Tunable Properties of Polydopamine Nanoparticles and Coated Surfaces

Therapeutic potential of Polydopamine-Coated selenium nanoparticles in Osteoarthritis treatment

Osteoarthritis (OA) affects millions globally, with its prevalence expected to rise due to an aging population. Selenium nanoparticles (SeNPs) have shown therapeutic potential, and polydopamine (PDA) coatings on nanoparticles offered additional benefits, including enhanced biocompatibility, antioxidant properties, and anti-inflammatory effects. However, while SeNPs and PDA have demonstrated efficacy in several disease models, their role in OA remains underexplored. This study aimed to evaluate the therapeutic effects of PDA-coated SeNPs in the treatment of OA. We developed PDA-coated SeNPs (PDA-SeNP) to improve Reactive Oxygen Species (ROS) control and evaluated their anti-inflammatory and cartilage-regenerative effects in both in vitro and in vivo models of OA. Transmission electron microscopy confirmed that the sizes of PDA-SeNPs was 203 ± 11 nm, with PDA coatings of approximately 12 ± 2 nm on the SeNPs. In vitro, treatment with PDA-SeNPs significantly enhanced the expression of cartilage-regeneration markers while reducing inflammatory marker levels in chondrocytes. For the in vivo analysis, OA was induced by injecting monoiodoacetate into the knee joints of rats. Four weeks after treatment with phosphate-buffered saline (PBS, n = 6), SeNPs (n = 6), or PDA-SeNPs (n = 6), the incapacitance test demonstrated improved weight-bearing capacity in the SeNP and PDA-SeNP groups compared to the PBS control. Gross morphological assessment and histological analysis revealed that PDA-SeNPs mitigated cartilage damage more effectively than SeNPs alone. These findings suggest that PDA-SeNPs promote cartilage repair, enhance extracellular matrix synthesis, and reduce knee pain in OA, establishing them as promising candidates for future OA treatment.

Magnetic nanosheets: from iron oxide nanocubes to polydopamine embedded 2D clusters and their multi-purpose properties

We here develop stable bidimensional magnetic nanoclusters (2D-MNCs) of iron oxide nanocubes (IONCs) arranged in thin nanosheets of closed-packed nanocubes. The assembly occurs by means of a two-step approach: in the first one, the ionic surfactant, sodium dodecyl sulfate (SDS), acts as a transient water transfer agent and as 2D clustering agent to induce formation of a monolayer of nanocubes arranged in thin nanosheets. Next, the addition of dopamine followed by solution basification, induces the in situ polymerization of dopamine with a tunable shell tickness depending on the dopamine amount, which helps to compact the clusters and ensures the long term water stability of the clusters. TEM, cryo-EM, and SAXS techniques helped to reveal structural features of the 2D-clusters. The pH-dependent degradation properties of polydopamine, enable to disassemble the clusters in acidic tumour microenviroment leading to a four-fold increase in the magnetic particle imaging signal and a concomitant increase of the magnetic heat losses of these clusters, makes them appealing in magnetic hyperthermia, while the shortening of T2 relaxation time suggests their use as contrast in magnetic resonance imaging. Finally, with crystal violet dye, used as drug molecule, the feasibility to release payloads pre-encapsulated with the polydopamine polymer shell has been also shown.

Selective and sensitive detection of dimethyl phthalate in water using ferromagnetic nanomaterial-based molecularly imprinted polymers and SERS

To overcome the complicated pretreatment, low selectivity and low sensitivity detection associated with the detection of dimethyl phthalate (DMP), this study synthesized ferromagnetic nanomaterials that coupled with surface enhanced Raman scattering (SERS) and molecular imprinting polymers (MIPs). The pretreatment process can be simplified by ferromagnetic nanomaterials, then Fe3O4@SiO2@Ag@MIPs selectively adsorbing DMP can be achieved, and SERS can be applied for DMP detection with high sensitivity. As a control, the non-imprinted polymers (NIPs) Fe3O4@SiO2@Ag@NIPs were synthesized. Adsorption experiments results showed that the saturation adsorption amounts of Fe3O4@SiO2@Ag@MIPs is 36.74 mg/g with 40 mg/L DMP and Fe3O4@SiO2@Ag@NIPs is 17.45 mg/g. For DMP, Fe3O4@SiO2@Ag@MIPs have a greater affinity. In addition, after seven adsorption-desorption cycles the Fe3O4@SiO2@Ag@MIPs are reusable with approximately a 9.8 % loss in adsorption capacity. With an 8.7 × 10-9 M detection limit, DMP detection was performed by SERS, which revealed that the Raman intensities of the associated characteristic peak were linearly proportional to the DMP concentrations. As a result, the recovery rate of the testing artificial water varied from 87.9 % to 117 %. These outcomes show that the suggested technique for finding DMP in actual water samples is practical.

Temperature-Responsive Hydrogel System Integrating Wound Temperature Monitoring and On-demand Drug Release for Sequentially Inflammatory Process Regulation of Wound Healing

Wound healing faces challenges like inflammation, infection, and limited monitoring capabilities, and traditional dressings often lack the ability to promote healing or provide real-time wound status updates. Early pro-inflammatory responses help clear pathogens and damaged tissue, while timely anti-inflammatory modulation aids tissue regeneration, making sequential inflammation regulation crucial. Additionally, wound temperature, a key infection biomarker, enables real-time monitoring for effective management. We propose a temperature-responsive hydrogel dressing capable of two-stage sequential drug release and wound temperature monitoring. The hydrogel, composed of poly(N-isopropylacrylamide) (PNIPAM) and dopamine/methacrylated-modified hyaluronic acid (HA-MA-DA), allows temperature-based drug release control, sequential regulating pro-inflammatory and anti-inflammatory stages in wound healing. Interleukin-8 (IL-8), a pro-inflammatory molecule, is encapsulated into hydrogel matrix and rapidly released to trigger the initial inflammatory response. Furthermore, photothermally responsive and erastin-loaded polydopamine@PNIPAM nanoparticles (E-PD NPs) are incorporated to release the anti-inflammatory drug erastin upon near-infrared light exposure, terminating inflammation through cytosolic burial, and thus achieve anti-inflammatory effects at the second stage of wound healing. Furthermore, a bluetooth module enables real-time wound temperature monitoring. Combining sequential drug release with temperature monitoring, our hydrogel dressing addresses significant gaps in current wound healing technologies and offers new insights into personalized therapeutic interventions.

New Composite Materials Based on PVA, PVP, CS, and PDA

In this work, new materials based on the blends of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), chitosan (CS), and polydopamine (PDA) have been prepared. Fourier Transform Infrared Spectra have been conducted to verify the presence of individual components in the composite materials. EDX elemental analysis showed a clear view of the element's presence in the composite materials, with the maximum values for carbon and oxygen. Atomic force microscopy (AFM) was used to observe the surface topography and measure the surface roughness. In the case of the individual polymers, CS presented the higher value of surface roughness (Rq = 3.92 nm and Ra = 3.02 nm), and surface roughness was found to be the lowest in the case of polyvinyl pyrrolidone (PVP), and it was with values (Rq = 2.34 nm and Ra = 0.95 nm). PVA films presented the surface roughness, which was with the value (Rq = 3.38 nm and Ra = 2.11 nm). In the case of composites, surface roughness was highest for the composite based on PVA, PVP, and CS, which presented the value (Rq = 11.91 nm and Ra = 8.71 nm). After the addition of polydopamine to the polymeric composite of PVA, PVP, and CS, a reduction in the surface roughness was observed (Rq = 7.49 nm and Ra = 5.15 nm). The surface roughness for composite materials was higher than that of the individual polymers. The addition of PDA to polymeric composite (PVA/PVP/CS) led to a decrease in Young's modulus. The elongation percentage of the polymeric films based on the PVA/PVP/CS/PDA blend was higher than that of the blend without PDA (9.80% vs. 5.68% for the polymeric composite PVA/PVP/CS). The surface of polymeric films was hydrophilic. The results from the MTT assay showed that all tested specimens are non-toxic, and it was manifested by a significant increase in the viability of L929 cells compared with control cells. However, additional studies are required to check the biocompatibility of tested samples.

NIR-Responsive Deployable and Self-Fitting 4D-Printed Bone Tissue Scaffold

The treatment of irregular-shaped and critical-sized bone defects poses a clinical challenge. Deployable, self-fitting tissue scaffolds that can be implanted by minimally invasive procedures are a promising solution. Toward this, we fabricated NIR-responsive and programmable polylactide-co-trimethylene carbonate (PLMC) scaffolds nanoengineered with polydopamine nanoparticles (PDA) by extrusion-based three-dimensional (3D) printing. The 3D-printed scaffolds demonstrated excellent (>99%), fast (under 30 s), and tunable shape recovery under NIR irradiation. PLMC-PDA composites demonstrated significantly higher osteogenic potential in vitro as revealed by the significantly enhanced alkaline phosphatase (ALP) secretion and mineral deposition in contrast to neat PLMC. Intraoperative deployability and in vivo bone regeneration ability of PLMC-PDA composites were demonstrated, using self-fitting scaffolds in critical-sized cranial bone defects in rabbits. The 3D-printed scaffolds were deformed into compact shapes that could self-fit into the defect shape intraoperatively under low power intensity (0.76 W cm-2) NIR. At 6 and 12 weeks postsurgical implantation, near-complete bone regeneration was observed in PLMC-PDA composites, unlike neat PLMC through microcomputed tomography (micro-CT) analysis. The potential clinical utility of the 3D-printed composites to secure complex defects was confirmed through self-fitting of the scaffolds into irregular defects in ex vivo models of rabbit tibia, mandible, and tooth models. Taken together, the composite scaffolds fabricated here offer an innovative strategy for minimally invasive deployment to fit irregular and complex tissue defects for bone tissue regeneration.

Wood Fiber-Based Triboelectric Material with High Filtration Efficiency and Antibacterial Properties and Its Respiratory Monitoring in Mask

Self-powered wearable electronic products have rapidly advanced in the fields of sensing and health monitoring, presenting greater challenges for triboelectric materials. The limited surface polarity and structural defects in wood fibers restrict their potential as substitutes for petroleum-based materials. This study used bagasse fiber as the raw material and explored various methods, including functionalizing cellulose nanofibrils (CNFs) with polydopamine (PDA), in situ embedding of silver particles, filtration, and freeze-drying. These methods aimed to enhance the triboelectric output, antibacterial properties, and filtration properties of lignocellulosic materials. The Ag/PDA/CNF-based triboelectric nanogenerator (TENG) demonstrated an open-circuit voltage of 211 V and a short-circuit current of 18.1 μA. An aerogel prepared by freeze-drying the Ag/PDA/CNF material, combined with a polyvinylidene fluoride nanofiber structure fabricated by electrospinning, constitutes the TENG unit. A self-powered respiratory detection mask was created using this combination, achieving a filtration efficiency of 94.23% for 0.3 μm particles and an antibacterial rate exceeding 99%. In addition, it effectively responded to respiratory frequency signals of slow breathing, normal breathing, and shortness of breath, with the output electrical signal correlating with the respiratory frequency. This study considerably contributes to advancing wood fiber-based triboelectric materials as alternatives to petroleum-derived materials in self-powered wearable electronic products for medical applications.

Environment-responsive dopamine nanoplatform for tumor synergistic therapy

Nanoparticle-based photothermal therapy (PTT) has emerged as a promising approach in tumor treatment due to its high selectivity and low invasiveness. However, the penetration of near-infrared light (NIR) is limited, leading it fails to induce damage to the deep-seated tumor cells within the tumor tissue. Additionally, inefficient uptake of photothermal nanoparticles by tumor cells results in suboptimal outcomes for PTT. In this study, we utilized the adhesive properties of photothermal material, polydopamine (PDA), which can successfully load the photosensitizer indocyanine green (ICG) and chemotherapeutic drug doxorubicin (DOX) to achieve photothermal and chemotherapy synergy treatment (PDA/DOX&ICG), aiming to compensate the defects of single tumor treatment. To extending the blood circulation time of PDA/DOX&ICG nanoparticles, evading clearance by the body immune system and achieving targeted delivery to tumor tissues, a protective envelopment was created using erythrocyte membranes modified with folate acid (FA-EM). After reaching the tumor tissue, the obtained FA-EM@PDA/DOX&ICG nanoparticles can specific bind with folate acid receptors on the surface of tumor cells, which can improve the uptake behavior of FA-EM@PDA/DOX&ICG nanoparticles by tumor cells, and leading to the release of loaded DOX and ICG in response to the unique tumor microenvironment. ICG, as a typical photosensitizer, significantly enhances the photothermal conversion performance of FA-EM@PDA/DOX&ICG nanoparticles, thus inducing tumor cells damage. In vitro and in vivo experimental results demonstrated that the coordinated NIR treatment with FA-EM@PDA/DOX&ICG not only effectively inhibits tumor growth, but also exhibits superior biocompatibility, effectively mitigating DOX-induced tissue damage.

Polydopamine-Based Nanoparticles for Synergistic Chemotherapy of Prostate Cancer

Introduction

Immune regulatory small molecule JQ1 can block its downstream effector PD-L1 pathway and effectively reverse the PD-L1 upregulation induced by doxorubicin (DOX). So the synergistic administration of chemotherapeutic drug DOX and JQ1 is expected to increase the sensitivity of tumors to immune checkpoint therapy and jointly enhance the body's own immunity, thus effectively killing tumor cells. Therefore, a drug delivery system loaded with DOX and JQ1 was devised in this study.

Methods

Polydopamine nanoparticles (PDA NPs) were synthesized through spontaneous polymerization. Under appropriate pH conditions, DOX and JQ1 were loaded onto the surface of PDA NPs, and the release of DOX and JQ1 were measured using UV-Vis or high performance liquid chromatography (HPLC). The mechanism of fabricated nanocomplex in vitro was investigated by cell uptake experiment, cell viability assays, apoptosis assays, and Western blot analysis. Finally, the tumor-bearing mouse model was used to evaluate the tumor-inhibiting efficacy and the biosafety in vivo.

Results

JQ1 and DOX were successfully loaded onto PDA NPs. PDA-DOX/JQ1 NPs inhibited the growth of prostate cancer cells, reduced the expression of apoptosis related proteins and induced apoptosis in vitro. The in vivo biodistribution indicated that PDA-DOX/JQ1 NPs could accumulated at the tumor sites through the EPR effect. In tumor-bearing mice, JQ1 delivered with PDA-DOX/JQ1 NPs reduced PD-L1 expression at tumor sites, generating significant tumor suppression. Furthermore, PDA-DOX/JQ1 NPs could reduce the side effects, and produce good synergistic treatment effect in vivo.

Conclusion

We have successfully prepared a multifunctional platform for synergistic prostate cancer therapy.

Thermal-Accelerated Urease-Driven Bowl-Like Polydopamine Nanorobot for Targeted Photothermal/Photodynamic Antibiotic-Free Antibacterial Therapy

The problem of antibiotic resistance seriously affects the treatment of bacterial infections, so there is an urgent need to develop novel antibiotic-independent antimicrobial strategies. Herein, a urease-driven bowl-like mesoporous polydopamine nanorobot (MPDA@ICG@Ur@Man) based on single-wavelength near-infrared (NIR) remote photothermal acceleration to achieve antibiotic-free phototherapy(photothermal therapy, PTT, plus photodynamic therapy, PDT) is first reported. The smart nanorobots can perform active movement by decomposing urea to produce carbon dioxide and ammonia. Particularly, the elevated local temperature during PTT can increase urease activity to enhance the autonomous movement and thus increase the contact between the antimicrobial substance and bacteria. Compared with a nanomotor propelled by urea only, the diffusion coefficient (De) of photothermal-accelerated nanorobots is increased from 1.10 to 1.26 µm2 s-1. More importantly, urease-driven bowl-like nanorobots with photothermal enhancement can specifically identify Escherichia coli (E. coli) and achieve simultaneous PTT/PDT at a single wavelength with 99% antibactericidal activity in vitro. In a word, the urease-driven bowl-like nanorobots guided by photothermal-accelerated strategy could provide a novel perspective for increasing PTT/PDT antibacterial therapeutic efficacy and be promising for various antibiotic-free sterilization applications.

pH-Mediated Mucus Penetration of Zwitterionic Polydopamine-Modified Silica Nanoparticles

Zwitterionic polymers have emerged as promising trans-mucus nanocarriers due to their superior antifouling properties. However, for pH-sensitive zwitterionic polymers, the effect of the pH microenvironment on their trans-mucus fate remains unclear. In this work, we prepared a library of zwitterionic polydopamine-modified silica nanoparticles (SiNPs-PDA) with an isoelectric point of 5.6. Multiple-particle tracking showed that diffusion of SiNPs-PDA in mucus with a pH value of 5.6 was 3 times faster than that in mucus with pH value 3.0 or 7.0. Biophysical analysis found that the trans-mucus behavior of SiNPs-PDA was mediated by hydrophobic and electrostatic interactions and hydrogen bonding between mucin and the particles. Furthermore, the particle distribution in the stomach, intestine, and lung demonstrated the pH-mediated mucus penetration behavior of the SiNPs-PDA. This study reveals the pH-mediated mucus penetration behavior of zwitterionic nanomaterials, which provides rational design strategies for zwitterionic polymers as nanocarriers in various mucus microenvironments.

Recent Progress of Photothermal Therapy Based on Conjugated Nanomaterials in Combating Microbial Infections

Photothermal therapy has the advantages of non-invasiveness, low toxicity, simple operation, a broad spectrum of antibacterial ability, and non-proneness to developing drug resistance, which provide it with irreplaceable superiority in fighting against microbial infection. The effect of photothermal therapy is closely related to the choice of photothermal agent. Conjugated nanomaterials are potential candidates for photothermal agents because of their easy modification, excellent photothermal conversion efficiency, good photostability, and biodegradability. In this paper, the application of photothermal agents based on conjugated nanomaterials in photothermal antimicrobial treatment is reviewed, including conjugated small molecules, conjugated oligomers, conjugated polymers, and pseudo-conjugated polymers. At the same time, the application of conjugated nanomaterials in the combination of photothermal therapy (PTT) and photodynamic therapy (PDT) is briefly introduced. Finally, the research status, limitations, and prospects of photothermal therapy using conjugated nanomaterials as photothermal agents are discussed.

Mussel-inspired dynamic facet-selective capping approach to highly uniform α-calcium sulfate hemihydrate crystals

We report herein a dynamic facet-selective capping (dFSC) strategy for α-calcium sulfate hemihydrate crystal growth from dihydrate gypsum in the presence of a catechol-derived PEI capping agent (DPA-PEI) with inspiration by the biomineralization process of mussel. The crystal shape is controllable and varies from long and pyramid-tipped prisms to thin hexagonal plate. The highly uniform truncated crystals have extremely high compression and bending strengths after hydration molding.