Sticky "delivering-from" strategies using viral vectors for efficient human neural stem cell infection by bioinspired catecholamines

Facile Fabrication of Three-Dimensional Hydrogel Film with Complex Tissue Morphology

In this study, we proposed a simple and easy method for fabricating a three-dimensional (3D) structure that can recapitulate the morphology of a tissue surface and deliver biological molecules into complex-shaped target tissues. To fabricate the 3D hydrogel film structure, we utilized a direct tissue casting method that can recapitulate tissue structure in micro-/macroscale using polydimethylsiloxane (PDMS). A replica 3D negative mold was manufactured by a polyurethane acrylate (PUA)-based master mold. Then, we poured the catechol-conjugated alginate (ALG-C) solution into the mold and evaporated it to form a dried film, followed by crosslinking the film using calcium chloride. The ALG-C hydrogel film had a tensile modulus of 725.2 ± 123.4 kPa and maintained over 95% of initial weight after 1 week without significant degradation. The ALG-C film captured over 4.5 times as much macromolecule (FITC-dextran) compared to alginate film (ALG). The cardiomyoblast cells exhibited high cell viability over 95% on ALG-C film. Moreover, the ALG-C film had about 70% of surface-bound lentivirus (1% in ALG film), which finally exhibited much higher viral transfection efficiency of GFP protein to C2C12 cells on the film than ALG film. In conclusion, we demonstrated a 3D film structure of biofunctionalized hydrogel for substrate-mediated drug delivery, and this approach could be utilized to recapitulate the complex-shaped tissues.

Polyphenol scaffolds in tissue engineering

Polyphenols are a class of ubiquitous compounds distributed in nature, with fascinating inherent biocompatible, bioadhesive, antioxidant, and antibacterial properties. The unique polyphenolic structures based on catechol or pyrogallol moieties allow for strong non-covalent interactions (e.g., multiple hydrogen bonding, electrostatic, and cation-π interactions) as well as covalent interactions (e.g., Michael addition/Schiff-base reaction, radical coupling reaction, and dynamic coordination interactions with boronate or metal ions). This review article provides an overview of the polyphenol-based scaffolds including the hydrogels, films, and nanofibers that have emerged from chemical and functional signatures during the past years. A full description of the structure-function relationships in terms of their utilization in wound healing, bone regeneration, and electroactive tissue engineering is also carefully discussed, which may pave the path towards the rational design and facile preparation of next-generation polyphenol scaffolds for tissue engineering applications.

Materials promoting viral gene delivery

Therapeutic viral gene delivery is an emerging technology which aims to correct genetic mutations by introducing new genetic information to cells either to correct a faulty gene or to initiate cell death in oncolytic treatments. In recent years, significant scientific progress has led to several clinical trials resulting in the approval of gene therapies for human treatment. However, successful therapies remain limited due to a number of challenges such as inefficient cell uptake, low transduction efficiency (TE), limited tropism, liver toxicity and immune response. To adress these issues and increase the number of available therapies, additives from a broad range of materials like polymers, peptides, lipids, nanoparticles, and small molecules have been applied so far. The scope of this review is to highlight these selected delivery systems from a materials perspective.

Polydopamine and Its Derivative Surface Chemistry in Material Science: A Focused Review for Studies at KAIST

Polydopamine coating, the first material-independent surface chemistry, and its related methods significantly influence virtually all areas of material science and engineering. Functionalized surfaces of metal oxides, synthetic polymers, noble metals, and carbon materials by polydopamine and its related derivatives exhibit a variety of properties for cell culture, microfluidics, energy storage devices, superwettability, artificial photosynthesis, encapsulation, drug delivery, and numerous others. Unlike other articles, this review particularly focuses on the development of material science utilizing polydopamine and its derivatives coatings at the Korea Advanced Institute of Science and Technology for a decade. Herein, it is demonstrated how material-independent coating methods provide solutions for challenging problems existed in many interdisciplinary areas in bio-, energy-, and nanomaterial science by collaborations and independent research.

An automated hybrid bioelectronic system for autogenous restoration of sinus rhythm in atrial fibrillation

Because of suboptimal therapeutic strategies, restoration of sinus rhythm in symptomatic atrial fibrillation (AF) often requires in-hospital delivery of high-voltage shocks, thereby precluding ambulatory AF termination. Continuous, rapid restoration of sinus rhythm is desired given the recurring and progressive nature of AF. Here, we present an automated hybrid bioelectronic system for shock-free termination of AF that enables the heart to act as an electric current generator for autogenous restoration of sinus rhythm. We show that local, right atrial delivery of adenoassociated virus vectors encoding a light-gated depolarizing ion channel results in efficient and spatially confined transgene expression. Activation of an implanted intrathoracic light-emitting diode device allows for termination of AF by illuminating part of the atria. Combining this newly obtained antiarrhythmic effector function of the heart with the arrhythmia detector function of a machine-based cardiac rhythm monitor in the closed chest of adult rats allowed automated and rapid arrhythmia detection and termination in a safe, effective, repetitive, yet shock-free manner. These findings hold translational potential for the development of shock-free antiarrhythmic device therapy for ambulatory treatment of AF.

Bioinspired polynorepinephrine nanoparticles as an efficient vehicle for enhanced drug delivery

Biocompatible polynorepinephrine based particles with excellent biocompatibility for efficient delivery of therapeutics to cancer cells.

AAVR-Displaying Interfaces: Serotype-Independent Adeno-Associated Virus Capture and Local Delivery Systems

Interfacing gene delivery vehicles with biomaterials has the potential to play a key role in diversifying gene transfer capabilities, including localized, patterned, and controlled delivery. However, strategies for modifying biomaterials to interact with delivery vectors must be redesigned whenever new delivery vehicles and applications are explored. We have developed a vector-independent biomaterial platform capable of interacting with various adeno-associated viral (AAV) serotypes. A water-soluble, cysteine-tagged, recombinant protein version of the recently discovered multi-AAV serotype receptor (AAVR), referred to as cys-AAVR, was conjugated to maleimide-displaying polycaprolactone (PCL) materials using click chemistry. The resulting cys-AAVR-PCL system bound to a broad range of therapeutically relevant AAV serotypes, thereby providing a platform capable of modulating the delivery of all AAV serotypes. Intramuscular injection of cys-AAVR-PCL microspheres with bound AAV vectors resulted in localized and sustained gene delivery as well as reduced spread to off-target organs compared to a vector solution. This cys-AAVR-PCL system is thus an effective approach for biomaterial-based AAV gene delivery for a broad range of therapeutic applications.

Material-Independent Surface Chemistry beyond Polydopamine Coating

Various methods have been developed in surface chemistry to control interface properties of a solid material. A selection rule among surface chemistries is compatibility between a surface functionalization tool and a target material. For example, alkanethiol deposition on noble metal surfaces, widely known as the formation of a self-assembled monolayer (SAM), cannot be performed on oxide material surfaces. One must choose organosilane molecules to functionalize oxide surfaces. Thus, the surface chemistry strictly depends on the properties of the surface. Polydopamine coating is now generally accepted as the first toolbox for functionalization of virtually any material surface. Layer-by-layer (LbL) assembly is a widely used method to modify properties of versatile surfaces, including organic materials, metal oxides, and noble metals, along with polydopamine coating. On flat solid substrates, the two chemistries of polydopamine coating and LbL assembly provide similar levels of surface modifications. However, there are additional distinct features in polydopamine. First, polydopamine coating is effective for two- or three-dimensional porous materials such as metal-organic frameworks (MOFs), synthetic polyolefin membranes, and others because small-sized dopamine (MW = 153.18 u) and its oxidized oligomers are readily attached onto narrow-spaced surfaces without exhibiting steric hindrance. In contrast, polymers used in LbL assembly are slow in diffusion because of steric hindrance due to their high molecular weight. Second, it is applicable to structurally nonflat surfaces showing special wettability such as superhydrophobicity or superoleophobicity. Third, a nonconducting, insulating polydopamine layer can be converted to be a conducting layer by pyrolysis. The product after pyrolysis is a N-doped graphene-like material that is useful for graphene or carbon nanotube-containing composites. Fourth, it is a suitable method for engineering the surface properties of various composite materials. The surface properties of participating components in composite materials can be unified by polydopamine coating with a simple one-step process. Fifth, a polydopamine layer exhibits intrinsic chemical reactivity by the presence of catecholquinone moieties and catechol radical species on surfaces. Nucleophiles such as amine and thiolate spontaneously react with the functionalized layer. Applications of polydopamine coating are exponentially growing and include cell culture/patterning, microfluidics, antimicrobial surfaces, tissue engineering, drug delivery systems, photothermal therapy, immobilization of photocatalysts, Li-ion battery membranes, Li-sulfur battery cathode materials, oil/water separation, water detoxification, organocatalysts, membrane separation technologies, carbonization, and others. In this Account, we describe various polydopamine coating methods and then introduce a number of chemical derivatives of dopamine that will open further development of material-independent surface chemistry.

A biofunctionalized viral delivery patch for spatially defined transfection

Gene therapy holds the significance of correcting genetic defects. However, difficulties in the in vivo delivery to the targeted tissues and systemic delivery remain the biggest challenges to be overcome. Here, a robust system of biofunctionalized polymeric layer-mediated lentiviral delivery was designed for the site-specific spatial and temporal control of viral gene delivery. Poly glycidyl methacrylate (pGMA) modification of a substrate via initiated chemical vapor deposition (iCVD) followed by polyethyleneimine (PEI) immobilization provided the adhesion site for the lentivirus. Furthermore, the polymeric patch based gene delivery system showed a high rate of gene transduction compared to bolus treatment. Furthermore, by using mask patterning, we were able to spatially pattern the lentivirus which allowed spatially defined transfection.

Robust, Highly Visible, and Facile Bioconjugation Colloidal Crystal Beads for Bioassay

High mechanical strength, highly visible, and admirable grafting molecular ability is the key challenge for colloidal photonic crystal (CPC) barcode beads in multiplex analysis fields. To achieve this goal, we proposed self-adhesion particles, polydopamine-coated SiO₂ nanoparticles (PDA@SiO₂), to construct CPC barcode beads by droplet-based microfluidic approach. Because of the adhesion, broad absorption of light, and "active" functional groups of PDA, the beads are endowed with high robustness, visibility, and excellent biomolecule immobilization. Ultrasonic treatment and compression experiments demonstrated that PDA@SiO₂ CPC barcode beads have a high mechanical strength. Color analysis illustrated that PDA@SiO₂ CPC beads exhibited a high visibility in color. The verification of fluorescent-tagged biomolecule conjugation together with the antigen detection stated that PDA@SiO₂ CPC beads are capable of immobilizing biomolecule by covalent binding. With a sandwich format, the beads were applied to analyze the tumor makers including alpha fetal protein, carcinoembryonic antigen, and prostate specific antigen from practical clinical serum. The proposed suspension arrays using PDA@SiO₂ CPC beads as a barcode showed acceptable accuracy and detection reproducibility.

Triptorelin Tethered Multifunctional PAMAM-Histidine-PEG Nanoconstructs Enable Specific Targeting and Efficient Gene Silencing in LHRH Overexpressing Cancer Cells

Cancer treatment using siRNA based therapies pose various limitations such as off-target effects and degradation due to lack of specific delivery in desired cells. The aim of the present study was to develop multifunctional targeted nanoconstructs, which can efficiently and precisely deliver siRNA and silence the desired gene of interest in various LHRH overexpressing cancer cells. Herein, we report the development of triblock, PAMAM-histidine-PEG dendritic nanoconstructs functionalized with triptorelin (an LHRH analog) for targeted siRNA delivery to LHRH overexpressing breast (MCF-7) and prostate (LNCaP) cancer cells. The nanoconstructs were characterized using ¹H NMR and DLS and displayed a very low cationic charge to avoid off-target interactions. The developed nanoconstructs showed negligible cytotoxicity and hemolytic activity with efficient siRNA loading, excellent serum stability, and strongly protected siRNA from degradation. Further, confocal microscopy results confirmed extremely significant (p < 0.001) higher cellular uptake of cy5.5 conjugated targeted nanoparticles (NPs) in both cancer cell lines than nontargeted NPs. Also, targeted NPs specifically delivered cy3-tagged siRNA to MCF-7 cells. Co-localization studies in MCF-7 and LNCaP cells further established that targeted NPs traveled through the endolysosomal pathway and escaped endosomes within 6 h of incubation. Gene silencing studies in luciferase expressing MCF-7 and LNCaP cell lines demonstrated that the targeted NPs exhibited extremely significant (p < 0.001) silencing of luciferase gene. Additionally, receptor blockade studies further confirmed the specificity of targeted NPs and suggested that targeted NPs entered cancer cells via LHRH receptor mediated endocytosis, which was evident through insignificant gene silencing in receptor blocked cells. Thus, the results indicated that PAMAM-histidine-PEG-triptorelin could be a promising approach for siRNA delivery, gene silencing, and tumor therapy in all LHRH overexpressing cancer cells.

Biomaterial-Guided Gene Delivery for Musculoskeletal Tissue Repair

Gene therapy is a promising strategy for musculoskeletal tissue repair and regeneration where local and sustained expression of proteins and/or therapeutic nucleic acids can be achieved. However, the musculoskeletal tissues present unique engineering and biological challenges as recipients of genetic vectors. Targeting specific cell populations, regulating expression in vivo, and overcoming the harsh environment of damaged tissue accompany the general concerns of safety and efficacy common to all applications of gene therapy. In this review, we will first summarize these challenges and then discuss how biomaterial carriers for genetic vectors can address these issues. Second, we will review how limitations specific to given vectors further motivate the utility of biomaterial carriers. Finally, we will discuss how these concepts have been combined with tissue engineering strategies and approaches to improve the delivery of these vectors for musculoskeletal tissue regeneration.

Mutagenic Analysis of an Adeno-Associated Virus Variant Capable of Simultaneously Promoting Immune Resistance and Robust Gene Delivery

In addition to the ability to boost gene delivery efficiency in many therapeutically relevant cells, the capability of circumventing neutralizing antibody (NAb) inactivation is a key prerequisite that gene carriers must fulfill for their extensive applications as therapeutic agents in many gene therapy trials, especially for cancer treatments. This study revealed that a genetically engineered adeno-associated virus (AAV) variant, AAVr3.45, inherently possesses dual beneficial properties as a gene carrier: (i) efficiently delivering therapeutic genes to many clinically valuable cells (e.g., stem or cancer cells) and (ii) effectively bypassing immunoglobulin (IgG) neutralization. Detailed interpretation of the structural features of AAVr3.45, which was previously engineered from AAV2, demonstrated that the LATQVGQKTA peptide at the heparan sulfate proteoglycan binding domain, especially the presence of cationic lysine on the peptide, served as a key motif for dramatically enhancing its gene delivery capabilities, ultimately broadening its tropisms for many cancer cell lines. Furthermore, the substitution of valine on the AAV2 capsid at the amino acid 719 site to methionine functioned as a coordinator for promoting viral resistance against IgG inactivation. The NAb-resistant characteristics of AAVr3.45 were possibly associated with the LATQVGQKTA sequence itself, indicating that its synergistic cooperation with the point mutation (V719M) is required for maximizing its ability to evade NAb inactivation. The potential of AAVr3.45 as a cancer gene therapy agent was confirmed by provoking apoptosis in breast adenocarcinoma by efficiently delivering a pro-apoptotic gene, BIM (Bcl-2-like protein 11), under high titers of human IgG. Thus, the superior aspects of the NAb-resistant AAVr3.45 as a potential therapeutic agent for systemic injection approaches, especially for cancer gene therapy, were highlighted in this study.

Development of efficient adeno-associated virus (AAV)-mediated gene delivery system with a phytoactive material for targeting human melanoma cells

We exploited the emerging potential of gene therapy strategies to design a powerful therapeutic system that combines two key components-AAV vector and [6]-gingerol. In this study, we created an AAV2 construct expressing the proapoptotic protein BIM, which uses HSPG as its primary receptor, to target HSPG-overexpressing melanoma cells. This combination treatment showed promising results in vitro, inducing apoptosis in human melanoma cells. This new platform technology will make a significant contribution to numerous therapeutic applications, most notably for melanoma, including overcoming resistance to conventional anticancer therapies.

Polydopamine-Assisted Surface Modification for Bone Biosubstitutes

Polydopamine (PDA) prepared in the form of a layer of polymerized dopamine (DA) in a weak alkaline solution has been used as a versatile biomimetic surface modifier as well as a broadly used immobilizing macromolecule. This review mainly discusses the progress of biomaterial surface modification inspired by the participation of PDA in bone tissue engineering. A comparison between PDA-assisted coating techniques and traditional surface modification applied to bone tissue engineering is first presented. Secondly, the chemical composition and the underlying formation mechanism of PDA coating layer as a unique surface modifier are interpreted and discussed. Furthermore, several typical examples are provided to evidence the importance of PDA-assisted coating techniques in the construction of bone biosubstitutes and the improvement of material biocompatibility. Nowadays, the application of PDA as a superior surface modifier in multifunctional biomaterials is drawing tremendous interests in bone tissue scaffolds to promote the osteointegration for bone regeneration.

Polydopamine Inter-Fiber Networks: New Strategy for Producing Rigid, Sticky, 3D Fluffy Electrospun Fibrous Polycaprolactone Sponges

Designing versatile 3D interfaces that can precisely represent a biological environment is a prerequisite for the creation of artificial tissue structures. To this end, electrospun fibrous sponges, precisely mimicking an extracellular matrix and providing highly porous interfaces, have capabilities that can function as versatile physical cues to regenerate various tissues. However, their intrinsic features, such as sheet-like, thin, and weak structures, limit the design of a number of uses in tissue engineering applications. Herein, a highly facile methodology capable of fabricating rigid, sticky, spatially expanded fluffy electrospun fibrous sponges is proposed. A bio-inspired adhesive material, poly(dopamine) (pDA), is employed as a key mediator to provide rigidity and stickiness to the 3D poly(ε-caprolactone) (PCL) fibrous sponges, which are fabricated using a coaxial electrospinning with polystyrene followed by a selective leaching process. The iron ion induced oxidation of dopamine into pDA networks interwoven with PCL fibers results in significant increases in the rigidity of 3D fibrous sponges. Furthermore, the exposure of catecholamine groups on the fiber surfaces promotes the stable attachment of the sponges on wet organ surfaces and triggers the robust immobilization of biomolecules (e.g., proteins and gene vectors), demonstrating their potential for 3D scaffolds as well as drug delivery vehicles. Because fibrous structures are ubiquitous in the human body, these rigid, sticky, 3D fibrous sponges are good candidates for powerful biomaterial systems that functionally mimic a variety of tissue structures.

Gene delivery strategies to promote spinal cord repair

Gene therapies hold great promise for the treatment of many neurodegenerative disorders and traumatic injuries in the central nervous system. However, development of effective methods to deliver such therapies in a controlled manner to the spinal cord is a necessity for their translation to the clinic. Although essential progress has been made to improve efficiency of transgene delivery and reduce the immunogenicity of genetic vectors, there is still much work to be done to achieve clinical strategies capable of reversing neurodegeneration and mediating tissue regeneration. In particular, strategies to achieve localized, robust expression of therapeutic transgenes by target cell types, at controlled levels over defined time periods, will be necessary to fully regenerate functional spinal cord tissues. This review summarizes the progress over the last decade toward the development of effective gene therapies in the spinal cord, including identification of appropriate target genes, improvements to design of genetic vectors, advances in delivery methods, and strategies for delivery of multiple transgenes with synergistic actions. The potential of biomaterials to mediate gene delivery while simultaneously providing inductive scaffolding to facilitate tissue regeneration is also discussed.

Electrospun nanofibers as versatile interfaces for efficient gene delivery

The integration of gene delivery technologies with electrospun nanofibers is a versatile strategy to increase the potential of gene therapy as a key platform technology that can be readily utilized for numerous biomedical applications, including cancer therapy, stem cell therapy, and tissue engineering. As a spatial template for gene delivery, electrospun nanofibers possess highly advantageous characteristics, such as their ease of production, their ECM-analogue nature, the broad range of choices for materials, the feasibility of producing structures with varied physical and chemical properties, and their large surface-to-volume ratios. Thus, electrospun fiber-mediated gene delivery exhibits a great capacity to modulate the spatial and temporal release kinetics of gene vectors and enhance gene delivery efficiency. This review discusses the powerful characteristics of electrospun nanofibers, which can function as spatial interfaces capable of promoting controlled and efficient gene delivery.