Spatially resolved diffuse imaging for high‐speed depth estimation of jet injection

Brennan, Kieran A.; Ruddy, Bryan P.; Nielsen, Poul M. F.; Taberner, Andrew J.

doi:10.1002/jbio.201900205

Cited by 3 publications

(2 citation statements)

References 23 publications

(24 reference statements)

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“…129 Spatially-resolved diffuse imaging (SRDI) is a variation of DOI that involves recovering the optical parameters from the surface light profile produced by a single source in the tissue. This technique allowed the estimation of penetration depth of high-speed jet injections in ex vivo porcine skin 134 (more details about jet injection method can be found in Section 4). The strategy consisted on coupling the light beam into the fluid jet during penetration allowing the light to travel progressively deeper into the tissue as the jet penetrates (Figure 16b).…”

Section: Diffuse Optical Tomography (Dot)mentioning

confidence: 99%

Challenges and opportunities for small volumes delivery into the skin

Mercuri

Rivas

2021

Biomicrofluidics

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Each individual's skin has its own features, such as strength, elasticity or permeability to drugs, which limits the effectiveness of one-size-fits-all approaches typically found in medical treatments. Therefore, understanding the transport mechanisms of substances across the skin is instrumental for the development of novel minimal invasive transdermal therapies. However, the large difference between transport timescales and length-scales of disparate molecules needed for medical therapies makes it difficult to address fundamental questions. Thus, this lack of fundamental knowledge has limited the efficacy of bioengineering equipment and medical treatments. In this article we provide an overview of the most important microfluidics-related transport phenomena through the skin and versatile tools to study them. Moreover, we provide a summary of challenges and opportunities faced by advanced transdermal delivery methods, such as needle-free jet injectors, microneedles and tattooing, which could pave the way to the implementation of better therapies and new methods.

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Section: Diffuse Optical Tomography (Dot)mentioning

confidence: 99%

Challenges and opportunities for small volumes delivery into the skin

Mercuri

Rivas

2021

Biomicrofluidics

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“…However, the maximum attainable temporal resolution in the present imaging techniques for skin tissue visualization is about 1.5–2 ms [ 47 ], which is not adequate for the real-time visualization of a fluid injected by an NFJIS into the skin tissue matrix. Hence, in majority of the studies, in vitro media like agarose, gelatin, or polyacrylamide gels [ 6 , 7 , 13 , 21 , 36 , 38 , 41 , 43 , 45 , 46 , 48 – 55 ] were used for investigating the dynamic injection characteristics of an NFJIS, while the ex vivo studies were performed via dissection after the injection [ 10 , 11 , 15 , 37 , 38 , 56 – 59 ] or by micro-computed tomography [ 9 ] or X-ray [ 38 , 60 ] imaging techniques. In vitro models are indispensable tools in drug delivery applications for investigating the effect of individual parameters and to tune the independent and alternative parameters.…”

Section: Introductionmentioning

confidence: 99%

Dynamic interaction of injected liquid jet with skin layer interfaces revealed by microsecond imaging of optically cleared ex vivo skin tissue model

et al. 2023

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Background Needle-free jet injection (NFJI) systems enable a controlled and targeted delivery of drugs into skin tissue. However, a scarce understanding of their underlying mechanisms has been a major deterrent to the development of an efficient system. Primarily, the lack of a suitable visualization technique that could capture the dynamics of the injected fluid–tissue interaction with a microsecond range temporal resolution has emerged as a main limitation. A conventional needle-free injection system may inject the fluids within a few milliseconds and may need a temporal resolution in the microsecond range for obtaining the required images. However, the presently available imaging techniques for skin tissue visualization fail to achieve these required spatial and temporal resolutions. Previous studies on injected fluid–tissue interaction dynamics were conducted using in vitro media with a stiffness similar to that of skin tissue. However, these media are poor substitutes for real skin tissue, and the need for an imaging technique having ex vivo or in vivo imaging capability has been echoed in the previous reports. Methods A near-infrared imaging technique that utilizes the optical absorption and fluorescence emission of indocyanine green dye, coupled with a tissue clearing technique, was developed for visualizing a NFJI in an ex vivo porcine skin tissue. Results The optimal imaging conditions obtained by considering the optical properties of the developed system and mechanical properties of the cleared ex vivo samples are presented. Crucial information on the dynamic interaction of the injected liquid jet with the ex vivo skin tissue layers and their interfaces could be obtained. Conclusions The reported technique can be instrumental for understanding the injection mechanism and for the development of an efficient transdermal NFJI system as well.

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Classification of diffuse light emission profiles for distinguishing skin layer penetration of a needle-free jet injection

Brennan

Ruddy

Nielsen

et al. 2019

Biomed. Opt. Express

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In this work, a system is developed for tracking the skin layer to which a needle-free jet injection of fluid has penetrated by incorporating a laser beam into the jet, and measuring the diffuse light emitted from skin tissue. Monitoring the injection in this way offers the ability to improve the reliability of drug delivery with this transdermal delivery method. A laser beam, axially aligned with a jet of fluid, created a distribution of diffuse light around the injection site that varied as the injection progressed. High-speed videography was used to capture the diffuse light emission from laser-coupled jet injections into samples of porcine skin, fat, and muscle. The injection produced a distribution of diffuse light around the injection site that varied as the injection descended. A classifier, trained to distinguish whether the light source was located in the fat or muscle from surface intensity profile measurements, correctly identified the injected layer in 97.2% of the cases when cross-examined against estimates using the light distribution emitted from the side of the sample.

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Spatially resolved diffuse imaging for high‐speed depth estimation of jet injection

Cited by 3 publications

References 23 publications

Challenges and opportunities for small volumes delivery into the skin

Challenges and opportunities for small volumes delivery into the skin

Dynamic interaction of injected liquid jet with skin layer interfaces revealed by microsecond imaging of optically cleared ex vivo skin tissue model

Classification of diffuse light emission profiles for distinguishing skin layer penetration of a needle-free jet injection

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