A di-electrophoretic simulation procedure of iron-oxide micro-particle drug attachment system for leukemia treatment using COMSOL software: a potential treatment reference for LMICs

Background

Leukemia encompasses various subtypes, each with unique characteristics and treatment approaches. The challenge lies in developing targeted therapies that can effectively address the specific genetic mutations or abnormalities associated with each subtype. Some leukemia cases may become resistant to existing treatments over time making them less susceptible to chemotherapy or other standard therapies.

Objective

Developing new treatment strategies to overcome resistance is an ongoing challenge particularly in Low and Middle Income Countries (LMICs). Computational studies using COMSOL software could provide an economical, fast and resourceful approach to the treatment of complicated cancers like leukemia.

Methods

Using COMSOL Multiphysics software, a continuous flow microfluidic device capable of delivering anti-leukemia drugs to early-stage leukemia cells has been computationally modeled using dielectrophoresis (DEP).

Results

The cell size difference enabled the micro-particle drug attachment to the leukemia cells using hydrodynamic focusing from the dielectrophoretic force. This point of care application produced a low voltage from numerically calculated electrical field and flow speed simulations.

Conclusion

Therefore, such a dielectrophoretic low voltage application model can be used as a computational treatment reference for early-stage leukemia cells with an approximate size of 5 μm.

Controlled Bioactive Delivery Using Degradable Electroactive Polymers

Biomaterials capable of precisely controlling the delivery of agrochemicals/biologics/drugs/fragrances have significant markets in the agriscience/healthcare industries. Here, we report the development of degradable electroactive polymers and their application for the controlled delivery of a clinically relevant drug (the anti-inflammatory dexamethasone phosphate, DMP). Electroactive copolymers composed of blocks of polycaprolactone (PCL) and naturally occurring electroactive pyrrole oligomers (e.g., bilirubin, biliverdin, and hemin) were prepared and solution-processed to produce films (optionally doped with DMP). A combination of in silico/in vitro/in vivo studies demonstrated the cytocompatibility of the polymers. The release of DMP in response to the application of an electrical stimulus was observed to be enhanced by ca. 10–30% relative to the passive release from nonstimulated samples in vitro. Such stimuli-responsive biomaterials have the potential for integration devices capable of delivering a variety of molecules for technical/medical applications.

Metallosupramolecular polymers formed with silver(i) ions in aqueous solution

Supramolecular polymers of a terpyridine-based ligand (L) at three different concentrations of AgNO3 (0, 0.5, and 1.0 equiv.).

Linear and star-shaped π-conjugated oligoanilines: a review on molecular design in syntheses and properties

Molecular Design and Synthesis of Linear and Star-shaped π-conjugated Oligoanilines with reversible optoelectrochemical properties.

Electroactive peptide-based supramolecular polymers

The electroactivity as a supramolecular feature of intelligently designed self-assembled systems stimulates a wide interest in development of new stimuli-responsive biomaterials. A diverse set of nanostructures are fabricated through programmed self-assembly of molecules for functional materials. Electroactive groups are conjugated as a functional moiety for organic semiconductor applications. In this review, we present recent examples of self-assembling peptide molecules and electroactive units for supramolecular functional electronic ​and optical materials with potential biomedical and bioelectronics applications.

Exciplex emissive supramolecular polymer formed by tuning molecular conformation

We demonstrated the exciplex emission of supramolecular polymers (Bipy-1) possessing bipyridine and pyrene moieties. The distinctive exciplex emission of the supramolecular polymers was controlled by tuning the molecular conformation in different composition ratios of a mixed DMSO/H2O solution. The strong exciplex emission of the supramolecular polymer I with yellow emission was a consequence of the intramolecular charge-transfer interactions in a mixed DMSO/H2O (60 : 40-1 : 99 v/v) solution.

In situ self-assembly of conjugated polyelectrolytes for cancer targeted imaging and photodynamic therapy

The construction of intelligent self-assembly systems with cancer targeting photodynamic therapy abilities is highly required for increasing the precise therapeutic efficiency in clinical treatment. Herein, a cationic water soluble conjugated polymer (PFT-SH) functionalized with thiol groups was designed and synthesized via a palladium-catalyzed Suzuki coupling reaction. Firstly, PFT-SH can enter cells and form loose aggregations by hydrophobic and π-π stacking interactions. Secondly, a high level of H₂O₂ in cancer cells oxidizes sulfhydryl groups to disulfide bonds and then forms more and larger aggregations. Finally, PFT-SH showed remarkable ROS producing ability under white light irradiation with 78% quantum yields (Φ_Δ). Due to this unique self-aggregation property, PFT-SH was successfully used to achieve in situ self-assembly specifically inside cancer cells for targeted imaging. Both the specific aggregation of PFT-SH in cancer cells and its ROS producing ability led to its use in the targeted killing of cancer cells through efficient photodynamic therapy.

Synthesis and Self-Assembly Behavior of Chlorophyll Derivatives for Ratiometric Photoacoustic Signal Optimization

Self-assembly provides researchers powerful tools for creating ordered functional structures and complex architectures. Investigation of in vivo self-assembly reveals the assembly/aggregation-induced retention (AIR) effect and enhanced targeting effect, which can be applied to promising biomedical applications by enhancing molecular accumulation in the target region. These unique bioeffects inspire the interest of researchers in construction of self-assembled nanomaterials in biological systems. Although many efforts have been achieved, the in-depth analysis of the relationship between assemblies and functions is rarely reported. Here, we focus on the relationship of chlorophyll-derivative assemblies and their photoacoustic signals and attempt to establish a method for monitoring the aggregation efficiency in vivo based on photoacoustic signals. Three arginine-rich peptide-purpurin molecules were designed and synthesized. The assembled capabilities and assembly processes of these molecules were characterized and monitored by UV, fluorescence, and CD spectra images of gradually changing polarities in mixed solvents, and the morphologies of the assemblies were observed by TEM. Furthermore, the relationship between the aggregation ratios of the molecules and the ratiometric photoacoustic signals was systemically studied. We prospect that the fundamental research in revealing objective laws will be useful for future guidance in optimizing photoacoustic detection windows and assembled molecule design.

Self-Assembly-Assisted Kinetically Controlled Papain-Catalyzed Formation of mPEG-b-Phe(Leu)x

Self-assembling peptide materials are promising next-generation materials with applications that include tissue engineering scaffolds, drug delivery, bionanomedicine, and enviro-responsive materials. Despite these advances, synthetic methods to form peptides and peptide-polymer conjugates still largely rely on solid-phase peptide synthesis (SPPS) and N-carboxyanhydride ring-opening polymerization (NCA-ROP), while green methods remain largely undeveloped. This work demonstrates a protease-catalyzed peptide synthesis (PCPS) capable of directly grafting leucine ethyl ester (Leu-OEt) from the C-terminus of a methoxy poly(ethylene glycol)-phenylalanine ethyl ester macroinitiator in a one-pot, aqueous reaction. By using the natural tendency of the growing hydrophobic peptide segment to self-assemble, a large narrowing of the (Leu)_x distributions for both mPEG₄₅-b-Phe(Leu)_x and oligo(Leu)_x coproducts, relative to oligo(Leu)_x synthesized in the absence of a macroinitiator (mPEG₄₅-Phe-OEt), was achieved. A mechanism is described where in situ β-sheet coassembly of mPEG₄₅-b-Phe(Leu)_x and oligo(Leu)_x coproducts during polymerization prevents peptide hydrolysis, providing a means to control the degree of polymerization (DP) and dispersity of diblock (Leu)_x segments (matrix-assisted laser desorption time-of-flight (MALDI-TOF) x = 5.1, dispersity ≤ 1.02). The use of self-assembly to control the uniformity of peptides synthesized by PCPS paves the way for precise peptide block copolymer architectures with various polymer backbones and amino acid compositions synthesized by a green process.

Construction of a graphene/polypyrrole composite electrode as an electrochemically controlled release system

A biocompatible conductive composite electrode GN–PPy–FL can realize controlled release of a drug model triggered by low voltages.

Novel Riboflavin-Inspired Conjugated Bio-Organic Semiconductors

Flavins are known to be extremely versatile, thus enabling routes to innumerable modifications in order to obtain desired properties. Thus, in the present paper, the group of bio-inspired conjugated materials based on the alloxazine core is synthetized using two efficient novel synthetic approaches providing relatively high reaction yields. The comprehensive characterization of the materials, in order to evaluate the properties and application potential, has shown that the modification of the initial alloxazine core with aromatic substituents allows fine tuning of the optical bandgap, position of electronic orbitals, absorption and emission properties. Interestingly, the compounds possess multichromophoric behavior, which is assumed to be the results of an intramolecular proton transfer.

Electrochemically Enhanced Drug Delivery Using Polypyrrole Films

The delivery of drugs in a controllable fashion is a topic of intense research activity in both academia and industry because of its impact in healthcare. Implantable electronic interfaces for the body have great potential for positive economic, health, and societal impacts; however, the implantation of such interfaces results in inflammatory responses due to a mechanical mismatch between the inorganic substrate and soft tissue, and also results in the potential for microbial infection during complex surgical procedures. Here, we report the use of conducting polypyrrole (PPY)-based coatings loaded with clinically relevant drugs (either an anti-inflammatory, dexamethasone phosphate (DMP), or an antibiotic, meropenem (MER)). The films were characterized and were shown to enhance the delivery of the drugs upon the application of an electrochemical stimulus in vitro, by circa (ca.) 10⁻30% relative to the passive release from non-stimulated samples. Interestingly, the loading and release of the drugs was correlated with the physical descriptors of the drugs. In the long term, such materials have the potential for application to the surfaces of medical devices to diminish adverse reactions to their implantation in vivo.

Injectable antibacterial conductive hydrogels with dual response to an electric field and pH for localized "smart" drug release

Injectable hydrogels with multistimuli responsiveness to electrical field and pH as a drug delivery system have been rarely reported. Herein, we developed a series of injectable conductive hydrogels as "smart" drug carrier with the properties of electro-responsiveness, pH-sensitivity, and inherent antibacterial activity. The hydrogels were prepared by mixing chitosan-graft-polyaniline (CP) copolymer and oxidized dextran (OD) as a cross-linker. The chemical structures, morphologies, electrochemical property, swelling ratio, conductivity, rheological property, in vitro and in vivo biodegradation, and gelation time of hydrogels were characterized. The pH-responsive behavior was verified by drug release from hydrogels in PBS solutions with different pH values (pH = 7.4 or 5.5) in an in vitro model. As drug carriers with electric-driven release, the release rate of the model drugs amoxicillin and ibuprofen loaded within CP/OD hydrogels dramatically increased when an increase in voltage was applied. Both chitosan and polyaniline with inherent antibacterial properties endowed the hydrogels with excellent antibacterial properties. Furthermore, cytotoxicity tests of the hydrogels using L929 cells confirmed their good cytocompatibility. The in vivo biocompatibility of the hydrogels was verified by H&E staining. Together, all these results suggest that these injectable pH-sensitive conductive hydrogels with antibacterial activity could be ideal candidates as smart drug delivery vehicles for precise doses of medicine to meet practical demand.

STATEMENT OF SIGNIFICANCE

Stimuli-responsive or "smart" hydrogels have attracted great attention in the field of biotechnology and biomedicine, especially on designing novel drug delivery systems. Compared with traditional implantable electronic delivery devices, the injectable hydrogels with electrical stimuli not only are easy to generate and control electrical field but also could avoid frequent invasive surgeries that offer a new avenue for chronic diseases. In addition, designing a drug carrier with pH-sensitive property could release drug efficiently in targeted acid environment, and it could reinforce the precise doses of medicine. Furthermore, caused by opportunistic microorganisms and rapid spread of antibiotic-resistant microbes, infection is still a serious threat for many clinical utilities. To overcome these barriers, we designed a series of injectable antibacterial conductive hydrogels based on chitosan-graft-polyaniline (CP) copolymer and oxidized dextran (OD), and we demonstrated their potential as "smart" delivery vehicles with electro-responsiveness and pH-responsive properties for triggered and localized release of drugs.

Electroactive biomaterials: Vehicles for controlled delivery of therapeutic agents for drug delivery and tissue regeneration

Electrical stimulation for delivery of biochemical agents such as genes, proteins and RNA molecules amongst others, holds great potential for controlled therapeutic delivery and in promoting tissue regeneration. Electroactive biomaterials have the capability of delivering these agents in a localized, controlled, responsive and efficient manner. These systems have also been combined for the delivery of both physical and biochemical cues and can be programmed to achieve enhanced effects on healing by establishing control over the microenvironment. This review focuses on current state-of-the-art research in electroactive-based materials towards the delivery of drugs and other therapeutic signalling agents for wound care treatment. Future directions and current challenges for developing effective electroactive approach based therapies for wound care are discussed.

Gemcitabine Integrated Nano-Prodrug Carrier System

Peptide nanomaterials have received a great deal of interest in drug-delivery applications due to their biodegradability, biocompatibility, suitability for large-scale synthesis, high drug-loading capacities, targeting ability, and ordered structural organization. The covalent conjugation of drugs to peptide backbones results in prolonged circulation time and improved stability of drugs. Therapeutic efficacy of gemcitabine, which is used for breast cancer treatment, is severely compromised due to its rapid plasma degradation. Its hydrophilic nature poses a challenge for both its efficient encapsulation into nanocarrier systems and its sustained release property. Here, we designed a new peptide prodrug molecule for the anticancer drug gemcitabine, which was covalently conjugated to the C-terminal of 9-fluorenylmethoxy carbonyl (Fmoc)-protected glycine. The prodrug was further integrated into peptide nanocarrier system through noncovalent interactions. A pair of oppositely charged amyloid-inspired peptides (Fmoc-AIPs) were exploited as components of the drug-carrier system and self-assembled into one-dimensional nanofibers at physiological conditions. The gemcitabine integrated nanoprodrug carrier system exhibited slow release and reduced the cellular viability of 4T1 breast cancer cell line in a time- and concentration-dependent manner.

Synthesis and characterization of conductive, biodegradable, elastomeric polyurethanes for biomedical applications

Biodegradable conductive polymers are currently of significant interest in tissue repair and regeneration, drug delivery, and bioelectronics. However, biodegradable materials exhibiting both conductive and elastic properties have rarely been reported to date. To that end, an electrically conductive polyurethane (CPU) was synthesized from polycaprolactone diol, hexadiisocyanate, and aniline trimer and subsequently doped with (1S)-(+)-10-camphorsulfonic acid (CSA). All CPU films showed good elasticity within a 30% strain range. The electrical conductivity of the CPU films, as enhanced with increasing amounts of CSA, ranged from 2.7 ± 0.9 × 10(-10) to 4.4 ± 0.6 × 10(-7) S/cm in a dry state and 4.2 ± 0.5 × 10(-8) to 7.3 ± 1.5 × 10(-5) S/cm in a wet state. The redox peaks of a CPU1.5 film (molar ratio CSA:aniline trimer = 1.5:1) in the cyclic voltammogram confirmed the desired good electroactivity. The doped CPU film exhibited good electrical stability (87% of initial conductivity after 150 hours charge) as measured in a cell culture medium. The degradation rates of CPU films increased with increasing CSA content in both phosphate-buffered solution (PBS) and lipase/PBS solutions. After 7 days of enzymatic degradation, the conductivity of all CSA-doped CPU films had decreased to that of the undoped CPU film. Mouse 3T3 fibroblasts proliferated and spread on all CPU films. This developed biodegradable CPU with good elasticity, electrical stability, and biocompatibility may find potential applications in tissue engineering, smart drug release, and electronics. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2305-2314, 2016.

Design, fabrication, and in vitro testing of novel three-dimensionally printed tympanic membrane grafts

The tympanic membrane (TM) is an exquisite structure that captures and transmits sound from the environment to the ossicular chain of the middle ear. The creation of TM grafts by multi-material three-dimensional (3D) printing may overcome limitations of current graft materials, e.g. temporalis muscle fascia, used for surgical reconstruction of the TM. TM graft scaffolds with either 8 or 16 circumferential and radial filament arrangements were fabricated by 3D printing of polydimethylsiloxane (PDMS), flex-polyactic acid (PLA) and polycaprolactone (PCL) materials followed by uniform infilling with a fibrin-collagen composite hydrogel. Digital opto-electronic holography (DOEH) and laser Doppler vibrometry (LDV) were used to measure acoustic properties including surface motions and velocity of TM grafts in response to sound. Mechanical properties were determined using dynamic mechanical analysis (DMA). Results were compared to fresh cadaveric human TMs and cadaveric temporalis fascia. Similar to the human TM, TM grafts exhibit simple surface motion patterns at lower frequencies (400 Hz), with a limited number of displacement maxima. At higher frequencies (>1000 Hz), their displacement patterns are highly organized with multiple areas of maximal displacement separated by regions of minimal displacement. By contrast, temporalis fascia exhibited asymmetric and less regular holographic patterns. Velocity across frequency sweeps (0.2-10 kHz) measured by LDV demonstrated consistent results for 3D printed grafts, while velocity for human fascia varied greatly between specimens. TM composite grafts of different scaffold print materials and varied filament count (8 or 16) displayed minimal, but measurable differences in DOEH and LDV at tested frequencies. TM graft mechanical load increased with higher filament count and is resilient over time, which differs from temporalis fascia, which loses over 70% of its load bearing properties during mechanical testing. This study demonstrates the design, fabrication and preliminary in vitro acoustic and mechanical evaluation of 3D printed TM grafts. Data illustrate the feasibility of creating TM grafts with acoustic properties that reflect sound induced motion patterns of the human TM; furthermore, 3D printed grafts have mechanical properties that demonstrate increased resistance to deformation compared to temporalis fascia.

Synthesis and application of a novel poly-l-phenylalanine electroactive macromonomer as matrix for the biosensing of ‘Abused Drug’ model

The synthesis and biosensing application of a novel poly-l-phenylalanine-bearing electroactive macromonomer has been carried out.

Small molecular nanomedicines made from a camptothecin dimer containing a disulfide bond

Small molecules camptothecin (CPT) dimer could self-assemble into stable nanoparticles in aqueous solution, which indicated high cellular proliferation inhibition toward HeLa and HepG2 cells.