Robust ZIF-8/alginate fibers for the durable and highly effective antibacterial textiles

Oxygen Self-Supplied Nanoplatform for Enhanced Photodynamic Therapy against Enterococcus Faecalis within Root Canals

The successful treatment of persistent and recurrent endodontic infections hinges upon the eradication of residual microorganisms within the root canal system, which urgently needs novel drugs to deliver potent yet gentle antimicrobial effects. Antibacterial photodynamic therapy (aPDT) is a promising tool for root canal infection management. Nevertheless, the hypoxic microenvironment within the root canal system significantly limits the efficacy of this treatment. Herein, a nanohybrid drug, Ce6/CaO2/ZIF-8@polyethylenimine (PEI), is developed using a bottom-up strategy to self-supply oxygen for enhanced aPDT. PEI provides a positively charged surface, which enables precise targeting of bacteria. CaO2 reacts with H2O to generate O2, which alleviates the hypoxia in the root canal and serves as a substrate for Ce6 under 660 nm laser irradiation, leading to the successful eradication of planktonic Enterococcus faecalis (E. faecalis) and biofilm in vitro and, moreover, the effective elimination of mature E. faecalis biofilm in situ within the root canal system. This smart design offers a viable alternative for mitigating hypoxia within the root canal system to overcome the restricted efficacy of photosensitizers, providing an exciting prospect for the clinical management of persistent endodontic infection.

Preparation of Antibacterial Biobased Fibers by Triaxial Microfluidic Spinning Technology Using Ionic Liquids as the Solvents

Bacterial infections have become a serious threat to public health. The utilization of antibacterial textiles offers an effective way to combat bacterial infections at the source, instead of relying solely on antibiotic consumption. Herein, efficient and durable antibacterial fibers based on quercetin and cellulose were prepared by a triaxial microfluidic spinning technology using ionic liquids (ILs) as the solvents. It was indicated that the structure and properties of the antibacterial fibers were affected by the type of IL and the flow rates during the triaxial microfluidic spinning process. Quercetin regenerated from [Emim]Ac underwent structural transformation and obtained an increased water solubility, while quercetin regenerated from [Emim]DEP remained unchanged, which was proven by FI-IR, XRD, and UV analyses. Furthermore, antibacterial fibers regenerated from [Emim]Ac exhibited the highest antibacterial activity of 96.9% against S. aureus, achieved by reducing the inner-to-outer flow rate ratio to 0 and concentrating quercetin at the center of fibers. On the other hand, when [Emim]DEP was used as the solvent, balancing the inner-to-outer flow rate ratio to concentrate quercetin in the middle layer of the fiber was optimal for achieving the best antibacterial activity of 93.3% because it promised both the higher encapsulation efficiency and release rate. Computational fluid dynamics (CFD) mathematically predicted the solvent exchange process during triaxial spinning, explaining the influence of IL types and flow rates on quercetin distribution and encapsulation efficiency. It was indicated that optimizing the distribution of antibacterial agents within the fibers can fully unleash its antibacterial potential while preserving the mechanical properties of the fiber. Therefore, the proposed simple triaxial spinning strategy provides valuable insights into the design of biomedical materials.

Tunable Zeolitic Imidazolate Framework-8 Nanoparticles for Biomedical Applications

Zeolite imidazole framework-8 (ZIF-8) is the most prestigious one among zeolitic imidazolate framework (ZIF) with tunable dimensions and unique morphological features. Utilizing its synthetic adjustability and structural regularity, ZIF-8 exhibits enhanced flexibility, allowing for a wide range of functionalities, such as loading of nanoparticle components while preserving biomolecules activity. Extensive efforts are made from investigating synthesis techniques to develop novel applications over decades. In this review, the development and recent progress of various synthesis approaches are briefly summarized. In addition, its interesting properties such as adjustable porosity, excellent thermal, and chemical stabilities are introduced. Further, five representative biomedical applications are highlighted based on above physicochemical properties. Finally, the remaining challenges and offered insights into the future outlook are also discussed. This review aims to understand the co-relationships between structures and biomedical functionalities, offering the opportunity to construct attractive materials with promising characteristics.

Research progress on antibacterial applications of metal-organic frameworks and their biomacromolecule composites

With the extensive use of antibiotics, resulting in increasingly serious problems of bacterial resistance, antimicrobial therapy has become a global concern. Metal-organic frameworks (MOFs) are low-density porous coordination materials composed of metal ions and organic ligands, which can form composite materials with biomacromolecules such as proteins and polysaccharides. In recent years, MOFs and their derivatives have been widely used in the antibacterial field as efficient antibacterial agents. This review offers a detailed summary of the antibacterial applications of MOFs and their composites, and the different synthesis methods and antibacterial mechanisms of MOFs and MOF-based composites are briefly introduced. Finally, the challenges and prospects of MOFs-based antibacterial materials in the rapidly developing medical field were briefly discussed. We hope this review will provide new strategies for the medical application of MOFs-based antibacterial materials.

Functionalization strategies of metal-organic frameworks for biomedical applications and treatment of emerging pollutants: A review

One of the representative coordination polymers, metal-organic frameworks (MOFs) material, is of hotspot interest in the multi field thanks to their unique structural characteristics and properties. As a novel hierarchical structural class, MOFs show diverse topologies, intrinsic behaviors, flexibility, etc. However, bare MOFs have less desirable biofunction, high humid sensitivity and instability in water, restraining their efficiencies in biomedical and environmental applications. Thus, a structural modification is required to address such drawbacks. Herein, we pinpoint new strategies in the synthesis and functionalization of MOFs to meet demanding requirements in in vitro tests, i.e., antibacterial face masks against corona virus infection and in wound healing and nanocarriers for drug delivery in anticancer. Regarding the treatment of wastewater containing emerging pollutants such as POPs, PFAS, and PPCPs, functionalized MOFs showed excellent performance with high efficiency and selectivity. Challenges in toxicity, vast database of clinical trials for biomedical tests and production cost can be still presented. MOFs-based composites can be, however, a bright candidate for reasonable replacement of traditional nanomaterials in biomedical and wastewater treatment applications.

Metal-organic gels: recent advances in their classification, characterization, and application in the pharmaceutical field

Metal-organic gels (MOGs) are a type of functional soft substance with a three-dimensional (3D) network structure and solid-like rheological behavior, which are constructed by metal ions and bridging ligands formed under the driving force of coordination interactions or other non-covalent interactions. As the homologous substances of metal-organic frameworks (MOFs) and gels, they exhibit the potential advantages of high porosity, flexible structure, and adjustable mechanical properties, causing them to attract extensive research interest in the pharmaceutical field. For instance, MOGs are often used as excellent vehicles for intelligent drug delivery and programmable drug release to improve the clinical curative effect with reduced side effects. Also, MOGs are often applied as advanced biomedical materials for the repair and treatment of pathological tissue and sensitive detection of drugs or other molecules. However, despite the vigorous research on MOGs in recent years, there is no systematic summary of their applications in the pharmaceutical field to date. The present review systematically summarize the recent research progress on MOGs in the pharmaceutical field, including drug delivery systems, drug detection, pharmaceutical materials, and disease therapies. In addition, the formation principles and classification of MOGs are complemented and refined, and the techniques for the characterization of the structures/properties of MOGs are overviewed in this review.

Wool keratin/zeolitic imidazolate framework-8 composite shape memory sponge with synergistic hemostatic performance for rapid hemorrhage control

Uncontrollable hemorrhage and subsequent wound infection pose severe threats to life, especially in the case of deep, non-compressible, massive bleeding. Here, a wool keratin/zeolitic imidazolate framework-8 (WK/ZIF-8) composite shape memory sponge is prepared by incorporating ZIF-8 nanoparticles into wool keratin. The combination of keratin and ZIF-8 particles not only reduces the effect of ZIF-8 particles on cell viability but also bolsters the mechanical properties of the keratin sponge and endows it with antibacterial efficacy. Due to the synergistic effect of the excellent hemostatic performance of keratin and Zn2+ release from ZIF-8 nanoparticles, the porous structure suitable for blood cell adhesion and the shape recovery ability of sponges, the WK/ZIF-8 composite sponge exhibits superior hemostatic performance to commercial medical sponges in SD rat and rabbit hemorrhage models. In addition, in vitro and in vivo antibacterial experiments demonstrate the anti-infection activity of the composite sponge. Overall, the WK/ZIF-8 composite sponge provides a promising approach to rapidly control bleeding and promote wound healing.

Nanopatterned Electroactive Polylactic Acid Nanofibrous MOFilters for Efficient PM0.3 Filtration and Bacterial Inhibition

Biodegradable polylactic acid (PLA) nanofibrous membranes (NFMs) hold great potential to address the increasing airborne particulate matter (PM) and dramatic accumulation of plastic/microplastic pollution. However, the field of PLA NFM-based filters is still in its infancy, frequently dwarfed by the bottlenecks regarding relatively low surface activity, poor electroactivity, and insufficient PM capturing mechanisms. This effort discloses a microwave-assisted approach to minute-level synthesis of dielectric ZIF-8 nanocrystals with high specific surface area (over 1012 m2/g) and ultrasmall size (∼240 nm), which were intimately anchored onto PLA nanofibers (PLA@ZIF-8) by a combined "electrospinning-electrospray" strategy. This endowed the PLA@ZIF-8 NFMs with largely increased electroactivity in terms of elevated dielectric coefficient (an increase of 202%), surface potential (up to 5.8 kV), and triboelectric properties (output voltage of 30.8 V at 10 N, 0.5 Hz). Given the profound control over morphology and electroactivity, the PLA@ZIF-8 NFMs exhibited efficient filtration of PM0.3 (97.1%, 85 L/min) with a decreased air resistance (592.5 Pa), surpassing that of the pure PLA counterpart (88.4%, 650.9 Pa). This was essentially ascribed to realization of multiple filtration mechanisms for PLA@ZIF-8 NFMs, including enhanced physical interception, polar interactions, and electrostatic adsorption, and the unique self-charging function triggered by airflow vibrations. Moreover, perfect antibacterial performance was achieved for PLA@ZIF-8, showing ultrahigh inhibition rates of 99.9 and 100% against E. coli and S. aureus, respectively. The proposed hierarchical structuring strategy, offering the multifunction integration unattainable with conventional methods, may facilitate the development of biodegradable long-term air filters.

Chitosan and TiO2 functionalized polypropylene nonwoven fabrics with visible light induced photocatalytic antibacterial performances

Chitosan/TiO2 functionalized polypropylene (CS/TiO2/PP) nonwoven fabrics were fabricated through crosslinking of chitosan with glutaraldehyde followed by loading of TiO2 nanoparticles. The functionalized CS/TiO2/PP has super hydrophilicity and excellent visible light induced photocatalytic antibacterial properties owing to the synergistic effects of CS and TiO2. The photocatalytic degradation performance was determined by assessing the degradation of methyl blue under simulated visible light irradiation and its recyclability was also evaluated. In addition, SEM images demonstrated that TiO2 nanoparticles were distributed evenly on the surface of the 2 g/L CS/TiO2/PP. Meanwhile, the polypropylene surface showed a significant increase in hydrophilicity after being treated with chitosan and TiO2. The photocatalytic degradation results revealed that CS/TiO2/PP had higher photocatalytic properties than those of pure PP under visible light, and the degradation rate of methylene blue reached 96.4 % after 90 min of light exposure. Compared to pure PP, the antibacterial properties of CS/TiO2/PP significantly increased, and the bacterial reduction percentages were increased to 98.7 % and 96.3 %, against E. coli and S. aureus, respectively. The functionalized CS/TiO2/PP composites exhibited promising potential in environmentally friendly antibacterial materials.

Cellulose/Zeolitic Imidazolate Framework (ZIF-8) Composites with Antibacterial Properties for the Management of Wound Infections

Metal-organic frameworks (MOFs) are a class of crystalline porous materials with outstanding physical and chemical properties that make them suitable candidates in many fields, such as catalysis, sensing, energy production, and drug delivery. By combining MOFs with polymeric substrates, advanced functional materials are devised with excellent potential for biomedical applications. In this research, Zeolitic Imidazolate Framework 8 (ZIF-8), a zinc-based MOF, was selected together with cellulose, an almost inexhaustible polymeric raw material produced by nature, to prepare cellulose/ZIF-8 composite flat sheets via an in-situ growing single-step method in aqueous media. The composite materials were characterized by several techniques (IR, XRD, SEM, TGA, ICP, and BET) and their antibacterial activity as well as their biocompatibility in a mammalian model system were investigated. The cellulose/ZIF-8 samples remarkably inhibited the growth of Gram-positive and Gram-negative reference strains, and, notably, they proved to be effective against clinical isolates of Staphylococcus epidermidis and Pseudomonas aeruginosa presenting different antibiotic resistance profiles. As these pathogens are of primary importance in skin diseases and in the delayed healing of wounds, and the cellulose/ZIF-8 composites met the requirements of biological safety, the herein materials reveal a great potential for use as gauze pads in the management of wound infections.

Oriented ascorbic acid onto zeolitic metal-organic framework-8 membrane via microfluidic spinning for biomedical care

Nowadays, the hydrogen dressing and electrostatic spun films widely used on wounds do not facilitate the permeability of the wound area and fail to achieve controlled drug delivery. Therefore, finding a wound dressing with both breathability and targeted drug delivery has remained an unmet challenge. Here, an oriented microstructure membrane with sustained drug release and robust antibacterial performance was constructed through the microfluidic spinning method. The multifunctional oriented membrane was prepared by loading ascorbic acid onto the zeolitic metal-organic framework-8 to develop drug delivery nanomaterial zeolitic metal-organic framework-8 @ascorbic acid (ZIF-8 @AA) and then mixing ZIF-8 @AA with polyvinyl pyrrolidone (PVP) solution via microfluidic technology, which produced an oriented microfiber member. In addition, the spinning parameters, including the fluid content, rotation speed, and flow rate, on microfiber diameter were evaluated. The constructed oriented membrane had bactericidal efficiencies of 82.94% ± 2.79% and 95.96% ± 1.54% against E. coli and S. aureus, respectively. After five days, the membrane still has a sustained release. Moreover, the fabricated membrane also has good biocompatibility and hemocompatibility in vitro. The oriented arrangement strategy provides a promising approach for wound healing materials in targeted drug delivery. Furthermore, this strategy offers a feasible idea for loading active materials into substrates for disease treatment in the biomedical field.

Coaxial microfluidic spinning design produced high strength alginate membranes for antibacterial activity and drug release

Directional drug delivery and sufficient strength are two conditions that need to be met for wound dressing. In this paper, an oriented fibrous alginate membrane with sufficient strength was constructed via coaxial microfluidic spinning, and zeolitic imidazolate framework-8/ascorbic acid was used to realize drug delivery and antibacterial activity. The effects of the process parameters of the coaxial microfluidic spinning on the mechanical properties of the alginate membrane were discussed. In addition, it was found that the antimicrobial activity mechanism of zeolitic imidazolate framework-8 was attributed to the disruptive effect of reactive oxygen species (ROS) on bacteria, and the quantitative amount of generated ROS were evaluated by detecting •OH and H₂O₂. Furthermore, a mathematical drug diffusion model was established and showed high consistency with the experimental data (R² = 0.99). This study provides a new idea for the preparation of dressing materials with high strength and directional drug delivery and also provides some guidance for the development of coaxial microfluidic spin technology to be used in functional materials for drug release.

The preparation of ultrathin and porous electrospinning membranes of HKUST-1/PLA with good antibacterial and filtration performances

Developing degradable filter membranes that inhibit bacterial infection for preventing particle matter and infectious disease has been a research hotspot. Here, the fiber membranes of polylactic acid (PLA)/HKUST-1 with porous structure through the entire fiber matrix were prepared by electrospinning method. Due to the HKUST-1 incorporation and the presence of pore through fiber, the hydrophobicity of prepared membranes had been improved. The PLA/HKUST-1 membranes exhibited the good antibacterial activity against Escherichia coli and Staphylococcus aureus , and the antibacterial rate for S. aureus reached 99.99%. The filtration performance of PLA/HKUST-1 membranes was better than that of the melt-blown fabric although their thickness was only about one-third of the thickness of the currently commercial polypropylene melt-blown fabric.

How Efficient are Alendronate-Nano/Biomaterial Combinations for Anti-Osteoporosis Therapy? An Evidence-Based Review of the Literature

Osteoporosis is defined as a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. Because of the systemic nature of osteoporosis, the associated escalation in fracture risk affects virtually all skeletal sites. The problem is serious since it is estimated that more than 23 million men and women are at high risk of osteoporotic-like breakages in the European Union. Alendronate (ALN) is the most commonly prescribed oral nitrogen-containing bisphosphonate (BP) for the prevention and the therapy of osteoporosis. This is also one of the most intensely studied drugs in this field. However, ALN is characterized by restricted oral absorption and bioavailability and simultaneously its administration has serious side-effects (jaw osteonecrosis, irritation of the gastrointestinal system, nausea, musculoskeletal pain, and cardiovascular risks). Therefore, delivery systems enabling controlled release and local action of this drug are of great interest, being widely researched and presented in the literature. In this review, we discuss the current trends in the design of various types of alendronate carriers. Our paper is focused on the most recent developments in the field of nano/biomaterials-based systems for ALN delivery, including nano/microformulations, synthetic/natural polymeric and inorganic materials, hydrogel-based materials, scaffolds, coated-like structures, as well as organic-inorganic hybrids. Topics related to the treatment of complex bone diseases including osteoporosis have been covered in several more general reviews; however, the systems for this particular drug have not yet been discussed in detail.

Thermally Treated Berberine-Loaded SA/PVA/PEO Electrospun Microfiber Membranes for Antibacterial Wound Dressings

This study aimed to develop a safe and advanced antibacterial material of electrospun microfiber membranes (MFMs) for wound dressings. Combinations of several materials were investigated; thermal treatment and electrospinning techniques were used to form the best quality of MFMs to suit its end applications. By comparing the fiber morphology, diameter changes, and fracture strength, the suitable ratio of raw materials and thermal treatment were obtained before and after adding Trition X-100 as a surfactant for MFMs of sodium alginate/polyvinyl alcohol/polyethylene oxide (SA/PVA/PEO). The electrospinning solution was mixed with berberine as an antibacterial substance; meanwhile, calcium chloride (CaCl₂) was used as the crosslinking agent. The antibacterial properties, water dissolution resistance, water content, and fracture strength were thoroughly investigated. The results showed that the antibacterial rates of MFMs with different mass fractions of berberine (0, 3, and 5 wt.%) to Escherichia coli (E. coli) were 14.7, 92.9, and 97.2%, respectively. The moisture content and fracture strength of MFMs containing 5 wt.% berberine were 72.0% and 7.8 MPa, respectively. In addition, the produced MFMs embodied great water dissolution resistance. Berberine-loaded SA/PVA/PEO MFMs could potentially serve as an antibacterial wound dressing substrate with low cost and small side effects.

Bead-like carbon fibers consisting of abundantly exposed active sites for the oxygen reduction reaction

Rational design is essential in the synthesis of electrocatalysts for the oxygen reduction reaction (ORR). Herein, we introduced zeolitic imidazolate framework-8 (ZIF-8) and polyvinyl pyrrolidone (PVP) into the electrospinning process of the polyacrylonitrile (PAN) and hemin to increase the active site loading and exposed active area of the final product with empty bead-like structures. In this method, ZIF-8 acts as a carbon skeleton to provide a rich microporous structure that can support active sites, and as a nitrogen dopant to improve nitrogen contents. PVP changes the properties of the spinning solution, adjusts the fiber morphology, and to increase the exposed area of active sites as a pore former. The obtained Fe-N-C ORR catalyst delivered a half-wave potential (E_1/2) of 0.924 V in a 0.1 M KOH solution and 0.77 V in a 0.1 M HClO₄solution. A homemade zinc air battery with power density of 236 mW cm^-2demonstrated the excellent performance of the catalyst under working conditions.

ZIF-8/PI Nanofibrous Membranes With High-Temperature Resistance for Highly Efficient PM0.3 Air Filtration and Oil-Water Separation

Air and water pollution poses a serious threat to public health and the ecological environment worldwide. Particulate matter (PM) is the major air pollutant, and its primary sources are processes that require high temperatures, such as fossil fuel combustion and vehicle exhaust. PM_0.3 can penetrate and seriously harm the bronchi of the lungs, but it is difficult to remove PM_0.3 due to its small size. Therefore, PM_0.3 air filters that are highly efficient and resistant to high temperatures must be developed. Polyimide (PI) is an excellent polymer with a high temperature resistance and a good mechanical property. Air filters made from PI nanofibers have a high PM removal efficiency and a low air flow resistance. Herein, zeolitic imidazolate framework-8 (ZIF-8) was used to modify PI nanofibers to fabricate air filters with a high specific surface area and filtration efficiency. Compared with traditional PI membranes, the ZIF-8/PI multifunction nanofiber membranes achieved super-high filtration efficiency for ultrafine particles (PM_0.3, 100%), and the pressure drop was only 63 Pa. The filtration mechanism of performance improvement caused by the introduction of ZIF-8/PI nanofiber membrane is explored. Moreover, the ZIF-8/PI nanofiber membranes exhibited excellent thermal stability (300 C) and efficient water–oil separation ability (99.85%).

Preparation of Ag@ZIF-8@PP Melt-Blown Nonwoven Fabrics: Air Filter Efficacy and Antibacterial Effect

Serving as matrices, polypropylene (PP) melt-blown nonwoven fabrics with 4% electrostatic electret masterbatch were incorporated with a 6%, 10%, 14%, or 18% phosphorus-nitrogen flame retardant. The test results indicate that the incorporation of the 6% flame retardant prevented PP melt-blown nonwoven fabrics from generating a molten drop, which, in turn, hampers the secondary flame source while increasing the fiber diameter ratio. With a combination of 4% electrostatic electret masterbatch and the 6% flame retardant, PP melt-blown nonwoven fabrics were grafted with ZIF-8 and Ag@ZIF-8. The antibacterial effect of ZIF-8 and Ag@ZIF-8 was 40% and 85%, respectively. Moreover, four reinforcing measures were used to provide Ag@ZIF-8 PP melt-blown nonwoven fabrics with synergistic effects, involving lamination, electrostatic electret, and Ag@ZIF-8 grafting, as well as a larger diameter because of the addition of phosphorus-nitrogen flame retardants. As specified in the GB2626-2019 and JIS T8151-2018 respiratory resistance test standards, with a constant 60 Pa, Ag@ZIF-8 PP melt-blown nonwoven membranes were tested for a filter effect against PM 0.3. When the number of lamination layers was five, the filter effect was 88 ± 2.2%, and the respiratory resistance was 51 ± 3.6 Pa.

Two methods for constructing ZIF-8 nanomaterials with good bio compatibility and robust antibacterial applied to biomedical

Metal-organic framework materials not only possess porous structures, but also have excellent antibacterial properties. It is of great practical significance to prepare new antibacterial materials with excellent antibacterial effect by metal-organic framework materials. In our study, Zeolitic Imidazolate Framework-8 (ZIF-8) nanomaterials with antibacterial properties were prepared via the solvent method and diethanolamine template method. The materials were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), cold field-emission scanning electron microscope (SEM), transmission electron microscopy (TEM), N₂ adsorption-desorption experiment, antibacterial experiment, and biocompatibility experiment. Results showed that ZIF-8 prepared by solvent method has a more typical hexagonal structure, larger specific surface area, and smaller pore size, and the values are 1812.07 m²g^-1 and 2.2412 nm, respectively. At the same time, the materials prepared by the two methods have excellent antibacterial properties, and exhibit good biocompatibility at low concentrations, the antibacterial activity against Escherichia coli and Staphylococcus aureus are higher than 95%, and the cell viabilities of the selected five material concentrations of 12.5 µg mL^-1, 25 µg mL^-1, 50 µg mL^-1, 100 µg mL^-1 and 200 µg mL^-1 are more than 70%. Therefore, this study provides a feasible method for preparing Nano-scale antibacterial functional particles, and it is of great significance to broaden the application field of ZIF-8 materials and prepare ZIF-8 drug-delivery functional materials.

Preparation of Alginate-Based Biomaterials and Their Applications in Biomedicine

Alginates are naturally occurring polysaccharides extracted from brown marine algae and bacteria. Being biocompatible, biodegradable, non-toxic and easy to gel, alginates can be processed into various forms, such as hydrogels, microspheres, fibers and sponges, and have been widely applied in biomedical field. The present review provides an overview of the properties and processing methods of alginates, as well as their applications in wound healing, tissue repair and drug delivery in recent years.

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

Polydopamine (PDA) has shown great potentials in biomedical fields due largely to its unique physicochemical properties, including high photothermal transfer efficiency, excellent drug binding capacity, versatile adhesion ability, sensitive pH responsibility and great biocompatibility and biodegradability. These properties confer PDA-based nanoparticles the potentials either as the drug carriers for advanced drug delivery or as the bioactive agents for photothermal therapy, imaging and biosensing. This review aims to provide a comprehensive understanding of PDA, its polymerization mechanisms and the potentials of PDA-based nano-systems in treating various diseases, including cancer, diabetes, inflammation, bacterial infection and Parkinson's disease. In addition, the concerns of PDA in biomedical use are also discussed.