Chitosan and hyaluronic acid in breast cancer treatment: Anticancer efficacy and nanoparticle and hydrogel development

The pervasive global health concern of breast cancer necessitates the development of innovative therapeutic interventions to enhance efficacy and mitigate adverse effects. Chitosan and hyaluronic acid, recognized for their biocompatibility and biodegradability, present compelling options for the novel drug delivery systems and therapeutic platforms in the context of breast cancer management. This review will delineate the distinctive attributes of chitosan and hyaluronic acid, encompassing their inherent anticancer properties, targeting capabilities, and suitability for chemical modifications along with nanoparticle development. These characteristics render them exceptionally well-suited for the fabrication of nanoparticles and hydrogels. The intrinsic anticancer potential of chitosan, in conjunction with its mucoadhesive properties, and the robust binding affinity of hyaluronic acid to CD44 receptors, facilitate specific drug delivery to the malignant cells, thus circumventing the limitations inherent in traditional treatment modalities such as chemotherapy. The incorporation of these materials into nanocarriers allows for the co-delivery of therapeutic agents, thereby potentiating synergistic effects, while hydrogel systems provide localized, controlled drug release and facilitate tissue regeneration. An analysis of advancements in their synthesis, functionalization, and application is presented, while also acknowledging challenges pertaining to scalability and clinical translation.

Bioactive modification of cyclic olefin copolymer (COC) film surfaces by hyaluronic acid and chitosan for enhanced cell adhesion

Cyclic olefin copolymer (COC) has recently emerged as an attractive material in biomedical fields for its high purity, excellent stability and chemical resistance, particularly in applications of microfluidic chips, prefilled syringes and bone regeneration. However, the high hydrophobicity of COC has inhibited the adhesion of cells and biological macromolecules, such as proteins, etc., significantly limiting its broader applications. In this study, we propose a new method to modify COC surfaces by sequential coating with polydopamine (PDA) followed by hyaluronic acid (HA) or O-carboxymethyl chitosan (CMC), while comparing the impacts of the positively charged HA and negatively charged CMC on protein adsorption and cell adhesion. FTIR and XPS measurements confirmed the successful modification on COC films, resulting in surfaces with highly increased hydrophilicity, anti-oxidative properties, and improved protein adsorption. Moreover, negatively charged HA, with signal transduction capabilities showed a greater effect in promoting cell adhesion. Thus, we present a straightforward strategy for enhancing the hydrophilicity of COC surfaces, offering new insights into COC modification and potential biomedical applications.

Polydopamine nanomaterials and their potential applications in the treatment of autoimmune diseases

The conventional treatment methods used for the management of autoimmune diseases (ADs) have limited efficacy and also exhibit significant side effects. Thus, identification of novel strategies to improve the efficacy and safety of ADs treatment is urgently required. Overactivated immune response and oxidative stress are common characteristics associated with ADs. Polydopamine (PDA), as a polymer material with good antioxidant and photothermal conversion properties, has displayed useful application potential against ADs. In addition, PDA possesses good biosafety, simple preparation, and easy functionalization, which is conducive for the pharmacological development of PDA nanomaterials with clinical transformation prospects. Here, we have first reviewed the preparation of PDA, the different functional integration strategies of PDA-based biomaterials, and their potential applications in ADs. Next, the mechanism of action of PDA in ADs has been elaborated in detail. Finally, the application opportunities and challenges linked with PDA nanomaterials for ADs treatment are discussed. This review is contributed to design reasonable and effective PDA nanomaterials for the diagnosis and treatment of ADs.

Dual-sensitive and highly biocompatible O-carboxymethyl chitosan nanodroplets for prostate tumor ultrasonic imaging and treatment

Nanosized drug delivery systems have rapidly emerged as a promising approach to tumor therapy, which still have many challenges in clinical application. In this study, doxorubicin-loaded O-carboxymethyl chitosan/perfluorohexane nanodroplets (O-CS-DOX NDs) were synthesized and functionally tested as an effective drug delivery system in vitro and in vivo. O-CS-DOX NDs with small size (159.6 nm) and good doxorubicin encapsuling ability showed pH- and ultrasound-dependent drug release profile and satisfying ultrasound imaging performance. With high biocompatibility and biosafety, these nanodroplets could accumulate in the tumor sites and exhibit high efficiency in inhibiting tumor growth with ultrasound irradiation. These stable, safe and smart O-CS-DOX NDs showed promising potential as a smart dual-responsive bomb for tumor ultrasonic imaging and treatment.

Hyaluronic acid-empowered nanotheranostics in breast and lung cancers therapy

Nanomedicine application in cancer therapy is an urgency because of inability of current biological therapies for complete removal of tumor cells. The development of smart and novel nanoplatforms for treatment of cancer can provide new insight in tumor suppression. Hyaluronic acid is a biopolymer that can be employed for synthesis of smart nanostructures capable of selective targeting CD44-overexpressing tumor cells. The breast and lung cancers are among the most malignant and common tumors in both females and males that environmental factors, lifestyle and genomic alterations are among the risk factors for their pathogenesis and development. Since etiology of breast and lung tumors is not certain and multiple factors participate in their development, preventative measures have not been completely successful and studies have focused on developing new treatment strategies for them. The aim of current review is to provide a comprehensive discussion about application of hyaluronic acid-based nanostructures for treatment of breast and lung cancers. The main reason of using hyaluronic acid-based nanoparticles is their ability in targeting breast and lung cancers in a selective way due to upregulation of CD44 receptor on their surface. Moreover, nanocarriers developed from hyaluronic acid or functionalized with hyaluronic acid have high biocompatibility and their safety is appreciated. The drugs and genes used for treatment of breast and lung cancers lack specific accumulation at cancer site and their cytotoxicity is low, but hyaluronic acid-based nanostructures provide their targeted delivery to tumor site and by increasing internalization of drugs and genes in breast and lung tumor cells, they improve their therapeutic index. Furthermore, hyaluronic acid-based nanostructures can be used for phototherapy-mediated breast and lung cancers ablation. The stimuli-responsive and smart kinds of hyaluronic acid-based nanostructures such as pH- and light-responsive can increase selective targeting of breast and lung cancers.

Hyaluronic Acid-Conjugated Fluorescent Probe-Shielded Polydopamine Nanomedicines for Targeted Imaging and Chemotherapy of Bladder Cancer

Bladder cancer is one of the most common malignancies in the urinary system, with high risk of recurrence and progression. However, the difficulty in detecting small tumor lesions and the lack of selectivity of intravesical treatment seriously affect the prognosis of patients with bladder cancer. In the present work, a nanoparticle-based delivery system with tumor targeting, high biocompatibility, simple preparation, and the ability to synergize imaging and therapy was fabricated. Specifically, this nanosystem consisted of the core of doxorubicin (DOX)-loaded polydopamine nanoparticles (PDD NPs) and the shell of hyaluronic acid (HA)-conjugated IR780 (HA-IR780). The HA-IR780-covered PDD NPs (HR-PDD NPs) demonstrated tumor targeting and visualization both in vitro and in vivo with properties of promoted cancer cell endocytosis and lysosomal escape, efficiently delivering drugs to the target site and exerting a killing effect on tumor cells. Encouragingly, intravesical instillation of HR-PDD NPs improved drug retention in the bladder and promoted its accumulation in tumor tissue, resulting in better tumor proliferation inhibition and apoptosis in an orthotopic bladder cancer model in rats. This study provides a promising strategy for the diagnosis and therapy of bladder cancer.

Multifunctional polysaccharide nanoprobes for biological imaging

Imaging and tracking biological targets or processes play an important role in revealing molecular mechanisms and disease states. Bioimaging via optical, nuclear, or magnetic resonance techniques enables high resolution, high sensitivity, and high depth imaging from the whole animal down to single cells via advanced functional nanoprobes. To overcome the limitations of single-modality imaging, multimodality nanoprobes have been engineered with a variety of imaging modalities and functionalities. Polysaccharides are sugar-containing bioactive polymers with superior biocompatibility, biodegradability, and solubility. The combination of polysaccharides with single or multiple contrast agents facilitates the development of novel nanoprobes with enhanced functions for biological imaging. Nanoprobes constructed with clinically applicable polysaccharides and contrast agents hold great potential for clinical translations. This review briefly introduces the basics of different imaging modalities and polysaccharides, then summarizes the recent progress of polysaccharide-based nanoprobes for biological imaging in various diseases, emphasizing bioimaging with optical, nuclear, and magnetic resonance techniques. The current issues and future directions regarding the development and applications of polysaccharide nanoprobes are further discussed.

Quercetin@Gd3+ doped Prussian blue nanocubes induce the pyroptotic death of MDA-MB-231 cells: combinational targeted multimodal therapy, dual modal MRI, intuitive modelling of r1-r2 relaxivities

Quercetin (Qu), a potential bioflavonoid has gained considerable interest as a promising chemotherapeutic drug which can inhibit the proliferation of triple-negative breast cancer (TNBC) cells due to its regulation of the expression of tumor-suppressor gene metastasis and antioxidant property. Notably, Qu exhibits a very negligible cytotoxic effect on normal cells, even with high-dose treatment, while it is shows high affinity to TNBC. However, the efficiency of Qu is limited clinically due to its poor bioavailability, caused by its low aqueous solubility (2.15 μg mL^-1 at 25 °C), rapid gastrointestinal digestion and chemical instability in alkaline and neutral media. Herein, polydopamine (PDA)-coated, NH₂-PEG-NH₂ and hyaluronic acid (HA)-functionalized Gd³⁺-doped Prussian blue nanocubes (GPBNC) are reported as a multifunctional platform for the codelivery of Qu as a chemotherapeutic agent and GPBNC as a photodynamic (PDT) and photothermal (PTT) agent with improved therapeutic efficiency to overcome theses barriers. PDA, NH₂-PEG-NH₂ and HA stabilize GPBNC@Qu and facilitate bioavailability and active-targeting, while absorption of near infrared (NIR) (808 nm; 1 W cm^-2) induces PDT and PTT activities and dual T₁-T₂-weighted magnetic resonance imaging (MRI) with high relaxometric parameters (r₁ 10.06 mM^-1 s^-1 and r₂ 24.96 mM^-1 s^-1 at a magnetic field of 3 T). The designed platform shows a pH-responsive Qu release profile and NIR-induced therapeutic efficiency of ∼79% in 20 minutes of irradiation, wherein N-terminal gardermin D (N-GSDMD) and a P2X7-receptor-mediated pyroptosis pathway induces cell death, corroborating the up-regulation of NLRP3, caspase-1, caspase-5, N-GSDMD, IL-1β, cleaved Pannexin-1 and P2X7 proteins. More interestingly, the increasing relaxivity values of Prussian blue nanocubes with Gd³⁺ doping have been explained on the basis of Solomon-Bloembergen-Morgan theory, considering inner- and outer-sphere relaxivity, wherein crystal defects, coordinated water molecules, tumbling rate, metal to water proton distance, correlation time, magnetisation value etc. play a significant role. In summary, our study suggests that GPBNC could be a beneficial nanocarrier for theranostic purposes against TNBC, while our conceptual study clearly demonstrates the role of various factors in increasing relaxometric parameters.

Recent applications of phase-change materials in tumor therapy and theranostics

Phase-change materials (PCMs) are a type of special material which can store and release a large amount of thermal energy without any significant temperature change. They are emerging in recent years as a promising functional material in tumor therapy and theranostics due to their accurate responses to the temperature variations, biocompatibility and low toxicity. In this review, we will introduce the main types of PCMs and their desirable physiochemical properties for biomedical applications, and highlight the recent progress of PCM's applications in the modulated release of antitumor drugs, with special attentions paid to various ways to initiate temperature-dependent phase change, the concomitant thermal therapy and its combination with or activation of other therapies, particularly unconventional therapies. We will also summarize PCM's recent applications in tumor theranostics, where both drugs and imaging probes are delivered by PCMs for controlled drug release and imaging-guided therapy. Finally, the future perspectives and potential limitations of harnessing PCMs in tumor therapy will be discussed.

Microfluidic Methods for Generation of Submicron Droplets: A Review

Submicron droplets are ubiquitous in nature and widely applied in fields such as biomedical diagnosis and therapy, oil recovery and energy conversion, among others. The submicron droplets are kinetically stable, their submicron size endows them with good mobility in highly constricted pathways, and the high surface-to-volume ratio allows effective loading of chemical components at the interface and good heat transfer performance. Conventional generation technology of submicron droplets in bulk involves high energy input, or relies on chemical energy released from the system. Microfluidic methods are widely used to generate highly monodispersed micron-sized or bigger droplets, while downsizing to the order of 100 nm was thought to be challenging because of sophisticated nanofabrication. In this review, we summarize the microfluidic methods that are promising for the generation of submicron droplets, with an emphasize on the device fabrication, operational condition, and resultant droplet size. Microfluidics offer a relatively energy-efficient and versatile tool for the generation of highly monodisperse submicron droplets.

Experimental study on the optimization of ANM33 release in foam cells

Given the miR-33's mechanistic relationships with multiple etiological factors in the pathogenesis of atherosclerosis (AS), we investigated the therapeutic potentials of dual-targeted microbubbles (HA-PANBs) in foam cell-specific release of anti-miR-33 (ANM33) oligonucleotides, resulting in the early prevention of AS progression and severity. The intracellular localization, loading optimization, and therapeutic effects of HA-PANBs were examined in detail in a co-cultured cell model of phagocytosis. Compared with non-targeting nanobubbles (NBs) and single-targeted microbubbles as controls, HA-PANBs efficiently delivered the ANM33 specifically to foam cells via sustained release, exhibiting its clinical value in mediating RNA silencing. Moreover, when used at a dose of 12 µg/mL HA-PANBs per 10⁷ cells for 48 h, a higher release rate and drug efficacy were observed. Therefore, HA-PANBs, effectively targeting early AS foam cells, may represent a novel and optimal gene therapy approach for AS management.

Next-Generation Colloidal Materials for Ultrasound Imaging Applications

Ultrasound has important applications, predominantly in the field of diagnostic imaging. Presently, colloidal systems such as microbubbles, phase-change emulsion droplets and particle systems with acoustic properties and multiresponsiveness are being developed to address typical issues faced when using commercial ultrasound contrast agents, and to extend the utility of such systems to targeted drug delivery and multimodal imaging. Current technologies and increasing research data on the chemistry, physics and materials science of new colloidal systems are also leading to the development of more complex, novel and application-specific colloidal assemblies with ultrasound contrast enhancement and other properties, which could be beneficial for multiple biomedical applications, especially imaging-guided treatments. In this article, we review recent developments in new colloids with applications that use ultrasound contrast enhancement. This work also highlights the emergence of colloidal materials fabricated from or modified with biologically derived and bio-inspired materials, particularly in the form of biopolymers and biomembranes. Challenges, limitations, potential developments and future directions of these next-generation colloidal systems are also presented and discussed.

Enhanced photoacoustic imaging in tissue-mimicking phantoms using polydopamine-shelled perfluorocarbon emulsion droplets

The current work features process parameters for the ultrasound (25 kHz)-assisted fabrication of polydopamine-shelled perfluorocarbon (PDA/PFC) emulsion droplets with bimodal (modes at 100-600 nm and 1-6 µm) and unimodal (200-600 nm) size distributions. Initial screening of these materials revealed that only PDA/PFC emulsion droplets with bimodal distributions showed photoacoustic signal enhancement due to large size of their optically absorbing PDA shells. Performance of this particular type of emulsion droplets as photoacoustic agents were evaluated in Intralipid®-India ink media, mimicking the optical scattering and absorbanceof various tissuetypes. From these measurements, it was observed that PDA/PFC droplets with bimodal size distributions can enhance the photoacoustic signal of blood-mimicking phantom by up to five folds in various tissue-mimicking phantoms with absorption coefficients from 0.1 to 1.0 cm^-1. Furthermore, using the information from enhanced photoacoustic images at 750 nm, the ultimate imaging depth was explored for polydopamine-shelled, perfluorohexane (PDA/PFH) emulsion droplets by photon trajectory simulations in 3D using a Monte Carlo approach. Based on these simulations, maximal tissue imaging depths for PDA/PFH emulsion droplets range from 10 to 40 mm, depending on the tissue type. These results demonstrate for the first time that ultrasonically fabricated PDA/PFC emulsion droplets have great potential as photoacoustic imaging agents that can be complemented with other reported characteristics of PDA/PFC emulsion droplets for extended applications in theranostics and other imaging modalities.

Fucoidan (Undaria pinnatifida)/Polydopamine Composite-Modified Surface Promotes Osteogenic Potential of Periodontal Ligament Stem Cells

Fucoidan, a marine-sulfated polysaccharide derived from brown algae, has been recently spotlighted as a natural biomaterial for use in bone formation and regeneration. Current research explores the osteoinductive and osteoconductive properties of fucoidan-based composites for bone tissue engineering applications. The utility of fucoidan in a bone tissue regeneration environment necessitates a better understanding of how fucoidan regulates osteogenic processes at the molecular level. Therefore, this study designed a fucoidan and polydopamine (PDA) composite-based film for use in a culture platform for periodontal ligament stem cells (PDLSCs) and explored the prominent molecular pathways induced during osteogenic differentiation of PDLSCs through transcriptome profiling. Characterization of the fucoidan/PDA-coated culture polystyrene surface was assessed by scanning electron microscopy and X-ray photoelectron spectroscopy. The osteogenic differentiation of the PDLSCs cultured on the fucoidan/PDA composite was examined through alkaline phosphatase activity, intracellular calcium levels, matrix mineralization assay, and analysis of the mRNA and protein expression of osteogenic markers. RNA sequencing was performed to identify significantly enriched and associated molecular networks. The culture of PDLSCs on the fucoidan/PDA composite demonstrated higher osteogenic potency than that on the control surface. Differentially expressed genes (DEGs) (n = 348) were identified during fucoidan/PDA-induced osteogenic differentiation by RNA sequencing. The signaling pathways enriched in the DEGs include regulation of the actin cytoskeleton and Ras-related protein 1 and phosphatidylinositol signaling. These pathways represent cell adhesion and cytoskeleton organization functions that are significantly involved in the osteogenic process. These results suggest that a fucoidan/PDA composite promotes the osteogenic potential of PDLSCs by activation of critical molecular pathways.

Controllable formation of bulk perfluorohexane nanodroplets by solvent exchange

Perfluorocarbon (PFC) nanodroplets have rapidly developed into useful ultrasound imaging agents in modern medicine due to their non-toxic and stable chemical properties that facilitate disease diagnosis and targeted therapy. In addition, with the good capacity for carrying breathing gases and the anti-infection ability, they are employed as blood substitutes and are the most ideal liquid respirators. However, it is still a challenge to prepare stable PFC nanodroplets of uniform size and high concentration for their efficient use. Herein, we developed a simple and highly reproducible method, i.e., propanol-water exchange, to prepare highly homogeneous and stable perfluorohexane (PFH) bulk nanodroplets. Interestingly, the size distribution and concentration of formed nanodroplets could be regulated by controlling the volume fraction of PFH and percentage of propanol in the propanol-water mixture. We demonstrated good reproducibility in the formation of bulk nanodroplets with PFH volume fractions of 1/2000-1/200 and propanol percentage of 5-40%, with uniform particle size distribution and high droplet concentration. Also, the prepared nanodroplets were very stable and could survive for several hours. We constructed a ternary phase diagram to describe the relationship between the PFH volume ratio, propanol concentration, and the size distribution and concentration of the formed PFH nanodroplets. This study provides a very useful method to prepare uniform size, high concentration and stable PFC nanodroplets for their medical applications.

Recent developments in mesoporous polydopamine-derived nanoplatforms for cancer theranostics

Polydopamine (PDA), which is derived from marine mussels, has excellent potential in early diagnosis of diseases and targeted drug delivery owing to its good biocompatibility, biodegradability, and photothermal conversion. However, when used as a solid nanoparticle, the application of traditional PDA is restricted because of the low drug-loading and encapsulation efficiencies of hydrophobic drugs. Nevertheless, the emergence of mesoporous materials broaden our horizon. Mesoporous polydopamine (MPDA) has the characteristics of a porous structure, simple preparation process, low cost, high specific surface area, high light-to-heat conversion efficiency, and excellent biocompatibility, and therefore has gained considerable interest. This review provides an overview of the preparation methods and the latest applications of MPDA-based nanodrug delivery systems (chemotherapy combined with radiotherapy, photothermal therapy combined with chemotherapy, photothermal therapy combined with immunotherapy, photothermal therapy combined with photodynamic/chemodynamic therapy, and cancer theranostics). This review is expected to shed light on the multi-strategy antitumor therapy applications of MPDA-based nanodrug delivery systems.

Aptamer-conjugated mesoporous polydopamine for docetaxel targeted delivery and synergistic photothermal therapy of prostate cancer

Objectives

It is imperative to develop efficient strategies on the treatment of prostate cancer. Here, we constructed multifunctional nanoparticles, namely AS1411@MPDA‐DTX (AMD) for targeted and synergistic chemotherapy/photothermal therapy of prostate cancer.

Materials and Methods

Mesoporous polydopamine (MPDA) nanoparticles were prepared by a one‐pot synthesis method, DTX was loaded through incubation, and AS1411 aptamer was modified onto MPDA by the covalent reaction. The prepared nanoparticles were characterized by ultra‐micro spectrophotometer, Fourier transform infrared spectra, transmission electron microscope, and so on. The targeting ability was detected by selective uptake and cell killing. The mechanism of AMD‐mediated synergistic therapy was detected by Western blot and immunofluorescence.

Results

The prepared nanoparticles can be easily synthesized and possessed excellent water solubility, stability, and controlled drug release ability, preferentially in acidic context. Based on in vitro and in vivo results, the nanoparticles can efficiently target prostate cancer cells, promote DTX internalization, and enhance the antitumor effects of chemo‐photothermal therapy strategies under the NIR laser irradiation.

Conclusions

As a multifunctional nanoplatform, AS1411@MPDA‐DTX could efficiently target prostate cancer cells, promote DTX internalization, and synergistically enhance the antiprostate cancer efficiency by combining with NIR irradiation.

Tracking the heat-triggered phase change of polydopamine-shelled, perfluorocarbon emulsion droplets into microbubbles using neutron scattering

Perfluorocarbon emulsion droplets are hybrid colloidal materials with vast applications, ranging from imaging to drug delivery, due to their controllable phase transition into microbubbles via heat application or acoustic droplet vapourisation. The current work highlights the application of small- and ultra-small-angle neutron scattering (SANS and USANS), in combination with contrast variation techniques, in observing the in situ phase transition of polydopamine-shelled, perfluorocarbon (PDA/PFC) emulsion droplets with controlled polydispersity into microbubbles upon heating. We correlate these measurements with optical and transmission electron microscopy imaging, dynamic light scattering, and thermogravimetric analysis to characterise these emulsions, and observe their phase transition into microbubbles. Results show that the phase transition of PDA/PFC droplets with perfluorohexane (PFH), perfluoropentane (PFP), and PFH-PFP mixtures occur at temperatures that are around 30-40 °C higher than the boiling points of pure liquid PFCs, and this is influenced by the specific PFC compositions (perfluorohexane, perfluoropentane, and mixtures of these PFCs). Analysis and model fitting of neutron scattering data allowed us to monitor droplet size distributions at different temperatures, giving valuable insights into the transformation of these polydisperse, emulsion droplet systems.

Functional ultrasound-triggered phase-shift perfluorocarbon nanodroplets for cancer therapy

In recent years, because of their unique properties, the use of perfluorocarbon nanodroplets (PFC NDs) in ultrasound-mediated tumor theranostics has attracted increasing interest. PFC is one of the most stable organic compounds with high hydrophobicity. Phase-shift PFC NDs can be transformed into highly echogenic microbubbles for ultrasound and photoacoustic imaging by ultrasound and laser light. In addition, in the process of acoustic droplet vaporization, PFC NDs with cavitation nuclei can be combined with a variety of ultrasound technologies to produce cavitation effects for tumor ablation, antivascular therapy and release of therapeutic agents loaded in nanodroplets. Moreover, they can also be used to overcome tumor hypoxia by virtue of high oxygen solubility. In this review, first the preparation and stabilization of PFC NDs are summarized and then the issues and outlook are discussed. More importantly, multifunctional platforms based on PFC NDs for cancer diagnostics, therapy and theranostics are reviewed in detail.

Ultrasmall MoS2 nanodots-wrapped perfluorohexane nanodroplets for dual-modal imaging and enhanced photothermal therapy

Development of a multifunctional nanotherapeutic agent with high contrast-enhanced dual-modal imaging and photothermal therapy (PTT) efficacy is of great interest. Combination of ultrasound (US) and computed tomography (CT) imaging offers high spatial resolution images, showing great potential in medical imaging. Herein, the semiconducting perfluorohexane (PFH) nanodroplets, MoS₂-PFH-PLLAs, are developed by stabilizing PFH droplets with the coating shell of poly (lactic-co-glycolic acid) (PLLA) and encapsulating the droplets with photoabsorbers of ultrasmall molybdenum disulfide (MoS₂) nanodots. Upon near-infrared (NIR) irradiation, the MoS₂-PFH-PLLAs can absorb the NIR light and convert it into heat, which not only promotes liquid-to-gas phase transition of PFH but also triggers photothermal heating, resulting in contrast-enhanced US/CT imaging and photothermal killing effect in vitro. Furthermore, the production of microbubbles can serve as the blasting agents to collaboratively enhance PTT efficacy after NIR irradiation. When intravenously injected into tumor-bearing mice, the MoS₂-PFH-PLLAs exhibit a dual-modal US/CT imaging-guided synergistically therapeutic efficacy under NIR irradiation, resulting in tumor ablation. These nanotherapeutic agents demonstrate good biocompatibility, highly contrast-enhanced US/CT imaging, and combinational enhanced PTT efficacy.

A Highly Efficient One-for-All Nanodroplet for Ultrasound Imaging-Guided and Cavitation-Enhanced Photothermal Therapy

BACKGROUND

Photothermal therapy (PTT) has attracted considerable attention for cancer treatment as it is highly controllable and minimally invasive. Various multifunctional nanosystems have been fabricated in an "all-in-one" form to guide and enhance PTT by integrating imaging and therapeutic functions. However, the complex fabrication of nanosystems and their high cost limit its clinical translation.

MATERIALS AND METHODS

Herein, a high efficient "one-for-all" nanodroplet with a simple composition but owning multiple capabilities was developed to achieve ultrasound (US) imaging-guided and cavitation-enhanced PTT. Perfluoropentane (PFP) nanodroplet with a polypyrrole (PPy) shell (PFP@PPy nanodroplet) was synthesized via ultrasonic emulsification and in situ oxidative polymerization. After characterization of the morphology, its photothermal effect, phase transition performance, as well as its capabilities of enhancing US imaging and acoustic cavitation were examined. Moreover, the antitumor efficacy of the combined therapy with PTT and acoustic cavitation via the PFP@PPy nanodroplets was studied both in vitro and in vivo.

RESULTS

The nanodroplets exhibited good stability, high biocompatibility, broad optical absorption over the visible and near-infrared (NIR) range, excellent photothermal conversion with an efficiency of 60.1% and activatable liquid-gas phase transition performance. Upon NIR laser and US irradiation, the phase transition of PFP cores into microbubbles significantly enhanced US imaging and acoustic cavitation both in vitro and in vivo. More importantly, the acoustic cavitation enhanced significantly the antitumor efficacy of PTT as compared to PTT alone thanks to the cavitation-mediated cell destruction, which demonstrated a substantial increase in cell detachment, 81.1% cell death in vitro and 99.5% tumor inhibition in vivo.

CONCLUSION

The PFP@PPy nanodroplet as a "one-for-all" theranostic agent achieved highly efficient US imaging-guided and cavitation-enhanced cancer therapy, and has considerable potential to provide cancer theranostics in the future.

Exploring the transition of polydopamine-shelled perfluorohexane emulsion droplets into microbubbles using small- and ultra-small-angle neutron scattering

Perfluorocarbon emulsion droplets are interesting colloidal systems with applications, ranging from diagnostics and theranostics to drug delivery, due to their controllable phase transition into microbubbles via heat application or acoustic droplet vapourisation. This work highlights the application of small- and ultra-small-angle neutron scattering (SANS and USANS, respectively), in combination with contrast variation techniques, in observing the in situ phase transition of polydopamine-stabilised perfluorohexane (PDA/PFH) emulsion droplets into microbubbles during heating. Results show peak USANS intensities at temperatures around 90 °C, which indicates that the phase transition of PDA/PFH emulsion droplets occurs at significantly higher temperatures than the bulk boiling point of pure liquid PFH (56 °C). Analysis and model fitting of the SANS and USANS data allowed us to estimate droplet sizes and interfacial properties at different temperatures (20 °C, 90 °C, and 20 °C after cooling), giving valuable insights about the transformation of these polydisperse emulsion droplet systems.

Phase-Transformation Nanoparticle-Mediated Sonodynamic Therapy: An Effective Modality to Enhance Anti-Tumor Immune Response by Inducing Immunogenic Cell Death in Breast Cancer

Purpose

Immunologically quiescent of breast cancer cells has been recognized as the key impediment for the breast cancer immunotherapy. In this study, we aimed to investigate the role of nanoparticle-mediated sonodynamic therapy (SDT) in promoting anti-tumor immune of breast cancer cells and its potential immune mechanisms.

Materials and Methods

The phase-transformation nanoparticles (LIP-PFH nanoparticles) were in-house prepared and its physiochemical characters were detected. The CCK-8 assay, apoptosis analysis and Balb/c tumor model establishment were used to explore the anti-tumor effect of LIP-PFH nanoparticles triggered by low-intensity focused ultrasound (LIFU) both in vitro and in vivo. Flow cytometry and immunohistochemistry of CD4⁺T, CD8⁺T, CD8⁺PD-1⁺T in blood, spleen and tumor tissue were performed to represent the change of immune response. Detection of immunogenic cell death (ICD) markers was examined to study the potential mechanisms.

Results

LIP-PFH nanoparticles triggered by LIFU could inhibit the proliferation and promote the apoptosis of 4T1 cells both in vitro and in vivo. CD4⁺T and CD8⁺T cell subsets were significantly increased in blood, spleen and tumor tissue, meanwhile CD8⁺PD-1⁺T cells were reduced, indicating enhancement of anti-tumor immune response of breast cancer cells in the nanoparticle-mediated SDT group. Detection of ICD markers (ATP, high-mobility group box B1, and calreticulin) and flow cytometric analysis of dendritic cell (DC) maturity further showed that the nanoparticle-mediated SDT can promote DC maturation to increase the proportion of cytotoxic T cells by inducing ICD of breast cancer cells.

Conclusion

The therapy of nanoparticles-mediated SDT can effectively enhance anti-tumor immune response of breast cancer.

Stimuli-responsive polydopamine-based smart materials

This review provides in-depth insight into the structural engineering of PDA-based materials to enhance their responsive feature and the use of them in construction of PDA-based stimuli-responsive smart materials.

Mussel-Inspired Polydopamine: The Bridge for Targeting Drug Delivery System and Synergistic Cancer Treatment

Polydopamine (PDA), a mussel-inspired molecule, has been recognized as attractive in cancer therapy due to a number of inherent advantages, such as good biocompatibility, outstanding drug-loading capacity, degradability, superior photothermal conversion efficiency, and low tissue toxicity. Furthermore, due to its strong adhesive property, PDA is able to functionalize various nanomaterials, facilitating the construction of a PDA-based multifunctional platform for targeted or synergistic therapy. Herein, recent PDA research, including targeted drug delivery, single-mode therapy, and diverse synergistic therapies against cancer, are summarized and discussed. For synergistic therapy, advanced developments are highlighted, such as photothermal/radiotherapy, chemo-/photothermal/gene therapy, photothermal/immune therapy, and photothermal/photodynamic/immune therapy. Finally, the challenges and promise of PDA for biomedical applications in the future are discussed.

Polydopamine-on-liposomes: stable nanoformulations, uniform coatings and superior antifouling performance

Polydopamine (PDA), a mussel-inspired synthetic polymer, affords biocompatible and antifouling coatings on a variety of surfaces. However, the traditional protocol of preparing PDA by polymerizing dopamine (DA) under basic conditions yields physically-unstable and non-uniform coatings that are prone to delamination and exhibit compromised antifouling performance in vivo. Here, we show that the high local pH in the vicinity of vesicular self-assemblies formed by a series of acetal-based cationic amphiphiles can be exploited to conveniently polymerise DA under physiological conditions in a gradual manner without requiring any external oxidant. Two of the four PDA-liposome nanoformulations viz. PDA-L1 and PDA-L2 turned out to be highly stable physically and resisted precipitation for more than a month while the other two formulations (PDA-L3 and PDA-L4) were less stable and formed visible precipitates with time. Further, the PDA-liposome formulations had significantly improved haemocompatibility compared to that of pristine liposomes. PDA-L1 formed highly uniform, nanostructured coatings on implants like catheter, cotton and bandages that did not delaminate even after a week of continuous incubation in simulated body fluid, or on exposure to pH change and presence of proteolytic enzymes. The PDA-L1 coated catheter implants resisted biofouling by both Gram-positive and Gram-negative bacteria in vitro and also had superior in vivo performance in mice vis-à-vis the implants coated with traditional base-polymerised PDA formulation (BP-PDA). Thus, these novel liposomal PDA nanoformulations significantly improve the practical utility of PDA-based coatings for antimicrobial applications.

Nanoelectrochemical biosensors for monitoring ROS in cancer cells

Compared with normal cells, cancer or tumor cells have a specific microenvironment and apparently possess a relatively large amount of ROS/RNS, and their overexpression is one of the important reasons for tumor development and deterioration. Therefore, monitoring the changes of intracellular ROS/RNS can improve the awareness of the clinical manifestations of the disease, which will be beneficial for the early diagnosis of cancer and improving treatment efficiency. Herein, in this study we have exploited and constructed a novel strategy based on the SiC@C nanowire electrode for intracellular electrochemical analysis to monitor ROS levels in cancer or tumor cells. Firstly, the SiC@C nanowire electrode was utilized to detect the intracellular ROS radical changes involved in the relevant biological processes of cancer cells where fluorescent zinc nanoclusters were biosynthesized in situ in target cancer cells by using the intracellular microenvironment and specificity of these cancer cells. By combining a confocal fluorescence microscopy study simultaneously, our observations illustrate that accompanied by the apparent change of the intracellular ROS, these in situ biosynthesized fluorescent nanoclusters gradually accumulate inside the cytosolic area with the increase of the reaction time. Moreover, it is evident that the size of the SiC@C nanoelectrodes can match the single cell dimensions, and its unique high spatial resolution provides the possibility of relevant intracellular molecular detection. These nanoelectrochemical biosensors can be adopted to quantitatively determine the change of the ROS content in target single cells in the relevant biological microenvironment or during the in situ biosynthesis process, and are also beneficial for understanding the related mechanism of some specific biological processes including the in situ synthesis at the single cell level.

Red fluorescent pyrazoline-BODIPY nanoparticles for ultrafast and long-term bioimaging

Fluorescence bioimaging is very significant in studying biological processes. Fluorescent nanoparticles (NPs) manufactured from aggregation-induced emission (AIE) materials, as promising candidates, have attracted more attention. However, it is still a challenge to explore suitable AIE NPs for bioimaging. Herein, we synthesized pyrazoline-BODIPY (PZL-BDP) with a donor and acceptor (D-A) structure by a condensation reaction, cultured its single crystal, and studied its twisted intramolecular charge transfer (TICT) and AIE effects. PZL-BDP could self-assemble to form red fluorescent nanoparticles (PZL-BDP NPs) which showed a good fluorescence quantum yield of 15.8% in water. PZL-BDP NPs with excellent stability and biocompatibility exhibited a large Stokes shift (Δλ = 111 nm) which resulted in the reduction of external interference and enhancement of the fluorescence contrast. Furthermore, these nanoparticles could be readily internalized by HeLa cells and they stain the cells in just five seconds, indicating an ultrafast bioimaging protocol. Moreover, long-term tracking fluorescence signals in vivo for about 12 days were obtained. The bright red fluorescence, ultrafast cell staining ability, and long-term in vivo tracking competence outline the great potential of rational design nanomaterials with AIE characteristics for monitoring biological processes.