The migration and invasion of endothelial-derived mesenchymal cells (EMCs) play a crucial role in both atherosclerotic plaque formation and cancer metastasis. However, current strategies aimed at suppressing EMC formation often suffer from poor specificity and undesirable side effects, and few efforts have directly targeted the migratory and invasive behaviors of EMCs. In this study, we present a nanoparticle-based strategy to specifically inhibit EMC migration and invasion using cadherin-2-targeted melanin nanoparticles in combination with a mild photothermal treatment. Cell migration and invasion assays demonstrate that the synergistic effect of nanoparticle uptake and photothermal treatment effectively impedes the EMC motility. Atomic force and super resolution microscopy indicate that this inhibition is associated with disruption of the actin cytoskeleton and consequent morphological alterations. Furthermore, Western blot analyses elucidate the underlying molecular mechanism, showing that cadherin-2-dependent RhoA activation is downregulated by the combined nanoparticle and photothermal treatment, leading to cytoskeletal disorganization. Overall, these in vitro findings serve as a proof-of-concept study for a potential alternative or complementary strategy to attenuate atherosclerotic plaque development and cancer metastasis by targeting the migration and invasion of EMCs from a mechanistic perspective.

Fibroblast-to-myofibroblast transition (FMT) is cellular transformation process driving the pathogenesis of fibrotic disorders such as pulmonary fibrosis and scleroderma. Despite advances in anti-fibrotic therapies, existing treatments primarily slow disease progression rather than directly targeting extracellular matrix (ECM)-secreting myofibroblasts, and cannot reverse established fibrosis. In this work, a nanoparticle-enabled, anti-fibrotic approach is demonstrated to reverse the FMT in myofibroblasts via targeting cadherin-2 (CDH2), a cell-surface maker of myofibroblasts, using melanin nanoparticles with surface-engineered CDH2 antibody (CDH2-MelNPs). Treatment with CDH2-MelNPs promotes myofibroblast-to-fibroblast transition (MFT, reversed FMT), significantly suppressing ECM deposition, proliferation, migration, and invasive behavior of myofibroblasts, while concurrently mitigating tissue contractility and stiffness, the hallmarks of fibrosis. Mechanistic studies reveal that this nanoparticle-driven MFT is regulated by the inhibition of the Rho signaling, a critical regulator of FMT. Overall, these findings propose an alternative therapeutic avenue to potentially halt or reverse a broad spectrum of fibrotic diseases. The manipulation of fibroblast/myofibroblast phenotype using nanoparticles may also serve as a promising tool in tissue engineering, enabling precise control over tissue remodeling.

1.EMT in cancer metastasis and chemoresistance Cancer metastasis is contingent on the epithelial-mesenchymal transition(EMT)of cancer cells.During EMT,epithelial cancer cells transform into a mesenchymal phenotype,which endows cancer cells with enhanced migratory and invasive abilities,promoting their dissemination throughout the body.EMT also contributes signifi-cantly to chemoresistance,allowing cancer cells to survive and metastasize even after chemotherapy[1].

High-grade serous tumors are immunologically cold, characterized by limited immune cell infiltration and reduced clinical outcome, primarily due to hypoxia and extensive extracellular matrix remodeling that disrupt tumor-stromal-immune interactions. However, current experimental models fail to fully capture oxygen and matrix microenvironmental features, limiting progress in understanding tumor-immune dynamics and developing effective treatments. Here, we demonstrate that patient-derived tumor-immune tunable models, mimicking physiologically relevant oxygen levels and extracellular matrix remodeling, recapitulate the hypoxia-induced stromal/matrix dysregulation, which causes impaired immune infiltration, and enable dissecting targeted opportunities via TGF-β signaling. The models integrate cancer cells co-cultured with cancer-associated fibroblasts and exposed to immune cells as multi-culture or challenged them to infiltrate into a 3D model bioengineered with autologous plasma from the matching patient or onto decellularized human ovaries. By bioengineering physiologically relevant oxygen levels of hypoxic tumors and physoxic ovaries, we uncovered that intratumoral hypoxia acts as a friend and a foe, causing hypoxia-induced stromal-driven impaired immune infiltration but enhancing the activation and cytotoxicity of CD8+ T cells. We also showed that targeting TGF-β signaling reversed the hypoxia-induced stromal-driven impaired immune infiltration. These human-relevant tunable models may aid the development of targeted therapies to turn immunologically cold tumors into hot ones.

Cancer metastasis is driven by the motility of cancer cells, a process governed by the actin cytoskeleton. However, current actin-disrupting drugs aimed at inhibiting cancer cell migration suffer from poor selectivity and off-target effects. In this study, we present core-shell metal-organic framework nanoparticles designed to specifically target and disrupt the actin cytoskeleton in migratory cancer cells. We demonstrate that the migration and invasion of breast and prostate cancer cells can be significantly inhibited by targeting a migration-associated surface marker, epithelial cell adhesion molecule (EpCAM), using low-dose EpCAM antibody functionalized zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs@Ab). Single-cell imaging reveals that the observed inhibition of cell migration results from disruption of the actin cytoskeleton. Mechanistic investigations highlight the synergistic roles of the degradable ZIF-8 nanoparticle core and the EpCAM-targeted antibody shell in cytoskeletal disruption. Given the widespread expression of cancer cell migration-related surface markers and the universal actin-disrupting activity of ZIF-8 NPs, this nanoparticle system provides a versatile, effective, and potentially safer strategy to inhibit cancer cell motility.

Epithelial-mesenchymal transition (EMT) of cancer cells plays a crucial role in cancer cell migration and N-cadherin is increasingly recognized to be a potential therapeutic target for regulating EMT and inhibiting cancer metastasis. However, traditional N-cadherin antagonists such as antibodies and peptides still face several issues associated with poor biostability, water solubility, and effectiveness. Here, we introduce a nanoparticle-based approach, namely, N-cadherin nano-antagonists and their moderate photothermal effect, to mediate mesenchymal-epithelial transition (MET) of cancer cells. The induced MET in cancer cells leads to their inhibited migration on planar surfaces, reduced invasion through three-dimensional extracellular matrix, decreased adhesion to endothelial cells, and minimized transmigration across endothelial barriers, all of which could potentially contribute to stopping cancer metastasis. The phenotype transition of cancer cells and its molecular mechanism are verified and elucidated by single cell imaging and immunoblotting techniques. Considering the broad availability of N-cadherin on various cancers, this approach offers a versatile, nanoparticle-based strategy to stop cancer cell migration by directing a specific phenotypic transition (i.e., MET) of cancer cells. Beyond the potential in cancer therapy, modulating phenotypic transition of N-cadherin-rich cells could lead to new tools for building non-animal models and tissue engineering applications.

We describe the utilization of a biopolymer-preserved plasmonic biosensor with improved environmental stability for the sensitive detection of prostate-specific antigen (PSA).

Endothelial-mesenchymal transition (EndoMT) of vascular endothelial cells has recently been considered as a key player in the early progression of a variety of vascular and nonvascular diseases, including atherosclerosis, cancer, and organ fibrosis. However, current strategies attempting to identify pharmacological inhibitors to block the regulatory pathways of EndoMT suffer from poor selectivity, unwanted side effects, and a heterogeneous response from endothelial cells with different origins. Furthermore, EndoMT inhibitors focus on preventing EndoMT, leaving the endothelial cells that have already undergone EndoMT unresolved. Here, we report the design of a simple but powerful nanoparticle system (i.e., N-cadherin targeted melanin nanoparticles) to convert cytokine-activated, mesenchymal-like endothelial cells back to their original endothelial phenotype. We term this process "Reversed EndoMT" (R-EndoMT). R-EndoMT allows the impaired endothelial barriers to recover their quiescence and intactness, with significantly reduced leukocyte and cancer cell adhesion and transmigration, which could potentially stop atheromatous plaque formation and cancer metastasis in the early stages. R-EndoMT is achieved on different endothelial cell types originating from arteries, veins, and capillaries, independent of activating cytokines. We reveal that N-cadherin targeted melanin nanoparticles reverse EndoMT by downregulating an N-cadherin dependent RhoA activation pathway. Overall, this approach offers a different prospect to treat multiple EndoMT-associated diseases by designing nanoparticles to reverse the phenotypical transition of endothelial cells.

The Enhanced Permeability and Retention (EPR) effect, an elevated accumulation of drugs and nanoparticles in tumors versus in normal tissues, is a widely used concept in the field of cancer therapy. It assumes that the vasculature of solid tumors would possess abnormal, leaky endothelial cell barriers, allowing easy access of intravenous-delivered drugs and nanoparticles to tumor regions. However, the EPR effect is not always effective owing to the heterogeneity of tumor endothelium over time, location, and species. Herein, we introduce a unique nanoparticle-based approach, using MUC18-targeted gold nanorods coupled with mild hyperthermia, to specifically enhance tumor endothelial permeability. This improves the efficacy of traditional cancer therapy including photothermal therapy and anticancer drug delivery by increasing the transport of photo-absorbers and drugs across the tumor endothelium. Using single cell imaging tools and classic analytical approaches in molecular biology, we demonstrate that MUC18-targeted gold nanorods and mild hyperthermia enlarge the intercellular gaps of tumor endothelium by inducing circumferential actin remodeling, stress fiber formation, and cell contraction of adjacent endothelial cells. Considering MUC18 is overexpressed on a variety of tumor endothelium and cancer cells, this approach paves a new avenue to improve the efficacy of cancer therapy by actively enhancing the tumor endothelial permeability.

Cytotoxicity of nanoparticles is routinely characterized by biochemical assays such as cell viability and membrane integrity assays. However, these approaches overlook cellular biophysical properties including changes in the actin cytoskeleton, cell stiffness, and cell morphology, particularly when cells are exposed to "non-cytotoxic" doses of nanoparticles. Zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs), a member of metal–organic framework family, has received increasing interest in various fields such as environmental and biomedical sciences. ZIF-8 NPs may enter the blood circulation system after unintended oral and inhalational exposure or intended intravenous injection for diagnostic and therapeutic applications, yet the effect of ZIF-8 NPs on vascular endothelial cells is not well understood. Here, the biophysical impact of "non-cytotoxic" dose ZIF-8 NPs on human aortic endothelial cells (HAECs) is investigated. We demonstrate that "non-cytotoxic" doses of ZIF-8 NPs, pre-defined by a series of biochemical assays, can increase the endothelial permeability of HAEC monolayers by causing cell junction disruption and intercellular gap formation, which can be attributed to actin reorganization within adjacent HAECs. Nanomechanical atomic force microscopy and super resolution fluorescence microscopy further confirm that "non-cytotoxic" doses of ZIF-8 NPs change the actin structure and cell morphology of HAECs at the single cell level. Finally, the underlying mechanism of actin reorganization induced by the "non-cytotoxic" dose ZIF-8 NPs is elucidated. Together, this study indicates that the "non-cytotoxic" doses of ZIF-8 NPs, intentionally or unintentionally introduced into blood circulation, may still pose a threat to human health, considering increased endothelial permeability is essential to the progression of a variety of diseases. From a broad view of cytotoxicity evaluation, it is important to consider the biophysical properties of cells, since they can serve as novel and more sensitive markers to assess nanomaterial's cytotoxicity.

Thecorrosion protection of MXene-based composite coatingsis challengingdue to the relatively low dispersion of MXene in organic coatings.In this work, waterborne polyurethane (WPU) composites containinghybrid nanoadditives of Ti3C2T (x) MXene and functionalized carbon nanotubes (CNTs) were fabricated.The thermal stability, surface hydrophobicity, surface roughness,and mechanical properties of the nanocomposites containing MXene orMXene/CNT hybrid additives were studied. Electrochemical methods,including electrochemical impedance spectroscopy (EIS) and potentiodynamicpolarization scans, were utilized to evaluate the anticorrosion propertiesof the nanocomposite coatings when applied to copper substrates. Thepolyurethane sample with 0.95 wt % Ti3C2T (x) MXene and 0.05 wt % CNTs showed the lowestcorrosion rate of 2.1 x 10(-3) & mu;m year(-1). Additionally, the EIS results revealed that thecorrosion resistance of WPU/MXene coatings significantly increasedby adding 0.05 wt % CNTs. The mechanism of the improved anticorrosionperformance of the WPU/MXene/CNT composite coating is illustrated.Moreover, the importance of optimizing the concentration of the CNTsis discussed to obtain better corrosion protection. The polyurethanenanocomposite coatings reported in this work present great potentialas corrosion protection coatings for metals and other surfaces.

Cytotoxicity of nanoparticles, typically evaluated by biochemical-based assays, often overlook the cellular biophysical properties such as cell morphology and cytoskeletal actin, which could serve as more sensitive indicators for cytotoxicity. Here, we demonstrate that low-dose albumin-coated gold nanorods (HSA@AuNRs), although being considered noncytotoxic in multiple biochemical assays, can induce intercellular gaps and enhance the paracellular permeability between human aortic endothelial cells (HAECs). The formation of intercellular gaps can be attributed to the changed cell morphology and cytoskeletal actin structures, as validated at the monolayer and single cell levels using fluorescence staining, atomic force microscopy, and super-resolution imaging. Molecular mechanistic study shows the caveolae-mediated endocytosis of HSA@AuNRs induces the calcium influx and activates actomyosin contraction in HAECs. Considering the important roles of endothelial integrity/dysfunction in various physiological/pathological conditions, this work suggests a potential adverse effect of albumin-coated gold nanorods on the cardiovascular system. On the other hand, this work also offers a feasible way to modulate the endothelial permeability, thus promoting drug and nanoparticle delivery across the endothelium.

Cancer stem-like cells (CSCs) play key roles in chemoresistance, tumor metastasis, and clinical relapse. However, current CSC inhibitors lack specificity, efficacy, and applicability to different cancers. Herein, we introduce a nanomaterial-based approach to photothermally induce the differentiation of CSCs, termed "photothermal differentiation", leading to the attenuation of cancer cell stemness, chemoresistance, and metastasis. MoS2 nanosheets and a moderate photothermal treatment were applied to target a CSC surface receptor (i.e., CD44) and modulate its downstream signaling pathway. This treatment forces the more stem-like cancer cells to lose the mesenchymal phenotype and adopt an epithelial, less stem-like state, which shows attenuated self-renewal capacity, more response to anticancer drugs, and less invasiveness. This approach could be applicable to various cancers due to the broad availability of the CD44 biomarker. The concept of using photothermal nanomaterials to regulate specific cellular activities driving the differentiation of CSCs offers a new avenue for treating refractory cancers.

Understanding the specific mechanisms responsible for anabolic and catabolic responses to static or dynamic force are largely poorly understood. Because of this, most research groups studying mechanotransduction due to dynamic forces employ an empirical approach in deciding what frequencies to apply during experiments. While this has been shown to elucidate valuable information regarding how cells respond under controlled provocation, it is often difficult or impossible to determine a true optimal frequency for force application, as many intracellular complexes are involved in receiving, propagating, and responding to a given stimulus. Here we present a novel adaptation of an analytical technique from the fields of civil and mechanical engineering that may open the door to direct measurement of mechanobiological cellular frequencies which could be used to target specific cell signaling pathways leveraging synergy between outside-in and inside-out mechanotransduction approaches. This information could be useful in identifying how specific proteins are involved in the homeostatic balance, or disruption thereof, of cells and tissue, furthering the understanding of the pathogenesis and progression of many diseases across a wide variety of cell types, which may one day lead to the development of novel mechanobiological therapies for clinical use.

Cancer metastasis leads to most deaths in cancer patients, and the epithelial-mesenchymal transition (EMT) is the key mechanism that endows the cancer cells with strong migratory and invasive abilities. Here, we present a nanomaterial-based approach to reverse the EMT in cancer cells by targeting an EMT inducer, CD146, using engineered black phosphorus nanosheets (BPNSs) and a mild photothermal treatment. We demonstrate this approach can convert highly metastatic, mesenchymal-type breast cancer cells to an epithelial phenotype (i.e., reversing EMT), leading to a complete stoppage of cancer cell migration. By using advanced nanomechanical and super-resolution imaging, complemented by immunoblotting, we validate the phenotypic switch in the cancer cells, as evidenced by the altered actin organization and cell morphology, downregulation of mesenchymal protein markers, and upregulation of epithelial protein markers. We also elucidate the molecular mechanism behind the reversal of EMT. Our results reveal that CD146-targeted BPNSs and a mild photothermal treatment synergistically contribute to EMT reversal by downregulating membrane CD146 and perturbing its downstream EMT-related signaling pathways. Considering CD146 overexpression has been confirmed on the surface of a variety of metastatic, mesenchymal-like cancer cells, this approach could be applicable for treating various cancer metastasis via modulating the phenotype switch in cancer cells.

Zeolitic imidazolate framework-8 (ZIF-8) nanoparticles have emerged as a promising platform for drug delivery and controlled release. Considering most ZIF-8 nanoparticle drug carriers are designed to be administered intravenously, and thus would directly contact vascular smooth muscle cells (VSMCs) in many circumstances, the potential interactions of ZIF-8 nanoparticles with VSMCs require investigation. Here, the effects of low doses of ZIF-8 nanoparticles on VSMC morphology, actin organization, and contractility are investigated. Two nanoscale imaging tools, atomic force microscopy, and direct stochastic optical reconstruction microscopy, show that even at the concentrations (12.5 and 25 µg/ml) that were deemed “safe” by conventional biochemical cell assays (MTT and LDH assays), ZIF-8 nanoparticles can still cause changes in cell morphology and actin cytoskeleton organization at the cell apical and basal surfaces. These cytoskeletal structural changes impair the contractility function of VSMCs in response to Angiotensin II, a classic vasoconstrictor. Based on intracellular zinc and actin polymerization assays, we conclude that the increased intracellular Zn2+ concentration due to the uptake and dissociation of ZIF-8 nanoparticles could cause the actin cytoskeleton dis-organization, as the elevated Zn2+ directly disrupts the actin assembly process, leading to altered actin organization such as branches and networks. Since the VSMC phenotype change and loss of contractility are fundamental to the development of atherosclerosis and related cardiovascular diseases, it is worth noting that these low doses of ZIF-8 nanoparticles administered intravenously could still be a safety concern in terms of cardiovascular risks. Moving forward, it is imperative to re-consider the “safe” nanoparticle dosages determined by biochemical cell assays alone, and take into account the impact of these nanoparticles on the biophysical characteristics of VSMCs, including changes in the actin cytoskeleton and cell morphology.

Cluster of differentiation 146 (CD146), a cancer cell adhesion molecule, is over-expressed on the surfaces of melanoma, breast, ovarian, and prostate cancer cells, and its high expression indicates the migration tendency of these cancer cells and poor patient prognosis. Here, we hypothesize that targeting the CD146 with low-dose gold nanorods combined with mild hyperthermia can stop the migration of these cancer cells. Two metastatic cancer cells including a melanoma and a breast cancer cell line are selected as the model systems. Cell migration assays show that the migration of both cell lines can be completely stopped by the treatment. Atomic force microscopy and super resolution fluorescence microscopy reveal the alterations of actin cytoskeleton and cell morphology correspond to the inhibited cell migration. Further mechanistic analysis indicates the treatment disrupts the actin cytoskeleton by a synergistic mechanism including depleting membrane CD146 and interfering ezrin-radixin-moesin phosphorylation. As a result, we believe targeting CD146 with low-dose gold nanorods and mild hyperthermia could be a versatile, effective, and safe approach for stopping cancer metastasis. More broadly, the concept of targeting cancer cell surface markers that connect the underlying actin cytoskeleton, offers enormous potential in treating cancer metastasis, which accounts for more than 90% of cancer-associated mortality.

Immunoassays typically must be stored under refrigerated conditions because antibodies, after being immobilized to solid surfaces, tend to lose their recognition capabilities to target antigens under non-refrigerated conditions. This requirement hinders application of immunoassays in resource-limited settings including rural clinics in tropical regions, disaster struck areas, and low-income countries, where refrigeration may not be feasible. In this work, a facile approach based on a reversable zeolitic imidazolate framework-8 (ZIF-8) coating is introduced to stabilize surface-bound antibodies on enzyme-linked immunosorbent assay (ELISA) plates under non-refrigerated conditions. Using a sandwich ELISA for the detection of neutrophil gelatinase-associated lipocalin (NGAL), a urine biomarker for acute kidney injury, as a model system, ZIF-8 is demonstrated to be able to uniformly coat the surface-bound anti-NGAL IgG, and stabilize the dynamic range and detection sensitivity of the assay after storage at an elevated temperature (50 °C) for at least 4 weeks. The stabilization efficacy of the ZIF-8 coating is comparable to the current "gold standard" refrigeration approach, and superior to the commonly used sucrose coating method. This approach will greatly improve the shelf-life and stability of antibody-coated ELISAs and other types of assays which utilize surface-bound antibodies, thus extending biomedical research and medical diagnostics to resource-limited settings.

Transmembrane MUC18 is highly expressed on most metastatic cancers. Herein, we demonstrate that targeting MUC18 with polydopamine nanoparticles (PDA NPs) and a mild photothermal effect can completely cease the migration of melanoma and breast cancer cells without killing the cells. The inhibited cell migration can be attributed to the altered actin cytoskeleton, cell stiffness, and cell morphology, as revealed by nanomechanical and super resolution fluorescence imaging techniques. Further mechanistic studies at the molecular level show that MUC18 targeted PDA NPs and a mild photothermal treatment produce a synergistic effect on the actin cytoskeleton by downregulating the transmembrane MUC18 and interrupting ezrin-radixin-moesin phosphorylation, thereby releasing the actin cytoskeleton from the cell membrane and compromising force transduction through the actin cytoskeleton to the transmembrane MUC18. Overall, the concept of targeting transmembrane metastatic markers and disrupting their downstream effectors (i.e., actin and actin-binding proteins) opens up a new avenue to cancer therapy.