The Challenge: Delivering Water-Soluble Proteins to the Ocular Surface
The ocular surface is rich in a diverse array of proteins, each playing a role in maintaining structural integrity, protecting against infection, lubricating the eye, and regulating tear production. Macromolecules such as lumican, keratocan, and mimecan reside in the corneal stroma and help preserve corneal transparency. When the expression of these proteins is suppressed, the result is ocular surface dysfunction.
Protein, peptide, and nucleic acid therapies offer a way to address ocular surface disorders through targeted pharmacologic action. The difficulty is in delivery. These therapies are administered primarily as eye drops, which are rapidly cleared from the ocular surface by tear turnover and naso-lacrimal drainage. This rapid wash-out forces frequent dosing, often four to six times per day, to maintain a therapeutic effect.
Protein solutions also present a stability problem. They are inherently unstable over the long term, and some commercial protein eye drops must be stored frozen to preserve activity. For teams designing a protein-based ocular product, the practical goal is clear: a delivery system that holds the protein intact at physiological temperature and pH, releases functional protein over multiple days, remains stable in storage, and can be self-administered without clinical intervention.
A Nanostructured Insert Approach: The NanoM™ Wafer
To address the residence time and stability limitations of drop-based dosing, Integral BioSystems developed the NanoM™ Wafer, a protein-containing nanostructured ocular insert. The NanoM Wafer ocular insert is placed into the lower conjunctival fornix in an elastomeric dry form, where it hydrates in situ and forms an adherent film against the conjunctival mucosa.
The wafer is fabricated by a proprietary process that produces a layered, intercalated microstructure. This architecture is what enables controlled encapsulation and sustained release of proteins from the matrix. The insert is designed to be matched in flexural modulus to the ocular conjunctival fornix, which supports biocompatibility and comfort at the placement site.
Key design and functional attributes of the NanoM™ Wafer include:
- Wafer thickness in the range of 150 to 250 microns
- Hydration of approximately 110 to 125 percent in the hydrated state
- Strain at break greater than 300 mPa, indicating elastomeric mechanical behavior
- Protein encapsulation tunable from approximately 3 to 50 micrograms per milligram, adjustable to the dosing requirement
- Residual solvent below 0.5 percent following vacuum drying
- Placement in the lower conjunctival fornix in dry form, with no clinical intervention required for application
Because the wafer is biodegradable and self-administered, it removes the need for surgical placement or removal, supporting patient compliance in a multi-day therapy regimen.
Research Design and Methods
The research presented at the 2025 ARVO Annual Meeting (Poster 1777 – B0512) tested the hypothesis that proteins across a range of molecular weights can be encapsulated intact within the NanoM™ Wafer, retaining greater than 80 percent integrity as measured by size-exclusion chromatography, and released as intact protein at 37°C and pH 7.4 for more than 14 days.
Three model proteins were studied across distinct molecular weight ranges: 10 to 30 kDa, 60 to 70 kDa, and 110 to 125 kDa. NanoM™ Wafer prototypes were fabricated from combinations of polymers and excipients compatible with the proteins. Wafer thickness was measured using a Mitutoyo screw gauge. Encapsulation was quantified by dissolving 10 mg of dry wafer in an organic solvent to dissolve the polymer while leaving the protein undissolved, removing the dissolved polymer by centrifugation, then drying and reconstituting the protein pellet for concentration analysis. Chromatograms were analyzed for high molecular weight species and monomeric protein content.
Stress-strain studies were performed on a Shimadzu EZ tensile tester to evaluate the elastomeric properties of the wafer. In vitro release was assessed on 10 mg samples at 37°C using a low-volume proprietary method, with time-point samples analyzed by SEC HPLC for released protein. Safety and tolerability were evaluated by assessment of ocular tissue after placement in New Zealand White Rabbits, using the SPOTS scoring system (Eaton et al. 2017). Sterilization was carried out by exposing pre-packaged wafers to cold sterilizing radiation.
Key Findings from the Research
The following results are relevant for teams evaluating sustained release ophthalmic formulation development strategies for protein and biologic therapeutics:
Intact Protein Released at Every Timepoint
SEC HPLC analysis of released protein showed that intact, monomeric protein was recovered at every timepoint across the study. The chromatographic profiles indicated that the encapsulation and release process preserved protein integrity, consistent with the design target of greater than 80 percent integrity. This supports the feasibility of delivering functional protein, rather than degraded or aggregated species, from the NanoM™ matrix.
Sustained Release across Three Molecular Weight Ranges
In vitro release studies demonstrated sustained delivery of all three proteins, spanning the 10 to 30 kDa, 60 to 70 kDa, and 110 to 125 kDa ranges, over the duration of the study at 37°C and pH 7.4. Release was tracked across more than 10 days, with the release rate varying by protein. This indicates that the platform can accommodate biologics of widely different molecular weights, from smaller peptides through to large immunoglobulin-scale molecules.
Terminally Sterilized Wafers Retained Release Performance
Wafers exposed to cold sterilizing radiation in pre-packaged form continued to demonstrate sustained release of proteins across the different molecular weight ranges. The ability to terminally sterilize the insert without compromising release behavior is an important consideration for the regulatory pathway and for commercial-scale manufacturing.
Mechanical Properties Matched to Ocular Tissue
The Young modulus of the hydrated NanoM™ Wafer inserts was found to be comparable to the underlying soft tissue of the conjunctival fornix. Stress-strain testing showed strain at break greater than 300 mPa, and scanning electron micrographs of the cross-section revealed the layered, intercalated microstructure that houses the protein-containing matrix. Matching the flexural modulus of the insert to the placement site supports biocompatibility and patient comfort during wear.
Adherent and Well Tolerated in Vivo
In New Zealand White Rabbits, the NanoM™ Wafer was translucent and adherent to the underlying tissue after placement. Acute tolerability assessment using the SPOTS scoring system showed no redness, hyperemia, discharge, or corneal opacity upon placement of the insert. No adverse effects were noted on the evaluated ocular parameters.
What This Means for Ophthalmic Development Teams
For R&D and formulation teams working on protein, peptide, or nucleic acid ophthalmic compounds, this research highlights several practical considerations:
- Proteins across a broad molecular weight range, from small peptides through to immunoglobulin-scale biologics, can be encapsulated and released as intact, functional protein from a single insert platform.
- Sustained release at physiological temperature and pH reduces reliance on frequent drop-based dosing and the patient compliance burden that comes with it.
- The insert can be terminally sterilized and scaled up, two requirements that often determine whether a delivery technology can progress toward a commercial product.
- Matching the flexural modulus of the wafer to ocular tissue supports biocompatibility and comfort, and the biodegradable design removes the need for surgical placement or removal.
- Beyond ocular surface protein therapy, the same platform can be configured for other indications, including the delivery of drugs for conditions such as glaucoma.
Integral BioSystems’ expertise in drug development services for ophthalmic compounds, combined with the NanoM™ platform, supports programs working with protein therapeutics from early feasibility through process engineering and scale-up.
Read the Full Research
This blog post summarizes key findings from the ARVO 2025 poster by Barman, Bhardwaj, Stanczak, and Ward (Poster 1777 – B0512). To review the complete research, including detailed materials and methods, encapsulation data, stress-strain results, SEM imaging, and in vitro release profiles, download the full poster (PDF).
Explore all Integral BioSystems research on the publications page.
Discuss Your Ophthalmic Formulation Program
Whether you are evaluating sustained release strategies for a protein therapeutic or exploring the NanoM™ platform for a biologic compound, Integral BioSystems can support your program from feasibility through process engineering. Request a formulation consult to discuss your molecule and delivery objectives.