Fabrication of PεCL-AuNP-BSA core-shell-corona nanoparticles for flexible spatiotemporal drug delivery and SERS detection

Bonding states of gold/silver plasmonic nanostructures and sulfur-containing active biological ingredients in biomedical applications: a review

As one of the most instrumental components in the architecture of advanced nanomedicines, plasmonic nanostructures (mainly gold and silver nanomaterials) have been paid a lot of attention. This type of nanomaterial can absorb light photons with a specific wavelength and generate heat or excited electrons through surface resonance, which is a unique physical property. In innovative biomaterials, a significant number of theranostic (therapeutic and diagnostic) materials are produced through the conjugation of thiol-containing ingredients with gold and silver nanoparticles (Au and Ag NPs). Hence, it is essential to investigate Au/Ag-S interfaces precisely and determine the exact bonding states in the active nanobiomaterials. This study intends to provide useful insights into the interactions between Au/Ag NPs and thiol groups that exist in the structure of biomaterials. In this regard, the modeling of Au/Ag-S bonding in active biological ingredients is precisely reviewed. Then, the physiological stability of Au/Ag-based plasmonic nanobioconjugates in real physiological environments (pharmacokinetics) is discussed. Recent experimental validation and achievements of plasmonic theranostics and radiolabelled nanomaterials based on Au/Ag-S conjugation are also profoundly reviewed. This study will also help researchers working on biosensors in which plasmonic devices deal with the thiol-containing biomaterials (e.g., antibodies) inside blood serum and living cells.

Polymer-Protein Nanovaccine Synthesized via Reactive Self-Assembly with Potential Application in Cancer Immunotherapy: Physicochemical and Biological Characterization In Vitro and In Vivo

Nanovaccines composed of polymeric nanocarriers and protein-based antigens have attracted much attention in recent years because of their enormous potential in the prevention and treatment of diseases such as viral infections and cancer. While surface-conjugated protein antigens are known to be more immunoactive than encapsulated antigens, current surface conjugation methods often result in low and insufficient protein loading. Herein, reactive self-assembly is used to prepare nanovaccine from poly(ε-caprolactone) (PCL) and ovalbumin (OVA)-a model antigen. A rapid thiol-disulfide exchange reaction between PCL with pendant pyridyl disulfide groups and thiolated OVA results in the formation of nanoparticles with narrow size distribution. High OVA loading (≈70-80 wt%) is achieved, and the native secondary structure of OVA is preserved. Compared to free OVA, the nanovaccine is much superior in enhancing antigen uptake by bone marrow-derived dendritic cells (BMDCs), promoting BMDC maturation and antigen presentation via the MHC I pathway, persisting at the injection site and draining lymph nodes, activating both Th1 and Th2 T cell immunity, and ultimately, resisting tumor challenge in mice. This is the first demonstration of reactive self-assembly for the construction of a polymer-protein nanovaccine with clear potential in advancing cancer immunotherapy.

Intracellular delivery and photothermal therapeutic effects of polyhistidine peptide-modified gold nanoparticles

Gold nanoparticles (AuNPs) are widely used as an agent in photothermal therapy (PTT) against various cancers. However, a drug delivery system (DDS) is required for effective PTT using AuNPs as AuNPs accumulate passively in tumors. In the present study, we used polyhistidine peptide, a novel cell-penetrating peptide, which is efficiently internalized into tumor cells, as a DDS carrier for PTT using AuNPs. Polyhistidine peptide-modified AuNPs are efficiently internalized into RERF-LC-AI human lung squamous cancer cells and localized to the intracellular lysosome, which is based on the nature of the polyhistidine peptide. Furthermore, the polyhistidine peptide-modified AuNPs inhibited proliferation of RERF-LC-AI cells in a polyhistidine peptide modification-dependent manner under 660 nm laser irradiation. Quantitative real-time PCR showed increased expression levels of an apoptosis-related gene (bax) and heat stress-related gene (hsp70) in RERF-LC-AI cells treated with polyhistidine peptide-modified AuNPs and laser. Our findings highlight the efficacy of AuNPs modified with H16 peptide in PTT.

Chemical Enhancement Effect of Icotinib-Au Complex Studied by Combined Density Functional Theory and Surface-Enhanced Raman Scattering

Icotinib is an epidermal growth factor receptor tyrosine kinase inhibitor used in the treatment of non-small cell lung cancer. The charge transfer effect between gold nanoparticles (AuNPs) and icotinib molecules can be used as a model to study the adsorption mechanism between molecules and metal. The adsorption of icotinib on the AuNP surface was confirmed by UV-vis and transmission electron microscopy (TEM) experiments. To explain the nature of chemisorption between icotinib and AuNPs from a theoretical perspective, the molecular correlation properties of the complex model of icotinib-Au₆ were studied by the density functional theory method. By studying the molecular electrostatic potential of an icotinib molecule, four potential binding sites of the icotinib molecule were predicted. The calculation results of binding energy showed that the complex formed by chemisorption of icotinib through acetylene group and Au₆ was the most stable one. The molecular frontier orbitals of icotinib and icotinib-Au₆ confirmed that the charge transfer effect occurred on the acetylene group, benzene ring, and quinazoline ring of the icotinib molecule. The Herzberg-Teller surface selection rule was used to explain selective enhancement in the theoretically calculated Raman spectra. By comparing the spectra of theory and experiment, the cause of spectral peak shift and broadening that appeared in the surface-enhanced Raman scattering spectrum compared with the normal Raman spectrum was explained as well. This work would contribute to the development and application of the icotinib-Au drug carrier system.

Advanced and Innovative Nano-Systems for Anticancer Targeted Drug Delivery

The encapsulation of therapeutic agents into nano-based drug delivery system for cancer treatment has received considerable attention in recent years. Advancements in nanotechnology provide an opportunity for efficient delivery of anticancer drugs. The unique properties of nanoparticles not only allow cancer-specific drug delivery by inherent passive targeting phenomena and adopting active targeting strategies, but also improve the pharmacokinetics and bioavailability of the loaded drugs, leading to enhanced therapeutic efficacy and safety compared to conventional treatment modalities. Small molecule drugs are the most widely used anticancer agents at present, while biological macromolecules, such as therapeutic antibodies, peptides and genes, have gained increasing attention. Therefore, this review focuses on the recent achievements of novel nano-encapsulation in targeted drug delivery. A comprehensive introduction of intelligent delivery strategies based on various nanocarriers to encapsulate small molecule chemotherapeutic drugs and biological macromolecule drugs in cancer treatment will also be highlighted.