Advances in porphyrins and chlorins associated with polysaccharides and polysaccharides-based materials for biomedical and pharmaceutical applications

Over the last decade, the convergence of advanced materials and innovative applications has fostered notable scientific progress within the biomedical and pharmaceutical fields. Porphyrins and their derivatives, distinguished by an extended conjugated π-electron system, have a relevant role in propelling these advancements, especially in drug delivery systems, photodynamic therapy, wound healing, and (bio)sensing. However, despite their promise, the practical clinical application of these macrocycles is hindered by their inherent challenges of low solubility and instability under physiological conditions. To address this limitation, researchers have exploited the synergistic association of porphyrins and chlorins with polysaccharides by engineering conjugated systems and composite/hybrid materials. This review compiles the principal advances in this growing research field, elucidating fundamental principles and critically examining the applications of such materials within biomedical and pharmaceutical contexts. Additionally, the review addresses the eventual challenges and outlines future perspectives for this poignant research field. It is expected that this review will serve as a comprehensive guide for students and researchers dedicated to exploring state-of-the-art materials for contemporary medicine and pharmaceutical applications.

Stimulus-responsive luminescent hydrogels: Design and applications

Luminescent hydrogels are emerging soft materials with applications in photoelectric, biomedicine, sensors and actuators, which are fabricated via covalently conjugation of luminophors to hydrogelators or physical loading of luminescent organic/inorganic materials into hydrogel matrices. Due to the intrinsic stimulus-responsiveness for hydrogels such as thermo-, pH, ionic strength, light and redox, luminescent hydrogels could respond to external physical or chemical stimuli through varying the luminescent properties such as colors, fluorescent intensity and so on, affording diverse application potential in addition to the pristine individual hydrogels or luminescent materials. Based on the rapid development of such area, here we systematically summarize and discuss the design protocols, properties as well as the applications of stimulus-responsive luminescent hydrogels. Because of the stimuli-responsiveness, biocompatibility, injectable and controllability of luminescent hydrogels, they are widely used as functional smart materials. We illustrate the applications of luminescent hydrogels. The future developments about luminescent hydrogels are also presented.

Thermosensitive porphyrin-incorporated hydrogel with four-arm PEG-PCL copolymer (II): doxorubicin loaded hydrogel as a dual fluorescent drug delivery system for simultaneous imaging tracking in vivo

Visualization of a drug delivery system could reveal the pharmacokinetic properties, which is essential for the design of a novel drug delivery system. In vivo optical imaging offers an advanced tool to monitor the drug release process and the therapeutic effect by the combination of fluorescence imaging and bioluminescence imaging. Multispectral fluorescence imaging can separate the drug and the carrier without interference. Herein, a dual fluorescent anti-tumor drug delivery system was monitored with the doxorubicin-loaded hydrogel to further explore the application of the porphyrin-incorporated hydrogel with four-arm PEG-PCL copolymer as a drug carrier, based on the beneficial fluorescence and good biocompatibility of the porphyrin incorporated hydrogel. Using nude mice bearing luciferase expressed hepatic tumor as models, the whole process from the drug delivery to the tumor therapeutic effects were real time visualized simultaneously after administration at interval from 0 to 18 d. The imaging results suggest that the fluorescence signals of the drug and the carrier can be separated and unmixed from the drug-loaded hydrogel successfully, avoiding the interference of the fluorescence signals. The tumor growth or inhibition can be real time tracked and analyzed quantitatively by bioluminescence imaging. Noninvasive continuous tracking the in vivo drug delivery process simultaneously is a potential trend for the precise drug delivery and treatment.

Enhanced green fluorescence protein/layered double hydroxide composite ultrathin films: bio-hybrid assembly and potential application as a fluorescent biosensor

Protein immobilization is of significant interest for applications in biosensing, drug delivery and bioconversion, and challenges still remain for the in vitro immobilization and application of proteins. Due to it being non-specific to species, easy to express in cells and able to exhibit fluorescence after expression without the need for cofactors or chaperones, green fluorescent protein (GFP), together with its differently colored mutants, has been widely studied and applied. This article reports the fabrication of enhanced green fluorescent protein (EGFP)/layered double hydroxide nanosheet (EGFP/LDH)_n ultrathin films (UTFs) via a layer-by-layer assembly technique based on electrostatic and hydrogen-bond interactions, and this realized the immobilization of EGFP. The obtained UTFs show a long-range-ordered periodic layered stacking structure and strong fluorescence originating from EGFP, which also retains its predominant β-barrel structure well in the LDH laminates. The inorganic LDH laminates play an important role in protecting and improving the structure and properties of the EGFP in the UTFs. Furthermore, the UTFs exhibit a reversible fluorescence response between different pH environments or different wet or dry environments, and also could detect some small biological medicine molecules such as protoporphyrin, and thus they have the potential to be a novel type of biological fluorescence sensor.

Assembly of neutral conjugated polymers with layered double hydroxide nanosheets by the layer-by-layer method

This article reports that the neutral conjugated polymers (NCPs) can also be assembled with exfoliated MgAl-layered double hydroxide (LDH) nanosheets to form the ordered inorganic/organic hybrid ultrathin films via the LbL assembly technique.

Synthesis and biomedical applications of fluorescent nanogels

Fluorescent nanogel is an innovative biomedical material with hydroscopicity, degradability, and responsiveness.

Synthesis and characterization of PLGA nanoparticle/4-arm-PEG hybrid hydrogels with controlled porous structures

Here, we constructed PLGA NP crosslinked 4-arm-PEG hybrid hydrogels with adjustable porous structures, surface properties and mechanical properties.

Functional biomedical hydrogels for in vivo imaging

In vivo imaging of biomedical hydrogels enables real-time and non-invasive visualization of the status of structure and function of hydrogels.