Synthesis of Single-Walled Carbon Nanotubes Coated with Thiol-Reactive Gel via Emulsion Polymerization

Temperature response of defect photoluminescence in locally functionalized single-walled carbon nanotubes

In vivo temperature monitoring has garnered significant attention for studying biological processes such as cellular differentiation and enzymatic activity. However, current nanoscale thermometers utilizing photoluminescence (PL) in the visible to first near-infrared (NIR-I) region based on organic dyes, quantum dots, and lanthanide-doped nanoparticles face challenges in terms of tissue penetration and sensitivity. In this study, we investigated the temperature dependence of PL (1140 nm) and PL (1260 nm) of locally functionalized single-walled carbon nanotubes (lf-SWCNTs) that emit in the second near-infrared region (NIR-II). The effects of interfacial dielectric environments (hydrophobic surfactant dispersion vs. hydrophilic gel coating), defect density, and nanotube length on the temperature responsiveness were systematically examined. The results demonstrated that PL was more sensitive to temperature changes than PL and lf sites having a lower dielectric environment further enhanced temperature responsiveness. Additionally, longer lf-SWCNTs exhibited greater temperature responsiveness than the shorter ones. These findings provide valuable insights into optimizing gel-coated lf-SWCNTs to achieve higher temperature responsiveness and develop biocompatible temperature sensors capable of monitoring deep tissues within complex biological environments.

Polymer-coated carbon nanotube hybrids with functional peptides for gene delivery into plant mitochondria

The delivery of genetic material into plants has been historically challenging due to the cell wall barrier, which blocks the passage of many biomolecules. Carbon nanotube-based delivery has emerged as a promising solution to this problem and has been shown to effectively deliver DNA and RNA into intact plants. Mitochondria are important targets due to their influence on agronomic traits, but delivery into this organelle has been limited to low efficiencies, restricting their potential in genetic engineering. This work describes the use of a carbon nanotube-polymer hybrid modified with functional peptides to deliver DNA into intact plant mitochondria with almost 30 times higher efficiency than existing methods. Genetic integration of a folate pathway gene in the mitochondria displays enhanced plant growth rates, suggesting its applications in metabolic engineering and the establishment of stable transformation in mitochondrial genomes. Furthermore, the flexibility of the polymer layer will also allow for the conjugation of other peptides and cargo targeting other organelles for broad applications in plant bioengineering.

The delivery of genetic material into plants is challenging due to the cell wall barrier. Here, the authors hybridize polymer-coated carbon nanotubes with functional peptides to deliver plasmid DNA cargo into intact plant mitochondria for transient expression and homologous recombination at high efficiency.

Diverse 3-Methylthio-4-Substituted Maleimides through a Novel Rearrangement Reaction: Synthesis and Selective Cell Imaging

A transition metal-free protocol for the preparation of fluorescent and non-fluoresent 3-methylthio-4-arylmaleimides in a single step through a new rearrangement from thiazolidine-2,4-diones is described. By employing the optimized reaction conditions, a broad scope of derivatives was prepared in ≤97% yield. The reaction tolerated several substituted aryl groups, including the challenging preparation of pyridyl-containing derivatives. A series of control experiments strongly suggested that the new rearrangement involves a key isocyanate intermediate and a further reaction with in situ-generated methylthiomethyl acetate. The photophysical properties of some of the synthesized derivatives as well as their use in live cell imaging were also investigated, revealing that some of the substituted maleimides are capable of selectively staining different regions of the cells.

Antibody-Conjugated Gel-Coated Single-Walled Carbon Nanotubes as Photothermal Agents

Photothermal therapy (PTT) using near-infrared (NIR) light is an attractive treatment modality for cancer, in which photothermal agents absorb energy from photons and convert it into thermal energy to lead to cancer cell death. Among the various organic and inorganic materials, single-walled carbon nanotubes (SWCNTs) are promising candidates for NIR photothermal agents due to their strong absorption in this region as well as their high photothermal conversion efficiency. In the development of the SWCNT-based PTT materials, modifications of SWCNTs to offer a stable dispersion for biocompatibility as well as to target the tumor of choice while maintaining their NIR absorption have been required. While modification of SWCNTs through noncovalent methods can be achieved, these modifications can be easily reversed in the body. Contrarily, modifications through covalent attachments, while more desirable, may compromise the NIR absorption characteristics of the SWCNTs. Previously, we reported the development of a synthetic strategy to coat SWCNTs with a cross-linked polymer (i.e., a gel) through a process called CNT Micelle Polymerization and successfully introduced maleimide groups that allowed for postmodification through the ene-thiol reaction without deteriorating the NIR absorption. In this report, we postmodify thiol-containing antibodies (anti-TRP-1, a melanoma specific protein) using maleimide chemistry and find that the SWCNTs conjugated with anti-TRP-1 maintain the characteristic NIR absorption as SWCNTs with dispersion stability. It is estimated that 50 maleimide groups are incorporated in one SWCNT (ca. 280 nm long) and they are modified with 32 TRP-1 fragments. Finally, we successfully use these targeted SWCNTs for the PTT of the melanoma cell line using NIR light (1064 nm; 2 W, 5 min). Our method can be extended to a vast array of specific antibodies as well as other targeting agents.

Stereoisomeric furan/maleimide adducts as latent monomers for one-shot sequence-controlled polymerization

Two stereoisomeric latent monomers were used for one-shot sequence-controlled polymerization to create diverse sequence structures.

Brighter near-IR emission of single-walled carbon nanotubes modified with a cross-linked polymer coating

Photoluminescence (PL) in the near-infrared (NIR) region is an attractive feature of single-walled carbon nanotubes (SWNTs). In this study, we investigated the effect of the chemical structure of the cross-linked polymer coating of polymer-coated SWNTs on the NIR PL emission intensity. We found that brighter NIR emission can be achieved using a more hydrophobic polymer coating.

In Situ Fabrication of Intelligent Photothermal Indocyanine Green-Alginate Hydrogel for Localized Tumor Ablation

Simplifying synthesis and administration process, improving photothermal agents' accumulation in tumors, and ensuring excellent biocompatibility and biodegradability are keys to promoting the clinical application of photothermal therapy. However, current photothermal agents have great difficulties in meeting the requirements of clinic drugs from synthesis to administration. Herein, we reported the in situ formation of a Ca²⁺/Mg²⁺ stimuli-responsive ICG-alginate hydrogel in vivo for localized tumor photothermal therapy. An ICG-alginate hydrogel can form by the simple introduction of Ca²⁺/Mg²⁺ into ICG-alginate solution in vitro, and the widely distributed divalent cations in organization in vivo enabled the in situ fabrication of the ICG-alginate hydrogel without the leakage of any agents by simple injection of ICG-alginate solution into the body of mice. The as-prepared ICG-alginate hydrogel not only owns good photothermal therapy efficacy and excellent biocompatibility but also exhibits strong ICG fixation ability, greatly benefiting the high photothermal agents' accumulation and minimizing the potential side effects induced by the diffusion of ICG to surrounding tissues. The in situ-fabricated ICG-alginate hydrogel was applied successfully in highly efficient PTT in vivo without obvious side effects. Besides, the precursor of the hydrogel, ICG and alginate, can be stored in a stable solid form, and only simple mixing and noninvasive injection are needed to achieve PTT in vivo. The proposed in situ gelation strategy using biocompatible components lays down a simple and mild way for the fabrication of high-performance PTT agents with the superiors in the aspects of synthesis, storage, transportation, and clinic administration.