In cell technologies, the question "what was delivered?" alone is not enough. No less important is where and when what has been delivered begins to work. Researchers have proposed solving this task with light: biologically active proteins were packaged into microscopic capsules, and then a laser pulse triggered their release inside neural tissue progenitor cells. The work was published on 9 October in Scientific Reports.
The capsules can be imagined as tiny parcels with a lock that opens with light. Their diameter was about 1,7 micrometre. Two proteins were packaged inside: BDNF, brain-derived neurotrophic factor, and NeuroD1, a transcription factor that helps a cell set out on the path to becoming a neuron. The cells themselves took up the polymer capsules. Then the researchers aimed a laser at a chosen area, and the contents were released precisely there, rather than throughout the entire sample.
In laboratory experiments, such local activation influenced differentiation: the progenitor cell gradually acquired the properties of a specialized cell. Now this process can be triggered in a pinpoint manner, in the desired cell and at the desired moment.
The scientists compared two irradiation regimes: one-photon and two-photon excitation. With the selected parameters, the cells survived. The two-photon option is especially convenient: the effect arises only in a tiny focus whose volume is less than a micrometre, so the exposure can be localized very precisely.
There is also a practical advantage: the capsules can be observed. According to the article's data, their fluorescent signal remained distinguishable inside the cells for two weeks, so the delivered carriers can be tracked over time. A closely related study with photoconvertible polymer capsules went further: the researchers traced individual neural cells, and the capsules remained stable inside them for up to five weeks. Photoconversion in that work also functioned under both one-photon and two-photon irradiation.
The main value of the approach is controllability. If a signal can be delivered at a chosen point and at a given moment, a tool emerges for studying the development of nerve cells: it becomes possible to see more precisely how an individual cell responds to an exposure and how its fate changes thereafter.
The idea itself is not new. In 2015, Norbert Reich's group at the University of California, Santa Barbara, showed that hollow gold nanoparticles and a near-infrared laser make it possible to control the release of a protein inside a cell both in place and in time. The results were published in the journal Molecular Pharmaceutics. Another example: BDNF packaged in nanoparticles was released under the action of an infrared laser at a wavelength of 808 nm and supported the growth and differentiation of human neuronal progenitors in culture. At the same time, infrared light proved noticeably less toxic than ultraviolet, which was tested in the same work.
Today the topic sounds especially timely: on 5 October 2026, the Nobel Prize in Physiology or Medicine was awarded to Karl Deisseroth, Peter Hegemann and Georg Nagel for discoveries related to light-controlled ion channels and optogenetics — a method of controlling the activity of nerve cells with light. Research and innovation. The origins of this story lead back to a single-celled alga, Chlamydomonas reinhardtii: Hegemann, Nagel and their colleagues studied its light-sensitive proteins — channelrhodopsins, which work as ion channels that open under the action of light. In 2005, Deisseroth and co-authors showed that introducing channelrhodopsin-2 into neurons makes it possible to trigger their electrical activity with short pulses of blue light.
Both approaches use light for precise action on cells: optogenetics controls their electrical activity, while the microcapsules under study control the release of proteins.
The study opens up the prospect of more precise control over the development of nerve cells. In experiments on cell culture, the scientists showed that light makes it possible to release proteins locally while preserving cell viability under the selected parameters. The next stage is to study the delivery of the capsules into living tissue, methods of light activation inside the body, and the long-term safety of the method. These studies will help assess its potential for future cell therapies. Already today the platform gives scientists a valuable tool: the ability to observe how an individual cell responds to a signal and how its subsequent development changes.
