Enhanced photodynamic antimicrobial activity of surface modified SiNPs doped with zinc(II) phthalocyanines: The effect of antimicrobial ampicillin and extra charges from a sultone

1-(2-Methoxyethyl)piperidine sustituted Zn phthalocyanine complex (2) is synthesised and quartenised (3). These complexes are loaded into silica nanoparticles (SiNPs) that are futher surface modified with ampicillin and 1.3-propanesultone. The photophysical and photochemical properties of the complexes and their doped conjugates were investigated in dimethylsulfoxide. The cationic complex (3) is used for photodynamic antimicrobial activity. Log reduction values of above 9 are obtained towards the photoiactivation of Staphyloccocus aureus.

Bicomponent Carbon Fibre within Woven Fabric for Protective Clothing

For the purpose of this research, six types of woven fabrics with different proportions of bicomponent carbon fibres (CF), differently distributed in the fabric, were woven and tested. Fibre composition in the core and sheath was determined with X-ray spectroscopy (EDS). Two types of bicomponent CF were selected which are characterised by different proportions of carbon and other polymers in the fibre core and sheath and different cross-sections of the fibres formed during chemical spinning. Physical-mechanical properties were investigated, as well as deformations of fabrics after 10,000, 20,000 and 30,000 cycles under biaxial cyclic stress on a patented device. Tests of the surface and vertical electrostatic resistance from fabric front to back side and from the back side to the fabric front were conducted. According to the obtained results and statistical analyses, it was concluded that the proportion of CF affects the fabric’s physical and mechanical properties, the electrostatic resistance as well as the deformations caused by biaxial cyclic stresses. A higher proportion of CF in the fabric and a higher proportion of carbon on the fibre surface, gave lower electrostatic resistance, i.e., better conductivity, especially when CFs are woven in the warp and weft direction. The higher presence of CF on the front of the fabric, as a consequence of the weave, resulted in a lower surface electrostatic resistance.

Cellulose-Based Hydrogels as Sustained Drug-Delivery Systems

Hydrogels, three-dimensional (3D) polymer networks, present unique properties, like biocompatibility, biodegradability, tunable mechanical properties, sensitivity to various stimuli, the capacity to encapsulate different therapeutic agents, and the ability of controlled release of the drugs. All these characteristics make hydrogels important candidates for diverse biomedical applications, one of them being drug delivery. The recent achievements of hydrogels as safe transport systems, with desired therapeutic effects and with minimum side effects, brought outstanding improvements in this area. Moreover, results from the utilization of hydrogels as target therapy strategies obtained in clinical trials are very encouraging for future applications. In this regard, the review summarizes the general concepts related to the types of hydrogel delivery systems, their properties, the main release mechanisms, and the administration pathways at different levels (oral, dermal, ocular, nasal, gastrointestinal tract, vaginal, and cancer therapy). After a general presentation, the review is focused on recent advances in the design, preparation and applications of innovative cellulose-based hydrogels in controlled drug delivery.

Nacre-Inspired Polymeric Materials with Body Heat-Responsive Shape-Memory Effect, High Optical Transparence, and Balanced Mechanical Properties

In this work, inspired by the hierarchical architecture of nacre, we have fabricated poly(propylene carbonate) (PPC)/thermoplastic polyurethane (TPU) alternating multilayer films via layer-multiplying coextrusion. Based on the glass transition at around 37 °C of PPC, the multilayer films exhibited an outstanding body heat-responsive shape-memory effect (SME) with high shape fixation and recovery ratios (96.1 and 93.6%), much better than the conventional cocontinuous blend with the same compositions. It was revealed that the high phase continuity and abundantly two-dimensional interfaces both capable of promoting stress transferring and load distribution maximally contributed to the SME. Furthermore, the multilayer films showed a superior recovery stress storage capacity and the force generated by shape recovery allowed automatic expansion of the spiral in 37 °C water and efficient lifting of a load 880 times its weight. Different from the opacity of the blend, a high optical transparence was observed in the multilayers because of the parallel assembly of transparent PPC and TPU enabling light to directly pass through the films. Besides, the nacre-like films had layer debonding and layer stepwise breaking during stretching, resulting in a 90% increase in tensile strength, a 70% increase in elongation at break, and onefold improvement in yield stress, compared with those of the blend. Our approach paves a new way for developing bioinspired structural materials with excellent optical, mechanical, and shape-memory properties, which can be extended to different amorphous polymers and elastomers. Also, the materials presented herein have great potential in applications of biomedical devices and soft robotics.

Exploiting Nonlinear Elasticity for Anomalous Magnetoresponsive Stiffening

A paradigm for enhanced magnetorheological elastic materials is introduced and experimentally established. We show that a nonlinearly stiffening polymer matrix can be exploited to achieve anomalous magneto-elastomer stiffening exceeding standard magneto-elastomer theory and experiment in terms of percentage stiffness change and sensitivity to applied magnetic flux. Using a model system of a semiflexible fibrin network embedded with micron sized carbonyl iron particles, we demonstrate that even at a modest particle volume fraction (0.5-4%), a coupling between the magnetically interacting dipoles and a strain-stiffening polymer mesh provides previously unexplored opportunities for material design. Our experiments indicate that confined particles within the fibrin network internally tension and stiffen the polymer mesh when an external field is applied, resulting in a field-dependent stiffening response from the polymer mesh that superposes with the magnetic interparticle interactions.

Conducting chitosan/hydroxylethyl cellulose/polyaniline bionanocomposites hydrogel based on graphene oxide doped with Ag-NPs

The current work focuses on a cheap and simple preparation of highly conducting chitosan/hydroxyl ethylcellulose/polyaniline loaded with graphene oxide doped by silver nanoparticles (CS/HEC/PAni/GO@Ag) bionanocomposite as a biodegradable and biocompatible hydrogel for energy storage technology. Scanning electron microscopy (SEM) displays the compatibility of chitosan, hydroxyl ethyl cellulose, and polyaniline and a good distribution of GO@Ag-NPs in bionanocomposite hydrogels. X-ray diffraction (XRD) displayed the structure and existence of GO@Ag-NPs in the matrix. The swelling percentage and the antibacterial activities slightly increased with raising the content of GO@Ag-NPs. Also, the presence of both chitosan and cellulose improves the biodegradation of the fabricated bionanocomposites, which is increased by adding GO. Moreover, the incorporation of 5% GO@Ag-NPs in hydrogels enhances dc-conductivity by about 25 times from 3.37 × 10^-3 to 8.53 × 10^-2 S/cm. The fabricated hydrogels are inexpensive, eco-friendly, and have high capacitance and permittivity, and so they can store electrical energy.

Transferred Photothermal to Photodynamic Therapy Based on the Marriage of Ultrathin Titanium Carbide and Up-Conversion Nanoparticles

In this research, upconversion nanoparticles (UCNPs) are used as a light conversion carrier, and their deep light source penetrability is closely combined with ultrathin two-dimensional (2D) Ti₃C₂T_x to explore the application efficiency of the complex in phototherapy. Due to the advantages of 2D Ti₃C₂T_x with its high absorbance to ultraviolet/visible light, rich atomic defects to load the drugs, and adjustable thinner structure, this 2D material is beneficially applied as the energy donor. UCNPs@Ti₃C₂T_x with a photothermal conversion efficiency of 20.7% is proven with the ability to generate reactive oxygen species under a 980 nm laser at the cellular level. Importantly, the main photothermal therapy method can be changed to a photodynamic therapy method due to the degradation of Ti₃C₂T_x to TiO₂ under the oxygen-bearing environment. The in vivo experiment was continued to verify that UCNPs@Ti₃C₂T_x can kill tumor cells and inhibit tumor growth within a certain period. In addition, in vivo treatment with a combination of immunotherapy and phototherapy of UCNPs@ Ti₃C₂T_x is carried out to achieve stronger tumor inhibition over the prolonged time points.

Multi-Responsive Silk Fibroin-Based Nanoparticles for Drug Delivery

Silk fibroin has the merits of biocompatibility, biodegradability, ease of processing, and feasibility of modification, which present it as a promising drug delivery material. This review focuses on the structures of silk fibroin, the controlled transformation of secondary structures, and the formation mechanism of silk fibroin-based nanoparticles (SFNPs). We also discuss the intrinsic multi-responsive, surface functionalization, and transgenic modification of SFNPs for drug delivery.

Hyperthermia evaluation and drug/protein-controlled release using alternating magnetic field stimuli-responsive Mn-Zn ferrite composite particles

Drug delivery particles in which the release of biomolecules is triggered by a magnetic simulant have attracted much attention and may have great potential in the fields of cancer therapy and tissue regenerative medicine. In this study, we have prepared magnetic Mn–Zn ferrite ((Mn,Zn)Fe₂O₄) (MZF) nanoparticles coated with chitosan-g-N-isopropylacrylamide (Chi-g-NIPAAm) polymer (MZF@Chi-g-NIPAAm) to deliver the anticancer drug (Doxorubicin, DOX) and bioactive proteins (Bone morphogenic protein (BMP-2)-immobilized bovine serum albumin (BSA)) (P//MZF@Chi-g-NIPAAm) and be used as chemo-hyperthermia and vector delivering biomolecules. For these purposes, we first show that the as-prepared MZF@Chi-g-NIPAAm particles exhibit super paramagnetic behavior and under certain conditions, they can act as a heat source with a specific absorption rate (SAR) of 34.88 W g⁻¹. Under acidic conditions and in the presence of AMF, the fast release of DOX was seen at around 58.9% within 20 min. In vitro evaluations indicated that concurrent thermo-chemotherapy treatment by DOX-MZF@Chi-g-NIPAAm using AMF had a better antitumor effect, compared with those using either DOX or DOX-MZF@Chi-g-NIPAAm without AMF (89.02% of cells were killed as compared to 71.82% without AMF exposure). Up to 28.18% of the BSA (used as the model protein to determine the controlled release) is released from the P//MZF@Chi-g-NIPAAm particles under AMF exposure for 1 h (only 17.31% was released without AMF). These results indicated that MZF@Chi-g-NIPAAm particles could be used to achieve hyperthermia at a precise location, effectively enhancing the chemotherapy treatments, and have a promising future as drug or bioactive delivering molecules for cancer treatment and cartilage or bone regenerative applications.

Drug delivery particles in which the release of biomolecules is triggered by a magnetic simulant have attracted much attention and may have great potential in the fields of cancer therapy and tissue regenerative medicine.

Detonation nanodiamonds-phthalocyanine photosensitizers with enhanced photophysicochemical properties and effective photoantibacterial activity

The nanophotosensitizers based on acetophenoxy tetrasubstituted metallophthalocyanines (MPc) and detonation nanodiamonds (DNDs) were successfully formed and their photophysicochemical properties were determined. The zinc(II)Pc and indium(III)Pc complexes along with their nanoconjugates were found to have high singlet oxygen quantum yields (0.72 - 0.84) associated with the heavy central metal effect. The ability of the functional groups present on the DNDs to bind to the bacteria cell and the improved solubility of the nanoconjugates due to DNDs resulted in effective photodynamic antimicrobial therapy (PACT) activity against S. aureus planktonic cells, with the highest log reduction of 9.72 ± 0.02 for the conjugate of InPc conjugate with DNDs after 30 min irradiation. PACT studies were investigated at a dose of 10 μg/mL for each sample. The results suggest that the readily synthesized nanoconjugates can be used as appropriate PACT agents.

Fabrication of tri-layered electrospun polycaprolactone mats with improved sustained drug release profile

Modulation of initial burst and long term release from electrospun fibrous mats can be achieved by sandwiching the drug loaded mats between hydrophobic layers of fibrous polycaprolactone (PCL). Ibuprofen (IBU) loaded PCL fibrous mats (12% PCL-IBU) were sandwiched between fibrous polycaprolactone layers during the process of electrospinning, by varying the polymer concentrations (10% (w/v), 12% (w/v)) and volume of coat (1 ml, 2 ml) in flanking layers. Consequently, 12% PCL-IBU (without sandwich layer) showed burst release of 66.43% on day 1 and cumulative release (%) of 86.08% at the end of 62 days. Whereas, sandwich groups, especially 12% PCLSW-1 & 2 (sandwich layers-1 ml and 2 ml of 12% PCL) showed controlled initial burst and cumulative (%) release compared to 12% PCL-IBU. Moreover, crystallinity (%) and hydrophobicity of the sandwich models imparted control on ibuprofen release from fibrous mats. Further, assay for cytotoxicity and scanning electron microscopic images of cell seeded mats after 5 days showed the mats were not cytotoxic. Nuclear Magnetic Resonance spectroscopic analysis revealed weak interaction between ibuprofen and PCL in nanofibers which favors the release of ibuprofen. These data imply that concentration and volume of coat in flanking layer imparts tighter control on initial burst and long term release of ibuprofen.

Effect of conducting/thermoresponsive polymer ratio on multitasking nanogels

Semi-interpenetrated nanogels (NGs) able to release and sense diclofenac (DIC) have been designed to act as photothermal agents with the possibility to ablate cancer cells using mild-temperatures (<45 °C). Combining mild heat treatments with simultaneous chemotherapy appears as a very promising therapeutic strategy to avoid heat resistance or damaging the surrounding tissues. Particularly, NGs consisted on a poly(N-isopropylacrylamide) (PNIPAM) and dendritic polyglycerol (dPG) mesh containing a semi-interpenetrating network (SIPN) of poly(hydroxymethyl 3,4-ethylenedioxythiophene) (PHMeEDOT). The PHMeEDOT acted as photothermal and conducting agent, while PNIPAM-dPG NG provided thermoresponsivity and acted as stabilizer. We studied how semi-interpenetration modified the physicochemical characteristics of the thermoresponsive SIPN NGs and selected the best condition to generate a multifunctional photothermal agent. The thermoswitchable conductiveness of the multifunctional NGs and the redox activity of DIC could be utilized for its electrochemical detection. Besides, as proof of the therapeutic concept, we investigated the combinatorial effect of photothermal therapy (PTT) and DIC treatment using the HeLa cancer cell line in vitro. Within 15 min NIR irradiation without surpassing 45 °C we were able to kill 95% of the cells, demonstrating the potential of SIPN NGs as drug carriers, sensors and agents for mild PTT.

Emerging Roles of 1D Vertical Nanostructures in Orchestrating Immune Cell Functions

Engineered nano-bio cellular interfaces driven by 1D vertical nanostructures (1D-VNS) are set to prompt radical progress in modulating cellular processes at the nanoscale. Here, tuneable cell-VNS interfacial interactions are probed and assessed, highlighting the use of 1D-VNS in immunomodulation, and intracellular delivery into immune cells-both crucial in fundamental and translational biomedical research. With programmable topography and adaptable surface functionalization, 1D-VNS provide unique biophysical and biochemical cues to orchestrate innate and adaptive immunity, both ex vivo and in vivo. The intimate nanoscale cell-VNS interface leads to membrane penetration and cellular deformation, facilitating efficient intracellular delivery of diverse bioactive cargoes into hard-to-transfect immune cells. The unsettled interfacial mechanisms reported to be involved in VNS-mediated intracellular delivery are discussed. By identifying up-to-date progress and fundamental challenges of current 1D-VNS technology in immune-cell manipulation, it is hoped that this report gives timely insights for further advances in developing 1D-VNS as a safe, universal, and highly scalable platform for cell engineering and enrichment in advanced cancer immunotherapy such as chimeric antigen receptor-T therapy.

SYNTHESIS, CHARACTERIZATION AND IN VIVO EVALUATION OF PH SENSITIVE HYDROXYPROPYL METHYL CELLULOSE-GRAFT-ACRYLIC ACID HYDROGELS FOR SUSTAINED DRUG RELEASE OF MODEL DRUG NICORANDIL

Background: Anti hypertensive drugs like “Nicorandil” require frequent dosing due to their shorter half-life. Such drugs are also pH sensitive, due to which greater portions of these drugs are degraded in acidic pH of stomach resulting in lesser bioavailability. The objective of this study was to formulate graft polymeric carrier system for sustained delivery of nicorandil to minimize dosing frequency and enhance patient compliance. Materials Methods: This animal model study was conducted in Department of Pharmacy, Islamia University of Bahawalpur, Pakistan. Hydroxypropyl methyl cellulose-graft-acrylic acid hydrogels were synthesized by free radical solution polymerization with diverse weight ratios of polymer, monomer and cross linker. Total duration of study was 1.5 years from March 2013 to August 2015. The N, N-methylene bis acrylamide and potassium persulfate were used as crosslinker and initiator respectively. Hydrogels were characterized for swelling ratio, equilibrium swelling, gel content, porosity and in vitro drug release. The surface morphology of synthesized hydrogels was evaluated by using Scanning Electron Microscopy. Thermal properties of hydrogels were evaluated by Thermogravimetric Analysis and Differential Scanning Calorimetry whereas FTIR was done to examine chemical compatibility. Finally, in vivo evaluation of prepared hydrogels was carried out in rabbits using simple parallel study design to estimate various pharmacokinetic parameters.Results: HPMC-co-AA hydrogels had good pH sensitivity whereas; they demonstrated maximum and minimum swelling at pH 7.4 and 1.2 respectively. Swelling ratio, gel fraction and cumulative percent drug release were decreased with increasing crosslinker concentration while these parameters were increased with increasing AA and HPMC concentrations. A porous network was observed in the SEM images. All formulation ingredients of prepared hydrogels showed good compatibility as determined by FTIR. Results of in vivo study proved the pH sensitivity and sustained drug release of prepared hydrogels.Conclusion: The HPMC-graft-AA hydrogels showed good pH-sensitivity and sustained-release profile for model drug nicorandil.

Multiple applications of polymers containing electron-reservoir metal-sandwich complexes

Ferrocene-containing polymers have been investigated for more than six decades, and more recently modern synthetic methods have allowed the fabrication of precise polymers that contain a variety of transition-metal complexes. Trends are now oriented towards applications, such as optics, energy conversion and storage, electrochemistry, magnetics, electric conductors and biomedicine. Metal-sandwich complexes such as those of ferrocene type and other related complexes that present redox-robust groups in polymers, i.e. that are isolable in both their oxidized and reduced forms, are of particular interest, because it is possible to address them using electronic or photonic redox stimuli for application. Our research groups have called such complexes Electron-Reservoirs and introduced them in the main chain or in the side chains of well-defined polymers. For instance, polymers with ferrocene in the main chain or in the side chain are oxidized to stable polycationic polyelectrolytes only if ferrocene is part of a biferrocene unit, because biferrocene oxidation leads to the biferrocenium cation that is stabilized by the mixed valency. Then a group of several redox-robust iron sandwich complexes were fabricated and incorporated in precise polymers including multi-block copolymers whose controlled synthesis and block incorporation was achieved for instance using ring-opening-metathesis polymerization. Applications of this family of Electron-Reservoir-containing polymers includes electrochemically induced derivatization of electrodes by decorating them with these polymers, molecular recognition and redox sensing, electrochromics with multiple colours, generation of gold and silver nanoparticles of various size by reduction of gold(iii) and silver(i) precursors and their use for nanocatalysis towards depollution and biomedicine.

Shear Speed-Regulated Properties of Long-Acting Docetaxel Control Release Poly (Lactic-Co-Glycolic Acid) Microspheres

Advanced drug carriers for the controlled release of chemotherapeutics in the treatment of malignant tumors have drawn significant notice in recent years. In the current study, microspheres (MPs) loaded with docetaxel (DTX) were prepared using polylactic-co-glycolic acid copolymer (PLGA). The double emulsion solvent evaporation method is simple to perform, and results in high encapsulation efficiency. Electron micrographs of the MPs showed that controlling the shear rate can effectively control the size of the MPs. At present, most DTX sustained-release carriers cannot maintain stable and long-term local drug release. The 1.68 μm DTX-loaded microspheres (MP/DTX) with elastase was completely degraded in 14 d. This controlled degradation period is similar to a course of treatment for most cancers. The drug release profile of all kinds of MP/DTX demonstrated an initial rapid release, then slower and stable release to the end. The current study demonstrates that it is possible to create drug-loaded MPs with specific degradation times and drug release curves, which may be useful in achieving optimal treatment times and drug release rates for different diseases, and different drug delivery routes. The initial burst release reaches the effective concentration of the drug at the beginning of release, and then the drug concentration is maintained by stable release to reduce the number of injections and improve patient compliance.

Bio-Based Electrospun Fibers for Wound Healing

Being designated to protect other tissues, skin is the first and largest human body organ to be injured and for this reason, it is accredited with a high capacity for self-repairing. However, in the case of profound lesions or large surface loss, the natural wound healing process may be ineffective or insufficient, leading to detrimental and painful conditions that require repair adjuvants and tissue substitutes. In addition to the conventional wound care options, biodegradable polymers, both synthetic and biologic origin, are gaining increased importance for their high biocompatibility, biodegradation, and bioactive properties, such as antimicrobial, immunomodulatory, cell proliferative, and angiogenic. To create a microenvironment suitable for the healing process, a key property is the ability of a polymer to be spun into submicrometric fibers (e.g., via electrospinning), since they mimic the fibrous extracellular matrix and can support neo- tissue growth. A number of biodegradable polymers used in the biomedical sector comply with the definition of bio-based polymers (known also as biopolymers), which are recently being used in other industrial sectors for reducing the material and energy impact on the environment, as they are derived from renewable biological resources. In this review, after a description of the fundamental concepts of wound healing, with emphasis on advanced wound dressings, the recent developments of bio-based natural and synthetic electrospun structures for efficient wound healing applications are highlighted and discussed. This review aims to improve awareness on the use of bio-based polymers in medical devices.

A biocompatible glycol-capped nano-delivery system with stimuli-responsive drug release kinetics abrogates cancer cell survival

An eco-friendly polysaccharide (PSP001) isolated from the fruit rind of Punica granatum is a biodegradable polymer with immunostimulatory and anticancer properties. PSP001 was employed for the stimuli-responsive targeted delivery of antineoplastic agent doxorubicin (Dox) by the fabrication of Dox-holding PSP nanoparticles (DPN). The galactose moieties of PSP001 were occupied as an effective tumor-targeted motif against the over-expressed asialoglycoprotein and galectin receptors of cancers. DPN followed a pH-sensitive cargo release kinetics, competent cancer cell internalization profile, and appealing biocompatibility towards peripheral red blood cells. The selective execution of caspase-mediated programmed cell death by the DPN on cancer cells was confirmed with multiple apoptosis studies. Extensive toxicity profiling on BALB/c mice rules out any palpable signs of abnormality with DPN administration while bare Dox produced vital signs of toxicity. Studies on syngraft solid tumor-bearing mice uncovered the tumor homing nature of DPN with the subsequent release of the entrapped drug which further translated in the direction of a significant reduction in the tumor payload and enhanced survival benefits, thus offering a robust approach towards endurable cancer management.

A Molecular-Level Picture of Electrospinning

Electrospinning is a modern and versatile method of producing nanofibers from polymer solutions or melts by the action of strong electric fields. The complex, multiscale nature of the process hinders its theoretical understanding, especially at the molecular level. The present article aims to contribute to the fundamental picture of the process by the molecular modeling of its nanoscale analogue and complements the picture by laboratory experiments at macroscale. Special attention is given to how the process is influenced by ions. Molecular dynamics (MD) is employed to model the time evolution of a nanodroplet of aqueous poly(ethylene glycol) (PEG) solution on a solid surface in a strong electric field. Two molecular weights of PEG are used, each in 12 aqueous solutions differing by the weight fraction of the polymer and the concentration of added NaCl. Various structural and dynamic quantities are monitored in production trajectories to characterize important features of the process and the effect of ions on it. Complementary experiments are carried out with macroscopic droplets of compositions similar to those used in MD. The behavior of droplets in a strong electric field is monitored using an oscilloscopic method and high-speed camera recording. Oscilloscopic records of voltage and current are used to determine the characteristic onset times of the instability of the meniscus as the times of the first discharge. The results of simulations indicate that, at the molecular level, the process is primarily driven by polarization forces and the role of ionic charge is only minor. Ions enhance the evaporation of solvent and the transport of polymer into the jet. Experimentally measured instability onset times weakly decrease with increasing ionic concentration in solutions with low polymer content. High-speed photography coupled with oscilloscopic measurement shows that the measured instability onset corresponds to the formation of a sharp tip of the Taylor cone. Molecular-scale and macroscopic views of the process are confronted, and challenges for their reconciliation are presented as a route to a true understanding of electrospinning.

Recent Achievements in Polymer Bio-Based Flocculants for Water Treatment

Polymer flocculants are used to promote solid-liquid separation processes in potable water and wastewater treatment. Recently, bio-based flocculants have received a lot of attention due to their superior advantages over conventional synthetic polymers or inorganic agents. Among natural polymers, polysaccharides show many benefits such as biodegradability, non-toxicity, ability to undergo different chemical modifications, and wide accessibility from renewable sources. The following article provides an overview of bio-based flocculants and their potential application in water treatment, which may be an indication to look for safer alternatives compared to synthetic polymers. Based on the recent literature, a new approach in searching for biopolymer flocculants sources, flocculation mechanisms, test methods, and factors affecting this process are presented. Particular attention is paid to flocculants based on starch, cellulose, chitosan, and their derivatives because they are low-cost and ecological materials, accepted in industrial practice. New trends in water treatment technology, including biosynthetic polymers, nanobioflocculants, and stimulant-responsive flocculants are also considered.

Developing a colorimetric nucleic acid-responsive DNA hydrogel using DNA proximity circuit and catalytic hairpin assembly

The development of powerful techniques for sensitive detection of nucleic acids has attracted much attention for fabricating accurate biosensors in various fields, such as genomics, clinical diagnostics, and forensic sciences. Up to now, different systems have been introduced, the majority of which are expensive, time-consuming, and relatively low selectivity/limit of detection. These limitations caught our attention to fabricate a nucleic acid responsive system by combining three layers of signal amplification strategy, namely a split proximity circuit (SPC), a catalytic hairpin assembly (CHA), and a DNA hydrogel. Herein, by SPC operation, two initiators and a target strand were assembled and activated the CHA reaction in the presence of three 5'-cytosine (C)-rich hairpins. Then, produced C-rich embedded three-way junction structures could form i-motif structures under acidic environment followed by a transition from sol to gel state. To acquire a quantitative and colorimetric measurement, gold nanoparticles (GNPs) were used that encapsulated and sediment by the gel formation. The resulting platform detected the target with a limit of detection of 1 pM and considerable selectivity.

Interfacial nanoarchitectonics for responsive cellular biosystems

The living cell can be regarded as an ideal functional material system in which many functional systems are working together with high efficiency and specificity mostly under mild ambient conditions. Fabrication of living cell-like functional materials is regarded as one of the final goals of the nanoarchitectonics approach. In this short review article, material-based approaches for regulation of living cell behaviors by external stimuli are discussed. Nanoarchitectonics strategies on cell regulation by various external inputs are first exemplified. Recent approaches on cell regulation with interfacial nanoarchitectonics are also discussed in two extreme cases using a very hard interface with nanoarchitected carbon arrays and a fluidic interface of the liquid-liquid interface. Importance of interfacial nanoarchitectonics in controlling living cells by mechanical and supramolecular stimuli from the interfaces is demonstrated.

Electrospun freestanding hydrophobic fabric as a potential polymer semi-permeable membrane for islet encapsulation

One of the significant problems associated with islet encapsulation for type 1 diabetes treatment is the loss of islet functionality or cell death after transplantation because of the unfavorable environment for the cells. In this work, we propose a simple strategy to fabricate electrospun membranes that will provide a favorable environment for proper islet function and also a desirable pore size to cease cellular infiltration, protecting the encapsulated islet from immune cells. By electrospinning the wettability of three different biocompatible polymers: cellulose acetate (CA), polyethersulfone (PES), and polytetrafluoroethylene (PTFE) was greatly modified. The contact angle of electrospun CA, PES, and PTFE increased to 136°, 126°, and 155° as compared to 55°, 71°, and 128° respectively as a thin film, making the electrospun membranes hydrophobic. Commercial porous membranes of PES and PTFE show a contact angle of 30° and 118°, respectively, confirming the hydrophobicity of electrospun membranes is due to the surface morphology induced by electrospinning. In- vivo results confirm that the induced hydrophobicity and surface morphology of electrospun membranes impede cell attachment, which would help in maintaining the 3D circular morphology of islet cell. More importantly, the pore size of 0.3-0.6 μm obtained due to the densely packed structure of nanofibers, will be able to restrict immune cells but would allow free movement of molecules like insulin and glucose. Therefore, electrospun polymer fibrous membranes as fabricated in this work, with hydrophobic and porous properties, make a strong case for successful islet encapsulation.

Oxime-based 19-nortestosterone-pheophorbide a conjugate: bimodal controlled release concept for PDT

Photodynamic therapy has become a feasible direction for the treatment of both malignant and non-malignant diseases. It has been in the spotlight since FDA regulatory approval was granted to several photosensitizers worldwide. Nevertheless, there are still strong limitations in the targeting specificity that is vital to prevent systemic toxicity. Here, we report the synthesis and biological evaluation of a novel bimodal oxime conjugate composed of a photosensitizing drug, red-emitting pheophorbide a, and nandrolone (NT), a steroid specifically binding the androgen receptor (AR) commonly overexpressed in various tumors. We characterized the physico-chemical properties of the NT-pheophorbide a conjugate (NT-Pba) and singlet oxygen generation. Because light-triggered therapies have the potential to provide important advances in the treatment of hormone-sensitive cancer, the biological potential of this novel specifically-targeted photosensitizer was assessed in prostatic cancer cell lines in vitro using an AR-positive (LNCaP) and an AR-negative/positive cell line (PC-3). U-2 OS cells, both with and without stable AR expression, were used as a second cell line model. Interestingly, we found that the NT-Pba conjugate was not only photodynamically active and AR-specific, but also that its phototoxic effect was more pronounced compared to pristine pheophorbide a. We also examined the intracellular localization of NT-Pba. Live-cell fluorescence microscopy provided clear evidence that the NT-Pba conjugate localized in the endoplasmic reticulum and mitochondria. Moreover, we performed a competitive localization study with the excess of nonfluorescent NT, which was able to displace fluorescent NT-Pba from the cell interior, thereby further confirming the binding specificity. The oxime ether bond degradation was assayed in living cells by both real-time microscopy and a steroid receptor reporter assay using AR U-2 OS cells. Thus, NT-Pba is a promising candidate for both the selective targeting and eradication of AR-positive malignant cells by photodynamic therapy.

A novel targeted delivery system for drug-resistant hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC) is a severe malignant disease threatening human life. Current chemotherapy methods usually result in poor prognosis with low treatment efficacy and high side effects because of weak targeting specificity and fast acquisition of multidrug resistance (MDR). HCSP4 is a 12-aa peptide previously identified to specifically and sensitively bind to HCC cells and tissues. In this study, a novel class of HCC-targeting doxorubicin (DOX) delivery system, named HCSP4-Lipo-DOX-miR101, was synthesized and investigated for anticancer activity. HCSP4-Lipo-DOX-miR101 exhibited specific HCC targeting characteristics and satisfactory anticancer potency against HepG2 and HepG2/ADR cells, particularly HepG2/ADR cells. Moreover, the expression levels of genes closely related to membrane transport and cancer growth were significantly suppressed. This finding suggests that HCSP4-Lipo-DOX-miR101 can cause DOX-resistant HCC cell death and growth inhibition based on the targeting of MDR-related genes by miR-101. In conclusion, the findings of this study suggest that HCSP4-Lipo-DOX-miR101 may serve as a promising novel targeted delivery system for improving the therapeutic efficiency of drug-resistant hepatocellular carcinoma.

Thermosensitive Chitosan-Based Injectable Hydrogel as an Efficient Anticancer Drug Carrier

A thermosensitive, physically cross-linked injectable hydrogel was formulated for the effective and sustained delivery of disulfiram (DSF) to the cancer cells as there is no hydrogel formulation available until now for the delivery of DSF. As we know, hydrogels have an advantage over other drug delivery systems because of their unique properties, so we proposed to formulate an injectable hydrogel system for the sustained delivery of an anticancer drug (DSF) to cancer cells. To investigate the surface morphology, a scanning electron microscope study was carried out, and for thermal stability of hydrogels, TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry) were performed. The rheological behavior of hydrogels was evaluated with the increasing temperature and time. These developed hydrogels possessing excellent biocompatibility could be injected at room temperature following rapid gel formation at body temperature. The swelling index and in vitro drug release studies were performed at different pH (6.8 and 7.4) and temperatures (25 and 37 °C). The cell viability of the blank hydrogel, free DSF solution, and Ch/DSF (chitosan/DSF)-loaded hydrogel was studied by MTT assay on SMMC-7721 cells for 24 and 48 h, which exhibited higher cytotoxicity in a dose-dependent manner in contrast to the free DSF solution. Moreover, the cellular uptake of DSF-loaded hydrogels was observed stronger as compared with free DSF. Hence, chitosan-based hydrogels loaded with DSF possessing exceptional properties can be used as a novel injectable anticancer drug for the sustained delivery of DSF for long-term cancer therapy.

Photo-induced specific intracellular release EGFR inhibitor from enzyme/ROS-dual sensitive nano-platforms for molecular targeted-photodynamic combinational therapy of non-small cell lung cancer

Molecular targeted-photodynamic combinational therapy is a promising strategy to enhance antitumor effects; meanwhile, current nanocarriers face challenges of limited selective delivery and release of therapeutic agents to specific tumor sites, which significantly compromises their therapeutic efficacy. Herein, we report active-targeting, enzyme- and ROS-dual responsive nanoparticles (HPGBCA) consisting of CD₄₄-targeting hyaluronic acid (HA) shells and afatinib (AFT)-loaded, ROS-sensitive poly(l-lysine)-conjugated chlorin e6 (Ce6) derivative nanoparticle cores (PGBCA). HPGBCA can actively carry AFT and Ce6 specifically to tumor cells due to the negatively charged HA and CD₄₄-mediated active targeting. Subsequently, hyaluronidase in the endosome will further spur the degradation of the HA shell to prompt exposure of the positively charged PGBCA core for rapid endosomal escape and intracellular delivery of AFT and Ce6. Furthermore, the generation of ROS produced by Ce6 under NIR irradiation can trigger the rapid oxidation of the thioether linker to facilitate the release of AFT into the cytoplasm. In vitro and in vivo studies demonstrated that the released AFT and excessive ROS at the local site can synergistically induce cell apoptosis to enhance the therapeutic efficacy without side effects. Our developed intelligent nanoparticle provides new avenues to achieve on-demand, specific intracellular drug release for improved molecular targeted-photodynamic combination therapeutic efficacy.

A fluorous biphase drug delivery system triggered by low frequency ultrasound: controlled release from perfluorous discoidal porous silicon particles

Conventional drug delivery systems face unsatisfactory loading efficiency, poor biological bypass, and uncontrollable release, which are great barriers for improving the treatment of many diseases. Herein, a proof-of-concept of a fluorous biphase drug delivery system (FB-DDS) trigged by low frequency ultrasound (LFUS) is proposed for the first time, where promoted incorporation and stabilization of therapeutic agents in nanocarriers was achieved through fluorine-fluorine interactions, and the encapsulated drugs were controllably released by external sources, resulting in minimized nonspecific toxicity and enhanced therapeutic efficacy. The FB-DDS was constructed from monodisperse, discoidal porous silicon particles (PSP) and was functionalized with 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS17) for loading perfluoropentane (PFP) and fluorinated drugs through fluorine-fluorine interactions. This delivery system was demonstrated by utilizing model compounds including a fluorous-tagged fluorescein and a fluorine containing antibiotic ciprofloxacin. Loading of the model molecules into fluorocarbon-coated carriers was facilitated by fluorous interactions, whereas ejection of the model molecules was promoted by applying LFUS to rapidly evaporate PFP. In the in vitro test, these carriers loaded with fluorine containing ciprofloxacin exhibited excellent antimicrobial activity against Pseudomonas aeruginosa biofilm formation. Overall, this innovative stimulus-responsive fluorous biphase drug delivery system will be a promising candidate for practical applications as well as encouraging further investigation of drug delivery and controlled release strategies.

Responsive polymers for medical diagnostics

Stimulus-responsive polymers have been used in improving the efficacy of medical diagnostics through different approaches including enhancing the contrast in imaging techniques and promoting the molecular recognition in diagnostic assays. This review overviews the mechanisms of stimulus-responsive polymers in response to external stimuli including temperature, pH, ion, light, etc. The applications of responsive polymers in magnetic resonance imaging, capture and purification of biomolecules through protein-ligand recognition and lab-on-a-chip technology are discussed.

Absolutely "off-on" fluorescent CD-based nanotheranostics for tumor intracellular real-time imaging and pH-triggered DOX delivery

Carbon dots (CDs) have attracted intense attention in tumor nanotheranostics recently; however, those nanotheranostics exhibited similar fluorescence in both normal and tumor tissues, limiting their practical application. In the present work, absolutely "off-on" fluorescent CD-based nanotheranostics was designed for tumor intracellular real-time imaging and pH-triggered DOX delivery via both static quenching by the crosslinking of benzaldehyde-containing diblock copolymers and dynamic quenching because of the surrounding conjugated DOX molecules. The proposed PPEGMA₄₂-b-PFPMA₁₂₂-(CDs)-DOX nanotheranostics did not exhibit fluorescence in a normal physiological medium, while strong fluorescence recovery occurred in the tumor intracellular microenvironment due to pH-triggered disintegration, releasing the CDs and DOX. The pH-triggered DOX release and absolute "off-on" fluorescence make the proposed nanotheranostics promising for tumor-specific pH-triggered DOX delivery and imaging.

NIR-Triggered Sequentially Responsive Nanocarriers Amplified Cascade Synergistic Effect of Chemo-Photodynamic Therapy with Inspired Antitumor Immunity

A desirable cancer therapeutic strategy is supposed to have effective ability to not only exert maximum anticancer ability but also inspire antitumor immunity for preventing tumor relapse and metastasis. During this research, multifunctional upconversion nanoparticles (UCNPs) coated by ROS-responsive micelles are prepared for tumor targeting and near-infrared (NIR)-triggered photodynamic therapy (PDT)-combined synergistic effect of chemotherapy. Moreover, both PDT and chemotherapy agents could activate antitumor immunity via inducing immunogenic cell death with CD8⁺ and CD4⁺ T cells infiltrating in tumors. Through the experiments, intravenous administration of multifunctional nanocarriers with noninvasive NIR irradiation destroys the orthotopic tumors and efficiently suppresses lung metastasis in a metastatic triple-negative breast cancer model by cascade-amplifying chemo-PDT and systemic antitumor immunity. In conclusion, this study provides prospective chemo-PDT with inspired antitumor immunity for metastatic cancer treatment.

Driving force to detect Alzheimer's disease biomarkers: application of a thioflavine T@Er-MOF ratiometric fluorescent sensor for smart detection of presenilin 1, amyloid β-protein and acetylcholine

Currently, the highly sensitive detection of Alzheimer's Disease (AD) biomarkers, namely presenilin 1, amyloid β-protein (Aβ), and acetylcholine (ACh), is vital to helping us prevent and diagnose AD. In this work, a novel metal-organic framework [Er(L)(DMF)_1.27]_n (Er-MOF) (H₃L = terphenyl-3,4'',5-tricarboxylic acid) has been synthesized by solvothermal and ultrasonic methods. Further, through the post-synthesis assembly strategy, the fluorescent dye thioflavine T (ThT) has been introduced into Er-MOF to construct a dual-emission ThT@Er-MOF ratiometric fluorescent sensor. This is the first time that ThT@Er-MOF has been successfully applied in the highly sensitive detection of three main Alzheimer's disease biomarkers in the cerebrospinal fluid through three different low cost and facile detection strategies. Firstly, with the spilted DNA strategy, this is the first time that ThT@Er-MOF can be applied in the label-free detection of SSODN (part of the presenilin 1 gene). Secondly, for the detection of Aβ, because ThT can be specifically combined with Aβ and has an excellent characteristic fluorescence band, the dual-emission ThT@Er-MOF sensor can be selectively applied to detect Aβ over the analog protein, which shows far more sensitivity than other Aβ sensors. Thirdly, through the acetylcholine esterase (AchE) enzymatic cleavage and release strategy, ThT@Er-MOF enhances the detection of acetylcholine (ACh) with a low limit of detection (LOD) value (0.03226 nM). It should be noticed that the three different detection methods are low cost and facile. This study also provides the first example of utilizing laser scanning confocal microscopy (LSCM) to investigate the fluorescence resonance energy transfer (FRET) detection mechanism by ThT@Er-MOF in more detail. The location of FRET occurrence and FRET efficiency can also be investigated by LSCM, which can be helpful to understand the FRET detection process by these unique MOF-based hybrid materials.

A multifunctional nanomedicine platform for co-delivery of methotrexate and mild hyperthermia towards breast cancer therapy

Methotrexate (MTX), an anti-neoplastic agent used for breast cancer treatment, has restricted clinical applications due to poor water solubility, non-specific targeting and adverse side effects. To overcome these limitations, MTX was co-encapsulated with an active-targeting platform known as superparamagnetic iron oxide nanoparticles (SPIONs) in a lipid-based homing system, nanostructured lipid carrier (NLC). This multi-modal therapeutic regime was successfully formulated with good colloidal stability, bio- and hemo-compatibility. MTX-SPIONs co-loaded NLC was time-dependent cytotoxic towards MDA-MB-231 breast cancer cell line with IC₅₀ values of 137 μg/mL and 12 μg/mL at 48 and 72 h, respectively. The MTX-SPIONs co-loaded NLC was internalized in the MDA-MB-231 cells via caveolae-mediated endocytosis in a time-dependent manner, and the superparamagnetic properties were sufficient to induce, under a magnetic field, a localized temperature increase at cellular level resulting in apoptotic cell death. In conclusion, MTX-SPIONs co-loaded NLC is a potential magnetic guiding multi-modal therapeutic system for the treatment of breast cancer.

Tumor microenvironment responsive drug delivery systems

Conventional tumor-targeted drug delivery systems (DDSs) face challenges, such as unsatisfied systemic circulation, low targeting efficiency, poor tumoral penetration, and uncontrolled drug release. Recently, tumor cellular molecules-triggered DDSs have aroused great interests in addressing such dilemmas. With the introduction of several additional functionalities, the properties of these smart DDSs including size, surface charge and ligand exposure can response to different tumor microenvironments for a more efficient tumor targeting, and eventually achieve desired drug release for an optimized therapeutic efficiency. This review highlights the recent research progresses on smart tumor environment responsive drug delivery systems for targeted drug delivery. Dynamic targeting strategies and functional moieties sensitive to a variety of tumor cellular stimuli, including pH, glutathione, adenosine-triphosphate, reactive oxygen species, enzyme and inflammatory factors are summarized. Special emphasis of this review is placed on their responsive mechanisms, drug loading models, drawbacks and merits. Several typical multi-stimuli responsive DDSs are listed. And the main challenges and potential future development are discussed.

Glycogen as an advantageous polymer carrier in cancer theranostics: Straightforward in vivo evidence

As a natural polysaccharide polymer, glycogen possesses suitable properties for use as a nanoparticle carrier in cancer theranostics. Not only it is inherently biocompatible, it can also be easily chemically modified with various moieties. Synthetic glycogen conjugates can passively accumulate in tumours due to enhanced permeability of tumour vessels and limited lymphatic drainage (the EPR effect). For this study, we developed and examined a glycogen-based carrier containing a gadolinium chelate and near-infrared fluorescent dye. Our aim was to monitor biodistribution and accumulation in tumour-bearing rats using magnetic resonance and fluorescence imaging. Our data clearly show that these conjugates possess suitable imaging and tumour-targeting properties, and are safe under both in vitro and in vivo conditions. Additional modification of glycogen polymers with poly(2-alkyl-2-oxazolines) led to a reduction in the elimination rate and lower uptake in internal organs (lower whole-body background: 45% and 27% lower MRI signals of oxazoline-based conjugates in the liver and kidneys, respectively compared to the unmodified version). Our results highlight the potential of multimodal glycogen-based nanopolymers as a carrier for drug delivery systems in tumour diagnosis and treatment.

Role and Mechanism of Rhizopus Nigrum Polysaccharide EPS1-1 as Pharmaceutical for Therapy of Hepatocellular Carcinoma

Objective: This work is to study the effect of Rhizopus nigrum polysaccharide EPS1-1 on hepatocellular carcinoma (HCC) in vitro and in vivo. Methods: HepG2 and Huh-7 cells and nude mice models of liver cancers were used in this study. The cells and nude mice were treated with EPS1-1 at different concentrations. The CCK8 assays were used to measure the proliferation activities of cells, apoptosis was determined with flow cytometry, cell migration was measured by wound-healing assays, cell invasion was evaluated by Transwell assay, and the survival periods of different groups of tumor-bearing mice were compared. Real-time PCR and Western blot were used to measure the expression levels of mRNAs and proteins of the genes related to proliferation, apoptosis, migration, and invasion. Results: In vitro experiments revealed that when treated with EPS1-1, HepG2 and Huh-7 cell proliferation activities decreased, while there was an increase for the apoptosis rate, and the migration and invasion capabilities were significantly reduced. In vivo experiments showed that EPS1-1 could significantly reduce the tumor growth and lung metastasis of HCC, and prolong the survival periods of tumor-bearing nude mice. Furthermore, EPS1-1 has no apparent damage to the heart, liver, and kidney. Further studies showed that EPS1-1 could affect the expression of proliferation-related genes CCND1 and c-Myc, apoptosis-related genes BAX and Bcl-2, and migration and invasion related genes Vimentin and Slug, thereby affecting the biological process of HCC. Conclusion: EPS1-1 can inhibit the malignant process of HCC in vitro and in vivo, which indicates that EPS1-1 has the potential value of clinical application as chemotherapy or adjuvant in the treatment of liver cancer.

Evaluation of toxicity of halloysite nanotubes and multi-walled carbon nanotubes to endothelial cells in vitro and blood vessels in vivo

Nanomaterials (NMs) with tubular structures, such as halloysite nanotubes (HNTs), have potential applications in biomedicine. Although the biocompatibility of HNTs has been investigated before, the toxicity of HNTs to blood vessels is rarely systemically evaluated. Herein, we compared the toxicity of HNTs and multi-walled carbon nanotubes (MWCNTs) to human umbilical vein endothelial cells (HUVECs) in vitro and blood vessels of mice in vivo. HUVECs internalized HNTs and MWCNTs, but the uptake of HNTs was not obviously changed by clathrin inhibitor. Exposure to NMs decreased cellular viability, activated apoptotic proteins and up-regulated adhesion molecules, including soluble vascular cell adhesion molecule 1 (sVCAM-1) and VCAM-1. As the mechanisms, NMs decreased NO levels, eNOS mRNA and eNOS/p-eNOS proteins. Meanwhile, NMs promoted intracellular ROS and autophagy dysfunction, shown as decreased protein levels of LC3, beclin-1 and ATG5. The eNOS regulator Kruppel-like factor 4 (KLF4) was inhibited, but another eNOS regulator KLF4 was surprisingly up-regulated. Under in vivo conditions, ICR mice intravenously injected with NMs (50 μg/mouse, once a day for 5 days) showed an increased percentage of neutrophils, monocytes and basophils. Meanwhile, autophagy dysfunction, eNOS uncoupling, activation of apoptotic proteins and alteration of KLF proteins were also observed in mouse aortas. All of the toxic effects were more pronounced for MWCNTs in comparison with HNTs based on the same mass concentrations. Our results may provide novel insights about the toxicity of NMs with tubular structures to blood vessels. Considering the toxicological data reported here, HNTs are probably safer nanocarriers compared with MWCNTs.

Graphene Nanoplatelets for the Development of Reinforced PLA-PCL Electrospun Fibers as the Next-Generation of Biomedical Mats

Electrospun scaffolds made of nano- and micro-fibrous non-woven mats from biodegradable polymers have been intensely investigated in recent years. In this field, polymer-based materials are broadly used for biomedical applications since they can be managed in high scale, easily shaped, and chemically changed to tailor their specific biologic properties. Nonetheless polymeric materials can be reinforced with inorganic materials to produce a next-generation composite with improved properties. Herein, the role of graphene nanoplatelets (GNPs) on electrospun poly-l-lactide-co-poly-ε-caprolactone (PLA-PCL, 70:30 molar ratio) fibers was investigated. Microfibers of neat PLA-PCL and with different amounts of GNPs were produced by electrospinning and they were characterized for their physicochemical and biologic properties. Results showed that GNPs concentration notably affected the fibers morphology and diameters distribution, influenced PLA-PCL chain mobility in the crystallization process and tuned the mechanical and thermal properties of the electrospun matrices. GNPs were also liable of slowing down copolymer degradation rate in simulated physiological environment. However, no toxic impurities and degradation products were pointed out up to 60 d incubation. Furthermore, preliminary biologic tests proved the ability of the matrices to enhance fibroblast cells attachment and proliferation probably due to their unique 3D-interconnected structure.

Recent Trends in Applying Rrtho-Nitrobenzyl Esters for the Design of Photo-Responsive Polymer Networks

Polymers with light-responsive groups have gained increased attention in the design of functional materials, as they allow changes in polymers properties, on demand, and simply by light exposure. For the synthesis of polymers and polymer networks with photolabile properties, the introduction o-nitrobenzyl alcohol (o-NB) derivatives as light-responsive chromophores has become a convenient and powerful route. Although o-NB groups were successfully exploited in numerous applications, this review pays particular attention to the studies in which they were included as photo-responsive moieties in thin polymer films and functional polymer coatings. The review is divided into four different sections according to the chemical structure of the polymer networks: (i) acrylate and methacrylate; (ii) thiol-click; (iii) epoxy; and (iv) polydimethylsiloxane. We conclude with an outlook of the present challenges and future perspectives of the versatile and unique features of o-NB chemistry.