H2S Activated Drug Release from Protein Cages

H2S Sensors: Synthesis, Optical Properties, and Selected Biomedical Applications under Visible and NIR Light

Hydrogen sulfide (H₂S) is an essential signaling gas within the cell, and its endogenous levels are correlated with various health diseases such as Alzheimer's disease, diabetes, Down's syndrome, and cardiovascular disease. Because it plays such diverse biological functions, being able to detect H₂S quickly and accurately in vivo is an area of heightened scientific interest. Using probes that fluoresce in the near-infrared (NIR) region is an effective and convenient method of detecting H₂S. This approach allows for compounds of high sensitivity and selectivity to be developed while minimizing cytotoxicity. Herein, we report a review on the synthesis, mechanisms, optical properties, and selected biomedical applications of H₂S sensors.

Hydrogen Sulfide: An Emerging Precision Strategy for Gas Therapy

Advances in nanotechnology have enabled the rapid development of stimuli-responsive therapeutic nanomaterials for precision gas therapy. Hydrogen sulfide (H₂ S) is a significant gaseous signaling molecule with intrinsic biochemical properties, which exerts its various physiological effects under both normal and pathological conditions. Various nanomaterials with H₂ S-responsive properties, as new-generation therapeutic agents, are explored to guide therapeutic behaviors in biological milieu. The cross disciplinary of H₂ S is an emerging scientific hotspot that studies the chemical properties, biological mechanisms, and therapeutic effects of H₂ S. This review summarizes the state-of-art research on H₂ S-related nanomedicines. In particular, recent advances in H₂ S therapeutics for cancer, such as H₂ S-mediated gas therapy and H₂ S-related synergistic therapies (combined with chemotherapy, photodynamic therapy, photothermal therapy, and chemodynamic therapy) are highlighted. Versatile imaging techniques for real-time monitoring H₂ S during biological diagnosis are reviewed. Finally, the biosafety issues, current challenges, and potential possibilities in the evolution of H₂ S-based therapy that facilitate clinical translation to patients are discussed.

Hydrogen Sulfide-Responsive Bicontinuous Nanospheres

Block copolymers (BCPs) that can self-assemble into particles and be triggered by disease-specific molecules such as hydrogen sulfide (H₂S) have the potential to impact on drug delivery, decreasing off-target toxicities while increasing drug efficacy. However, the incorporation of H₂S-responsive aryl azides into BCPs for self-assembly has been limited by heat, light, and radical sensitivities. In this study, a robust activator regenerated by the electron-transfer atom-transfer radical polymerization reaction was used to synthesize aryl-azide-containing BCPs under ambient conditions. Conditions controlling self-assembly of the BCPs into 150-200 nm particles and the physicochemical properties of the particles were investigated. The use of nanoprecipitation with tetrahydrofuran to promote self-assembly of the BCPs resulted in vesicle structures, while dimethylformamide or dimethylsulfoxide resulted in polymeric bicontinuous nanospheres (BCNs). Triggering of the BCPs and particles (vesicles or BCNs) via exposure to H₂S revealed that unsubstituted aryl azides were readily reduced (by HS^-), resulting in particle disruption or cross-linking. The relative polar nature of the particle bilayers containing unsubstituted aryl azides and the open structure of the BCNs did however limit encapsulation of small hydrophilic and hydrophobic payloads. Incorporation of a benzylamide substituent onto the aryl azide group increased the hydrophobicity of the particles and encapsulation of hydrophilic cargo but reduced sensitivity to H₂S, likely due to the reduced penetration of HS^- into the bilayer.

Recent progress of redox-responsive polymeric nanomaterials for controlled release

This perspective focuses on the development of redox-responsive polymeric nanomaterials for controlled payload release within the last four years.

Temozolomide-Doxorubicin Conjugate as a Double Intercalating Agent and Delivery by Apoferritin for Glioblastoma Chemotherapy

We designed a conjugated compound by coupling temozolomide (TMZ) with doxorubicin (DOX) via an acylhydrazone linkage as a potential prodrug used for glioblastoma multiforme (GBM) treatment. Viscosity and spectroscopic studies revealed that the drug conjugate could act as a nonclassical double intercalating agent. Although free TMZ is an inefficient DNA binder in comparison to DOX, the TMZ moiety interacted with DNA as an induced intercalator, arising from the synergistic effect of DOX moiety that mediated conformational changes of the DNA helix. Two binding modes were proposed to interpret the double intercalating effect of the drug conjugate on intra- and inter-DNA interactions that could cause DNA cross-linking and fibril aggregates. We also developed a delivery nanoplatform with a loading efficiency of 83% using copper-bound apoferritin as a nanocarrier. In sharp contrast to the short half-life of free TMZ, the nanocomposite was stable under physiological conditions without detectable drug decomposition after a 2 week storage, and drug release was activatable in the presence of glutathione at millimolar levels. The antitumor effect of the drug conjugate and nanocomposite against GBM cells was reported to demonstrate the potential therapeutic applications of double intercalating materials.

Protein-based nanoplatforms for tumor imaging and therapy

Cancer is one of the leading causes of death all over the world. The development of nanoplatform provides a promising strategy for the diagnosis and treatment of cancer. As the foundation of the nanoplatform, the composition of nanocarrier decides the basic properties. Protein exists in all kinds of life and participates in any life activities, having great potentials to serve as a nanocarrier because of its excellent biocompatibility, abundance of functional groups, and inherent biological activity. As a result, protein-based nanoplatforms have evoked extensive interests for tumor imaging and therapy. This review presents the latest progresses on the advancement of protein-based nanoplatforms, introducing the most common protein nanocarriers (such as human/bovine serum albumin, ferritin, human transferrin) thoroughly including their physiochemical properties and specific applications. Also, other kinds of protein are briefly involved. Finally, the prospects and challenges of the development of protein-based nanoplatforms are summarized. This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Precise engineering of apoferritin through site-specific host–guest binding

An efficient non-covalent method for precise engineering of the apoferritin surface at twelve two-fold channels is established using a PEGylated porphyrin.

Recent progress in H2S activated diagnosis and treatment agents

This review summarizes the recent advances in H₂S detection probes and H₂S-activated tumor treatment agents.