Antiprotozoal activity of Boesenbergia rotunda (L.) Mansf and Ganoderma lucidum (Fr.) Kart extracts against Blastocystis hominis

Background and Aim: Blastocystis hominis is an intestinal protozoan in humans and animals. The parasite causes mild-to-severe intestinal complications, such as diarrhea, in healthy humans and immunocompromised hosts. This study aimed to determine the antiprotozoal activity of Boesenbergia rotunda (L.) Mansf and Ganoderma lucidum (Fr.) Kart extracts against B. hominis. Materials and Methods: Antiprotozoal activity of B. rotunda and G. lucidum extracts against B. hominis subtype 3 was determined using the erythrosin B exclusion assay, confirmed by a time-kill study. The morphology of the parasite treated with the extracts was observed by a scanning electron microscope. The phytochemicals present in B. rotunda and G. lucidum extracts were identified by gas chromatography-mass spectrometry analysis. Results: Both B. rotunda and G. lucidum extracts demonstrated strong antiprotozoal activity with similar minimum inhibitory concentration (MIC) values of 62.5 μg/mL. At 4× MIC and 8× MIC, both B. rotunda and G. lucidum extracts, and metronidazole inhibited the growth of B. hominis by up to 90% after 12 h treatment. Blastocystis hominis cells treated with B. rotunda extract, G. lucidum extract, and metronidazole were deformed and withered when compared with the control. Geraniol and versalide were found as the main compounds in B. rotunda and G. lucidum extracts, respectively. Conclusion: These results indicate the potential medicinal benefits of B. rotunda and G. lucidum extracts in the growth inhibition of B. hominis

Strong and tough nanofibrous hydrogel composites based on biomimetic principles

Mechanically robust hydrogels are required for many tissue engineering applications to serve as cell-supporting structures. Unlike natural tissues, the majority of existing tough hydrogels lack ordered microstructures organized to withstand specific loading conditions. In this work, electrospun gelatin nanofibres, mimicking the collagen network in native tissues, are used to strengthen and resist crack propagation in brittle alginate hydrogels. Aligned nanofibre reinforcement enhances the tensile strength of the hydrogels by up to two orders of magnitude. The nanofibres can be arranged as multilayer laminates with varying orientations, which increases the toughness by two orders of magnitude compared with the unreinforced hydrogel. This work demonstrates a two-part strategy of fibre reinforcement and composite lamination in manufacturing strong and tough hydrogels with flexible microstructures to suit different mechanical and biomedical requirements.K.T. acknowledges the Thai government and the University of Cambridge Nanoscience Doctoral Training Centre (EPSRC EP/G037221/1) for financial support, Anne Bahnweg for SEM assistance, Mark Rainer for electronics assistance, and Jenna Shapiro and Peerapat Thongnuek for helpful discussion. A.L.B. acknowledges the EPSRC Doctoral Training Account at Cambridge Engineering for financial support

Natural-based nanocomposites for bone tissue engineering and regenerative medicine: a review

Tissue engineering and regenerative medicine has been providing exciting technologies for the development of functional substitutes aimed to repair and regenerate damaged tissues and organs. Inspired by the hierarchical nature of bone, nanostructured biomaterials are gaining a singular attention for tissue engineering, owing their ability to promote cell adhesion and proliferation, and hence new bone growth, compared with conventional microsized materials. Of particular interest are nanocomposites involving biopolymeric matrices and bioactive nanosized fi llers. Biodegradability, high mechanical strength, and osteointegration and formation of ligamentous tissue are properties required for such materials. Biopolymers are advantageous due to their similarities with extracellular matrices, specifi c degradation rates, and good biological performance. By its turn, calcium phosphates possess favorable osteoconductivity, resorbability, and biocompatibility. Herein, an overview on the available natural polymer/calcium phosphate nanocomposite materials, their design, and properties is presented. Scaffolds, hydrogels, and fi bers as biomimetic strategies for tissue engineering, and processing methodologies are described. The specifi c biological properties of the nanocomposites, as well as their interaction with cells, including the use of bioactive molecules, are highlighted. Nanocomposites in vivo studies using animal models are also reviewed and discussed.  The research leading to this work has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS, and from QREN (ON.2 - NORTE-01-0124-FEDER-000016) cofinanced by North Portugal Regional Operational Program (ON.2 - O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF)

Composite electrospun gelatin fiber-alginate gel scaffolds for mechanically robust tissue engineered cornea

A severe shortage of good quality donor cornea is now an international crisis in public health. Alternatives for donor tissue need to be urgently developed to meet the increasing demand for corneal transplantation. Hydrogels have been widely used as scaffolds for corneal tissue regeneration due to their large water content, similar to that of native tissue. However, these hydrogel scaffolds lack the fibrous structure that functions as a load-bearing component in the native tissue, resulting in poor mechanical performance. This work shows that mechanical properties of compliant hydrogels can be substantially enhanced with electrospun nanofiber reinforcement. Electrospun gelatin nanofibers were infiltrated with alginate hydrogels, yielding transparent fiber-reinforced hydrogels. Without prior crosslinking, electrospun gelatin nanofibers improved the tensile elastic modulus of the hydrogels from 78±19. kPa to 450±100. kPa. Stiffer hydrogels, with elastic modulus of 820±210. kPa, were obtained by crosslinking the gelatin fibers with carbodiimide hydrochloride in ethanol before the infiltration process, but at the expense of transparency. The developed fiber-reinforced hydrogels show great promise as mechanically robust scaffolds for corneal tissue engineering applications. © 2013 Elsevier Ltd

Mechanical behaviour of electrospun fibre-reinforced hydrogels

Mechanically robust and biomimicking scaffolds are needed for structural engineering of tissues such as the intervertebral disc, which are prone to failure and incapable of natural healing. Here, the formation of thick, randomly aligned polycaprolactone electrospun fibre structures infiltrated with alginate is reported. The composites are characterised using both indentation and tensile testing and demonstrate substantially different tensile and compressive moduli. The composites are mechanically robust and exhibit large strains-to-failure, exhibiting toughening mechanisms observed in other composite material systems. The method presented here provides a way to create large-scale biomimetic scaffolds that more closely mimic the composite structure of natural tissue, with tuneable tensile and compressive properties via the fibre and matrix phases, respectively

Electrospun fiber - Hydrogel composites for nucleus pulposus tissue engineering

New materials are needed to replace degenerated intervertebral disc tissue and to provide longer-term solutions for chronic back-pain. Replacement tissue potentially could be engineered by seeding cells into a scaffold that mimics the architecture of natural tissue. Many natural tissues, including the nucleus pulposus (the central region of the intervertebral disc) consist of collagen nanofibers embedded in a gel-like matrix. Recently it was shown that electrospun micro- or nano-fiber structures of considerable thickness can be produced by collecting fibers in an ethanol bath. Here, randomly aligned polycaprolactone electrospun fiber structures up to 50 mm thick are backfilled with alginate hydrogels to form novel composite materials that mimic the fiber-reinforced structure of the nucleus pulposus. The composites are characterized using both indentation and tensile testing. The composites are mechanically robust, exhibiting substantial strain-to-failure. The method presented here provides a way to create large biomimetic scaffolds that more closely mimic the composite structure of natural tissue. © 2012 Materials Research Society

Time-dependent fracture toughness of cornea

The fracture and time-dependent properties of cornea are very important for the development of corneal scaffolds and prostheses. However, there has been no systematic study of cornea fracture; time-dependent behavior of cornea has never been investigated in a fracture context. In this work, fracture toughness of cornea was characterized by trouser tear tests, and time-dependent properties of cornea were examined by stress-relaxation and uniaxial tensile tests. Control experiments were performed on a photoelastic rubber sheet. Corneal fracture resistance was found to be strain-rate dependent, with values ranging from 3.39±0.57 to 5.40±0.48kJm-2 over strain rates from 3 to 300mmmin-1. Results from stress-relaxation tests confirmed that cornea is a nonlinear viscoelastic material. The cornea behaved closer to a viscous fluid at small strain but became relatively more elastic at larger strain. Although cornea properties are greatly dependent on time, the stress-strain responses of cornea were found to be insensitive to the strain rate when subjected to tensile loading. © 2014 Elsevier Ltd

Gelatin nanofiber-reinforced alginate gel scaffolds for corneal tissue engineering.

A severe shortage of donor cornea is now an international crisis in public health. Substitutes for donor tissue need to be developed to meet the increasing demand for corneal transplantation. Current attempts in designing scaffolds for corneal tissue regeneration involve utilization of expensive materials. Yet, these corneal scaffolds still lack the highly-organized fibrous structure that functions as a load-bearing component in the native tissue. This work shows that transparent nanofiber-reinforced hydrogels could be developed from cheap, non-immunogenic and readily available natural polymers to mimic the cornea's microstructure. Electrospinning was employed to produce gelatin nanofibers, which were then infiltrated with alginate hydrogels. Introducing electrospun nanofibers into hydrogels improved their mechanical properties by nearly one order of magnitude, yielding mechanically robust composites. Such nanofiber-reinforced hydrogels could serve as alternatives to donor tissue for corneal transplantation

Strong and tough nanofibrous hydrogel composites based on biomimetic principles

Mechanically robust hydrogels are required for many tissue engineering applications to serve as cell-supporting structures. Unlike natural tissues, the majority of existing tough hydrogels lack ordered microstructures organized to withstand specific loading conditions. In this work, electrospun gelatin nanofibres, mimicking the collagen network in native tissues, are used to strengthen and resist crack propagation in brittle alginate hydrogels. Aligned nanofibre reinforcement enhances the tensile strength of the hydrogels by up to two orders of magnitude. The nanofibres can be arranged as multilayer laminates with varying orientations, which increases the toughness by two orders of magnitude compared with the unreinforced hydrogel. This work demonstrates a two-part strategy of fibre reinforcement and composite lamination in manufacturing strong and tough hydrogels with flexible microstructures to suit different mechanical and biomedical requirements

Research data supporting “Strong and tough fibrous hydrogel composites based on biomimetic principles”

CSV file with data for figures 3, 5 and 6 in publication. Data from tensile and mode I and III toughness tests. Materials tested were hydrogels and fibre-reinforced hydrogels, including multi-layer laminates.EPSRC [1354760