Double hits with bioactive nanozyme based on cobalt-doped nanoglass for acute and diabetic wound therapies through anti-inflammatory and pro-angiogenic functions

Regeneration of pathological wounds, such as diabetic ulcers, poses a significant challenge in clinical settings, despite the widespread use of drugs. To overcome clinical side effects and complications, drug-free therapeutics need to be developed to promote angiogenesis while overcoming inflammation to restore regenerative events. This study presents a novel bioactive nanozyme based on cobalt-doped nanoglass (namely, CoNZ), which exhibits high enzymatic/catalytic activity while releasing therapeutic ions. Cobalt oxide "Co3O4" tiny crystallites produced in situ through a chemical reaction with H2O2 within CoNZ nanoparticles play a crucial role in scavenging ROS. Results showed that CoNZ-treatment to full-thickness skin wounds in mice significantly accelerated the healing process, promoting neovascularization, matrix deposition, and epithelial lining while reducing pro-inflammatory signs. Notably, CoNZ was highly effective in treating pathological wounds (streptozotocin-induced diabetic wounds). Rapid scavenging of ROS by CoNZ and down-regulation of pro-inflammatory markers while up-regulating tissue healing signs with proliferative cells and activated angiogenic factors contributed to the observed healing events. In vitro experiments involving CoNZ-cultures with macrophages and endothelial cells exposed to high glucose and ROS-generating conditions further confirmed the effectiveness of CoNZ. CoNZ-promoted angiogenesis was attributed to the release of cobalt ions, as evidenced by the comparable effects of CoNZ-extracted ionic medium in enhancing endothelial migration and tubule formation via activated HIF-1α. Finally, we compared the in vivo efficacy of CoNZ with the clinically-available drug deferoxamine. Results demonstrated that CoNZ was as effective as the drug in closing the diabetic wound, indicating the potential of CoNZ as a novel drug-free therapeutic approach.

Conducting polymer-based scaffolds for neuronal tissue engineering

Neuronal tissue engineering has immense potential for treating neurological disorders and facilitating nerve regeneration. Conducting polymers (CPs) have emerged as a promising class of materials owing to their unique electrical conductivity and biocompatibility. CPs, such as poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3-hexylthiophene) (P3HT), polypyrrole (PPy), and polyaniline (PANi), have been extensively explored for their ability to provide electrical cues to neural cells. These polymers are widely used in various forms, including porous scaffolds, hydrogels, and nanofibers, and offer an ideal platform for promoting cell adhesion, differentiation, and axonal outgrowth. CP-based scaffolds can also serve as drug delivery systems, enabling localized and controlled release of neurotrophic factors and therapeutic agents to enhance neural regeneration and repair. CP-based scaffolds have demonstrated improved neural regeneration, both in vitro and in vivo, for treating spinal cord and peripheral nerve injuries. In this review, we discuss synthesis and scaffold processing methods for CPs and their applications in neuronal tissue regeneration. We focused on a detailed literature review of the central and peripheral nervous systems.

Tubular nanomaterials for bone tissue engineering

Nanomaterial composition, morphology, and mechanical performance are critical parameters for tissue engineering. Within this rapidly expanding space, tubular nanomaterials (TNs), including carbon nanotubes (CNTs), titanium oxide nanotubes (TNTs), halloysite nanotubes (HNTs), silica nanotubes (SiNTs), and hydroxyapatite nanotubes (HANTs) have shown significant potential across a broad range of applications due to their high surface area, versatile surface chemistry, well-defined mechanical properties, excellent biocompatibility, and monodispersity. These include drug delivery vectors, imaging contrast agents, and scaffolds for bone tissue engineering. This review is centered on the recent developments in TN-based biomaterials for structural tissue engineering, with a strong focus on bone tissue regeneration. It includes a detailed literature review on TN-based orthopedic coatings for metallic implants and composite scaffolds to enhance in vivo bone regeneration.

Influence of Gelatin Source and Bloom Number on Gelatin Methacryloyl Hydrogels Mechanical and Biological Properties for Muscle Regeneration

Approximately half of an adult human's body weight is made up of muscles. Thus, restoring the functionality and aesthetics of lost muscle tissue is critical. The body is usually able to repair minor muscle injuries. However, when volumetric muscle loss occurs due to tumour extraction, for instance, the body will form fibrous tissue instead. Gelatin methacryloyl (GelMA) hydrogels have been applied for drug delivery, tissue adhesive, and various tissue engineering applications due to their tuneable mechanical properties. Here, we have synthesised GelMA from different gelatin sources (i.e., porcine, bovine, and fish) with varying bloom numbers, which refers to the gel strength, and investigated for the influence of the source of gelatin and the bloom number on biological activities and mechanical properties. The results indicated that the source of the gelatin and variable bloom numbers have an impact on GelMA hydrogel properties. Furthermore, our findings established that the bovine-derived gelatin methacryloyl (B-GelMA) has better mechanical properties than the other varieties composed of porcine and fish with 60 kPa, 40 kPa, and 10 kPa in bovine, porcine, and fish, respectively. Additionally, it showed a noticeably greater swelling ratio (SR) ~1100% and a reduced rate of degradation, improving the stability of hydrogels and giving cells adequate time to divide and proliferate to compensate for muscle loss. Furthermore, the bloom number of gelatin was also proven to influence the mechanical properties of GelMA. Interestingly, although GelMA made of fish had the lowest mechanical strength and gel stability, it demonstrated excellent biological properties. Overall, the results emphasise the importance of gelatin source and bloom number, allowing GelMA hydrogels to have a wide range of mechanical and excellent biological properties and making them suitable for various muscle tissue regeneration applications.

Chemically-induced osteogenic cells for bone tissue engineering and disease modeling

Cell reprogramming can satisfy the demands of obtaining specific cell types for applications such as tissue regeneration and disease modeling. Here we report the reprogramming of human fibroblasts to produce chemically-induced osteogenic cells (ciOG), and explore the potential uses of ciOG in bone repair and disease treatment. A chemical cocktail of RepSox, forskolin, and phenamil was used for osteogenic induction of fibroblasts by activation of RUNX2 expression. Following a maturation, the cells differentiated toward an osteoblast phenotype that produced mineralized nodules. Bulk and single-cell RNA sequencing identified a distinct ciOG population. ciOG formed mineralized tissue in an ectopic site of immunodeficiency mice, unlike the original fibroblasts. Osteogenic reprogramming was modulated under engineered culture substrates. When generated on a nanofiber substrate ciOG accelerated bone matrix formation in a calvarial defect, indicating that the engineered biomaterial promotes the osteogenic capacity of ciOG in vivo. Furthermore, the ciOG platform recapitulated the genetic bone diseases Proteus syndrome and osteogenesis imperfecta, allowing candidate drug testing. The reprogramming of human fibroblasts into osteogenic cells with a chemical cocktail thus provides a source of specialized cells for use in bone tissue engineering and disease modeling.

Submolecular Ligand Size and Spacing for Cell Adhesion

Cell adhesion occurs when integrin recognizes and binds to Arg-Gly-Asp (RGD) ligands present in fibronectin. In this work, submolecular ligand size and spacing are tuned via template-mediated in situ growth of nanoparticles for dynamic macrophage modulation. To tune liganded gold nanoparticle (GNP) size and spacing from 3 to 20 nm, in situ localized assemblies of GNP arrays on nanomagnetite templates are engineered. 3 nm-spaced ligands stimulate the binding of integrin, which mediates macrophage-adhesion-assisted pro-regenerative polarization as compared to 20 nm-spaced ligands, which can be dynamically anchored to the substrate for stabilizing integrin binding and facilitating dynamic macrophage adhesion. Increasing the ligand size from 7 to 20 nm only slightly promotes macrophage adhesion, not observed with 13 nm-sized ligands. Increasing the ligand spacing from 3 to 17 nm significantly hinders macrophage adhesion that induces inflammatory polarization. Submolecular tuning of ligand spacing can dominantly modulate host macrophages.

Harnessing the Therapeutic Potential of Extracellular Vesicles for Biomedical Applications Using Multifunctional Magnetic Nanomaterials

Extracellular vesicles (e.g., exosomes) carrying various biomolecules (e.g., proteins, lipids, and nucleic acids) have rapidly emerged as promising platforms for many biomedical applications. Despite their enormous potential, their heterogeneity in surfaces and sizes, the high complexity of cargo biomolecules, and the inefficient uptake by recipient cells remain critical barriers for their theranostic applications. To address these critical issues, multifunctional nanomaterials, such as magnetic nanomaterials, with their tunable physical, chemical, and biological properties, may play crucial roles in next-generation extracellular vesicles (EV)-based disease diagnosis, drug delivery, tissue engineering, and regenerative medicine. As such, one aims to provide cutting-edge knowledge pertaining to magnetic nanomaterials-facilitated isolation, detection, and delivery of extracellular vesicles and their associated biomolecules. By engaging the fields of extracellular vesicles and magnetic nanomaterials, it is envisioned that their properties can be effectively combined for optimal outcomes in biomedical applications.

Multifunctional GelMA platforms with nanomaterials for advanced tissue therapeutics

Polymeric hydrogels are fascinating platforms as 3D scaffolds for tissue repair and delivery systems of therapeutic molecules and cells. Among others, methacrylated gelatin (GelMA) has become a representative hydrogel formulation, finding various biomedical applications. Recent efforts on GelMA-based hydrogels have been devoted to combining them with bioactive and functional nanomaterials, aiming to provide enhanced physicochemical and biological properties to GelMA. The benefits of this approach are multiple: i) reinforcing mechanical properties, ii) modulating viscoelastic property to allow 3D printability of bio-inks, iii) rendering electrical/magnetic property to produce electro-/magneto-active hydrogels for the repair of specific tissues (e.g., muscle, nerve), iv) providing stimuli-responsiveness to actively deliver therapeutic molecules, and v) endowing therapeutic capacity in tissue repair process (e.g., antioxidant effects). The nanomaterial-combined GelMA systems have shown significantly enhanced and extraordinary behaviors in various tissues (bone, skin, cardiac, and nerve) that are rarely observable with GelMA. Here we systematically review these recent efforts in nanomaterials-combined GelMA hydrogels that are considered as next-generation multifunctional platforms for tissue therapeutics. The approaches used in GelMA can also apply to other existing polymeric hydrogel systems.

Estrogen-related Receptor Alpha (ERRα) is Required for PGC-1α-dependent Gene Expression in the Mouse Brain

Deficiency in peroxisome proliferator-activated receptor gamma coactivator 1-alpha. (PGC-1α) expression or function is implicated in numerous neurological and psychiatric disorders. PGC-1α is required for the expression of genes involved in synchronous neurotransmitter release, axonal integrity, and metabolism, especially in parvalbumin-positive interneurons. As a transcriptional coactivator, PGC-1α requires transcription factors to specify cell-type-specific gene programs; while much is known about these factors in peripheral tissues, it is unclear if PGC-1α utilizes these same factors in neurons. Here, we identified putative transcription factors controlling PGC-1α-dependent gene expression in the brain using bioinformatics and then validated the role of the top candidate in a knockout mouse model. We transcriptionally profiled cells overexpressing PGC-1α and searched for over-represented binding motifs in the promoters of upregulated genes. Binding sites of the estrogen-related receptor (ERR) family of transcription factors were enriched, and blockade of ERRα attenuated PGC-1α-mediated induction of mitochondrial and synaptic genes in cell culture. Localization in the mouse brain revealed enrichment of ERRα expression in parvalbumin-expressing neurons with tight correlation of expression with PGC-1α across brain regions. In ERRα null mice, PGC-1α-dependent genes were reduced in multiple regions, including neocortex, hippocampus, and cerebellum, though not to the extent observed in PGC-1α null mice. Behavioral assessment revealed ambulatory hyperactivity in response to amphetamine and impairments in sensorimotor gating without the overt motor impairment characteristic of PGC-1α null mice. These data suggest that ERRα is required for normal levels of expression of PGC-1α-dependent genes in neurons but that additional factors may be involved in their regulation.

A Study on Myogenesis by Regulation of Reactive Oxygen Species and Cytotoxic Activity by Selenium Nanoparticles

Reactive oxygen species (ROS) are continuously produced by skeletal muscle during contractile activity and even at rest. However, the ROS generated from excessive exercise or traumatic damage may produce more ROS than can be neutralized by an antioxidant capacity, which can be harmful to muscle function. In particular, selenium is a known antioxidant that regulates physiological functions such as cell differentiation and anti-inflammatory function. In this study, we developed nano-sized antioxidative biomaterials using selenium to investigate the protective and differentiation effects against C2C12 myoblasts in an H₂O₂-induced oxidative stress environment. The selenium nanoparticles (SeNPs) were produced with a size of 35.6 ± 4.3 nm and showed antioxidant effects according to the 3,3′,5,5′-tetramethylbenzidine assay. Then, SeNPs were treated to C2C12 cells with or without H₂O₂. Our results showed that SeNPs reduced C2C12 apoptosis and intracellular ROS levels. Additionally, SeNPs effectively up-regulated in the presence of H₂O₂, MyoD, MyoG, α-actinin, and myosin heavy chain, which are well known to increase during myoblast differentiation as assayed by qRT-PCR, immunocytochemistry-staining, western blotting. These results demonstrate that SeNPs can accelerate differentiation with its protective effects from the ROS environment and can be applied to the treatment of skeletal muscle in a cellular redox environment.

Magnetic Control and Real-Time Monitoring of Stem Cell Differentiation by the Ligand Nanoassembly

Native extracellular matrix (ECM) exhibits dynamic change in the ligand position. Herein, the ECM-emulating control and real-time monitoring of stem cell differentiation are demonstrated by ligand nanoassembly. The density of gold nanoassembly presenting cell-adhesive Arg-Gly-Asp (RGD) ligand on Fe₃ O₄ (magnetite) nanoparticle in nanostructures flexibly grafted to material is changed while keeping macroscale ligand density invariant. The ligand nanoassembly on the Fe₃ O₄ can be magnetically attracted to mediate rising and falling ligand movements via linker stretching and compression, respectively. High ligand nanoassembly density stimulates integrin ligation to activate the mechanosensing-assisted stem cell differentiation, which is monitored via in situ real-time electrochemical sensing. Magnetic control of rising and falling ligand movements hinders and promotes the adhesion-mediated mechanotransduction and differentiation of stem cells, respectively. These rising and falling ligand states yield the difference in the farthest distance (≈34.6 nm) of the RGD from material surface, thereby dynamically mimicking static long and short flexible linkers, which hinder and promote cell adhesion, respectively. Design of cytocompatible ligand nanoassemblies can be made with combinations of dimensions, shapes, and biomimetic ligands for remotely regulating stem cells for offering novel methodologies to advance regenerative therapies.

Advances in Engineered Polymer Nanoparticle Tracking Platforms towards Cancer Immunotherapy-Current Status and Future Perspectives

Engineering polymeric nanoparticles for their shape, size, surface chemistry, and functionalization using various targeting molecules has shown improved biomedical applications for nanoparticles. Polymeric nanoparticles have created tremendous therapeutic platforms, particularly applications related to chemo- and immunotherapies in cancer. Recently advancements in immunotherapies have broadened this field in immunology and biomedical engineering, where "immunoengineering" creates solutions to target translational science. In this regard, the nanoengineering field has offered the various techniques necessary to manufacture and assemble multifunctional polymeric nanomaterial systems. These include nanoparticles functionalized using antibodies, small molecule ligands, targeted peptides, proteins, and other novel agents that trigger and encourage biological systems to accept the engineered materials as immune enhancers or as vaccines to elevate therapeutic functions. Strategies to engineer polymeric nanoparticles with therapeutic and targeting molecules can provide solutions for developing immune vaccines via maintaining the receptor storage in T- and B cells. Furthermore, cancer immunotherapy using polymeric nanomaterials can serve as a gold standard approach for treating primary and metastasized tumors. The current status of the limited availability of immuno-therapeutic drugs highlights the importance of polymeric nanomaterial platforms to improve the outcomes via delivering anticancer agents at localized sites, thereby enhancing the host immune response in cancer therapy. This review mainly focuses on the potential scientific enhancements and recent developments in cancer immunotherapies by explicitly discussing the role of polymeric nanocarriers as nano-vaccines. We also briefly discuss the role of multifunctional nanomaterials for their therapeutic impacts on translational clinical applications.

Selenium Nanoparticles as Candidates for Antibacterial Substitutes and Supplements against Multidrug-Resistant Bacteria

In recent years, multidrug-resistant (MDR) bacteria have increased rapidly, representing a major threat to human health. This problem has created an urgent need to identify alternatives for the treatment of MDR bacteria. The aim of this study was to identify the antibacterial activity of selenium nanoparticles (SeNPs) and selenium nanowires (SeNWs) against MDR bacteria and assess the potential synergistic effects when combined with a conventional antibiotic (linezolid). SeNPs and SeNWs were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), zeta potential, and UV-visible analysis. The antibacterial effects of SeNPs and SeNWs were confirmed by the macro-dilution minimum inhibitory concentration (MIC) test. SeNPs showed MIC values against methicillin-sensitive S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), vancomycin-resistant S. aureus (VRSA), and vancomycin-resistant enterococci (VRE) at concentrations of 20, 80, 320, and >320 μg/mL, respectively. On the other hand, SeNWs showed a MIC value of >320 μg/mL against all tested bacteria. Therefore, MSSA, MRSA, and VRSA were selected for the bacteria to be tested, and SeNPs were selected as the antimicrobial agent for the following experiments. In the time-kill assay, SeNPs at a concentration of 4X MIC (80 and 320 μg/mL) showed bactericidal effects against MSSA and MRSA, respectively. At a concentration of 2X MIC (40 and 160 μg/mL), SeNPs showed bacteriostatic effects against MSSA and bactericidal effects against MRSA, respectively. In the synergy test, SeNPs showed a synergistic effect with linezolid (LZD) through protein degradation against MSSA and MRSA. In conclusion, these results suggest that SeNPs can be candidates for antibacterial substitutes and supplements against MDR bacteria for topical use, such as dressings. However, for use in clinical situations, additional experiments such as toxicity and synergistic mechanism tests of SeNPs are needed.

The eggshell membrane: A potential biomaterial for corneal wound healing

The eggshell membrane (ESM) is an abundant resource with innate complex structure and composition provided by nature. With at least 60 million tonnes of hen eggs produced globally per annum, utilisation of this waste resource is highly attractive in positively impacting sustainability worldwide. Given the morphology and mechanical properties of this membrane, it has great potential as a biomaterials for wound dressing. However, to date, no studies have demonstrated nor reported this application. As such, the objective of this investigation was to identify and optimise a reproducible extraction protocol of the ESM and to assess the physical, chemical, mechanical and biological properties of the substrate with a view to use as a wound dressing. ESM samples were isolated by either manual peeling (ESM-strip) or via extraction using acetic acid [ESM-A0.5] or ethylenediaminetetraacetic acid, EDTA [ESM-E0.9]. Energy dispersive X-ray spectroscopy (EDS) confirmed that there were no traces of calcium residues from the extraction process. Fourier transform infrared (FTIR) spectroscopy revealed that the extraction method (acetic acid and EDTA) did not alter the chemical structures of the ESM and also clarified the composition of the fibrous proteins of the ESM. Scanning electron microscopy (SEM) analyses revealed a three-layer composite structure of the ESM: an inner layer as continuous, dense and non-fibrous (limiting membrane), a middle layer with a network of fibres (inner shell membrane) and the outer layer (outer shell membrane) of larger fibres. Material properties including optical transparency, porosity, fluid absorption/uptake, thermal stability, mechanical profiling of the ESM samples were performed and demonstrated suitable profiles for translational applications. Biological in vitro studies using SV40 immortalised corneal epithelial cells (ihCEC) and corneal mesenchymal stromal cells (C-MSC) demonstrated excellent biocompatibility. Taken together, these results document the development of a novel sustainable biomaterial that may be used for ophthalmic wounds and/or other biomedical therapies.

Three dimensional porous scaffolds derived from collagen, elastin and fibrin proteins orchestrate adipose tissue regeneration

Current gold standard to treat soft tissue injuries caused by trauma and pathological condition are autografts and off the shelf fillers, but they have inherent weaknesses like donor site morbidity, immuno-compatibility and graft failure. To overcome these limitations, tissue-engineered polymers are seeded with stem cells to improve the potential to restore tissue function. However, their interaction with native tissue is poorly understood so far. To study these interactions and improve outcomes, we have fabricated scaffolds from natural polymers (collagen, fibrin and elastin) by custom-designed processes and their material properties such as surface morphology, swelling, wettability and chemical cross-linking ability were characterised. By using 3D scaffolds, we comprehensive assessed survival, proliferation and phenotype of adipose-derived stem cells in vitro. In vivo, scaffolds were seeded with adipose-derived stem cells and implanted in a rodent model, with X-ray microtomography, histology and immunohistochemistry as read-outs. Collagen-based materials showed higher cell adhesion and proliferation in vitro as well as higher adipogenic properties in vivo. In contrast, fibrin demonstrated poor cellular and adipogenesis properties but higher angiogenesis. Elastin formed the most porous scaffold, with cells displaying a non-aggregated morphology in vitro while in vivo elastin was the most degraded scaffold. These findings of how polymers present in the natural polymers mimicking ECM and seeded with stem cells affect adipogenesis in vitro and in vivo can open avenues to design 3D grafts for soft tissue repair.

Utilization of GelMA with phosphate glass fibers for glial cell alignment

Glial cell alignment in tissue engineered constructs is essential for achieving functional outcomes in neural recovery. While gelatin methacrylate (GelMA) hydrogel offers superior biocompatibility along with permissive structure and tailorable mechanical properties, phosphate glass fibers (PGFs) can provide physical cues for directionality of neural growth. Aligned PGFs were fabricated by a melt quenching and fiber drawing method and utilized with synthesized GelMA hydrogel. The mechanical properties of GelMA and biocompatibility of the GelMA-PGFs composite were investigated in vitro using rat glial cells. GelMA with 86% methacrylation degree were photo-crosslinked using 0.1%wt photo-initiator (PI). Photocrosslinking under UV exposure for 60 s was used to produce hydrogels (GelMA-60). PGFs were introduced into the GelMA before crosslinking. Storage modulus and loss modulus of GelMA-60 was 24.73 ± 2.52 and 1.08 ± 0.23 kN/m² , respectively. Increased cell alignment was observed in GelMA-PGFs compared with GelMA hydrogel alone. These findings suggest GelMA-PGFs can provide glial cells with physical cues necessary to achieve cell alignment. This approach could further be used to achieve glial cell alignment in bioengineered constructs designed to bridge damaged nerve tissue.

Comparative study of photoinitiators for the synthesis and 3D printing of a light-curable, degradable polymer for custom-fit hard tissue implants

Three-dimensional (3D) printing enhances the production of on-demand fabrication of patient-specific devices, as well as anatomically fitting implants with high complexity in a cost-effective manner. Additive systems that employ vat photopolymerisation such as stereolithography (SLA) and digital light projection are used widely in the field of biomedical science and engineering. However, additive manufacturing methods can be limited by the types of materials that can be used. In this study, we present an isosorbide-based formulation for a polymer resin yielding a range of elastic moduli between 1.7 and 3 GN mm^-2 dependent on the photoinitiator system used as well as the amount of calcium phosphate filler added. The monomer was prepared and enhanced for 3D-printing using an SLA technique that delivered stable and optimized 3D-printed models. The resin discussed could potentially be used following major surgery for the correction of congenital defects, the removal of oral tumours and the reconstruction of the head and neck region. The surgeon is usually limited with devices available to restore both function and appearance and with the ever-increasing demand for low-priced and efficient facial implants, there is an urgent need to advance new manufacturing approaches and implants with a higher osseointegration performance.

Flexible paper based piezo-resistive sensor functionalised by 2D-WSe2 nanosheets

High-performance electronics demand extremely sensitive piezo-resistive sensors with important features such as low-fabrication cost, easy implementation, low power consumption and high-pressure sensitivity over broad pressure range. Herein, we report a flexible piezo-resistive paper-based device functionalised by WSe₂ nanosheets. An efficient and low-cost fabrication strategy using Whatman filter paper and tissue paper is adopted for versatile sensing applications. The WSe₂ nanosheets were synthesized by high-yield and size-controlled liquid phase exfoliation technique. The flexible WSe₂ nanosheets-paper sensor shows excellent response in broad pressure range of 1 Pa-100 kPa with exceptionally high sensitivity of 29.24 kPa^-1, current responsivity of 70 and response time of 100 ms. The pressure sensor is also employed to recognize the pressure generated due to finger tapping. Encouragingly, the piezo-resistive sensors can also sense extremely small pressure differences of about 1.4 Pa generated by water drops.

Coating biopolymer nanofibers with carbon nanotubes accelerates tissue healing and bone regeneration through orchestrated cell- and tissue-regulatory responses

Tailoring the surface of biomaterial scaffolds has been a key strategy to modulate the cellular interactions that are helpful for tissue healing process. In particular, nanotopological surfaces have been demonstrated to regulate diverse behaviors of stem cells, such as initial adhesion, spreading and lineage specification. Here, we tailor the surface of biopolymer nanofibers with carbon nanotubes (CNTs) to create a unique bi-modal nanoscale topography (500 nm nanofiber with 25 nm nanotubes) and report the performance in modulating diverse in vivo responses including inflammation, angiogenesis, and bone regeneration. When administered to a rat subcutaneous site, the CNT-coated nanofiber exhibited significantly reduced inflammatory signs (down-regulated pro-inflammatory cytokines and macrophages gathering). Moreover, the CNT-coated nanofibers showed substantially promoted angiogenic responses, with enhanced neoblood vessel formation and angiogenic marker expression. Such stimulated tissue healing events by the CNT interfacing were evidenced in a calvarium bone defect model. The in vivo bone regeneration of the CNT- coated nanofibers was significantly accelerated, with higher bone mineral density and up-regulated osteogenic signs (OPN, OCN, BMP2) of in vivo bone forming cells. The in vitro studies using MSCs could demonstrate accelerated adhesion and osteogenic differentiation and mineralization, supporting the osteo-promoting mechanism behind the in vivo bone forming event. These findings highlight that the CNTs interfacing of biopolymer nanofibers is highly effective in reducing inflammation, promoting angiogenesis, and driving adhesion and osteogenesis of MSCs, which eventually orchestrate to accelerate tissue healing and bone regeneration process. STATEMENT OF SIGNIFICANCE: Here we demonstrate that the interfacing of biopolymer nanofibers with carbon nanotubes (CNTs) could modulate multiple interactions of cells and tissues that are ultimately helpful for the tissue healing and bone regeneration process. The CNT-coated scaffolds significantly reduced the pro-inflammatory signals while stimulating the angiogenic marker expressions. Furthermore, the CNT-coated scaffolds increased the bone matrix production of bone forming cells in vivo as well as accelerated the adhesion and osteogenic differentiation of MSCs in vitro. These collective findings highlight that the CNTs coated on the biopolymer nanofibers allow the creation of a promising platform for nanoscale engineering of biomaterial surface that can favor tissue healing and bone regeneration process, through a series of orchestrated events in anti-inflammation, pro-angiogenesis, and stem cell stimulation.

Carbon nanotube incorporation in PMMA to prevent microbial adhesion

Although PMMA-based biomaterials are widely used in clinics, a major hurdle, namely, their poor antimicrobial (i.e., adhesion) properties, remains and can accelerate infections. In this study, carboxylated multiwalled carbon nanotubes (CNTs) were incorporated into poly(methyl methacrylate) (PMMA) to achieve drug-free antimicrobial adhesion properties. After characterizing the mechanical/surface properties, the anti-adhesive effects against 3 different oral microbial species (Staphylococcus aureus, Streptococcus mutans, and Candida albicans) were determined for roughened and highly polished surfaces using metabolic activity assays and staining for recognizing adherent cells. Carboxylated multiwalled CNTs were fabricated and incorporated into PMMA. Total fracture work was enhanced for composites containing 1 and 2% CNTs, while other mechanical properties were gradually compromised with the increase in the amount of CNTs incorporated. However, the surface roughness and water contact angle increased with increasing CNT incorporation. Significant anti-adhesive effects (35~95%) against 3 different oral microbial species without cytotoxicity to oral keratinocytes were observed for the 1% CNT group compared to the PMMA control group, which was confirmed by microorganism staining. The anti-adhesive mechanism was revealed as a disconnection of sequential microbe chains. The drug-free antimicrobial adhesion properties observed in the CNT-PMMA composite suggest the potential utility of CNT composites as future antimicrobial biomaterials for preventing microbial-induced complications in clinical settings (i.e., Candidiasis).

Combinatory Cancer Therapeutics with Nanoceria-Capped Mesoporous Silica Nanocarriers through pH-triggered Drug Release and Redox Activity

In the field of nanomedicine, drug-loaded nanocarriers that integrate nanotechnology and chemotherapeutics are widely used to achieve synergistic therapeutic effects. Here, we prepared mesoporous silica nanoparticles capped with cerium oxide nanoparticles (COP@MSN) wherein a pH trigger-responsive mechanism was used to control drug release and intracellular drug delivery. We blocked the mesopores of the carboxyl-functionalized MSN with aminated COP. These pores could be opened in acidic conditions to release the loaded drug, thus establishing a pH-responsive drug release system. We loaded doxorubicin (DOX) as anticancer biomolecule into the pores of MSN and capped with COP. The COP@DOX-MSN system showed a typical drug release profile in an acidic medium, which, however, was not observed in a neutral medium. In vitro studies using cancer cell line (HeLa) proved that the COP@DOX-MSN entered efficiently into HeLa cells and released DOX to the level sufficient for cytotoxicity. The cytotoxic effect of COP in cancer cells was facilitated by the pro-oxidant property of COPs, which considerably raised the reactive oxygen species (ROS) level, thereby leading to cellular apoptosis. The combination of DOX with COP (COP@DOX-MSN) showed even higher ROS level, demonstrating a cytotoxic synergism of drug and nanoparticle in terms of ROS generation. Collectively, the COP@DOX-MSN is considered useful for cancer treatment with the combined capacity of pH-controlled drug delivery, chemotherapeutics, and redox activity.

Nanohybrid Electro-Coatings Toward Therapeutic Implants with Controlled Drug Delivery Potential for Bone Regeneration

Coatings of metallic implants facilitate a new bioactive interface that favors osteogenic responses and bone formation. Providing a therapeutic capacity to the coatings, involving with a sustainable and controllable delivery of drug molecules, significantly improves the bone regenerative potential. Here we design a novel nanocomposite coating, made of mesoporous silica-shelled hydroxyapatite (MS-HA) nanoparticles and chitosan (Chi), incorporating osteogenic drug dexamethasone phosphate (Dex(P)) within the MS-HA, by the process of an electrophoretic deposition (EPD). MS-HA, produced by a sol–gel reaction of silica onto an HA nanorod, exhibited mono-dispersed core–shell nanoparticles with a size of ∼40 nm and a shell thickness of ∼25 nm. The highly mesoporous structure enabled an effective loading of Dex(P) onto the nanocarriers, showing a loading capacity as high as 15% by weight. The Dex(P) loaded MS-HA were homogenized with Chi in acidic ethanol/water to allow for the EPD process. Nanocomposite coatings were produced well, forming thicknesses a few micrometers largely tunable with EPD parameters and exhibiting MS-HA nanoparticles evenly distributed within Chi matrix. While Dex(P) release from the bare MS-HA nanocarrier was very abrupt, showing a complete release within 24 h, the Dex(P) release from the nanocomposite coatings profiled a highly sustainable pattern over a month. Rat mesenchymal stem cells cultured on the Dex(P)-releasing coatings were substantially stimulated to an osteoblastic lineage, presenting enhanced alkaline phosphate activity and higher levels of osteogenic genes, with respect to coatings free of Dex(P). An indirect culture test also confirmed the long-term release effects of Dex(P) from the coatings over 4 weeks. The currently-developed nanocomposite EPD coatings, with a capacity to load osteogenic drug at large quantity and to deliver for a long-term period, are considered as a promising therapeutic coating platform for metallic bone implants.

Silk fibroin/collagen protein hybrid cell-encapsulating hydrogels with tunable gelation and improved physical and biological properties

Cell encapsulating hydrogels with tunable mechanical and biological properties are of special importance for cell delivery and tissue engineering. Silk fibroin and collagen, two typical important biological proteins, are considered potential as cell culture hydrogels. However, both have been used individually, with limited properties (e.g., collagen has poor mechanical properties and cell-mediated shrinkage, and silk fibroin from Bombyx mori (mulberry) lacks cell adhesion motifs). Therefore, the combination of them is considered to achieve improved mechanical and biological properties with respect to individual hydrogels. Here, we show that the cell-encapsulating hydrogels of mulberry silk fibroin / collagen are implementable over a wide range of compositions, enabled simply by combining the different gelation mechanisms. Not only the gelation reaction but also the structural characteristics, consequently, the mechanical properties and cellular behaviors are accelerated significantly by the silk fibroin / collagen hybrid hydrogel approach. Of note, the mechanical and biological properties are tunable to represent the combined merits of individual proteins. The shear storage modulus is tailored to range from 0.1 to 20 kPa along the iso-compositional line, which is considered to cover the matrix stiffness of soft-to-hard tissues. In particular, the silk fibroin / collagen hydrogels are highly elastic, exhibiting excellent resistance to permanent deformation under different modes of stress; without being collapsed or water-squeezed out (vs. not possible in individual proteins) - which results from the mechanical synergism of interpenetrating networks of both proteins. Furthermore, the role of collagen protein component in the hybrid hydrogels provides adhesive sites to cells, stimulating anchorage and spreading significantly with respect to mulberry silk fibroin gel, which lacks cell adhesion motifs. The silk fibroin / collagen hydrogels can encapsulate cells while preserving the viability and growth over a long 3D culture period. Our findings demonstrate that the silk / collagen hydrogels possess physical and biological properties tunable and significantly improved (vs. the individual protein gels), implying their potential uses for cell delivery and tissue engineering.

STATEMENT OF SIGNIFICANCE

Development of cell encapsulating hydrogels with excellent physical and biological properties is important for the cell delivery and cell-based tissue engineering. Here we communicate for the first time the novel protein composite hydrogels comprised of 'Silk' and 'Collagen' and report their outstanding physical, mechanical and biological properties that are not readily achievable with individual protein hydrogels. The properties include i) gelation accelerated over a wide range of compositions, ii) stiffness levels covering 0.1 kPa to 20 kPa that mimic those of soft-to-hard tissues, iii) excellent elastic behaviors under various stress modes (bending, twisting, stretching, and compression), iv) high resistance to cell-mediated gel contraction, v) rapid anchorage and spreading of cells, and vi) cell encapsulation ability with a long-term survivability. These results come from the synergism of individual proteins of alpha-helix and beta-sheet structured networks. We consider the current elastic cell-encapsulating hydrogels of silk-collagen can be potentially useful for the cell delivery and tissue engineering in a wide spectrum of soft-to-hard tissues.

Optical imaging and anticancer chemotherapy through carbon dot created hollow mesoporous silica nanoparticles

Multifunctional nanocarrier-based theranostics is currently considered to solve some key unmet challenges in cancer treatment. Here we report a nanocarrier platform, named carbon dot (CD) created mesoporous hollow organosilica (C-hMOS) nanoparticles, to deliver anticancer drug and to enable optical imaging. The hollow structure was formed by the removal of a nanorod core template, and at the same time, the fluorescent signal was endowed from the heat-treated organosilica network. Thanks to the hollow and mesoporous structure, the C-hMOS effectively loaded doxorubicin (DOX) for cancer chemotherapy. The DOX was released from C-hMOS highly sustainably (over 12days) and pH-dependently (pH 5.0 >pH 7.4). The DOX-loading C-hMOS internalized cancer cells efficiently (>90%), and induced cellular apoptosis including the expression of caspase-3. The treatment of C-hMOS to cancer cells enabled multi-color visualization in vitro, suggesting the possibility of cell tracing. Moreover, when injected intratumorally in mice, the C-hMOS exhibited strong optical signals in vivo along with a high optical stability (over a week). The injected C-hMOS were distributed only a fraction in liver but not in heart, lung, spleen or kidney and displayed good biocompatibility. The DOX-delivering C-hMOS significantly suppressed the in vivo tumor growth associated with apoptotic functions. Taken together, the developed C-hMOS nanoparticles can be a promising nanoplatform for drug delivery and in vivo imaging in cancer treatment.

STATEMENT OF SIGNIFICANCE

Multifunctional nanoparticles that combine chemotherapeutic ability with imaging modality comprise promising platform for cancer theranostics. Here we developed a novel theranostic nanoparticle, i.e., carbon-dot created mesoporous hollow silica nanoparticle, to offer unique merit for this purpose. The in vitro and in vivo findings to support this include: i) carbon dots with 1-2nm size in situ generated discretely and uniformly within silica network, ii) hollow and mesoporous structure effective for loading of DOX at high content, iii) release behavior of DOX in a sustainable and pH-dependent manner, iv) chemotherapeutic efficacy in killing cancer cells and suppressing tumor growth through DOX delivery, and v) carbon dot induced multi-color fluorescence imaging within cells and tumor tissues. These collective multifaceted properties may facilitate the novel carbon dot nanocarriers to be a potential candidate for delivering anticancer drug and non-invasive imaging in cancer treatment.

Progress in Nanotheranostics Based on Mesoporous Silica Nanomaterial Platforms

Theranostics based on nanoparticles (NPs) is a promising paradigm in nanomedicine. Mesoporous silica nanoparticle (MSN)-based systems offer unique characteristics to enable multimodal imaging or simultaneous diagnosis and therapy. They include large surface area and volume, tunable pore size, functionalizable surface, and acceptable biological safety. Hybridization with other NPs and chemical modification can further potentiate the multifunctionality of MSN-based systems toward translation. Here, we update the recent progress on MSN-based systems for theranostic purposes. We discuss various synthetic approaches used to construct the theranostic platforms either via intrinsic chemistry or extrinsic combination. These include defect generation in the silica structure, encapsulation of diagnostic NPs within silica, their assembly on the silica surface, and direct conjugation of dye chemicals. Collectively, in vitro and in vivo results demonstrate that multimodal imaging capacities can be integrated with the therapeutic functions of these MSN systems for therapy. With further improvement in bioimaging sensitivity and targeting specificity, the multifunctional MSN-based theranostic systems will find many clinical applications in the near future.

Novel Epoxy Resin—Part 2

A novel epoxy resin, namely diglycidyl ether (DGE) of 2,4-dihydroxyacetophenone (i.e. resacetophenone, RAP) was prepared and characterized. The curing of DGE–RAP by various diamines was studied kinetically by differential scanning calorimetry (DSC). The cured neat products have been characterized by IR spectral studies and thermogravimetric analysis (TGA). The glass-reinforced composites based on such a novel epoxy resin–diamine system have also been prepared and characterized.

Osteopromoting Reservoir of Stem Cells: Bioactive Mesoporous Nanocarrier/Collagen Gel through Slow-Releasing FGF18 and the Activated BMP Signaling

Providing an osteogenic stimulatory environment is a key strategy to construct stem cell-based bone-equivalent tissues. Here we design a stem cell delivering gel matrix made of collagen (Col) with bioactive glass nanocarriers (BGn) that incorporate osteogenic signaling molecule, fibroblast growth factor 18 (FGF18), a reservoir considered to cultivate and promote osteogenesis of mesenchymal stem cells (MSCs). The presence of BGn in the gel was shown to enhance the osteogenic differentiation of MSCs, possibly due to the therapeutic role of ions released. The mesoporous nature of BGn was effective in loading FGF18 at large quantity, and the FGF18 release from the BGn-Col gel matrix was highly sustainable with almost a zero-order kinetics, over 4 weeks as confirmed by the green fluorescence protein signal change. The released FGF18 was effective in accelerating osteogenesis (alkaline phosphatase activity and bone related gene expressions) and bone matrix formation (osteopontin, bone sialoprotein, and osteocalcin production) of MSCs. This was attributed to the bone morphogenetic protein (BMP) signaling pathway, where the FGF18 release stimulated the endogenous secretion of BMP2 and the downstream signal Smad1/5/8. Taken together, the FGF18-BGn/Col gel is considered an excellent osteopromoting depot to support and signal MSCs for bone tissue engineering.

C-Dot Generated Bioactive Organosilica Nanospheres in Theranostics: Multicolor Luminescent and Photothermal Properties Combined with Drug Delivery Capacity

Biocompatible nanomaterials that allow for labeling cells and tissues with the capacity to load and deliver drug molecules hold great promise for the therapeutic-diagnostic purposes in tissue repair and disease cure. Here a novel nanoplatform, called C-dot bioactive organosilica nanosphere (C-BON), is introduced to have excellent theranostic potential, such as controlled drug delivery, visible-light imaging, and NIR photothermal activity. C-dots with a few nanometers were in situ generated in the Ca-containing organosilica mesoporous nanospheres through the sol-gel and thermal-treatment processes. The C-BON exhibited multicolor luminescence over a wide visible-light range with strong emissions and high photostability over time and against acidity and the possible in vivo optical imaging capacity when injected in rat subcutaneous tissues. Moreover, the C-BON showed a photothermal heating effect upon the irradiation of near-infrared. The C-BON, thanks to the high mesoporosity and existence of Ca(2+) ions, demonstrated excellent loading capacity of anticancer drug doxorubicin (as high as 90% of carrier weight) and long-term (over a couple of weeks) and pH/NIR-dependent release ability. The C-BON preserved the compositional merit of Ca-Si glass, having excellent bioactivity and cell compatibility in vitro. Taken all, the multifunctional properties of C-BON-multicolor luminescence, photothermal activity, and high drug loading and controlled release-together with its excellent bioactivity and cell compatibility potentiate the future applications in theranostics (chemotherapy and photothermal therapy with optical imaging).

Biocompatible Mesoporous Nanotubular Structured Surface to Control Cell Behaviors and Deliver Bioactive Molecules

Biocompatible nanostructured surfaces control the cell behaviors and tissue integration process of medical devices and implants. Here we develop a novel biocompatible nanostructured surface based on mesoporous silica nanotube (MSNT) by means of an electrodeposition. MSNTs, replicated from carbon nanotubes of 25 nm × 1200 nm size, were interfaced in combination with fugitive biopolymers (chitosan or collagen) onto a Ti metallic substrate. The MSNT-biopolymer deposits uniformly covered the substrate with weight gains controllable by the electrodeposition conditions. Random nanotubular networks were generated successfully, which alongside the high mesoporosity provided unique nanotopological properties for the cell responses and the loading/delivery of biomolecules. Of note, the adhesion and spreading behaviors of mesenchymal stem cells (MSCs) were significantly altered, revealing more rapid cell anchorage and extensive nanofilopodia development along the nanotubular networks. Furthermore, the nanotubular surface improved the loading capacity of biomolecules (dexamethasone and bovine serum albumin) up to 5-7 times. The release of the biomolecules was highly sustained, exhibiting a diffusion-controlled pattern over 15 days. The therapeutic efficacy of the delivered biomolecules was also confirmed in the osteogenic differentiation of MSCs. While in vivo performance and applicability studies are needed further, the current biocompatible nanostructured surface may be considered as a novel biointerfacing platform to control cellular behaviors and biomolecular delivery.

Smart multifunctional drug delivery towards anticancer therapy harmonized in mesoporous nanoparticles

Nanomedicine seeks to apply nanoscale materials for the therapy and diagnosis of diseased and damaged tissues. Recent advances in nanotechnology have made a major contribution to the development of multifunctional nanomaterials, which represents a paradigm shift from single purpose to multipurpose materials. Multifunctional nanomaterials have been proposed to enable simultaneous target imaging and on-demand delivery of therapeutic agents only to the specific site. Most advanced systems are also responsive to internal or external stimuli. This approach is particularly important for highly potent drugs (e.g. chemotherapeutics), which should be delivered in a discreet manner and interact with cells/tissues only locally. Both advances in imaging and precisely controlled and localized delivery are critically important in cancer treatment, and the use of such systems - theranostics - holds great promise to minimise side effects and boost therapeutic effectiveness of the treatment. Among others, mesoporous silica nanoparticles (MSNPs) are considered one of the most promising nanomaterials for drug delivery. Due to their unique intrinsic features, including tunable porosity and size, large surface area, structural diversity, easily modifiable chemistry and suitability for functionalization, and biocompatibility, MSNPs have been extensively utilized as multifunctional nanocarrier systems. The combination or hybridization with biomolecules, drugs, and other nanoparticles potentiated the ability of MSNPs towards multifunctionality, and even smart actions stimulated by specified signals, including pH, optical signal, redox reaction, electricity and magnetism. This paper provides a comprehensive review of the state-of-the-art of multifunctional, smart drug delivery systems centered on advanced MSNPs, with special emphasis on cancer related applications.

Mesoporous silica-layered biopolymer hybrid nanofibrous scaffold: a novel nanobiomatrix platform for therapeutics delivery and bone regeneration

Nanoscale scaffolds that characterize high bioactivity and the ability to deliver biomolecules provide a 3D microenvironment that controls and stimulates desired cellular responses and subsequent tissue reaction. Herein novel nanofibrous hybrid scaffolds of polycaprolactone shelled with mesoporous silica (PCL@MS) were developed. In this hybrid system, the silica shell provides an active biointerface, while the 3D nanoscale fibrous structure provides cell-stimulating matrix cues suitable for bone regeneration. The electrospun PCL nanofibers were coated with MS at controlled thicknesses via a sol-gel approach. The MS shell improved surface wettability and ionic reactions, involving substantial formation of bone-like mineral apatite in body-simulated medium. The MS-layered hybrid nanofibers showed a significant improvement in mechanical properties, in terms of both tensile strength and elastic modulus, as well as in nanomechanical surface behavior, which is favorable for hard tissue repair. Attachment, growth, and proliferation of rat mesenchymal stem cells were significantly improved on the hybrid scaffolds, and their osteogenic differentiation and subsequent mineralization were highly up-regulated by the hybrid scaffolds. Furthermore, the mesoporous surface of the hybrid scaffolds enabled the loading of a series of bioactive molecules, including small drugs and proteins at high levels. The release of these molecules was sustainable over a long-term period, indicating the capability of the hybrid scaffolds to deliver therapeutic molecules. Taken together, the multifunctional hybrid nanofibrous scaffolds are considered to be promising therapeutic platforms for stimulating stem cells and for the repair and regeneration of bone.

Novel magnetic nanocomposite injectables: calcium phosphate cements impregnated with ultrafine magnetic nanoparticles for bone regeneration

Novel magnetic nanocomposite injectables made of calcium phosphate cements and magnetite nanoparticles demonstrated excellent physico-chemical and biological properties effective for bone regeneration.

Nanostructured biointerfacing of metals with carbon nanotube/chitosan hybrids by electrodeposition for cell stimulation and therapeutics delivery

Exploring the biological interfaces of metallic implants has been an important issue in achieving biofunctional success. Here we develop a biointerface with nanotopological features and bioactive composition, comprising a carbon nanotube (CNT) and chitosan (Chi) hybrid, via an electrophoretic deposition (EPD). The physicochemical properties, in vitro biocompatibility, and protein delivering capacity of the decorated nanohybrid layer were investigated, to address its potential usefulness as bone regenerating implants. Over a wide compositional range, the nanostructured hybrid interfaces were successfully formed with varying thicknesses, depending on the electrodeposition parameters. CNT-Chi hybrid interfaces showed a time-sequenced degradation in saline water, and a rapid induction of hydroxyapatite mineral in a simulated body fluid. The nanostructured hybrid substrates stimulated the initial adhesion events of the osteoblastic cells, including cell adhesion rate, spreading behaviors, and expression of adhesive proteins. The nanostructured hybrid interfaces significantly improved the adsorption of protein molecules, which was enabled by the surface charge interaction, and increased surface area of the nanotopology. Furthermore, the incorporated protein was released at a highly sustained rate, profiling a diffusion-controlled pattern over a couple of weeks, suggesting the possible usefulness as a protein delivery device. Collectively, the nanostructured hybrid CNT-Chi layer, implemented by an electrodeposition, is considered a biocompatible, cell-stimulating, and protein-delivering biointerface of metallic implants.

Potential of magnetic nanofiber scaffolds with mechanical and biological properties applicable for bone regeneration

Magnetic nanofibrous scaffolds of poly(caprolactone) (PCL) incorporating magnetic nanoparticles (MNP) were produced, and their effects on physico-chemical, mechanical and biological properties were extensively addressed to find efficacy for bone regeneration purpose. MNPs 12 nm in diameter were citrated and evenly distributed in PCL solutions up to 20% and then were electrospun into nonwoven nanofibrous webs. Incorporation of MNPs greatly improved the hydrophilicity of the nanofibers. Tensile mechanical properties of the nanofibers (tensile strength, yield strength, elastic modulus and elongation) were significantly enhanced with the addition of MNPs up to 15%. In particular, the tensile strength increase was as high as ∼25 MPa at 15% MNPs vs. ∼10 MPa in pure PCL. PCL-MNP nanofibers exhibited magnetic behaviors, with a high saturation point and hysteresis loop area, which increased gradually with MNP content. The incorporation of MNPs substantially increased the degradation of the nanofibers, with a weight loss of ∼20% in pure PCL, ∼45% in 10% MNPs and ∼60% in 20% MNPs. Apatite forming ability of the nanofibers tested in vitro in simulated body fluid confirmed the substantial improvement gained by the addition of MNPs. Osteoblastic cells favored the MNPs-incorporated nanofibers with significantly improved initial cell adhesion and subsequent penetration through the nanofibers, compared to pure PCL. Alkaline phosphatase activity and expression of genes associated with bone (collagen I, osteopontin and bone sialoprotein) were significantly up-regulated in cells cultured on PCL-MNP nanofibers than those on pure PCL. PCL-MNP nanofibers subcutaneously implanted in rats exhibited minimal adverse tissue reactions, while inducing substantial neoblood vessel formation, which however, greatly limited in pure PCL. In vivo study in radial segmental defects also signified the bone regeneration ability of the PCL-MNP nanofibrous scaffolds. The magnetic, bone-bioactive, mechanical, cellular and tissue attributes of MNP-incorporated PCL nanofibers make them promising candidate scaffolds for bone regeneration.

A novel therapeutic design of microporous-structured biopolymer scaffolds for drug loading and delivery

Three-dimensional (3-D) open-channeled scaffolds of biopolymers are a promising candidate matrix for tissue engineering. When scaffolds have the capacity to deliver bioactive molecules the potential for tissue regeneration should be greatly enhanced. In order to improve drug-delivery capacity, we exploit 3-D poly(lactic acid) (PLA) scaffolds by creating microporosity within the scaffold network. Macroporous channeled PLA with a controlled pore configuration was obtained by a robotic dispensing technique. In particular, a room temperature ionic liquid (RTIL) bearing hydrophilic counter-anions, such as OTf and Cl, was introduced to the biopolymer solution at varying ratios. The RTIL-biopolymer slurry was homogenized by ultrasonication, and then solidified through the robotic dispensing process, during which the biopolymer and RTIL formed a bicontinuous interpenetrating network. After ethanol wash-out treatment the RTIL was completely removed to leave highly microporous open channels throughout the PLA network. The resultant pore size was observed to be a few micrometers (average 2.43 μm) and microporosity was determined to be ∼ 70%. The microporous surface was also shown to favor initial cell adhesion, stimulating cell anchorage on the microporous structure. Furthermore, in vivo tissue responses assessed in rat subcutaneous tissue revealed good tissue compatibility, with minimal inflammatory reactions, while gathering a larger population of fibroblastic cells than the non-microporous scaffolds, and even facilitating invasion of the cells within the microporous structure. The efficacy of the micropore networks generated within the 3-D scaffolds in loading and releasing therapeutic molecules was addressed using antibiotic sodium ampicillin and protein cytochrome C as model drugs. The microporous scaffolds exhibited significantly enhanced drug loading capacity: 4-5 times increase in ampicillin and 9-10 times increase in cytochrome C compared to the non-microporous scaffolds. The release of ampicillin loaded within the microporous scaffolds was initially fast (∼ 85% for 1 week), and was then slowed down, showing a continual release up to a month. On the other hand, cytochrome C was shown to release in a highly sustainable manner over a month, without showing an initial burst release effect. This study provides a novel insight into the generation of 3-D biopolymer scaffolds with high performance in loading and delivery of biomolecules, facilitated by the creation of microporous channels through the scaffold network. The capacity to support tissue cells while in situ delivering drug molecules makes the current scaffolds potentially useful for therapeutic tissue engineering.

Luminescent mesoporous nanoreservoirs for the effective loading and intracellular delivery of therapeutic drugs

Development of biocompatible and multifunctional nanocarriers is important for the therapeutic efficacy of drug molecules in the treatment of disease and tissue repair. A novel nanocarrier of luminescent hollowed mesoporous silica (L-hMS) was explored for the loading and controlled delivery of drugs. For the synthesis of L-hMS, self-activated luminescence hydroxyapatite (LHA) was used as a template. Different thicknesses (∼ 7-62 nm) of mesoporous silica shell were obtained by varying the volume of silica precursor and the subsequent removal of the LHA core, which resulted in hollow-cored (size of ∼ 40 nm × 10 nm) mesoporous silica nanoreservoirs, L-hMS. While the silica shell provided a highly mesoporous structure, enabling an effective loading of drug molecules, the luminescent property of LHA was also well preserved in both the silica-shelled and the hollow-cored nanocarriers. Doxorubicin (DOX), used as a model drug, was shown to be effectively loaded onto the mesopore structure and within the hollow space of the nanoreservoir. The DOX release was fairly pH-dependent, occurring more rapidly at pH 5.3 than at pH 7.4, and a long-term sustainable delivery over the test period of 2weeks was observed. The nanoreservoir exhibited favorable cell compatibility with low cytotoxicity and excellent cell uptake efficiency (over 90%). Treatment of HeLa cells with DOX-loaded L-hMS elicited a sufficient degree of biological efficacy of DOX, as confirmed in the DOX-induced apoptotic behaviors, including stimulation in caspase-3 expression, and was even more effective than the direct DOX treatment. Overall, the newly developed L-hMS nanoreservoirs may be potentially useful as a multifunctional (luminescent, mesoporous and biocompatible) carrier system to effectively load and sustainably deliver small molecules, including anticancer drugs.

Multifunctional hybrid nanocarrier: magnetic CNTs ensheathed with mesoporous silica for drug delivery and imaging system

Here we communicate the development of a novel multifunctional hybrid nanomaterial, magnetic carbon nanotubes (CNTs) ensheathed with mesoporous silica, for the simultaneous applications of drug delivery and imaging. Magnetic nanoparticles (MNPs) were first decorated onto the multiwalled CNTs, which was then layered with mesoporous silica (mSiO2) to facilitate the loading of bioactive molecules to a large quantity while exerting magnetic properties. The hybrid nanomaterial showed a high mesoporosity due to the surface-layered mSiO2, and excellent magnetic properties, including magnetic resonance imaging in vitro and in vivo. The mesoporous and magnetic hybrid nanocarriers showed high loading capacity for therapeutic molecules including drug gentamicin and protein cytochrome C. In particular, genetic molecule siRNA was effectively loaded and then released over a period of days to a week. Furthermore, the hybrid nanocarriers exhibited a high cell uptake rate through magnetism, while eliciting favorable biological efficacy within the cells. This novel hybrid multifunctional nanocarrier may be potentially applicable as drug delivery and imaging systems.

Polymeric nanoparticle formulation of octapeptide (NP-OP): in vitro release and in vivo effect in common marmosets, Callithrix jacchus Linn

Octapeptide (OP)/FSH-Receptor Binding Inhibitor-8 (FRBI-8), is a synthetic peptide corresponding to N-terminal sequence of purified fraction of Follicle Stimulating Hormone Binding-Inhibitor (FSHBI), isolated earlier from human ovarian follicular-fluid. In order to avoid the repeated drug-administration, OP-loaded, polymeric polylactide (PLA) nanoparticle formulation (NP-OP), was developed using multiple-emulsion technique. This yielded an average particle size of 120 nm with 70% encapsulation-efficiency. In vitro release profile of NP-OP showed sustained release of OP for 21 days. In vivo anti-fertility studies were conducted in marmosets. Results indicated that control animals conceived in the same cycle while two of three treated animals failed to conceive in treatment cycle. The in vivo studies thus corroborate with in vitro release of OP, demonstrating its anti-fertility activity in 66% of animals.

Electronic structure investigation of MoS2 and MoSe2 using angle-resolved photoemission spectroscopy and ab initio band structure studies

Angle-resolved photoemission spectroscopy (ARPES) and ab initio band structure calculations have been used to study the detailed valence band structure of molybdenite, MoS(2) and MoSe(2). The experimental band structure obtained from ARPES has been found to be in good agreement with the theoretical calculations performed using the linear augmented plane wave (LAPW) method. In going from MoS(2) to MoSe(2), the dispersion of the valence bands decreases along both k(parallel) and k(perpendicular), revealing the increased two-dimensional character which is attributed to the increasing interlayer distance or c/a ratio in these compounds. The width of the valence band and the band gap are also found to decrease, whereas the valence band maxima shift towards the higher binding energy from MoS(2) to MoSe(2).

Biocompatible magnetite nanoparticles with varying silica-coating layer for use in biomedicine: physicochemical and magnetic properties, and cellular compatibility

Magnetic nanoparticles (MNPs) are considered highly useful in therapeutic and diagnostic applications. However, MNPs require surface modification to promote dispersibility in aqueous solutions and thus biocompatibility. In this article, the authors modified MNPs with inorganic silica layer to create silica-coated magnetite nanoparticles (MNP@Si) via sol-gel process. Synthesis involves hydrolysis and condensation steps using tetraethylorthosilicate (TEOS) in methanol/ polyethylene glycol (PEG) solution and ammonia catalyst. Nanoparticles were characterized in terms of morphology, particle size, crystalline phase, chemical-bond structure, surface charge and magnetic properties: in particular, the MNP@Si size was easily tunable through alteration of the Fe(3) O(4) -to-TEOS ratio. As this ratio increased, the MNP@Si size decreased from 270 to 15 nm whilst maintaining core 12-nm MNP particle size, indicating decrease in thickness of the silica coating. All MNP@Si, in direct contrast to uncoated MNPs, showed excellent stability in aqueous solution. The particles' physicochemical and magnetic properties systematically varied with size (coating thickness), and the zeta potential diminished toward negative values, while magnetization increased as the coating thickness decreased. 15-nm MNP@Si showed excellent magnetization (about 64.1 emu/g), almost comparable to that of uncoated MNPs (70.8 emu/g). Preliminary in vitro assays confirmed that the silica layer significantly reduced cellular toxicity as assessed by increase in cell viability and reduction in reactive oxygen species production during 48 h of culture. Newly-developed MNP@Si, with a high capacity for magnetization, water-dispersibility, and diminished cell toxicity, may be potentially useful in diverse biomedical applications, including delivery of therapeutic and diagnostic biomolecules.

Inhibiting fatty acid amide hydrolase normalizes endotoxin-induced enhanced gastrointestinal motility in mice

BACKGROUND AND PURPOSE

Gastrointestinal (GI) motility is regulated in part by fatty acid ethanolamides (FAEs), including the endocannabinoid (EC) anandamide (AEA). The actions of FAEs are terminated by fatty acid amide hydrolase (FAAH). We investigated the actions of the novel FAAH inhibitor AM3506 on normal and enhanced GI motility.

EXPERIMENTAL APPROACH

We examined the effect of AM3506 on electrically-evoked contractility in vitro and GI transit and colonic faecal output in vivo, in normal and FAAH-deficient mice treated with saline or LPS (100 µg·kg(-1), i.p.), in the presence and absence of cannabinoid (CB) receptor antagonists. mRNA expression was measured by quantitative real time-PCR, EC levels by liquid chromatography-MS and FAAH activity by the conversion of [(3)H]-AEA to [(3)H]-ethanolamine in intestinal extracts. FAAH expression was examined by immunohistochemistry.

KEY RESULTS

FAAH was dominantly expressed in the enteric nervous system; its mRNA levels were higher in the ileum than the colon. LPS enhanced ileal contractility in the absence of overt inflammation. AM3506 reversed the enhanced electrically-evoked contractions of the ileum through CB(1) and CB(2) receptors. LPS increased the rate of upper GI transit and faecal output. AM3506 normalized the enhanced GI transit through CB(1) and CB(2) receptors and faecal output through CB(1) receptors. LPS did not increase GI transit in FAAH-deficient mice.

CONCLUSIONS AND IMPLICATIONS

Inhibiting FAAH normalizes various parameters of GI dysmotility in intestinal pathophysiology. Inhibition of FAAH represents a new approach to the treatment of disordered intestinal motility.

Shear-dependent eosinophil transmigration on interleukin 4-stimulated endothelial cells: a role for endothelium-associated eotaxin-3

Leukocyte infiltration into inflammatory sites is regulated by the expression of adhesion and activation proteins, yet the role of these proteins in shear-dependent transmigration is poorly understood. We examined eosinophil recruitment on cytokine-stimulated human umbilical vein endothelial cells (HUVECs) under laminar flow conditions. Eosinophils rapidly transmigrated on interleukin (IL)-4-, but not TNF-stimulated HUVECs. Transmigration was shear dependent, with up to 90% of eosinophils transmigrating in the presence of shear and less than 25% of cells transmigrating under static conditions. Eosinophils express CC chemokine receptor CCR3 and are responsive to various CC chemokines. The effects of chemokines are mediated primarily through G(alpha)i, which is pertussis toxin sensitive. Greater than 65% of shear-dependent eosinophil transmigration on IL-4-stimulated HUVECs was blocked by either pertussis toxin or by an anti-CCR3 monoclonal antibody. Using reverse transcription polymerase chain reaction (RT-PCR) and Western blots, we found that IL-4-stimulated HUVECs produce both mRNA and protein for eotaxin-3. Eotaxin-3 was both released by HUVECs and expressed on the endothelial cell surface. Pretreatment of HUVECs with an anti-eotaxin-3 antibody blocked eosinophil transmigration to the same extent as an anti-CCR3 antibody. These results indicate that IL-4-stimulated HUVECs support shear-dependent eosinophil transmigration by upregulating eotaxin-3, and that surface association is critical for the role of eotaxin-3 in transmigration.

Exclusive neutrophil recruitment with oncostatin M in a human system

Oncostatin M (OSM), a member of the IL-6 family has been postulated to be a potent recruiter of leukocytes, however information regarding the molecular mechanism(s) underlying this event is extremely limited. Therefore, the aim of this study was to investigate the role of OSM-mediated leukocyte recruitment in a human system in vitro under flow conditions. A parallel-plate flow chamber assay was used to examine leukocyte recruitment from whole blood by human umbilical vein endothelium treated for 24 hours with OSM. OSM in a dose-response manner revealed very significant leukocyte rolling and adhesion reaching optimal levels at a very low concentration of OSM (10 ng/ml). The OSM-induced leukocyte rolling and adhesion was comparable to levels seen with tumor necrosis factor. OSM was extremely selective for neutrophil recruitment (96%) with <3% lymphocyte recruitment. By contrast, tumor necrosis factor-alpha revealed no such selectivity, recruiting 70% neutrophils and at least 25% lymphocytes and detectable levels of eosinophils at 24 hours. The molecular mechanism underlying the leukocyte recruitment seemed to be entirely dependent on P-selectin as leukocyte recruitment could be completely blocked by the addition of a P-selectin-blocking antibody. An elevation in both P-selectin message and protein was observed with 24 hours of OSM stimulation of endothelium. By contrast, E-selectin and VCAM-1 were not detectable after OSM stimulation. Similar results were seen with passaged dermal microvascular endothelium that does not have a prestored pool of P-selectin. Based on these results, we conclude that OSM may be a very selective potent recruiter of neutrophils in more prolonged inflammatory conditions, an event exclusively dependent on P-selectin.

Papillary cystadenocarcinoma arising in a paratubal mesothelial cyst of the mesosalpinx--a case report

Primary carcinoma arising from a paratubal cyst in the mesosalpinx in uncommon. Serous tumors of low malignant potential outnumber invasive carcinomas, which are often of endometrioid type. Only five cases of serous papillary cystadenocarcinoma with capsular invasion have been documented. We report a case of invasive papillary cystadenocarcinoma arising in a large paratubal cyst of the mesosalpinx, in an infertile woman. Possible hormonal basis, its link to serous borderline and malignant tumors of the peritoneum, and value of pre/intra operative cyst fluid cytology are discussed. Lack of definitive management protocols, prognostic indicators and possible consequences are briefly reviewed.