Synthesis, self-assembly and drug release behaviors of pH-responsive copolymers ethyl cellulose-graft-PDEAEMA through ATRP

Pharmaceutical Applications of Biomass Polymers: Review of Current Research and Perspectives

Polymers derived from natural biomass have emerged as a valuable resource in the field of biomedicine due to their versatility. Polysaccharides, peptides, proteins, and lignin have demonstrated promising results in various applications, including drug delivery design. However, several challenges need to be addressed to realize the full potential of these polymers. The current paper provides a comprehensive overview of the latest research and perspectives in this area, with a particular focus on developing effective methods and efficient drug delivery systems. This review aims to offer insights into the opportunities and challenges associated with the use of natural polymers in biomedicine and to provide a roadmap for future research in this field.

Degradable Polymeric Bio(nano)materials and Their Biomedical Applications: A Comprehensive Overview and Recent Updates

Degradable polymers (both biomacromolecules and several synthetic polymers) for biomedical applications have been promising very much in the recent past due to their low cost, biocompatibility, flexibility, and minimal side effects. Here, we present an overview with updated information on natural and synthetic degradable polymers where a brief account on different polysaccharides, proteins, and synthetic polymers viz. polyesters/polyamino acids/polyanhydrides/polyphosphazenes/polyurethanes relevant to biomedical applications has been provided. The various approaches for the transformation of these polymers by physical/chemical means viz. cross-linking, as polyblends, nanocomposites/hybrid composites, interpenetrating complexes, interpolymer/polyion complexes, functionalization, polymer conjugates, and block and graft copolymers, are described. The degradation mechanism, drug loading profiles, and toxicological aspects of polymeric nanoparticles formed are also defined. Biomedical applications of these degradable polymer-based biomaterials in and as wound dressing/healing, biosensors, drug delivery systems, tissue engineering, and regenerative medicine, etc., are highlighted. In addition, the use of such nano systems to solve current drug delivery problems is briefly reviewed.

The synthesis of multifunctional cellulose graft alternating copolymers of 3,4-dihydrocoumarin and epoxides in DBU/DMSO/CO2 solvent system

Cellulose graft copolymers having well-defined structures could incorporate the characteristics of both the cellulose skeleton and side chains, providing a new method for the preparation functionalised cellulose derivatives. Herein, a series of multifunctional cellulose grafted, alternating 3,4-dihydrocoumarin (DHC) and epoxide (EPO) copolymers (cell-g-P(DHC-alt-EPO)) were prepared in a metal-free DBU/DMSO/CO2 solvent system without adding additional catalyst. Four examples of cell-g-P(DHC-alt-EPO) with tunable thermal and optical properties were synthesized by copolymerization of DHC with styrene oxide (SO), propylene oxide (PO), cyclohexene oxide (CHO) or furfuryl glycidyl ether (FGE) onto cellulose. The nonconjugated cell-g-P(DHC-alt-EPO) showed UV absorption properties with the maximum absorption peak at 282 nm and 295 nm and photoluminescence performance. A clustering-triggered emission mechanism was confirmed and consistent with DFT theoretical calculations. In DMSO solution, the copolymer (DHCSO5) with DP of 11.64 showed ACQ behaviour as the concentration increased. In addition, DHCSO5 had good antioxidant capacity with an instantaneous radical scavenging activity of 2,2-diphenyl-1-picrylhydrazine (DPPH) up to 65 % at a concentration of 40 mg/ ml and increased to 100 % after 30 min. Thus, the multifunctional cell-g-P(DHC-alt-EPO) materials had a variety of potential applications in the fields of fluorescent printing, bio-imaging, UV- shielding and antioxidants.

Plant-derived polyphenolic compounds: nanodelivery through polysaccharide-based systems to improve the biological properties

Plant-derived polyphenols are naturally occurring compounds widely distributed in plants. They have received greater attention in the food and pharmaceutical industries due to their potential health benefits, reducing the risk of some chronic diseases due to their antioxidant, anti-inflammatory, anticancer, cardioprotective, and neuro-action properties. Polyphenolic compounds orally administered can be used as adjuvants in several treatments but with restricted uses due to chemical instability. The review discusses the different structural compositions of polyphenols and their influence on chemical stability. Despite the potential and wide applications, there is a need to improve the delivery of polyphenolics to target the human intestine without massive chemical modifications. Oral administration of polyphenols is unfeasible due to instability, low bioaccessibility, and limited bioavailability. Nano-delivery systems based on polysaccharides (starch, pectin, chitosan, and cellulose) have been identified as a viable option for oral ingestion, potentiate biological effects, and direct-controlled delivery in specific tissues. The time and dose can be individualized for specific diseases, such as intestinal cancer. This review will address the mechanisms by which polysaccharides-based nanostructured systems can protect against degradation and enhance intestinal permeation, oral bioavailability, and the potential application of polysaccharides as nanocarriers for the controlled and targeted delivery of polyphenolic compounds.

Cellulose Amphiphilic Materials: Chemistry, Process and Applications

In the last decade, amphiphilic cellulose (AC) is emerging as attractive biomaterial for different therapeutic use, due to its unique chemical and physical properties. Using it as alternative to synthetic polymers, AC opens up new avenues to prepare new bio-sustainable materials with low impact in the cellular environment. Herein, most recent methods to synthesize and processing AC materials from different sources—i.e., cellulose nanofibers, bacterial cellulose, cellulose derivatives—will be discussed. By an accurate optimization of morphology and surface chemistry, it is possible to develop innovative amphiphilic platforms, promising for a wide range of biomedical applications, from drug delivery to molecular/particle adsorption.

Synthesis of an amphiphilic copolymer using biopolymer-dextran via combination of ROP and RAFT techniques

The ring-opening polymerization (ROP) and reversible addition−fragmentation chain-transfer polymerization (RAFT) are efficient synthetic approaches to develop self-assembled copolymers with narrow dispersity (Ɖ). The aim of this work is to develop...

Wood-Derived Functional Polymeric Materials

In recent years, tremendous efforts have been dedicated to developing wood-derived functional polymeric materials due to their distinctive properties, including environmental friendliness, renewability, and biodegradability. Thus, the uniqueness of the main components in wood (cellulose and lignin) has attracted enormous interest for both fundamental research and practical applications. Herein, the emerging field of wood-derived functional polymeric materials fabricated by means of macromolecular engineering is reviewed, covering the basic structures and properties of the main components, the design principle to utilize these main components, and the resulting wood-derived functional polymeric materials in terms of elastomers, hydrogels, aerogels, and nanoparticles. In detail, the natural features of wood components and their significant roles in the fabrication of materials are emphasized. Furthermore, the utilization of controlled/living polymerization, click chemistry, dynamic bonds chemistry, etc., for the modification is specifically discussed from the perspective of molecular design, together with their sequential assembly into different morphologies. The functionalities of wood-derived polymeric materials are mainly focused on self-healing and shape-memory abilities, adsorption, conduction, etc. Finally, the main challenges of wood-derived functional polymeric materials fabricated by macromolecular engineering are presented, as well as the potential solutions or directions to develop green and scalable wood-derived functional polymeric materials.

Cellulose-based thermo-enhanced fluorescence micelles

Recently, cellulose-based stimuli-responsive nanomaterials have received significant attention because of its natural source and biocompatibility. In this study, cellulose-graft-poly(nisopropylacrylamide)-co-2-methyl-acrylic acid 2-carbazol-9-yl-ethyl ester (cellulose-g-(PNIPAAm&PCz)) block polymers were successfully synthesized by homogeneous atom transfer radical polymerization (ATRP) in LiCl/N,N-dimethylacetamide (DMAc) dissolution system. The block polymers showed different properties due to the different PCz content. The block polymer with low PCz content (cellulose-g-(PNIPAAm&PCz)1) was dispersed in water at 25 °C and self-assembled into micelles at 37 °C. On the other hand, the block polymer with high PCz content (cellulose-g-(PNIPAAm&PCz)2) was dissolved in DMF, THF, DMSO firstly, and dialyzed at 25 °C, 37 °C and 60 °C respectively to obtain the micelles. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) indicated that the distribution range of micelles formed by cellulose-g-(PNIPAAm&PCz)1 was narrower than cellulose-g-(PNIPAAm&PCz)2. And the sizes of the micelles formed by cellulose-g-(PNIPAAm&PCz)2 had little difference under different solvents, but became bigger with the temperature increased. The micelles displayed thermo-enhanced fluorescence due to the thermal-driven chain dehydration of the grafted PNIPAAm brushes, which is contrary to the decrease of the fluorescence of the monomer when the temperature increased. The results provided a potential for the application of cellulose-based stimuli-responsive micelles in the field of drug delivery and fluorescent probes.

Coumarin-Containing Light-Responsive Carboxymethyl Chitosan Micelles as Nanocarriers for Controlled Release of Pesticide

Currently, controlled release formulations (CRFs) of pesticides in response to biotic and/or abiotic stimuli have shown great potential for providing “on-demand” smart release of loaded active ingredients. In this study, amphiphilic biopolymers were prepared by introducing hydrophobic (7-diethylaminocoumarin-4-yl)methyl succinate (DEACMS) onto the main chain of hydrophilic carboxymethylchitosan (CMCS) via the formation of amide bonds which were able to self-assemble into spherical micelles in aqueous media and were utilized as light-responsive nanocarriers for the controlled release of pesticides. FTIR and NMR characterizations confirmed the successful synthesis of the CMCS-DEACMS conjugate. The critical micelle concentration (CMC) decreased with the increase in the substitution of DEACMS on CMCS, which ranged from 0.013 to 0.042 mg/mL. Upon irradiation under simulated sunlight, the hydrodynamic diameter, morphology, photophysical properties and photolysis were researched by means of dynamic light scattering (DLS), transmission electron microscopy (TEM), UV-vis absorption spectroscopy and fluorescence spectroscopy. Moreover, 2,4-dichlorophenoxyacetic acid (2,4-D) was used as a model pesticide and encapsulated into the CMCS-DEACMS micelles. In these micelle formulations, the release of 2,4-D was promoted upon simulated sunlight irradiation, during which the coumarin moieties were cleaved from the CMCS backbone, resulting in a shift of the hydrophilic–hydrophobic balance and destabilization of the micelles. Additionally, bioassay studies suggested that this 2,4-D contained which micelles showed good bioactivity on the target plant without harming the nontarget plant. Thereby, the light-responsive CMCS-DEACMS micelles bearing photocleavable coumarin moieties provide a smart delivery platform for agrochemicals.

Stimuli-Responsive Rifampicin-Based Macromolecules

This paper presents the modification of the antibiotic rifampicin by an anionic polyelectrolyte using a simplified electrochemically mediated atom transfer radical polymerization (seATRP) technique to receive stimuli-responsive polymer materials. Initially, a supramolecular ATRP initiator was prepared by an esterification reaction of rifampicin hydroxyl groups with α-bromoisobutyryl bromide (BriBBr). The structure of the initiator was successfully proved by nuclear magnetic resonance (1H and 13C NMR), Fourier-transform infrared (FT-IR) and ultraviolet-visible (UV-vis) spectroscopy. The prepared rifampicin-based macroinitiator was electrochemically investigated among various ATRP catalytic complexes, by a series of cyclic voltammetry (CV) measurements, determining the rate constants of electrochemical catalytic (EC') process. Macromolecules with rifampicin core and hydrophobic poly (n-butyl acrylate) (PnBA) and poly(tert-butyl acrylate) (PtBA) side chains were synthesized in a controlled manner, receiving polymers with narrow molecular weight distribution (Mw/Mn = 1.29 and 1.58, respectively). "Smart" polymer materials sensitive to pH changes were provided by transformation of tBA into acrylic acid (AA) moieties in a facile route by acidic hydrolysis. The pH-dependent behavior of prepared macromolecules was investigated by dynamic light scattering (DLS) determining a hydrodynamic radius of polymers upon pH changes, followed by a control release of quercetin as a model active substance upon pH changes.

Dopamine-loaded poly (butyl cyanoacrylate) nanoparticles reverse behavioral deficits in Parkinson’s animal models

Aim: Parkinson's disease (PD) is a neurological disorder resulting from decreased dopamine (DA) secretion in the brain, which reflects impaired motor function. Thus, a drug-delivery system for releasing DA into the brain would be of crucial importance. Materials & methods: We herein examined the in vivo drug efficiency of novel poly-butyl-cyanoacrylate nanoparticles loaded with DA (DA-PBCA NPs). Results & conclusion: The NPs were able to pass through the blood–brain barrier and improve brain structure and function in the PD animal models. Moreover, we found a reduced α-synucleinopathy in the animal model brains after the NPs administration. Thus, the NPs seem to be a reliable DA delivery system for treating PD patients.

Recent advances in celluloses and their hybrids for stimuli-responsive drug delivery

The limitations of existing drug delivery systems (DDS) such as non-specific bio-distribution and poor selectivity have led to the exploration of a variety of carrier platforms to facilitate highly desirable and efficient drug delivery. Stimuli-responsive DDS are one of the most versatile and innovative approach to steer the compounds to the intended sites by exploiting their responsiveness to a range of various triggers. Preparation of stimuli-responsive DDS using celluloses and their derivatives offer a remarkable advantage over conventional polymer materials. In this review, we highlight on state-of-art progress in developing cellulose/cellulose hybrid stimuli-responsive DDS, which covers the preparation techniques, physicochemical properties, basic principles and, mechanisms of stimuli effect on drug release from various types of cellulose based carriers, through recent innovative investigations. Attention has been paid to endogenous stimuli (pH, temperature, redox gradient and ionic-strength) responsive DDS and exogenous stimuli (light, magnetic field and electric field) responsive DDS, where the cellulose-based materials have been extensively employed. Furthermore, the current challenges and future prospects of these DDS are also discussed at the end.

Fabrication and Characterization of Thermal-responsive Biomimetic Small-scale Shape Memory Wood Composites with High Tensile Strength, High Anisotropy

Intelligent responsive materials have become one of the most exciting fields in the research of new materials in the past few decades due to their practical and potential applications in aerospace, biomedicine, textile, electronics, and other relative fields. Here, a novel thermal-responsive biomimetic shape memory wood composite is fabricated utilizing polycaprolactone-based (PCL) shape-memory polymer to modify treated-wood. The shape memory wood inherits visual characteristics and the unique three-dimension structure of natural wood that endows the shape memory wood (SMW) with outstanding tensile strength (10.68 MPa) at room temperature. In terms of shape memory performance, the shape recovery ratio is affected by multiple factors including environment temperature, first figuration angle, cycle times, and shows different variation tendency, respectively. Compared with shape recovery ratio, the shape fixity ratio (96%) is relatively high and stable. This study supplies more possibilities for the functional applications of wood, such as biomimetic architecture, self-healing wood veneering, and intelligent furniture.

Review of Stimuli-Responsive Polymers in Drug Delivery and Textile Application

This review describes some commercially available stimuli-responsive polymers of natural and synthetic origin, and their applications in drug delivery and textiles. The polymers of natural origin such as chitosan, cellulose, albumin, and gelatin are found to show both thermo-responsive and pH-responsive properties and these features of the biopolymers impart sensitivity to act differently under different temperatures and pH conditions. The stimuli-responsive characters of these natural polymers have been discussed in the review, and their respective applications in drug delivery and textile especially for textile-based transdermal therapy have been emphasized. Some practically important thermo-responsive polymers such as pluronic F127 (PF127) and poly(N-isopropylacrylamide) (pNIPAAm) of synthetic origin have been discussed in the review and they are of great importance commercially because of their in situ gel formation capacity. Some pH-responsive synthetic polymers have been discussed depending on their surface charge, and their drug delivery and textile applications have been discussed in this review. The selected stimuli-responsive polymers of synthetic origin are commercially available. Above all, the applications of bio-based or synthetic stimuli-responsive polymers in textile-based transdermal therapy are given special regard apart from their general drug delivery applications. A special insight has been given for stimuli-responsive hydrogel drug delivery systems for textile-based transdermal therapy, which is critical for the treatment of skin disease atopic dermatitis.

A glimpse of biodegradable polymers and their biomedical applications

Over the past two decades, biodegradable polymers (BPs) have been widely used in biomedical applications such as drug carrier, gene delivery, tissue engineering, diagnosis, medical devices, and antibacterial/antifouling biomaterials. This can be attributed to numerous factors such as chemical, mechanical and physiochemical properties of BPs, their improved processibility, functionality and sensitivity towards stimuli. The present review intended to highlight main results of research on advances and improvements in terms of synthesis, physical properties, stimuli response, and/or applicability of biodegradable plastics (BPs) during last two decades, and its biomedical applications. Recent literature relevant to this study has been cited and their developing trends and challenges of BPs have also been discussed.

A review of natural polysaccharides for drug delivery applications: Special focus on cellulose, starch and glycogen

Natural polysaccharides are renewable with a high degree of biocompatibility, biodegradability, and ability to mimic the natural extracellular matrix (ECM) microenvironment. Comprehensive investigations of polysaccharides are essential for our fundamental understanding of exploiting its potential as bio-composite, nano-conjugate and in pharmaceutical sectors. Polysaccharides are considered to be superior to other polymers, for its ease in tailoring, bio-compatibility, bio-activity, homogeneity and bio-adhesive properties. The main focus of this review is to spotlight the new advancements and challenges concerned with surface modification, binding domains, biological interaction with the conjugate including stability, polydispersity, and biodegradability. In this review, we have limited our survey to three essential polysaccharides including cellulose, starch, and glycogen that are sourced from plants, microbes, and animals respectively are reviewed. We also present the polysaccharides which have been extensively modified with the various types of conjugates for combating last-ditch pharmaceutical challenges.

Combining Cellulose and Cyclodextrins: Fascinating Designs for Materials and Pharmaceutics

Cellulose and cyclodextrins possess unique properties that can be tailored, combined, and used in a considerable number of applications, including textiles, coatings, sensors, and drug delivery systems. Successfully structuring and applying cellulose and cyclodextrins conjugates requires a deep understanding of the relation between structural, and soft matter behavior, materials, energy, and function. This review focuses on the key advances in developing materials based on these conjugates. Relevant aspects regarding structural variations, methods of synthesis, processing and functionalization, and corresponding supramolecular properties are presented. The use of cellulose/cyclodextrin conjugates as intelligent platforms for applications in materials science and pharmaceutical technology is also outlined, focusing on drug delivery, textiles, and sensors.

A CO2-tunable plasmonic nanosensor based on the interfacial assembly of gold nanoparticles on diblock copolymers grafted from gold surfaces

A general stepwise strategy for the fabrication of CO2-tunable plasmonic nanosensors was described for the first time, based on gold surface functionalization by CO2-responsive poly(N,N-diethylaminoethyl methacrylate) (PDEAEMA) brushes via a surface-initiated atom transfer radical polymerization (SI-ATRP) method, then the extremity of PDEAEMA was functionalized by linking the polyacrylamide (PAAm) brushes via ATRP, where they were assembled with gold nanoparticles (AuNPs) efficiently by altering the deposition time. The swelling-shrinking states of the PDEAEMA brushes can be tuned just by passing CO2 and N2 through a solution alternately. The unique plasmonic surface-enhanced Raman scattering (SERS) sensing properties of these stimulable substrates were investigated using 4-mercaptophenol (4MPh) as a molecular probe. When alternating CO2 and N2 bubbling in the water solution, the reversible switching of the SERS signals was complete. By in situ contact-mode atomic force microscopy, the thickness of the polymer layer was observed to be 26 nm in CO2 saturated water, and after N2 bubbling to remove CO2 it decreased to 15 nm, causing the AuNPs to move near to the gold surface. Meanwhile, the distance between the nearby AuNPs becomes smaller, and the surface coverage (φ) of the AuNPs increased from 27% to 35%. The reported CO2-responsive plasmonic nanosensor provided a dynamic SERS platform, with reversible regulation for electromagnetic coupling between the AuNPs and the gold surface, and between nearby AuNPs.

Synthesis of triblock copolymeric micelle based on poly (ethylene glycol) and poly (vinyl acetate) through reversible addition-fragmentation chain transfer polymerization

HYPOTHESIS

Polymeric micelles are fabricated by the self-aggregation of amphiphilic polymers in aqueous medium. Amphiphilic block copolymers consist of hydrophobic and hydrophilic blocks. The hydrophilic blocks form corona, while hydrophobic blocks produce core of the micelle.

EXPERIMENTS

In the present manuscript, a triblock copolymer derived from poly (ethylene glycol) and poly (vinyl acetate) (PVAc-b-PEG₂₀₀-b-PVAc) has been prepared via reversible addition-fragmentation chain transfer polymerization. Its structural properties as well as micellar stability have been studied and application as dye carrier has been discussed in details.

FINDINGS

The GPC analysis shows the low polydispersity of the developed copolymer that signifies the controlled nature of polymerization. The copolymer demonstrates long-term micellar stability, which has been determined by dynamic light scattering (DLS) analysis. The block copolymer reveals excellent pH-triggered release behavior of loaded Nile red, which ascertained the dye carrier feature of PVAc-b-PEG₂₀₀-b-PVAc.

Versatile Functionalization of Polysaccharides via Polymer Grafts: From Design to Biomedical Applications

Because of their biocompatibility, biodegradability, and unique bioactive properties, polysaccharides have been recognized and directly applied as excellent candidates for various biomedical applications. In order to introduce more functionalities onto polysaccharides, various modification methods were applied to improve the physical-chemical and biochemical properties. Grafting polysaccharides with functional polymers with limited reaction sites maximizes the structural integrity. To the best of our knowledge, great efforts have been made by scientists across the world, including our research group, to explore different strategies for the synthesis and design of controllable polymer-grafted polysaccharides. By the application of some reasonable strategies, a series of polymer-grafted polysaccharides with satisfactory biocharacteristics were obtained. The first strategy involves facile modification of polysaccharides with living radical polymerization (LRP). Functionalized polysaccharides with diverse grafts can be flexibly and effectively achieved. The introduced grafts include cationic components for nuclei acid delivery, PEGylated and zwitterionic moieties for shielding effects, and functional species for bioimaging applications as well as bioresponsive drug release applications. The second synthetic model refers to biodegradable polymer-grafted polysaccharides prepared by ring-opening polymerization (ROP). Inspired by pathways to introduce initiation sites onto polysaccharides, the use of amine-functionalized polysaccharides was explored in-depth to trigger ROP of amino acids. A series of poly(amino acid)-grafted polysaccharides with advanced structures (including linear, star-shaped, and comb-shaped copolymers) were developed to study and optimize the structural effects. In addition, biodegradable polyester-grafted polysaccharides were prepared and utilized for drug delivery. Another emerging strategy was to design polysaccharide-based assemblies with supramolecular structures. A variety of assembly techniques using non-covalent interactions were established to construct different types of polysaccharide-based assemblies with various bioapplications. On the basis of these strategies, polymer-grafted polysaccharides with controllable functions were reported to be well-suited for different kinds of biomedical applications. The exciting results were obtained from both in vitro and in vivo models. Viewing the rapid growth of this field, the present Account will update the concepts, trends, perspectives, and applications of functionalized polysaccharides, guiding and inspiring researchers to explore new polysaccharide-based systems for wider applications.

Carbohydrate-based amphiphilic nano delivery systems for cancer therapy

Nanoparticles (NPs) are novel drug delivery systems that have been attracting more and more attention in recent years, and have been used for the treatment of cancer, infection, inflammation and other diseases. Among the numerous classes of materials employed for constructing NPs, organic polymers are outstanding due to the flexibility of design and synthesis and the ease of modification and functionalization. In particular, NP based amphiphilic polymers make a great contribution to the delivery of poorly-water soluble drugs. For example, natural, biocompatible and biodegradable products like polysaccharides are widely used as building blocks for the preparation of such drug delivery vehicles. This review will detail carbohydrate based amphiphilic polymeric systems for cancer therapy. Specifically, it focuses on the nature of the polymer employed for the preparation of targeted nanocarriers, the synthetic methods, as well as strategies for the application and evaluation of biological activity. Applications of the amphiphilic polymer systems include drug delivery, gene delivery, photosensitizer delivery, diagnostic imaging and specific ligand-assisted cellular uptake. As a result, a thorough understanding of the relationship between chemical structure and biological properties facilitate the optimal design and rational clinical application of the resulting carbohydrate based nano delivery systems for cancer therapy.