Intracellular delivery facilitates the introduction of biomolecules such as nucleic acids, proteins, peptides, and nanoparticles into living cells, there by supporting gene therapy, vaccine development, and cellular reprogramming.
But intracellular delivery presents its own set of challenges. Transporting materials into the cell through the cell membrane must be done carefully without damaging the cell membrane or causing cell death. Biomolecules such as nucleic acids, proteins, and bacteria also have to be carefully transported into the cell without being destroyed.
There are three types of ways intracellular delivery can be done:
- Viral vectors – utilises viruses to enter a cell.
- Chemical compounds – utilises carriers such as liposomes, cationic polymers, etc. to enter a cell.
- Physical approaches – uses external physical energy or forces to enter a cell.
Of all these methods, physical approaches are becoming increasingly important as a versatile approach, because viral and chemical methods have their own set of limitations.
Viral methods are problematic because the cell’s immune system may perceive their entry as a threat, triggering a defensive response that can reduce vector delivery efficiency and cause adverse side effects. Chemical methods, too, are not effective, as the cytotoxicity (causing cell damage or cell death) of chemical transfection agents can compromise cell survival.
Physical methods are versatile and efficient compared to the use of viral vectors or chemical compounds. Physical intracellular methods include electroporation, mechanoporation, and sonoporation. But these methods also have their limitations. For example, electroporation compromises cell viability (the proportion of live, and healthy cells in a population of cells). Mechanoporation requires costly and technically complex materials such as advanced nanoneedles. Therefore, an alternative is required.
Photoporation, is a technique where light–matter interaction is used to create tiny pores in the cell membrane, allowing substances to enter the cell. This method achieves precise control over biomolecule delivery through spatial and temporal resolution. This leads to high delivery efficiency and minimal cellular damage.
This technique enables targeted delivery of diverse biomolecules such as nanoparticles, macromolecules, and genetic materials to various cell types. A major advantage of this approach is that transient membrane pore formation can be precisely controlled by tuning laser parameters such as energy, wavelength, etc.
Photoporation can accommodate a variety of biomolecules, from small, to medium, to large. They can also accommodate macromolecules and bacteria for transport into the cell.
Micro-and nanostructured materials have become indispensable in photoporation, as they modulate light-matter interactions, controlling pore formation dynamics and cargo delivery (cargo delivery refers to the transport of a large number of biomolecules) efficiency.
Metallic nanostructures, such as gold nanorods, nanostars, and nanoshells, exploit localised surface plasmon resonances (LSPRs) to amplify light absorption and generate vapour nanonubbles that transiently disrupt membranes with high precision. They help deliver substances into cells with high precision and efficiency.
In this review, the authors of this paper have analysed approximately 150 photoporation-based intracellular delivery studies in detail, using Scopus, Web of Science, and Google Scholar databases as references.
This review systematically evaluates photoporation as a versatile, non-viral intracellular delivery strategy, with a central focus on how micro- and nanostructured materials enable size-specific transport of biomolecules.
A key novelty of this review was its size-centric organisational framework, which systematically classifies photoporation strategies based on bimolecular cargo size, from small molecules and nucleic acids, to ultralarge assemblies and bacteria.
This review also examines laser-induced mechanisms responsible for transient membrane permeabilisation, and highlights critical materials parameters, including composition, size, shape, etc.
Comparative evaluation of micro- and nanostructured materials across different size regimes provides a practical framework for rational materials selection and platform design.
This review provides a structured roadmap for developing safe, efficient, and size-adaptive photoporation platforms for biological research and therapeutic applications. Continued interdisciplinary collaborations across materials science, photonics, biology, and medicine, will be key to realising the full therapeutic potential of photoporation in both research and clinical settings.
The following are the authors of this paper:
- Dr. Ashwini Surendra Shinde from the Department of Engineering Design, Indian Institute of Technology (IIT) Madras, Chennai, India.
- Dr. Gayathri R. from the Department of Engineering Design, IIT Madras. Dr. Gayathri R. is also affiliated with the Department of Mechanical Engineering, IIT Madras.
- Ms. Nandhini Balasubramaniam from the Department of Engineering Design, IIT Madras.
- Dr. Athira Prasad from the Department of Engineering Design, IIT Madras.
- Ms. Donia Dominic from the Department of Engineering Design, IIT Madras.
- Dr. Moeto Nagai from the Department of Mechanical Engineering, Toyohashi University of Technology, Aichi, Japan.
- Dr. Srabani Kar from the Department of Physics, Indian Institute of Technology (IIT) Hyderabad, Kandi, India.
- Dr. Tuhin Subhra Santra from the Department of Engineering Design, IIT Madras. Dr. Tuhin Subhra Santra is also affiliated with the School of Interdisciplinary Studies, IIT Madras, Chennai, India.
Prof. Sangjin Ryu, from the Department of Mechanical Engineering at Bradley University, Peoria, United States, pointed out the importance of the authors’ work with the following comments: “This review paper provides a well-structured overview of photoporation as a laser-based method for delivering biomolecular cargos into cells. The authors successfully reframed the field by categorizing existing photoporation methods through a lens based on the cargo size. Their strategy makes the underlying challenges and solutions of the methods much more intuitive. In addition, this review paper nicely ties together the key physical mechanisms of photoporation with practical design considerations, which comes across as both technically solid and forward-looking. Overall, the paper comprehensively presents photoporation as a versatile intracellular delivery approach with real potential for targeted and scalable applications.”
Article by Akshay Anantharaman
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