Graphene-laden hydrogels: A strategy for thermally triggered drug delivery

Novel Photothermal Graphene-Based Hydrogels in Biomedical Applications

In the last decade, photothermal therapy (PTT) has attracted tremendous attention because it is non-invasive, shows high efficiency and antibacterial activity, and minimizes drug side effects. Previous studies demonstrated that PTT can effectively inhibit the growth of bacteria and promotes cell proliferation, accelerating wound healing and tissue regeneration. Among different NIR-responsive biomaterials, graphene-based hydrogels with photothermal properties are considered as the best candidates for biomedical applications, due to their excellent properties. This review summarizes the current advances in the development of innovative graphene-based hydrogels for PTT-based biomedical applications. Also, the information about photothermal properties and the potential applications of graphene-based hydrogels in biomedical therapies are provided. These findings provide a great potential for supporting their applications in photothermal biomedicine.

A high loading nanocarrier for the 5-fluorouracil anticancer drug based on chloromethylated graphene

In the present work, we report a facile and simple strategy to functionalize graphene with the chloromethyl (CH2Cl) functional group as a nanoplatform for effectual loading of the 5-fluorouracil (5-FU) anticancer drug. To achieve the highest loading capacity, hydrochloric acid concentration, the quantity of paraformaldehyde, ultrasonic treatment time, and stirring duration were all carefully optimized. The results revealed that the optimum conditions for functionalizing graphene were obtained at 70 mL of hydrochloric acid, 700 mg of paraformaldehyde, and times of 35 min and 2 h of ultrasonication and stirring. Later, the drug (5-FU) was loaded onto CH2Cl-functionalized graphene through hydrogen bonding and π-π interactions. The chemical structure of the functionalized material and the loading of the 5-FU drug were confirmed by FTIR analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy. The 5-FU loading capacity of as-prepared materials was determined using the ion chromatography instrument. Our findings demonstrate that chloromethylated graphene is a very excellent nano-platform for high-efficiency drug loading, yielding a loading capacity of 52.3%, comparatively higher than pure graphene (36.54%).

Antimicrobial Hydrogels: Potential Materials for Medical Application

Microbial infections based on drug-resistant pathogenic organisms following surgery or trauma and uncontrolled bleeding are the main causes of increased mortality from trauma worldwide. The prevalence of drug-resistant pathogens has led to a significant increase in medical costs and poses a great threat to the normal life of people. This is an important issue in the field of biomedicine, and the emergence of new antimicrobial materials hydrogels holds great promise for solving this problem. Hydrogel is an important material with good biocompatibility, water absorption, oxygen permeability, adhesion, degradation, self-healing, corrosion resistance, and controlled release of drugs as well as structural diversity. Bacteria-disturbing hydrogels have important applications in the direction of surgical treatment, wound dressing, medical device coating, and tissue engineering. This paper reviews the classification of antimicrobial hydrogels, the current status of research, and the potential of antimicrobial hydrogels for one application in biomedicine, and analyzes the current research of hydrogels in biomedical applications from five aspects: metal-loaded hydrogels, drug-loaded hydrogels, carbon-material-loaded hydrogels, hydrogels with fixed antimicrobial activity and biological antimicrobial hydrogels, and provides an outlook on the high antimicrobial activity, biodegradability, biocompatibility, injectability, clinical applicability and future development prospects of hydrogels in this field.

Enhanced Stability of Dopamine Delivery via Hydrogel with Integrated Graphene

The synthesis of graphene-based materials for drug delivery represents an area of active research, and the use of graphene in drug delivery systems is promising due to its unique properties. Thus, in the present work, we discuss the potential of few-layer graphene in a hydrogel system for dopamine release. The hydrogels are frequently used for these systems for their special physico-chemical properties, which can ensure that the drug is effectively released in time. However, the release from such structures is mostly determined by diffusion alone, and to overcome this restriction, the hydrogel can be "improved" with nanoscale fillers like graphene. The release kinetics of the composite obtained were analyzed to better understand how the use of graphene, instead of the more common graphene oxide (GO) and reduced graphene oxide (rGO), affects the characteristics of the system. Thus, the systems developed in this study consist of three main components: biopolymer, graphene, and dopamine. The hydrogels with graphene were prepared by combining two different solutions, one with polyacrylic acid and agarose and one with graphene prepared by the exfoliation method with microwave irradiation. The drug delivery systems were developed by adding dopamine to the obtained hydrogels. After 24 h of release, the presence of dopamine was observed, demonstrating that the system developed can slow down the drug's degradation because of the interactions with the graphene nanoplates and the polymer matrix.

Graphene-based nanomaterials for stimuli-sensitive controlled delivery of therapeutic molecules

Stimuli-responsive drug delivery has attracted tremendous attention in the past decades. It provides a spatial- and temporal-controlled release in response to different triggers, thus enabling highly efficient drug delivery and minimizing drug side effects. Graphene-based nanomaterials have been broadly explored, and they show great potential in smart drug delivery due to their stimuli-responsive behavior and high loading capacity for an extended range of drug molecules. These characteristics are a result of high surface area, mechanical stability and chemical stability, and excellent optical, electrical, and thermal properties. Their great and infinite functionalization potential also allows them to be integrated into several types of polymers, macromolecules, or other nanoparticles, leading to the fabrication of novel nanocarriers with enhanced biocompatibility and trigger-sensitive properties. Thus, numerous studies have been dedicated to graphene modification and functionalization. In the current review, we introduce graphene derivatives and different graphene-based nanomaterials utilized in drug delivery and discuss the most important advances in their functionalization and modification. Also, their potential and progress in an intelligent drug release in response to different types of stimuli either endogenous (pH, redox conditions, and reactive oxygen species (ROS)) or exogenous (temperature, near-infrared (NIR) radiation, and electric field) will be debated.

Enzyme immobilization in hydrogels: A perfect liaison for efficient and sustainable biocatalysis

Biocatalysis is an established chemical synthesis technology that has by no means been restricted to research laboratories. The use of enzymes for organic synthesis has evolved greatly from early development to proof-of-concept - from small batch production to industrial scale. Different enzyme immobilization strategies contributed to this success story. Recently, the use of hydrogel materials for the immobilization of enzymes has been attracting great interest. Within this review, we pay special attention to recent developments in this key emerging field of research. Firstly, we will briefly introduce the concepts of both biocatalysis and hydrogel worlds. Then, we list recent interesting publications that link both concepts. Finally, we provide an outlook and comment on future perspectives of further exploration of enzyme immobilization strategies in hydrogels.

MacGyvered Multiproperty Materials Using Nanocarbon and Jam: A Spectroscopic, Electromagnetic, and Rheological Investigation

As part of a biopolymer matrix, pectin was investigated to obtain an engineered jam, due to its biodegradability. Only a few examples of pectin-based nanocomposites are present in the literature, and even fewer such bionanocomposites utilize nanocarbon as a filler-mostly for use in food packaging. In the present paper, ecofriendly nanocomposites made from household reagents and displaying multiple properties are presented. In particular, the electrical behavior and viscoelastic properties of a commercial jam were modulated by loading the jam with carbon nanotubes and graphene nanoplates. A new nanocomposite class based on commercial jam was studied, estimating the percolation threshold for each filler. The electrical characterization and the rheological measurements suggest that the behavior above the percolation threshold is influenced by the different morphology-i.e., one-dimensional or two-dimensional-of the fillers. These outcomes encourage further studies on the use of household materials in producing advanced and innovative materials, in order to reduce the environmental impact of new technologies, without giving up advanced devices endowed with different physical properties.

Applications of Pristine and Functionalized Carbon Nanotubes, Graphene, and Graphene Nanoribbons in Biomedicine

This review is dedicated to a comprehensive description of the latest achievements in the chemical functionalization routes and applications of carbon nanomaterials (CNMs), such as carbon nanotubes, graphene, and graphene nanoribbons. The review starts from the description of noncovalent and covalent exohedral modification approaches, as well as an endohedral functionalization method. After that, the methods to improve the functionalities of CNMs are highlighted. These methods include the functionalization for improving the hydrophilicity, biocompatibility, blood circulation time and tumor accumulation, and the cellular uptake and selectivity. The main part of this review includes the description of the applications of functionalized CNMs in bioimaging, drug delivery, and biosensors. Then, the toxicity studies of CNMs are highlighted. Finally, the further directions of the development of the field are presented.

A Review on Recent Advancements of Graphene and Graphene-Related Materials in Biological Applications

Graphene is the most outstanding material among the new nanostructured carbonaceous species discovered and produced. Graphene’s astonishing properties (i.e., electronic conductivity, mechanical robustness, large surface area) have led to a deep change in the material science field. In this review, after a brief overview of the main characteristics of graphene and related materials, we present an extensive overview of the most recent achievements in biological uses of graphene and related materials.