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Investigating Microinvasive Intra-Ocular Biopsy
Jared Ching1,2, Shohei Kitahata1, Hinako Ichikawa1
1Department of Ophthalmology and Microtechnology, Yokohama City University Medical Centre, Yokohama, Japan.
Background:
Current minimally invasive methods of intraocular biopsy are confined to small gauge (G) needles and subretinal cannulae that can be prone to wound leakage at the biopsy site. We investigate the role of microneedles with internal diameters as small as 49G for intraocular biopsy in the posterior and anterior segments.
Methods:
Human uveal melanoma (UM 92-1) and retinoblastoma (Y79) cancer cell lines were aspirated using microneedles of different sizes with a vitrectomy set up, and cell viability was analysed. Suspensions of cancer cells with fluorescent microbeads were injected into the subretinal space of fresh ex vivo porcine eyes before simulating biopsy with microneedle retinal puncture, followed by imaging with optical coherence tomography (OCT) and histology. Anterior chamber puncture was performed with microneedles and imaged with anterior segment OCT and examined for aqueous leakage.
Results:
We find that microneedles can aspirate ocular cancer cells, both retinoblastoma and uveal melanoma, in vitro and retain a high level of cell viability, 72.83% (49G) compared to 97.00% (25G vitrector) in UM 92-1. Using an ex vivo porcine model, we find that a 49G microneedle creates a self-sealing retinal wound that does not reflux microbeads of 200 nm in diameter. Further, we find that anterior chamber puncture with a microneedle via a corneal paracentesis results in no evidence of an aqueous leak (0%) compared to a leakage rate of 100% and 66% when using a 30G and 34G needle, respectively.
Conclusion:
A microinvasive approach to biopsy intraocular specimens is feasible, warranting further in vivo studies.
Insights
Microneedles show promise for minimally invasive intraocular biopsy, successfully aspirating ocular cancer cells with high viability. These microneedles create self-sealing wounds, reducing leakage in anterior and posterior segments.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Surgical Innovation
Background:
- Current intraocular biopsy methods using small gauge needles and subretinal cannulae risk wound leakage.
- Investigating microneedles with internal diameters as small as 49G for improved intraocular biopsy.
- Focus on both posterior and anterior segments of the eye.
Purpose of the Study:
- To evaluate the feasibility of using microneedles for intraocular biopsy.
- To assess cell viability after aspiration with microneedles.
- To determine the wound sealing properties of microneedle punctures in ocular tissues.
Main Methods:
- Aspiration of human uveal melanoma and retinoblastoma cell lines using various microneedle sizes.
- In vitro analysis of cell viability post-aspiration.
- Ex vivo porcine eye model for simulating retinal puncture and anterior chamber puncture with microneedles.
- Optical coherence tomography (OCT) and histology for imaging and analysis.
Main Results:
- Microneedles successfully aspirated ocular cancer cells (retinoblastoma, uveal melanoma) with high cell viability (72.83% for 49G).
- A 49G microneedle created a self-sealing retinal wound in ex vivo porcine eyes, preventing reflux of 200nm microbeads.
- Anterior chamber puncture with microneedles resulted in 0% aqueous leakage, significantly outperforming larger gauge needles.
Conclusions:
- A microinvasive approach using microneedles for intraocular biopsy is feasible.
- Microneedles offer a promising alternative to current methods, minimizing leakage.
- Further in vivo studies are warranted to validate these findings.
