Photo-tunable protein release from biodegradable nanoparticles composed of cinnamic acid derivatives

Protein diffusion from microwells with contrasting hydrogel domains

Understanding and controlling molecular transport in hydrogel materials is important for biomedical tools, including engineered tissues and drug delivery, as well as life sciences tools for single-cell analysis. Here, we scrutinize the ability of microwells-micromolded in hydrogel slabs-to compartmentalize lysate from single cells. We consider both (i) microwells that are "open" to a large fluid (i.e., liquid) reservoir and (ii) microwells that are "closed," having been capped with either a slab of high-density polyacrylamide gel or an impermeable glass slide. We use numerical modeling to gain insight into the sensitivity of time-dependent protein concentration distributions on hydrogel partition and protein diffusion coefficients and open and closed microwell configurations. We are primarily concerned with diffusion-driven protein loss from the microwell cavity. Even for closed microwells, confocal fluorescence microscopy reports that a fluid (i.e., liquid) film forms between the hydrogel slabs (median thickness of 1.7 μm). Proteins diffuse from the microwells and into the fluid (i.e., liquid) layer, yet concentration distributions are sensitive to the lid layer partition coefficients and the protein diffusion coefficient. The application of a glass lid or a dense hydrogel retains protein in the microwell, increasing the protein solute concentration in the microwell by ∼7-fold for the first 15 s. Using triggered release of Protein G from microparticles, we validate our simulations by characterizing protein diffusion in a microwell capped with a high-density polyacrylamide gel lid (p > 0.05, Kolmogorov-Smirnov test). Here, we establish and validate a numerical model useful for understanding protein transport in and losses from a hydrogel microwell across a range of boundary conditions.

Cinnamic acid derivatives as promising building blocks for advanced polymers: synthesis, properties and applications

A global overview of the use of cinnamic acid derivatives in polymer science is given in this review paper.

Synthesis, thermal properties and cell-compatibility of photocrosslinked cinnamoyl-modified hydroxypropyl cellulose

Biocompatibility of cinnamoyl-modified carbohydrate materials is not well-known, while they are attracting attention as a photoreactive material. In order to investigate biocompatible properties of cinnamoyl-modified carbohydrate, hydroxypropyl cellulose (HPC) was reacted with cinnamoyl chloride to yield cinnamoyl-modified HPC (HPC-C) for a cell proliferation test. HPC-Cs with three different degrees of substitution (DS) were prepared by changing a feed ratio of cinnamoyl chloride to HPC. The DS of the products ranged from 1.3 to 3.0 per one hydroxylpropyl anhydroglucose unit. Thermal analysis using DSC and TGA showed that the HPC-C with higher DS has a glass transition temperature and higher thermal stability. Ultraviolet (UV) light was irradiated on the HPC-C thin films, and changes in the UV-vis spectrum of the films were examined. In the course of UV irradiation, the absorbance at 280 nm was reduced. Fibroblast cells were cultured on the photocrosslinked HPC-C films, and cell growth was examined. The cell proliferation test revealed that the photocrosslinked HPC-C films have good compatibility with fibroblast cells.

Photo-switchable nanoporous silica supports for controlled drug delivery

A stimuli-responsive drug delivery system consisting of SBA-12 nanoporous silica modified with a photo-switchable coumarin ligand was studied for the delivery of the non-steroidal anti-inflammatory drug naproxen.

Light-triggered release from dye-loaded fluorescent lipid nanocarriers in vitro and in vivo

Light is an attractive trigger for release of active molecules from nanocarriers in biological systems. Here, we describe a phenomenon of light-induced release of a fluorescent dye from lipid nano-droplets under visible light conditions. Using auto-emulsification process we prepared nanoemulsion droplets of 32nm size encapsulating the hydrophobic analogue of Nile Red, NR668. While these nano-droplets cannot spontaneously enter the cells on the time scale of hours, after illumination for 30s under the microscope at the wavelength of NR668 absorption (535nm), the dye showed fast accumulation inside the cells. The same phenomenon was observed in zebrafish, where nano-droplets initially staining the blood circulation were released into endothelial cells and tissues after illumination. Fluorescence correlation spectroscopy revealed that laser illumination at relatively low power (60mW/cm²) could trigger the release of the dye into recipient media, such as 10% serum or blank lipid nanocarriers. The photo-release can be inhibited by deoxygenation with sodium sulfite, suggesting that at least in part the release could be related to a photochemical process involving oxygen, though a photo-thermal effect could also take place. Finally, we showed that illumination of NR668 can provoke the release into the cells of another highly hydrophobic dye co-encapsulated into the lipid nanocarriers. These results suggest dye-loaded lipid nano-droplets as a prospective platform for preparation of light-triggered nanocarriers of active molecules.

Field responsive materials: photo-, electro-, magnetic- and ultrasound-sensitive polymers

Recent advances in field-responsive polymers, which have emerged as highly promising materials for numerous applications, are highlighted.

A drug delivery system based on switchable photo-controlled p-coumaric acid derivatives anchored on mesoporous silica

Mesoporous silica modified by p-coumaric acid derivatives as photo-switchable ligands was studied for the delivery of a non-steroidal anti-inflammatory drug.

Fabrication of Biobased Polyelectrolyte Capsules and Their Application for Glucose-Triggered Insulin Delivery

To enhance the glucose sensitivity and self-regulated release of insulin, biobased capsules with glucose-responsive and competitive properties were fabricated based on poly(γ-glutamic acid) (γ-PGA) and chitosan oligosaccharide (CS) polyelectrolytes. First, poly(γ-glutamic acid)-g-3-aminophenylboronic acid) (γ-PGA-g-APBA) and galactosylated chitosan oligosaccharide (GC) were synthesized by grafting APBA and lactobionic acid (LA) to γ-PGA and CS, respectively. The (γ-PGA-g-APBA/GC)5 capsules were then prepared by layer-by-layer (LBL) assembly of γ-PGA-g-APBA and GC via electrostatic interaction. The size and morphology of the particles and capsules were investigated by DLS, SEM, and TEM. The size of the (γ-PGA-g-APBA/GC)5 capsules increased with increasing glucose concentration due to the swelling of the capsules. The capsules could be dissociated at high glucose concentration due to the breaking of the cross-linking bonds between APBA and LA by the competitive reaction of APBA with glucose. The encapsulated insulin was able to undergo self-regulated release from the capsules depending on the glucose level and APBA composition. The amount of insulin release increased with incubation in higher glucose concentration and decreased with higher APBA composition. Moreover, the on-off regulation of insulin release from the (γ-PGA-g-APBA/GC)5 capsules could be triggered with a synchronizing and variation of the external glucose concentration, whereas the capsules without the LA functional groups did not show the on-off regulated release. Furthermore, the (γ-PGA-g-APBA/GC)5 capsules are biocompatible. These (γ-PGA-g-APBA/GC)5 with good stability, glucose response, and controlled insulin delivery are expected to be used for future applications to glucose-triggered insulin delivery.

Photoresponsive nanoparticles for drug delivery

Externally triggerable drug delivery systems provide a strategy for the delivery of therapeutic agents preferentially to a target site, presenting the ability to enhance therapeutic efficacy while reducing side effects. Light is a versatile and easily tuned external stimulus that can provide spatiotemporal control. Here we will review the use of nanoparticles in which light triggers drug release or induces particle binding to tissues (phototargeting).

Nanobiocatalyst advancements and bioprocessing applications

The nanobiocatalyst (NBC) is an emerging innovation that synergistically integrates advanced nanotechnology with biotechnology and promises exciting advantages for improving enzyme activity, stability, capability and engineering performances in bioprocessing applications. NBCs are fabricated by immobilizing enzymes with functional nanomaterials as enzyme carriers or containers. In this paper, we review the recent developments of novel nanocarriers/nanocontainers with advanced hierarchical porous structures for retaining enzymes, such as nanofibres (NFs), mesoporous nanocarriers and nanocages. Strategies for immobilizing enzymes onto nanocarriers made from polymers, silicas, carbons and metals by physical adsorption, covalent binding, cross-linking or specific ligand spacers are discussed. The resulting NBCs are critically evaluated in terms of their bioprocessing performances. Excellent performances are demonstrated through enhanced NBC catalytic activity and stability due to conformational changes upon immobilization and localized nanoenvironments, and NBC reutilization by assembling magnetic nanoparticles into NBCs to defray the high operational costs associated with enzyme production and nanocarrier synthesis. We also highlight several challenges associated with the NBC-driven bioprocess applications, including the maturation of large-scale nanocarrier synthesis, design and development of bioreactors to accommodate NBCs, and long-term operations of NBCs. We suggest these challenges are to be addressed through joint collaboration of chemists, engineers and material scientists. Finally, we have demonstrated the great potential of NBCs in manufacturing bioprocesses in the near future through successful laboratory trials of NBCs in carbohydrate hydrolysis, biofuel production and biotransformation.

Synthesis of drug-crosslinked polymer nanoparticles

A new kind of drug-crosslinked polymer nanoparticle was synthesized. The nanoparticles were composed by a phenylboronic acid modified 10-hydroxycamptothecin (the crosslinker) and 1,2-diol-rich PEG-PGMA diblock copolymer (the backbone), and crosslinked by phenylboronic ester bond.

Fabrication of rod-like nanocapsules based on polylactide and 3,4-dihydroxyphenylalanine for a drug delivery system

Rod-like nanocapsules were facilely fabricated based on a bio-based polymer via DOPA adhesion. The nanocapsules showed high drug-loading efficacies and controlled drug release depending on different pH buffer solutions.

A facile strategy to generate polymeric nanoparticles for synergistic chemo-photodynamic therapy

Polymeric nanoparticles generated by mPEG-tetrakis(4-carboxyphenyl)porphyrin amphiphiles were used to trap doxorubicin for synergistic chemo-photodynamic therapy.

Drug-loaded sickle cells programmed ex vivo for delayed hemolysis target hypoxic tumor microvessels and augment tumor drug delivery

Selective drug delivery to hypoxic tumor niches remains a significant therapeutic challenge that calls for new conceptual approaches. Sickle red blood cells (SSRBCs) have shown an ability to target such hypoxic niches and induce tumoricidal effects when used together with exogenous pro-oxidants. Here we determine whether the delivery of a model therapeutic encapsulated in murine SSRBCs can be enhanced by ex vivo photosensitization under conditions that delay autohemolysis to a time that coincides with maximal localization of SSRBCs in a hypoxic tumor. Hyperspectral imaging of 4T1 carcinomas shows oxygen saturation levels <10% in a large fraction (commonly 50% or more) of the tumor. Using video microscopy of dorsal skin window chambers implanted with 4T1 tumors, we demonstrate that allogeneic SSRBCs, but not normal RBCs (nRBCs), selectively accumulate in hypoxic 4T1 tumors between 12 and 24h after systemic administration. We further show that ex vivo photo-oxidation can program SSRBCs to postpone hemolysis/release of a model therapeutic to a point that coincides with their maximum sequestration in hypoxic tumor microvessels. Under these conditions, drug-loaded photosensitized SSRBCs show a 3-4 fold greater drug delivery to tumors compared to non-photosensitized SSRBCs, drug-loaded photosensitized nRBCs, and free drug. These results demonstrate that photo-oxidized SSRBCs, but not photo-oxidized nRBCs, sequester and hemolyze in hypoxic tumors and release substantially more drug than photo-oxidized nRBCs and non-photo-oxidized SSRBCs. Photo-oxidation of drug-loaded SSRBCs thus appears to exploit the unique tumor targeting and carrier properties of SSRBCs to optimize drug delivery to hypoxic tumors. Such programmed and drug-loaded SSRBCs therefore represent a novel and useful tool for augmenting drug delivery to hypoxic solid tumors.

Photodegradable polyurethane self-assembled nanoparticles for photocontrollable release

Light-responsive drug delivery systems are particularly appealing that are capable of releasing active molecules at the appropriate site and rate. We synthesized a series of photodegradable polymers that can form nanoparticles for drug encapsulation. These particles in aqueous solutions are stable in buffers with different pHs or at evaluated temperatures, while light can trigger the crash of particles and the release of encapsulated substances. The release efficiency can reach up to 90% based on Nile red fluorescence intensity upon 15 min light irradiation. Nanoparticle uptake by phagocytic cells and light-triggered release in cells were observed by fluorescence emission of the hydrolyzed fluorescein diacetate upon photoinduced degradation of these nanoparticles. No significant toxicity of these nanoparticles was found at the concentrations up to 1000 μg/mL before or after light irradiation. Further encapsulation and triggered release of a bioactive model drug (Tagalsin G) was evaluated for RAW 264.7 cells. Tagalsin G encapsulated in nanoparticles did not show cytotoxity to cells, while light triggered the release of Tagalsin G increasing cell death dramatically from 9% to 67%. Our model studies show a new promising strategy to trigger drug release in cells.

Design, synthesis, and miniemulsion polymerization of new phosphonate surfmers and application studies of the resulting nanoparticles as model systems for biomimetic mineralization and cellular uptake

Heterophase polymerizations have gained increasing attention in the past decades, especially as the decoration and functionalization of the particle surface for further applications gets more and more into focus. One promising approach for the functionalization exclusively on the particle surface is the use of surfmers (surfactant and monomer). Herein, we present the synthesis of a new family of surfmers and their use for decorating nanoparticles with phosphonate groups through miniemulsion polymerization. Furthermore the synthesis of a dye-labeled functional surfmer provided an elegant manner to evaluate and get deeper insights about its copolymerization. Additionally, potential applications of the synthesized particles in biological studies as well as their use as template for biomimetic mineralization are presented.