Advancements and applications of upconversion nanoparticles in wound dressings.

Wound healing is a complex process that requires effective management to prevent infections and promote efficient tissue regeneration. In recent years, upconversion nanoparticles (UCNPs) have emerged as promising materials for wound dressing applications due to their unique optical properties and potential therapeutic functionalities. These nanoparticles possess enhanced antibacterial properties when functionalized with antibacterial agents, helping to prevent infections, a common complication in wound healing. They can serve as carriers for controlled drug delivery, enabling targeted release of therapeutic agents to the wound site, allowing for tailored treatment and optimal healing conditions. These nanoparticles possess the ability to convert near-infrared (NIR) light into the visible and/or ultraviolet (UV) regions, making them suitable for therapeutic (photothermal therapy and photodynamic therapy) and diagnostic applications. In the context of wound healing, these nanoparticles can be combined with other materials such as hydrogels, fibers, metal-organic frameworks (MOFs), graphene oxide, etc., to enhance the healing process and prevent the growth of microbial infections. Notably, UCNPs can act as sensors for real-time monitoring of the wound healing progress, providing valuable feedback to healthcare professionals. Despite their potential, the use of UCNPs in wound dressing applications faces several challenges. Ensuring the stability and biocompatibility of UCNPs under physiological conditions is crucial for their effective integration into dressings. Comprehensive safety and efficacy evaluations are necessary to understand potential risks and optimize UCNP-based dressings. Scalability and cost-effectiveness of UCNP synthesis and manufacturing processes are important considerations for practical applications. In addition, efficient incorporation of UCNPs into dressings, achieving uniform distribution, poses an important challenge that needs to be addressed. Future research should prioritize addressing concerns regarding stability and biocompatibility, efficient integration into dressings, rigorous safety evaluation, scalability, and cost-effectiveness. The purpose of this review is to critically evaluate the advantages, challenges, and key properties of UCNPs in wound dressing applications to provide insights into their potential as innovative solutions for enhancing wound healing outcomes. We have provided a detailed description of various types of smart wound dressings, focusing on the synthesis and biomedical applications of UCNPs, specifically their utilization in different types of wound dressings.

Combination therapy using nanomaterials and stem cells to treat spinal cord injuries.

As a part of the central nervous system, the spinal cord (SC) provides most of the communications between the brain and other parts of the body. Any damage to SC interrupts this communication, leading to serious problems, which may remain for the rest of their life. Due to its significant impact on patients' quality of life and its exorbitant medical costs, SC injury (SCI) is known as one of the most challengeable diseases in the world. Thus, it is critical to introduce highly translatable therapeutic platforms for SCI treatment. So far, different strategies have been introduced, among which utilizing various types of stem cells is one of the most interesting ones. The capability of stem cells to differentiate into several types of cell lines makes them promising candidates for the regeneration of injured tissues. One of the other interesting and novel strategies for SCI treatment is the application of nanomaterials, which could appear as a carrier for therapeutic agents or as a platform for culturing the cells. Combining these two approaches, stem cells and nanomaterials, could provide promising therapeutic strategies for SCI management. Accordingly, in this review we have summarized some of the recent advancements in which the applications of different types of stem cells and nanomaterials, alone and in combination forms, were evaluated for SCI treatment.

Selection of natural biomaterials for micro-tissue and organ-on-chip models.

The desired organ in micro-tissue models of organ-on-a-chip (OoC) devices dictates the optimum biomaterials, divided into natural and synthetic biomaterials. They can resemble biological tissues' biological functions and architectures by constructing bioactivity of macromolecules, cells, nanoparticles, and other biological agents. The inclusion of such components in OoCs allows them having biological processes, such as basic biorecognition, enzymatic cleavage, and regulated drug release. In this report, we review natural-based biomaterials that are used in OoCs and their main characteristics. We address the preparation, modification, and characterization methods of natural-based biomaterials and summarize recent reports on their applications in the design and fabrication of micro-tissue models. This article will help bioengineers select the proper biomaterials based on developing new technologies to meet clinical expectations and improve patient outcomes fusing disease modeling.

Development of mucoadhesive modified kappa-carrageenan/pectin patches for controlled delivery of drug in the buccal cavity.

In this study, modified kappa-carrageenan/pectin hydrogel patches were fabricated for treatment of buccal fungal infections. For this purpose, kappa-carrageenan-g-acrylic acid was modified with different thiolated agents (L-cysteine and 3-mercaptopropionic acid), and the thiol content of the resulting modified kappa-carrageenan was confirmed by elemental analyzer. Then, the hydrogel patches were fabricated, and characterized by Fourier-transform infrared spectroscopy, thermogravimetric analysis, ex vivo mucoadhesion test, and swelling behavior. Triamcinolone acetonide was added either directly or by encapsulating within the poly(lactic-co-glycolic acid) nanoparticles. The release amount of the drug from the directly loaded patch was 7.81 mg/g polymer, while it was 3.28 mg/g polymer for the encapsulated patch with the same content at 7 hr. The hydrogel patches had no cytotoxicity by cell culture studies. Finally, the drug loaded hydrogel patches were demonstrated antifungal activity against Aspergillus fumigatus and Aspergillus flavus. These results provide that the novel modified kappa-carrageenan and pectin based buccal delivery system has promising antifungal property, and could have advantages compared to conventional buccal delivery systems.

Tissue Adhesives: From Research to Clinical Translation.

Sutures, staples, clips and skin closure strips are used as the gold standard to close wounds after an injury. In spite of being the present standard of care, the utilization of these conventional methods is precarious amid complicated and sensitive surgeries such as vascular anastomosis, ocular surgeries, nerve repair, or due to the high-risk components included. Tissue adhesives function as an interface to connect the surfaces of wound edges and prevent them from separation. They are fluid or semi-fluid mixtures that can be easily used to seal any wound of any morphology - uniform or irregular. As such, they provide alternatives to new and novel platforms for wound closure methods. In this review, we offer a background on the improvement of distinctive tissue adhesives focusing on the chemistry of some of these products that have been a commercial success from the clinical application perspective. This review is aimed to provide a guide toward innovation of tissue bioadhesive materials and their associated biomedical applications.

Advancements and future directions in the antibacterial wound dressings - A review.

Wound repair is a complex process that has not been entirely understood. It can conclude in several irregularities. Hence, designing an appropriate wound dressing that can accelerate the healing period is critical. Infections, a major obstacle to wound repair, cause an elevated inflammatory responses and result in ultimate outcome of incomplete and prolonged wound repair. To overcome these shortcomings, there is a growing requirement for antibacterial wound dressings. Dressings with antibacterial activities and multifunctional behaviors are highly anticipated to avoid the wound infection for successful healing. The aim of this review is not only to concentrate on the importance of antibacterial dressings for wound healing applications but also to discuss recent studies and some future perspectives about antibacterial wound dressings.

Doxorubicin hydrochloride loaded nanotextured films as a novel drug delivery platform for ovarian cancer treatment.

An approach for cancer treatment is modulation of tumor microenvironment. Based on the role of extracellular matrix in cell modulation, fabrication of textured materials mimicking extracellular matrix could provide novel opportunities such as determining cancer cell behaviour. With this background, in this work, we have fabricated doxorubicin hydrochloride loaded nanotextured films which promote topographical attachment of cancer cells to film surface, and eliminate cells by release of the anti-cancer drug encapsulated within the films. These films are designed to be placed during surgical removal of the tumor with the intent to prevent ovarian cancer recurrence by capturing cancer cell residuals. With this aim, hemispherical protrusion shaped surface textures were acquired using colloidal lithography technique using 280 nm, 210 nm or 99 nm polystyrene particles. Once moulds were formed, nanotextured films were obtained by casting water-in-oil stable polycaprolactone emulsions encapsulating doxorubicin hydrochloride. Films were then characterized, and evaluated as drug delivery systems. According to results, we found that template morphologies were successfully transferred to films by atomic force microscopy studies. Hydrophilic surfaces were formed with contact angle values around 40°. In-vitro drug release studies indicated that nanotextured films best fit into the Higuchi model, and ∼30% of the drug is released from the films within 60 days. Cell culture results indicated increases in the attachment and viability of human ovarian cancer cells to nanotextured surfaces, particularly to the film fabricated using 99 nm particles. Our results demonstrated that delivery of anti-cancer drugs by use of nanotextured materials could be efficient in cancer therapy, and may offer new possibilities for cancer treatment.

The interactions of human ovarian cancer cells and nanotextured surfaces: cell attachment, viability and apoptosis studies.

Understanding cell responses to the topography they are interacting with has a key role in designing surfaces due to the distinctiveness in the responses of different cell types. Thus far, a variety of surface textures have been fabricated, and the cellular responses of diversified cell lines to the surface textures have been assessed together with surface chemistry. However, the results reported in the literature are contradictory, and also not in-depth for inferring the relevance between cells, surface chemistry, and surface topography. Starting from this point of view, we focused on fabricating surfaces having extracellular matrix-like surface patterns and investigated the influence of patterning on human ovarian cancer cells. In this study, hemispherical protrusion-shaped, nanotextured surfaces were prepared via colloidal lithography and polymer casting methods using monolayer templates prepared from 280 nm, 210 nm, and 99 nm polystyrene particles and polydimethylsiloxane moulds. Then, the surface textures were transferred to biocompatible polycaprolactone films. After the characterisation of the surfaces via atomic force microscopy, X-ray photoelectron spectroscopy, and contact angle measurements, the cellular response to topography was evaluated by cell attachment, viability, and apoptosis studies. The results were compared with non-textured surfaces and control plate wells. The results showed that human ovarian cancer cell attachment increased with nanotexturing, which suggests that nanotexturing may be a promising approach for cancer cell modulation, and may have the potential to introduce new strategies for cancer treatment.

Current Strategies and Future Perspectives of Skin-on-a-Chip Platforms: Innovations, Technical Challenges and Commercial Outlook.

The skin is the largest and most exposed organ in the human body. Not only it is involved in numerous biological processes essential for life but also it represents a significant endpoint for the application of pharmaceuticals. The area of in vitro skin tissue engineering has been progressing extensively in recent years. Advanced in vitro human skin models strongly impact the discovery of new drugs thanks to the enhanced screening efficiency and reliability. Nowadays, animal models are largely employed at the preclinical stage of new pharmaceutical compounds development for both risk assessment evaluation and pharmacokinetic studies. On the other hand, animal models often insufficiently foresee the human reaction due to the variations in skin immunity and physiology. Skin-on-chips devices offer innovative and state-of-the-art platforms essential to overcome these limitations. In the present review, we focus on the contribution of skin-on-chip platforms in fundamental research and applied medical research. In addition, we also highlighted the technical and practical difficulties that must be overcome to enhance skin-on-chip platforms, e.g. embedding electrical measurements, for improved modeling of human diseases as well as of new drug discovery and development.

The influence of nanotexturing of poly(lactic-co-glycolic acid) films upon human ovarian cancer cell attachment.

In this study, we have produced nanotextured poly(lactic-co-glycolic acid) (PLGA) films by using polystyrene (PS) particles as a template to make a polydimethylsiloxane mould against which PLGA is solvent cast. Biocompatible, biodegradable and nanotextured PLGA films were prepared with PS particles of diameter of 57, 99, 210, and 280 nm that produced domes of the same dimension in the PLGA surface. The effect of the particulate monolayer templating method was investigated to enable preparation of the films with uniformly ordered surface nanodomes. Cell attachment of a human ovarian cancer cell line (OVCAR3) alone and co-cultured with mesenchymal stem cells (MSCs) was evaluated on flat and topographically nano-patterned surfaces. Cell numbers were observed to increase on the nanotextured surfaces compared to non-textured surfaces both with OVCAR3 cultures and OVCAR3-MSC co-cultures at 24 and 48 h time points.

Multi-modal switching in responsive DNA block co-polymer conjugates.

New classes of information-rich DNA block co-polymer conjugates were synthesised, encoded with thermoresponsive and biocompatible poly(tri(ethylene glycol)ethyl ether methacrylate) (pTriEGMA) chains and oligomeric nucleic acids connected by either bioreducible or non-reducible links. The pTriEGMA chains were grown from initiator-functionalised hybridised DNA, designed to assemble with toehold overhangs. Functional information in the conjugates was explored via dynamic light scattering (DLS) and atomic force microscopy (AFM), in order to evaluate (i) reversible self-assembly into supramolecular structures across the pTriEGMA phase transition temperature; (ii) conformational change via addition of competing DNA sequences across the toeholds, and (iii) reductive cleavage of polymer-DNA links. The results showed that discrete nanoscale conjugates could reversibly associate through pTriEGMA phase behaviour and that size and association behaviour in one class of conjugate could be switched by addition of a competing DNA sequence and by reduction to break the polymer-DNA links. Preliminary experiments with the DNA-conjugates as delivery systems for doxorubicin to a cancer cell line indicated good tolerability of the conjugates alone and cytotoxic efficacy when loaded with the drug.