| 1. |
- Rafat, Mehrdad, et al.
(författare)
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PEG-PLAmicroparticles for encapsulation and delivery of Tat-EGFP to retinal cells
- 2010
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Ingår i: Biomaterials. - : Elsevier. - 0142-9612 .- 1878-5905. ; 31:12, s. 3414-3421
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Tidskriftsartikel (refereegranskat)abstract
- The efficient and controlled delivery of genes and proteins to retinal cells remains a challenge. In this study, we evaluated polyethylene glycol-polylactic acid (PEG–PLA) microparticles for encapsulation and delivery of a Transactivator of transcription-enhanced green fluorescent protein fusion (Tat-EGFP) to retinal cells. Our main objective was to develop a microparticle system that delivers Tat-EGFP with an initial rapid release (within 24 h) followed by a sustained release. We prepared four different formulations of Tat-EGFP encapsulated PEG–PLA particles to investigate the effects of protein and polymer concentrations on particle morphology and protein release, using scanning electron microscopy (SEM) and fluorometry techniques. The optimum formulation was selected based on higher protein release, and smaller particle size. The optimum formulation was then tested in vitro for cell biocompatibility and protein internalization, and in vivo for cellular toxicity following sub-retinal injections into rat eyes. The results suggest that PEG–PLA microparticles can deliver proteins in cell culture allowing protein internalization in as little as 1 h. In vivo, protein was shown to localize within the photoreceptor layer of the retina, and persist for at least 9 weeks with no observed toxicity.
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| 2. |
- Wassmer, Sarah, et al.
(författare)
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Chitosan microparticles for delivery of proteins to the retina
- 2013
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Ingår i: Acta Biomaterialia. - : Elsevier. - 1742-7061 .- 1878-7568. ; 9:8, s. 7855-7864
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Tidskriftsartikel (refereegranskat)abstract
- Chitosan microparticles (CMPs) have previously been developed for topical applications to the eye, but their safety and efficacy in delivering proteins to the retina have not been adequately evaluated. This study examines the release kinetics of CMPs in vitro, and assesses their biocompatibility and cytotoxicity on retinal cells in vitro and in vivo. Two proteins were used in the encapsulation and release studies: BSA (bovine serum albumin) and tat-EGFP (enhanced green fluorescent protein fused to the transactivator of transcription peptide). Not surprisingly, the in vitro release kinetics were dependent on the protein encapsulated, with BSA showing higher release than tat-EGFP. CMPs containing encapsulated tat-EGFP were tested for cellular toxicity in photoreceptor-derived 661W cells. They showed no signs of in vitro cell toxicity at a low concentration (up to 1 mg ml 1), but at a higher concentration of 10 mg ml1 they were associated with cytotoxic effects. In vivo, CMPs injected into the subretinal space were found beneath the photoreceptor layer of the retina, and persisted for at least 8 weeks. Similar to the in vitro studies, the lower concentration of CMPs was generally well tolerated, but the higher concentration resulted in cytotoxic effects and in reduced retinal function, as assessed by electroretinogram amplitudes. Overall, this study suggests that CMPs are effective long-term delivery agents to the retina, but the concentration of chitosan may affect cytotoxicity.
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