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Gil B, Hall TAG, Freeman DME, Ming D, Kechagias S, Nabilla S, Cegla F, van Arkel RJ. Wireless implantable bioelectronics with a direct electron transfer lactate enzyme for detection of surgical site infection in orthopaedics. Biosens Bioelectron 2024; 263:116571. [PMID: 39047650 DOI: 10.1016/j.bios.2024.116571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 07/09/2024] [Accepted: 07/11/2024] [Indexed: 07/27/2024]
Abstract
Periprosthetic infection is one of the most devastating complications following orthopaedic surgery. Rapid detection of an infection can change the treatment pathway and improve outcomes for the patient. In here, we propose a miniaturized lactate biosensor developed on a flexible substrate and integrated on a small-form bone implant to detect infection. The methods for lactate biosensor fabrication and integration on a bone implant are fully described within this study. The system performance was comprehensively electrochemically characterised, including with L-lactate solutions prepared in phosphate-buffered saline and culture medium, and interferents such as acetaminophen and ascorbic acid. A proof-of-concept demonstration was then conducted with ex vivo ovine femoral heads incubated with and without exposure to Staphylococcus epidermidis. The sensitivity, current density and limit-of-detection levels achieved by the biosensor were 1.25 μA mM-1, 1.51 μA.M-1.mm-2 and 66 μM, respectively. The system was insensitive to acetaminophen, while sensitivity to ascorbic acid was half that of the sensitivity to L-lactate. In the ex vivo bone model, S. epidermidis infection was detected within 5 h of implantation, while the control sample led to no change in the sensor readings. This pioneering work demonstrates a pathway to improving orthopaedic outcomes by enabling early infection diagnosis.
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Affiliation(s)
- Bruno Gil
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, UK.
| | - Thomas A G Hall
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, UK
| | - David M E Freeman
- Centre for Antimicrobial Optimisation, Imperial College London, Room 7S5, Commonwealth Building, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK; Department of Infectious Disease, School of Medicine, St Mary's Hospital, Imperial College London, Praed Street, London, W2 1NY, UK
| | - Damien Ming
- Centre for Antimicrobial Optimisation, Imperial College London, Room 7S5, Commonwealth Building, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK; Department of Infectious Disease, School of Medicine, St Mary's Hospital, Imperial College London, Praed Street, London, W2 1NY, UK
| | - Stylianos Kechagias
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, UK
| | - Sasza Nabilla
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, UK
| | - Frederic Cegla
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, UK
| | - Richard J van Arkel
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, UK.
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Shen TW, Tsai MC, Chen TM, Chang CC. Photoacoustic method for measuring the elasticity of polydimethylsiloxane at various mixing ratios. Heliyon 2024; 10:e31726. [PMID: 38841497 PMCID: PMC11152934 DOI: 10.1016/j.heliyon.2024.e31726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 05/19/2024] [Accepted: 05/21/2024] [Indexed: 06/07/2024] Open
Abstract
Measuring elasticity without physical contact is challenging, as current methods often require deconstruction of the test sample. This study addresses this challenge by proposing and testing a photoacoustic effect-based method for measuring the elasticity of polydimethylsiloxane (PDMS) at various mixing ratios, which may be applied on the wide range of applications such as biomedical and optical fields. A dual-light laser source of the photoacoustic (PA) system is designed, employing cross-correlation signal processing techniques. The platform systems and a mathematical model for performing PDMS elasticity measurements are constructed. During elasticity detection, photoacoustic signal features, influenced by hardness and shapes, are analyzed using cross-correlation calculations and phase difference detection. Results from phantom tests demonstrate the potential of predicting Young's modulus using the cross-correlation method, aligning with the American Society for Testing and Materials (ASTM) standard samples. However, accuracy may be affected by mixed materials and short tubes. Normalization or calibration of signals is suggested for aligning with Young's coefficient.
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Affiliation(s)
- Tsu-Wang Shen
- Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, ROC
- Master's Program Biomedical Informatics and Biomedical Engineering, Feng Chia University, Taichung, Taiwan, ROC
| | - Ming-Chun Tsai
- Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, ROC
| | - Ting-Mao Chen
- Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, ROC
| | - Chi-Chang Chang
- School of Medical Informatics, Chung Shan Medical University & IT Office, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC
- Department of Information Management, Ming Chuan University, Taoyuan, Taiwan, ROC
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Chen ZT, Lee BS, Tu TH, Chan YT, Chang CC. Covalent bonding of quaternary ammonium compounds and zwitterionic polymer functional layers on polydimethylsiloxane against Escherichia Coli adhesion. J Biomater Appl 2024; 38:772-783. [PMID: 38058117 DOI: 10.1177/08853282231219063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
Quaternary ammonium compounds (QACs) are recognized by the World Health Organization as a useful disinfectant against microbes. The synergistic effect of zwitterionic polymers with QACs as antimicrobial agents rather than QACs alone is yet to be investigated. A potential strategy is the use of covalent bonding to halt the release of minute antibacterials and a hierarchy of functional layers to detain and annihilate microbes. The strategy was tested on a polydimethylsiloxane (PDMS) surface on which quaternized poly(2-dimethylaminoethyl methacrylate) (qDMA+) and sulfobetaine (SBMA) were hierarchically functionalized. Attenuated total reflectance Fourier transform infrared analysis confirmed the quaternization of DMA to qDMA+, grafting of qDMA + on PDMS (PDMS-qDMA+), and grafting of the SBMA overlayer on PDMS-qDMA+ (PDMS-qDMA+-SB). Contact angle measurement showed that PDMS-qDMA + exhibited the lowest contact angle (26.2 ± 2.9°) compared with the hydrophobic PDMS (115.2 ± 1.6°), but that of PDMSqDMA+-SB increased to 56.3 ± 1.3°. The Escherichia coli survival count revealed that PDMS-qDMA+ and PDMS-qDMA+-SB exhibited significantly greater bactericidal ability than PDMS. Confocal laser scanning microscopy revealed fewer dead bacteria on PDMS-qDMA+-SB than on PDMS-qDMA+. Scanning electron microscopy demonstrated that E. coli was disintegrated on the functionalized surface via dual-end cell lysis. To the best of our knowledge, this is the first observation of this type of process. The results confirmed the potent antibacterial and cell disruption activities of the qDMA+ and SBMA modified PDMS surface.
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Affiliation(s)
- Zi-Ti Chen
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Bor-Shiunn Lee
- Graduate Institute of Oral Biology, School of Dentistry, National Taiwan Universityand National Taiwan University Hospital, Taipei, Taiwan
| | - Tsung-Han Tu
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Yi-Tsu Chan
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Che-Chen Chang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
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