Master of Science, University Of Aston In Birmingham (2013)
Doctor of Philosophy, University Of Nottingham (2018)
Bachelor of Science, University Of Aston In Birmingham (2010)
Postdoctoral Researcher, Stanford University, Department of Ophthalmology, Stanford School of Medicine
Postdoctoral Research Associate, University of Liverpool, Department of Eye and Vision Science & Department of Musculoskeletal Ageing Science, Institute of Life Course and Medical Sciences
Postdoctoral Research Associate, University of Sheffield, Bioengineering & Health Technologies (BHT), School of Dentistry
PhD, University of Nottingham, Pharmacy (2018)
MSc, Aston University, Pharmacology (2013)
BSc, Aston University, Biological Chemistry (2010)
Albert Wu, Postdoctoral Faculty Sponsor
Corneal and Limbal Alkali Injury Induction Using a Punch-Trephine Technique in a Mouse Model.
Journal of visualized experiments : JoVE
The cornea is critical for vision, and corneal healing after trauma is fundamental in maintaining its transparency and function. Through the study of corneal injury models, researchers aim to enhance their understanding of how the cornea heals and develop strategies to prevent and manage corneal opacities. Chemical injury is one of the most popular injury models that has extensively been studied on mice. Most previous investigators have used a flat paper soaked in sodium hydroxide to induce corneal injury. However, inducing corneal and limbal injury using flat filter paper is unreliable, since the mouse cornea is highly curved. Here, we present a new instrument, a modified biopsy punch, that enables the researchers to create a well-circumscribed, localized, and evenly distributed alkali injury to the murine cornea and limbus. This punch-trephine method enables researchers to induce an accurate and reproducible chemical burn to the entire murine cornea and limbus while leaving other structures, such as the eyelids, unaffected by the chemical. Moreover, this study introduces an enucleation technique that preserves the medial caruncle as a landmark for identifying the nasal side of the globe. The bulbar and palpebral conjunctiva, and lacrimal gland are also kept intact using this technique. Ophthalmologic examinations were performed via slit lamp biomicroscope and fluorescein staining on days 0, 1, 2, 6, 8, and 14 post-injury. Clinical, histological, and immunohistochemical findings confirmed limbal stem cell deficiency and ocular surface regeneration failure in all experimental mice. The presented alkali corneal injury model is ideal for studying limbal stem cell deficiency, corneal inflammation, and fibrosis. This method is also suitable for investigating pre-clinical and clinical efficacies of topical ophthalmologic medications on the murine corneal surface.
View details for DOI 10.3791/65609
View details for PubMedID 37590514
Cell-controlled dynamic surfaces for skeletal stem cell growth and differentiation.
2022; 12 (1): 8165
Skeletal stem cells (SSCs, or mesenchymal stromal cells typically referred to as mesenchymal stem cells from the bone marrow) are a dynamic progenitor population that can enter quiescence, self-renew or differentiate depending on regenerative demand and cues from their niche environment. However, ex vivo, in culture, they are grown typically on hard polystyrene surfaces, and this leads to rapid loss of the SSC phenotype. While materials are being developed that can control SSC growth and differentiation, very few examples of dynamic interfaces that reflect the plastic nature of the stem cells have, to date, been developed. Achieving such interfaces is challenging because of competing needs: growing SSCs require lower cell adhesion and intracellular tension while differentiation to, for example, bone-forming osteoblasts requires increased adhesion and intracellular tension. We previously reported a dynamic interface where the cell adhesion tripeptide arginine-glycine-aspartic acid (RGD) was presented to the cells upon activation by user-added elastase that cleaved a bulky blocking group hiding RGD from the cells. This allowed for a growth phase while the blocking group was in place and the cells could only form smaller adhesions, followed by an osteoblast differentiation phase that was induced after elastase was added which triggered exposure of RGD and subsequent cell adhesion and contraction. Here, we aimed to develop an autonomous system where the surface is activated according to the need of the cell by using matrix metalloprotease (MMP) cleavable peptide sequences to remove the blocking group with the hypothesis that the SSCs would produce higher levels of MMP as the cells reached confluence. The current studies demonstrate that SSCs produce active MMP-2 that can cleave functional groups on a surface. We also demonstrate that SSCs can grow on the uncleaved surface and, with time, produce osteogenic marker proteins on the MMP-responsive surface. These studies demonstrate the concept for cell-controlled surfaces that can modulate adhesion and phenotype with significant implications for stem cell phenotype modulation.
View details for DOI 10.1038/s41598-022-12057-z
View details for PubMedID 35581256
Biofabrication of Artificial Stem Cell Niches in the Anterior Ocular Segment
2021; 8 (10)
The anterior segment of the eye is a complex set of structures that collectively act to maintain the integrity of the globe and direct light towards the posteriorly located retina. The eye is exposed to numerous physical and environmental insults such as infection, UV radiation, physical or chemical injuries. Loss of transparency to the cornea or lens (cataract) and dysfunctional regulation of intra ocular pressure (glaucoma) are leading causes of worldwide blindness. Whilst traditional therapeutic approaches can improve vision, their effect often fails to control the multiple pathological events that lead to long-term vision loss. Regenerative medicine approaches in the eye have already had success with ocular stem cell therapy and ex vivo production of cornea and conjunctival tissue for transplant recovering patients' vision. However, advancements are required to increase the efficacy of these as well as develop other ocular cell therapies. One of the most important challenges that determines the success of regenerative approaches is the preservation of the stem cell properties during expansion culture in vitro. To achieve this, the environment must provide the physical, chemical and biological factors that ensure the maintenance of their undifferentiated state, as well as their proliferative capacity. This is likely to be accomplished by replicating the natural stem cell niche in vitro. Due to the complex nature of the cell microenvironment, the creation of such artificial niches requires the use of bioengineering techniques which can replicate the physico-chemical properties and the dynamic cell-extracellular matrix interactions that maintain the stem cell phenotype. This review discusses the progress made in the replication of stem cell niches from the anterior ocular segment by using bioengineering approaches and their therapeutic implications.
View details for DOI 10.3390/bioengineering8100135
View details for Web of Science ID 000716981500001
View details for PubMedID 34677208
View details for PubMedCentralID PMC8533470
Tuning Electrospun Substrate Stiffness for the Fabrication of a Biomimetic Amniotic Membrane Substitute for Corneal Healing
ACS APPLIED BIO MATERIALS
2021; 4 (7): 5638-5649
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.
View details for DOI 10.1021/acsabm.1c00436
View details for Web of Science ID 000675478800023
View details for PubMedID 35006734
Responsive cell-material interfaces
2015; 10 (5): 849-871
Major design aspects for novel biomaterials are driven by the desire to mimic more varied and complex properties of a natural cellular environment with man-made materials. The development of stimulus responsive materials makes considerable contributions to the effort to incorporate dynamic and reversible elements into a biomaterial. This is particularly challenging for cell-material interactions that occur at an interface (biointerfaces); however, the design of responsive biointerfaces also presents opportunities in a variety of applications in biomedical research and regenerative medicine. This review will identify the requirements imposed on a responsive biointerface and use recent examples to demonstrate how some of these requirements have been met. Finally, the next steps in the development of more complex biomaterial interfaces, including multiple stimuli-responsive surfaces, surfaces of 3D objects and interactive biointerfaces will be discussed.
View details for DOI 10.2217/NNM.14.222
View details for Web of Science ID 000351930700015
View details for PubMedID 25816884