Hydrogel Beads of Natural Polymers as a Potential Vehicle for Colon-Targeted Drug Delivery

Polysaccharides are excellent candidates for drug delivery applications as they are available in abundance from natural sources. Polysaccharides such as starch, cellulose, lignin, chitosan, alginate, and tragacanth gum are used to make hydrogels beads. Hydrogels beads are three-dimensional, cross-linked networks of hydrophilic polymers formed in spherical shape and sized in the range of 0.5-1.0 mm of diameter. Beads are formed by various cross-linking methods such as chemical and irradiation methods. Natural polymer-based hydrogels are biocompatible and biodegradable and have inherently low immunogenicity, which makes them suitable for physiological drug delivery approaches. The cross-linked polysaccharide-based hydrogels are environment-sensitive polymers that can potentially be used for the development of "smart" delivery systems, which are capable of control release of the encapsulated drug at a targeted colon site. This topic focuses on various aspects of fabricating and optimizing the cross-linking of polysaccharides, either by a single polysaccharide or mixtures and also natural-synthetic hybrids to produce polymer-based hydrogel vehicles for colon-targeted drug delivery.

Recent advancements in the applications of carbon nanodots: exploring the rising star of nanotechnology

Nanoparticles possess fascinating properties and applications, and there has been increasing critical consideration of their use. Because carbon is a component with immaterial cytotoxicity and extensive biocompatibility with different components, carbon nanomaterials have a wide scope of potential uses. Carbon nanodots are a type of carbon nanoparticle that is increasingly being researched because of their astounding properties such as extraordinary luminescence, simplicity of amalgamation and surface functionalization, and biocompatibility. Because of these properties, carbon nanodots can be used as material sensors, as indicators in fluorescent tests, and as nanomaterials for biomedical applications. In this review, we report on the ongoing and noteworthy utilization of carbon quantum dots such as bioimaging tests and photocatalytic applications. In addition, the extension and future components of these materials, which can be investigated for new potential applications, are discussed.

Electrospun cellulose acetate butyrate/polyethylene glycol (CAB/PEG) composite nanofibers: A potential scaffold for tissue engineering

Electrospinning is a common method to prepare nanofiber scaffolds for tissue engineering. One of the common cellulose esters, cellulose acetate butyrate (CAB), has been electrospun into nanofibers and studied. However, the intrinsic hydrophobicity of CAB limits its application in tissue engineering as it retards cell adhesion. In this study, the properties of CAB nanofibers were improved by fabricating the composite nanofibers made of CAB and hydrophilic polyethylene glycol (PEG). Different ratios of CAB to PEG were tested and only the ratio of 2:1 resulted in smooth and bead-free nanofibers. The tensile test results show that CAB/PEG composite nanofibers have 2-fold higher tensile strength than pure CAB nanofibers. The hydrophobicity of the composite nanofibers was also reduced based on the water contact angle analysis. As the hydrophilicity increases, the swelling ability of the composite nanofiber increases by 2-fold with more rapid biodegradation. The biocompatibility of the nanofibers was tested with normal human dermal fibroblasts (NHDF). The cell viability assay results revealed that the nanofibers are non-toxic. In addition to that, CAB/PEG nanofibers have better cell attachment compared to pure CAB nanofibers. Based on this study, CAB/PEG composite nanofibers could potentially be used as a nanofiber scaffold for applications in tissue engineering.

Optimisation of preparation conditions for Ti nanowires and suitability as an antibacterial material

Ultrafine titanium dioxide (TiO₂) nanowires were synthesised using a hydrothermal method with different volumes of ethylene glycol (EG) and annealing temperatures. It shows that sodium titanate nanowires synthesised using 5 and 10 ml EG, which annealed at 400°C produced TiO₂ nanowires that correspond to a photochemically active phase, which is anatase. The influences of annealing temperatures (400-600°C) on the morphological arrangement of TiO₂ nanowires were evident in the field emission scanning electron microscopy. The annealing temperature of 500°C led to agglomeration, which formed a mixture of TiO₂ nanoparticles and nanowires. High thermal stability of TiO₂ nanowires revealed by thermogravimetric analysis and Fourier transform infrared spectroscopy spectrum showed the presence of the Ti-O-Ti vibrations as evidenced due to TiO₂ lattices. An antibacterial study using TiO₂ nanowires toward Escherichia coli and Klebsiella pneumoniae showed large zones of inhibition that indicated susceptibility of the microbe toward TiO₂. Growth kinetic analysis shows that addition of TiO₂ has reduced optical density (OD) suggesting an inhibition of the growth of bacteria. These results indicate TiO₂ nanowires can be effectively used as an antimicrobial agent against gram-bacteria. The TiO₂ nanowires could be exploited in the medical, packaging and detergent formulation industries and wastewater treatment.

Application of Metal Nanoparticle⁻Hydrogel Composites in Tissue Regeneration

Challenges in organ transplantation such as high organ demand and biocompatibility issues have led scientists in the field of tissue engineering and regenerative medicine to work on the use of scaffolds as an alternative to transplantation. Among different types of scaffolds, polymeric hydrogel scaffolds have received considerable attention because of their biocompatibility and structural similarity to native tissues. However, hydrogel scaffolds have several limitations, such as weak mechanical property and a lack of bioactive property. On the other hand, noble metal particles, particularly gold (Au) and silver (Ag) nanoparticles (NPs), can be incorporated into the hydrogel matrix to form NP⁻hydrogel composite scaffolds with enhanced physical and biological properties. This review aims to highlight the potential of these hybrid materials in tissue engineering applications. Additionally, the main approaches that have been used for the synthesis of NP⁻hydrogel composites and the possible limitations and challenges associated with the application of these materials are discussed.