Near infrared-light drug-delivery materials for ocular implants
Project ID: PN-III-P1-1.1-TE-2019-0538


The overall goal of the OCUMATER project was to develop competitive near infrared-light responsive hydrogel materials based on the poli(2-izopropenil-2-oxazolina) platform, using an accessible yet versatile approach, to be used for on-demand drug delivery bioresorbable ocular devices. The main goal of the project has been achieved, and the degree of achievement of the specific objectives until August 31, 2022, is 100% according to the funding request of the young teams project, considering the associated risks.

1. The specific objectives of the project:

The first objective aimed to optimize the crosslinking protocols of PiPOx with dicarboxylic amino/ hydroxy acids to obtain degradable hydrogel materials with balanced properties. The possibility of mixing all the ingredients in a one-pot strategy towards drug formulations was tested.
This objective corresponds to a level of technological maturity 1 (Experimental Concept) which derived from the previously published results of our group. To increase the degree of impact on the research results described in the funding request, but also for biological and ecological considerations, the organic solvents previously used in syntheses were replaced with water, and the working temperature was lowered to 60 °C to avoid degradation of the tested drug and the thermal oxidation of amino acids (crosslinkers). Within this objective, the mixing of all ingredients was optimized in one-pot synthesis to obtain drug formulations. The physico-chemical properties, but also the mechanical properties of the resulting hydrogels were optimized. In this context, the determination of the chemical stability of PiPOx under physiological conditions was also carried out, in order to evaluate the applicability of the starting polymer in the biomedical context, which resulted in a first ISI scientific paper published in a specialized journal from ACS. Another scientific paper will be submitted for publication based on the experimental concept.

The second objective aimed to test and validate the light-assisted protocol for NIR-RHM towards attaining remote control on the drug-release profiles.
This objective corresponds to a technological maturity level 2 (Experimental Models). Based on the previous experience in the characterization of light-sensitive functional materials, the response to the light stimulus of the developed hydrogels was optimized, obtaining the release of the drug on demand but also reversibility within the investigated systems. In this context, a review paper was elaborated on the topic of the project to emphasize the relevance of using azobenzene derivatives sensitive to red light in the construction of biodegradable materials that release drugs for emerging fields such as photopharmacology. A second scientific paper was published in a specialized journal from Nature with high FI.

The third objective aims to validate the drug-release performance of the NIR-RHM in relevant in vitro environments (i.e. simulated body fluids, simulated ocular fluids).
This objective corresponds to a technological maturity level 3 (Functional Models). Based on the previous experience in investigating stability and degradability properties, hydrogels with slow or accelerated degradable profile were obtained depending on the nature of the crosslinker used. This aspect is important because it dictates the resorbable character of the implant over time. Within this objective, the interaction of the raw materials, the intermediates, and the final hydrogels with different cell lines was determined, which contributed to a differentiation of the level of cytotoxicity in all experimental stages. In this context, the experimental lab technology to produce PHOTOSENSITIVE AND DEGRADABLE POLYMERIC HYDROGELS BASED ON POLY(2-ISOPROPENYL-2-OXAZOLINE) AND THERAPEUTIC AGENTS was realized. To protect intellectual property rights, a national patent application was submitted to OSIM.

The fourth objective consisted in disseminating the results of the project and protecting intellectual property, integrated into a managerial plan focused on scientific risk management.
Within this final objective, the following aspects related to the project were considered: (i) administrative and scientific risks that were accompanied by mitigation solutions in a complete management plan; (ii) intellectual property protection through a national patent claim; and (iii) by dissemination of the preliminary scientific results at the international level consisting of 3 ISI rated scientific papers with IF > 4, and 4 scientific communications at international conferences.

2. Activities:

Stage I/2020
Activity 1.1 Protocols for the preparation of reference materials and physico-chemical characterization methods used in obtaining hydrogels have been established. (2020)

Stage II/2021
Activity 2.1. Protocols for the preparation of reference hydrogels and physico-chemical characterization methods have been optimized. (2021)
Activity 2.2. Protocols for the preparation of photosensitive hydrogels and physico-chemical characterization methods have been established. (2021)
Activity 2.3. The response time to the near infrared light of the reference materials was investigated. (2021)
Activity 2.4. The near-infrared light response time of photosensitive hydrogels was investigated. (2021)
Activity 2.5. The protocols for obtaining the reference hydrogels and the photosensitive hydrogels have been perfected. (2021)
Activity 2.6. Dissemination through international communication and publication of preliminary results has been successfully accomplished. (2021)

Stage III/2022
Activity 3.1. The degradability of reference and photosensitive hydrogels was investigated. (2022)
Activity 3.2. The drug-release of hydrogels in the presence and absence of light stimulus was investigated and optimized. (2022)
Activity 3.3. Cytotoxicity evaluation of the reference and photosensitive hydrogels was investigated. (2022)
Activity 3.4. Dissemination of the results by international communication and publishing has been successfully accomplished. (2022)