Self-assembled polymer nanocomposites for biomedical application

Biomedical applications of natural and synthetic polymer based nanocomposites

Various nanomaterials have been studied for their biomedical application in recent years. Among them, nanocomposites have a prominent medical application in the prevention, diagnosis, and treatment of various diseases. Nanocomposites are made up of polymeric matrix layers composed of synthetic or natural polymers like chitosan, polyethylene glycol, etc. Polymer nanocomposites are inorganic nanoparticles dispersed in a polymer matrix. There are two types of polymeric nanocomposites which include natural and synthetic polymer nanocomposites. These nanocomposites have various biomedical applications, such as medical implants, wound healing, wound dressing, bone repair and replacement, and dental filling. Polymeric nanocomposites have a wide range of biomedical applications due to their high stability, non-immunogenic nature, sustained drug delivery, non-toxic, and can escape reticuloendothelial system uptake along with drug bioavailability improvement. In this review, we have discussed various types of natural and synthetic polymer nanocomposites and their biomedical applications.

Catalytic polymer nanocomposites for environmental remediation of wastewater

The removal of harmful chemicals and species from water, soil, and air is a major challenge in environmental remediation, and a wide range of materials have been studied in this regard. To identify the optimal material for particular applications, research is still ongoing. Polymer nanocomposites (PNCs), which combine the benefits of nanoparticles with polymers, an alternative to conventional materials, may open up new possibilities to overcome this difficulty. They have remarkable mechanical capabilities and compatibility due to their polymer matrix with a very high surface area to volume ratio brought about by their special physical and chemical properties, and the extremely reactive surfaces of the nanofillers. Composites also provide a viable answer to the separation and reuse problems that hinder nanoparticles in routine use. Understanding these PNCs materials in depth and using them in practical environmental applications is still in the early stages of development. The review article demonstrates a crisp introduction to the PNCs with their advantageous properties as a catalyst in environmental remediation. It also provides a comprehensive explanation of the design procedure and synthesis methods for fabricating PNCs and examines in depth the design methods, principles, and design techniques that guide proper design. Current developments in the use of polymer nanocomposites for the pollutant treatment using three commonly used catalytic processes (catalytic and redox degradation, electrocatalytic degradation, and biocatalytic degradation) are demonstrated in detail. Additionally, significant advances in research on the aforementioned catalytic process and the mechanism by which contaminants are degraded are also amply illustrated. Finally, there is a summary of the research challenges and future prospects of catalytic PNCs in environmental remediation.

Metal/metal oxide-carbohydrate polymers framework for industrial and biological applications: Current advancements and future directions

Recently, the development and consumption of metal/metal oxide carbohydrate polymer nanocomposites (M/MOCPNs) are withdrawing significant attention because of their numerous salient features. Metal/metal oxide carbohydrate polymer nanocomposites are being used as environmentally friendly alternatives for traditional metal/metal oxide carbohydrate polymer nanocomposites exhibit variable properties that make them excellent prospects for a variety of biological and industrial uses. In metal/metal oxide carbohydrate polymer nanocomposites, carbohydrate polymers bind with metallic atoms and ions using coordination bonding in which heteroatoms of polar functional groups behave as adsorption centers. Metal/metal oxide carbohydrate polymer nanocomposites are widely used in woundhealing, additional biological uses and drug delivery, heavy ions removal or metal decontamination, and dye removal. The present review article features the collection of some major biological and industrial applications of metal/metal oxide carbohydrate polymer nanocomposites. The binding affinity of carbohydrate polymers with metal atoms and ions in metal/metal oxide carbohydrate polymer nanocomposites has also been described.

Biomedical applications of biodegradable polycaprolactone-functionalized magnetic iron oxides nanoparticles and their polymer nanocomposites

Magnetic nanoparticles (MNPs) have gained significant attention among several nanoscale materials during the last decade due to their unique properties. These properties make them successful nanofillers for drug delivery and a number of new biomedical applications. MNPs are more useful when combined with biodegradable polymers. In this review, we discussed the synthesis of polycaprolactones (PCL) and the various methods of synthesizing magnetic iron oxide nanoparticles. Then, the synthesis of composites that is made of PCL and magnetic materials (with special focus on iron oxide nanoparticles) were highlighted. In addition, we comprehensively reviewed their application in drug delivery, cancer treatment, wound healing, hyperthermia, and bone tissue engineering. Other biomedical applications of the magnetic PCL such as mitochondria targeting are highlighted. Moreover, biomedical applications of magnetic nanoparticles incorporated into other synthetic polymers apart from PCL are also discussed. Thus, great progress and better outcome with functionalized MNPs enhanced with polycaprolactone has been recorded with the biomedical applications of drug delivery and recovery of bone tissues.

Metal-Polymer Nanocomposites: A Promising Approach to Antibacterial Materials

There has been a new approach in the development of antibacterials in order to enhance the antibacterial potential. The nanoparticles are tagged on to the surface of other metals or metal oxides and polymers to achieve nanocomposites. These have shown significant antibacterial properties when compared to nanoparticles. In this article we explore the antibacterial potentials of metal-based and metal-polymer-based nanocomposites, various techniques which are involved in the synthesis of the metal-polymer, nanocomposites, mechanisms of action, and their advantages, disadvantages, and applications.

Self-assembled polylactic acid (PLA): Synthesis, properties and biomedical applications

The surface morphology and topography of cell culture substrates play an important role in cell proliferation and growth. Regulation of the surface microstructure allows the development of tissue culture media suitable for different cells. Polylactic acid (PLA) is a biobased and biodegradable (under defined conditions) polymer with low immunogenicity, non-toxicity, and good mechanical properties, which have facilitated their pharmaceutical and biomedical applications. This review summarizes recent advances in the synthesis and self-assembly of surface microstructure based on PLA materials and discusses their biomedical applications such as cell culturing and tissue engineering.

Bio-hybrid electronic and photonic devices

Bio-hybrid devices, combining electronic and photonic components with cells, tissues, and organs, hold potential for advancing our understanding of biology, physiology, and pathologies and for treating a wide range of conditions and diseases. In this review, I describe the devices, materials, and technologies that enable bio-hybrid devices and provide examples of their utilization at multiple biological scales ranging from the subcellular to whole organs. Finally, I describe the outcomes of a National Science Foundation (NSF)-funded workshop envisioning potential applications of these technologies to improve health outcomes and quality of life.

Obtaining Ultrafine Dispersions of Silver Particles in Poly(vinyl Alcohol) Matrix Using Mechanical Alloying

Mechanical alloying was performed to obtain a composite material with a homogeneous dispersion of silver particles in a poly(vinyl alcohol) (PVA) matrix. Silver is a bactericidal material, and PVA is a widely used biocompatible polymer. Therefore, this mix can lead to a potentially functional biomaterial. This study focuses on the combination of both materials, processed by mechanical alloying, which has a promising application potential. The silver (Ag) used was ultrafine, measuring between 200 and 400 nanometers, produced from silver nitrate (AgNO₃) redox. The Attritor high–energy, water–cooled ball mill was used to mill PVA for 4 h, at 600 rpm speed rotation and 38:1 power milling. Mechanical alloying was demonstrated to cause particle refinement in PVA with a timespan of 1 h. A slight additional particle decrease occurred for long–time milling. A milling time of 4 h was used to disperse the silver particles in the polymer matrix homogeneously. Hot pressing films were produced from the obtained dispersion powders. The microstructural features were studied using several material characterization techniques. Antimicrobial Susceptibility Tests (AST), conducted in an in–vitro assay, showed a hydrophilic character of the films and a protection against bacterial growth, making the process a promising path for the production of surface protective polymeric films.

Freestanding nanomaterials for subcellular neuronal interfaces

Current technological advances in neural probing and modulation have enabled an extraordinary glimpse into the intricacies of the nervous system. Particularly, nanomaterials are proving to be an incredibly versatile platform for neurological applications owing to their biocompatibility, tunability, highly specific targeting and sensing, and long-term chemical stability. Among the most desirable nanomaterials for neuroengineering, freestanding nanomaterials are minimally invasive and remotely controlled. This review outlines the most recent developments of freestanding nanomaterials that operate on the neuronal interface. First, the different nanomaterials and their mechanisms for modulating neurons are explored to provide a basis for how freestanding nanomaterials operate. Then, the three main applications of subcellular neuronal engineering-modulating neuronal behavior, exploring fundamental neuronal mechanism, and recording neuronal signal-are highlighted with specific examples of current advancements. Finally, we conclude with our perspective on future nanomaterial designs and applications.

Overcoming barriers in photodynamic therapy harnessing nano-formulation strategies

Photodynamic therapy (PDT) has been extensively investigated for decades for tumor treatment because of its non-invasiveness, spatiotemporal selectivity, lower side-effects, and immune activation ability. It can be a promising treatment modality in several medical fields, including oncology, immunology, urology, dermatology, ophthalmology, cardiology, pneumology, and dentistry. Nevertheless, the clinical application of PDT is largely restricted by the drawbacks of traditional photosensitizers, limited tissue penetrability of light, inefficient induction of tumor cell death, tumor resistance to the therapy, and the severe pain induced by the therapy. Recently, various photosensitizer formulations and therapy strategies have been developed to overcome these barriers. Significantly, the introduction of nanomaterials in PDT, as carriers or photosensitizers, may overcome the drawbacks of traditional photosensitizers. Based on this, nanocomposites excited by various light sources are applied in the PDT of deep-seated tumors. Modulation of cell death pathways with co-delivered reagents promotes PDT induced tumor cell death. Relief of tumor resistance to PDT with combined therapy strategies further promotes tumor inhibition. Also, the optimization of photosensitizer formulations and therapy procedures reduces pain in PDT. Here, a systematic summary of recent advances in the fabrication of photosensitizers and the design of therapy strategies to overcome barriers in PDT is presented. Several aspects important for the clinical application of PDT in cancer treatment are also discussed.

Supramolecular Polymer Nanocomposites for Biomedical Applications

Polymer nanocomposites, a class of innovative materials formed by polymer matrixes and nanoscaled fillers (e.g., carbon-based nanomaterials, inorganic/semiconductor nanoparticles, metal/metal-oxide nanoparticles, polymeric nanostructures, etc.), display enhanced mechanical, optoelectrical, magnetic, catalytic, and bio-related characteristics, thereby finding a wide range of applications in the biomedical field. In particular, the concept of supramolecular chemistry has been introduced into polymer nanocomposites, which creates myriad “smart” biomedical materials with unique physicochemical properties and dynamic tunable structures in response to diverse external stimuli. This review aims to provide an overview of the chemical composition, morphological structures, biological functionalities, and reinforced performances of supramolecular polymer nanocomposites. Additionally, recent advances in biomedical applications such as therapeutic delivery, bioimaging, and tissue engineering are also discussed, especially their excellent properties leveraged in the development of multifunctional intelligent biomedical materials.

Fabrication and Characterization of Polysorbate/Ironmolybdophosphate Nanocomposite: Ion Exchange Properties and pH-responsive Drug Carrier System for Methylcobalamin

Background:

Nanocomposites are of great interest due to their competency to show multifunctional properties. They have been recently given much attention due to their credibility to offer the synergistic feature of organic material with those of inorganic constituents. Different types of nanocomposites have been prepared to date and are being used for different applications. The delivery of drugs in the human body at a particular site was one of the major problems in the medicinal field. The nanocomposite formulations can be used to provide controlled release and they can be combined with ligands for targeted drug delivery. Applications of the nanocomposites as ion exchangers are also increasing at a faster rate. Due to this, they help in the softening of the water. They can also be easily recharged by washing them with a solution containing a high concentration of sodium ions. In the present paper, we have worked on the synthesis and applications of the polysorbate/ironmolybdophosphate (PS/FMP) nanocomposite.

Methods:

Polysorbate/ironmolybdophosphate (PS/FMPS) was synthesized by co-precipitation method in the presence of polysorbate. The material was well characterized using X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy, (FTIR) scanning transmission microscopy (SEM), and transmission electron microscopy (TEM). Physicochemical properties of material were studied in detail. Drug delivery behavior of polysorbate/ironmolybdophosphate was investigated by using methylcobalamin as a test drug.

Results:

The polysorbate/ironmolybdophosphate nanocomposite show enhanced Na+ ion exchange capacity of 2.1 meq/g. It has been revealed that PS/FMP nanocomposite was thermally stable as it retained the ion exchange capacity of 40.4 % at 400°C. An optimum concentration of sodium nitrate (eluent) was found to be 1.0 M for the complete removal of H+ ions from the PS/FMP column. The optimum volume of sodium nitrate (eluent) was found to be 230 mL. The FTIR spectra showed the changes in intensities of characteristic peaks in PS/FMP and in drug loaded on PS/FMP nanocomposite. The characteristic peak at 1043-1061 cm-1 was observed for ionic phosphate stretching, 560-567 cm-1 for iron group and 959 cm-1 due to molybdate present in the material. The additional peak at 3390 cm-1 and 1711 cm-1 were due to -OH and C=O stretching due to the presence of these groups in the structure of polysorbate. The peak present at 430 cm-1 might be due to the presence of Co-O stretching of methylcobalamin. The XRD results confirmed the semicrystalline structure of FMP and PS/FMP. Scanning electron micrographs results revealed the beaded surface of FMP changes to fibrous surface in case of PS/FMP nanocomposite. The TEM images indicate the appearance of smooth surfactant layer on the surface of FMP. The size of the nanocomposite is between 10- 70 nm. The drug loading efficiency and encapsulation efficiency were found to be 35.2%. and 60.4%, respectively. The cumulative drug release of methylcobalamin was studied for the PS/FMP nanocomposite. The order of drug release was found to be pH 9.4 (54.6%) > pH 7.4 (46.4%) > saline (pH 5.7) (36.2%) > pH 2.2 (33.9%). The release at pH 9.4 was higher. As the pH of medium changes from acidic to basic i.e. 2.2 - 9.4, there is an appreciable increase in drug release from the PS/FMP nanocomposite due to the presence of more OH- ions resulting in neutralization of cationic nanocomposite and thus increasing the rate of drug release by ion exchange process and matrix deterioration.

:

The novel nanocomposite PS/FMP has been synthesized by a simple co-precipitation method. The increase in Na+ ion exchange capacity for nanocomposite is due to the binding of organic part (Polysorbate) with inorganic ironmolybdophosphate. The physiochemical properties of PS/FMP were found to be superior. Fourier transform infrared spectra of PS/FMP and drug loaded PS/FMP confirmed the formation of materials. The SEM results indicated the surface of synthesized FMP is bead-like appearance whereas the beaded surface of FMP changes to fibrous surface on the addition of polysorbate thus indicated the fabrication of nanocomposite. The cumulative drug release of methylcobalamin was studied and the order of drug release was found to be pH 9.4 > pH 7.4 > saline (pH 5.7) > pH 2.2. Thus PS/FMP is a promising multifunctional nanocomposite.

Hollow Alginate-Poly-L-Lysine-Alginate Microspheres Promoted an Epithelial-Mesenchymal Transition in Human Colon Adenocarcinoma Cells

Purpose: Today, there is an urgent need to develop a three-dimentional culture systems mimicking native in vivo condition in order to screen potency of drugs and possibly any genetic alterations in tumor cells. Due to the existence of limitations in animal models, the development of three dimensional systems is highly recommended. To this end, we encapsulated human colon adenocarcinoma cell line HT29 with alginate-poly-L-lysine (Alg-PLL) microspheres and the rate of epithelial-mesenchymal transition was monitored. Methods: Cells were randomly divided into three groups; control, alginate and Alg-PLL. To encapsulate cells, we mixed HT-29 cells (1 × 10⁶ ) with 1 mL of 0.05% PLL and 1% Alg mixture and electrosprayed into CaCl2 solution by using a high-voltage power. Cells from all groups were maintained at 37˚C in a humidified atmosphere containing 5% CO₂ for 7 days. Cell viability was assessed by MTT assay. To monitor the stemness feature, we measured the transcription of genes such as Snail, Zeb, and Vimentin by using real-time PCR analysis. Results: Addition of PLL to Alg in a hallowed state increased the cell survival rate compared to the control and Alg groups (P<0.05). Cells inside Alg-PLL tended to form microcellular aggregates while in Alg microspheres an even distribution of HT-29 cells was found. Real-time PCR analysis showed the up-regulation of Snail, Zeb, and Vimentin in Alg-PLL microspheres compared to the other groups, showing the acquisition of stemness feature (P<0.05). Conclusion: This study showed that hallow Alg-PLL microspheres increased the epithelialmesenchymal transition rate after 7 days in in vitro condition. Such approaches could be touted as appropriate in vitro models for drug screening.

Nanoconjugation and Encapsulation Strategies for Improving Drug Delivery and Therapeutic Efficacy of Poorly Water-Soluble Drugs

Nanoconjugations have been demonstrated to be a dominant strategy for drug delivery and biomedical applications. In this review, we intend to describe several strategies for drug formulation, especially to improve the bioavailability of poorly water-soluble molecules for future application in the therapy of numerous diseases. The context of current studies will give readers an overview of the conjugation strategies for fabricating nanoparticles, which have expanded from conjugated materials to the surface conjugation of nanovehicles. Moreover, nanoconjugates for theranostics are also discussed and highlighted. Overall, these state-of-the-art conjugation methods and these techniques and applications for nanoparticulate systems of poorly water-soluble drugs will inspire scientists to explore and discover more productive techniques and methodologies for drug development.

Comparative Study of the Antimicrobial Effect of Nanocomposites and Composite Based on Poly(butylene adipate-co-terephthalate) Using Cu and Cu/Cu2O Nanoparticles and CuSO4

Nanocomposites and a composite based on poly(butylene adipate-co-terephthalate) (PBAT) were synthesized using commercial copper nanoparticles (Cu-NPs), copper/cuprous oxide nanoparticles (Cu|Cu₂O-NPs), and copper sulfate (CuSO₄), respectively. The Cu|Cu₂O-NPs were synthesized using chemical reduction and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The synthesis of Cu|Cu₂O-NPs yielded a mixture of Cu and Cu₂O, with metal Cu having a spherical morphology of approximately 40 nm in diameter and Cu₂O with a diameter of 150 nm. To prepare the nanocomposites (NCs) and the composite material (MC), the NPs and the CuSO₄ salt were incorporated into the PBAT matrix in concentrations of 1, 3, and 5% p/p via an ex situ method. Fourier transform infrared spectroscopy (FTIR), a tensile test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and agar diffusion assays were used for structural, thermomechanical, and antimicrobial characterization. Results showed that the reinforcements did not modify the chemical structure of the PBAT and only slightly increased the percentage of crystallization. The mechanical and thermal properties of the PBAT did not change much with the addition of fillers, except for a slight increase in tensile strength and thermal stability, respectively. The agar diffusion antimicrobial assays showed that the NCs and MCs had good inhibitory responses against the nonresistant strains Enterococcus faecalis, Streptococcus mutans, and Staphylococcus aureus. The MCs based on CuSO₄ had the highest biocidal effect, even against the resistant bacteria Acinetobacter baumannii.

Synthesis and Characterization of Acetic Acid-Doped Polyaniline and Polyaniline⁻Chitosan Composite

Polyaniline–chitosan (PAni–Cs) composite films were synthesized using a solution casting method with varying PAni concentrations. Polyaniline powders used in the composite synthesis were polymerized using acetic acid as the dopant media. Raman spectroscopy revealed that the PAni powders synthesized using hydrochloric acid and acetic acid did not exhibit significant difference to the chemical features of PAni, implying that PAni was formed in varying concentrations of the dopant media. The presence of agglomerated particles on the surface of the Cs composite, which may have been due to the presence of PAni powders, was observed with scanning electron microscope–energy dispersive X-ray spectroscopy (SEM–EDX). Ultraviolet–visible (UV–Vis) spectroscopy further showed the interaction of PAni with Cs where the Cs characteristic peak shifted to a higher wavelength. Cell viability assay also revealed that the synthesized PAni–Cs composites were nontoxic and may be utilized for future biomedical applications.

Self-assembly of quaternary ammonium gemini surfactants in cyclohexane upon reinforcement by simple counterions

The quaternary ammonium gemini surfactants 12-s-12 (s = 2, 6, and 10) can produce homogeneous cyclohexane solutions with the assistance of salts, sodium benzoate (NaBez), sodium salicylate (NaSal), or sodium 2-bromoethanesulphonate (NaBres). In these samples, 12-s-12/salt formed aggregates and their structures were assigned by SAXS measurements together with POM observations. Among the three salts, both NaBez and NaBres had similar effects on assisting aggregate formation, but NaSal favoured the generation of aggregates of 12-s-12 with lower interface curvature. For example, both 12-2-12/NaBez and 12-2-12/NaBres formed an I₂ liquid crystalline (LC) phase with an Fm3m structure, but 12-2-12/NaSal generated a H₂ LC phase. Both 12-6-12/NaBez and 12-6-12/NaBres generated a H₂ LC phase, while 12-6-12/NaSal yielded both H₂ and V₂ phases with Pn3m symmetry, both of which co-existed in solution. The special effect of NaSal was attributed to its ortho-hydroxyl in the benzene ring. This favoured the formation of intermolecular hydrogen bonds among the NaSal molecules attracted to the quaternary ammonium head of 12-s-12. The water molecules joined between the NaSal molecules to build hydrogen-bonding bridges, which further increased the size of the 12-s-12 head. This benefited the formation of aggregates with lower surface curvature. In the systems of both NaBez and NaBres, the spacer length of the gemini surfactants dominated the morphology of the formed aggregates, wherein the effect of the salt was significantly weaker. Finally, the visco-elasticity of samples with similar aggregates was measured and the rheological behaviour discussed.

12-s-12/salt formed various reverse aggregates in cyclohexane dependent upon both spacer length and salt effects.