Branched copolymer surfactants impart thermoreversible gelation to LAPONITE® gels

This investigation seeks to integrate LAPONITE® clay gels with thermoresponsive branched copolymer surfactants (BCSs) to develop advanced functional materials with temperature-induced sol-gel behaviour. It is known that a diverse range of molecules adsorb strongly to clays which may be used to control liberation of the species in healthcare applications, and as such the development of polymer/clay hybrid materials which can add function to the native clay behaviour are of great interest. BCS were synthesised with a structure that encompasses poly(ethylene glycol)methacrylate (PEGMA), ethylene glycol dimethacrylate (EGDMA), and dodecanethiol (DDT), conferring versatile and tuneable thermoresponsive attributes. Systematic modulation of the monomer : DDT/initiator ratio was used to facilitate the synthesis of BCS architectures spanning a range of molecular weights. Through application of small-amplitude oscillatory shear (SAOS) rheology and small-angle neutron scattering (SANS) in conjunction with controlled temperature variations, the sol-gel transition dynamics of these nanocomposite materials were elucidated. Complementary insights into the mechanisms underpinning this transition and temperature-induced alterations in the constituents are gleaned through the utilization of SANS techniques employing contrast-matching methodologies to mitigate clay and polymer scattering interference. It is found that heating systems from room- to body- temperature induces self-assembly of BCS in the bulk aqueous phase with concurrent structuration of clay in gel-forming samples with lower number average molecular weight (Mn). SANS study unpicks this phenomenon to find that gelation occurs with concurrent aggregation of BCS in the bulk, inducing clay-clay interactions only in lower Mn BCS systems with large nanoaggregates.

4D Printing of Hydrogels: Innovation in Material Design and Emerging Smart Systems for Drug Delivery

Advancements in the material design of smart hydrogels have transformed the way therapeutic agents are encapsulated and released in biological environments. On the other hand, the expeditious development of 3D printing technologies has revolutionized the fabrication of hydrogel systems for biomedical applications. By combining these two aspects, 4D printing (i.e., 3D printing of smart hydrogels) has emerged as a new promising platform for the development of novel controlled drug delivery systems that can adapt and mimic natural physio-mechanical changes over time. This allows printed objects to transform from static to dynamic in response to various physiological and chemical interactions, meeting the needs of the healthcare industry. In this review, we provide an overview of innovation in material design for smart hydrogel systems, current technical approaches toward 4D printing, and emerging 4D printed novel structures for drug delivery applications. Finally, we discuss the existing challenges in 4D printing hydrogels for drug delivery and their prospects.

Log Poct/SA Predicts the Thermoresponsive Behavior of P(DMA-co-RA) Statistical Copolymers

Polymers that exhibit a lower critical solution temperature (LCST) have been of great interest for various biological applications such as drug or gene delivery, controlled release systems, and biosensing. Tuning the LCST behavior through control over polymer composition (e.g., upon copolymerization of monomers with different hydrophobicity) is a widely used method, as the phase transition is greatly affected by the hydrophilic/hydrophobic balance of the copolymers. However, the lack of a general method that relates copolymer hydrophobicity to their temperature response leads to exhaustive experiments when seeking to obtain polymers with desired properties. This is particularly challenging when the target copolymers are comprised of monomers that individually form nonresponsive homopolymers, that is, only when copolymerized do they display thermoresponsive behavior. In this study, we sought to develop a predictive relationship between polymer hydrophobicity and cloud point temperature (T_CP). A series of statistical copolymers were synthesized based on hydrophilic N,N-dimethyl acrylamide (DMA) and hydrophobic alkyl acrylate monomers, and their hydrophobicity was compared using surface area-normalized octanol/water partition coefficients (Log P_oct/SA). Interestingly, a correlation between the Log P_oct/SA of the copolymers and their T_CPs was observed for the P(DMA-co-RA) copolymers, which allowed T_CP prediction of a demonstrative copolymer P(DMA-co-MMA). These results highlight the strong potential of this computational tool to improve the rational design of copolymers with desired temperature responses prior to synthesis.

Thermoresponsive oligo(ethylene glycol) methyl ether methacrylate based copolymers: composition and comonomer effect

Thermoresponsive polymers based on oligo(ethylene glycol) (OEG) methyl ether methacrylate monomers from unimers to micelles to precipitation.

Liquid Crystalline Properties of Symmetric and Asymmetric End-Grafted Cellulose Nanocrystals

The hydrophilic polymer poly[2-(2-(2-methoxy ethoxy)ethoxy)ethylacrylate] (POEG₃A) was grafted onto the reducing end-groups (REGs) of cellulose nanocrystal (CNC) allomorphs, and their liquid crystalline properties were investigated. The REGs on CNCs extracted from cellulose I (CNC-I) are exclusively located at one end of the crystallite, whereas CNCs extracted from cellulose II (CNC-II) feature REGs at both ends of the crystallite, so that grafting from the REGs affords asymmetrically and symmetrically decorated CNCs, respectively. To confirm the REG modification, several complementary analytical techniques were applied. The grafting of POEG₃A onto the CNC REGs was evidenced by Fourier transform infrared spectroscopy, atomic force microscopy, and the coil-globule conformational transition of this polymer above 60 °C, i.e., its lower critical solution temperature. Furthermore, we investigated the self-assembly of end-tethered CNC-hybrids into chiral nematic liquid crystalline phases. Above a critical concentration, both end-grafted CNC allomorphs form chiral nematic tactoids. The introduction of POEG₃A to CNC-I does not disturb the surface of the CNCs along the rods, allowing the modified CNCs to approach each other and form helicoidal textures. End-grafted CNC-II formed chiral nematic tactoids with a pitch observable by polarized optical microscopy. This is likely due to their increase in hydrodynamic radius or the introduced steric stabilization of the end-grafted polymer.

Exploration of Bioengineered Scaffolds Composed of Thermo-Responsive Polymers for Drug Delivery in Wound Healing

Innate and adaptive immune responses lead to wound healing by regulating a complex series of events promoting cellular cross-talk. An inflammatory response is presented with its characteristic clinical symptoms: heat, pain, redness, and swelling. Some smart thermo-responsive polymers like chitosan, polyvinylpyrrolidone, alginate, and poly(ε-caprolactone) can be used to create biocompatible and biodegradable scaffolds. These processed thermo-responsive biomaterials possess 3D architectures similar to human structures, providing physical support for cell growth and tissue regeneration. Furthermore, these structures are used as novel drug delivery systems. Locally heated tumors above the polymer lower the critical solution temperature and can induce its conversion into a hydrophobic form by an entropy-driven process, enhancing drug release. When the thermal stimulus is gone, drug release is reduced due to the swelling of the material. As a result, these systems can contribute to the wound healing process in accelerating tissue healing, avoiding large scar tissue, regulating the inflammatory response, and protecting from bacterial infections. This paper integrates the relevant reported contributions of bioengineered scaffolds composed of smart thermo-responsive polymers for drug delivery applications in wound healing. Therefore, we present a comprehensive review that aims to demonstrate these systems' capacity to provide spatially and temporally controlled release strategies for one or more drugs used in wound healing. In this sense, the novel manufacturing techniques of 3D printing and electrospinning are explored for the tuning of their physicochemical properties to adjust therapies according to patient convenience and reduce drug toxicity and side effects.

100th Anniversary of Macromolecular Science Viewpoint: The Role of Hydrophobicity in Polymer Phenomena

The seemingly simple notion of the hydrophobic effect can be viewed from multiple angles involving theory, simulation, and experiments. This viewpoint examines five attributes of predictive models to enhance synthetic efforts as well as experimental methods to quantify hydrophobicity. In addition, we compare existing predictive models against experimental data for polymer surface tension, lower critical solution temperature, solution self-assembly morphology, and degradation behavior. Key conclusions suggest that both the Hildebrand solubility parameters (HSPs) and surface area-normalized Log P (Log P SA-1) values provide unique and complementary insights into polymer phenomena. In particular, HSPs appear to better describe bulk polymer phenomena for thermoplastics such as surface tension, while Log P SA-1 values are well-suited for describing and predicting the behavior of polymers in solution.

Well-Defined Thermo-Responsive Copolymers Based on Oligo(Ethylene Glycol) Methacrylate and Pentafluorostyrene for the Removal of Organic Dyes from Water

Thermo-responsive copolymers based on oligo(ethylene glycol) methacrylate (OEGMA, Mn = 300 g/mol) and pentafluorostyrene (PFS), coded PFG, were synthesized by RAFT polymerization, using a trithiocarbonate (CTTPC) as controlling agent. Different molar masses were targeted and dispersities lower than 1.51 were obtained. The thermally triggered self-assembly of the resulting PFG copolymers in water was investigated by dynamic light scattering (DLS). The lower critical solution temperature (LCST) slightly increased with the molecular weight in the 26-30 °C temperature range, whereas the sizes of the intermicellar aggregates formed upon self-assembly tended to decrease with increasing molecular weights (ranging from 1415 to 572 nm). The resulting thermally-induced polymer aggregates were then used to encapsulate and remove organic contaminants from water. Nile Red (NR) and Thiazole yellow G (TYG) were employed as hydrophobic and hydrophilic model contaminants, respectively. Experimental results evidenced that higher molecular weight copolymers removed up to 90% of NR from aqueous solution, corresponding to about 10 mg of dye per g of copolymer, regardless of NR concentration. The removal of TYG was lower with respect to NR, decreasing from about 40% to around 20% with TYG concentration. Finally, the copolymers were shown to be potentially recycled and reused in the treatment of contaminated water.

A facile method to control the phase behavior of hydroxypropyl cellulose

We report a facile chemical method to convert the hydroxyl groups of hydroxypropyl cellulose (HPC) into carbamates. It was achieved by the reaction of HPC with N-methyl carbamoylimidazole, which is a safe and easy to handle replacement for the particularly hazardous reagent methyl isocyanate. Using a series of HPC with a range of molar substitution of hydroxypropyl groups, we synthesized HPC methylcarbamates showing lower critical solution temperature (LCST) in the range between 94 and 15 °C. A linear dependence of LCST versus methylcarbamate degree of substitution is observed. The lower the initial hydroxypropyl content of HPC, the greater the effect of methylcarbamate on the LCST. Surface tension study showed that methylcarbamate modification has an insignificant effect on the hydrophilic-hydrophobic balance of the macromolecules below LCST unless the molecular substitution of hydroxypropyl groups is so low (0.8) that the native cellulose OH groups can react with N-methyl carbamoylimidazole.

Grafting Density Governs the Thermoresponsive Behavior of P(OEGMA-co-RMA) Statistical Copolymers

Thermoresponsive copolymers that exhibit a lower critical solution temperature (LCST) have been exploited to prepare stimuli-responsive materials for a broad range of applications. It is well understood that the LCST of such copolymers can be controlled by tuning molecular weight or through copolymerization of two known thermoresponsive monomers. However, no general methodology has been established to relate polymer properties to their temperature response in solution. Herein, we sought to develop a predictive relationship between polymer hydrophobicity and cloud point temperature (T CP). A series of statistical copolymers were synthesized based on hydrophilic oligoethylene glycol monomethyl ether methacrylate (OEGMA) and hydrophobic alkyl methacrylate monomers and their hydrophobicity was compared using surface area-normalized partition coefficients (log P oct/SA). However, while some insight was gained by comparing T CP and hydrophobicity values, further statistical analysis on both experimental and literature data showed that the molar percentage of comonomer (i.e., grafting density) was the strongest influencer of T CP, regardless of the comonomer used. The lack of dependence of T CP on comonomer chemistry implies that a broad range of functional, thermoresponsive materials can be prepared based on OEGMA by simply tuning grafting density.

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.

UV-Triggered On-Demand Temperature-Responsive Reversible and Irreversible Gelation of Cellulose Nanocrystals

We show ionically cross-linked, temperature-responsive reversible or irreversible hydrogels of anionic cellulose nanocrystals (CNCs) and methacrylate terpolymers by mixing them homogeneously in the initially charge-neutral state of the polymer, which was subsequently switched to be cationic by cleaving side groups by UV irradiation. The polymer is a random terpolymer poly(di(ethylene glycol) methyl ether methacrylate)-rnd-poly(oligo(ethylene glycol) methyl ether methacrylate)-rnd-poly(2-((2-nitrobenzyl)oxycarbonyl)aminoethyl methacrylate), that is, PDEGMA-rnd-POEGMA-rnd-PNBOCAEMA. The PDEGMA and POEGMA repeating units lead to a lower critical solution temperature (LCST) behavior. Initially, homogeneous aqueous mixtures are obtained with CNCs, and no gelation is observed even upon heating to 60 °C. However, upon UV irradiation, the NBOCAEMAs are transformed to cationic 2-aminoethyl methacrylate (AEMA) groups, as 2-nitrobenzaldehyde moieties are cleaved. The resulting mixtures of anionic CNC and cationic PDEGMA-rnd-POEGMA-rnd-PAEMA show gelation for sufficiently high polymer fractions upon heating to 60 °C due to the interplay of ionic interactions and LCST. For short heating times, the gelation is thermoreversible, whereas for long enough heating times, irreversible gels can be obtained, indicating importance of kinetic aspects. The ionic nature of the cross-linking is directly shown by adding NaCl, which leads to gel melting. In conclusion, the optical triggering of the polymer ionic interactions in combination with its LCST phase behavior allows a new way for ionic nanocellulose hydrogel assemblies.

Tunable Thermo-Responsive Copolymers from DEGMA and OEGMA Synthesized by RAFT Polymerization and the Effect of the Concentration and Saline Phosphate Buffer on its Phase Transition

Thermo-responsive polymers and copolymers derivatives of oligo(ethylene glycol) methyl ether methacrylate (Mn = 300 g mol-1) (OEGMA) and di(ethylene glycol) methyl ether methacrylate (DEGMA) have been synthesized by reversible addition fragmentation chain transfer polymerization (RAFT) using 5-amino-4-methyl-4-(propylthiocarbonothioylthio)-5-oxopentanoic acid (APP) as chain transfer agent (CTA). The monomer conversion was evaluated by hydrogen nuclear magnetic resonance (1H-NMR); number average molecular weights (Mn), weight average molecular weight (Mw), and dispersity (Đ) were obtained by gel permeation chromatography (GPC); glass transition temperature (Tg) was evaluated by modulated differential scanning calorimetry (DSC), cloud point temperature (Tcp) was measured and compared by turbidimetry and dynamic light scattering (DLS). The effect of polymer composition and concentration on the Tcp, either in water or in phosphate buffer saline (PBS), was studied. The values of Tcp using PBS were between 3 and 4 °C lower than using water. Results showed an ideal copolymerization behavior; therefore, the Tcp could be tuned by an adequate monomers feed ratio obtaining polymers which may be used in drug delivery and other applications.

Nanocellulose, a Versatile Green Platform: From Biosources to Materials and Their Applications

With increasing environmental and ecological concerns due to the use of petroleum-based chemicals and products, the synthesis of fine chemicals and functional materials from natural resources is of great public value. Nanocellulose may prove to be one of the most promising green materials of modern times due to its intrinsic properties, renewability, and abundance. In this review, we present nanocellulose-based materials from sourcing, synthesis, and surface modification of nanocellulose, to materials formation and applications. Nanocellulose can be sourced from biomass, plants, or bacteria, relying on fairly simple, scalable, and efficient isolation techniques. Mechanical, chemical, and enzymatic treatments, or a combination of these, can be used to extract nanocellulose from natural sources. The properties of nanocellulose are dependent on the source, the isolation technique, and potential subsequent surface transformations. Nanocellulose surface modification techniques are typically used to introduce either charged or hydrophobic moieties, and include amidation, esterification, etherification, silylation, polymerization, urethanization, sulfonation, and phosphorylation. Nanocellulose has excellent strength, high Young's modulus, biocompatibility, and tunable self-assembly, thixotropic, and photonic properties, which are essential for the applications of this material. Nanocellulose participates in the fabrication of a large range of nanomaterials and nanocomposites, including those based on polymers, metals, metal oxides, and carbon. In particular, nanocellulose complements organic-based materials, where it imparts its mechanical properties to the composite. Nanocellulose is a promising material whenever material strength, flexibility, and/or specific nanostructuration are required. Applications include functional paper, optoelectronics, and antibacterial coatings, packaging, mechanically reinforced polymer composites, tissue scaffolds, drug delivery, biosensors, energy storage, catalysis, environmental remediation, and electrochemically controlled separation. Phosphorylated nanocellulose is a particularly interesting material, spanning a surprising set of applications in various dimensions including bone scaffolds, adsorbents, and flame retardants and as a support for the heterogenization of homogeneous catalysts.

Thermally Switchable Liquid Crystals Based on Cellulose Nanocrystals with Patchy Polymer Grafts

A thermally "switchable" liquid-crystalline (LC) phase is observed in aqueous suspensions of cellulose nanocrystals (CNCs) featuring patchy grafts of the thermoresponsive polymer poly(N-isopropylacrylamide) (PNIPAM). "Patchy" polymer decoration of the CNCs is achieved by preferential attachment of an atom transfer radical polymerization (ATRP) initiator to the ends of the rods and subsequent surface-initiated ATRP. The patchy PNIPAM-grafted CNCs display a higher colloidal stability above the lower critical solution temperature (LCST) of PNIPAM than CNCs decorated with PNIPAM in a brush-like manner. A 10 wt% suspension of the "patchy" PNIPAM-modified CNCs displays birefringence at room temperature, indicating the presence of an LC phase. When heated above the LCST of PNIPAM, the birefringence disappears, indicating the transition to an isotropic phase. This switching is reversible and appears to be driven by the collapse of the PNIPAM chains above the LCST, causing a reduction of the rods' packing density and an increase in translational and rotational freedom. Suspensions of the "brush" PNIPAM-modified CNCs display a different behavior. Heating above the LCST causes phase separation, likely because the chain collapse renders the particles more hydrophobic. The thermal switching observed for the "patchy" PNIPAM-modified CNCs is unprecedented and possibly useful for sensing and smart packaging applications.

Covalent Tethering of Temperature Responsive pNIPAm onto TEMPO-Oxidized Cellulose Nanofibrils via Three-Component Passerini Reaction

A critical challenge in the application of functional cellulose fibrils is to perform efficient surface modification without disrupting the original properties. Three-component Passerini reaction (Passerini 3-CR) is regarded as an effective functionalization approach which can be carried out under mild and fast reaction condition. In this study, we investigated the application of Passerini 3-CR for the synthesis of thermoresponsive cellulose fibrils by covalently tethering poly(N-isopropylacrylamide) in aqueous condition at ambient temperature. The three components, a TEMPO-oxidized cellulose nanofiber bearing carboxylic acid moieties (TOCN-COOH), a functionalized polymer with aldehyde group (pNIPAm-COH) and a cyclohexyl isocyanide, were reacted in one pot resulting in 36% of grafting efficiency within 30 min. The chemical coupling was evidenced by improved aqueous dispersibility, which was further confirmed by FT-IR, TGA, UV-vis, and turbidity study. It was observed that the grafting efficiency is strongly dependent on the chain length of the polymer. Furthermore, AFM and X-ray diffraction measurements affirmed the suitability of the proposed method for chemical modification of cellulose nanofibers without significantly compromising the original morphology and structural integrity.

Dually sensitive dextran-based micelles for methotrexate delivery

Temperature and pH-sensitive micelles prepared from dextran grafted with poly(N-isopropylacrylamide) (PNIPAAm)/polyethylene glycol methyl ether (PEGMA) with/without 2-aminoethylmethacrylate (2-AEM) were evaluated as methotrexate delivery systems.

The development of sustained release drug delivery platforms using melt-extruded cellulose-based polymer blends

OBJECTIVES

This research examined the application of hot melt extrusion (HME) in the preparation of matrix formulations containing hydroxypropyl cellulose (HPC) as a base polymer in combination with methyl cellulose (MC) and hydroxypropyl methylcellulose (HPMC).

METHODS

The limit to which formulations could control drug release under varying paddle speeds, high alcohol environments and high and low drug loads was investigated on a Caleva 10 ST dissolution tester. Rheological studies and hot plate imaging highlighted the impact of thermoresponsive polymers on drug release. The rate and percentage release of drug were analysed using a one-way ANOVA and Tukey's HSD test.

KEY FINDINGS

No significant differences in the amount of drug released were calculated as a result of paddle speed variation or in the presence of 40% v/v ETOH. The phase separation effects of temperature-sensitive polymers HPC and MC and the characteristic gel shrinkage and fluid expulsion were shown to be contributing factors. The use of the partition activity, α, identified the extent to which formulations were affected by phase separation.

CONCLUSION

Hot melt extrusion was successfully used to manufacture cellulose-based formulations. Thermoresponsive polymers HPC and MC significantly impacted drug release properties.

Stimuli-Responsive Cellulose Nanocrystals for Surfactant-Free Oil Harvesting

Cellulose nanocrystals with grafted binary polymer brushes (CNC-BPB), poly(oligoethylene glycol) methacrylate (POEGMA) and poly(methacrylic acid) (PMAA), were prepared by cerium-mediated polymerization in aqueous solution. The physical properties of CNC-BPB can be controlled by external triggers, such as temperature and pH, which can be utilized to stabilize and destabilize oil-water emulsions. By virtue of the modifications, these bifunctionalized CNCs diffused to the oil-water interface and stabilized the oil droplets at high pHs. When the pH was lowered to 2, strong hydrogen bonding between POEGMA and PMAA chains grafted on the CNC induced the coalescence of the emulsion droplets, resulting in the phase separation of oil and water. For emulsions stabilized by CNC-POEGMA and free PMAA mixtures, instantaneous coalescence was not observed at low pHs. Successive stabilization-destabilization over 5 cycles was demonstrated by modulating the pH with the addition of acid or base without any loss in efficiency. This work demonstrates that functional sustainable nanomaterials can be used for small scale oil-water separations, particularly for oil droplet transportation and harvesting of lipophilic compounds.

Tunable dynamic hydrophobic attachment of guest molecules in amphiphilic core–shell polymers

In this study, synthesis and dynamic properties of amphiphilic core–shell polymers are reported as monitored through their interaction with small amphiphilic ligands. Our findings point to a most complex self-assembling nature of those host and guest molecules.

Intracellular delivery cellulose-based bionanogels with dual temperature/pH-response for cancer therapy

Polysaccharide-based crosslinked nanogles (bionanogels) exhibiting multiple stimuli-responsive release of encapsulated therapeutics hold a great potential as tumor-targeting intracelluar durg delivery nanocarriers. Herein, we report the synthesis of monodisperse dual temperature/acidic pH-responsive bionanogels (DuR-BNGs) by aqueous crosslinking polymerization through temperature-induced self-association method. The DuR-BNGs have prolonged colloidal stability and negligible non-specific interactions with proteins. In response to acidic pH at higher temperature (above lower critical solution temperature), they exhibit synergistic release of anticancer drugs as a consequence of both acidic pH-sensitivity of carboxymethyl cellulose and temperature-induced volume change of grafted thermoresponsive copolymers. In vitro cell culture results suggest that new colloidally-stable DuR-BNG is a promising candidate promoting dual stimuli-responsive drug release for cancer therapy.

Synthesis and click chemistry of a new class of biodegradable polylactide towards tunable thermo-responsive biomaterials

A new class of clickable and biodegradable polylactide was designed and prepared via bulk polymerization of 3,6-dipropargyloxymethyl-1,4-dioxane-2,5-dione (1) which was synthesized from easily accessible propargyloxylactic acid (5). A homopolymer of 1 and random copolymer of 1 with l-lactide were obtained as amorphous materials and exhibit low Tg of 8.5 and 34 °C, respectively, indicating their promising potentials for biomedical applications. The statistical nature of random copolymers was investigated by DSC analysis and 13C NMR spectroscopy, which implies the random distribution of terminal alkyne groups along the back bone of copolymers. The efficient click post-modification of this new class of polylactide with alkyl and mPEG azides affords novel hydrophilic biomaterials, which exhibit reversible thermo-responsive properties as evidenced by their tunable LCST ranging from 22 to 69 °C depending on the balance of the incorporated hydrophilic/hydrophobic side chains. These results indicate the generality of this new class of clickable polylactide in preparing novel smart biomaterials in a simple and efficient manner via click chemistry.

Chitosan oligosaccharide copolymer micelles with double disulphide linkage in the backbone associated by H-bonding duplexes for targeted intracellular drug delivery

Folic acid conjugated block copolymer micelles with H-bonding associated double disulphide linkage in the backbone were developed.