactone/Gelatin Electrospun Nanofibers for Extended Analgesia After Laminectomy in Rats

Several clinical studies have reported the analgesic effect of curcumin (Curc) in various situations such as rheumatoid arthritis, osteoarthritis, and postsurgical pain. Therefore, in this work, Curc-loaded electrospun nanofibers (NFs) are designed to evaluate their sustained release on analgesic effect duration in rats after epidural placement via repeated formalin and tail-flick tests. The Curc-loaded polycaprolactone/gelatin NFs (Curc-PCL/GEL NFs) are prepared through an electrospinning technique and introduced to the rat's epidural space after laminectomy. The physicochemical and morphology features of the prepared Curc-PCL/GEL NFs were characterized via FE-SEM, FTIR, and degradation assay. The in vitro and in vivo concentrations of Curc were measured to evaluate the analgesic efficacy of the drug-loaded NFs. Rat nociceptive responses are investigated through repeated formalin and tail-flick tests for 5 weeks after the placement of NFs. Curc had a sustained release from the NFs for 5 weeks, and its local pharmaceutical concentrations were much greater than plasma concentrations. Rat's pain scores in both early and late phases of the formalin test were remarkably decreased in the experimental period. Rat's tail-flick latency was remarkably enhanced and remained constant for up to 4 weeks. Our findings show that the Curc-PCL/GEL NFs can supply controlled release of Curc to induce extended analgesia after laminectomy.

Implantable smart hyperthermia nanofibers for cancer therapy: Challenges and opportunities

Nanofibers (NFs) with practical drug-loading capacities, high stability, and controllable release have caught the attention of investigators due to their potential applications in on-demand drug delivery devices. Developing novel and efficient multidisciplinary management of locoregional cancer treatment through the design of smart NF-based systems integrated with combined chemotherapy and hyperthermia could provide stronger therapeutic advantages. On the other hand, implanting directly at the tumor area is a remarkable benefit of hyperthermia NF-based drug delivery approaches. Hence, implantable smart hyperthermia NFs might be very hopeful for tumor treatment in the future and provide new avenues for developing highly efficient localized drug delivery systems. Indeed, features of the smart NFs lead to the construction of a reversibly flexible nanostructure that enables hyperthermia and facile switchable release of antitumor agents to eradicate cancer cells. Accordingly, this study covers recent updates on applications of implantable smart hyperthermia NFs regarding their current scope and future outlook. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants.

NK cells direct the perspective approaches to cancer immunotherapy

Natural killer (NK) cells are innate immune cells with cytotoxic potentials to kill cancerous cells in several mechanisms, which could be implied for cancer therapy. While potent, their antitumor activities specially for solid tumors impaired by inadequate tumor infiltration, suppressive tumor microenvironment, cancer-associated stroma cells, and tumor-supportive immune cells. Therefore, manipulating or reprogramming these barriers by prospective strategies might improve current immunotherapies in the clinic or introduce novel NK-based immunotherapies. NK-based immunotherapy could be developed in monotherapy or in combination with other therapeutic regimens such as oncolytic virus therapy and immune checkpoint blockade, as presented in this review.

Long non-coding RNAs: The modulators of innate and adaptive immune cells

Before very sensitive current genomics platforms were discovered, long non-coding RNAs (lncRNAs) as controllers of gene expression, were thought to be accumulated genetic garbage. The past few years have seen a lot of interest in a large classification of non-coding transcripts with an indeterminate length of more than 200 nucleotides [1]. lncRNAs' association with immunity and disease progression has been revealed by a growing body of experimental research. Only a limited subset of lncRNAs, however, has solid proof of their role. It is also clear that various immune cells express lncRNAs differently. In this review, we concentrated on the role of lncRNA expression in the regulation of immune cell function and response to pathological conditions in macrophages, dendritic cells, natural killer (NK) cells, neutrophils, Myeloid-derived suppressor cells (MDSCs), T cells, and B cells. The innate and adaptive immune response systems may be significantly regulated by lncRNAs, according to emerging research. To discover possible therapeutic targets for the therapy of different diseases, it may be helpful to have a better realization of the molecular mechanisms beyond the role of lncRNAs in the immune response. Therefore, it is crucial to investigate lncRNA expression and comprehend its significance for the immune system.

Engineering Biomimetic Extracellular Matrix with Silica Nanofibers: From 1D Material to 3D Network

Biomaterials at nanoscale is a fast-expanding research field with which extensive studies have been conducted on understanding the interactions between cells and their surrounding microenvironments as well as intracellular communications. Among many kinds of nanoscale biomaterials, mesoporous fibrous structures are especially attractive as a promising approach to mimic the natural extracellular matrix (ECM) for cell and tissue research. Silica is a well-studied biocompatible, natural inorganic material that can be synthesized as morpho-genetically active scaffolds by various methods. This review compares silica nanofibers (SNFs) to other ECM materials such as hydrogel, polymers, and decellularized natural ECM, summarizes fabrication techniques for SNFs, and discusses different strategies of constructing ECM using SNFs. In addition, the latest progress on SNFs synthesis and biomimetic ECM substrates fabrication is summarized and highlighted. Lastly, we look at the wide use of SNF-based ECM scaffolds in biological applications, including stem cell regulation, tissue engineering, drug release, and environmental applications.

Electrospun fiber-based strategies for controlling early innate immune cell responses: Towards immunomodulatory mesh designs that facilitate robust tissue repair

Electrospun fibrous meshes are widely used for tissue repair due to their ability to guide a host of cell responses including phenotypic differentiation and tissue maturation. A critical factor determining the eventual biological outcomes of mesh-based regeneration strategies is the early innate immune response following implantation. The natural healing process involves a sequence of tightly regulated, temporally varying and delicately balanced pro-/anti-inflammatory events which together promote mesh integration with host tissue. Matrix designs that do not account for the immune milieu can result in dysregulation, chronic inflammation and fibrous capsule formation, thus obliterating potential therapeutic outcomes. In this review, we provide systematic insights into the effects of specific fiber/mesh properties and mechanical stimulation on the responses of early innate immune modulators viz., neutrophils, monocytes and macrophages. We identify matrix characteristics that promote anti-inflammatory immune phenotypes, and we correlate such responses with pro-regenerative in vivo outcomes. We also discuss recent advances in 3D fabrication technologies, bioactive functionalization approaches and biomimetic/bioinspired immunomodulatory mesh design strategies for tissue repair and wound healing. The mechanobiological insights and immunoregulatory strategies discussed herein can help improve the translational outcomes of fiber-based regeneration and may also be leveraged for intervention in degenerative diseases associated with dysfunctional immune responses. STATEMENT OF SIGNIFICANCE: The crucial role played by immune cells in promoting biomaterial-based tissue regeneration is being increasingly recognized. In this review focusing on the interactions of innate immune cells (primarily neutrophils, monocytes and macrophages) with electrospun fibrous meshes, we systematically elucidate the effects of the fiber microenvironment and mechanical stimulation on biological responses, and build upon these insights to inform the rational design of immunomodulatory meshes for effective tissue repair. We discuss state-of-the-art fabrication methods and mechanobiological advances that permit the orchestration of temporally controlled phenotypic switches in immune cells during different phases of healing. The design strategies discussed herein can also be leveraged to target several complex autoimmune and inflammatory diseases.

Anticancer efficacy of lupeol incorporated electrospun Polycaprolactone/gelatin nanocomposite nanofibrous mats

Despite the anticancer effect of lupeol (Lup), low aqueous solubility can make its therapeutic usage difficult. However, polycaprolactone/Gelatin (PCL-GEL) nanofibers scaffold eliminates this problem. This study has been conducted to recognize PCL-GEL-Lup nanofibers effect on cancer cell lines. PCL-GEL solution was prepared at different ratios (8 wt% and 4 wt%) for achieving optimal nanofibers. PCL-GEL-Lup nanofibers were provided via electrospinning technique. The surface morphology of nanofibers was examined using FESEM. Functional groups were investigated by a Fourier Transform Infrared spectroscopy. Lupeol released from nanofibers was detected by a UV-Visible spectroscopy. The drug release profile confirmed the sustained release of about 80% achieved within 40 h. IC₅₀of lupeol against ACHN and HSC-3 cell lines are 52.57 and 66.10μg ml^-1respectively. The study results from aid an understanding of the fabrication of a scaffold with an optimum dose of bioactive lupeol in 6 wt% with bead free uniform diameter that is capable of binding the drug efficiently. The enhanced cytotoxicity activity by effective diffusion and elution to the target achieved in this study help to develop a nanofiber in the ongoing battle against cancer.

Dual drug release mechanisms through mesoporous silica nanoparticle/electrospun nanofiber for enhanced anticancer efficiency of curcumin

Electrospun nanofibers (NFs)-based drug delivery approaches are of particular interest as a hopeful implantable nanoplatform for localized cancer therapy and treating tissue defect after resection, allowing the on-site drug delivery with minimal side effect to healthy cells. To maintain therapeutic concentrations of anticancer molecules for a relatively long time through a combination of burst and sustained drug release mechanisms, a hybrid of polycaprolactone and gelatin (PCL/GEL) was used for co-encapsulation of free curcumin (CUR) and CUR-loaded mesoporous silica nanoparticles (CUR@MSNs) via electrospinning, resulting in a novel drug-loaded nanofibrous scaffold, CUR/CUR@MSNs-NFs. The as-prepared MSNs and composite NFs were characterized via TGA, FTIR, FE-SEM, TEM, and BET. In vitro release profile of CUR from CUR/CUR@MSNs-NFs was examined, and the in vitro antitumor efficacy against MDA-MB-231 breast cancer cells was also evaluated through MTT, scratch assay, DAPI staining, and real-time PCR. The results disclosed that the smooth, bead-free, and randomly oriented CUR/CUR@MSNs-NFs displayed a combination of initial rapid discharge and sustained release for CUR, which led to higher cytotoxicity, lower migration as well as a more pronounced effect on apoptosis induction than CUR-NFs and CUR@MSNs-NFs. The present study illustrated that the dual drug release mechanisms through MSN/NF-mediated drug delivery systems might have a highly hopeful application as a localized implantable scaffold for potential postoperative breast cancer therapy.

Prolonged proliferation and delayed senescence of the adipose-derived stem cells grown on the electrospun composite nanofiber co-encapsulated with TiO2 nanoparticles and metformin-loaded mesoporous silica nanoparticles

This study was aimed to investigate the effects of the Poly-ε-Caprolactone/Gelatin nanofibers (PCL/GEL NFs) co-encapsulated with TiO₂ nanoparticles (nTiO₂) and metformin-loaded mesoporous silica nanoparticles (MET@MSNs) on prolonging the in vitro expansion of human adipose-derived stem cells (hADSCs) without inducing cellular senescence and aging. FTIR, BET, FE-SEM, and TEM were applied to characterize the fabricated MET@MSNs and electrospun composite NFs. The presence of inorganic particles, nTiO₂ and MSNs, in the scaffolds improved their mechanical properties and led to a more sustained release of MET with almost the lack of the initial burst release from nTiO₂/MET@MSNs-loaded NFs. The enhanced adhesion, metabolic activity, and proliferation rate of the hADSCs grown on nTiO₂/MET@MSNs-loaded NFs were demonstrated via FE-SEM images, MTT test and PicoGreen assay, respectively, over 28 days of culture. Furthermore, the irregular nanofibrillar structures and the impact of sustained release of MET led to a significant upregulation in the mRNA levels of autophagy (Atg-5, Atg-7, Atg-12, and Beclin-1) and stemness (Nanog3, Sox-2, and Oct-4) markers as well as a considerable down-regulation of p16^INK4A senescence marker. Further, the upregulation of hTERT, enhanced activity of telomerase, and increased telomere length were more pronounced in the hADSCs cultured on nTiO₂/MET@MSNs-loaded NFs as compared to other types of NFs. Overall, our findings demonstrated the potential of the fabricated nanocomposite platform for counteracting cellular senescence and achieving sufficient quantities of fresh hADSCs with preserved stemness for various stem cell-based regenerative medicine purposes.

Interleukin-4-loaded hydrogel scaffold regulates macrophages polarization to promote bone mesenchymal stem cells osteogenic differentiation via TGF-β1/Smad pathway for repair of bone defect

Objective

Tissue engineering is a promising strategy for repair of large bone defect. However, the immune system reactions to biological scaffold are increasingly being recognized as a crucial factor influencing regeneration efficacy. In this study, a bone‐bioactive hydrogel bead loaded with interleukin‐4 (IL‐4) was used to regulate macrophages polarization and accelerate bone regeneration.

Methods

IL‐4‐loaded calcium‐enriched gellan gum (Ca‐GG + IL‐4) hydrogel beads were synthesised. And the effect on cell behaviour was detected. Furthermore, the effect of the Ca‐GG + IL‐4 hydrogel bead on macrophage polarization and the effect of macrophage polarization on bone mesenchymal stem cells (BMSCs) apoptosis and osteogenic differentiation were evaluated in vitro and in vivo.

Results

BMSCs were able to survive in the hydrogel regardless of whether IL‐4 was incorporated. Immunofluorescence staining and qPCR results revealed that Ca‐GG + IL‐4 hydrogel bead could promote M2 macrophage polarization and increase transforming growth factor (TGF)‐β1 expression level, which activates the TGF‐β1/Smad signalling pathway in BMSCs and promotes osteogenic differentiation. Moreover, immunohistochemical analysis demonstrated Ca‐GG + IL‐4 hydrogel bead could promote M2 macrophage polarization and reduce cell apoptosis in vivo. In addition, micro‐CT and immunohistochemical analysis at 12 weeks post‐surgery showed that Ca‐GG + IL‐4 hydrogel bead could achieve superior bone defect repair efficacy in vivo.

Conclusions

The Ca‐GG + IL‐4 hydrogel bead effectively promoted bone defect regeneration via regulating macrophage polarization, reducing cell apoptosis and promoting BMSCs osteogenesis through TGF‐β1/Smad pathway. Therefore, it is a promising strategy for repair of bone defect.