A light-triggered hydrogel depot of homotypic müller membrane vesicles enables cell-selective drug delivery and neurogenic reprogramming

Reprogramming Müller glia into neurons remains challenging due to limited cell selectivity and the transient pharmacokinetics associated with intravitreal agents. We aimed to develop a Müller cell–targeted, light-addressable drug delivery platform capable of achieving sustained, localized modulation of regenerative signaling to enhance glial-to-neuron reprogramming. To this end, we engineered a photoresponsive hydrogel–membrane vesicle depot that integrates homotypic recognition with light-triggered in situ stabilization, enabling sustained and Müller cell–selective delivery of regenerative pathway modulators. Müller cell membrane–derived vesicles were preloaded with the NOTCH inhibitor DAPT and the STAT3 inhibitor SH-4-54, then embedded within a biocompatible, photocrosslinkable hydrogel to enable localized release upon 405 nm irradiation. The platform was evaluated in primary Müller cells, NMDA-injured mouse retinas, and zebrafish retinal injury models in combination with Ascl1-mediated reprogramming. Targeting efficiency, retention, regenerative outcomes, and signaling mechanisms were assessed using cellular, histological, transcriptomic, and biochemical analyses to define the molecular basis of Müller cell-mediated retinal neuron regeneration. The photoresponsive hydrogel–membrane vesicle depot enabled sustained and Müller cell-selective delivery of regenerative pathway modulators through light-triggered in situ stabilization. In primary Müller cells, the depot synergized with Ascl1 to promote cell-cycle re-entry and enhance neurogenic reprogramming. In NMDA-injured mouse retinas, the depot preferentially accumulated in Müller cells and significantly increased their proliferative response following Ascl1-AAV transduction. Comparable regenerative effects were observed in an NMDA-injured zebrafish model. Mechanistically, hydrogel-mediated delivery prolonged Ascl1-induced RAP1 activation and sustained downstream MAPK and PI3K–AKT signaling, thereby establishing a persistent pro-regenerative signaling program that promoted Müller cell proliferation and neuronal differentiation. This light-addressable, Müller cell-targeted pharmacological depot represents a versatile biomaterial-based strategy to enhance transcription factor–induced Müller cell reprogramming for retinal neuroregeneration.