Based on SERS conformational studies of ginsenoside Rb1 and its metabolites before and after combined with human serum albumin

Herb-Nanoparticle Hybrid System for Improved Oral Delivery Efficiency to Alleviate Breast Cancer Lung Metastasis

Background

Metastasis is a complex process involving multiple factors and stages, in which tumor cells and the tumor microenvironment (TME) play significant roles. A combination of orally bioavailable therapeutic agents that target both tumor cells and TME is conducive to prevent or impede the progression of metastasis, especially when undetectable. However, sequentially overcoming intestinal barriers, ensuring biodistribution in tumors and metastatic tissues, and enhancing therapeutic effects required for efficient therapy remain challenging.

Methods

Inspired by the unique chemical features of natural herbs, we propose an oral herb-nanoparticle hybrid system (HNS) formed through the self-binding of Platycodon grandiflorum-Curcuma zedoaria (HG), a herb pair/group used in clinical practice to treat breast cancer metastasis, to lipid-polymer nanoparticles (LPNs) loaded with silibinin. The molecular structure responsible for HG association with LPNs was assessed using surface-enhanced Raman spectroscopy for HNS surface chemistry characterization. Moreover, the molecular class of HG was identified using UPLC-Orbitrap-MS/MS to further confirm the surface binding. Mucus diffusion and in vivo biodistribution were evaluated using in vitro multiple-particle tracking and environment-responsive fluorescence probe in 4T1 tumor-bearing mice, respectively. The alleviation of breast cancer metastasis was assessed in 4T1 tumor-bearing mice, and the underlying mechanism was investigated.

Results

The HNS reduced particle-mucus interactions by altering hydrophilicity and surface characteristics compared to LPNs. The epithelium transportation of HNS and absorption through Peyer's patch in mice were improved, promoting their biodistribution in the lung and tumor tissues. Furthermore, the HNS alleviated lung metastasis by inducing cell apoptosis and regulating the expression of MMP-9 and TGF-β1, which altered the TME in 4T1 tumor-bearing mice.

Conclusion

HNS provides an appealing system with multi-component binding of herbal medicine to facilitate both oral nanoparticle delivery efficiency and the alleviation of lung metastasis. This strategy may potentially help improve treatment for patients with breast cancer.

A robust, flexible adhesive tape-based SERS substrate fabricated by polymer etching and subsequent Au coating on the exposed SiO2 nanosphere monolayer

With the rapid development of trace detection, high-performance flexible surface-enhanced Raman scattering (SERS) substrates have enjoyed steady growth of interest. In this paper, a facile method to improve the robustness of the flexible SERS substrate via the synergistic effect of rigid SiO₂ nanospheres and flexible tape was demonstrated for the first time. In detail, the spin-coated SiO₂ nanosphere monolayer was transferred from the host silicon wafer into the tape by peeling-off process, followed by O₂ plasma etching of tape polymer to expose the nanospheres, and final Au coating to form plentiful SERS "hotspots". The as-prepared SERS sample shows a detection limit of Rhodamine 6G (R6G) down to 10^-10 M and can afford a 500 times bending-releasing cyclic test. Our research provides a promising strategy to prepare robust SERS substrates which exhibit good potential in practical molecule detection on curved surfaces.

Analysis of Biomolecules Based on the Surface Enhanced Raman Spectroscopy

Analyzing biomolecules is essential for disease diagnostics, food safety inspection, environmental monitoring and pharmaceutical development. Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for detecting biomolecules due to its high sensitivity, rapidness and specificity in identifying molecular structures. This review focuses on the SERS analysis of biomolecules originated from humans, animals, plants and microorganisms, combined with nanomaterials as SERS substrates and nanotags. Recent advances in SERS detection of target molecules were summarized with different detection strategies including label-free and label-mediated types. This comprehensive and critical summary of SERS analysis of biomolecules might help researchers from different scientific backgrounds spark new ideas and proposals.