The design of effective treatments for critical size bone defects, which result from various conditions such as trauma, infection, injury, or tumor resection, presents a significant challenge in clinical practice. While autologous grafts are commonly regarded as gold standard treatments in these complex healing scenarios, they are often associated with notable limitations, including donor site morbidity and limited graft volume. As a result, recent research trends have shifted towards developing biomaterials that better emulate the inherent complexity of the native bone structure and function through implementation of a “Diamond Concept” polytherapy strategy. Central to this approach is the utilization of biomaterials, increasingly composed of composite materials that integrate bioactive osteoinductive factors and cell sources to enhance healing outcomes. The usage of Wnt signaling specific agonists as osteoinductive mediators has been recently shown to be a promising strategy for promoting healing, as this pathway is well established to have an important role in both osteogenic differentiation and bone formation processes. Implementation of a localized delivery system through scaffold incorporation is necessary in this scenario, however, to minimize any potential off-target effects caused by the Wnt signaling cascade’s non-specificity to bone. Findings in the literature clearly show that this approach holds promise to improve clinical healing outcomes, paving the way for more effective treatment options. In this review, we will generally discuss the design of biomaterials, specifically bulk materials and composites, for the treatment of critical size bone defects. Additionally, we will highlight recent work on the design of chitosan-based scaffolds modified with purine crosslinking, to overcome cytotoxicity issues associated with other chemical crosslinkers. In this context, we focus on optimizing material design for this bone healing application and discuss the benefits of localized Wnt agonist as mediators to improve the scaffold’s osteoinductive behavior.

Silver iodide (AgI) nanostructures have been considered as promising candidates for optical biosensors owing to their optical characteristics of optical properties, including tunable surface plasmon resonance (SPR) and fluorescence enhancement. Such properties let one analyze biomolecules with high sensitivity, which makes them ultra-useful in diagnostics. The formed AgI nanostructures can be synthesized using chemical precipitation and template methods that enable fine-tuning of the morphology and crystallinity of the final nanostructure. The presence of SPR enhances optical signals potentially, and fluorescence enhancement helps visualize biomolecule interactions easier as the analyte concentration is usually low. Such uses of biosensors include applications in proteins, nucleic acids, and other biomolecules for progress in disease diagnosis and pharmacogenomics. Moreover, the good biocompatibility level of the created AgI nanostructures makes it possible to integrate them into biological systems safely, increasing their usage in medicine. This integration of their appealing optics, biosensing operating principles, and biocompatibility establishes their centrality in the creation of future photonic biosensors for faster, intuitive, and painless detection.

Nanoparticles (NPs) are at the forefront as they are providing unprecedented solutions to obstacles and issues in treating neurodegenerative diseases. Due to their size, surface characteristics, and ability to be functionalized, these carriers can directly deliver therapeutics across what is considered one of the main barriers to central nervous system (CNS) treatment, the blood-brain barrier (BBB). Through nano-technology, anti-disease agents such as Alzheimer’s, Parkinson’s, and Huntington’s therapies become more bioavailable, specific in action, and with fewer side effects. The NPs serve as molecular carriers that facilitate transport across the BBB by receptor-mediated transcytosis or by disruption of the barrier with a view to properly delivering drugs to the neural tissues. Some of the therapeutic applications of nanotechnology also present the concept of molecular medicine since the NPs are designed to deliver drugs in accordance with specific biomolecule signals. Besides the therapeutic applications, NPs replace the traditional contrast media for magnetic resonance imaging (MRI) and positron emission tomography (PET) scans for better diagnosis as well as disease tracking in the early stages. In addition, their effects on solubility increase the therapeutic potential of earlier useless compounds, and the preservation of bioactive molecules from degradation increases the therapeutic capacity of medications. Neurodegenerative disorders are marked by oxidative stress and inflammation that contribute to the disease severity; thus, liposomes, dendrimers, and polymeric NPs encapsulate antioxidants and anti-inflammatory compounds, so they target the areas most affected by the disease. Such sophisticated systems minimize the extension of neuronal deterioration and enhance the lot of such patients. The “theranostic” NPs allow for continuous diagnosis and treatment by containing both diagnostic and therapeutic features. These have created unprecedented opportunities to meet the unmet needs in CNS disorders and may revolutionize the evolution of managing neurodegenerative diseases and innovative neuroimaging procedures in the future.