Imperial College London

ProfessorRylieGreen

Faculty of EngineeringDepartment of Bioengineering

Head of the Department of Bioengineering
 
 
 
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Contact

 

+44 (0)20 7594 0943rylie.green

 
 
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Location

 

3.05Bessemer BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

113 results found

Boulingre M, Portillo-Lara R, Green RA, 2023, Biohybrid neural interfaces: improving the biological integration of neural implants., Chem Commun (Camb), Vol: 59, Pages: 14745-14758

Implantable neural interfaces (NIs) have emerged in the clinic as outstanding tools for the management of a variety of neurological conditions caused by trauma or disease. However, the foreign body reaction triggered upon implantation remains one of the major challenges hindering the safety and longevity of NIs. The integration of tools and principles from biomaterial design and tissue engineering has been investigated as a promising strategy to develop NIs with enhanced functionality and performance. In this Feature Article, we highlight the main bioengineering approaches for the development of biohybrid NIs with an emphasis on relevant device design criteria. Technical and scientific challenges associated with the fabrication and functional assessment of technologies composed of both artificial and biological components are discussed. Lastly, we provide future perspectives related to engineering, regulatory, and neuroethical challenges to be addressed towards the realisation of the promise of biohybrid neurotechnology.

Journal article

Chapman CAR, Fernandez-Patel S, Jahan N, Cuttaz EA, Novikov A, Goding JA, Green RAet al., 2023, Controlled electroactive release from solid-state conductive elastomer electrodes, Materials Today Bio, Vol: 23, ISSN: 2590-0064

This work highlights the development of a conductive elastomer (CE) based electrophoretic platform that enables the transfer of charged molecules from a solid-state CE electrode directly to targeted tissues. Using an elastomer-based electrode containing poly (3,4-ethylenedioxythiophene) nanowires, controlled electrophoretic delivery of methylene blue (MB) and fluorescein (FLSC) was achieved with applied voltage. Electroactive release of positively charged MB and negatively charged FLSC achieved 33.19 ± 6.47 μg release of MB and 22.36 ± 3.05 μg release of FLSC, a 24 and 20-fold increase in comparison to inhibitory voltages over 1 h. Additionally, selective, and sequential release of the two oppositely charged molecules from a single CE device was demonstrated, showing the potential of this device to be used in multi-drug treatments.

Journal article

Steenbergen N, Busha I, Morgan A, Mattathil C, Levy Pinto A, Spyridakos F, Sokolovskiy I, Tahirbegi B, Chapman C, Cuttaz E, Litvinova K, Goding J, Green Ret al., 2023, Surface electromyography using dry polymeric electrodes, APL Bioengineering, Vol: 7, ISSN: 2473-2877

Conventional wet Ag/AgCl electrodes are widely used in electrocardiography, electromyography (EMG), and electroencephalography (EEG) and are considered the gold standard for biopotential measurements. However, these electrodes require substantial skin preparation, are single use, and cannot be used for continuous monitoring (>24 h). For these reasons, dry electrodes are preferable during surface electromyography (sEMG) due to their convenience, durability, and longevity. Dry conductive elastomers (CEs) combine conductivity, flexibility, and stretchability. In this study, CEs combining poly(3,4-ehtylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) in polyurethane are explored as dry, skin contacting EMG electrodes. This study compares these CE electrodes to commercial wet Ag/AgCl electrodes in five subjects, classifying four movements: open hand, fist, wrist extension, and wrist flexion. Classification accuracy is tested using a backpropagation artificial neural network. The control Ag/AgCl electrodes have a 98.7% classification accuracy, while the dry conductive elastomer electrodes have a classification accuracy of 99.5%. As a conclusion, PEDOT based dry CEs were shown to successfully function as on-skin electrodes for EMG recording, matching the performance of Ag/AgCl electrodes, while addressing the need for minimal skin prep, no gel, and wearable technology.

Journal article

Cuttaz EA, Syed O, Chapman CAR, Goding JA, Bailey ZK, Portillo-Lara R, Green RAet al., 2023, A Pilot In Vivo Study of Flexible Fully Polymeric Nerve Cuff Electrodes., Annu Int Conf IEEE Eng Med Biol Soc, Vol: 2023, Pages: 1-4

Recent trends in the field of bioelectronics have been focused on the development of electrodes that facilitate safe and efficient stimulation of nervous tissues. Novel conducting polymer (CP) based materials, such as flexible and fully polymeric conductive elastomers (CEs), constitute a promising alternative to improve on the limitations of current metallic devices. This pilot study demonstrates the performance of tripolar CE-based peripheral nerve cuffs compared to current commercial tripolar platinum-iridium (PtIr) nerve cuffs in vivo. CE and metallic cuff devices were implanted onto rodent sciatic nerves for a period of 8 weeks. Throughout the entire study, the CE device demonstrated improved charge transfer and electrochemical safety compared to the PtIr cuff, able to safely inject 2 to 3 times more charge. In comparison to the commercial control, the CE cuff was able to record in the in vivo setting with reduced noise and produced smaller voltages at all simulation levels. CE technologies provide a promising alternative to metallic devices for the development of bioelectronics with enhanced chronic device functionality.

Journal article

Peressotti S, Lara RP, Goding J, Green Ret al., 2023, An Electrical Stimulation Device For In Vitro Neural Engineering., Annu Int Conf IEEE Eng Med Biol Soc, Vol: 2023, Pages: 1-4

Due to the intrinsically low turnover of neural tissues, regenerative therapies have gained significant interest in the context of degenerative diseases and injury to the central and peripheral nervous systems. Although a range of neuroregenerative strategies involving cell transplants and drugs have been explored, these are often limited by low efficacy and unwanted side effects. Electrical stimulation (ES) is thought to modulate the proliferation and differentiation of neural stem cells (NSCs), and thus it represents a promising strategy for neuroregenerative therapies. However, its influence on the biology of endogenous and exogenous NSCs, and the effect of different stimulation paradigms remains unexplored. Additionally, the variability of stimulation platforms and parameters employed in previous studies prevents reliable and reproducible discoveries. Therefore, there is a need to develop versatile and robust tools to study the effect of electrical stimulation on NSC fate in vitro. This paper outlines the development and functional application of a standardised, electrically stable, and easily reproducible ES platform for in vitro neuroregeneration applications.Clinical Relevance- The elucidation of the cellular and molecular mechanisms underlying the effect of ES paradigms on NSCs proliferation and differentiation holds great potential for the development of neuroregenerative therapies.

Journal article

Boulingre M, Genta M, Goding J, Lara RP, Green Ret al., 2023, Tissue-Engineered Interfaces to Enhance the Biointegration of Neural Implants, European Chapter of the Tissue-Engineering-and-Regenerative-Medicine-International-Society (TERMIS), Publisher: MARY ANN LIEBERT, INC, ISSN: 1937-3341

Conference paper

Peressotti S, Lara RP, Goding J, Green Ret al., 2023, TOWARDS NON-INVASIVE DEEP BRAIN STIMULATION THERAPIES FOR NEURODEGENERATIVE DISORDERS, Tissue Engineering and Regenerative Medicine International Society (TERMIS), Publisher: MARY ANN LIEBERT, INC, Pages: 1204-1205, ISSN: 1937-3341

Conference paper

Genta M, Lara RP, Goding J, Green Ret al., 2023, TISSUE-ENGINEERED NEURAL TISSUE INTERFACES FOR NEXT GENERATION BIONIC DEVICES, Tissue Engineering and Regenerative Medicine International Society (TERMIS), Publisher: MARY ANN LIEBERT, INC, Pages: 1233-1234, ISSN: 1937-3341

Conference paper

Xiong Z, Huang W, Liang Q, Cao Y, Liu S, He Z, Zhang R, Zhang B, Green R, Zhang S, Li Det al., 2022, Harnessing the 2D Structure-Enabled Viscoelasticity of Graphene-Based Hydrogel Membranes for Chronic Neural Interfacing (vol 6, 2200022, 2022), SMALL METHODS, Vol: 6, ISSN: 2366-9608

Journal article

Rapeaux A, Syed O, Cuttaz E, Chapman C, Green R, Constandinou Tet al., 2022, Preparation of rat sciatic nerve for ex vivo neurophysiology, Jove-Journal of Visualized Experiments, Vol: 185, Pages: 1-14, ISSN: 1940-087X

Ex vivo preparations enable the study of many neurophysiological processes in isolation from the rest of the body while preserving local tissue structure. This work describes the preparation of rat sciatic nerves for ex vivo neurophysiology, including buffer preparation, animal procedures, equipment setup and neurophysiological recording. This work provides an overview of the different types of experiments possible with this method. The outlined method aims to provide 6 h of stimulation and recording on extracted peripheral nerve tissue in tightly controlled conditions for optimal consistency in results. Results obtained using this method are A-fibre compound action potentials (CAP) with peak-to-peak amplitudes in the millivolt range over the entire duration of the experiment. CAP amplitudes and shapes are consistent and reliable, making them useful to test and compare new electrodes to existing models, or the effects of interventions on the tissue, such as the use of chemicals, surgical alterations, or neuromodulatory stimulation techniques. Both conventional commercially available cuff electrodes with platinum-iridium contacts and custom-made conductive elastomer electrodes were tested and gave similar results in terms of nerve stimulus strength-duration response.

Journal article

Xiong Z, Huang W, Liang Q, Cao Y, Liu S, He Z, Zhang R, Zhang B, Green R, Zhang S, Li Det al., 2022, Harnessing the 2D structure-enabled viscoelasticity of graphene-based hydrogel membranes for chronic neural interfacing, small methods, Vol: 6, ISSN: 2366-9608

Stiffness and viscoelasticity of neural implants regulate the foreign body response. Recent studies have suggested the use of elastic or viscoelastic materials with tissue-like stiffness for long-term neural electrical interfacing. Herein, the authors find that a viscoelastic multilayered graphene hydrogel (MGH) membrane, despite exhibiting a much higher Young's modulus than nerve tissues, shows little inflammatory response after 8-week implantation in rat sciatic nerves. The MGH membrane shows significant viscoelasticity due to the slippage between graphene nanosheets, facilitating its seamless yet minimally compressive interfacing with nerves to reduce the inflammation caused by the stiffness mismatch. When used as neural stimulation electrodes, the MGH membrane can offer abundant ion-accessible surfaces to bring a charge injection capacity 1–2 orders of magnitude higher than its traditional Pt counterpart, and further demonstrates chronic neural therapy potential in low-voltage modulation of rat blood pressure. This work suggests that the emergence of 2D nanomaterials and particularly their unique structural attributes can be harnessed to enable new bio-interfacing design strategies.

Journal article

Vallejo-Giraldo C, Genta M, Portillo-Lara R, Goding J, Green Ret al., 2022, FIBRILLAR MESH HYDROGELS FOR LIVING BIONIC DEVICES, 6th World Congress of the Tissue-Engineering-and-Regenerative-Medicine-International-Society (TERMIS), Publisher: MARY ANN LIEBERT, INC, Pages: S264-S265, ISSN: 1937-3341

Conference paper

Genta M, Vallejo-Giraldo C, Goding J, Green Ret al., 2022, CELL-MATERIAL INTERACTION IN BIOSYNTHETIC HYDROGELS FOR BIOMIMETIC NEURAL INTERFACES, Publisher: MARY ANN LIEBERT, INC, Pages: S244-S244, ISSN: 1937-3341

Conference paper

Peressotti S, Goding J, Green R, 2022, BOOSTING NEUROGENESIS: A NON-INVASIVE DEEP BRAIN STIMULATION PLATFORM FOR NEUROREGENERATION THERAPIES, Publisher: MARY ANN LIEBERT, INC, Pages: S190-S190, ISSN: 1937-3341

Conference paper

Koehl G, Goding J, Di Giovanni S, Green Ret al., 2022, SELF-ASSEMBLED CONDUCTIVE NANOFIBERS FOR SPINAL CORD REGENERATION, Publisher: MARY ANN LIEBERT, INC, Pages: S188-S188, ISSN: 1937-3341

Conference paper

Kanelos E, Green R, Goding J, 2022, PSEUDOPOLYROTAXANE HYDROGELS FOR NEURAL TISSUE ENGINEERING APPLICATIONS, Publisher: MARY ANN LIEBERT, INC, Pages: S176-S176, ISSN: 1937-3341

Conference paper

Cuttaz EA, Chapman CAR, Goding JA, Green RAet al., 2022, CONDUCTIVE ELASTOMERS FOR APPLICATIONS IN FLEXIBLE BIOELECTRONIC DEVICES, Publisher: MARY ANN LIEBERT, INC, Pages: S251-S251, ISSN: 1937-3341

Conference paper

Chapman CAR, Patel SF, Cuttaz EA, Giraldo CV, Goding JA, Green RAet al., 2022, CONDUCTIVE ELASTOMER-BASED BIOELECTRONIC DEVICE FOR THE TARGETED DELIVERY OF CHEMOTHERAPY, Publisher: MARY ANN LIEBERT, INC, Pages: S259-S259, ISSN: 1937-3341

Conference paper

Novikov A, Goding J, Green RA, 2022, DEVELOPMENT OF FULLY-POLYMERIC ELECTRIC LEADS FOR BIOELECTRONICS, Publisher: MARY ANN LIEBERT, INC, Pages: S136-S137, ISSN: 1937-3341

Conference paper

Chapman CAR, Cuttaz EA, Tahirbegi B, Novikov A, Petkos K, Koutsoftidis S, Drakakis EM, Goding JA, Green RAet al., 2022, Flexible Networks of Patterned Conducting Polymer Nanowires for Fully Polymeric Bioelectronics, ADVANCED NANOBIOMED RESEARCH, Vol: 2, ISSN: 2699-9307

Journal article

Heck J, Goding J, Lara RP, Green Ret al., 2022, The influence of physicochemical properties on the processibility of conducting polymers: A bioelectronics perspective, ACTA BIOMATERIALIA, Vol: 139, Pages: 259-279, ISSN: 1742-7061

Journal article

Cuttaz EA, Chapman CAR, Goding JA, Vallejo-Giraldo C, Syed O, Green RAet al., 2021, Flexible nanowire conductive elastomers for applications in fully polymeric bioelectronic devices., 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), Publisher: IEEE, Pages: 5872-5875

Soft, flexible polymer-based bioelectronics are a promising approach to minimize the chronic inflammatory reactions associated with metallic devices, impairing long-term device reliability and functionality. This work demonstrates the fabrication of conductive elastomers (CEs) consisting of chemically synthesized poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires embedded within a polyurethane (PU) elastomeric matrix, resulting in soft and flexible, fully polymeric electrode materials. Increasing PEDOT nanowire loadings resulted in an improvement in electrochemical properties and conductivity, an increased Young's modulus and reduced strain at failure. Nanowire CEs were also found to have significantly improved electrochemical performance compared to one of the standard electrode materials, platinum (Pt). Indirect in vitro cytocompatibility test was carried out to investigate the effect of leachable substances from the CE on primary rodent cells. Nanowire CEs provide a promising alternative to metals for the fabrication of soft bioelectronics.

Conference paper

Green RA, 2021, Possibilities in bioelectronics: Super humans or science fiction?, APL BIOENGINEERING, Vol: 5, ISSN: 2473-2877

Journal article

Portillo-Lara R, Goding JA, Green RA, 2021, Adaptive biomimicry: design of neural interfaces with enhanced biointegration, CURRENT OPINION IN BIOTECHNOLOGY, Vol: 72, Pages: 62-68, ISSN: 0958-1669

Journal article

Portillo-Lara R, Tahirbegi B, Chapman CAR, Goding JA, Green RAet al., 2021, Mind the gap: State-of-the-art technologies and applications for EEG-based brain-computer interfaces, APL Bioengineering, Vol: 5, Pages: 1-16, ISSN: 2473-2877

Brain–computer interfaces (BCIs) provide bidirectional communication between the brain and output devices that translate user intent into function. Among the different brain imaging techniques used to operate BCIs, electroencephalography (EEG) constitutes the preferred method of choice, owing to its relative low cost, ease of use, high temporal resolution, and noninvasiveness. In recent years, significant progress in wearable technologies and computational intelligence has greatly enhanced the performance and capabilities of EEG-based BCIs (eBCIs) and propelled their migration out of the laboratory and into real-world environments. This rapid translation constitutes a paradigm shift in human–machine interaction that will deeply transform different industries in the near future, including healthcare and wellbeing, entertainment, security, education, and marketing. In this contribution, the state-of-the-art in wearable biosensing is reviewed, focusing on the development of novel electrode interfaces for long term and noninvasive EEG monitoring. Commercially available EEG platforms are surveyed, and a comparative analysis is presented based on the benefits and limitations they provide for eBCI development. Emerging applications in neuroscientific research and future trends related to the widespread implementation of eBCIs for medical and nonmedical uses are discussed. Finally, a commentary on the ethical, social, and legal concerns associated with this increasingly ubiquitous technology is provided, as well as general recommendations to address key issues related to mainstream consumer adoption.

Journal article

Peressotti S, Koehl GE, Goding JA, Green RAet al., 2021, Self-assembling hydrogel structures for neural tissue repair, ACS Biomaterials Science and Engineering, Vol: 7, Pages: 4136-4163, ISSN: 2373-9878

Hydrogel materials have been employed as biological scaffolds for tissue regeneration across a wide range of applications. Their versatility and biomimetic properties make them an optimal choice for treating the complex and delicate milieu of neural tissue damage. Aside from finely tailored hydrogel properties, which aim to mimic healthy physiological tissue, a minimally invasive delivery method is essential to prevent off-target and surgery-related complications. The specific class of injectable hydrogels termed self-assembling peptides (SAPs), provide an ideal combination of in situ polymerization combined with versatility for biofunctionlization, tunable physicochemical properties, and high cytocompatibility. This review identifies design criteria for neural scaffolds based upon key cellular interactions with the neural extracellular matrix (ECM), with emphasis on aspects that are reproducible in a biomaterial environment. Examples of the most recent SAPs and modification methods are presented, with a focus on biological, mechanical, and topographical cues. Furthermore, SAP electrical properties and methods to provide appropriate electrical and electrochemical cues are widely discussed, in light of the endogenous electrical activity of neural tissue as well as the clinical effectiveness of stimulation treatments. Recent applications of SAP materials in neural repair and electrical stimulation therapies are highlighted, identifying research gaps in the field of hydrogels for neural regeneration.

Journal article

Cuttaz EA, Chapman CAR, Syed O, Goding JA, Green RAet al., 2021, Stretchable, fully polymeric electrode arrays for peripheral nerve stimulation, Advanced Science, Vol: 8, Pages: 1-14, ISSN: 2198-3844

There is a critical need to transition research level flexible polymer bioelectronics toward the clinic by demonstrating both reliability in fabrication and stable device performance. Conductive elastomers (CEs) are composites of conductive polymers in elastomeric matrices that provide both flexibility and enhanced electrochemical properties compared to conventional metallic electrodes. This work focuses on the development of nerve cuff devices and the assessment of the device functionality at each development stage, from CE material to fully polymeric electrode arrays. Two device types are fabricated by laser machining of a thick and thin CE sheet variant on an insulative polydimethylsiloxane substrate and lamination into tubing to produce pre‐curled cuffs. Device performance and stability following sterilization and mechanical loading are compared to a state‐of‐the‐art stretchable metallic nerve cuff. The CE cuffs are found to be electrically and mechanically stable with improved charge transfer properties compared to the commercial cuff. All devices are applied to an ex vivo whole sciatic nerve and shown to be functional, with the CE cuffs demonstrating superior charge transfer and electrochemical safety in the biological environment.

Journal article

Aregueta-Robles UA, Enke YL, Carter PM, Green RA, Poole-Warren LAet al., 2020, Subthreshold Electrical Stimulation for Controlling Protein-Mediated Impedance Increases in Platinum Cochlear Electrode, IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, Vol: 67, Pages: 3510-3520, ISSN: 0018-9294

Journal article

Vallejo-Giraldo C, Genta M, Cauvi O, Goding J, Green Ret al., 2020, Hydrogels for 3D neural tissue models: understanding cell-material interactions at a molecular level., Front Bioeng Biotechnol, Vol: 8, Pages: 1-14, ISSN: 2296-4185

The development of 3D neural tissue analogs is of great interest to a range of biomedical engineering applications including tissue engineering of neural interfaces, treatment of neurodegenerative diseases and in vitro assessment of cell-material interactions. Despite continued efforts to develop synthetic or biosynthetic hydrogels which promote the development of complex neural networks in 3D, successful long-term 3D approaches have been restricted to the use of biologically derived constructs. In this study a poly (vinyl alcohol) biosynthetic hydrogel functionalized with gelatin and sericin (PVA-SG), was used to understand the interplay between cell-cell communication and cell-material interaction. This was used to probe critical short-term interactions that determine the success or failure of neural network growth and ultimately the development of a useful model. Complex primary ventral mesencephalic (VM) neural cells were encapsulated in PVA-SG hydrogels and critical molecular cues that demonstrate mechanosensory interaction were examined. Neuronal presence was constant over the 10 day culture, but the astrocyte population decreased in number. The lack of astrocytic support led to a reduction in neural process outgrowth from 24.0 ± 1.3 μm on Day 7 to 7.0 ± 0.1 μm on Day 10. Subsequently, purified astrocytes were studied in isolation to understand the reasons behind PVA-SG hydrogel inability to support neural network development. It was proposed that the spatially restrictive nature (or tight mesh size) of PVA-SG hydrogels limited the astrocytic actin polymerization together with a cytoplasmic-nuclear translocation of YAP over time, causing an alteration in their cell cycle. This was confirmed by the evaluation of p27/Kip1 gene that was found to be upregulated by a twofold increase in expression at both Days 7 and 10 compared to Day 3, indicating the quiescent stage of the astrocytes in PVA-SG hydrogel. Cell migration was further studied by th

Journal article

Novikov A, Goding J, Chapman C, Cuttaz E, Green RAet al., 2020, Stretchable bioelectronics: Mitigating the challenges of the percolation threshold in conductive elastomers, APL Materials, Vol: 8, Pages: 101105-101105

Journal article

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