Stimuli-Responsive Drug Delivery Systems Using Polymeric and Liposomal Approaches

Stimuli-responsive drug delivery systems harness changes in the local or externally applied environment to trigger the release of therapeutic agents at a desired site and time. Polymeric carriers, including block copolymer micelles, nanogels and polymersomes, can be engineered to undergo phase transitions or disassemble in response to pH shifts, redox gradients, enzymes or gasotransmitters present in diseased tissue. Liposomal vehicles, composed of lipid bilayers, offer a biocompatible scaffold that may be modified with responsive moieties—such as photosensitisers or metallic nanoparticles—to achieve light-, temperature- or irradiation-triggered permeability. Such ‘smart’ constructs improve drug bioavailability, reduce off-target effects and allow combination regimens (for example photodynamic and chemotherapeutic approaches). Advances in polymer–lipid hybrid vesicles further integrate the robustness of synthetic polymers with the inherent biocompatibility of liposomes, enabling multi-modal triggers and precise control over cargo release kinetics. These systems hold promise for applications in oncology, infection control and regenerative medicine by providing on-demand, site-specific therapeutics while minimising systemic toxicity.

Research from Nature Portfolio

One seminal study demonstrated liposomes embedded with gold nanoparticles and a photosensitiser to achieve X-ray-triggered singlet oxygen generation and membrane destabilisation. Upon megavoltage irradiation, the photosensitiser produces reactive oxygen species that transiently compromise the bilayer, releasing encapsulated chemotherapy agents and gene-silencing constructs in deep tissues. This approach overcame the penetration limits of conventional light-responsive liposomes and exhibited synergistic enhancement of radiotherapy and chemotherapy in vivo, pointing to new avenues for radiotherapy-guided drug release and combinatorial treatment strategies.

Stimuli-Responsive Drug Delivery Systems Using Polymeric and Liposomal Approaches publication trend

The graph below shows the total number of articles in stimuli-responsive drug delivery systems using polymeric and liposomal approaches across all publications each year (not limited to Nature Index journals).

Technical terms

Stimuli-responsive material: A polymer or assembly that undergoes a physicochemical change in response to a specific trigger.

Liposome: A vesicular carrier composed of one or more phospholipid bilayers enclosing an aqueous core.

Block copolymer: A macromolecule made of two or more polymer segments covalently linked, capable of self-assembly into defined nanostructures.

Photosensitiser: A molecule that generates reactive species (for example singlet oxygen) upon light irradiation, used to induce membrane permeabilisation.

Singlet oxygen: A highly reactive form of molecular oxygen generated by energy transfer from an excited photosensitiser.

Bioconjugation: The chemical coupling of biological ligands (antibodies, peptides) or polymers to a carrier surface to improve targeting or stability.

References

1. Controlled gene and drug release from a liposomal delivery platform triggered by X-ray radiation. Nature Communications (2018).
2. Recent Progress in Bioconjugation Strategies for Liposome-Mediated Drug Delivery. Molecules (2020).
3. A Concise Review of Gold Nanoparticles-Based Photo-Responsive Liposomes for Controlled Drug Delivery. Nano-Micro Letters (2017).
4. A triblock terpolymer vs. blends of diblock copolymers for nanocapsules addressed by three independent stimuli. Polymer Chemistry (2016).
5. H 2 S gasotransmitter-responsive polymer vesicles. Chemical Science (2016).