Photoactivatable (alternatively, photoremovable, photoreleasable, or photocleavable) protecting groups (PPGs), also known as caged or photocaged compounds, are used to enable non-invasive spatiotemporal photochemical control over the release of species of interest. Recent years have seen the development of PPGs activatable by biologically and chemically benign visible and near-infrared (NIR) light. These long-wavelength-absorbing moieties expand the applicability of this powerful method and its accessibility to non-specialist users. This review comprehensively covers organic and transition metal-containing photoactivatable compounds (complexes) that absorb in the visible- and NIR-range to release various leaving groups and gasotransmitters (carbon monoxide, nitric oxide, and hydrogen sulfide). The text also covers visible- and NIR-light-induced photosensitized release using molecular sensitizers, quantum dots, and upconversion and second-harmonic nanoparticles, as well as release via photodynamic (photooxygenation by singlet oxygen) and photothermal effects. Release from photoactivatable polymers, micelles, vesicles, and photoswitches, along with the related emerging field of photopharmacology, is discussed at the end of the review.

Visible-to-NIR-Light Activated Release: From Small Molecules to Nanomaterials.

Engineering of smart photoactivated nanomaterials for targeted drug delivery systems (DDS) has recently attracted considerable research interest as light enables precise and accurate controlled release of drug molecules in specific diseased cells and/or tissues in a highly spatial and temporal manner. In general, the development of appropriate light-triggered DDS relies on processes of photolysis, photoisomerization, photo-cross-linking/un-cross-linking, and photoreduction, which are normally sensitive to ultraviolet (UV) or visible (Vis) light irradiation. Considering the issues of poor tissue penetration and high phototoxicity of these high-energy photons of UV/Vis light, recently nanocarriers have been developed based on light-response to low-energy photon irradiation, in particular for the light wavelengths located in the near infrared (NIR) range. NIR light-triggered drug release systems are normally achieved by using two-photon absorption and photon upconversion processes. Herein, recent advances of light-responsive nanoplatforms for controlled drug release are reviewed, covering the mechanism of light responsive small molecules and polymers, UV and Vis light responsive nanocarriers, and NIR light responsive nanocarriers. NIR-light triggered drug delivery by two-photon excitation and upconversion luminescence strategies is also included. In addition, the challenges and future perspectives for the development of light triggered DDS are highlighted.

https://espace.library.uq.edu.au/view/UQ:a062a85/UQa062a85_OA.pdf

Remote Light-Responsive Nanocarriers for Controlled Drug Delivery: Advances and Perspectives.

Polypeptides have attracted considerable attention in recent decades due to their inherent biodegradability and tunable cytocompatibility. Macromolecular design in conjunction with rational monomer composition can direct architecture, self-assembly and chemical behavior, ultimately guiding the choice of appropriate application within the biomedical field. This review focuses on the applications of polypeptides alongside the synthetic advances in the ring opening polymerization of α-amino acid N-carboxyanhydrides achieved in the past five years. Key architectures obtained through NCA ROP or in combination with other polymerization methods are reviewed, as these play an important role in the wide range of applications towards which polypeptides have been applied.

Ring opening polymerization of α-amino acids: advances in synthesis, architecture and applications of polypeptides and their hybrids.

Stimuli-responsive transdermal microneedle patches

Inflammation plays an important role in the response to danger signals arising from damage to our body and in restoring homeostasis. Dysregulated inflammatory responses occur in many diseases, including cancer, sepsis and autoimmunity. The efficacy of anti-inflammatory drugs, developed for the treatment of dysregulated inflammation, can be potentiated using biomaterials, by improving the bioavailability of drugs and by reducing side effects. In this Review, we first outline key elements and stages of the inflammatory environment and then discuss the design of biomaterials for different anti-inflammatory therapeutic strategies. Biomaterials can be engineered to scavenge danger signals, such as reactive oxygen and nitrogen species and cell-free DNA, in the early stages of inflammation. Materials can also be designed to prevent adhesive interactions of leukocytes and endothelial cells that initiate inflammatory responses. Furthermore, nanoscale platforms can deliver anti-inflammatory agents to inflammation sites. We conclude by discussing the challenges and opportunities for biomaterial innovations in addressing inflammation. 

/pdf/design-of-therapeutic-biomaterials-to-control-inflammation-1d7elo5g.pdf

Design of therapeutic biomaterials to control inflammation

Recent Advances on Reactive Oxygen Species-Responsive Delivery and Diagnosis System.

Photoresponsive Drug/Gene Delivery Systems.

Multivalency-assisted membrane-penetrating siRNA delivery sensitizes photothermal ablation via inhibition of tumor glycolysis metabolism

Light-assisted hierarchical intratumoral penetration and programmed antitumor therapy based on tumor microenvironment (TME)-amendatory and self-adaptive polymeric nanoclusters

Huan Ye

Papers

Recent Advances on Reactive Oxygen Species-Responsive Delivery and Diagnosis System.

Photoresponsive Drug/Gene Delivery Systems.

Multivalency-assisted membrane-penetrating siRNA delivery sensitizes photothermal ablation via inhibition of tumor glycolysis metabolism

Light-assisted hierarchical intratumoral penetration and programmed antitumor therapy based on tumor microenvironment (TME)-amendatory and self-adaptive polymeric nanoclusters

Pro-Peptide-Reinforced, Mucus-Penetrating Pulmonary siRNA Delivery Mitigates Cytokine Storm in Pneumonia