Investigation of the antibacterial properties of hyaluronic acid microneedles based on chitosan and MoS2

Nanomaterials-incorporated polymeric microneedles for wound healing applications

There is a growing and urgent need for developing novel biomaterials and therapeutic approaches for efficient wound healing. Microneedles (MNs), which can penetrate necrotic tissues and biofilm barriers at the wound and deliver active ingredients to the deeper layers in a minimally invasive and painless manner, have stimulated the interests of many researchers in the wound-healing filed. Among various materials, polymeric MNs have received widespread attention due to their abundant material sources, simple and inexpensive manufacturing methods, excellent biocompatibility and adjustable mechanical strength. Meanwhile, due to the unique properties of nanomaterials, the incorporation of nanomaterials can further extend the application range of polymeric MNs to facilitate on-demand drug release and activate specific therapeutic effects in combination with other therapies. In this review, we firstly introduce the current status and challenges of wound healing, and then outline the advantages and classification of MNs. Next, we focus on the manufacturing methods of polymeric MNs and the different raw materials used for their production. Furthermore, we give a summary of polymeric MNs incorporated with several common nanomaterials for chronic wounds healing. Finally, we discuss the several challenges and future prospects of transdermal drug delivery systems using nanomaterials-based polymeric MNs in wound treatment application.

Porous reticular Co@Fe metal-organic gel: dual-function simulated peroxidase nanozyme for both colorimetric sensing and antibacterial applications

Constructing metal-organic gels (MOGs) with enzyme-catalyzed activity and studying their catalytic mechanism are crucial for the development of novel nanozyme materials. In this study, a Co@Fe MOG with excellent peroxidase activity was developed by a simple and mild one-pot process. The results showed that the material exhibited almost a single peroxidase activity under optimal pH conditions, which allowed it to attract and oxidize the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB). Based on the active electron transfer between the metal centers and the organic ligand in the synthetic material, the Co@Fe MOG-H2O2-TMB system was verified to be able to detect H2O2 and citric acid (CA). The catalytic microenvironment formed by the adsorption and the catalytic center accelerated the electron-transfer rate, which expedited the generation of hydroxyl radicals (˙OH, a kind of reactive oxygen species (ROS)) in the presence of H2O2. The persistence and high intensity of ˙OH generation were proven, which would endow Co@Fe MOG with a certain antibacterial ability, promoting the healing of bacteria-infected wounds. In conclusion, this study contributes to the development efforts toward the application systems of nanozymes for marker detection and antibacterial activity.

Unravelling the role of microneedles in drug delivery: Principle, perspectives, and practices

In recent year, the research of transdermal drug delivery systems has got substantial attention towards the development of microneedles (MNs). This shift has occurred due to multifaceted advantages of MNs as they can be utilized to deliver the drug deeper to the skin with minimal invasion, offer successful delivery of drugs and biomolecules that are susceptible to degradation in gastrointestinal tract (GIT), act as biosensors, and help in monitoring the level of biomarkers in the body. These can be fabricated into different types based on their applications as well as material for fabrication. Some of their types include solid MNs, hollow MNs, coated MNs, hydrogel forming MNs, and dissolving MNs. These MNs deliver the therapeutics via microchannels deeper into the skin. The coated and hollow MNs have been found successful. However, they suffer from poor drug loading and blocking of pores. In contrast, dissolving MNs offer high drug loading. These MNs have also been utilized to deliver vaccines and biologicals. They have also been used in cosmetics. The current review covers the different types of MNs, materials used in their fabrication, properties of MNs, and various case studies related to their role in delivering therapeutics, monitoring level of biomarkers/hormones in body such as insulin. Various patents and clinical trials related to MNs are also covered. Covered are the major bottlenecks associated with their clinical translation and potential future perspectives.

Microneedles Based on a Biodegradable Polymer-Hyaluronic Acid

Transdermal transport can be challenging due to the difficulty in diffusing active substances through the outermost layer of the epidermis, as the primary function of the skin is to protect against the entry of exogenous compounds into the body. In addition, penetration of the epidermis for substances hydrophilic in nature and particles larger than 500 Da is highly limited due to the physiological properties and non-polar nature of its outermost layer, namely the stratum corneum. A solution to this problem can be the use of microneedles, which "bypass" the problematic epidermal layer by dispensing the active substance directly into the deeper layers of the skin. Microneedles can be obtained with various materials and come in different types. Of special interest are carriers based on biodegradable and biocompatible polymers, such as polysaccharides. Therefore, this paper reviews the latest literature on methods to obtain hyaluronic acid-based microneedles. It focuses on the current advancements in this field and consequently provides an opportunity to guide future research in this area.

Recent Advances in Two-Dimensional Nanomaterials for Healthcare Monitoring

The development of advanced technologies for the fabrication of functional nanomaterials, nanostructures, and devices has facilitated the development of biosensors for analyses. Two-dimensional (2D) nanomaterials, with unique hierarchical structures, a high surface area, and the ability to be functionalized for target detection at the surface, exhibit high potential for biosensing applications. The electronic properties, mechanical flexibility, and optical, electrochemical, and physical properties of 2D nanomaterials can be easily modulated, enabling the construction of biosensing platforms for the detection of various analytes with targeted recognition, sensitivity, and selectivity. This review provides an overview of the recent advances in 2D nanomaterials and nanostructures used for biosensor and wearable-sensor development for healthcare and health-monitoring applications. Finally, the advantages of 2D-nanomaterial-based devices and several challenges in their optimal operation have been discussed to facilitate the development of smart high-performance biosensors in the future.

Preparation and Physicochemical Characterization of Hyaluronic Acid-Lysine Nanogels Containing Serratiopeptidase to Control Biofilm Formation

Remarkable resistance of bacterial biofilms to high doses of antimicrobials and antibiotics is one of their main challenges. Encapsulation of proteolytic enzymes is one of the suggested strategies to tackle this problem. In this regard, the antibacterial and anti-biofilm activity of biocompatible hyaluronic acid- Lysine nanogels containing serratiopeptidase (SRP-loaded HA-Lys nanogel) was assessed against P. aeruginosa and S. aureus strains. SRP-loaded HA-Lys nanogel was prepared using dropping method and optimized by Box-Behnken experimental design. These formulations were studied for physical characterization, release profile, stability, bioactivity, and anti-biofilm effects. The particle size, polydispersity index (PDI), and surface charge were measured by Zetasizer Nano ZS. The average particle size and zeta potential of the optimum sample were 156 nm and -14.1 mV, respectively. SRP release showed an initial burst followed by sustained release and the highest release was around 77%. Enzyme biological activity data revealed the higher efficiency of free SRP compared to SRP-loaded HA-Lys nanogel. The time-kill assay showed that both forms of SRP-loaded HA-Lys nanogel and blank HA-Lys nanogel showed significant antimicrobial activity against examined bacteria in comparison to the free enzyme. The obtained results demonstrated improved anti-biofilm efficacy and down regulation of tested biofilm genes for both SRP-loaded HA-Lys nanogel 100% and blank HA-Lys nanogel 100% compared to SRP 100%.

A multimodal therapy for infected diabetic wounds based on glucose-responsive nanocomposite-integrated microneedles

Diabetic wounds in a state of high glucose are refractory to treatment and healing, especially if they are infected with bacteria. Herein, a novel nanocomposite (CIP/GOx@ZIF-8) was synthesized by loading ciprofloxacin hydrochloride (CIP) and glucose oxidase (GOx) into zeolitic imidazole framework-8 (ZIF-8) that exhibited good glucose sensitivity and catalytic activity. The high glucose in diabetic wounds could be decomposed into hydrogen peroxide (H2O2) and gluconic acid via the catalysis of GOx, which further destroyed CIP/GOx@ZIF-8 to release Zn2+ and cargos. The combination of glucose starvation, Zn2+, H2O2 and CIP could elevate the antibacterial effect and reduce bacterial resistance. Subsequently, the nanocomposite was fabricated into dissolving microneedles (CIP/GOx@ZIF-8 MNs) using polyvinylpyrrolidone (PVP). The microneedles exhibited good mechanical strength, puncture performance, dissolving performance, glucose responsiveness, antibacterial performance and biocompatibility. For in vivo wound healing, CIP/GOx@ZIF-8 MNs with good biosafety facilitated neovascularization and collagen deposition as well as reduced inflammation, and the wounds were almost healed after treatment. This multimodal therapeutic strategy is created to provide a unique treatment for infected diabetic wounds.