Ilida Ortega Asencio
@sheffield.ac.uk
The School of Clinical Dentistry
The University of Sheffield
RESEARCH, TEACHING, or OTHER INTERESTS
Biomaterials, Bioengineering, Classics
Scopus Publications
Scopus Publications
Selina Beal, Iain Stewart, Paul Hatton, Marysia Placzek, and Ilida Ortega
Elsevier BV
Betül Aldemir Dikici, Atra Malayeri, Colin Sherborne, Serkan Dikici, Thomas Paterson, Lindsey Dew, Paul Hatton, Ilida Ortega Asencio, Sheila MacNeil, Caitlin Langford,et al.
American Chemical Society (ACS)
Highly porous emulsion templated polymers (PolyHIPEs) provide a number of potential advantages in the fabrication of scaffolds for tissue engineering and regenerative medicine. Porosity enables cell ingrowth and nutrient diffusion within, as well as waste removal from, the scaffold. The properties offered by emulsion templating alone include the provision of high interconnected porosity, and, in combination with additive manufacturing, the opportunity to introduce controlled multiscale porosity to complex or custom structures. However, the majority of monomer systems reported for PolyHIPE preparation are unsuitable for clinical applications as they are nondegradable. Thiol-ene chemistry is a promising route to produce biodegradable photocurable PolyHIPEs for the fabrication of scaffolds using conventional or additive manufacturing methods; however, relatively little research has been reported on this approach. This study reports the groundwork to fabricate thiol- and polycaprolactone (PCL)-based PolyHIPE materials via a photoinitiated thiolene click reaction. Two different formulations, either three-arm PCL methacrylate (3PCLMA) or four-arm PCL methacrylate (4PCLMA) moieties, were used in the PolyHIPE formulation. Biocompatibility of the PolyHIPEs was investigated using human dermal fibroblasts (HDFs) and human osteosarcoma cell line (MG-63) by DNA quantification assay, and developed PolyHIPEs were shown to be capable of supporting cell attachment and viability.
Hatim Alqurashi, Ilida Ortega Asencio, and Daniel W. Lambert
Mary Ann Liebert Inc
Extracellular vesicles are membrane-enclosed vesicles secreted by all cell types that mediate cell:cell communication via their protein, lipid, carbohydrate and nucleic acid (RNA, DNA) cargo. EVs are involved in a multitude of physiological processes including development, cell differentiation and angiogenesis, and have been implicated in tissue repair. Thus, they have been suggested to offer opportunities for the development of novel cell-free tissue engineering approaches. In this review, we provide an overview of current understanding and emerging applications of EVs in tissue engineering and address opportunities and challenges for clinical translation. In addition, we discuss systemic and local routes of delivery of EVs and the advantages and disadvantages of different biomaterials in providing a substrate for the sustained release of EVs in vivo.
Charanya Ramachandran, Pallavi Deshpande, Ilida Ortega, Farshid Sefat, Rob McKean, Mala Srivastava, Sheila MacNeil, Sayan Basu, and Virender Singh Sangwan
BMJ
ObjectiveThe aim of this study was to assess the safety of poly-lactic co-glycolic acid (PLGA) electrospun membranes as carriers for limbal tissue explants for treatment of limbal stem cell deficiency (LSCD).Methods and analysisApproval was obtained for a first in-man study from the Drug Controller General of India. PLGA membranes were applied to the affected eye of five patients after removal of the vascular pannus. Simple limbal epithelial transplantation was performed and limbal explants were secured on the membrane using fibrin glue followed by a bandage contact lens. Patients were followed up for 1 year with ocular exams including slit lamp exam, corneal thickness measurements, intraocular pressure measurements and recording of corneal vascularisation and visual acuity. Systemic examinations included pain grading, clinical laboratory assessment, blood chemistry and urine analysis at baseline, 3 and 6 months after surgery.ResultsPLGA membranes completely degraded by 8 weeks post-transplantation without any infection or inflammation. In all five patients, the epithelium regenerated by 3 months. In two in five patients, there was a sustained two-line improvement in vision. In one in five patients, the vision improvement was limited due to an underlying stromal scarring. There was recurrence of pannus and LSCD in two in five patients 6 months after surgery which was not attributable to the membrane. The ocular surface remained clear with no epithelial defects in three in five subjects at 12 months.ConclusionPLGA electrospun membranes show promise as carrier for limbal epithelial cells in the treatment of LSCD.
Thomas E. Paterson, Hala S. Dhowre, Danilo Villanueva, Joseph W. Holland, Abhinav Reddy Kethiri, Vivek Singh, Frederik Claeyssens, Sheila MacNeil, and Ilida Ortega Asencio
American Chemical Society (ACS)
Corneal blindness is the fourth most common cause of vision impairment worldwide with a high incidence in global south countries. A recently developed surgical technique for treating corneal blindness is simple limbal epithelial transplantation (SLET), which uses small pieces of healthy limbal tissue (limbal explants) delivered to the damaged eye using the human amniotic membrane (AM) as a carrier. SLET relies on the use of tissue banks for the AM that reduces the availability of the technique. Replacing the AM with a synthetic membrane is key to making SLET more accessible to those who need it. Previous research has demonstrated the suitability of electrospun poly(lactide-co-glycolide) (PLGA) scaffolds as AM substitutes, and here, we report how these membranes can be tailored to mimic fundamental AM mechanical properties. To modify the stiffness of PLGA electrospun membranes, we explored different electrospinning solvent systems (1,1,1,3,3,3,-hexafluoroisopropanol (HFIP), dichloromethane (DCM), chloroform, and N,N-dimethylformamide (DMF)) and the use of plasticizers (PEG400 and glycerol). PEG400 was found to reduce stiffness from 60 MPa to around 4 MPa, approaching the values shown by the native AM. The biocompatibility of membranes with and without PEG400 was found to be comparable, and cell outgrowth from rabbit/porcine explants was successfully observed on the materials after 3 weeks. This research underpins the manufacture of next-generation fibrous biomimetic membranes that will ultimately be used as amniotic membrane substitutes for biomedical applications including SLET.
David H. Ramos-Rodriguez, Sheila MacNeil, Frederik Claeyssens, and Ilida Ortega Asencio
American Chemical Society (ACS)
The use of microfabrication techniques for the development of innovative constructs for tissue regeneration is a growing area of research. This area comprises both manufacturing and biological approaches for the development of smart materials aiming to control and direct cell behavior to enhance tissue healing. Many groups have focused their efforts on introducing complexity within these innovative constructs via the inclusion of nano- and microtopographical cues mimicking physical and biological aspects of the native stem cell niche. Specifically, in the area of skin tissue engineering, seminal work has reported replicating the microenvironments located in the dermal-epithelial junction, which are known as rete ridges. The rete ridges are key for both stem cell control and the physiological performance of the skin. In this work, we have introduced complexity within electrospun membranes to mimic the morphology of the rete ridges in the skin. We designed and tested three different patterns, characterized them, and explored their performance in vitro, using 3D skin models. One of the studied patterns (pattern B) was shown to aid in the development of an in vitro rite-ridgelike skin model that resulted in the expression of relevant epithelial markers such as collagen IV and integrin β1. In summary, we have developed a new skin model including synthetic rete-ridgelike structures that replicate both morphology and function of the native dermal-epidermal junction and that offer new insights for the development of smart skin tissue engineering constructs.
David H. Ramos-Rodriguez, Sheila MacNeil, Frederik Claeyssens, and Ilida Ortega Asencio
MDPI AG
The recapitulation of the stem cell microenvironment is an emerging area of research that has grown significantly in the last 10 to 15 years. Being able to understand the underlying mechanisms that relate stem cell behavior to the physical environment in which stem cells reside is currently a challenge that many groups are trying to unravel. Several approaches have attempted to mimic the biological components that constitute the native stem cell niche, however, this is a very intricate environment and, although promising advances have been made recently, it becomes clear that new strategies need to be explored to ensure a better understanding of the stem cell niche behavior. The second strand in stem cell niche research focuses on the use of manufacturing techniques to build simple but functional models; these models aim to mimic the physical features of the niche environment which have also been demonstrated to play a big role in directing cell responses. This second strand has involved a more engineering approach in which a wide set of microfabrication techniques have been explored in detail. This review aims to summarize the use of these microfabrication techniques and how they have approached the challenge of mimicking the native stem cell niche.
Dina Abdelmoneim, Ghsaq M. Alhamdani, Thomas E. Paterson, Martin E. Santocildes Romero, Beatriz J. C. Monteiro, Paul V. Hatton, and Ilida Ortega Asencio
MDPI AG
Bone injuries that arise from trauma, cancer treatment, or infection are a major and growing global challenge. An increasingly ageing population plays a key role in this, since a growing number of fractures are due to diseases such as osteoporosis, which place a burden on healthcare systems. Current reparative strategies do not sufficiently consider cell-substrate interactions that are found in healthy tissues; therefore, the need for more complex models is clear. The creation of in vitro defined 3D microenvironments is an emerging topographically-orientated approach that provides opportunities to apply knowledge of cell migration and differentiation mechanisms to the creation of new cell substrates. Moreover, introducing biofunctional agents within in vitro models for bone regeneration has allowed, to a certain degree, the control of cell fate towards osteogenic pathways. In this research, we applied three methods for functionalizing spatially-confined electrospun artificial microenvironments that presented relevant components of the native bone stem cell niche. The biological and osteogenic behaviors of mesenchymal stromal cells (MSCs) were investigated on electrospun micro-fabricated scaffolds functionalized with extracellular matrix (ECM) proteins (collagen I), glycosaminoglycans (heparin), and ceramic-based materials (bioglass). Collagen, heparin, and bioglass (BG) were successfully included in the models without modifying the fibrous structures offered by the polycaprolactone (PCL) scaffolds. Mesenchymal stromal cells (MSCs) were successfully seeded in all the biofunctional scaffolds and they showed an increase in alkaline phosphatase production when exposed to PCL/BG composites. This research demonstrates the feasibility of manufacturing smart and hierarchical artificial microenvironments for studying stem cell behavior and ultimately the potential of incorporating these artificial microenvironments into multifunctional membranes for bone tissue regeneration
Thomas E. Paterson, Rui Shi, Jingjing Tian, Caroline J. Harrison, Mailys De Sousa Mendes, Paul V. Hatton, Zhou Li, and Ilida Ortega
MDPI AG
Preventing the development of osteomyelitis while enhancing bone regeneration is challenging, with relatively little progress to date in translating promising technologies to the clinic. Nanoscale hydroxyapatite (nHA) has been employed as a bone graft substitute, and recent work has shown that it may be modified with silver to introduce antimicrobial activity against known pathogens. The aim of this study was to incorporate silver-doped nHA into electrospun scaffolds for applications in bone repair. Silver-doped nHA was produced using a modified, rapid mixing, wet precipitation method at 2, 5, 10 mol.% silver. The silver-doped nHA was added at 20 wt.% to a polycaprolactone solution for electrospinning. Bacteria studies demonstrated reduced bacterial presence, with Escherichia coli and Staphylococcus aureus undetectable after 96 h of exposure. Mesenchymal stem cells (MSCs) were used to study both toxicity and osteogenicity of the scaffolds using PrestoBlue® and alkaline phosphatase (ALP) assays. Innovative silver nHA scaffolds significantly reduced E. coli and S. aureus bacterial populations while maintaining cytocompatibility with mammalian cells and enhancing the differentiation of MSCs into osteoblasts. It was concluded that silver-doped nHA containing scaffolds have the potential to act as an antimicrobial device while supporting bone tissue healing for applications in orthopedic and dental bone surgery.
Charanya Ramachandran, Virender S Sangwan, Ilida Ortega, Upendra Bhatnagar, Sadik Mohmad Abdulhamid Mulla, Rob McKean, and Sheila MacNeil
BMJ
AimThe aim of this study was to assess the local and systemic response to poly-lactic co-glycolic acid (PLGA) 50:50 membranes, developed as synthetic biodegradable alternatives to the use of human donor amniotic membrane in the treatment of limbal stem cell deficiency.MethodsPLGA membranes of 2 cm diameter and 50 µm thickness were placed on one eye of rabbits and secured in place using fibrin glue and a bandage contact lens, suturing the eye close with a single stitch. Control animals were treated identically, with the absence of the membranes. Plain and microfabricated electrospun membranes (containing micropockets which roughly emulate the native limbal niche) were examined over 29 days. All animals were subjected to a detailed gross and histopathological observation as well as a detailed examination of the eye.ResultsApplication of the membranes both with and without microfabricated pockets did not adversely affect animal welfare. There was complete degradation of the membranes by day 29. The membranes did not induce any significant local or systemic toxicity. Conjunctival congestion and corneal vascularisation were noted in a few control and PLGA-treated animals. Intraocular pressure was normal and the retinal status was unaltered. The ocular surface was clear and intact in all animals by the end of 29 days.ConclusionMembranes of 50:50 PLGA can be safely applied to rabbit corneas without inducing any local or systemic toxicity and these break down completely within 29 days.
Safiyya Yousaf, Saeed Heidari Keshel, Gholam Ali Farzi, Majid Momeni-Moghadam, Ehsaneh Daghigh Ahmadi, Ilida Ortega Asencio, Masoud Mozafari, and Farshid Sefat
Elsevier
Ilida Ortega Asencio, Shweta Mittar, Colin Sherborne, Ahtasham Raza, Frederik Claeyssens, and Sheila MacNeil
SAGE Publications
The continual renewal of the epidermis is thought to be related to the presence of populations of epidermal stem cells residing in physically protected microenvironments (rete ridges) directly influenced by the presence of mesenchymal fibroblasts. Current skin in vitro models do acknowledge the influence of stromal fibroblasts in skin reorganisation but the study of the effect of the rete ridge-microenvironment on epidermal renewal still remains a rich topic for exploration. We suggest there is a need for the development of new in vitro models in which to study epithelial stem cell behaviour prior to translating these models into the design of new cell-free biomaterial devices for skin reconstruction. In this study, we aimed to develop new prototype epidermal-like layers containing pseudo-rete ridge structures for studying the effect of topographical cues on epithelial cell behaviour. The models were designed using a range of three-dimensional electrospun microfabricated scaffolds. This was achieved via the utilisation of polyethylene glycol diacrylate to produce a reusable template over which poly(3-hydrroxybutyrate- co-3-hydroxyvalerate) was electrospun. Initial investigations studied the behaviour of keratinocytes cultured on models using plain scaffolds (without the presence of intricate topography) versus keratinocytes cultured on scaffolds containing microfeatures.
Thomas E Paterson, Selina N Beal, Martin E Santocildes-Romero, Alfred T Sidambe, Paul V Hatton, and Ilida Ortega Asencio
SAGE Publications
Additive manufacturing technologies enable the creation of very precise and well-defined structures that can mimic hierarchical features of natural tissues. In this article, we describe the development of a manufacturing technology platform to produce innovative biodegradable membranes that are enhanced with controlled microenvironments produced via a combination of selective laser melting techniques and conventional electrospinning. This work underpins the manufacture of a new generation of biomaterial devices that have significant potential for use as both basic research tools and components of therapeutic implants. The membranes were successfully manufactured and a total of three microenvironment designs (niches) were chosen for thorough characterisation. Scanning electron microscopy analysis demonstrated differences in fibre diameters within different areas of the niche structures as well as differences in fibre density. We also showed the potential of using the microfabricated membranes for supporting mesenchymal stromal cell culture and proliferation. We demonstrated that mesenchymal stromal cells grow and populate the membranes penetrating within the niche-like structures. These findings demonstrate the creation of a very versatile tool that can be used in a variety of tissue regeneration applications including bone healing.
Lindsey Dew, William R. English, Ilida Ortega, Frederik Claeyssens, and Sheila MacNeil
S. Karger AG
One of the greatest challenges currently faced in tissue engineering is the incorporation of vascular networks within tissue-engineered constructs. The aim of this study was to develop a technique for producing a perfusable, 3-dimensional, cell-friendly model of vascular structures that could be used to study the factors affecting angiogenesis and vascular biology in engineered systems in more detail. Initially, biodegradable synthetic pseudovascular networks were produced via the combination of robocasting and electrospinning techniques. The internal surfaces of the vascular channels were then recellularized with human dermal microvascular endothelial cells (HDMECs) with and without the presence of human dermal fibroblasts (HDFs) on the outer surface of the scaffold. After 7 days in culture, channels that had been reseeded with HDMECs alone demonstrated irregular cell coverage. However, when using a co-culture of HDMECs inside and HDFs outside the vascular channels, coverage was found to be continuous throughout the internal channel. Using this cell combination, collagen gels loaded with vascular endothelial growth factor were deposited onto the outer surface of the scaffold and cultured for a further 7 days. After this, endothelial cell outgrowth from within the channels into the collagen gel was observed, showing that the engineered vasculature maintains its capacity for angiogenesis. Furthermore, the HDMECs appeared to have formed perfusable tubules within the gel. These results show promising steps towards the development of an in vitro platform for studying angiogenesis and vascular biology in a tissue engineering context.
Atra Malayeri, Colin Sherborne, Thomas Paterson, Shweta Mittar, Ilida Ortega Asencio, Paul V. Hatton, and Frederik Claeyssens
AccScience Publishing
This paper describes the direct laser write of a photocurable acrylate-based PolyHIPE (High Internal Phase Emulsion) to produce scaffolds with both macro- and microporosity, and the use of these scaffolds in osteosarco-ma-based 3D cell culture. The macroporosity was introduced via the application of stereolithography to produce a clas-sical woodpile structure with struts having an approximate diameter of 200 ?m and pores were typically around 500 ?m in diameter. The PolyHIPE retained its microporosity after stereolithographic manufacture, with a range of pore sizes typically between 10 and 60 ?m (with most pores between 20 and 30 ?m). The resulting scaffolds were suitable substrates for further modification using acrylic acid plasma polymerisation. This scaffold was used as a structural mimic of the trabecular bone and in vitro determination of biocompatibility using cultured bone cells (MG63) demon-strated that cells were able to colonise all materials tested, with evidence that acrylic acid plasma polymerisation im-proved biocompatibility in the long term. The osteosarcoma cell culture on the 3D printed scaffold exhibits different growth behaviour than observed on tissue culture plastic or a flat disk of the porous material; tumour spheroids are ob-served on parts of the scaffolds. The growth of these spheroids indicates that the osteosarcoma behave more akin to in vivo in this 3D mimic of trabecular bone. It was concluded that PolyHIPEs represent versatile biomaterial systems with considerable potential for the manufacture of complex devices or scaffolds for regenerative medicine. In particular, the possibility to readily mimic the hierarchical structure of native tissue enables opportunities to build in vitro models closely resembling tumour tissue.
Qasim A Rafiq, Ilida Ortega, Stuart I Jenkins, Samantha L Wilson, Asha K Patel, Amanda L Barnes, Christopher F Adams, Derfogail Delcassian, and David Smith
Future Medicine Ltd
Although the importance of translation for the development of tissue engineering, regenerative medicine and cell-based therapies is widely recognized, the process of translation is less well understood. This is particularly the case among some early career researchers who may not appreciate the intricacies of translational research or make decisions early in development which later hinders effective translation. Based on our own research and experiences as early career researchers involved in tissue engineering and regenerative medicine translation, we discuss common pitfalls associated with translational research, providing practical solutions and important considerations which will aid process and product development. Suggestions range from effective project management, consideration of key manufacturing, clinical and regulatory matters and means of exploiting research for successful commercialization.
Ilida Ortega, Lindsey Dew, Adam G. Kelly, Chuh K. Chong, Sheila MacNeil, and Frederik Claeyssens
Royal Society of Chemistry (RSC)
Electrospinning has been combined with robocasting using alginate as a sacrificial template for the creation of bespoke and perfusable artificial vascular networks.
Andrew A. Gill, Ílida Ortega, Stephen Kelly, and Frederik Claeyssens
Springer Science and Business Media LLC
P. Deshpande, I. Ortega, F. Sefat, V. S. Sangwan, N. Green, F. Claeyssens, and S. MacNeil
Association for Research in Vision and Ophthalmology (ARVO)
Ílida Ortega, Farshid Sefat, Pallavi Deshpande, Thomas Paterson, Charanya Ramachandran, Anthony J. Ryan, Sheila MacNeil, and Frederik Claeyssens
MyJove Corporation
Corneal problems affect millions of people worldwide reducing their quality of life significantly. Corneal disease can be caused by illnesses such as Aniridia or Steven Johnson Syndrome as well as by external factors such as chemical burns or radiation. Current treatments are (i) the use of corneal grafts and (ii) the use of stem cell expanded in the laboratory and delivered on carriers (e.g., amniotic membrane); these treatments are relatively successful but unfortunately they can fail after 3-5 years. There is a need to design and manufacture new corneal biomaterial devices able to mimic in detail the physiological environment where stem cells reside in the cornea. Limbal stem cells are located in the limbus (circular area between cornea and sclera) in specific niches known as the Palisades of Vogt. In this work we have developed a new platform technology which combines two cutting-edge manufacturing techniques (microstereolithography and electrospinning) for the fabrication of corneal membranes that mimic to a certain extent the limbus. Our membranes contain artificial micropockets which aim to provide cells with protection as the Palisades of Vogt do in the eye.
Farshid Sefat, Ilida Ortega, Robert McKean, Pallavi Deshpande, Charanya Ramachandran, Christopher J Hill, Svetomir B Tzokov, Frederik Claeyssens, Virender S Sangwan, Anthony J Ryan,et al.
IEEE
Our overall aim is to develop a synthetic off-the-shelf alternative to human amniotic membrane which is currently used for delivering cultured limbal stem cells to the cornea in patients who suffer scarring of the cornea because of the loss of limbal stem cells. We have recently reported that both cultured cells and limbal explants grow well on electrospun Poly(D, L-lactide-co-glycolide) (PLGA) (44 kg/mol) with a 50:50 ratio of lactide and glycolide and sterilized with γ-irradiation. Prior to undertaking a clinical study our immediate aim now is to achieve long term storage of the membranes in convenient to use packaging. Membranes were electrospun from Poly(D, L-lactide-co-glycolide) (44 kg/mol) with a 50:50 ratio of lactide and glycolide and sterilized with γ-irradiation and then stored dry (with desiccant) for several months at -80°C and -20°C, Room temperature (UK and India), 37°C and 50°C. We explored the contribution of vacuum sealing and the use of a medical grade bag (PET/Foil/LDPE) to achieve a longer shelf life. Confirmation of membranes being suitable for clinical use was obtained by culturing tissue explants on membranes post storage. When scaffolds were stored dry the rate of breakdown was both temperature and time dependent. At -20°C and -80°C there was no change in fiber diameter over 18 months of storage, and membranes were stable for 12 months at 4°C while at 50°C (above the transition temperature for PLGA) scaffolds lost integrity after several weeks. The use of vacuum packaging and a medical grade bag both improved the storage shelf-life of the scaffolds. The impact of temperature on storage is summarized beneath. We report that this synthetic membrane can be used as an off-the-shelf or-out-of-the freezer alternative to the amniotic membrane for corneal regeneration.
Ilida Ortega, Robert McKean, Anthony J. Ryan, Sheila MacNeil, and Frederik Claeyssens
Royal Society of Chemistry (RSC)
Scarring of the cornea affects thousands of people every year, significantly reducing the quality of life and potentially leading to corneal blindness. Although cultured limbal epithelial cells have been used to regenerate scarred corneas for more than 15 years, the culture strategies do not deliver cells under the physiological conditions they experience in vivo. One of the main characteristics of stem cells is their ability to self-renew to maintain a tissue for a lifetime. Stem cells' unique characteristics are thought to be at least partially due to their location within enclosed protective microenvironments or niches. For corneal stem cells these are located in intricate microenvironments or niches situated within areas of the limbal region known as the Palisades of Vogt. These are located in the limbus which is the area between the cornea and sclera. In this study we introduced micropockets into biodegradable microfabricated membranes and explored the potential contribution of these structures to limbal cell migration and their ability to deliver cells to a 3D cornea model. Membranes with micropockets were characterized using SEM, OCT, light microscopy and nanoindentation. Results indicate that the micropockets enhance the migration of cells from limbal explants and cells transfer readily from the membranes to the ex vivo cornea model.
Ílida Ortega, Pallavi Deshpande, Andrew A Gill, Sheila MacNeil, and Frederik Claeyssens
IOP Publishing
The aim of this study was to develop a synthetic alternative to the human corneal limbus for use initially as an ex vivo model in which to study corneal stem cell function within a niche environment and ultimately to develop an implantable limbus for future clinical use. Microstereolithography was used for the fabrication of polyethylene glycol diacrylate (PEGDA) based rings on a macroscopic (1.2 cm) scale containing unique microfeatures (pockets) which were then modified with fibronectin to promote cell adhesion. These rings were designed to mimic the limbal area of the eye containing structures of the approximate size and shape of the stem cell microenvironments found in the palisades of Vogt. The attachment of rabbit limbal fibroblasts and rabbit limbal epithelial cells to the PEGDA rings was increased by pretreating the microfabricated structures with biotinylated fibronectin. Cell outgrowth from fibronectin coated microfabricated structures was 50% greater than from rings without structures or fibronectin coating. The cell loaded rings were then placed on an ex vivo wounded cornea model and the outgrowth of cells to form a multilayered epithelium was observed. We suggest this is a new approach to investigating limbal stem cells niches and the first steps towards a new approach for corneal regeneration.
Ílida Ortega, Anthony J. Ryan, Pallavi Deshpande, Sheila MacNeil, and Frederik Claeyssens
Elsevier BV
Pablo Botella, Ílida Ortega, Manuel Quesada, Roque F. Madrigal, Carlos Muniesa, Antonio Fimia, Eduardo Fernández, and Avelino Corma
Royal Society of Chemistry (RSC)
Combined chemo and photothermal therapy in in vitro testing has been achieved by means of multifunctional nanoparticles formed by plasmonic gold nanoclusters with a protecting shell of porous silica that contains an antitumor drug. We propose a therapeutic nanoplatform that associates the optical activity of small gold nanoparticles aggregates with the cytotoxic activity of 20(S)-camptothecin simultaneously released for the efficient destruction of cancer cells. For this purpose, a method was used for the controlled assembly of gold nanoparticles into stable clusters with a tailored absorption cross-section in the vis/NIR spectrum, which involves aggregation in alkaline medium of 15 nm diameter gold colloids protected with a thin silica layer. Clusters were further encapsulated in an ordered homogeneous mesoporous silica coating that provides biocompatibility and stability in physiological fluids. After internalization in 42-MG-BA human glioma cells, these protected gold nanoclusters were able to produce effective photothermolysis under femtosecond pulse laser irradiation of 790 nm. Cell death occurred by combination of a thermal mechanism and mechanical disruption of the membrane cell due to induced generation of micrometer-scale bubbles by vaporizing the water inside the channels of the mesoporous silica coating. Moreover, the incorporation of 20(S)-camptothecin within the pores of the external shell, which was released during the process, provoked significant cell death increase. This therapeutic model could be of interest for application in the treatment and suppression of non-solid tumors.