Radiation Crosslinked Smart Peptide Nanoparticles: A New Platform for Tumor Imaging

Hydroxyl radical scavenging and chemical repair capabilities of positively charged peptides (PCPs): a pulse radiolysis study

Pulse radiolysis was employed to investigate fundamental radiation chemical reactions, which are essential in the radiation protection of DNA. Two positively charged peptides (PCPs), histidine-tyrosine-histidine (His-Tyr-His) and lysine-tyrosine-lysine (Lys-Tyr-Lys), as well as the amino acids that constitute them, were involved. The reaction rate constants for tyrosine (Tyr), histidine (His), lysine (Lys), His-Tyr-His, and Lys-Tyr-Lys with OH radicals (•OH) were (1.6 ± 0.3) × 1010, (9.0 ± 0.9) × 109, (1.4 ± 0.3) × 109, (1.8 ± 0.1) × 1010, and (1.0 ± 0.1) × 1010 M-1s-1, respectively, indicating that formation of peptide bond can affect the reaction of amino acids with •OH. Observed transient absorption spectra indicated a shielding effect of the His or Lys residues at both ends of the PCPs on the centrally located Tyr. The measurement of chemical repair capabilities using deoxyguanosine monophosphate (dGMP) as a model for DNA demonstrated that the reaction rate constants of Tyr, His-Tyr-His, and Lys-Tyr-Lys with dGMP radicals were (2.2 ± 0.5) × 108, (2.3 ± 0.1) × 108, and (3.3 ± 0.4) × 108 M-1s-1, respectively, implying that the presence of a positive charge may enhance the chemical repair process.

Synthesis of Small Peptide Nanogels Using Radiation Crosslinking as a Platform for Nano-Imaging Agents for Pancreatic Cancer Diagnosis

Nanoparticle-based drug delivery systems (DDS) have been developed as effective diagnostic and low-dose imaging agents. Nano-imaging agents with particles greater than 100 nm are difficult to accumulate in pancreatic cancer cells, making high-intensity imaging of pancreatic cancer challenging. Peptides composed of histidine and glycine were designed and synthesized. Additionally, aqueous peptide solutions were irradiated with γ-rays to produce peptide nanogels with an average size of 25-53 nm. The mechanisms underlying radiation-mediated peptide crosslinking were investigated by simulating peptide particle formation based on rate constants. The rate constants for reactions between peptides and reactive species produced by water radiolysis were measured using pulse radiolysis. HGGGHGGGH (H9, H-histidine; G-glycine) particles exhibited a smaller size, as well as high formation yield, stability, and biodegradability. These particles were labeled with fluorescent dye to change their negative surface potential and enhance their accumulation in pancreatic cancer cells. Fluorescent-labeled H9 particles accumulated in PANC1 human pancreatic cancer cells, demonstrating that these particles are effective nano-imaging agents for intractable cancers.

Radiation-Assisted Synthesis of Polymer-Based Nanomaterials

Radiation technology has long been proven as a simple, rapid, green and sustainable technology with macroscale applications in healthcare, industry and environment. Its merits, however, have not been fully utilized in today’s ever growing nanotechnology. Ionizing radiation has beneficial effects for the synthesis and modification of structure and properties of nanomaterials. This paper intends to update the application of ionizing radiation in the development of various nanomaterials under the categories: (i) carbon-based nanomaterials, (ii) metal-based nanomaterials, (iii) polymer-based nanomaterials, (iv) polymer nanocomposites and (v) nano-scale grafting for advanced membrane applications.