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Shchapova E, Titov E, Gurkov A, Nazarova A, Borvinskaya E, Timofeyev M. Durability of Implanted Low-Density Polyacrylamide Hydrogel Used as a Scaffold for Microencapsulated Molecular Probes inside Small Fish. Polymers (Basel) 2022; 14:polym14193956. [PMID: 36235907 PMCID: PMC9573640 DOI: 10.3390/polym14193956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 01/19/2023] Open
Abstract
Implantable sensors based on shaped biocompatible hydrogels are now being extensively developed for various physiological tasks, but they are usually difficult to implant into small animals. In this study, we tested the long-term in vivo functionality of pH-sensitive implants based on amorphous 2.7% polyacrylamide hydrogel with the microencapsulated fluorescent probe SNARF-1. The sensor was easy to manufacture and introduce into the tissues of a small fish Danio rerio, which is the common model object in biomedical research. Histological examination revealed partial degradation of the gel by the 7th day after injection, but it was not the case on the 1st day. Using the hydrogel sensor, we were able to trace the interstitial pH in the fish muscles under normal and hypercapnic conditions for at least two days after the implantation. Thus, despite later immune response, amorphous polyacrylamide is fully suitable for preparing implantable sensors for various mid-term physiological experiments on small fishes. The proposed approach can be further developed to create implantable sensors for animals with similar anatomy.
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Affiliation(s)
- Ekaterina Shchapova
- Institute of Biology, Irkutsk State University, 664025 Irkutsk, Russia
- Baikal Research Centre, 664003 Irkutsk, Russia
| | - Evgeniy Titov
- East Siberian Institute of Medical and Ecological Research, 665827 Angarsk, Russia
| | - Anton Gurkov
- Institute of Biology, Irkutsk State University, 664025 Irkutsk, Russia
- Baikal Research Centre, 664003 Irkutsk, Russia
| | - Anna Nazarova
- Institute of Biology, Irkutsk State University, 664025 Irkutsk, Russia
| | | | - Maxim Timofeyev
- Institute of Biology, Irkutsk State University, 664025 Irkutsk, Russia
- Correspondence:
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Unruh RM, Bornhoeft LR, Nichols SP, Wisniewski NA, McShane MJ. Inorganic-Organic Interpenetrating Network Hydrogels as Tissue-Integrating Luminescent Implants: Physicochemical Characterization and Preclinical Evaluation. Macromol Biosci 2022; 22:e2100380. [PMID: 34847287 PMCID: PMC8930476 DOI: 10.1002/mabi.202100380] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/23/2021] [Indexed: 11/07/2022]
Abstract
Sensors capable of accurate, continuous monitoring of biochemistry are crucial to the realization of personalized medicine on a large scale. Great strides have been made to enhance tissue compatibility of long-term in vivo biosensors using biomaterials strategies such as tissue-integrating hydrogels. However, the low level of oxygen in tissue presents a challenge for implanted devices, especially when the biosensing function relies on oxygen as a measure-either as a primary analyte or as an indirect marker to transduce levels of other biomolecules. This work presents a method of fabricating inorganic-organic interpenetrating network (IPN) hydrogels to optimize the oxygen transport through injectable biosensors. Capitalizing on the synergy between the two networks, various physicochemical properties (e.g., swelling, glass transition temperature, and mechanical properties) are shown to be independently adjustable while maintaining a 250% increase in oxygen permeability relative to poly(2-hydroxyethyl methacrylate) controls. Finally, these gels, when functionalized with a Pd(II) benzoporphyrin phosphor, track tissue oxygen in real time for 76 days as subcutaneous implants in a porcine model while promoting tissue ingrowth and minimizing fibrosis around the implant. These findings support IPN networks for fine-tuned design of implantable biomaterials in personalized medicine and other biomedical applications.
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Affiliation(s)
- Rachel M Unruh
- 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX, 77843, USA
| | - Lindsey R Bornhoeft
- 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX, 77843, USA
| | - Scott P Nichols
- Profusa, Inc., 5959 Horton St #450, Emeryville, CA, 94608, USA
| | | | - Michael J McShane
- 5045 Emerging Technologies Building, 3120 TAMU, College Station, TX, 77843, USA
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Khoong YM, Huang X, Gu S, Zan T. Imaging for thinned perforator flap harvest: current status and future perspectives. BURNS & TRAUMA 2021; 9:tkab042. [PMID: 34926708 PMCID: PMC8677592 DOI: 10.1093/burnst/tkab042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/24/2021] [Indexed: 11/12/2022]
Abstract
With advances in anatomical knowledge and technology, increased interest has been directed towards reconstruction with enhanced aesthetic and functional outcomes. A myriad of thinned perforator flap harvest approaches have been developed for this purpose; however, concerns about jeopardizing their vascularity remain. To ensure optimum reconstructive outcome without hampering the flap's microcirculation, it is important to make good use of the existing advanced imaging modalities that can provide clear visualization of perforator branches, particularly in the adipose layer, and an accurate assessment of flap perfusion. Therefore, this review will highlight the imaging modalities that have been utilized for harvesting a thinned perforator flap from these two perspectives, along with future insights into creating both functionally and aesthetically satisfying, yet simultaneously safe, thinned perforator flaps for the best reconstructive outcomes for patients.
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Affiliation(s)
- Yi Min Khoong
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Xin Huang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Shuchen Gu
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Tao Zan
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
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Zavareh AT, Ko B, Roberts J, Elahi S, McShane MJ. A Versatile Multichannel Instrument for Measurement of Ratiometric Fluorescence Intensity and Phosphorescence Lifetime. IEEE ACCESS : PRACTICAL INNOVATIONS, OPEN SOLUTIONS 2021; 9:103835-103849. [PMID: 34858770 PMCID: PMC8635115 DOI: 10.1109/access.2021.3098777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Optical biosensing is being actively investigated for minimally-invasive monitoring of key biomarkers both in vitro and in vivo. However, typical benchtop instruments are not portable and are not well suited to high-throughput, real-time analysis. This paper presents a versatile multichannel instrument for measurement of emission intensity and lifetime values arising from luminescent biosensor materials. A detailed design description of the opto-electronic hardware as well as the control software is provided, elaborating a flexible, user-configurable system that may be customized or duplicated for a wide range of applications. This article presents experimental measurements that prove the in vitro and in vivo functionality of the system. Such tools may be adopted for many research and development purposes, including evaluation of new biosensor materials, and may also serve as prototypes for future miniaturized handheld or wearable devices.
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Affiliation(s)
- Amir Tofighi Zavareh
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Brian Ko
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Jason Roberts
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Sakib Elahi
- Becton Dickinson, Vernon Hills, IL 60061, USA
| | - Michael J McShane
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
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Macrophage Migration Inhibitory Factor-An Innovative Indicator for Free Flap Ischemia after Microsurgical Reconstruction. Healthcare (Basel) 2021; 9:healthcare9060616. [PMID: 34063809 PMCID: PMC8223971 DOI: 10.3390/healthcare9060616] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 12/02/2022] Open
Abstract
(1) Background: Nowadays, the use of microsurgical free flaps is a standard operative procedure in reconstructive surgery. Still, thrombosis of the microanastomosis is one of the most fatal postoperative complications. Clinical evaluation, different technical devices and laboratory markers are used to monitor critical flap perfusion. Macrophage migration inhibitory factor (MIF), a structurally unique cytokine with chemokine-like characteristics, could play a role in predicting vascular problems and the failure of flap perfusion. (2) Methods: In this prospective observational study, 26 subjects that underwent microsurgical reconstruction were observed. Besides clinical data, the number of blood leukocytes, CRP and MIF were monitored. (3) Results: Blood levels of MIF, C-reactive protein (CRP) and leukocytes increased directly after surgery. Subjects that needed surgical revision due to thrombosis of the microanastomosis showed significantly higher blood levels of MIF than subjects without revision. (4) Conclusion: We conclude that MIF is a potential and innovative indicator for thrombosis of the microanastomosis after free flap surgery. Since it is easy to obtain diagnostically, MIF could be an additional tool to monitor flap perfusion besides clinical and technical assessments.
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