scholarly journals Self-Expanding Anchors for Stabilizing Percutaneously Implanted Microdevices in Biological Tissues

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 404
Author(s):  
Sharath Bhagavatula ◽  
Devon Thompson ◽  
Christine Dominas ◽  
Irfanullah Haider ◽  
Oliver Jonas

Percutaneously implanted miniaturized devices such as fiducial markers, miniaturized sensors, and drug delivery devices have an important and expanding role in diagnosing and treating a variety of diseases. However, there is a need to develop and evaluate anchoring methods to ensure that these microdevices remain secure without dislodgement, as even minimal migration within tissues could result in loss of microdevice functionality or clinical complications. Here we describe two anchoring methods made from biocompatible materials: (1) a self-expanding nitinol mesh anchor and (2) self-expanding hydrogel particles contained within pliable netting. We integrate these anchors into existing drug-screening microdevices and experimentally measure forces required to dislodge them from varying tissues. We report similar dislodgement forces of 738 ± 37, 707 ± 40, 688 ± 29, and 520 ± 28 mN for nitinol-anchored microdevices, and 735 ± 98, 702 ± 46, 457 ± 47, and 459 ± 39 mN for hydrogel-anchored microdevices in liver, kidney, fat, and muscle tissues, respectively—significantly higher compared with 13 ± 2, 15 ± 3, 15 ± 2, and 15 ± 3 mN for non-anchored microdevices (p < 0.001 in all tissues). The anchoring methods increased resistance to dislodgement by a factor of 30–50× in all tissues, did not increase the required needle gauge for insertion, and were compatible with percutaneous implantation and removal. These results indicate that anchoring significantly improves microdevice stability and should reduce migration risk in a variety of biological tissues.

2011 ◽  
Vol 84 (4) ◽  
pp. 1306-1313 ◽  
Author(s):  
Sema Ekici ◽  
Pinar Ilgin ◽  
Sultan Butun ◽  
Nurettin Sahiner

2020 ◽  
Vol 26 ◽  
Author(s):  
John Chen ◽  
Andrew Martin ◽  
Warren H. Finlay

Background: Many drugs are delivered intranasally for local or systemic effect, typically in the form of droplets or aerosols. Because of the high cost of in vivo studies, drug developers and researchers often turn to in vitro or in silico testing when first evaluating the behavior and properties of intranasal drug delivery devices and formulations. Recent advances in manufacturing and computer technologies have allowed for increasingly realistic and sophisticated in vitro and in silico reconstructions of the human nasal airways. Objective: To perform a summary of advances in understanding of intranasal drug delivery based on recent in vitro and in silico studies. Conclusion: The turbinates are a common target for local drug delivery applications, and while nasal sprays are able to reach this region, there is currently no broad consensus across the in vitro and in silico literature concerning optimal parameters for device design, formulation properties and patient technique which would maximize turbinate deposition. Nebulizers are able to more easily target the turbinates, but come with the disadvantage of significant lung deposition. Targeting of the olfactory region of the nasal cavity has been explored for potential treatment of central nervous system conditions. Conventional intranasal devices, such as nasal sprays and nebulizers, deliver very little dose to the olfactory region. Recent progress in our understanding of intranasal delivery will be useful in the development of the next generation of intranasal drug delivery devices.


2019 ◽  
Vol 16 (3) ◽  
pp. 258-265
Author(s):  
Kei Takahashi ◽  
Tomomi Masuda ◽  
Mitsunori Harada ◽  
Tadashi Inoue ◽  
Shinsuke Nakamura ◽  
...  

Objective: This study aimed to examine whether DC101 (anti-VEGFR2 antibody)- modified micelles have applications as novel drug delivery devices, which allow small molecule antiangiogenic agents to deliver to angiogenic sites on a murine laser-induced choroidal neovascularization (CNV) model. Materials and Method: CNV was induced by photocoagulation on the unilateral eye of each mouse under anesthesia. Immediately after laser coagulation, E7974-loaded DC101-modified micelles and motesanib-loaded DC101-modified micelles were intravitreally administrated. Two weeks after photocoagulation, CNV was visualized using fluorescein-conjugated dextran (MW=2,000 kDa), and the CNV area was measured in retinal pigment epithelium (RPE)-choroidal flat mounts. Results: Intravitreal administration of both DC101-modified micelles loaded with E7974 at 2 µM and motesanib at 2 µM significantly reduced CNV area in the murine laser-induced CNV model at a clearly lower concentration than the effective dose of each agent. Conclusion: These results suggest that DC101-modified micelle might be effective drug carrier system for treating CNV and other ocular angiogenic diseases.


Author(s):  
Jiawei Wang ◽  
Yu Zhang ◽  
Niloofar Heshmati Aghda ◽  
Amit Raviraj Pillai ◽  
Rishi Thakkar ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mary Beth Wandel ◽  
Craig A. Bell ◽  
Jiayi Yu ◽  
Maria C. Arno ◽  
Nathan Z. Dreger ◽  
...  

AbstractComplex biological tissues are highly viscoelastic and dynamic. Efforts to repair or replace cartilage, tendon, muscle, and vasculature using materials that facilitate repair and regeneration have been ongoing for decades. However, materials that possess the mechanical, chemical, and resorption characteristics necessary to recapitulate these tissues have been difficult to mimic using synthetic resorbable biomaterials. Herein, we report a series of resorbable elastomer-like materials that are compositionally identical and possess varying ratios of cis:trans double bonds in the backbone. These features afford concomitant control over the mechanical and surface eroding degradation properties of these materials. We show the materials can be functionalized post-polymerization with bioactive species and enhance cell adhesion. Furthermore, an in vivo rat model demonstrates that degradation and resorption are dependent on succinate stoichiometry in the elastomers and the results show limited inflammation highlighting their potential for use in soft tissue regeneration and drug delivery.


2021 ◽  
Vol 331 ◽  
pp. 503-514
Author(s):  
Ilin Sadeghi ◽  
James Byrne ◽  
Rameen Shakur ◽  
Robert Langer

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