scholarly journals Wireless implantable sensor for non-invasive, longitudinal quantification of axial strain across rodent long bone defects

2017 ◽  
Author(s):  
Brett S. Klosterhoff ◽  
Keat Ghee Ong ◽  
Laxminarayanan Krishnan ◽  
Kevin M. Hetzendorfer ◽  
Young-Hui Chang ◽  
...  

AbstractBone development, maintenance, and regeneration are remarkably sensitive to mechanical cues. Consequently, mechanical stimulation has long been sought as a putative target to promote endogenous healing after fracture. Given the transient nature of bone repair, tissue-level mechanical cues evolve rapidly over time after injury and are challenging to measure non-invasively. The objective of this work was to develop and characterize an implantable strain sensor for non-invasive monitoring of axial strain across a rodent femoral defect during functional activity. Herein, we present the design, characterization, and in vivo demonstration of the device’s capabilities for quantitatively interrogating physiological dynamic strains during bone regeneration. Ex vivo experimental characterization of the device showed that it exceeded the technical requirements for sensitivity, signal resolution, and electromechanical stability. The digital telemetry minimized power consumption, enabling long-term intermittent data collection. Devices were implanted in a rat 6 mm femoral segmental defect model and after three days, data were acquired wirelessly during ambulation and synchronized to corresponding radiographic videos, validating the ability of the sensor to non-invasively measure strain in real-time. Lastly, in vivo strain measurements were utilized in a finite element model to estimate the strain distribution within the defect region. Together, these data indicate the sensor is a promising technology to quantify local tissue mechanics in a specimen specific manner, facilitating more detailed investigations into the role of the mechanical environment in dynamic skeletal healing and remodeling.

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Brett S. Klosterhoff ◽  
Keat Ghee Ong ◽  
Laxminarayanan Krishnan ◽  
Kevin M. Hetzendorfer ◽  
Young-Hui Chang ◽  
...  

Bone development, maintenance, and regeneration are remarkably sensitive to mechanical cues. Consequently, mechanical stimulation has long been sought as a putative target to promote endogenous healing after fracture. Given the transient nature of bone repair, tissue-level mechanical cues evolve rapidly over time after injury and are challenging to measure noninvasively. The objective of this work was to develop and characterize an implantable strain sensor for noninvasive monitoring of axial strain across a rodent femoral defect during functional activity. Herein, we present the design, characterization, and in vivo demonstration of the device’s capabilities for quantitatively interrogating physiological dynamic strains during bone regeneration. Ex vivo experimental characterization of the device showed that it possessed promising sensitivity, signal resolution, and electromechanical stability for in vivo applications. The digital telemetry minimized power consumption, enabling extended intermittent data collection. Devices were implanted in a rat 6 mm femoral segmental defect model, and after three days, data were acquired wirelessly during ambulation and synchronized to corresponding radiographic videos, validating the ability of the sensor to noninvasively measure strain in real-time. Together, these data indicate the sensor is a promising technology to quantify tissue mechanics in a specimen specific manner, facilitating more detailed investigations into the role of the mechanical environment in dynamic bone healing and remodeling processes.


Author(s):  
Antonio Dell'Osa ◽  
Franco Simini ◽  
Jose C. Felice

Bioimpedance measurements are used increasingly in health applications because bioelectric parameters have been associated with anatomical and physiological properties, thus enabling to distinguish medical conditions. For bone fracture diagnostics, nevertheless, there is no established non-invasive method. Ex vivo studies and In vivo bioimpedance procedures, both invasive and non-invasive, on mammalians long bones are associated with promising results. In this work, out of a total of 568 papers, we reviewd 59 articles that mention long bone integrity by electric properties, be it Bioimpedance Analysis, Electrical Impedance Spectroscopy or Electrical Impedance Tomography. The papers are described in three sections, “Ex vivo measurements”, “In vivo invasive measurements” and “In vivo non-invasive measurements”. This review allows to establish the basics to planning the development of new technology to detect bone fracture via bioimpedance measurements.


2020 ◽  
Vol 56 (4) ◽  
pp. 522-531 ◽  
Author(s):  
D. Basurto ◽  
N. Sananès ◽  
E. Verbeken ◽  
D. Sharma ◽  
E. Corno ◽  
...  

2019 ◽  
Vol 47 (5) ◽  
pp. 1302-1313 ◽  
Author(s):  
Camilla Christensen ◽  
Lotte K. Kristensen ◽  
Maria Z. Alfsen ◽  
Carsten H. Nielsen ◽  
Andreas Kjaer

Abstract Purpose Despite remarkable clinical responses and prolonged survival across several cancers, not all patients benefit from PD-1/PD-L1 immune checkpoint blockade. Accordingly, assessment of tumour PD-L1 expression by immunohistochemistry (IHC) is increasingly applied to guide patient selection, therapeutic monitoring, and improve overall response rates. However, tissue-based methods are invasive and prone to sampling error. We therefore developed a PET radiotracer to specifically detect PD-L1 expression in a non-invasive manner, which could be of diagnostic and predictive value. Methods Anti-PD-L1 (clone 6E11, Genentech) was site-specifically conjugated with DIBO-DFO and radiolabelled with 89Zr (89Zr-DFO-6E11). 89Zr-DFO-6E11 was optimized in vivo by longitudinal PET imaging and dose escalation with excess unlabelled 6E11 in HCC827 tumour-bearing mice. Specificity of 89Zr-DFO-6E11 was evaluated in NSCLC xenografts and syngeneic tumour models with different levels of PD-L1 expression. In vivo imaging data was supported by ex vivo biodistribution, flow cytometry, and IHC. To evaluate the predictive value of 89Zr-DFO-6E11 PET imaging, CT26 tumour-bearing mice were subjected to external radiation therapy (XRT) in combination with PD-L1 blockade. Results 89Zr-DFO-6E11 was successfully labelled with a high radiochemical purity. The HCC827 tumours and lymphoid tissue were identified by 89Zr-DFO-6E11 PET imaging, and co-injection with 6E11 increased the relative tumour uptake and decreased the splenic uptake. 89Zr-DFO-6E11 detected the differences in PD-L1 expression among tumour models as evaluated by ex vivo methods. 89Zr-DFO-6E11 quantified the increase in PD-L1 expression in tumours and spleens of irradiated mice. XRT and anti-PD-L1 therapy effectively inhibited tumour growth in CT26 tumour-bearing mice (p < 0.01), and the maximum 89Zr-DFO-6E11 tumour-to-muscle ratio correlated with response to therapy (p = 0.0252). Conclusion PET imaging with 89Zr-DFO-6E11 is an attractive approach for specific, non-invasive, whole-body visualization of PD-L1 expression. PD-L1 expression can be modulated by radiotherapy regimens and 89Zr-DFO-6E11 PET is able to monitor these changes and predict the response to therapy in an immunocompetent tumour model.


2019 ◽  
Vol 29 ◽  
pp. S160-S161
Author(s):  
P. Mantuano ◽  
A. Mele ◽  
O. Cappellari ◽  
A. Fonzino ◽  
F. Sanarica ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Mdx Mice ◽  

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi124-vi124
Author(s):  
Angelie Rivera-Rodriguez ◽  
Lan Hoang-Minh ◽  
Leyda Marrero-Morales ◽  
Duane Mitchell ◽  
Carlos Rinaldi

Abstract BACKGROUND Adoptive cell therapies (ACT) are strategies being explored to boost the immune response against cancer. ACT cancer immunotherapies are effective against metastatic melanoma, leukemia, and lymphoma, but face challenges in treating other solid tumors, such as in the brain. A critical step for the success of ACT in solid cancers is achieving trafficking and persistence of T-cells at tumor sites. Glioblastoma (GBM) is the most common and aggressive cancer of the central nervous system in adults, with a prognosis of 15-18-month average patient survival after diagnosis. Biomedical imaging is often used to track cell therapies. Magnetic Particle Imaging (MPI) is a novel biomedical imaging modality enabling non-invasive visualization of the distribution of biocompatible superparamagnetic iron oxide (SPIO) tracers. OBJECTIVE Label T-cells with SPIO to non-invasively track adoptive T cell transfer immunotherapy with MPI in the context of brain cancer. METHODS Murine pmel-DsRed T-cells were isolated from the spleen of a transgenic C57BL/6 mouse, and were exposed to different SPIO concentrations ex vivo. Cell viability, phenotype, and cytotoxic function were analyzed to determine if T-cells were affected by the SPIO labeling. Moreover, in vivo experiments were performed in a murine GBM model, and labeled T-cells were injected intravenously and tracked using MPI. RESULTS The SPIO-labeling of T-cells did not affected cell viability, phenotype, or cell cytotoxic function at all tested incubation conditions. The internalized SPIO can be quantified and spatially detected using MPI both in vitro and in vivo. In addition, MPI in vivo tracking shows T-cells accumulation in liver and lungs, as well in the spleen and brain, as showed ex vivo. CONCLUSIONS SPIO-labeling of T-cells did not affected its cytotoxic function and MPI allows for in vivo tracking of adoptively T-cell transfer. MPI will provide better understanding of ACT dynamics to accelerate development of novel treatments.


2020 ◽  
Author(s):  
Fabian C. Herbert ◽  
Olivia Brohlin ◽  
Tyler Galbraith ◽  
Candace Benjamin ◽  
Cesar A. Reyes ◽  
...  

<div> <div> <div> <p>Icosahedral virus-like particles (VLPs) derived from bacteriophages Qβ and PP7 encapsulating small-ultra red fluorescent protein (smURFP) were produced using a versatile supramolecualr capsid dissassemble-reassemble approach. The generated fluorescent VLPs display identical structural properties to their non-fluorescent analogs. Encapsulated smURFP shows indistinguishable photochemical properties to its unencapsulated counterpart, exhibits outstanding stability towards pH, and produces bright in vitro images following phagocytosis by macrophages. In vivo imaging allows biodistribution to be imaged at different time points. Ex vivo imaging of intravenously administered encapsulated smURFP reveleas localization in the liver and </p> </div> </div> <div> <div> <p>kidneys after 2 h blood circulation and substantial elimination constructs as non-invasive in vivo imaging agents. </p> </div> </div> </div>


1981 ◽  
Author(s):  
M Goldman ◽  
D Simpson ◽  
R J Hawker ◽  
Z Drolc ◽  
C N McCollum

Platelet microemboli have been implicated in the aetiology of transient ischaemic attacks and strokes. Current non-invasive diagnostic methods are restricted to assessing blood flow. Arteriography may demonstrate non-occluding atheromatous ulcers but carries a significant morbidity.111-In labelled platelets and gamma camera imaging of diseased carotid vessels have therefore been evaluated.Eight patients proceeding to unilateral carotid endarterectomy received an injection of autologous platelets labelled with 111-In-oxine 48 hours preoperatively. Gamma camera images were taken at 4 and 24 hours. Operative endarterectomy specimens were collected and gamma emissions were measured.The scintigraphic images were independently assessed by two observers. Nine abnormal vessels were identified by platelet accumulation. In 5 cases the observers combined assessment was in complete accord with previous bilateral angiography. Individually each observer identified the symptomatic side in 6 patients. Activity in the endarterectomy specimens measured ex vivo varied from 1.22-84.5 times greater than background activity. The ratio of specimen activity to 5 ml blood samples simultaneously taken varied from 0.017 to 0.360 (mean 0.089).This non-invasive technique allows localisation of platelet activity in the extracranial cerebral circulation. Objective assessment in vivo is hindered by the relatively small amount of activity on the diseased vessels by comparison with circulating blood activity.


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