Polydopamine-based nanomaterials and their potentials in advanced drug delivery and therapy

Smart zwitterionic coatings with precise pH-responsive antibacterial functions for bone implants to combat bacterial infections

Hydrophilic antifouling coatings based on zwitterionic polymers have been widely applied for the surface modification of bone implants to combat biofilm formation and reduce the likelihood of implant-related infections. However, their long-term effectiveness is significantly limited by the lack of effective and precise antibacterial activity. Here, a pH-responsive smart zwitterionic antibacterial coating (PSB/GS coating) was designed and robustly fabricated onto titanium-base bone implants by using a facile two-step method. First, dopamine (DA) and a poly(sulfobetaine methacrylate-co-dopamine methacrylamide) (PSBDA) copolymer were deposited on implants via mussel-inspired surface chemistry, resulting in a hydrophilic base coating with abundant catechol residues. Next, an amino-rich antibiotic, gentamicin sulfate (GS), was covalently linked to the coating through the formation of acid-sensitive Schiff base bonds between the amine groups of GS and the catechol residues present in both the zwitterionic polymer and the DA component. During the initial implantation period, the hydrophilic zwitterionic polymers demonstrated the desired anti-fouling properties that could effectively reduce protein and bacterial adhesion by over 90%. With time, the bacterial proliferation led to a decrease in the microenvironment pH value, resulting in the hydrolysis of the acid-sensitive Schiff base bonds, thereby releasing GS on demand and effectively enhancing the anti-biofilm properties of coatings. Benefiting from this synergistic antifouling and smart antibacterial activities, the PSB/GS coating exerted an excellent anti-infective activity in both in vivo preoperative and postoperative infection rat models. This proposed facile yet effective coating strategy is expected to provide a promising solution to combat bone implant-related infections.

Melanin-Like Nanomedicine Functions as a Novel RPE Ferroptosis Inhibitor to Ameliorate Retinal Degeneration and Visual Impairment in Dry Age-Related Macular Degeneration

Ferrous ion accumulation and lethal oxidative stress mediate irreversible retinal pigment epithelial (RPE) cell ferroptosis and subsequent photoreceptor degeneration, a potential key pathogenic factor in the onset of dry age-related macular degeneration (dAMD), causing irreversible vision loss in the global elderly population. However, currently, no effective interventional treatment strategy exists in clinical practice. Herein, lesion site-targeted melanin-like nanoparticles, named ConA-MelNPs, are designed as a novel ferroptosis inhibitor for retinal degenerative diseases. ConA-MelNPs possessed chelating iron ion characteristics, alleviating severe mitochondrial damage caused by oxidative stress and protecting RPE cells from ferroptosis induced by sodium iodate (NaIO3). In a preclinical dAMD mouse model, a single intravitreal injection of ConA-MelNPs yielded significant responses in electroretinograms and visually-driven optomotor responses in visually impaired mice, resisting the challenge posed by secondary NaIO3-induced injuries, with the long-term sustainability of its therapeutic effect. Mechanistically, ConA-MelNPs achieve a therapeutic effect by interrupting the detrimental cascade involving "RPE cell ferroptosis, lethal oxidative stress, and microglial proinflammatory activation," affording the restoration of retinal homeostasis. The synthesized ConA-MelNPs demonstrated good biosafety, with no detected ophthalmic or systemic side effects. Collectively, ConA-MelNPs are proposed as a promising therapeutic option for atrophic retinal diseases such as dAMD.

Diselenide-Bridged Mesoporous Silica-Based Nanoplatform with a Triple ROS-Scavenging Effect for Intracerebral Hemorrhage Treatment

Oxidative stress (OS) is a major mediator of secondary brain injury following intracerebral hemorrhage (ICH). Thus, antioxidant therapy is emerging as an attractive strategy to combat ICH. To achieve both reactive oxygen species (ROS) scavenging ability and on-demand drug release ability, we constructed a novel polydopamine (PDA)-coated diselenide-bridged mesoporous silica nanoparticle (DSeMSN) drug delivery system (PDA-DSeMSN). Edaravone (Eda) was blocked in the pores of DSeMSN by covering the pores with PDA as a gatekeeper. The drug maintained nearly "zero release" before reaching the lesion site, while in the ROS-enriched circumstances, the PDA shell went through degradation and the doped diselenide bonds broke up, triggering the disintegration of nanoparticles and leading to Eda release. Interestingly, the ROS-degradable property of the PDA shell and diselenide bond endowed the system with enhanced ROS-eliminating capacity. The synergistic effect of ROS-responsive drug delivery and ROS-scavenging PDA-DSeMSN showed efficient antioxidative and mitochondria protective performance without apparent toxicity in vitro. Importantly, PDA-DSeMSN@Eda through intravenous administration specifically accumulated in perihematomal sites and demonstrated robust neuroprotection in an ICH mouse model through antioxidative and antiapoptotic effects with high biological safety. Thus, the PDA-DSeMSN platform holds tremendous potential as an excellent carrier for on-demand delivery of drugs and provides a new and effective strategy for the clinical treatment of ICH.

Mussel-inspired immunomodulatory and osteoinductive dual-functional hydroxyapatite nanoplatform for promoting bone regeneration

Simultaneously modulating the inflammatory microenvironment and promoting local bone regeneration is one of the main challenges in treating bone defects. In recent years, osteoimmunology has revealed that the immune system plays an essential regulatory role in bone regeneration and that macrophages are critical components. In this work, a mussel-inspired immunomodulatory and osteoinductive dual-functional hydroxyapatite nano platform (Gold/hydroxyapatite nanocomposites functionalized with polydopamine - PDA@Au-HA) is developed to accelerate bone tissues regeneration by regulating the immune microenvironment. PDA coating endows nanomaterials with the ability to scavenge reactive oxygen species (ROS) and anti-inflammatory properties, and it also exhibits an immunomodulatory ability to inhibit M1 macrophage polarization and activate M2 macrophage secretion of osteogenesis-related cytokines. Most importantly, this nano platform promotes the polarization of M2 macrophages and regulates the crosstalk between macrophages and pre-osteoblast cells to achieve bone regeneration. Au-HA can synergistically promote vascularized bone regeneration through sustained release of Ca and P particles and gold nanoparticles (NPs). This nano platform has a synergistic effect of good compatibility, scavenging of ROS, and anti-inflammatory and immunomodulatory capability to accelerate the bone repair process. Thus, our research offers a possible therapeutic approach by exploring PDA@Au-HA nanocomposites as a bifunctional platform for tissue regeneration.

Erythrocyte membrane coated with nitrogen-doped quantum dots and polydopamine composite nano-system combined with photothermal treatment of Alzheimer's disease

Mitochondrial dysfunction and metal ion imbalance are recognized as pathological hallmarks of Alzheimer's Disease (AD), leading to deposition of β-amyloid (Aβ) thereby and inducing neurotoxicity, activating apoptosis, eliciting oxidative stress, and ultimately leading to cognitive impairment. In this study, the red blood cell membrane (RBC) was used as a vehicle for encapsulating carbon quantum dots (CQD) and polydopamine (PDA), creating a nanocomposite (PDA-CQD/RBC). This nanocomposite was combined with near-infrared light (NIR) for AD treatment. The RBC offers anti-immunorecognition properties to evade immune clearance, PDA exhibits enzyme-mimicking activity to mitigate oxidative stress damage, and CQD acts as a chelating agent for metal ions (Cu2+), effectively preventing Cu2+-mediated aggregation of Aβ. Furthermore, the local heating induced by near-infrared laser irradiation can dismantle the formed Aβ fibers and enhance the blood-brain barrier's permeability. Both in vitro and animal experiments have shown that PDA-CQD/RBC, in combination with NIR, mitigates neuroinflammation, and ameliorates behavioral deficits in mice. This approach targets multiple pathological pathways, surpassing the limitations of single-target treatments and enhancing therapeutic efficacy while decelerating disease progression.

Mild hyperthermia enhanced synergistic uric acid degradation and multiple ROS elimination for an effective acute gout therapy

BACKGROUND

Acute gouty is caused by the excessive accumulation of Monosodium Urate (MSU) crystals within various parts of the body, which leads to a deterioration of the local microenvironment. This degradation is marked by elevated levels of uric acid (UA), increased reactive oxygen species (ROS) production, hypoxic conditions, an upsurge in pro-inflammatory mediators, and mitochondrial dysfunction.

RESULTS

In this study, we developed a multifunctional nanoparticle of polydopamine-platinum (PDA@Pt) to combat acute gout by leveraging mild hyperthermia to synergistically enhance UA degradation and anti-inflammatory effect. Herein, PDA acts as a foundational template that facilitates the growth of a Pt shell on the surface of its nanospheres, leading to the formation of the PDA@Pt nanomedicine. Within this therapeutic agent, the Pt nanoparticle catalyzes the decomposition of UA and actively breaks down endogenous hydrogen peroxide (H2O2) to produce O2, which helps to alleviate hypoxic conditions. Concurrently, the PDA component possesses exceptional capacity for ROS scavenging. Most significantly, Both PDA and Pt shell exhibit absorption in the Near-Infrared-II (NIR-II) region, which not only endow PDA@Pt with superior photothermal conversion efficiency for effective photothermal therapy (PTT) but also substantially enhances the nanomedicine's capacity for UA degradation, O2 production and ROS scavenging enzymatic activities. This photothermally-enhanced approach effectively facilitates the repair of mitochondrial damage and downregulates the NF-κB signaling pathway to inhibit the expression of pro-inflammatory cytokines.

CONCLUSIONS

The multifunctional nanomedicine PDA@Pt exhibits exceptional efficacy in UA reduction and anti-inflammatory effects, presenting a promising potential therapeutic strategy for the management of acute gout.

An antibacterial membrane based on Janus bacterial cellulose with nano-sized copper oxide through polydopamine conjugation for infectious wound healing

Bacterial cellulose (BC) produced by Acetobacter xylinum has great advantages in wound dressing. However, the structural limitation under static culture, and lack of antibacterial properties restrict its application, especially for infectious wound healing. The present study reported an original wound dressing, which was composed of a Janus BC membrane with antibacterial nano-sized copper oxide (CuO) through polydopamine (PDA) conjugation to promote wound healing under infectious condition. The finished product (CuO/PDA/BC membrane) exhibited favorable air permeability, high hydrophilicity and good mechanical properties, as well as strong antibacterial effects by the sustained release of CuO and photothermal effect of CuO/PDA. Furthermore, CuO/PDA/BC membrane inhibited inflammatory response and promoted wound healing in an infectious wound model in vivo. These results suggested that our CuO/PDA/BC membrane had great potential as wound dressing for infectious wound healing.

Multicomponent Pathogen-Mimicking Nanoparticles Induce Intestinal Immune Responses against Paratuberculosis

Given the worldwide problem posed by enteric pathogens, the discovery of safe and efficient intestinal adjuvants combined with novel antigen delivery techniques is essential to the design of mucosal vaccines. In this work, we designed poly (lactic-co-glycolic acid) (PLGA)-based nanoparticles (NPs) to codeliver all-trans retinoic acid (atRA), novel antigens, and CpG. To address the insolubility of the intestinal adjuvant atRA, we utilized PLGA to encapsulate atRA and form a "nanocapsid" with polydopamine. By leveraging polydopamine, we adsorbed the water-soluble antigens and the TLR9 agonist CpG onto the NPs' surface, resulting in the pathogen-mimicking PLPCa NPs. In this study, the novel fusion protein (HBf), consisting of the Mycobacterium avium subspecies paratuberculosis antigens HBHA, Ag85B, and Bfra, was coloaded onto the NPs. In vitro, PLPCa NPs were shown to promote the activation and maturation of bone marrow-derived dendritic cells. Additionally, we found that PLPCa NPs created an immune-rich microenvironment at the injection site following intramuscular administration. From the results, the PLPCa NPs induced strong IgA levels in the gut in addition to enhancing powerful systemic immune responses. Consequently, significant declines in the bacterial burden and inflammatory score were noted in PLPCa NPs-treated mice. In summary, PLPCa can serve as a novel and safe vaccine delivery platform against gut pathogens, such as paratuberculosis, capable of activating both systemic and intestinal immunity.

A Review for Uncovering the "Protein-Nanoparticle Alliance": Implications of the Protein Corona for Biomedical Applications

Understanding both the physicochemical and biological interactions of nanoparticles is mandatory for the biomedical application of nanomaterials. By binding proteins, nanoparticles acquire new surface identities in biological fluids, the protein corona. Various studies have revealed the dynamic structure and nano-bio interactions of the protein corona. The binding of proteins not only imparts new surface identities to nanoparticles in biological fluids but also significantly influences their bioactivity, stability, and targeting specificity. Interestingly, recent endeavors have been undertaken to harness the potential of the protein corona instead of evading its presence. Exploitation of this 'protein-nanoparticle alliance' has significant potential to change the field of nanomedicine. Here, we present a thorough examination of the latest research on protein corona, encompassing its formation, dynamics, recent developments, and diverse bioapplications. Furthermore, we also aim to explore the interactions at the nano-bio interface, paving the way for innovative strategies to advance the application potential of the protein corona. By addressing challenges and promises in controlling protein corona formation, this review provides insights into the evolving landscape of the 'protein-nanoparticle alliance' and highlights emerging.

Lysine-Polydopamine Nanocrystals Loaded with the Codrug Abemaciclib-Flurbiprofen for Oral Treatment of Cancer

Nonsteroidal anti-inflammatory drugs (NSAIDs) combined with chemotherapeutic agents for the treatment of colorectal cancer (CRC) are a promising therapeutic strategy. NSAIDs can effectively boost the antitumor efficacy of chemotherapeutic agents by inhibiting the synthesis of COX-2. However, hazardous side effects and barriers to oral drug absorption are the main challenges for combination therapy with chemotherapeutics and NSAIDs. To address these issues, a safe and effective lysine-polydopamine@abemaciclib-flurbiprofen (Flu) codrug nanocrystal (Lys-PDA@AF NCs) was designed. Abemaciclib (Abe), a novel and effective inhibitor of the CDK4/6 enzyme, and Flu were joined to prepare Abemaciclib-Flu codrug (AF) by amide bonds, and then the AF was made into nanocrystals. Lysine-modified polydopamine was selected as a shell to encapsulate nanocrystals to enhance intestinal adhesion and penetration and lengthen the duration time of drugs in vivo. Nuclear magnetic resonance, Fourier transform infrared, Massspectrometry, X-ray photoelectron spectroscopy, Transmission electron microscopy, and drug loading were used to evaluate the physicochemical characteristics of the nanocrystals. In our study, Abe and Flu were released to exert their synergistic effect when the amide bond of AF was broken and the amide bond was sensitive to cathepsin B which is overexpressed in most tumor tissues, thus increasing the selectivity of the drug to the tumor. The results showed that Lys-PDA@AF NCs had higher cytotoxicity for CRC cell with an IC50 of 4.86 μg/mL. Additionally, pharmacokinetics showed that Abe and Flu had similar absorption rates in the Lys-PDA@AF NCs group, improving the safety of combination therapy. Meanwhile, in vivo experiments showed that Lys-PDA@AF NCs had excellent antitumor effects and safety. Overall, it was anticipated that the created Lys-PDA@AF NCs would be a potential method for treating cancer.

A surface-independent bioglue using photo-crosslinkable benzophenone moiety

Surface coating technology is broadly demanded across various fields, including marine and biomedical materials; therefore, a facile and versatile approach is desired. This study proposed an attractive surface coating strategy using photo-crosslinkable benzophenone (BP) moiety for biomaterials application. BP-containing "bioglue" polymer can effectively crosslink with all kinds of surfaces and biomolecules. Upon exposure to ultraviolet (UV) light, free radical reaction from the BP glue facilitates the immobilization of diverse molecules onto different substrates in a straightforward and user-friendly manner. Through either one-step, mixing the bioglue with targeted biomolecules, or two-step methods, pre-coating the bioglue and then adding targeted biomolecules, polyacrylic acid (PAA), cyclic RGD-containing peptides, and proteins (gelatin, collagen, and fibronectin) were successfully immobilized on substrates. After drying the bioglue, targeted biomolecules can still be immobilized on the surfaces preserving their bioactivity. Cell culture on biomolecule-immobilized surfaces using NIH 3T3 fibroblasts and human bone marrow stem cells (hBMSCs) showed significant improvement of cell adhesion and activity compared to the unmodified control in serum-free media after 24 hours. Furthermore, hBMSCs on the fibronectin-immobilized surface showed an increased calcium deposition after 21 days of osteogenic differentiation, suggesting that the immobilized fibronectin is highly bioactive. Given the straightforward protocol and substrate-independent bioglue, the proposed coating strategy is promising in broad-range fields.

Melanin-like nanoparticles alleviate ischemia-reperfusion injury in the kidney by scavenging reactive oxygen species and inhibiting ferroptosis

Kidney transplantation is essential for patients with end-stage renal disease; however, ischemia-reperfusion injury (IRI) during transplantation can lead to acute kidney damage and compromise survival. Recent studies have reported that antiferroptotic agents may be a potential therapeutic strategy, by reducing production of reactive oxygen species (ROS). Therefore, we constructed rutin-loaded polydopamine nanoparticles (PEG-PDA@rutin NPs, referred to as PPR NPs) to eliminate ROS resulting from IRI. Physicochemical characterization showed that the PPR NPs were ∼100 nm spherical particles with good ROS scavenging ability. Notably, PPR NPs could effectively enter lipopolysaccharide (LPS)-treated renal tubular cells, then polydopamine (PDA) released rutin to eliminate ROS, repair mitochondria, and suppress ferroptosis. Furthermore, in vivo imaging revealed that PPR NPs efficiently accumulated in the kidneys after IRI and effectively protected against IRI damage. In conclusion, PPR NPs demonstrated an excellent ability to eliminate ROS, suppress ferroptosis, and protect kidneys from IRI.

Unveiling the molecular networks underlying cellular impairment in Saccharomyces cerevisiae: investigating the effects of magnesium oxide nanoparticles on cell wall integrity and endoplasmic reticulum stress response

Nanoparticles, particularly magnesium oxide nanoparticles (MgO-NPs), are increasingly utilized in various fields, yet their potential impact on cellular systems remains a topic of concern. This study aimed to comprehensively investigate the molecular mechanisms underlying MgO-NP-induced cellular impairment in Saccharomyces cerevisiae, with a focus on cell wall integrity, endoplasmic reticulum (ER) stress response, mitochondrial function, lipid metabolism, autophagy, and epigenetic alterations. MgO-NPs were synthesized through a chemical reduction method, characterized for morphology, size distribution, and elemental composition. Concentration-dependent toxicity assays were conducted to evaluate the inhibitory effect on yeast growth, accompanied by propidium iodide (PI) staining to assess membrane damage. Intracellular reactive oxygen species (ROS) accumulation was measured, and chitin synthesis, indicative of cell wall perturbation, was examined along with the expression of chitin synthesis genes. Mitochondrial function was assessed through Psd1 localization, and ER structure was analyzed using dsRed-HDEL marker. The unfolded protein response (UPR) pathway activation was monitored, and lipid droplet formation and autophagy induction were investigated. Results demonstrated a dose-dependent inhibition of yeast growth by MgO-NPs, with concomitant membrane damage and ROS accumulation. Cell wall perturbation was evidenced by increased chitin synthesis and upregulation of chitin synthesis genes. MgO-NPs impaired mitochondrial function, disrupted ER structure, and activated the UPR pathway. Lipid droplet formation and autophagy were induced, indicating cellular stress responses. Additionally, MgO-NPs exhibited differential cytotoxicity on histone mutant strains, implicating specific histone residues in cellular response to nanoparticle stress. Immunoblotting revealed alterations in histone posttranslational modifications, particularly enhanced methylation of H3K4me. This study provides comprehensive insights into the multifaceted effects of MgO-NPs on S. cerevisiae, elucidating key molecular pathways involved in nanoparticle-induced cellular impairment. Understanding these mechanisms is crucial for assessing nanoparticle toxicity and developing strategies for safer nanoparticle applications.

Polydopamine-Coated Polymer Nanofibers for In Situ Protein Loading and Controlled Release

Nanofibrous polymeric materials, combined with protein therapeutics, play a significant role in biomedical and pharmaceutical applications. However, the upload of proteins into nanofibers with a high yield and controlled release has been a challenging issue. Here, we report the in situ loading of a model protein (bovine serum albumin) into hydrophilic poly(vinyl alcohol) nanofibers via ice-templating, with a 100% protein drug loading efficiency. These protein-loaded nanofibers were further coated by polydopamine in order to improve the nanofiber stability and achieve a controlled protein release. The mass ratio between poly(vinyl alcohol) and bovine serum albumin influenced the percentage of proteins in composite nanofibers and fiber morphology. More particles and less nanofibers were formed with an increasing percentage of bovine serum albumin. By varying the coating conditions, it was possible to produce a uniform polydopamine coating with tunable thickness, which acted as an additional barrier to reduce burst release and achieve a more sustained release profile.

COVID-19 cooling: Nanostrategies targeting cytokine storm for controlling severe and critical symptoms

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants continue to wreak havoc worldwide, the "Cytokine Storm" (CS, also known as the inflammatory storm) or Cytokine Release Syndrome has reemerged in the public consciousness. CS is a significant contributor to the deterioration of infected individuals. Therefore, CS control is of great significance for the treatment of critically ill patients and the reduction of mortality rates. With the occurrence of variants, concerns regarding the efficacy of vaccines and antiviral drugs with a broad spectrum have grown. We should make an effort to modernize treatment strategies to address the challenges posed by mutations. Thus, in addition to the requirement for additional clinical data to monitor the long-term effects of vaccines and broad-spectrum antiviral drugs, we can use CS as an entry point and therapeutic target to alleviate the severity of the disease in patients. To effectively combat the mutation, new technologies for neutralizing or controlling CS must be developed. In recent years, nanotechnology has been widely applied in the biomedical field, opening up a plethora of opportunities for CS. Here, we put forward the view of cytokine storm as a therapeutic target can be used to treat critically ill patients by expounding the relationship between coronavirus disease 2019 (COVID-19) and CS and the mechanisms associated with CS. We pay special attention to the representative strategies of nanomaterials in current neutral and CS research, as well as their potential chemical design and principles. We hope that the nanostrategies described in this review provide attractive treatment options for severe and critical COVID-19 caused by CS.

Photothermal and Photocatalytic Glycol Chitosan and Polydopamine-Grafted Oxygen Vacancy Bismuth Oxyiodide (BiO1-x I) Nanoparticles for the Diagnosis and Targeted Therapy of Diabetic Wounds

Treatment of diabetic wounds is a significant clinical challenge due to the massive infections caused by bacteria. In this study, multifunctional glycol chitosan and polydopamine-coated BiO1-x I (GPBO) nanoparticles (NPs) with near-infrared (NIR) photothermal and photocatalytic abilities are prepared. When infection occurs, the local microenvironment becomes acidic, and the pH-switchable GPBO can target the bacteria of the wound site. The NIR-assisted GPBO treatment exhibits anti-bacterial effects with fast response, high efficiency, and long duration to Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. GPBO achieves excellent photothermal imaging and CT imaging of the mouse subcutaneous abscess model. With the assistance of NIR irradiation, the GPBO promotes the healing of the diabetic wound model with the effects of anti-bacteria, anti-inflammation, the M2 polarization promotion of macrophages, and angiogenesis. This is the first-time report of nano-sized BiO1-x I. The synthesis and selected application for the imaging and targeted therapy of diabetic wounds are presented. This study offers an example of the NP-assisted precise diagnosis and therapy of bacterial infection diseases.

Polydopamine Blending Increases Human Cell Proliferation in Gelatin-Xanthan Gum 3D-Printed Hydrogel

BACKGROUND

Gelatin-xanthan gum (Gel-Xnt) hydrogel has been previously modified to improve its printability; now, to increase its ability for use as cell-laden 3D scaffolds (bioink), polydopamine (PDA), a biocompatible, antibacterial, adhesive, and antioxidant mussel-inspired biopolymer, has been added (1-3% v/v) to hydrogel.

METHODS

Control (CT) and PDA-blended hydrogels were used to print 1 cm2 grids. The hydrogels' printability, moisture, swelling, hydrolysis, and porosity were tested after glutaraldehyde (GTA) crosslinking, while biocompatibility was tested using primary human-derived skin fibroblasts and spontaneously immortalized human keratinocytes (HaCaT). Keratinocyte or fibroblast suspension (100 µL, 2.5 × 105 cells) was combined with an uncrosslinked CT and PDA blended hydrogel to fabricate cylinders (0.5 cm high, 1 cm wide). These cylinders were then cross-linked and incubated for 1, 3, 7, 14, and 21 days. The presence of cells within various hydrogels was assessed using optical microscopy.

RESULTS AND DISCUSSION

PDA blending did not modify the hydrogel printability or physiochemical characteristics, suggesting that PDA did not interfere with GTA crosslinking. On the other hand, PDA presence strongly accelerated and increased both fibroblast and keratinocyte growth inside. This effect seemed to be linked to the adhesive abilities of PDA, which improve cell adhesion and, in turn, proliferation.

CONCLUSIONS

The simple PDA blending method described could help in obtaining a new bioink for the development of innovative 3D-printed wound dressings.

Polydopamine Nanosystems in Drug Delivery: Effect of Size, Morphology, and Surface Charge

Recently, drug delivery strategies based on nanomaterials have attracted a lot of interest in different kinds of therapies because of their superior properties. Polydopamine (PDA), one of the most interesting materials in nanomedicine because of its versatility and biocompatibility, has been widely investigated in the drug delivery field. It can be easily functionalized to favor processes like cellular uptake and blood circulation, and it can also induce drug release through two kinds of stimuli: NIR light irradiation and pH. In this review, we describe PDA nanomaterials' performance on drug delivery, based on their size, morphology, and surface charge. Indeed, these characteristics strongly influence the main mechanisms involved in a drug delivery system: blood circulation, cellular uptake, drug loading, and drug release. The understanding of the connections between PDA nanosystems' properties and these phenomena is pivotal to obtain a controlled design of new nanocarriers based on the specific drug delivery applications.

Heterogeneous Cu2O-SnO2 doped polydopamine fenton-like nanoenzymes for synergetic photothermal-chemodynamic antibacterial application

Wound infections caused by drug-resistant bacteria pose a great threat to human health, and the development of non-drug-resistant antibacterial approaches has become a research priority. In this study, we developed Cu2O-SnO2 doped polydopamine (CSPDA) triple cubic antibacterial nanoenzymes with high photothermal conversion efficiency and good Fenton-like catalase performance. CSPDA antibacterial nanoplatform can catalyze the generation of hydroxyl radical (·OH) from H2O2 at low concentration (50 μg∙mL-1) under 808 nm near-infrared (NIR) irradiation to achieve a combined photothermal therapy (PTT) and chemodynamic therapy (CDT). And the CSPDA antibacterial nanoplatform displays broad-spectrum and long-lasting antibacterial effects against both Gram-negative Escherichia coli (100 %) and Gram-positive Staphylococcus aureus (100 %) in vitro. Moreover, in a mouse wound model with mixed bacterial infection, the nanoplatform demonstrates a significant in vivo bactericidal effect while remaining good cytocompatible. To conclude, this study successfully develops an efficient and long-lasting bacterial infection treatment system. This system provided different options for future studies on the design of synergistic antimicrobial therapy. Hence, the as-synthesized synergetic photothermal therapy and chemodynamic therapy nanoenzymes have rapid and long-term bactericidal ability, well-conglutinant performance and effectively preventing wound infection for clinical application. STATEMENT OF SIGNIFICANCE: Wound infections caused by drug-resistant bacteria pose a great threat to human health, and the development of non-drug-resistant antibacterial approaches has become a research priority. In this study, we developed Cu2O-SnO2 doped polydopamine (CSPDA) triple cubic yolk-like antibacterial nanoenzymes with high photothermal conversion efficiency and Fenton-like catalase effect for photothermal and Chemodynamic antibacterial therapy, Meanwhile, the nanocomposites exhibit good antibioadhesion in a natural water environment for a long-time immersion. In conclusion, this study successfully develops an efficient and long-lasting bacterial infection treatment system. These findings present a pioneering strategy for future research on the design of synergistic antibacterial and antibioadhesive systems.

Photothermal antibacterial materials to promote wound healing

Wound healing is a crucial process that restores the integrity and function of the skin and other tissues after injury. However, external factors, such as infection and inflammation, can impair wound healing and cause severe tissue damage. Therefore, developing new drugs or methods to promote wound healing is of great significance. Photothermal therapy (PTT) is a promising technique that uses photothermal agents (PTAs) to convert near-infrared radiation into heat, which can eliminate bacteria and stimulate tissue regeneration. PTT has the advantages of high efficiency, controllability, and low drug resistance. Hence, nanomaterial-based PTT and its related strategies have been widely explored for wound healing applications. However, a comprehensive review of PTT-related strategies for wound healing is still lacking. In this review, we introduce the physiological mechanisms and influencing factors of wound healing, and summarize the types of PTAs commonly used for wound healing. Then, we discuss the strategies for designing nanocomposites for multimodal combination treatment of wounds. Moreover, we review methods to improve the therapeutic efficacy of PTT for wound healing, such as selecting the appropriate wound dressing form, controlling drug release, and changing the infrared irradiation window. Finally, we address the challenges of PTT in wound healing and suggest future directions.

Recent Advances in Biomimetic Nanocarrier-Based Photothermal Therapy for Cancer Treatment

Nanomedicine presents innovative solutions for cancer treatment, including photothermal therapy (PTT). PTT centers on the design of photoactivatable nanoparticles capable of absorbing non-toxic near-infrared light, generating heat within target cells to induce cell death. The successful transition from benchside to bedside application of PTT critically depends on the core properties of nanoparticles responsible for converting light into heat and the surface properties for precise cell-specific targeting. Precisely targeting the intended cells remains a primary challenge in PTT. In recent years, a groundbreaking approach has emerged to address this challenge by functionalizing nanocarriers and enhancing cell targeting. This strategy involves the creation of biomimetic nanoparticles that combine desired biocompatibility properties with the immune evasion mechanisms of natural materials. This review comprehensively outlines various strategies for designing biomimetic photoactivatable nanocarriers for PTT, with a primary focus on its application in cancer therapy. Additionally, we shed light on the hurdles involved in translating PTT from research to clinical practice, along with an overview of current clinical applications.

Tracking intracellular nuclear targeted-chemotherapy of chidamide-loaded Prussian blue nanocarriers by SERS mapping

The novel histone deacetylase drug chidamide (CHI) has been proven to regulate gene expression associated with oncogenesis via epigenetic mechanisms. However, huge side effects such as non-targeting, poor intracellular accumulation and low nuclear entry efficiency severely restrict its therapeutic efficacy. Dual-targeted nanodrug delivery systems have been proposed as the solution. Herein, we developed a CHI-loaded drug delivery nanosystem based on Prussian blue (PB) nanocarrier, which combines surface-enhanced Raman scattering (SERS) tracking function with cancer cell/nuclear-targeted chemotherapy capability. With the property of background-free SERS mapping, PB nanocarriers can serve as tracking agents to localize intracellular CHI. The incorporation of targeted molecules specifically enhances the cancer cell/nuclear internalization and chemotherapeutic effects of CHI-loaded PB nanocarriers. In vitro cytotoxicity assay clearly shows that the constructed CHI-loaded PB nanocarriers have significant inhibitory on Jurkat cell proliferation. Furthermore, SERS spectral analysis of Jurkat cells incubated with the CHI-loaded PB nanocarriers reveals obvious features of cellular apoptosis: DNA skeleton fragmentation, chromatin depolymerization, histone acetylation, and nucleosome conformation change. Importantly, this CHI-loaded PB nanocarrier will provide a new insight for lymphoblastic leukemia targeted chemotherapy.

Near-Infrared Light-Mediated Cyclodextrin Metal-Organic Frameworks for Synergistic Antibacterial and Anti-Biofilm Therapies

Bacterial infections pose a significant threat to global public health; therefore, the development of novel therapeutics is urgently needed. Herein, a controllable antibacterial nanoplatform utilizing cyclodextrin metal-organic frameworks (CD-MOFs) as a template to synthesize ultrafine silver nanoparticles (Ag NPs) in their porous structure is constructed. Subsequently, polydopamine (PDA) is encapsulated on the CD-MOFs' surface via dopamine polymerization to enhance the water stability and enable hyperthermia capacity. The resulting Ag@MOF@PDA generates localized hyperthermia and gradually releases Ag+ to achieve long-term photothermal-chemical bactericidal capability. The release rate of Ag+ can be accelerated by NIR-mediated heating in a controllable manner, quickly reaching the effective concentration and reducing the frequency of medication to avoid potential toxicity. In vitro experiments demonstrate that the combined antibacterial strategy can not only effectively kill both gram-negative and gram-positive bacteria, but also directly eradicate mature biofilms. In vivo results confirm that both bacterial- and biofilm-infected wounds treated with a combination of Ag@MOF@PDA and laser exhibit satisfactory recovery with minimal toxicity, displaying a superior therapeutic effect compared to other groups. Together, the results warrant that the Ag@MOF@PDA realizes synergistic antibacterial capacity and controllable release of Ag+ to combat bacterial and biofilm infections, providing a potential antibiotic-free alternative in the "post-antibiotic era."

Hollow-polydopamine-nanocarrier-based near-infrared-light/pH-responsive drug delivery system for diffuse alveolar hemorrhage treatment

Introduction: Diffuse alveolar hemorrhage (DAH) is a serious complication caused by systemic lupus erythematosus (SLE). Tissue damage and changes in immune response are all associated with excessive free radical production. Therefore, removing excess reactive oxygen species are considered a feasible scheme for diffuse alveolar hemorrhage treatment. Cyclophosphamide is often used as the main therapeutic drug in clinics. However, CTX carries a high risk of dose-increasing toxicity, treatment intolerance, and high recurrence rate. The combination of therapeutic drugs and functional nanocarriers may provide an effective solution. PDA is rich in phenolic groups, which can remove the reactive oxygen species generated in inflammatory reactions, and can serve as excellent free radical scavengers. Methods: We developed a hollow polydopamine (HPDA) nanocarrier loaded with CTX by ionization to prepare the novel nanoplatform, CTX@HPDA, for DAH treatment. The monodisperse silica nanoparticles were acquired by reference to the typical Stober method. PDA was coated on the surface of SiO₂ by oxidation self-polymerization method to obtain SiO₂@PDA NPs. Then, HPDA NPs were obtained by HF etching. Then HPDA was loaded with CTX by ionization to prepare CTX@HPDA. Then we tested the photothermal effect, animal model therapeutics effect, and biosafety of CTX@HPDA. Results: Material tests showed that the CTX@ HPDA nanoplatform had a uniform diameter and could release CTX in acidic environments. The vitro experiments demonstrated that CTX@HPDA has good photothermal conversion ability and photothermal stability. Animal experiments demonstrated that the CTX@HPDA nanoplatform had good biocompatibility. The nanoplatform can dissociate in acidic SLE environment and trigger CTX release through photothermal conversion. Combining HPDA, which scavenges oxygen free radicals, and CTX, which has immunosuppressive effect, can treat pulmonary hemorrhage in SLE. Micro-CT can be used to continuously analyze DAH severity and lung changes in mice after treatment. The pulmonary exudation in the various treatment groups improved to varying degrees. Discussion: In this study, we report a photothermal/PH-triggered nanocarrier (CTX@HPDA) for the precise treatment of SLE-DAH. CTX@HPDA is a simple and efficient nanocarrier system for DAH therapy. This work provides valuable insights into SLE treatment.

Investigation of Antimicrobial Effects of Polydopamine-Based Composite Coatings

Herein, polydopamine (PDA)-based antimicrobial coatings loaded with silver nanoparticles (Ag NPs) and gentamicin were designed and prepared on glass slides using two different approaches. To our knowledge, this study was performed for the first time with the aim to compare these methods (viz., in situ loading and physical adsorption method) regarding the loading and release behavior of payloads. In one method, gentamicin was in situ loaded on PDA-coated substrates during PDA polymerization followed by Ag NPs immobilization (named as Ag@Gen/PDA); for the second method, Ag NPs and gentamicin were simultaneously loaded onto PDA via physical adsorption by immersing pre-formed PDA coatings into a mixed solution of Ag NPs and gentamicin (named as Ag/Gen@PDA). The loading and release characteristics of these antimicrobial coatings were compared, and both gave variable outcomes. The in situ loading method consequently provided a relatively slow release of loaded antimicrobials, i.e., approx. 46% for Ag@Gen/PDA as compared to 92% from physically adsorbed Ag/GenPDA in an immersion period of 30 days. A similar trend was observed for gentamicin release, i.e., ~0.006 µg/mL from Ag@Gen/PDA and 0.02 µg/mL from Ag/Gen@PDA each day. The slower antimicrobial release from Ag@Gen/PDA coatings would ultimately provide an effective long-term antimicrobial property as compared to Ag/Gen@PDA. Finally, the synergistic antimicrobial activities of these composite coatings were assessed against two microbial species, namely, Staphylococcus aureus and Escherichia coli, hence providing evidence in the prevention of bacterial colonization.

Ultrasound-Targeted Microbubble Destruction-Mediated Cell-Mimetic Nanodrugs for Treating Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease that mainly affects joints, and it can lead to disability and damage to vital organs if not diagnosed and treated in time. However, all current therapeutic agents for RA have limitations such as high dose, severe side effects, long-term use, and unsatisfactory therapeutic effects. The long-term use and dose escalation of methotrexate (MTX) may cause mild and severe side effects. To overcome the limitations, it is critical to target drug delivery to the inflamed joints. In this work, we constructed a folic acid-targeted and cell-mimetic nanodrug, MTX-loaded mesoporous silica composite nanoplatform (MMPRF), which can regulate drug release under ultrasound (US) and microbubble (MB) mediation. The targeted delivery and drug therapy were investigated through in vitro RAW264.7 cell experiments and in vivo collagen-induced arthritis animal experiments. The result showed that the targeting ability to the joints of MMPRF was strong and was more significant after US and MB mediation, which can potently reduce joint swelling, bone erosion, and inflammation in joints. This work indicated that the US- and MB-mediated MMPRF not only would be a promising method for synergistic targeted treatment of RA but also may show high potential for serving as a nanomedicine for many other biomedical fields.

Role of nano-hydrogels coated exosomes in bone tissue repair

With the development of nanotechnology, nanomaterials are widely applied in different areas. Some nanomaterials are designed to be biocompatible and can be used in the medical field, playing an important role in disease treatment. Exosomes are nanoscale vesicles with a diameter of 30-200 nm. Studies have shown that exosomes have the effect of angiogenesis, tissue (skin, tendon, cartilage, et al.) repair and reconstruction. Nano-hydrogels are hydrogels with a diameter of 200 nm or less and can be used as the carrier to transport the exosomes into the body. Some orthopedic diseases, such as bone defects and bone infections, are difficult to handle. The emergence of nano-hydrogels coated exosomes may provide a new idea to solve these problems, improving the prognosis of patients. This review summarizes the function of nano-hydrogels coated exosomes in bone tissue repair, intending to illustrate the potential use and application of nano-hydrogels coated exosomes in bone disease.

Sialic acid-targeting multi-functionalized silicon quantum dots for synergistic photodynamic and photothermal cancer therapy

To explore the potential of silicon quantum dots (SiQDs) in combined photodynamic therapy (PDT) and photothermal therapy (PTT), we engineered the surface of SiQDs with the photosensitizer Ce6 and the tumor-cell-targeting ligand phenylboronic acid (PBA) via polydopamine-mediated chemistry. Upon irradiation with light of specific wavelengths, SiQDs@Ce6/PBA could generate high levels of reactive oxygen species (ROS) and trigger effective photo-to-thermal conversion. PBA-conjugation could not only increase the cellular uptake and transcellular transport capability of nanoparticles, but also enhance their tumor accumulation. In the presence of a 635 nm laser, SiQDs@Ce6/PBA was able to trigger intracellular ROS production, which further altered the mitochondrial membrane potential and promoted apoptosis of tumor cells. Finally, combined PDT/PTT treatments led to synergistically enhanced cancer cell killing and tumor-growth inhibition effects. This study demonstrates the surface engineering of silicon quantum dots for synergistic PDT/PTT cancer therapy.

Fabrication of Poly Dopamine@poly (Lactic Acid-Co-Glycolic Acid) Nanohybrids for Cancer Therapy via a Triple Collaboration Strategy

Breast cancer is a common malignant tumor among women and has a higher risk of early recurrence, distant metastasis, and poor prognosis. Systemic chemotherapy is still the most widely used treatment for patients with breast cancer. However, unavoidable side effects and acquired resistance severely limit the efficacy of treatment. The multi-drug combination strategy has been identified as an effective tumor therapy pattern. In this investigation, we demonstrated a triple collaboration strategy of incorporating the chemotherapeutic drug doxorubicin (DOX) and anti-angiogenesis agent combretastatin A4 (CA4) into poly(lactic-co-glycolic acid) (PLGA)-based co-delivery nanohybrids (PLGA/DC NPs) via an improved double emulsion technology, and then a polydopamine (PDA) was modified on the PLGA/DC NPs' surface through the self-assembly method for photothermal therapy. In the drug-loaded PDA co-delivery nanohybrids (PDA@PLGA/DC NPs), DOX and CA4 synergistically induced tumor cell apoptosis by interfering with DNA replication and inhibiting tumor angiogenesis, respectively. The controlled release of DOX and CA4-loaded PDA@PLGA NPs in the tumor region was pH dependent and triggered by the hyperthermia generated via laser irradiation. Both in vitro and in vivo studies demonstrated that PDA@PLGA/DC NPs enhanced cytotoxicity under laser irradiation, and combined therapeutic effects were obtained when DOX, CA4, and PDA were integrated into a single nanoplatform. Taken together, the present study demonstrates a nanoplatform for combined DOX, CA4, and photothermal therapy, providing a potentially promising strategy for the synergistic treatment of breast cancer.

An inorganic-organic-polymeric nanovehicle for targeting delivery of doxorubicin: Rational assembly, pH-stimulus release, and dual hyperthermia/chemotherapy of hepatocellular carcinoma

Efficiently synergistic therapy of hepatocellular carcinoma (HCC) by chemotherapeutic drug and photothermal agent remains a considerable challenge. Here, we report a nanodrug that integrates specific hepatoma-targeted delivery, pH-triggered drug release, and cooperative photothermal-chemotherapy function. By grafting the easily self-assembled CuS@polydopamine (CuS@PDA) nanocapsulation with polyacrylic acid (PAA), an inorganic-organic-polymeric hybrid nanovehicle was developed as a dual photothermal agent and carrier for loading antitumor drug-doxorubicin (DOX) through electrostatic adsorption and chemical linking antibody against GPC3 commonly overexpressed in HCC, resulting in the nanodrug, CuS@PDA/PAA/DOX/GPC3. The multifunctional nanovehicle had excellent biocompatibility, stability, and high photothermal conversion efficiency, due to the rationally designed binary CuS@PDA photothermal agent. The 72-h accumulative drug release in pH 5.5 tumor microenvironment can reach up to 84%, far higher than 15% measured in pH 7.4 condition. Notably, in contrast to the merely 20% survival rate of H9c2 and HL-7702 cells exposed to free DOX, their viabilities in the nanodrug circumstance can maintain 54% and 66%, respectively, suggesting the abated toxicity to the normal cell lines. When exposed to the hepatoma-targeting nanodrug, the viability of HepG2 cells was found to be 36%, which further drastically declined to 10% plus 808-nm NIR irradiation. Moreover, the nanodrug is potent to cause tumor ablation in HCC-modeled mice, and the therapeutic efficacy can be greatly enhanced under NIR stimulus. Histology analyses reveal that the nanodrug can effectively alleviate the chemical damage to heart and liver, as compared to free DOX. This work thus offers a facile strategy for design of targeting anti-HCC nanodrug toward combined photothermal-chemotherapy.

Nonporous versus Mesoporous Bioinspired Polydopamine Nanoparticles for Skin Drug Delivery

The use of polydopamine-based bioinspired nanomaterials has shed new light on advanced drug delivery arising from their efficient surface functionalization. More recently, the polydopamine self-assemblies formed in two different modalities, i.e., nonporous and mesoporous nanoparticles, have begun to attract attention due to their expedient and versatile properties. However, their possibility for use in dermal drug delivery for local therapy, as well as their interaction with the skin, has not yet been demonstrated. Our study aimed to compare and explore the feasibility of the self-assembled nonporous polydopamine nanoparticles (PDA) and mesoporous polydopamine nanoparticles (mPDA) for local skin drug delivery. The formation of the PDA and mPDA structures was confirmed by the UV-vis-NIR absorption spectrum, the Fourier transform infrared spectroscopy, and the nitrogen adsorption/desorption isotherms. Using retinoic acid (RA) as the model drug, their effects on drug loading, release, photostability, skin penetration, and radical scavenging were investigated. Laser scanning confocal microscopy (LSCM) and hematoxylin and eosin (H&E) were introduced to probe their delivery routes and possible interaction with the skin. The results indicated that both PDA and mPDA could reduce the photodegradation of RA, and mPDA showed significantly better radical scavenging activity and drug loading capacity. The ex vivo permeation study revealed that both PDA and mPDA significantly enhanced the delivery of RA into the deep skin layers by comparison with the RA solution, in which follicular and intercellular pathways existed, and alteration in the structure of stratum corneum was observed. In light of drug loading capacity, size controllability, physical stability, as well as radical scavenging activity, mPDA was more preferable due to the improvement of these factors. This work demonstrated the feasibility and promising application of PDA and mPDA nanoparticles for dermal drug delivery, and the comparative concept of these two types of biomaterials can provide implications for their use in other fields.

Polydopamine-Based Material and Their Potential in Head and Neck Cancer Therapy-Current State of Knowledge

Head and neck cancers (HNC) are among the most common cancers in the world. In terms of frequency of occurrence in the world, HNC ranks sixth. However, the problem of modern oncology is the low specificity of the therapies used, which is why most of the currently used chemotherapeutic agents have a systemic effect. The use of nanomaterials could overcome the limitations of traditional therapies. Researchers are increasingly using polydopamine (PDA) in nanotherapeutic systems for HNC due to its unique properties. PDA has found applications in chemotherapy, photothermal therapy, targeted therapy, and combination therapies that facilitate better carrier control for the effective reduction of cancer cells than individual therapies. The purpose of this review was to present the current knowledge on the potential use of polydopamine in head and neck cancer research.

Multi-applications of carbon dots and polydopamine-coated carbon dots for Fe3+ detection, bioimaging, dopamine assay and photothermal therapy

Carbon dots (CDs) or CDs/polymer composites have been applied in numerous fields. Here, novel CDs were synthesized by carbonization of egg yolk, and characterized by TEM, FTIR, XPS and photoluminescence spectra. The CDs were found to be approximate sphere in shape with an average size of 4.46 ± 1.17 nm, and emitted bright blue photoluminescence under UV irradiation. The photoluminescence of CDs was found selectively quenched by Fe³⁺ in a linear manner in the range of 0.05-0.45 mM, meaning they could be applied for Fe³⁺ detection in solution. Moreover, the CDs could be uptaken by HepG2 cells to exhibit bright blue photoluminescence. The intensity could reflect the level of intracellular Fe³⁺, indicating they could be further used for cell imaging and intracellular Fe³⁺ monitoring. Next, dopamine was polymerized on the surface of CDs to obtain the polydopamine (PDA)-coated CDs (CDs@PDA). We found PDA coating could quench the photoluminescence of CDs via inner filter effect, and the degree of quenching was linearly related to the logarithm of DA concentration (Log C_DA). Also, the selectivity experiment indicated the method had a high selectivity for DA over a number of possible interfering species. This indicated the CDs in combination with Tris buffer could be potentially applied as the assay kit of dopamine. At last, the CDs@PDA exhibited excellent photothermal conversion capability, and they could efficiently kill HepG2 cells under NIR laser irradiation. Overall, the CDs and CDs@PDA in this work exhibited many excellent advantages, and could be potentially used for multi-applications, such as Fe³⁺ sensor in solution and cellular, cell imaging, dopamine assay kit, as well as photothermal agents for cancer therapy.

Regulation of protein corona on liposomes using albumin-binding peptide for targeted tumor therapy

Nanocarriers entering the body are usually coated by plasma protein, leading to a protein "corona" easily recognized by tissues and cells. Adjusting the composition of protein coronas may be an efficient way to change the properties and behavior of nanoparticles in vivo. In this study, we modified doxorubicin-loaded liposomes (Lip/DOX) with an albumin-binding domain (ABD) to prepare nanoparticles (ABD-Lip/DOX) that can specifically bind to albumin and form albumin-based protein coronas in vivo for targeted tumor therapy. The prepared liposomes were spherical with a particle size of about 100 nm. After incubating the liposomes with rat serum, the albumin content was eight times higher on ABD-Lip than on control liposomes. ABD-Lip significantly inhibited adsorption of IgG and complement activation in rat serum in vitro, while corona-coated ABD-Lip was internalized to a significantly greater extent than corona-coated control liposomes. In addition, ABD-Lip showed longer blood circulation time, higher tumor accumulation and greater antitumor efficacy than control liposomes in mice bearing 4 T1 tumors, while both liposome formulations showed similar biocompatibility. These results confirm that adjusting the component of protein coronas around nanoparticles can improve their therapeutic efficacy.

Multifunctional and multimodality theranostic nanomedicine for enhanced phototherapy

Photodynamic therapy (PDT) has attracted much attention in recent years for its favorable therapeutic efficacy in cancer therapy. However, PDT alone is insufficient to improve the therapeutic efficiency mainly due to the limited penetration depth of light, the insufficient O₂ supply in the hypoxic microenvironment, and the high level of reducing substances in cancer cells. To overcome these limitations, a multifunctional MnO₂ nanoparticle was constructed with honeycomb MnO₂ which was loaded with the photosensitizer Ce6 and modified with polydopamine on its surface (HMnO₂/C&P) to achieve efficient PDT/mild photothermal treatment (PTT) combination therapy. HMnO₂/C&P had high drug loading contents (11.2% Ce6) and can be responsive to the tumor microenvironment (TME), supply O₂ to alleviate the hypoxic microenvironment, and clear GSH to reduce the consumption of ROS, thus enhancing the PDT effect. The introduction of PDA can improve the stability of HMnO₂/C&P, and further give the ability of PTT to act as nanomedicine. The results of in vitro and in vivo experiments show that HMnO₂/C&P based PDT/mild PTT combination therapy has an excellent inhibitory effect on tumor growth. Meanwhile, HMnO₂/C&P can act as a fluorescence imaging reagent and a TME triggerable magnetic resonance imaging (MRI) contrast agent, thus having excellent multimodal self-tracking abilities. Collectively, this study provides a new perspective on the design of multifunctional theranostic nanomedicine to maximize the efficacy of cancer phototherapy.

Study on combination therapy for lung cancer through pemetrexed-loaded mesoporous polydopamine nanoparticles

Lung cancer is one of the most commonly diagnosed cancers, and surgical resection is the optimal choice for the primary lung tumor. But for the secondary lung cancer, chemotherapy and combined radiotherapy still are the main strategies. To realize the combined treatment for non-small cell lung cancer (NSCLC), in this work, a nanoplatform based on pemetrexed (PE)-loaded mesoporous polydopamine (MPDA) nanoparticles were investigated. PE, a special therapeutic drug for NSCLC, was loaded into the MPDA nanoparticles via electrostatic attraction and was encapsulated with polyvinyl pyrrolidone (PVP). The results showed that, when irradiating with 808 nm near-infrared light, the PE loaded MPDA (MPDA@PE@PVP) nanoparticles have excellent photothermal conversion properties, which would result in increase of ambient temperature and could accelerate the release of PE. In vitro cell experiments proved that MPDA@PE@PVP nanoparticles have excellent killing ability for NSCLC A549 cells by the functions of PE and photothermal ability of MPDA nanoparticles. Meanwhile, the intra-cellular reactive oxygen species (ROS) levels of A549 cells in the MPDA@PE@PVP nanoparticle-treated group could be promoted significantly after irradiation, leading to the death of A549 cells. In vivo animal model results showed that MPDA@PE@PVP nanoparticles could gather at the tumor site by enhanced permeability and retention (EPR) effect and have significant inhibition ability for lung tumor by synergistic therapy of chemotherapy, photothermal therapy and photodynamic therapy.

Photoresponsive polymeric microneedles: An innovative way to monitor and treat diseases

Microneedles (MN) technology is an emerging technology for the transdermal delivery of therapeutics. When combined with photoresponsive (PR) materials, MNs can deliver therapeutics precisely and effectively with enhanced efficacy or synergistic effects. This review systematically summarizes the therapeutic applications of PRMNs in cancer therapy, wound healing, diabetes treatment, and diagnostics. Different PR approaches to activate and control the release of therapeutic agents from MNs are also discussed. Overall, PRMNs are a powerful tool for stimuli-responsive controlled-release therapeutic delivery to treat various diseases.

Progress in bioactive surface coatings on biodegradable Mg alloys: A critical review towards clinical translation

Mg and its alloys evince strong candidature for biodegradable bone implants, cardiovascular stents, and wound closing devices. However, their rapid degradation rate causes premature implant failure, constraining clinical applications. Bio-functional surface coatings have emerged as the most competent strategy to fulfill the diverse clinical requirements, besides yielding effective corrosion resistance. This article reviews the progress of biodegradable and advanced surface coatings on Mg alloys investigated in recent years, aiming to build up a comprehensive knowledge framework of coating techniques, processing parameters, performance measures in terms of corrosion resistance, adhesion strength, and biocompatibility. Recently developed conversion and deposition type surface coatings are thoroughly discussed by reporting their essential therapeutic responses like osteogenesis, angiogenesis, cytocompatibility, hemocompatibility, anti-bacterial, and controlled drug release towards in-vitro and in-vivo study models. The challenges associated with metallic, ceramic and polymeric coatings along with merits and demerits of various coatings have been illustrated. The use of multilayered hybrid coating comprising a unique combination of organic and inorganic components has been emphasized with future perspectives to obtain diverse bio-functionalities in a facile single coating system for orthopedic implant applications.

•

The challenges and current status of coatings are reviewed in light of clinical requirements.

•

Multilayered hybrid coatings have been emphasized to obtain diverse bio-functionalities.

•

The future developments and research directions on coatings for biodegradable implants are highlighted.

Zwitterionic coating assisted by dopamine with metal-phenolic networks loaded on titanium with improved biocompatibility and antibacterial property for artificial heart

Introduction: Titanium (Ti) and Ti-based alloy materials are commonly used to develop artificial hearts. To prevent bacterial infections and thrombus in patients with implanted artificial hearts, long-term prophylactic antibiotics and anti-thrombotic drugs are required, and this may lead to health complications. Therefore, the development of optimized antibacterial and antifouling surfaces for Ti-based substrate is especially critical when designing artificial heart implants. Methods: In this study, polydopamine and poly-(sulfobetaine methacrylate) polymers were co-deposited to form a coating on the surface of Ti substrate, a process initiated by Cu²⁺ metal ions. The mechanism for the fabrication of the coating was investigated by coating thickness measurements as well as Ultraviolet-visible and X-ray Photoelectron (XPS) spectroscopy. Characterization of the coating was observed by optical imaging, scanning electron microscope (SEM), XPS, atomic force microscope (AFM), water contact angle and film thickness. In addition, antibacterial property of the coating was tested using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as model strains, while the material biocompatibility was assessed by the antiplatelet adhesion test using platelet-rich plasma and in vitro cytotoxicity tests using human umbilical vein endothelial cells and red blood cells. Results and discussion: Optical imaging, SEM, XPS, AFM, water contact angle, and film thickness tests demonstrated that the coating was successfully deposited on the Ti substrate surface. The biocompatibility and antibacterial assays showed that the developed surface holds great potential for improving the antibacterial and antiplatelet adhesion properties of Ti-based heart implants.

Research Progress of Polydopamine Hydrogel in the Prevention and Treatment of Oral Diseases

Oral diseases represent one of the most prevalent diseases globally and are associated with serious health and economic burdens, greatly altering the quality of life of affected individuals. Various biomaterials play important roles in the treatment of oral diseases. To some extent, the development of biomaterials has promoted progress in clinically available oral medicines. Hydrogels have unique tunable advantages that make them useful in the next generation of regenerative strategies and have been widely applied in both oral soft and hard tissues repair. However, most hydrogels lack self-adhesive properties, which may result in low repair efficacy. Polydopamine (PDA), the primary adhesive component, has attracted increasing attention in recent years. PDA-modified hydrogels exhibit reliable and suitable adherence to tissues and easily integrate into tissues to promote repair efficiency. This paper reviews the latest research progress on PDA hydrogels and elaborates on the mechanism of the reaction between PDA functional groups and hydrogels, and summarizes the biological properties and the applications of PDA hydrogels in the prevention and treatment of the field of oral diseases. It is also proposed that in future research we should simulate the complex microenvironment of the oral cavity as much as possible, coordinate and plan various biological events rationally, and realize the translation from scientific research to clinical practice.

Molecular Dynamics Simulations of Polydopamine Nanosphere's Structure Based on Experimental Evidence

In this work, we show how to obtain internal monodispersed gold nanoparticles inside polydopamine (PDA) nanospheres that are also externally decorated with gold. The number of internal nanoparticles is affected by the size of the PDA nanosphere used, and the lower limit in the number of gold nanoparticles in the center of decorated nanospheres, one single gold nanoparticle, has been reached. In addition, extensive molecular dynamics simulations of PDA nanospheres based on four different chemical motifs, in the presence of water and with different sizes, have been performed to gain insight into the arrangements capable of accommodating cavities. In particular, PDA nanospheres based on pyranoacridinotrione (PYR) units provide good agreement with the experimental attainment of internal metal nanoparticles. In these, the stacking of PYR units leads to a particular morphology, with large portions of space occupied by the solvent, that would explain the observed formation of gold nanoparticles inside the PDA nanosphere.

A Biomimetic Smart Nanoplatform as “Inflammation Scavenger” for Regenerative Therapy of Periodontal Tissue

Introduction

The functional reconstruction of periodontal tissue defects remains a clinical challenge due to excessive and prolonged host response to various endogenous and exogenous pro-inflammatory stimuli. Thus, a biomimetic nanoplatform with the capability of modulating inflammatory response in a microenvironment-responsive manner is attractive for regenerative therapy of periodontal tissue.

Methods

Herein, a facile and green design of engineered bone graft materials was developed by integrating a biomimetic apatite nanocomposite with a smart-release coating, which could realize inflammatory modulation by “on-demand” delivery of the anti-inflammatory agent through a pH-sensing mechanism.

Results

In vitro and in vivo experiments demonstrated that this biocompatible nanoplatform could facilitate the clearance of reactive oxygen species in human periodontal ligament stem cells under inflammatory conditions via inhibiting the production of endogenous proinflammatory mediators, in turn contributing to the enhanced healing efficacy of periodontal tissue. Moreover, this system exhibited effective antimicrobial activity against common pathogenic bacteria in the oral cavity, which is beneficial for the elimination of exogenous pro-inflammatory factors from bacterial infection during healing of periodontal tissue.

Conclusion

The proposed strategy provides a versatile apatite nanocomposite as a promising “inflammation scavenger” and propels the development of intelligent bone graft materials for periodontal and orthopedic applications.

Polydopamine/IR820 nanoparticles as topical phototheranostics for inhibiting psoriasiform lesions through dual photothermal and photodynamic treatments

Dual photothermal and photodynamic therapy (PTT and PDT) is an attractive approach that generates a synergistic effect for inhibiting keratinocyte hyperproliferation in the treatment of psoriasis. Here, we developed phototheranostic nanocarriers capable of producing hyperthermia and reactive oxygen species (ROS) in response to near-infrared (NIR) illumination. To this end, IR820 with photothermal and photodynamic features was embedded in nano-sized polydopamine (PDA) acting as a PTT agent. A comprehensive characterization of the PDA/IR820 nanosystem was performed according to its morphology, size, zeta potential, UV absorbance, and heat generation. Its therapeutic efficacy was assessed by a keratinocyte-based study and using an imiquimod (IMQ)-stimulated psoriasiform murine model. PDA/IR820 nanoparticles were facilely internalized into keratinocytes and mainly resided in lysosomes. Upon irradiation with NIR light, ROS were generated inside the keratinocytes to cause a photodynamic effect. The live/dead cell assay and cytotoxicity assay demonstrated that PDA and IR820 acted as effective photoabsorbers to induce keratinocyte death. The highest cytotoxic effect was detected in the group of NIR-irradiated PDA/IR820 nanoparticles, which killed 52% of keratinocytes. The nanosystem acted through the caspase and poly ADP-ribose polymerase (PARP) pathways to induce keratinocyte apoptosis. In vitro and in vivo skin permeation indicated the selective accumulation of the topically applied PDA/IR820 nanoparticles within psoriasiform skin, suggesting their skin-targeting capability. The combination of PDA/IR820 nanoparticles and NIR irradiation increased the skin temperature by 11.7 °C. PTT/PDT eliminated psoriasiform plaques in mice by decreasing hyperplasia, inhibiting cytokine overexpression, and recovering the barrier function. The epidermal thickness of the IMQ-treated skin was reduced from 134 to 34 μm by the nanocarriers plus NIR. The IR820 nanoparticles were largely deposited on the inflamed areas of psoriasiform lesions for monitoring the severity of inflammation. The image-guided phototheranostic nanoparticles showed their potential for applications in psoriasis management via noninvasive topical administration.

Polyester-Polydopamine Copolymers for Intravitreal Drug Delivery: Role of Polydopamine Drug-Binding Properties in Extending Drug Release

This work reports on a novel polyester copolymer containing poly(dopamine), a synthetic analogue of natural melanin, evaluated in a sustained-release drug delivery system for ocular intravitreal administration of drugs. More specifically, a graft copolymer of poly(ε-caprolactone)-graft-poly(dopamine) (PCL-g-PDA) has been synthesized and was shown to further extend the drug release benefits of state-of-the-art biodegradable intravitreal implants composed of poly(lactide) and poly(lactide-co-glycolide). The innovative biomaterial combines the documented drug-binding properties of melanin naturally present in the eye, with the established ocular tolerability and biodegradation of polyester implants. The PCL-g-PDA copolymer was obtained by a two-step modification of PCL with a final PDA content of around 2-3 wt % and was fully characterized by size exclusion chromatography, NMR, and diffusion ordered NMR spectroscopy. The thermoplastic nature of PCL-g-PDA allowed its simple processing by hot-melt compression molding to prepare small implants. The properties of unmodified PCL and PCL-g-PDA implants were studied and compared in terms of thermal properties (differential scanning calorimetry), thermal stability (thermogravimetry analysis), degradability, and in vitro cytotoxicity. PCL and PCL-g-PDA implants exhibited similar degradation properties in vitro and were both stable under physiological conditions over 110 days. Likewise, both materials were non-cytotoxic toward L929 and ARPE-19 cells. The drug loading and in vitro release properties of the new materials were investigated with dexamethasone (DEX) and ciprofloxacin hydrochloride (CIP) as representative drugs featuring low and high melanin-binding affinities, respectively. In comparison to unmodified PCL, PCL-g-PDA implants showed a significant extension of drug release, most likely because of specific drug-catechol interaction with the PDA moieties of the copolymer. The present study confirms the advantages of designing PDA-containing polyesters as a class of biodegradable and biocompatible thermoplastics that can modulate and remarkably extend the drug release kinetics thanks to their unique drug-binding properties, especially, but not limited to, for ocular applications.

Dopamine facilitates Al2O3film growth on polyethylene terephthalate by low-temperature plasma-enhanced atomic layer deposition

Polymeric materials, including polyethylene terephthalate (PET), are widely used in various fields because of their beneficial properties. Functional films are deposited on these materials through different approaches, such as plasma-enhanced atomic layer deposition (PEALD), to enhance their performance and prolong their life span. However, the inert and thermally fragile nature of most polymers hinders deposition. We developed a strategy for the PEALD of nanoscale Al₂O₃films on PET substrates. First, a PET substrate is subjected to alkali treatment, which gives it basic hydrophilicity for the subsequent dopamine modification. After 24 h of dopamine deposition, the substrate shows adequate active sites (phenolic hydroxyl groups), which can chemisorb large amounts of precursor during the initial deposition. The island growth mode was observed during the PEALD processes. We analyzed the detailed chemical components of Al₂O₃on alkali-treated PET and dopamine-modified PET. After 100 cycles of deposition, the Al₂O₃films on both samples contained much hydrogen. Benefitting from the more active sites, we observed more continuous Al₂O₃film on dopamine-modified PET, which exhibited excellent water vapor blocking performance. Our findings suggest that dopamine could act as a 'bridge' between polymers and PEALD functional films.

Bioactive Flavonoid used as a Stabilizing Agent of Mono and Bimetallic Nanomaterials for Multifunctional Activities

The multifunctional features of noble metal nanoparticles (MNPs) were exploited in various biomedical applications, which eventually demanded the development of a sustainable green synthesis approach. In the present study, Quercetin (Q) was employed as a promising green reductant for the generation of noble metal nanoparticles such as silver (Q-AgNPs), gold (Q-AuNPs), and bimetallic (Q-Ag-AuNPs) towards biomedical perspective. Initially, the NPs were successfully synthesized in a size-controlled manner via optimizing temperature, pH, metal ion concentration, and stoichiometric ratio of the reaction mix. The redox reaction and conversion of metal ions (Ag+ and Au3+) into their respective metal nano-forms were confirmed through their surface plasmonic resonance (SPR) in UV-visible spectroscopy. In addition, different instrumentation like FT-IR, XRD, HR-TEM, and XPS analyses were performed to confirm the size, shape, and chemical composition of fabricated NPs. The bactericidal effect of fabricated NPs was tested against Gram-positive and Gram-negative pathogens. Moreover, the cytotoxic potential was screened against breast (MCF-7) and colorectal (HCT-116) carcinoma cell lines. This work revealed that the flavonoid-functionalized noble metal NPs were associated with good antibacterial and anticancer potential against selected cancer cell lines.

Hybrid Ag nanoparticles/polyoxometalate-polydopamine nano-flowers loaded chitosan/gelatin hydrogel scaffolds with synergistic photothermal/chemodynamic/Ag+ anti-bacterial action for accelerated wound healing

Bacterial infections significantly slow the wound healing process, thus severely threatening human health. Furthermore, traditional antibiotics may promote the development of multidrug-resistant bacteria. Therefore, developing novel bactericides and therapeutic strategies for bacterial infections is important to enhance wound healing. Herein, a three-in-one bactericidal flower-like nanocomposite was assembled using Ag nanoparticles/phosphotungstic acid-polydopamine nano-flowers (AgNPs/POM-PDA). The nanocomposite exhibited photothermal therapy (PTT) when exposed to NIR light via photothermal conversion by PDA. The resultant photothermal effect accelerated and controlled the Ag⁺ released from AgNPs. The chemodynamic therapy (CDT) was obtained via POM catalytic Fenton-like reaction. The combined PTT/CDT/Ag⁺ treatment achieved excellent synergistic anti-bacterial activity against both gram-negative E. coli and gram-positive S. aureus. A multifunctional wound dressing was then obtained by embedding the AgNPs/POM-PDA flower-like nanocomposite into the chitosan (CS)/gelatin (GE) biocomposite hydrogel. The synergy of AgNPs/POM-PDA nanocomposites and CS/GE hydrogel remarkably accelerated wound healing in vivo due to the excellent biocompatibility, hydroabsorptivity, and breathability of the hydrogel. In this study, a multifunctional agent was developed to synergistically combat bacterial infections and accelerate wound healing.