Tumor Microenvironment-Inspired Glutathione-Responsive Three-Dimensional Fibrous Network for Efficient Trapping and Gentle Release of Circulating Tumor Cells

Capture and lyase-triggered release of circulating tumor cells using a disposable microfluidic chip embedded with core/shell nylon-6/Ca(II)-alginate immunofiber mats

High-efficiency capture, release, and reculture of circulating tumor cells (CTCs) can significantly advance individualized cancer treatments. To achieve efficient CTC release without compromising their viability for subsequent reculture, an effective CTC capture/release system was developed. Nylon-6 (N6) and a cross-linked alginate hydrogel with Ca(II) were used as the shell and core, respectively, to prepare N6/Ca-Alg immunofiber mats using coaxial electrospinning. A 3 wt% concentration of Ca(II) was used to increase the viscosity of the alginate solution and generate a degradable coating on the N6 fiber. After modification with streptavidin and anti-EpCAM, the N6/Ca-Alg immunofiber mat was embedded within a disposable microfluidic chip to investigate the capture capacity of CTCs. The maximum adsorption capacity of CTCs was approximately 34 cells per mm2, while the viability of the captured cells was 95.1% after being released from the fibrous mats. The outer Ca-alginate hydrogel coating effectively enhanced the viability of the released cells for reculture. In spiked blood samples, our microfluidic system was able to specifically identify DLD1 cells from 10 mL of human whole blood at a concentration of 65.6 cells per mL with 67.9% efficiency within 30 minutes. Under the flow of alginate lyase solution at 0.4 mg mL-1, the reculture efficiency of the released cells after 7 days reached 274.5%. Our proposed method provides an ideal fibrous mat to be embedded within a microfluidic chip for capturing and releasing CTCs for precision medicine applications, using recultured CTCs in individualized anti-tumor therapies.

A three-site recognition cytosensor for accurate detection of circulating tumor cells based on novel branched Pt Au nanospheres and MnO2-GO-Au nanosheets

A novel electrochemical cytosensor was developed with a three-protein recognition strategy, employing branched Pt Au nanospheres (B-Pt-Au NPs) as tags and MnO2-GO-Au nanosheet-modified electrodes for circulating tumor cells (CTC) detection. This system integrates specific magnetic separation and CTC enrichment with sensitive electrochemical detection to identify rare A549 cells in whole blood. MnO2-GO-Au nanosheets, known for their high conductivity and biocompatibility, were used to modify a bare electrode, improving the electrochemical interface for biomolecules. The B-Pt-Au NPs could only approach the sensing interface and enhance the current signal through their specific electrocatalytic activity when all three specific proteins, i.e. mucin 1 (MUC1), epithelial cell adhesion molecule (EpCAM), and epidermal growth factor receptor (EGFR), of rare A549 cells in peripheral blood were simultaneously expressed on the cell membrane. The developed cytosensor demonstrated a detection limit as low as 1 cell mL⁻1 and, more importantly, could accurately distinguish A549 cells from other cancer cells. Thus, this proposed strategy offers a powerful tool for liquid biopsy analysis of extremely rare CTCs in complex peripheral blood, with potential applications in reliable early diagnosis of non-small cell lung cancer (NSCLC).

Local Delivery of Dual Stem Cell-Derived Exosomes Using an Electrospun Nanofibrous Platform for the Treatment of Traumatic Brain Injury

Traumatic brain injury poses serious physical, psychosocial, and economic threats. Although systemic administration of stem cell-derived exosomes has recently been proven to be a promising modality for traumatic brain injury treatment, they come with distinct drawbacks. Luckily, various biomaterials have been developed to assist local delivery of exosomes to improve the targeting of organs, minimize nonspecific accumulation in vital organs, and ensure the protection and release of exosomes. In this study, we developed an electrospun nanofibrous scaffold to provide sustained delivery of dual exosomes derived from mesenchymal stem cells and neural stem cells for traumatic brain injury treatment. The electrospun nanofibrous scaffold employed a functionalized layer of polydopamine on electrospun poly(ε-caprolactone) nanofibers, thereby enhancing the efficient incorporation of exosomes through a synergistic interplay of adhesive forces, hydrogen bonding, and electrostatic interactions. First, the mesenchymal stem cell-derived exosomes and the neural stem cell-derived exosomes were found to modulate microglial polarization toward M2 phenotype, play an important role in the modulation of inflammatory responses, and augment axonal outgrowth and neural repair in PC12 cells. Second, the nanofibrous scaffold loaded with dual stem cell-derived exosomes (Duo-Exo@NF) accelerated functional recovery in a murine traumatic brain injury model, as it mitigated the presence of reactive astrocytes and microglia while elevating the levels of growth associated protein-43 and doublecortin. Additionally, multiomics analysis provided mechanistic insights into how dual stem cell-derived exosomes exerted its therapeutic effects. These findings collectively suggest that our novel Duo-Exo@NF system could function as an effective treatment modality for traumatic brain injury using sustained local delivery of dual exosomes from stem cells.

Electrospun nanofibrous mats loaded with gemcitabine and cisplatin suppress bladder tumor growth by improving the tumor immune microenvironment

The perplexing issues related to positive surgical margins and the considerable negative consequences associated with systemic chemotherapy have posed ongoing challenges for clinicians, especially when it comes to addressing bladder cancer treatment. The current investigation describes the production of nanocomposites loaded with gemcitabine (GEM) and cisplatin (CDDP) through the utilization of electrospinning technology. In vitro and in vivo studies have provided evidence of the strong effectiveness in suppressing tumor advancement while simultaneously reducing the accumulation of chemotherapy drugs within liver and kidney tissues. Mechanically, the GEM and CDDP-loaded electrospun nanocomposites could effectively eliminate myeloid-derived suppressor cells (MDSCs) in tumor tissues, and recruit CD8+ T cells and NKp46+ NK cells to kill tumor cells, which can also effectively inhibit tumor microvascular formation. Our investigation into the impact of localized administration of chemotherapy through GEM and CDDP-loaded electrospun nanocomposites on the tumor microenvironment will offer novel insights for tackling tumors.

Stimuli-Responsive Polymer-Based Nanosystems for Cancer Theranostics

Stimuli-responsive polymers can respond to internal stimuli, such as reactive oxygen species (ROS), glutathione (GSH), and pH, biological stimuli, such as enzymes, and external stimuli, such as lasers and ultrasound, etc., by changing their hydrophobicity/hydrophilicity, degradability, ionizability, etc., and thus have been widely used in biomedical applications. Due to the characteristics of the tumor microenvironment (TME), stimuli-responsive polymers that cater specifically to the TME have been extensively used to prepare smart nanovehicles for the targeted delivery of therapeutic and diagnostic agents to tumor tissues. Compared to conventional drug delivery nanosystems, TME-responsive nanosystems have many advantages, such as high sensitivity, broad applicability among different tumors, functional versatility, and improved biosafety. In recent years, a great deal of research has been devoted to engineering efficient stimuli-responsive polymeric nanosystems, and significant improvement has been made to both cancer diagnosis and therapy. In this review, we summarize some recent research advances involving the use of stimuli-responsive polymer nanocarriers in drug delivery, tumor imaging, therapy, and theranostics. Various chemical stimuli will be described in the context of stimuli-responsive nanosystems. Accordingly, the functional chemical groups responsible for the responsiveness and the strategies to incorporate these groups into the polymer will be discussed in detail. With the research on this topic expending at a fast pace, some innovative concepts, such as sequential and cascade drug release, NIR-II imaging, and multifunctional formulations, have emerged as popular strategies for enhanced performance, which will also be included here with up-to-date illustrations. We hope that this review will offer valuable insights for the selection and optimization of stimuli-responsive polymers to help accelerate their future applications in cancer diagnosis and treatment.