Dendrimer and dendrimer–conjugate protein complexes and protein coronas

Dendrimers and dendrimer conjugates are widely employed for biological applications such as bio-imaging and drug delivery. Understanding the interaction between dendrimers and their biological environment is key to evaluating the efficacy and safety of these materials. Proteins can form an adsorbed layer, termed a “protein corona”, on dendrimers in either a non-specific or specific fashion. A tight-binding, non-exchangeable corona is defined as a “hard” corona, whereas a loosely bound, highly exchangeable corona is called a “soft” corona. Recent research indicates that small molecules conjugated to the polymer surface can induce protein structural change, leading to tighter protein–dendrimer binding and further protein aggregation. This “triggered” corona formation on dendrimer and dendrimer conjugates is reviewed and discussed along with the existing hard or soft corona model. This review describes the triggered corona model to further the understanding of protein corona formation.

In vitro and in vivo evaluation of effectiveness of a novel TEMPO-oxidized cellulose nanofiber-silk fibroin scaffold in wound healing

In this study, a novel TEMPO-oxidized cellulose nanofiber (TOCN)-silk fibroin scaffold was prepared using a cost effective freeze drying method. Fundamental physical characterizations were carried out by scanning electron microscopy (SEM), pore diameter determination, FT-IR. PBS uptake behavior of the scaffold showed that, silk fibroin can enhance the swelling capacity of TOCN. L929 primary fibroblast cell was selected for in vitro studies, which showed that the scaffolds facilitated growth of cells. In vivo evaluation of TOCN, TOCN-silk fibroin composites was examined using critical sized rat skin excisional model for one and two weeks. The results of rat wound model revealed that, compared to only TOCN scaffold, TOCN-silk fibroin scaffold successfully promoted wound healing by the expression of wound healing markers. TOCN-silk fibroin 2% has the fastest wound healing capacity. Thus, it appears that TOCN-silk fibroin composite scaffolds can be useful as wound healing material in clinical applications.

Advances and perspectives in tooth tissue engineering

Bio-engineered teeth that can grow and remodel in a manner similar to that of natural teeth have the potential to serve as permanent replacements to the currently used prosthetic teeth, such as dental implants. A major challenge in designing functional bio-engineered teeth is to mimic both the structural and anisotropic mechanical characteristics of the native tooth. Therefore, the field of dental and whole tooth regeneration has advanced towards the molecular and nanoscale design of bio-active, biomimetic systems, using biomaterials, drug delivery systems and stem cells. The focus of this review is to discuss recent advances in tooth tissue engineering, using biomimetic scaffolds that provide proper architectural cues, exhibit the capacity to support dental stem cell proliferation and differentiation and sequester and release bio-active agents, such as growth factors and nucleic acids, in a spatiotemporal controlled manner. Although many in vitro and in vivo studies on tooth regeneration appear promising, before tooth tissue engineering becomes a reality for humans, additional research is needed to perfect methods that use adult human dental stem cells, as opposed to embryonic dental stem cells, and to devise the means to generate bio-engineered teeth of predetermined size and shape. Copyright © 2016 John Wiley & Sons, Ltd.

Hot Melt Extrudates Formulated Using Design Space: One Simple Process for Both Palatability and Dissolution Rate Improvement

This work aimed at obtaining an optimized itraconazole (ITZ) solid oral formulation in terms of palatability and dissolution rate by combining different polymers using hot melt extrusion (HME), according to a simplex centroid mixture design. For this, the polymers Plasdone^® (poly(1-vinylpyrrolidone-co-vinyl acetate) [PVP/VA]), Klucel^® ELF (2-hydroxypropyl ether cellulose [HPC]), and Soluplus^® (SOL, polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol) were processed using a laboratory HME equipment operating without recirculation at constant temperature. Samples were characterized by physicochemical assays, as well as dissolution rate and palatability using an e-tongue. All materials became homogeneous and dense after HME processing. Thermal and structural analyses demonstrated drug amorphization, whereas IR spectroscopy evidenced drug stability and drug-excipient interactions in HME systems. Extrudates presented a significant increase in dissolution rate compared to ITZ raw material, mainly with formulations containing PVP/VA and HPC. A pronounced improvement in taste masking was also identified for HME systems, especially in those containing higher amounts of SOL and HPC. Data showed polymers act synergistically favoring formulation functional properties. Predicted best formulation should contain ITZ 25.0%, SOL 33.2%, HPC 28.9%, and PVP/VA 12.9% (w/w). Optimized response considering dissolution rate and palatability reinforces the benefit of polymer combinations.

Synthesis and gelation of copolypept(o)ides with random and block structure

Copolypept(o)ides of polysarcosine (PSar) and poly(N-isopropyl-L-glutamine) (PIGA) with random and block sequence structures were synthesized by ring-opening polymerization (ROP) of sarcosine N-carboxyanhydrides (Sar-NCA) and γ-benzyl-l-glutamate N-carboxyanhydrides (BLG-NCA) and post modification. With different distribution of Sar along the main chain, H-bonding pattern and secondary structure of polypeptides were turned, as well as aggregation and gelation behavior. Both copolypept(o)ides formed hydrogels above their critical gelation concentrations (CGCs) without thermo-sensitivity, which was normally reserved for PEG copolypeptides (eg, PEG-b-PIGA). In particular, a different mechanism from previously reported micellar percolation or fibrillar entanglement was suggested for gelation of the random copolypept(o)ide. Therefore, hydrogels from copolymers of PSar and PIGA represented a new approach to construct easy-handling, biocompatible, biodegradable and thermo-stable gels that could potentially be applied in biomedical fields.

Cholesterol-Appended Benzimidazolium Salts: Synthesis, Aggregation, Sensing, Dye Adsorption, and Semiconducting Properties

A series of cholesterol-appended benzimidazolium salts 1-9 have been designed and synthesized. They have been explored in gel chemistry. The gelation of the benzimidazolium salts is dependent on the nature of the counteranions. In addition, the gelation behavior of the gelators is linked with the presence of both π-stacking and cholesteryl motifs. Whereas bisbenzimidazolium salt 2 forms a gel in dimethylsulfoxide/H₂O (1:1, v/v) itself, under similar conditions, monobenzimidazolium salts 4 and 6 exhibit gelation in the presence of F^- ions and validate the visual sensing of F^-. As an application, the gel phase of 2 efficiently removes toxic dyes from waste water. Furthermore, all gels show thermally activated semiconducting property within a wide voltage window.

Effects of free radical initiators on polyethylene glycol dimethacrylate hydrogel properties and biocompatibility

Many studies have utilized Irgacure 2959 photopolymerized poly(ethylene glycol) (PEG) hydrogels for tissue engineering application development. Due to the limited penetration of ultraviolet light through tissue, Irgacure 2959 polymerized hydrogels are not suitable for use in tissues where material injection is desirable, such as the spinal cord. To address this, several free radical initiators (thermal initiator VA044, ammonium persulfate (APS)/TEMED reduction-oxidation reaction, and Fenton chemistry) are evaluated for their effects on the material and mechanical properties of PEG hydrogels compared with Irgacure 2959. To emulate the effects of endogenous thiols on in vivo polymerization, the effects of chain transfer agent (CTA) dithiothreitol on gelation rates, material properties, Young's and shear modulus, are examined. Mouse embryonic stem cells and human induced pluripotent stem cell derived neural stem cells were used to investigate the cytocompatibility of each polymerization. VA044 and Fenton chemistry polymerization of PEG hydrogels both had gelation rates and mechanical properties that were highly susceptible to changes in CTA concentration and showed poor cytocompatibility. APS/TEMED polymerized hydrogels maintained consistent gelation rates and mechanical properties at high CTA concentration and had a similar cytocompatibility as Irgacure 2959 when cells were encapsulated within the PEG hydrogels. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3059-3068, 2017.

RGD Peptide-Based Target Drug Delivery of Doxorubicin Nanomedicine

Preclinical Research Doxorubicin (DOX) is commonly used for the treatment of breast cancer and lymphoma. However, its clinical use has been severely limited due to cardiotoxicity, requiring the development of safer and more efficient pharmaceutical formulations of DOX. Advances in nanotechnology have provided new ways to administer chemotherapeutic drugs like DOX are conveyed into the body and to tumor sites. These Nanotechnology approaches have aided in the selective accumulation of DOX into tumor sites via the enhanced permeability and retention. However, the absence of active targeting ligands still hinders the effective delivery of DOX. Among all active targeting ligands developed to date, RGD peptide (Arginylglycylaspartic acid) occupies a unique position owing to its inherent safety, biocompatibility, and targeting ability. Accordingly, modification of DOX with RGD ligand is anticipated to improve transport of DOX into tumor cells. In this review, we discuss using RGD peptide for improving the therapeutic efficacy of DOX nanomedicine. Drug Dev Res 78 : 283-291, 2017. © 2017 Wiley Periodicals, Inc.

* Three-Dimensional Bioprinting of Polycaprolactone Reinforced Gene Activated Bioinks for Bone Tissue Engineering

Regeneration of complex bone defects remains a significant clinical challenge. Multi-tool biofabrication has permitted the combination of various biomaterials to create multifaceted composites with tailorable mechanical properties and spatially controlled biological function. In this study we sought to use bioprinting to engineer nonviral gene activated constructs reinforced by polymeric micro-filaments. A gene activated bioink was developed using RGD-γ-irradiated alginate and nano-hydroxyapatite (nHA) complexed to plasmid DNA (pDNA). This ink was combined with bone marrow-derived mesenchymal stem cells (MSCs) and then co-printed with a polycaprolactone supporting mesh to provide mechanical stability to the construct. Reporter genes were first used to demonstrate successful cell transfection using this system, with sustained expression of the transgene detected over 14 days postbioprinting. Delivery of a combination of therapeutic genes encoding for bone morphogenic protein and transforming growth factor promoted robust osteogenesis of encapsulated MSCs in vitro, with enhanced levels of matrix deposition and mineralization observed following the incorporation of therapeutic pDNA. Gene activated MSC-laden constructs were then implanted subcutaneously, directly postfabrication, and were found to support superior levels of vascularization and mineralization compared to cell-free controls. These results validate the use of a gene activated bioink to impart biological functionality to three-dimensional bioprinted constructs.

Dual tumor-targeted poly(lactic-co-glycolic acid)-polyethylene glycol-folic acid nanoparticles: a novel biodegradable nanocarrier for secure and efficient antitumor drug delivery

Further specific target-ability development of biodegradable nanocarriers is extremely important to promote their security and efficiency in antitumor drug-delivery applications. In this study, a facilely prepared poly(lactic-co-glycolic acid) (PLGA)-polyethylene glycol (PEG)-folic acid (FA) copolymer was able to self-assemble into nanoparticles with favorable hydrodynamic diameters of around 100 nm and negative surface charge in aqueous solution, which was expected to enhance intracellular antitumor drug delivery by advanced dual tumor-target effects, ie, enhanced permeability and retention induced the passive target, and FA mediated the positive target. Fluorescence-activated cell-sorting and confocal laser-scanning microscopy results confirmed that doxorubicin (model drug) loaded into PLGA-PEG-FA nanoparticles was able to be delivered efficiently into tumor cells and accumulated at nuclei. In addition, all hemolysis, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, and zebrafish-development experiments demonstrated that PLGA-PEG-FA nanoparticles were biocompatible and secure for biomedical applications, even at high polymer concentration (0.1 mg/mL), both in vitro and in vivo. Therefore, PLGA-PEG-FA nanoparticles provide a feasible controlled-release platform for secure and efficient antitumor drug delivery.

Supersensitive Oxidation-Responsive Biodegradable PEG Hydrogels for Glucose-Triggered Insulin Delivery

Reactive oxygen species (ROS)-responsive polymers and hydrogels represent an emerging family of intelligent materials owing to the key functions of ROS in physiological processes or pathological diseases. Nonetheless, the weaknesses such as low sensitivity, slow response, instability, and low mechanical strength are associated with the limited ROS-responsive polymeric or supramolecular hydrogels. In this study, a novel type of oxidation-responsive degradable hydrogels was fabricated by the redox-initiated radical polymerization of a 4-arm-poly(ethylene glycol) (PEG) acrylic macromonomer that possesses a H₂O₂-cleavable phenylboronic acid linker in each of the arms. The macroscopic hydrogels have the features of good cytocompatibility, moderate mechanical strength, and fast response toward H₂O₂ of low concentration, owing to the covalently cross-linked hydrophilic PEG network and high sensitivity of the linker. They could encapsulate biomacromolecules, such as insulin and glucose oxidase (GOx), with high efficacy, affording a new glucose-responsive insulin-delivery platform on the basis of enzymatic transformation of a biochemical signal (glucose) into an oxidative stimulus (H₂O₂). Interestingly, in vitro results demonstrate that the same GOx-loaded hydrogel exhibited disparate degradation modes under different triggering molecules, that is, bulk degradation by H₂O₂ and surface erosion by glucose. Moreover, compared to the macroscopic hydrogel, the nanogel with a diameter of ∼160 nm prepared by inverse emulsion polymerization showed a much higher degradation rate even under triggering of 20 μM H₂O₂, a pathologically available concentration in vivo.

druGAN: An Advanced Generative Adversarial Autoencoder Model for de Novo Generation of New Molecules with Desired Molecular Properties in Silico

Deep generative adversarial networks (GANs) are the emerging technology in drug discovery and biomarker development. In our recent work, we demonstrated a proof-of-concept of implementing deep generative adversarial autoencoder (AAE) to identify new molecular fingerprints with predefined anticancer properties. Another popular generative model is the variational autoencoder (VAE), which is based on deep neural architectures. In this work, we developed an advanced AAE model for molecular feature extraction problems, and demonstrated its advantages compared to VAE in terms of (a) adjustability in generating molecular fingerprints; (b) capacity of processing very large molecular data sets; and (c) efficiency in unsupervised pretraining for regression model. Our results suggest that the proposed AAE model significantly enhances the capacity and efficiency of development of the new molecules with specific anticancer properties using the deep generative models.

pH-responsive self-healing injectable hydrogel based on N-carboxyethyl chitosan for hepatocellular carcinoma therapy

Injectable hydrogels with pH-responsiveness and self-healing ability have great potential for anti-cancer drug delivery. Herein, we developed a series of polysaccharide-based self-healing hydrogels with pH-sensitivity as drug delivery vehicles for hepatocellular carcinoma therapy. The hydrogels were prepared by using N-carboxyethyl chitosan (CEC) synthesized via Michael reaction in aqueous solution and dibenzaldehyde-terminated poly(ethylene glycol) (PEGDA). Doxorubicin (Dox), as a model of water-soluble small molecule anti-cancer drug was encapsulated into the hydrogel in situ. Self-healing behavior of the hydrogels was investigated at microscopic and macroscopic levels, and the hydrogels showed rapid self-healing performance without any external stimulus owing to the dynamic covalent Schiff-base linkage between amine groups from CEC and benzaldehyde groups from PEGDA. The chemical structures, rheological property, in vitro gel degradation, morphology, gelation time and in vitro Dox release behavior from the hydrogels were characterized. Injectability was verified by in vitro injection and in vivo subcutaneous injection in a rat. pH-responsive behavior was verified by in vitro Dox release from hydrogels in PBS solutions with different pH values. Furthermore, the activity of Dox released from hydrogel matrix was evaluated by employing human hepatocellular liver carcinoma (HepG2). Cytotoxicity test of the hydrogels using L929 cells confirmed their good cytocompatibility. Together, these pH-responsive self-healing injectable hydrogels are excellent candidates as drug delivery vehicles for liver cancer treatment. STATEMENT OF SIGNIFICANCE: pH-responsive drug delivery system could release drug efficiently in targeted acid environment and minimalize the amount of drug release in normal physiological environment. pH-sensitive injectable hydrogels as smart anti-cancer drug delivery carriers show great potential application for cancer therapy. The hydrogels with self-healing property could prolong their lifetime during implantation and provide the advantage of minimally invasive surgery and high drug-loading ratio. This work reported the design of a series of pH-responsive self-healing injectable hydrogels based on N-carboxyethyl chitosan synthesized in aqueous solution and dibenzaldehyde-terminated poly(ethylene glycol) via a green approach, and demonstrated their potential as intelligent delivery vehicle of doxorubicin for hepatocellular carcinoma therapy via the pH-responsive nature of dynamic Schiff base.

Topical application of palmitoyl-RGD reduces human facial wrinkle formation in Korean women

Maintaining a youthful appearance is a common desire among the aging population. Loss of elasticity and dermal density constitutes major causes of wrinkle formation during skin aging. In particular, periorbital wrinkles comprise the critical assessment point of skin aging. To address these issues, cosmetic industries have been making increasing efforts to develop efficient agents against wrinkle formation. Arg-Gly-Asp (RGD) is a tripeptide sequence used for surface coating because of its integrin-binding property. However, its pharmacological properties on skin have not yet been studied. Here, we synthesize the novel palmitoyl-Arg-Gly-Asp (Palm-RGD) and investigate its effects on periorbital wrinkle formation by clinical and in vitro studies. We observed that Palm-RGD cream application for 12 weeks decreased global photodamage and skin roughness (R1, R2, R3, and Ra) scores without causing skin irritation. In addition, topical application of Palm-RGD cream time-dependently increased skin elasticity and dermal density. An in vitro study using human dermal fibroblasts (HDFs) demonstrated increased type I procollagen production by Palm-RGD treatment. Furthermore, Palm-RGD suppressed MMP-1 expression in HDFs. Our results demonstrate that Palm-RGD has protective effects against wrinkle formation, likely through the activation of collagen expression and the protection against collagen degradation. Therefore, Palm-RGD could be used as a potential agent for the prevention of wrinkle formation consequent to aging.

Drug Discovery by Molecular Imaging and Monitoring Therapy Response in Lymphoma

Molecular imaging allows a noninvasive assessment of biochemical and biological processes in living subjects. Treatment strategies for malignant lymphoma depend on histology and tumor stage. For the last two decades, molecular imaging has been the mainstay diagnostic test for the staging of malignant lymphoma and the assessment of response to treatment. This technology enhances our understanding of disease and drug activity during preclinical and clinical drug development. Here, we review molecular imaging applications in drug development, with an emphasis on oncology. Monitoring and assessing the efficacy of anti-cancer therapies in preclinical or clinical models are essential and the multimodal molecular imaging approach may represent a new stage for pharmacologic development in cancer. Monitoring the progress of lymphoma therapy with imaging modalities will help patients. Identifying and addressing key challenges is essential for successful integration of molecular imaging into the drug development process. In this review, we highlight the general usefulness of molecular imaging in drug development and radionuclide-based reporter genes. Further, we discuss the different molecular imaging modalities for lymphoma therapy and their preclinical and clinical applications.

Covalently adaptable elastin-like protein - hyaluronic acid (ELP - HA) hybrid hydrogels with secondary thermoresponsive crosslinking for injectable stem cell delivery

Shear-thinning, self-healing hydrogels are promising vehicles for therapeutic cargo delivery due to their ability to be injected using minimally invasive surgical procedures. We present an injectable hydrogel using a novel combination of dynamic covalent crosslinking with thermoresponsive engineered proteins. Ex situ at room temperature, rapid gelation occurs through dynamic covalent hydrazone bonds by simply mixing two components: hydrazine-modified elastin-like protein (ELP) and aldehyde-modified hyaluronic acid. This hydrogel provides significant mechanical protection to encapsulated human mesenchymal stem cells during syringe needle injection and rapidly recovers after injection to retain the cells homogeneously within a 3D environment. In situ, the ELP undergoes a thermal phase transition, as confirmed by Coherent anti-Stokes Raman scattering microscopy observation of dense ELP thermal aggregates. The formation of the secondary network reinforces the hydrogel and results in a 10-fold slower erosion rate compared to a control hydrogel without secondary thermal crosslinking. This improved structural integrity enables cell culture for three weeks post injection, and encapsulated cells maintain their ability to differentiate into multiple lineages, including chondrogenic, adipogenic, and osteogenic cell types. Together, these data demonstrate the promising potential of ELP-HA hydrogels for injectable stem cell transplantation and tissue regeneration.

Block copolymer conjugated Au-coated Fe3O4 nanoparticles as vectors for enhancing colloidal stability and cellular uptake

BACKGROUND

Polymer surface-modified inorganic nanoparticles (NPs) provide a multifunctional platform for assisting gene delivery. Rational structure design for enhancing colloidal stability and cellular uptake is an important strategy in the development of safe and highly efficient gene vectors.

RESULTS

Heterogeneous Au-coated Fe3O4 (Fe3O4@Au) NPs capped by polyethylene glycol-b-poly1-(3-aminopropyl)-3-(2-methacryloyloxy propylimidazolium bromine) (PEG-b-PAMPImB-Fe3O4@Au) were prepared for DNA loading and magnetofection assays. The Au outer shell of the NPs is an effective platform for maintaining the superparamagnetism of Fe3O4 and for PEG-b-PAMPImB binding via Au-S covalent bonds. By forming an electrostatic complex with DNA at the inner PAMPImB shell, the magnetic nanoplexes offer steric protection from the outer corona PEG, thereby promoting high colloidal stability. Transfection efficiency assays in human esophageal cancer cells (EC109) show that the nanoplexes have high transfection efficiency at a short incubation time in the presence of an external magnetic field, due to increased cellular internalization via magnetic acceleration. Finally, after transfection with the magnetic nanoplexes EC109 cells acquire magnetic properties, thus allowing for selective separation of transfected cells.

CONCLUSION

Precisely engineered architectures based on neutral-cationic block copolymer-conjugated heterogeneous NPs provide a valuable strategy for improving the applicability and efficacy of synthesized vectors.

Development of a clay based bioink for 3D cell printing for skeletal application

Three-dimensional printing of cell-laden hydrogels has evolved as a promising approach on the route to patient-specific or complex tissue-engineered constructs. However, it is still challenging to print structures with both, high shape fidelity and cell vitality. Herein, we used a synthetic nanosilicate clay, called Laponite, to build up scaffolds utilising the extrusion-based method 3D plotting. By blending with alginate and methylcellulose, a bioink was developed which allowed easy extrusion, achieving scaffolds with high printing fidelity. Following extrusion, approximately 70%-75% of printed immortalised human mesenchymal stem cells survived and cell viability was maintained over 21 days within the plotted constructs. Mechanical properties of scaffolds comprised of the composite bioink decreased over time when stored under cell culture conditions. Nevertheless, shape of the plotted constructs was preserved even over longer cultivation periods. Laponite is known for its favourable drug delivery properties. Two model proteins, bovine serum albumin and vascular endothelial growth factor were loaded into the bioink. We demonstrate that the release of both growth factors significantly changed to a more sustained profile by inclusion of Laponite in comparison to an alginate-methylcellulose blend in the absence of Laponite. In summary, addition of a synthetic clay, Laponite, improved printability, increased shape fidelity and was beneficial for controlled release of biologically active agents such as growth factors.

The mechanical properties of polymer-colloid hybrid hydrogels

The incorporation of monodisperse colloidal particles in hydrogels is a promising approach to create hybrid gels with unique structural, mechanical and functional properties. However, the colloidal structure formation within the hydrogels often remains uncontrolled, leaving behind possible mechanically synergetic effects of the polymeric and the colloidal system. Here we show that colloidal structure formation within the hybrid gels has a significant influence on the elasticity and toughness of the hybrid gels. We combine a polyacrylamide hydrogel with DNA coated colloids (DNAcc), where structure formation can be triggered independently at different points in time. Consequently, we are able to create hybrid gels that are composed of the same components, but do differ in explicit colloidal structure. While monodisperse colloids enhance the storage modulus of the gels, the yield strain is simultaneously drastically reduced. The toughness of these brittle hybrid gels is rescued by colloidal structure formation at higher polyacrylamide concentrations. The toughness is increased at lower polyacrylamide concentrations. We show that the toughness of the hydrogels at 10% (w/v) polyacrylamide and 4% (v/v) DNAcc can be increased by a factor of approx. 35, indicating that control over colloidal structure formation yields access to significant synergetic effects in polymer-colloid hybrid gels.

Shear-responsive injectable supramolecular hydrogel releasing doxorubicin loaded micelles with pH-sensitivity for local tumor chemotherapy

In this study, glycol chitosan-Pluronic F127 conjugate (GC-PF127), produced by an amidation reaction between terminal-carboxylated PF127 and glycol chitosan (GC), was used to prepare doxorubicin (DOX)-loaded micelles. The DOX/GC-PF127 micelles produced at optimal conditions had sizes of about 150nm and pH-sensitive surface charges. DOX/GC-PF127 hydrogel formed after addition of α-cyclodextrin into DOX/GC-PF127 micelle solution. The hydrogel had good shear-responsive, injectable and rapid recovery properties. In vitro release experiment confirmed that the hydrogel could sustainedly release DOX/GC-PF127 micelles via the dissociation of the hydrogel. After peritumoral injection into H22 tumor-bearing mice, the hydrogel could greatly increase DOX accumulation in tumor tissue and synchronously avoid DOX accumulation in normal tissues including heart. At similar total DOX dose administrated, the tumors of free DOX treatment group grew slowly after thrice intravenous injections, the tumors of the micelle group did not grow after twice intravenous injections, and the tumors of the hydrogel group disappeared almost after once peritumoral injection. This study demonstrates that injectable DOX/GC-PF127 hydrogel, which can sustainedly release DOX-loaded micelles with tumor-targeting function, is a promising system for local tumor chemotherapy.

EGFR and CD44 Dual-Targeted Multifunctional Hyaluronic Acid Nanogels Boost Protein Delivery to Ovarian and Breast Cancers In Vitro and In Vivo

Protein drugs with intracellular targets like Granzyme B (GrB) have demonstrated great proliferative inhibition activity in cancer cells. Their clinical translation, however, relies on the development of safe, efficient, and selective protein-delivery vehicles. Here, we report that epidermal growth factor receptor (EGFR) and CD44 dual-targeted multifunctional hyaluronic acid nanogels (EGFR/CD44-NGs) boost protein delivery to ovarian and breast cancers in vitro and in vivo. EGFR/CD44-NGs obtained via nanoprecipitation and photoclick chemistry from hyaluronic acid derivatives with tetrazole, GE11 peptide/tetrazole, and cystamine methacrylate groups had nearly quantitative loading of therapeutic proteins like cytochrome C (CC) and GrB, a small size of ca. 165 nm, excellent stability in serum, and fast protein release under a reductive condition. Flow cytometry assays showed that EGFR/CD44-NGs exhibited over 6-fold better uptake in CD44 and EGFR-positive SKOV-3 ovarian cancer cells than CD44-NGs. In accordance, GrB-loaded EGFR/CD44-NGs (GrB-EGFR/CD44-NGs) displayed enhanced caspase activity and growth inhibition in SKOV-3 cells as compared to GrB-loaded CD44-NGs (GrB-CD44-NGs) control. Intriguingly, the therapeutic studies in SKOV-3 human ovarian carcinoma and MDA-MB-231 human breast tumor xenografted in nude mice revealed that GrB-EGFR/CD44-NGs at a low dose of 3.85 nmol GrB equiv/kg induced nearly complete growth suppression of both tumors, which was obviously more effective than GrB-CD44-NGs, without causing any adverse effects. EGFR and CD44 dual-targeted multifunctional hyaluronic acid nanogels have appeared as a safe and efficacious platform for cancer protein therapy.

The cornucopia of meaningful leads: Applying deep adversarial autoencoders for new molecule development in oncology

Recent advances in deep learning and specifically in generative adversarial networks have demonstrated surprising results in generating new images and videos upon request even using natural language as input. In this paper we present the first application of generative adversarial autoencoders (AAE) for generating novel molecular fingerprints with a defined set of parameters. We developed a 7-layer AAE architecture with the latent middle layer serving as a discriminator. As an input and output the AAE uses a vector of binary fingerprints and concentration of the molecule. In the latent layer we also introduced a neuron responsible for growth inhibition percentage, which when negative indicates the reduction in the number of tumor cells after the treatment. To train the AAE we used the NCI-60 cell line assay data for 6252 compounds profiled on MCF-7 cell line. The output of the AAE was used to screen 72 million compounds in PubChem and select candidate molecules with potential anti-cancer properties. This approach is a proof of concept of an artificially-intelligent drug discovery engine, where AAEs are used to generate new molecular fingerprints with the desired molecular properties.

Synthesis and evaluation of L-arabinose-based cationic glycolipids as effective vectors for pDNA and siRNA in vitro

Glycolipids might become a new type of promising non-viral gene delivery systems because of their low cytotoxicity, structural diversity, controllable aqua- and lipo-solubility, appropriate density and distribution of positive charges, high transfer efficiency and potential targeting function. In this study, four kinds of L-arabinose-based cationic glycolipids (Ara-DiC12MA, Ara-DiC14MA, Ara-DiC16MA and Ara-DiC18MA) containing quaternary ammonium as hydrophilic headgroup and two alkane chains as hydrophobic domain were synthesized and characterized. They were observed to have strong affinities for plasmid DNA (pDNA) and siRNA, the pDNA can be completely condensed at N/P ratio less than 2, and the siRNA can be completely retarded at N/P ratio less than 3. The dynamic light scattering (DLS) experiment and atomic force microscopy (AFM) experiment demonstrated that cationic lipids and their lipoplexes possessed suitable particle sizes with near-spherical shape and proper ζ-potentials for cell transfection. The Ara-DiC16MA liposome was found to have good transfection efficacy in HEK293, PC-3 and Mat cells compared with other three kinds of liposomes, and also maintain low cytotoxicity and better uptake capability in vitro. Furthermore, the gene silencing assay showed that Ara-DiC14MA and Ara-DiC16MA liposomes have demonstrated effective delivery and higher gene knockdown activity (>80%) in the above mentioned cells than Lipofectamine 2000. These results indicated Ara-DiC16MA can be developed for efficient and low toxic gene delivery.

Induction of Chondrogenic Differentiation of Human Mesenchymal Stem Cells by Biomimetic Gold Nanoparticles with Tunable RGD Density

Nanostructured materials have drawn a broad attention for their applications in biomedical fields. Ligand-modified nanomaterials can well mimic the dynamic extracellular matrix (ECM) microenvironments to regulate cell functions and fates. Herein, ECM mimetic gold nanoparticles (Au NPs) with tunable surface arginine-glycine-aspartate (RGD) density are designed and synthesized to induce the chondrogenic differentiation of human mesenchymal stem cells (hMSCs). The biomimetic Au NPs with an average size of 40 nm shows good biocompatibility without affecting the cell proliferation in the studied concentration range. The RGD motifs on Au NPs surface facilitate cellular uptake of NPs into monolayer hMSCs through integrin-mediated endocytosis. The biomimetic NPs have a promotive effect on cartilaginous matrix production and marker gene expression in cell pellet culture, especially for the biomimetic Au NPs with high surface RGD density. This study provides a novel strategy for fabricating biomimetic NPs to regulate cell differentiation, which holds great potentials in tissue engineering and biomedical applications.

pH-Switchability and Second-Order Nonlinear Optical Properties of Monocyclopentadienylruthenium(II)/iron(II) Tetrazoles/Tetrazolates: Synthesis, Characterization, and Time-Dependent Density Functional Theory Calculations

Tetrazole/tetrazolate monocyclopentadienyliron(II) and ruthenium(II) compounds of general formulas [(η⁵-C₅H₅)M(dppe)(N₄(H)CC₆H₄NO₂)][PF₆]/[(η⁵-C₅H₅)M(dppe)(N₄CC₆H₄NO₂)] were investigated for their pH-switching second-order nonlinear optical (SONLO) properties. Compounds [(η⁵-C₅H₅)M(dppe)(N₄CC₆H₄NO₂)] (M = Fe, Ru) and compound [(η⁵-C₅H₅)Ru(dppe)(N₄(H)CC₆H₄NO₂)][PF₆] were fully characterized by (¹H-, ¹³C-, ³¹P-) NMR, cyclic voltammetry, and elemental analysis, and compounds [(η⁵-C₅H₅)Fe(dppe)(N₄CC₆H₄NO₂)] and [(η⁵-C₅H₅)Ru(dppe)(N₄(H)CC₆H₄NO₂)][PF₆] were further characterized by single-crystal X-ray diffraction; the synthesis of [(η⁵-C₅H₅)Fe(dppe)(N₄(H)CC₆H₄NO₂)][PF₆] was unsuccessful. Time-dependent density functional theory calculations were performed using PBE0 and CAM-B3LYP functionals to evaluate the first hyperpolarizability (β_tot) of the tetrazole/tetrazolate complexes and for a detailed analysis of the experimental data. Both functionals predict (i) high first hyperpolarizabilities for the tetrazolate complexes [(η⁵-C₅H₅)M(dppe)(N₄CC₆H₄NO₂)], with β_tot[Ru] ≈ 1.2β_tot[Fe], and (ii) a 3-fold reduction in β_tot[Ru] upon protonation, in complex [(η⁵-C₅H₅)Ru(dppe)(N₄(H)CC₆H₄NO₂)]⁺, forecasting [(η⁵-C₅H₅)Ru(dppe)(N₄CC₆H₄NO₂)]/[(η⁵-C₅H₅)Ru(dppe)(N₄(H)CC₆H₄NO₂)]⁺ complexes as on/off, pH-switchable SONLO forms.

Functionalized Textile Based Therapy for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic inflammatory skin condition characterized by intense puritus and skin dryness. The pathogenesis for AD has not been fully understood to date. Complementary therapies are very popular as effective treatment for AD among clinical practitioners. This study presents a comprehensive review of published works associated with textiles-based complementary therapies for AD treatment such as wet-wrap dressing, functionalized textiles, and the application of hydrogel techniques in the textile industry to provide a better understanding of the development and design of new textiles-based transdermal therapies.

Chitosan based nanogels stepwise response to intracellular delivery kinetics for enhanced delivery of doxorubicin

Chitosan based nanogels with pH/redox sensitivities tunable to stepwise response to intracellular delivery kinetics were developed. The nanogels were simply constructed by ionic gelation first, between O-Carboxymethyl-chitosan (CMCS) and thiolated chitosan (TCS), and then oxidation to form disulfide bonds for CMCS-TCS nanogels (CTNGs). Doxorubicin loaded nanogels (DOX/CTNGs) exhibited desirable stability under physiological pH with a mean size of 150.5nm, and quickly aggregated at pH 5.5 (mimic endo/lysosomes) due to protonation of the carboxyl groups on CMCS. DOX/CTNGs would maintain their TCS skeleton in acidic pH and compromised as treated with 10mM glutathione (mimic cytosol). In agreement with the structural variation, release of DOX was dramatically enhanced by the synergetic effects of acidic pH and reductive potential. Stepwise responses to intracellular delivery kinetics were evidenced by laser confocal images showing that DOX/CTNGs underwent efficient cellular internalization through endocytosis, endo/lysomse escape via self-precipitation, cleavage of disulfide linkage in cytosol and disintegration in nucleus, achieving enhanced nuclear delivery and rapid release of doxorubicin. DOX/CTNGs exerted comparable or higher anticancer efficacies than that of free DOX against hela cells. The simple construction of the nanogels and their capacity of enhancing anticancer activities of DOX are potential for translational applications in cancer chemotherapy.

Biocompatible Chitosan-Carbon Dot Hybrid Nanogels for NIR-Imaging-Guided Synergistic Photothermal-Chemo Therapy

Multifunctional nanocarriers with good biocompatibility, good imaging function, and smart drug delivery ability are crucial for realizing highly efficient imaging-guided chemotherapy in vivo. This paper reports a type of chitosan-carbon dot (CD) hybrid nanogels (CCHNs, ∼65 nm) by integrating pH-sensitive chitosan and fluorescent CDs into a single nanostructure for simultaneous near-infrared (NIR) imaging and NIR/pH dual-responsive drug release to improve therapeutic efficacy. Such CCHNs were synthesized via a nonsolvent-induced colloidal nanoparticle formation of chitosan-CD complexes assisted by ethylenediaminetetraacetic acid (EDTA) molecules in the aqueous phase. The selective cross-linking of chitosan chains in the nanoparticles can immobilize small CDs complexed in the chitosan networks. The resultant CCHNs display high colloidal stability, high loading capacity for doxorubicin (DOX), bright and stable fluorescence from UV to NIR wavelength range, efficient NIR photothermal conversion, and intelligent drug release in response to both NIR light and change in pH. The results from in vitro tests on cell model and in vivo tests on different tissues of animal model indicate that the CCHNs are nontoxic. The DOX-loaded CCHNs can permeate into the implanted tumor on mice and release drug molecules efficiently on site to inhibit tumor growth. The additional photothermal treatments from NIR irradiation can further inhibit the tumor growth, benefited from the effective NIR photothermal conversion of CCHNs. The demonstrated CCHNs manifest a great promise toward multifunctional intelligent nanoplatform for highly efficient imaging-guided cancer therapy with low side effects.

Monitoring of nanoclay-protein adsorption isotherms via fluorescence techniques

The investigation of nanoparticles and their interaction with bio-macromolecules have become an important issue; the widely discussed protein corona around nanoparticles and their biological fate in general have drawn particular attention. Here, we focus on nanoclay dispersions and the use of solvatochromic fluorescent dyes (Dansyl and Coumarin 153) for monitoring the interaction with two model proteins, bovine serum albumin and β-lactoglobulin. On one hand, these dyes are poorly emissive in water, but experience a boost in their fluorescence when adsorbed into the hydrophobic domains of proteins. On the other hand, (nano)clays and clay minerals have previously been investigated in terms of their individual protein adsorption isotherms and their usefulness for the solubilization of water-insoluble dyes into an aqueous environment. In the following, we have combined all three individual parts (nanoclay, fluorophore and protein) in dispersions in a wide range of concentration ratios to systematically study the various adsorption processes via fluorescence techniques. In order to clarify the extent of dye diffusion and adsorption-desorption equilibria in the investigations, nanoclay hybrids with an adsorbed dye (Coumarin 153) and a covalently conjugated dye (Dansyl) were compared. The results suggest that the fluorescence progression of protein titration curves correlate with the amount of protein adsorbed, matching their reported adsorption isotherms on hectorite clays. Furthermore, experimental data on the protein monolayer formation around the nanoclays could be extracted due to only minor alterations of the dispersions' optical quality and transparency. In this manner, a fluorescence-based monitor for the formation of the globular protein layer around the nanoclay was realized.