3D‐Bioprinted Phantom with Human Skin Phototypes for Biomedical Optics

Yim, Wonjun; Zhou, Jiajing; Sasi, Lekshmi; Zhao, Jiayu; Yeung, Justin; Cheng, Yong; Jin, Zhicheng; Johnson, W. T.; Xu, Min; Palma‐Chavez, Jorge; Fu, Lei; Qi, Baiyan; Retout, Maurice; Shah, Naseem; Bae, Jinhye; Jokerst, Jesse V.

doi:10.1002/adma.202305227

Cited by 2 publications

(3 citation statements)

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“…The introduction of 1% w/v SDS (above CMC) to coacervates is twofold: (i) it breaks the ion-pairing interactions and disassembles the coacervates, 29 and (ii) it minimizes dye-dye stacking interactions and favors its monomeric state. 38,46 The absorbance peak wavelength of Cy5.5 in coacervates blue-shifts from 687 nm for the monomeric dye to 677 nm, indicating strong intermolecular interactions of Cy5.5. 44 This shift is accompanied by intensity reductions of the hypochromic peak and peak broadening.…”

Section: Figure 4amentioning

confidence: 99%

Understanding enzyme kinetics on coacervate as a substrate hub

Jin,

Jokerst

2024

Colloidal Nanoparticles for Biomedical Applications XIX

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There remains a gap in understanding the enzyme interactions with the coacervate as a substrate hub. Here, we study how the hydrophobicity nature of coacervate affects the interactions of the embedded substrate with a protease. We design oligopeptide-based coacervates that comprise an anionic Asp-peptide (D10) and a cationic Arg-peptide (R5R5) with a proteolytic cleavage site. The coacervates dissolve when exposed to the main protease. We exploit the condensed structure, implement a self-quenching mechanism, and characterize enzyme kinetics with Cy5.5-labeled peptides. The determined specificity constant is 5,817 M -1 s -1 and is similar to that of the free substrate. We further show that the enzyme kinetics depend on the amount of dye incorporated into the coacervates. Our work presents a simple design for coacervates with tuned bioactivities and provides insights into the kinetics between the enzyme and coacervates as a substrate hub.

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Section: Figure 4amentioning

confidence: 99%

Understanding enzyme kinetics on coacervate as a substrate hub

Jin,

Jokerst

2024

Colloidal Nanoparticles for Biomedical Applications XIX

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“…A few studies have begun to emerge that examine skin tone measurement bias in PAI 27 – 30 Higher Fitzpatrick skin type grading was shown to reduce PAI signal-to-noise ratio deep in the tissue and introduced biases in the estimated blood oxygenation 27 – 30 An empirical calibration scheme has been proposed to correct these biases 29 .…”

Section: Introductionmentioning

confidence: 99%

“… – 30 Higher Fitzpatrick skin type grading was shown to reduce PAI signal-to-noise ratio deep in the tissue and introduced biases in the estimated blood oxygenation 27 – 30 An empirical calibration scheme has been proposed to correct these biases 29 . These early studies highlight the key challenges associated with varying skin tones in PAI, how we measure skin tone, and how we develop fluence compensation schemes.…”

Section: Introductionmentioning

confidence: 99%

Effects of skin tone on photoacoustic imaging and oximetry

Else,

Hacker,

Gröhl

et al. 2023

J. Biomed. Opt.

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. Significance Photoacoustic imaging (PAI) provides contrast based on the concentration of optical absorbers in tissue, enabling the assessment of functional physiological parameters such as blood oxygen saturation ( ). Recent evidence suggests that variation in melanin levels in the epidermis leads to measurement biases in optical technologies, which could potentially limit the application of these biomarkers in diverse populations. Aim To examine the effects of skin melanin pigmentation on PAI and oximetry. Approach We evaluated the effects of skin tone in PAI using a computational skin model, two-layer melanin-containing tissue-mimicking phantoms, and mice of a consistent genetic background with varying pigmentations. The computational skin model was validated by simulating the diffuse reflectance spectrum using the adding-doubling method, allowing us to assign our simulation parameters to approximate Fitzpatrick skin types. Monte Carlo simulations and acoustic simulations were run to obtain idealized photoacoustic images of our skin model. Photoacoustic images of the phantoms and mice were acquired using a commercial instrument. Reconstructed images were processed with linear spectral unmixing to estimate blood oxygenation. Linear unmixing results were compared with a learned unmixing approach based on gradient-boosted regression. Results Our computational skin model was consistent with representative literature for in vivo skin reflectance measurements. We observed consistent spectral coloring effects across all model systems, with an overestimation of and more image artifacts observed with increasing melanin concentration. The learned unmixing approach reduced the measurement bias, but predictions made at lower blood still suffered from a skin tone-dependent effect. Conclusion PAI demonstrates measurement bias, including an overestimation of blood , in higher Fitzpatrick skin types. Future research should aim to characterize this effect in humans to ensure equitable application of the technology.

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3D‐Bioprinted Phantom with Human Skin Phototypes for Biomedical Optics

Cited by 2 publications

References 0 publications

Understanding enzyme kinetics on coacervate as a substrate hub

Understanding enzyme kinetics on coacervate as a substrate hub

Effects of skin tone on photoacoustic imaging and oximetry

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