Retinal organoids are tiny 3D models of retinal tissue used in medical and life-science research and are changing how scientists explore eye disease, develop therapies, and evaluate new drugs. However, one persistent challenge has been their unreliable interaction with biomaterial surfaces. Poor attachment or inconsistent cell development limits experimental accuracy and slows progress in regenerative medicine.
A recent study by Marcos et al examined how different surface chemistries influence the behaviour of retinal organoids. Importantly, the research relied on plasma surface treatment using the Henniker HPT-200 system to create and prepare the functionalised surfaces used in the experiments.
This article summarises the challenge, how Henniker’s plasma technology helped, and the key findings relevant to plasma-treated surfaces.
The Challenge: Controlling How Retinal Organoids Behave on Surfaces
For retinal organoids to mature correctly, they must successfully attach to the substrate beneath them and form stable interactions with the material’s surface. In traditional culture conditions, this behaviour is inconsistent due to variations in:
- Surface cleanliness
- Surface energy
- Wettability
- Chemical functional groups
These surface-level differences can dramatically affect:
- How well organoids adhere
- How far their cells migrate
- Whether photoreceptors and ganglion cells develop correctly
- Reproducibility between experiments
To solve this, the research team required a method to create precise, repeatable, chemically defined surfaces. Plasma surface treatment became essential.
How Plasma Surface Treatment Supports Retinal Organoid Success
Plasma surface treatment played a crucial role in enabling the study’s-controlled investigation. Henniker plasma treatment:
Ensured reproducible functionalisation
Creating consistent surface chemistries is vital for organoid research. Plasma activation provides identical surface conditions across every sample.
Improved surface wettability and cell compatibility
The plasma-treated hydroxyl surface, produced directly by the HPT-200, offered improved:
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- Initial attachment
- Cell migration
- Photoreceptor development
- Neurite extension
Enabled reliable downstream chemical grafting
Without plasma-treated substrates, silane-based functionalisation would not bind effectively, undermining the whole experiment.
In essence, plasma surface treatment made the study’scontrolled comparison possible,and the best-performing surface was created entirely by plasma alone.
The Results: Effects of Plasma-Treated and Functionalised Surfaces
1. Organoid Attachment
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- 78% attachment on plasma-treated hydroxyl surfaces
- Lower attachment on chemically less favourable surfaces such as phenyl or methyl
This confirms that plasma-produced-OH surfaces support fast and stable organoid adhesion.
[1] Figure 4. Water contact angle characterization of modified surfaces and respective RO adhesion. Modified (3-aminopropyl) triethoxysilane (NH2), phenyltriethoxysilane (Ph) and chlorotrimethylsilane methyl (─CH3) surfaces WCA measurements compared against a hydroxyl (─OH) control plasma treated glass surface and untreated glass sample. RO initial attachment data (%) provided for each experimental group.
2. Cell Migration and Spreading
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- Hydroxyl (+OH) and amine (+NH₂) surfaces promoted greater migration
- Phenyl surfaces showed poor early interaction
Both plasma-treated and amine-functionalised surfaces created more supportive environments for developing tissue.
[2] Figure 5. RO outgrowth spreading capacity and cell migration on different surface chemistries analysis on Image J. a,c) RO outgrowth and cell migration of an RO on ─Ph surface stained for DAPI (blue, cells nuclei) respectively. Yellow dotted line highlights RO boundary; yellow arrow highlights elongation of neurites away from central mass of RO. Scale bars 500 μm. Plots show a) cell spread area and b) cell migration for ROs after 5, 10, and 15 days of attachment (D20, D25, and D33). Error bars represent standard deviation (SD) with a minimum of n = 3. Statistical analysis against control hydroxyl group (─OH). Significance represented by *p < 0.05 (b) and *p < 0.05, and ***p < 0.001 (b).
3. Photoreceptor Development
Photoreceptors extended longer neurites and occupied larger areas on plasma-treated hydroxyl surfaces.
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- Longest neurite lengths (~1043 μm at D33) were seen on the plasma-treated surface
- Photoreceptor behaviour was strongest on -OH and -NH₂ surfaces
[3] Figure 6. Photoceptors outgrow area and elongation capactiy on differen surfaces analysis Image J. a) PR outgrowth area and c) processes elongation RO on -OH surface stained for CD73 (green, photoreceptors cell membrane) . Yellow dotted line highlights RO boundary; yellow arrow highlights elongation of neurites away from central mass RO. Scale bars represent standard deviation (+SD) with a minium of n = 3. Statistical analysis against control hydroxyl group (-OH). Significance represented by **p <0.05 and ***p<0.001 and * p <0.001 (b).
4. Retinal Ganglion Cells (RGCs)
RGC numbers declined over time, a natural biological process but surface chemistry did not negatively influence survival.
[4] Figure 7. Retinal Ganglion cell numbers analysis. a) Representative image of an RO on ─OH surface stained for BRN3A (red, cell nuclei) fluorescent image used to manually count RGC numbers. Scale bar 100 μm. b) RGC numbers, normalized to RO areas, on different surfaces for ROs after 5, 10, and 15 days of attachment (D20, D25 and D33). Error bars represent standard deviation (SD) with a minimum of n = 3.
Conclusion
The study evidence’s that plasma surface treatment for retinal organoids significantly improves substrate compatibility and biological outcomes. The plasma-treated hydroxyl surface produced via the Henniker HPT-200 delivered:
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- The highest organoid attachment
- Better cell migration
- Stronger photoreceptor development
- Enhanced neurite extension
Plasma activation also enabled the reliable preparation of all chemically modified surfaces tested.
For laboratories working in biomaterials engineering, retinal research, organoid technologies, or regenerative medicine, plasma surface treatment offers a dependable way to enhance cell–material interactions and improve consistency across experiments.
Henniker plasma systems continue to play an important role in supporting cutting-edge biomedical research by providing precise, repeatable surface preparation for advanced cell models.
Readers are referred to the original print, available through the provided DOI link, or click the link below for further details on the Henniker Plasma HPT-200.
[1] Figure 4. Water contact angle characterization of modified surfaces and respective RO adhesion. Selective Promotion of Retinal Organoid Attachment andDifferentiation by Amine- and Hydroxyl-Modified Surfaces - Advanced NanoBiomed Research.
[2] Figure 5. RO outgrowth spreading capacity and cell migration on different surface chemistries analysis. Selective Promotion of Retinal Organoid Attachment andDifferentiation by Amine- and Hydroxyl-Modified Surfaces - Advanced NanoBiomed Research.
[3 ]Figure 6. Photoceptors outgrow area and elongation capactiy on differen surfaces analysis. Selective Promotion of Retinal Organoid Attachment andDifferentiation by Amine- and Hydroxyl-Modified Surfaces - Advanced NanoBiomed Research.
[4] Figure 7. Retinal Ganglion cell numbers analysis. Selective Promotion of Retinal Organoid Attachment andDifferentiation by Amine- and Hydroxyl-Modified Surfaces - Advanced NanoBiomed Research.
Luis Marcos, Charlie Hall, Eric J. Hill, Samantha L. Wilson, Paul Roach
