Sequential Delivery and Cascade Targeting of Peptide Therapeutics for Triplexed Synergistic Therapy with Real-Time Monitoring Shuttled by Magnetic Gold Nanostars

Multifunctional Plasmon-Tunable Au Nanostars and Their Applications in Highly Efficient Photothermal Inactivation and Ultra-Sensitive SERS Detection

The development and application in different fields of multifunctional plasmonic nanoparticles (NPs) have always been research hotspots. Herein, multi-tip Au nanostars (NSs) with an anisotropic structure were fabricated for the photothermal therapy (PTT) of bacteria and surface-enhanced Raman scattering (SERS) detection of pollutants. The size and localized surface plasmon resonance (LSPR) characteristics of Au NSs were adjusted by varying Au seed additions. In addition, photothermal conversion performance of Au NSs with various Au seed additions was evaluated. Photothermal conversion efficiency of Au NSs with optimal Au seed additions (50 μL) was as high as 28.75% under 808 nm laser irradiation, and the heat generated was sufficient to kill Staphylococcus aureus (S. aureus). Importantly, Au NSs also exhibited excellent SERS activity for the 4-mercaptobenzoic acid (4-MBA) probe molecule, and the local electromagnetic field distribution of Au NSs was explored through finite-difference time-domain (FDTD) simulation. As verified by experiments, Au NSs' SERS substrate could achieve a highly sensitive detection of a low concentration of potentially toxic pollutants such as methylene blue (MB) and bilirubin (BR). This work demonstrates a promising multifunctional nanoplatform with great potential for efficient photothermal inactivation and ultra-sensitive SERS detection.

Shape-dependent gold nanoparticle interactions with a model cell membrane

Customizable gold nanoparticle platforms are motivating innovations in drug discovery with massive therapeutic potential due to their biocompatibility, stability, and imaging capabilities. Further development requires the understanding of how discrete differences in shape, charge, or surface chemistry affect the drug delivery process of the nanoparticle. The nanoparticle shape can have a significant impact on nanoparticle function as this can, for example, drastically change the surface area available for modifications, such as surface ligand density. In order to investigate the effects of nanoparticle shape on the structure of cell membranes, we directly probed nanoparticle-lipid interactions with an interface sensitive technique termed sum frequency generation (SFG) vibrational spectroscopy. Both gold nanostars and gold nanospheres with positively charged ligands were allowed to interact with a model cell membrane and changes in the membrane structure were directly observed by specific SFG vibrational modes related to molecular bonds within the lipids. The SFG results demonstrate that the +Au nanostars both penetrated and impacted the ordering of the lipids that made up the membrane, while very little structural changes to the model membrane were observed by SFG for the +Au nanospheres interacting with the model membrane. This suggests that the +Au nanostars, compared to the +Au nanospheres, are more disruptive to a cell membrane. Our findings indicate the importance of shape in nanomaterial design and provide strong evidence that shape does play a role in defining nanomaterial-biological interactions.

Glutathione-triggered nanoplatform for chemodynamic/metal-ion therapy

The integration of metal-ion therapy and hydroxyl radical (˙OH)-mediated chemodynamic therapy (CDT) holds great potential for anticancer treatment with high specificity and efficiency. Herein, Ag nanoparticles (Ag NPs) were enveloped with Cu²⁺-based metal-organic frameworks (MOFs) and further decorated with hyaluronic acid (HA) to construct a glutathione (GSH)-activated nanoplatform (Ag@HKU-HA) for specific chemodynamic/metal-ion therapy. The obtained nanoplatform could avoid the premature leakage of Ag in circulation, but realize the release of Ag at the tumor site owing to the degradation of external MOFs triggered by Cu²⁺-reduced glutathione. The generated Cu⁺ could catalyze endogenous H₂O₂ to the highly toxic ˙OH by a Fenton-like reaction. Meanwhile, Ag NPs were oxidized to toxic Ag ions in the tumor environment. As expect, the effect of CDT combined with metal-ion therapy exhibited an excellent inhibition of tumor cells growth. Therefore, this nanoplatform may provide a promising strategy for on-demand site-specific cancer combination treatment.

In situ growth gold nanoparticles in three-dimensional sugarcane membrane for flow catalytical and antibacterial application

In this work, we decorated gold nanoparticles (Au NPs) in the porous, three-dimensional sugarcane membrane for the flow catalytical and antibacterial application. Due to the uniformly distributed Au NPs in sugarcane channels and the porous structure of sugarcane, the interaction between contaminant and catalysis was enhanced as water flowing through the Au NPs/sugarcane membrane. The Au NPs/sugarcane membrane exhibited superior catalytical efficiency for removing methylene blue (MB) with a turn over frequency of 0.27 mol_MB·mol_Au^-1·min^-1 and the water treatment rate reached up to 1.15×10⁵ L/m² h with >98.3 % MB removal efficiency. The Au NPs/sugarcane membrane also exhibited superior bacterial removal efficiency as E. coli suspension flowing through it, due to the superimposition effects of physical barrier in sugarcane and the antibacterial property of Au NPs. The tremendous catalytical and antibacterial performance of Au NPs/sugarcane membrane provides a promising potential for the rational design of flow catalytical membrane reactor to purify the microbial contaminated water.

Dual catalytic cascaded nanoplatform for photo/chemodynamic/starvation synergistic therapy

In this study, manganese dioxide (MnO₂) was attached to prussian blue (PB) by a one-pot method to prepare PBMO. Then, the GOD was loaded onto PBMO through the electrostatic interaction of hyaluronic acid (HA) to form tumor-targeted nanoplatform (PBMO-GH). Hydrogen peroxide (H₂O₂) and gluconic acid were produced through the GOD-catalyzed enzymatic reaction. Meanwhile, PB could not only catalyze H₂O₂ for oxygen generation to further promote glucose consumption but also possess the property of photothermal conversion. As a result, glucose was continuously consumed to achieve the starvation therapy (ST), and the photothermal therapy (PTT) could be realized under near-infrared (NIR) light. Besides, the Mn²⁺ generated by the reaction of MnO₂ with glutathione (GSH) could exert Fenton-like reaction to produce highly toxic hydroxyl radicals (·OH) from H₂O₂, which thereby realized self-reinforcing chemodynamic therapy (CDT). In vitro and in vivo experiments demonstrated that PBMO-GH could effectively inhibit the growth of tumor cells via ST/CDT/PTT synergistic effect. Therefore, the as-prepared nanoplatform for multi-modal therapy will provide a promising paradigm for overcoming cancer.

Nanoplatform-based cascade engineering for cancer therapy

Various therapeutic techniques have been studied for treating cancer precisely and effectively, such as targeted drug delivery, phototherapy, tumor-specific catalytic therapy, and synergistic therapy, which, however, evoke numerous challenges due to the inherent limitations of these therapeutic modalities and intricate biological circumstances as well. With the remarkable advances of nanotechnology, nanoplatform-based cascade engineering, as an efficient and booming strategy, has been tactfully introduced to optimize these cancer therapies. Based on the designed nanoplatforms, pre-supposed cascade processes could be triggered under specific conditions to generate/deliver more therapeutic species or produce stronger tumoricidal effects inside tumors, aiming to achieve cancer therapy with increased anti-tumor efficacy and diminished side effects. In this review, the recent advances in nanoplatform-based cascade engineering for cancer therapy are summarized and discussed, with an emphasis on the design of smart nanoplatforms with unique structures, compositions and properties, and the implementation of specific cascade processes by means of endogenous tumor microenvironment (TME) resources and/or exogenous energy inputs. This fascinating strategy presents unprecedented potential in the enhancement of cancer therapies, and offers better controllability, specificity and effectiveness of therapeutic functions compared to the corresponding single components/functions. In the end, challenges and prospects of such a burgeoning strategy in the field of cancer therapy will be discussed, hopefully to facilitate its further development to meet the personalized treatment demands.

Label-Free SERS Strategy for In Situ Monitoring and Real-Time Imaging of Aβ Aggregation Process in Live Neurons and Brain Tissues

The aggregation of Aβ has been reported to closely correlate with Alzheimer's disease (AD). However, clear monitoring of the entire aggregation process of Aβ from monomer to fibril has been scarcely reported until now. Herein, we developed a label-free ratiometric surface enhanced Raman spectroscopic (SERS) platform for real-time monitoring of the entire process of Aβ aggregation in neurons and brain tissues. Different gold nanoparticles, generated in situ with Aβ monomer and fibril as templates separately, were served as effective SERS substrates to achieve a high sensitivity with a limit of detection (LOD) down to 70 ± 4 pM and 3.0 ± 0.5 pM for Aβ₄₀ monomer and fibrils, respectively. Besides, the introduction of ratiometric determination of Aβ monomer and fibril (I₁₂₄₄/I₁₂₆₈) realized real-time monitoring of the entire aggregation process of Aβ monomer with high accuracy and selectivity against other proteins and amino acids. The significant analytical performance of the developed platform, together with good biocompatibility, long-term stability, and remarkable spatial resolution, enabled the present SERS platform imaging and real-time monitoring and imaging of Aβ aggregation influenced by different metal ions (Cu²⁺, Zn²⁺, and Fe³⁺) in neurons and brain tissues at the single cell level. Our results suggested that Cu²⁺ and Zn²⁺ ion of low concentration (10 μM) promoted fibril formation, while Fe³⁺ and Zn²⁺ of high concentration (100 μM) showed inhibition of fibrosis.