Kinetic study of polydopamine sphere synthesis using TRIS: relationship between synthesis conditions and final properties

Cisplatin Encapsulated Plasmonic Blackbodies for NIR Light Activatable Chemo-Phototherapy and Reduction of 4-Nitrophenol

Cisplatin (CDDP) is an FDA-approved chemotherapeutic drug used for treating various solid tumors. Despite of its effectiveness towards chemotherapy, it faces several challenges, such as multi-drug resistance (MDR) and significant damage to the normal tissues. To address these challenges, various nanoformulations were developed to improve the delivery and safety of CDDP. One of the limitation in these CDDP loaded nanoformulations is that the effective CDDP loading concentrations are very poor. Therefore, this leaves a grand challenge to develop an effective strategy to carry higher concentrations of CDDP molecules, and also simultaneously exhibit very unique properties. Herein, we have developed an one-pot synthesis of Cisplatin encapsulated Plasmonic blackbody (CiP), which offers a double play for near infrared (NIR) light activatable chemo-photothermal therapy in destructing cancer cells as well as mediate catalytic reduction of 4-nitrophenol (4-NP). The CiP nanoformulation exhibits superior light absorbing capabilities in the NIR region with an appreciable photothermal conversion efficiency of 41 %. Further, NIR light activatable combinatorial therapeutic approach of CiP was demonstrated against ovarian cancer cells and as a catalyst for the reduction of model pollutant 4-nitrophenol. Our findings highlight the potential of CiP as a versatile platform for light-activated combinatorial cancer therapy and environmental pollutant remediation.

Heterogenous Copper(0)-Assisted Dopamine Oxidation: A New Pathway to Controllable and Scalable Polydopamine Synthesis

In this study, we introduce an approach for synthesizing polydopamine (PDA) through the controlled oxidation of dopamine using metallic copper. Traditional methods of PDA synthesis often encounter challenges such as scalability, reproducibility, and control over polymerization. Our approach utilizes the catalytic properties of metallic copper in the presence of dissolved oxygen to generate reactive oxygen species (ROS) without additional chemicals. This process allows for precise control over dopamine oxidation, leading to reliable, materials and cost-effective upscalable PDA production. We investigated the reaction kinetics and the role of copper and ROS in dopamine oxidation, using several different experimental techniques. Our results demonstrate that, even at low pH, the copper-assisted method produces PDA with properties comparable to those synthesized through conventional means. We propose a mechanism for PDA synthesis that is initiated by oxygen adsorption onto copper surface, leading to the generation of various ROS which act as oxidizing agents in PDA synthesis. This method presents an advancement in the scalable and controlled production of PDA, with potential applications in various scientific and industrial fields.

Polydopamine-Based Biomaterials in Orthopedic Therapeutics: Properties, Applications, and Future Perspectives

Polydopamine is a versatile and modifiable polymer, known for its excellent biocompatibility and adhesiveness. It can also be engineered into a variety of nanoparticles and biomaterials for drug delivery, functional modification, making it an excellent choice to enhance the prevention and treatment of orthopedic diseases. Currently, the application of polydopamine biomaterials in orthopedic disease prevention and treatment is in its early stages, despite some initial achievements. This article aims to review these applications to encourage further development of polydopamine for orthopedic therapeutic needs. We detail the properties of polydopamine and its biomaterial types, highlighting its superior performance in functional modification on nanoparticles and materials. Additionally, we also explore the challenges and future prospects in developing optimal polydopamine biomaterials for clinical use in orthopedic disease prevention and treatment.

Biocompatible Hybrid Graphenic Thin Coatings on Flexible Substrates through Matrix-Assisted Pulsed Laser Evaporation (MAPLE)

This work reports the production of biocompatible thin layers for biomedical applications based on a graphene-like material (GL), a graphene-related material (GRM) obtained from carbon black. GL was combined in a hybrid fashion with polydopamine (pDA), a mussel-inspired water-resistant wet adhesive bonding obtained by the oxidative polymerization of dopamine (DA), and polyvinyl pyrrolidinone (PVP), a nontoxic synthetic polymer with intrinsic adhesion properties, to obtain a tighter adhesion of the thin layer to the substrate (silicone slices). Matrix-assisted pulsed laser evaporation (MAPLE) was used to coat PDMS slices with thin films of GL-pDA and GL-PVP directly from their frozen suspensions in water. The results indicate that the relevant chemical-physical characteristics of both thin films (evidenced by FTIR and AFM) were maintained after MAPLE deposition and that the films exhibit uniformity also at the nanometric level. After deposition, the GL-pDA and GL-PVP films underwent a biological survey toward murine fibroblasts (NIH3T3), human keratinocytes (HaCAT), and human cervical adenocarcinoma epithelial-like (HeLa) cells to assess the feasibility of this approach. Results indicate that both the GL-pDA and GL-PVP films did not perturb the biological parameters evaluated, including cytoskeleton alterations. Both hybrid films enhanced the effects of GL on cellular vitality across all cell lines. Specifically, the GL-pDA film exhibited a more stable effect over time (up to 72 h), whereas the GL-PVP film behaved similarly to the GL film in NIH3T3 and HeLa cell lines after long-term exposure. These promising results make the GL-pDA and GL-PVP films potential candidates for the manufacture of coated flexible devices for biomedical applications.

Comparative performance analysis of mussel-inspired polydopamine, polynorepinephrine, and poly-α-methyl norepinephrine in electrochemical biosensors

Polydopamine (PDA) has garnered significant interest for applications in biosensors, drug delivery, and tissue engineering. However, similar polycatecholamines like polynorepinephrine (PNE) with additional hydroxyl groups and poly-α-methylnorepinephrine (PAMN) with additional hydroxyl and methyl groups remain unexplored in the biosensing domain. This research introduces three innovative biosensing platforms composed of ternary nanocomposite based on reduced graphene oxide (RGO), gold nanoparticles (Au NPs), and three sister polycatecholamine compounds (PDA, PNE, and PAMN). The study compares and evaluates the performance of the three biosensing systems for the ultrasensitive detection of Mycobacterium tuberculosis (MTB). The formation of the nanocomposites was meticulously examined through UV-Visible, Raman, XRD, and FT-IR studies with FE-SEM and HR-TEM analysis. Cyclic voltammetry and differential pulse voltammetry measurements were also performed to determine the electrochemical characteristics of the modified electrodes. Electrochemical biosensing experiments reveal that the RGO-PDA-Au, RGO-PNE-Au, and RGO-PAMN-Au-based biosensors detected target DNA up to a broad detection range of 0.1 × 10-8 to 0.1 × 10-18 M, with a low detection limit (LOD) of 0.1 × 10-18, 0.1 × 10-16, and 0.1 × 10-17 M, respectively. The bioelectrodes were proved to be highly selective with excellent sensitivities of 3.62 × 10-4 mA M-1 (PDA), 7.08 × 10-4 mA M-1 (PNE), and 6.03 × 10-4 mA M-1 (PAMN). This study pioneers the exploration of two novel mussel-inspired polycatecholamines in biosensors, opening avenues for functional nanocoatings that could drive further advancements in this field.

Ozone-Induced Rapid and Green Synthesis of Polydopamine Coatings with High Uniformity and Enhanced Stability

The development of green, controllable, and simplified pathways for rapid dopamine polymerization holds significant importance in the field of polydopamine (PDA) surface chemistry. In this study, a green strategy is successfully devised to accelerate and control the polymerization of dopamine through the introduction of ozone (O3 ). The findings reveal that ozone serves as an eco-friendly trigger, significantly accelerating the dopamine polymerization process across a broad pH range, spanning from 4.0 to 10.0. Notably, the deposition rate of PDA coatings on a silicon wafer reaches an impressive value of ≈64.8 nm h-1 (pH 8.5), which is 30 times higher than that of traditional air-assisted PDA and comparable to the fastest reported method. Furthermore, ozone exhibits the ability to accelerate dopamine polymerization even under low temperatures. It also enables control over the inhibition-initiation of the polymerization process by regulating the "ON/OFF" mode of the ozone gas. Moreover, the ozone-induced PDA coatings demonstrate exceptional characteristics, including high homogeneity, good hydrophilicity, and remarkable chemical and mechanical stability. Additionally, the ozone-induced PDA coatings can be rapidly and effectively deposited onto a wide range of substrates, particularly those that are adhesion-resistant, such as polytetrafluoroethylene (PTFE).

A catch-and-release nano-based gene delivery system

The design of nanomaterial-based nucleic acid formulations is one of the biggest endeavours in the search for clinically applicable gene delivery systems. Biopolymers represent a promising subclass of gene carriers due to their physicochemical properties, biodegradability and biocompatibility. By modifying melanin-like polydopamine nanoparticles with poly-L-arginine and poly-L-histidine blends, we obtained a novel catch-and-release gene delivery system for efficient trafficking of pDNA to human cells. A synergistic interplay of nanoparticle-bound poly-L-arginine and poly-L-histidine was observed and evaluated for pDNA binding affinity, cell viability, gene release and transfection. Although the functionalisation with poly-L-arginine was crucial for pDNA binding, the resulting nanocarriers failed to release pDNA intracellularly, resulting in limited protein expression. However, optimal pDNA release was achieved through the co-formulation with poly-L-histidine, essential for pDNA release. This effect enabled the design of gene delivery systems, which were comparable to Lipofectamine in terms of transfection efficacy and the catch-and-release surface modification strategy can be translated to other nanocarriers and surfaces.

Polydopamine-Functionalized Bacterial Cellulose as Hydrogel Scaffolds for Skin Tissue Engineering

Bacterial cellulose (BC) is a natural polysaccharide polymer hydrogel produced sustainably by the strain Gluconacetobacter hansenii under static conditions. Due to their biocompatibility, easy functionalization, and necessary physicochemical and mechanical properties, BC nanocomposites are attracting interest in therapeutic applications. In this study, we functionalized BC hydrogel with polydopamine (PDA) without toxic crosslinkers and used it in skin tissue engineering. The BC nanofibers in the hydrogel had a thickness of 77.8 ± 20.3 nm, and they could be used to produce hydrophilic, adhesive, and cytocompatible composite biomaterials for skin tissue engineering applications using PDA. Characterization techniques, namely Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Raman spectroscopy, were performed to investigate the formation of polydopamine on the BC nanofibers. The XRD peaks for BC occur at 2θ = 14.65°, 16.69°, and 22.39°, which correspond to the planes of (100), (010), and (110) of cellulose type Iα. Raman spectroscopy confirmed the formation of PDA, as indicated by the presence of bands corresponding to the vibration of aromatic rings and aliphatic C-C and C-O stretching at 1336 and 1567 cm-1, respectively. FTIR confirmed the presence of peaks corresponding to PDA and BC in the BC/PDA hydrogel scaffolds at 3673, 3348, 2900, and 1052 cm-1, indicating the successful interaction of PDA with BC nanofibers, which was further corroborated by the SEM images. The tensile strength, swelling ratio, degradation, and surface wettability characteristics of the composite BC biomaterials were also investigated. The BC/PDA hydrogels with PDA-functionalized BC nanofibers demonstrated excellent tensile strength and water-wetting ability while maintaining the stability of the BC fibers. The enhanced cytocompatibility of the BC/PDA hydrogels was studied using the PrestoBlue assay. Culturing murine NIH/3T3 fibroblasts on BC/PDA hydrogels showed higher metabolic activity and enhanced proliferation. Additionally, it improved cell viability when using BC/PDA hydrogels. Thus, these BC/PDA composite biomaterials can be used as biocompatible natural alternatives to synthetic substitutes for skin tissue engineering and wound-dressing applications.