Gel Transformation Research Articles

Ionic liquid–based aqueous biphasic system as an alternative tool for enhanced bacterial DNA extraction

BackgroundDeveloping an alternative and benign method for DNA extraction is imperative due to the high cost and potential harms associated with conventional techniques. Investigation of Ionic liquid (IL) as a solvent for DNA storage and stability revealed the ability of IL to assist DNA processes. IL–based aqueous biphasic system emerges as a comprehensive extraction platform capitalizing on the task–specificity of ILs and the wide applicability of ABS for biomolecule extractions. Therefore, it is beneficial to optimize an IL–based ABS specifically for DNA extraction, taking into account the fundamental interactions between the IL and DNA. ResultsThe primary objective was to design ABS consisting of Ammonium based ILs, and Potassium phosphate buffer as the salting–out agent for the partitioning of salmon sperm DNA. The analysis focused on optimizing biocompatible anions for the extraction. Moreover, the stability of the DNA in the IL rich phases was analysed to validate the method. The proposed process was then employed for extracting plasmid DNA from bacteria, demonstrating results comparable to those obtained with a commercially available kit. Further validation using agarose gel electrophoresis and transformation of the extracted DNA into E.coli were conducted, producing promising outcomes. Although there is room for improvement in terms of recovery of DNA and reusability of ABS, the described approach is comparable with the conventional one while being cost–effective, and showcases a noticeable and convincing link to eco–friendly processes. SignificanceThere is limited literature on IL–based ABS for DNA extraction, and the existing studies predominantly concentrate on systems derived from Cholinium ILs. However, their high hydrophilicity limits the choice of the second–phase forming component to polymers for the formation of ABS. Ammonium ILs efficiently form biphasic systems with various available salting–out agents, and biocompatible anions are introduced to mitigate the toxicity of the ILs.

Structure, characterization, and application of a novel thermoreversible emulsion gel fabricated by citrate agar

A novel thermoreversible emulsion gel was successfully prepared with citrate agar (CA) as the sole emulsifier. Compared with native agar gel emulsion, CA gel emulsion (CAGE) formed a stable emulsion gel when the CA concentration was increased to 1.25 % (w/w). Results of time-temperature scanning experiments showed that the emulsion gel rapidly transformed into liquid emulsion when heated to 40–50 °C and then solidified into emulsion gel after cooling to the critical temperature of solidification. The emulsion gel had stable sol–gel transformation ability after seven cycles repeated heating–cooling treatment (HCT) at 85 °C and 4 °C. However, the stability of emulsion gels gradually decreased because of the large-droplet formation during heating, which affected the CA molecular-reconfiguration network structure in cooling. The conjunction analysis of microstructure and properties of the emulsion gel indicated that its stability depended primarily on the spatial repulsion and electrostatic repulsion provided by CA gel, and the main factor driving thermal reversibility was the temperature-responsive gelation performance of CA. The retention of quercetin was >90.23 % after seven HCTs because CAGEG enhanced the homogeneity and stability of the droplets.

Effects of hydrotalcites with different laminate element composition on the properties of sulfoaluminate cement-based materials

Sulfoaluminate cement-based materials (SCBMs) are widely used for grout reinforcement. It is common to use a large water-to-binder ratio in the construction of sulfoaluminate cement-based materials (SAGMs) to obtain good workability and permeability, which results in poor early strength. Nanotechnology has been increasingly employed to enhance the mechanical properties of cementitious materials. Nano Zn-Mg-Al hydrotalcite-like (LDHs) and nano Mg-Al LDHs increased the early compressive strength, while nano Zn-Al LDHs had the opposite effect. However, the reason for this observation remains unclear. In this study, the influence of LDHs structures with different laminar element compositions on the hydration and hardening processes of SCBMs was analysed. The results showed that nano-ZnAl-LDHs, ZnAl-LDHs, and MgAl-LDHs could provide nucleation sites for ettringites. The three hydrotalcite-like materials slowly released different concentrations of zinc and/or magnesium ions and carbonate ions in the cement paste. Zinc ions entered the hydration product of ettringite and aluminum gel and promoted the transformation of amorphous aluminum gel to bayerite, which inhibited the hydration reaction of SCBMs. Magnesium ions could also enter the ettringite, and carbonate ions promoted the formation of calcium carbonate, which facilitated the hydration reaction of SCBMs. The nucleation effect and the release of zinc and/or magnesium ions and carbonate ions acted synergically to influence the hydration rate, pore size distribution, and compressive strength of SCBMs.

Tumor Microenvironment‐Selective Sol–Gel Mineralization of ROS‐Responsive Stretchable and Conductive Hydrogel

AbstractCancer cell‐triggered sol–gel transformation of mineralized hydrogel (PAA‐MnO2) is designed as a facile strategy for cancer detection by manipulating the mineralization process in the presence of cancer cells. The mineralization of polyacrylic acid (PAA) with calcium phosphate via carboxyl‐Ca2+ complex is initially inhibited by the incorporation of reactive oxygen species (ROS)‐sensitive manganese oxide (MnO2) with polymer dots (PDs). In this system, the mineralization can be induced after cleaving MnO2 into Mn2+ by high ROS levels in cancer cells, forming a PAA‐MnO2 mineralized hydrogel and resulting in a naked‐eye system for cancer monitoring. Naked‐eye monitoring of ROS‐responsive sol–gel transformation is performed using a circulator device containing circulating cells to discriminate cancer (HeLa, PC‐3, B16F10) from normal cells (CHO‐K1). With the incorporation of PDs, PAA‐MnO2 mineralized hydrogel not only provides physical transformation (stretchability, viscosity) but also fluorescence‐recovery and electroconductivity changes at different cancer‐cell concentrations (104–106 cells mL−1), including distinct strain–pressure responses that can be wirelessly monitored via smartphones. Furthermore, in vivo, experiments suggest that PAA‐MnO2 mineralized hydrogel can be formed in tumor‐bearing mice owing to its excellent ROS‐scavenging activity at the tumor site, as confirmed by SOD2 and gene‐expression analysis. Thus, this unique approach can potentially enable simple and effective cancer detection in future point‐of‐care diagnostics.

Experimental study on performance, hydration, and sustainability of coal gasification coarse slag based geopolymers for sustainable environment

The large-scale application of coal gasification technology generates a large amount of coal gasification coarse slag (CGCS) difficult to treat. In this study, low-carbon geopolymers (CGRC) were produced using CGCS and ground granulated blast furnace slag (GGBS) as precursors, whereas red mud (RM) and carbide slag (CS) served as solid waste activators. The effects of the binder/activator, RM/CS and CGCS/GGBS ratios and the curing age on the compressive strength, setting time, heavy metal leaching, XRD, SEM-EDS, TG-DTG, FTIR, and LF NMR of CGCS-based geopolymers were investigated, and the hydration mechanism of CGRC geopolymer was disclosed. The results showed that the binder/activator ratio had a negligible effect on the ultimate compressive strength (UCS), the RM/CS ratio had a noticeable impact on the compressive strength and setting time, and increasing the GGBS content significantly improved the performance of CGCS-based geopolymers. Therefore, the synergistic effect of RM and CS led to the activation of CGCS and GGBS. The main hydration products were N-A-S-H, N/C-A-S-H, C-A-S-H gel, CH, and CaCO3. Furthermore, the decrease of the RM/CS ratio which promoted the gel transformation from metastable N-A-S-H to N/C-A-S-H configuration and then to stable C-A-S-H state, finally forming a denser gel matrix. The amounts of various heavy metals leached from CGCS-based geopolymers were even lower than those required by the national standards; therefore the material met the requirements for environmental protection. Furthermore, all raw materials belong to solid waste, which reduces carbon emissions.

Hydrogel design to overcome thermal resistance and ROS detoxification in photothermal and photodynamic therapy of cancer

Responsive heat resistance (by heat shock protein upregulation) and spontaneous reactive oxygen species (ROS) detoxification have been regarded as the major obstacles for photothermal/photodynamic therapy of cancer. To overcome the thermal resistance and improve ROS susceptibility in breast cancer therapy, Au ion-crosslinked hydrogels including indocyanine green (ICG) and polyphenol are devised. Au ion has been introduced for gel crosslinking (by catechol-Au3+ coordination), cellular glutathione depletion, and O2 production from cellular H2O2. ICG can generate singlet oxygen from O2 (for photodynamic therapy) and induce hyperthermia (for photothermal therapy) under the near-infrared laser exposure. (−)-Epigallocatechin gallate downregulates heat shock protein to overcome heat resistance during hyperthermia and exerts multiple anticancer functions in spite of its ironical antioxidant features. Those molecules are concinnously engaged in the hydrogel structure to offer fast gel transformation, syringe injection, self-restoration, and rheological tuning for augmented photo/chemotherapy of cancer. Intratumoral injection of multifunctional hydrogel efficiently suppressed the growth of primary breast cancer and completely eliminated the residual tumor mass. Proposed hydrogel system can be applied to tumor size reduction prior to surgery of breast cancer and the complete remission after its surgery.

Amoeboid soft robot based on multi-material composite 3D printing technology

A core–shell structured, amoeba-like, magnetically controlled soft robot is proposed for 3D printing using magnetically controlled smart materials and silicone materials. The purpose of this robot is to overcome the limitations of existing soft robot kinematic mechanisms that rely on the elastic deformation of flexible materials. The printability of the magnetically controlled smart material was verified through rheological tests. The effect of different component ratios on the rheological properties of the material was investigated and a suitable material ratio for printing was selected by adjusting the amount of SiO2 in the silicone and conducting rheological tests. Mechanical simulation was used to select and optimize the design of the amoeboid soft robotic shell structures. Printing was then used to verify the stability of the shell structures. The self-supporting capability of the magnetically controlled smart materials was investigated under different magnetic field strengths. To solve the problem of the phase of the magnetron smart material and the silicone material, the composite printing of the two materials was accomplished by adjusting the printing process. Soft robots mimicking amoebas were then printed and fabricated. The magnetron array-based driving method is proposed, and the magnetic field of the array used to drive the amoeba-like soft robot is constructed. The magnetic field of the array surface was then simulated under several different driving modes. Based on the simulation results, a suitable driving mode was selected. Using the material mechanism of the magnetron-only material sol–gel transformation, the pseudopod extension gait of the amoeba-like soft robot was designed, and the localized deformation of the amoeba-like soft robot was realized.This paper leveraged the distinctive properties of magnetorheological smart materials to devise and fabricate an integrated 3D-printed soft robot. Such magnetorheological smart materials can function as both the supporting framework for hollow cavities and the propelling substance for the robot. During the course of this process, we investigated material properties pertinent to 3D printing and refined the design of the robot's structure and driving mechanism.

Sodium alginate-based smart gastro-retentive drug delivery system of revaprazan loaded SLNs; Formulation and characterization

Revaprazan (REV), a novel reversible Proton Pump Inhibitor (PPI) used to treat peptic ulcers, faces challenges in therapeutic efficacy due to its poor dissolution properties and a short half-life. Solid lipid nanoparticles (SLNs) have emerged as a drug delivery system capable of enhancing dissolution and bioavailability of lipid soluble drugs. Here, we report on the development and optimization of a smart gastro-retentive raft system of REV-loaded SLNs (GRS/REV-SLNs) to enhance drug bioavailability and gastric retention. The optimized REV-SLNs had a particle size of 120 nm, a Polydispersity Index (PDI) of 0.313, a zeta potential of −20.7 mV, and efficient drug incorporation of 88 %. Transmission Electron Microscopy (TEM) affirmed the spherical morphology of these REV-SLNs, while Fourier Transform Infrared Spectroscopy (FTIR) revealed no chemical interactions among components. In-vitro assessment of the final GRS/REV-SLNs demonstrated sustained gelation and buoyancy for over 12 h, which would significantly enhance REV retention and its release within the stomach. Further assessments in rats confirmed successful gel transformation within the stomach, resulting in the improved bioavailability of REV. Thus, the development of GRS/REV-SLNs significantly improved the delivery and bioavailability of REV within the stomach, and offers a potentially improved method of treating peptic ulcers.

Translucent and Anti-ultraviolet Aramid Nanofiber Films with Efficient Light Management Fabricated by Sol–Gel Transformation

Translucent and Anti-ultraviolet Aramid Nanofiber Films with Efficient Light Management Fabricated by Sol–Gel Transformation

Computational Insight of Phase Transformation and Drug Release Behaviour of Doxycycline-Loaded Ibuprofen-Based In-Situ Forming Gel.

This research investigates the gel formation behaviour and drug-controlling performance of doxycycline-loaded ibuprofen-based in-situ forming gels (DH-loaded IBU-based ISGs) for potential applications in periodontal treatment. The investigation begins by exploring the physical properties and gel formation behaviour of the ISGs, with a particular focus on determining their sustained release capabilities. To gain a deeper understanding of the molecular interactions and dynamics within the ISGs, molecular dynamic (MD) simulations are employed. The effects of adding IBU and DH on reducing surface tension and water tolerance properties, thus affecting molecular properties. The phase transformation phenomenon is observed around the interface, where droplets of ISGs move out to the water phase, leading to the precipitation of IBU around the interface. The optimization of drug release profiles ensures sustained local drug release over seven days, with a burst release observed on the first day. Interestingly, different organic solvents show varying abilities to control DH release, with dimethyl sulfoxide (DMSO) demonstrating superior control compared to N-Methyl-2-pyrrolidone (NMP). MD simulations using AMBER20 software provide valuable insights into the movement of individual molecules, as evidenced by root-mean-square deviation (RMSD) values. The addition of IBU to the system results in the retardation of IBU molecule movement, particularly evident in the DMSO series, with the diffusion constant value of DH reducing from 1.2452 to 0.3372 and in the NMP series from 0.3703 to 0.2245 after adding IBU. The RMSD values indicate a reduction in molecule fluctuation of DH, especially in the DMSO system, where it decreases from over 140 to 40 Å. Moreover, their radius of gyration is influenced by IBU, with the DMSO system showing lower values, suggesting an increase in molecular compactness. Notably, the DH-IBU configuration exhibits stable pairing through H-bonding, with a higher amount of H-bonding observed in the DMSO system, which is correlated with the drug retardation efficacy. These significant findings pave the way for the development of phase transformation mechanistic studies and offer new avenues for future design and optimization formulation in the ISG drug delivery systems field.

Investigation of the relationship among the hydration, microstructure and compressive strength of alkali-activated phosphorus slag

In this study, the relationship among the hydration, microstructure and compressive strength of alkali-activated phosphorus slag (AAPS) was systematically investigated to provide a foundation for its design and application. The alkali dose and silicate modulus had both positive and negative effects on PS hydration due to the change in the pH, the concentrations of Si-containing ions and the hydrate coating on the PS surface, and the overall effect depended on their relative magnitudes. The hydration of waterglass-activated phosphorus slag (WAPS) experienced a transformation of NASH first into CNASH (low Ca) and then into CNASH (high Ca) due to the stronger polarization ability of Ca2+ over Na+, and the gel transformation was accompanied by dealumination. The more early hydrates there were, the higher the early densification and early compressive strength of AAPS. The later densification and later compressive strength were influenced by a combination of the hydrate content, early hydration rate and gel type. CNASH (high Na) was incompatible with CNASH (low Na), which degraded the later densification. When the contents of later hydrates were comparable, the slower early hydration and lower CNASH (high Na) contributed to the greater later densification and compressive strength.

Nasal mucoadhesive in situ gelling liquid crystalline fluid precursor system of polyene antibiotic for potential treatment of localized sinuses aspergillosis post COVID infection

Nasal mucoadhesive in situ gelling liquid crystalline precursor system (IGFPS) of nystatin was developed for localized treatment of nasal aspergillosis post COVID infection. The stimuli-sensitive sol system comprising of Monoolein (60%w/w), Oleic acid (10%w/w), Dimethyl sulfoxide (15%w/w), Poloxamer 407 (9%w/w), and the drug (2.23%w/w) exhibited a faster sol–gel transformation in situ with good swelling ability. The small angle X-ray scattering study identified the coexistence of Im3m cubic phase with hexagonal closed pack P63/mmc structures. The subzero differential scanning calorimetry studies identified entrapped interphasal water and free water in the gels with confirmation of gelation due to micellization. Mucoadhesive properties of the gel indicate these systems to prolong the residence time at the site of absorption. The gels followed Non-Newtonian flow pattern characteristic of pesudoplastic type. The oscillatory rheology revealed that high complex viscosity and lower tanδ value provided superior adhesiveness and mucoadhesion ability to the gel. The gel exhibited a drug release of 86% at the end of 8h and of Higuchi kinetics with anomalous transport. The IGFPS exhibited better in vitro antifungal activity in comparison to drug solution. The system demonstrated permeation enhancing effect undamaged cilia and no serious histological changes. Post intranasal administration the maximum concentration (11.79 ± 2.31 μg/ml) was realized in 20 min and the curve showed a decline similar to intravenous. The storage stability of the IGFPS was found to be within acceptable limits for stability. Thus, a nasal mucoadhesive in situ gelling fluid liquid crystalline precursor formulation may represent a promising novel alternative for the localized and systemic delivery of nystatin.

Environmental risks of antibiotic resistance genes released from biological laboratories and its control measure.

Antibiotic resistance genes (ARGs) are a growing global threat to public health. Biological laboratory wastewater contains large amounts of free ARGs. It is important to assess the risk of free ARGs from biological laboratories and to find appropriate treatments to control their spread. The fate of plasmids in the environment and the effect of different thermal treatments on their persistence activity were tested. The results showed that untreated resistance plasmids could exist in water for more than 24h (the special 245bp fragment). Gel electrophoresis and transformation assays showed that the plasmids boiled for 20min retained 3.65% ± 0.31% transformation activity of the intact plasmids, while autoclaving for 20min at 121°C could effectively degrade the plasmids and that NaCl, bovine serum albumin, and EDTA-2Na affected the degradation efficiency of the plasmids during boiling. In the simulated aquatic system, using 106 copy/μL of plasmids after autoclaving, only 102 copies/μL of the fragment after only 1-2h could be detected. By contrast, boiled plasmids for 20min were still detectable after plunging them into water for 24h. These findings suggest that untreated and boiled plasmids can remain in the aquatic environment for a certain time resulting in the risk of disseminating ARGs. However, autoclaving is an effective way of degrading waste free resistance plasmids.

In Situ Structure Transformation of a Sprayed Gel for pH-Ultrasensitive Nano-Catalytic Antibacterial Therapy.

Nano-catalytic bacterial killing provides new opportunities to address ever-increasing antibiotic resistance. However, the intrinsic catalytic activity usually depends on a much lower pH conditions (pH=2-5) than that in the weakly acidic bacterial microenvironments (pH=6-7) for reactive oxygen species production by Fenton reactions. Herein, a MnSiO3 -based pH-ultrasensitive "in situ structure transformation" is first reported to significantly promote the adhesion between material and bacteria, and shorten the diffusion distance (<20nm) to compensate ultra-short life (<200ns) of ·OH generated by Mn2+ -mediated Fenton-like reaction, finally enhancing its nano-catalytic antibacterial performance in weakly acidic conditions. A separated spray bottle is further designed to achieve in situ gelation at the wound site, which demonstrates excellent shape adaptability to complicated and rough surfaces of wounds, allowing for long-term nano-catalyst release. As a result, bacterial-infected wound healing is efficiently promoted. Herein, the in situ sprayed nano-catalytic antibacterial gel presents a promising paradigm for bacterial infection treatment.

Encapsulation of liquid metal nanoparticles inside metal–organic frameworks for hydrogel-integrated dual functional biotherapy

Liquid metals represent emerging functional materials for many applications, yet their chemistries for surface/interface engineering and composite development have remained elusive. Here, we present a nanocomposite material featured by a liquid metal core encapsulated in a zeolitic-imidazolate framework shell. An initial functionalization step of liquid metal nanoparticles with amphiphilic surfactant molecules allows on-demand manipulation of the interparticle assembly between liquid metals and metal–organic frameworks, yielding a supraparticle-like composite material with multilevel surface structure and synergistic multifunctionality. The resulting supraparticles are employed as light-activable nanofillers in an alginate-based hydrogel, which displays good injectability, physiologically responsive sol–gel transformation, stable photothermal performance, and controllable zinc ion release. A temperature increase of 31.0 °C is achieved with the composite hydrogel after laser irradiation for 10 min (808 nm laser, 1.5 W/cm2). The composite hydrogel then serves as safe, biodegradable (65.2 % degradation 14 days post implantation), dual functional antitumor and antibacterial biomedicine in an epidermal tumor model and an abscess model. Tumor cells/bacteria seeded on mice are completely (∼100 %) eradicated after a single treatment with laser-activated composite hydrogel. This study offers a pioneering road map for the design and fabrication of liquid metal/metal–organic framework composites, which is expected to trigger broad innovations in liquid metal nanotechnologies not limited to nano/biomedicine.

Gel transformation as a general strategy for fabrication of highly porous multiscale MOF architectures.

The structure and chemistry of metal-organic frameworks or MOFs dictate their properties and functionalities. However, their architecture and form are essential for facilitating the transport of molecules, the flow of electrons, the conduction of heat, the transmission of light, and the propagation of force, which are vital in many applications. This work explores the transformation of inorganic gels into MOFs as a general strategy to construct complex porous MOF architectures at nano, micro, and millimeter length scales. MOFs can be induced to form along three different pathways governed by gel dissolution, MOF nucleation, and crystallization kinetics. Slow gel dissolution, rapid nucleation, and moderate crystal growth result in a pseudomorphic transformation (pathway 1) that preserves the original network structure and pores, while a comparably faster crystallization displays significant localized structural changes but still preserves network interconnectivity (pathway 2). MOF exfoliates from the gel surface during rapid dissolution, thus inducing nucleation in the pore liquid leading to a dense assembly of percolated MOF particles (pathway 3). Thus, the prepared MOF 3D objects and architectures can be fabricated with superb mechanical strength (>98.7 MPa), excellent permeability (>3.4 × 10-10 m2), and large surface area (1100 m2 g-1) and mesopore volumes (1.1 cm3 g-1).

A facile strategy of preparing nanosized NaY zeolite by stimulating negative crystals to accelerate the formation of D6R units

Nanosized Y zeolite has excellent potential as a catalyst or adsorbent to boost the chemical industry. However, the synthesis of nanosized Y zeolite under traditional industrial conditions still faces many huge challenges. Herein, we report a facile strategy of preparing nanosized NaY zeolite by applying sodium halides (NaCl or NaBr) to regulate amorphous gel. Sodium halides regulate the micro-structural transformation of the initial amorphous gel during the induction period and promote the polymerization between silicate ions and aluminosilicate. Thus, many more negative crystals are stimulated to form and the emergence of double six-ring (D6R) building units is accelerated. In a short 12 h, nanosized NaY zeolite with small crystal size (about 100 nm), large pore volume (0.476 cm3 g−1), and rich mesoporous volume (0.165 cm3 g−1) is synthesized. These synthesized nanosized NaY zeolites are expected to be better precursors to exert their advantages.

Chemical Transformations of Vanadium-Containing Silica Gel in Contact with Water Vapor According to AFM and ESDR Data

Chemical Transformations of Vanadium-Containing Silica Gel in Contact with Water Vapor According to AFM and ESDR Data

Preparation of Thermosensitive Hydroxybutyl Chitosan/Silk Fibroin Hybrid Hydrogels

AbstractEndowing silk fibroin (SF) with the thermosensitivity of rapid in situ gelation remains a challenge in the field of silk fibroin‐based tissue engineering scaffolds and injectable soft tissue fillers. In this study, thermosensitive hydroxybutyl chitosan (HBC)/SF hybrid hydrogels are prepared by physical interaction between HBC and SF. In HBC/SF hybrid system, hydrophobic segments of HBC are aggregated to form microaggregates at physiological temperature, which induce hydrophobic segments of SF to aggregate to the microaggregates by hydrophobic interaction, thus achieving the sol–gel transformation of the two components jointly. The observations and tests of the gelation process show that HBC/SF hybrids with mass ratios of 95/5, 90/10, 85/15, 80/20, 75/25, and 70/30 can complete sol–gel transition rapidly within 5–8 min at 37 °C, and have the reversibility of sol–gel transition. CCK‐8 assay results reveal that the cytotoxicity of HBC hydrogel is effectively reduced by the introduction of SF component. Thermosensitive HBC/SF hybrids have the potential to be used as injectable tissue engineering scaffolds and soft tissue filler.

Alginate-Based Bio-Composites and Their Potential Applications.

Over the last two decades, bio-polymer fibers have attracted attention for their uses in gene therapy, tissue engineering, wound-healing, and controlled drug delivery. The most commonly used bio-polymers are bio-sourced synthetic polymers such as poly (glycolic acid), poly (lactic acid), poly (e-caprolactone), copolymers of polyglycolide and poly (3-hydroxybutyrate), and natural polymers such as chitosan, soy protein, and alginate. Among all of the bio-polymer fibers, alginate is endowed with its ease of sol–gel transformation, remarkable ion exchange properties, and acid stability. Blending alginate fibers with a wide range of other materials has certainly opened many new opportunities for applications. This paper presents an overview on the modification of alginate fibers with nano-particles, adhesive peptides, and natural or synthetic polymers, in order to enhance their properties. The application of alginate fibers in several areas such as cosmetics, sensors, drug delivery, tissue engineering, and water treatment are investigated. The first section is a brief theoretical background regarding the definition, the source, and the structure of alginate. The second part deals with the physico-chemical, structural, and biological properties of alginate bio-polymers. The third part presents the spinning techniques and the effects of the process and solution parameters on the thermo-mechanical and physico-chemical properties of alginate fibers. Then, the fourth part presents the additives used as fillers in order to improve the properties of alginate fibers. Finally, the last section covers the practical applications of alginate composite fibers.