A self-healing smart photonic crystal hydrogel sensor for glucose and related saccharides

Smart self-healing hydrogel wound dressings for diabetic wound treatment

Diabetic wounds are difficult to treat clinically because they heal poorly, often leading to severe complications such as infections and amputations. Hydrogels with smart self-healing properties show great promise for treating diabetic wounds. These hydrogels are capable of continuously and dynamically responding to changes in the wound environment, feature improved mechanical qualities and the capacity to self-heal damage. We explore the latest developments in smart self-healing hydrogels for diabetic wound healing in this review. First, we systematically summarize the obstacles in treating diabetic wounds. We then highlighted the significance of smart self-healing hydrogels, explaining their stimulus-responsive mechanisms and self-healing design approaches, along with their applications in addressing these challenges. Finally, we discussed the unresolved obstacles and potential avenues for future research. We anticipate that this review will facilitate the continued refinement of smart self-healing hydrogels for diabetic wound dressings, aiming for broader clinical adoption.

Molecularly imprinted 2D photonic crystal hydrogel sensor for sodium dichloroisocyanurate

Sodium dichloroisocyanurate (SDIC) is an efficient, safe and convenient halogen disinfectant that is widely used for hospital, tableware and swimming pool disinfection. In order to ensure its effective use and safety, especially in clinical settings, effective identification methods are necessary. The effective chlorine content is one of the quality standards for chlorine-containing disinfectants, but its complex experimental operation as well as poor specificity and portability limit its application. In contrast, testing based on molecularly imprinted photonic crystal sensors provides excellent performance. Therefore, it is of great significance to establish a new and simple SDIC recognition method. We prepared a novel molecularly imprinted two-dimensional (2D) photonic crystal hydrogel (MIPH) for sensitive and label-free recognition of SDIC. The response performance of the resultant MIPH sensor was determined by monitoring particle spacing changes in the polystyrene (PS) 2D photonic crystals embedded in the hydrogel. Particle spacing changes were recorded by measuring changes in the diameter of the Debye diffraction ring of the MIPH sensor. As the concentration of SDIC in solution increased from 1 × 10-2 to 1.0 mmol L-1, the diameter of the Debye diffraction ring increased by 6 mm, and the corresponding photonic crystal particle spacing decreased by 56 nm. The particle spacing changes in the MIPH sensor showed a linear relationship with the SDIC concentration in the range of 1 × 10-2-1.0 mmol L-1, and the limit of detection (S/N = 3) was found to be 3 × 10-3 mmol L-1. The constructed hydrogel sensor was successfully used to detect SDIC in sodium dichloroisocyanurate disinfectant powder, demonstrating recoveries of 96-100% and RSD of 7.2-7.6%. Our molecularly imprinted SDIC photonic crystal hydrogel provides a universal strategy for designing sensors for other clinical disinfectants.

Hydrogel for light delivery in biomedical applications

Traditional optical waveguides or mediums are often silica-based materials, but their applications in biomedicine and healthcare are limited due to the poor biocompatibility and unsuitable mechanical properties. In term of the applications in human body, a biocompatible hydrogel system with excellent optical transparency and mechanical flexibility could be beneficial. In this review, we explore the different designs of hydrogel-based optical waveguides derived from natural and synthetic sources. We highlighted key developments such as light emitting contact lenses, implantable optical fibres, biosensing systems, luminating and fluorescent materials. Finally, we expand further on the challenges and perspectives for hydrogel waveguides to achieve clinical applications.

Dual Dynamic Covalently Crosslinked Alginate Hydrogels with Tunable Properties and Multiple Stimuli-Responsiveness

Alginate is a biopolymer that can be crosslinked with calcium ions to fabricate cytocompatible hydrogels. However, using calcium ions to crosslink alginate provides limited properties and functions to alginate hydrogels, restricting their biomedical applications. Here, phenylboronic acid-functionalized polyethyleneimine (PBA-PEI) was developed to introduce two orthogonal dynamic covalent crosslinks in the alginate hydrogels, where PBA-PEI was used to crosslink alginate dialdehyde (ADA) through imine bonds and boronate ester bonds. The grafting degree of PBA in the PEI structure was applied to fine-tune the properties of PBA-PEI/ADA hydrogels, including the rheological property, mechanical strength, swelling behavior, and antibacterial activity. In particular, the highly sensitive boronate ester bonds in the network enabled PBA-PEI/ADA hydrogels to be responsive to several stimuli, such as glucose, fructose, and hydrogen peroxide. Taken together, PBA-PEI/ADA hydrogels with tunable properties and multiple stimuli-responsiveness have been demonstrated as smart biomaterials for advanced biomedical applications.