Improving assay feasibility and biocompatibility of 3D cyclic olefin copolymer microwells by superhydrophilic modification via ultrasonic spray deposition of polyvinyl alcohol

Sample partitioning is a crucial step towards digitization of biological assays on polymer microfluidic platforms. However, effective liquid filling into microwells and long-term hydrophilicity remain a challenge in polymeric microfluidic devices, impeding the applicability in diagnostic and cell culture studies. To overcome this, a method to produce permanent superhydrophilic 3-dimensional microwells using cyclic olefin copolymer (COC) microfluidic chips is presented. The COC substrate is oxidized using UV treatment followed by ultrasonic spray coating of polyvinyl alcohol solution, offering uniform and long-term coating of high-aspect ratio microfeatures. The coated COC surfaces are UV-cured before bonding with a hydrophobic pressure-sensitive adhesive to drive selective filling into the wells. The surface hydrophilicity achieved using this method remains unchanged (water contact angle of 9°) for up to 6 months and the modified surface is characterized for physical (contact angle & surface energy, morphology, integrity of microfeatures and roughness), chemical composition (FTIR, Raman spectroscopy) and coating stability (pH, temperature, time). To establish the feasibility of the modified surface in biological applications, PVA-coated COC microfluidic chips are tested for DNA sensing (digital LAMP detection of CMV), and biocompatibility through protein adsorption and cell culture studies (cell adhesion, viability, and metabolic activity). Kidney and breast cells remained viable for the duration of testing (7 days) on this modified surface, and the coating did not affect the protein content, morphology or quality of the cultured cells. The ultrasonic spray coated system, coating with 0.25 % PVA for 15 cycles with 0.12 A current after UV oxidation, increased the surface energy of the COC (naturally hydrophobic) from 22.04 to 112.89 mJ/m2 and improved the filling efficiency from 40 % (native untreated COC) to 94 % in the microwells without interfering with the biocompatibility of the surface, proving to be an efficient, high-throughput and scalable method of microfluidic surface treatment for diagnostic and cell growth applications.

Synthesis, physicochemical characterization, and investigation of anti-inflammatory activity of water-soluble PEGylated 1,2,4-Triazoles

A series of water-soluble PEGylated 1,2,4-triazoles 5-8 were successfully synthesized from methyl 5-(chloromethyl)-1-aryl-1H-1,2,4-triazole-3-carboxylates 1. All of the water-soluble PEGylated 1,2,4-triazoles were characterized by FT-IR and 1H NMR spectroscopy. The solubility, in vitro plasma stability, and anti-inflammatory activity were also determined and compared to original methyl 5-(halomethyl)-1-aryl-1H-1,2,4-triazole-3-carboxylates. For SAR study, all PEGylated 1,2,4-triazoles 5-8 performed potential anti-inflammatory activity on LPS-induced RAW 264.7 cells (IC50 = 3.42-7.81 μM). Moreover, the western blot result showed PEGylated 1,2,4-triazole 7d performed 5.43 and 2.37 folds inhibitory activity over iNOS and COX-2 expressions. On the other hand, the cell viability study revealed PEGylated 1,2,4-triazoles 7 and 8 with PEG molecular weight more than 600 presented better cell safety (cell viability > 95 %). Through the solubility and in vitro plasma stability studies, PEGylated 1,2,4-triazoles 7a-d exhibited higher hydrophilicity and prolonged 2.01 folds of half-life in compound 7d. Furthermore, the in vivo anti-inflammatory and gastric safety results indicated PEGylated 1,2,4-triazole 7d more effectively decreased the inflammatory response in edema and COX-2 expression and exhibited higher gastric safety than Indomethacin. Following the in vitro and in vivo study results, PEGylated 1,2,4-triazole 7d possessed favorable solubility, plasma stability features, safety, and significant anti-inflammatory activity to become the potential water-soluble anti-inflammatory candidate.

Fabrication of fully aligned self-assembled cell-laden collagen filaments for tissue engineering via a hybrid bioprinting process

Cell-laden structures play a pivotal role in various tissue engineering applications, particularly in tissue restoration. Interactions between cells within bioprinted structures are crucial for successful tissue development and regulation of stem cell fate through intricate cell-to-cell signaling pathways. In this study, we developed a new technique that combines polyethylene glycol (PEG)-infused submerged bioprinting with a stretching procedure. This approach facilitated the generation of fully aligned collagen structures consisting of myoblasts and a low concentration (2 wt%) of collagen to efficiently encourage muscle tissue regeneration. By adjusting several processing parameters, we obtained biologically safe and mechanically stable cell-laden collagen filaments with uniaxial alignment. Notably, the cell filaments exhibited markedly elevated cellular activities compared to those exhibited by conventional bioprinted filaments, even at similar cell densities. Moreover, when we implanted structures containing adipose stem cells into mice, we observed a significantly increased level of myogenesis compared to that in normally bioprinted struts. Thus, this promising approach has the potential to revolutionize tissue engineering by fostering enhanced cellular interactions and promoting improved outcomes in regenerative medicine.

Three-Dimensional Bioprinting of GelMA Hydrogels with Culture Medium: Balancing Printability, Rheology and Cell Viability for Tissue Regeneration

Three-dimensional extrusion bioprinting technology aims to become a fundamental tool for tissue regeneration using cell-loaded hydrogels. These biomaterials must have highly specific mechanical and biological properties that allow them to generate biosimilar structures by successive layering of material while maintaining cell viability. The rheological properties of hydrogels used as bioinks are critical to their printability. Correct printability of hydrogels allows the replication of biomimetic structures, which are of great use in medicine, tissue engineering and other fields of study that require the three-dimensional replication of different tissues. When bioprinting cell-loaded hydrogels, a small amount of culture medium can be added to ensure adequate survival, which can modify the rheological properties of the hydrogels. GelMA is a hydrogel used in bioprinting, with very interesting properties and rheological parameters that have been studied and defined for its basic formulation. However, the changes that occur in its rheological parameters and therefore in its printability, when it is mixed with the culture medium necessary to house the cells inside, are unknown. Therefore, in this work, a comparative study of GelMA 100% and GelMA in the proportions 3:1 (GelMA 75%) and 1:1 (GelMA 50%) with culture medium was carried out to determine the printability of the gel (using a device of our own invention), its main rheological parameters and its toxicity after the addition of the medium and to observe whether significant differences in cell viability occur. This raises the possibility of its use in regenerative medicine using a 3D extrusion bioprinter.

In vitro and in vivo characterization of human serum albumin-based PEGylated nanoparticles for BDNF and NT3 codelivery

The utilization of neurotrophins in medicine shows significant potential for addressing neurodegenerative conditions, such as age-related macular degeneration (AMD). However, the therapeutic use of neurotrophins has been restricted due to their short half-life. Here, we aimed to synthesize PEGylated nanoparticles based on electrostatic-driven interactions between human serum albumin (HSA), a carrier for adsorption; neurotrophin-3 (NT3); and brain-derived neurotrophic factor (BDNF). Electrophoretic (ELS) and multi-angle dynamic light scattering (MADLS) revealed that the PEGylated HSA-NT3-BDNF nanoparticles ranged from 10 to 430 nm in diameter and exhibited a low polydispersity index (<0.4) and a zeta potential of -8 mV. Based on microscale thermophoresis (MST), the estimated dissociation constant (Kd) from the HSA molecule of BDNF was 1.6 μM, and the Kd of NT3 was 732 μM. The nanoparticles were nontoxic toward ARPE-19 and L-929 cells in vitro and efficiently delivered BDNF and NT3. Based on the biodistribution of neurotrophins after intravitreal injection into BALB/c mice, both nanoparticles were gradually released in the mouse vitreous body within 28 days. PEGylated HSA-NT3-BDNF nanoparticles stabilize neurotrophins and maintain this characteristic in vivo. Thus, given the simplicity of the system, the nanoparticles may enhance the treatment of a variety of neurological disorders in the future.

Effect of polyethylene glycol on polysaccharides: From molecular modification, composite matrixes, synergetic properties to embeddable application in food fields

Polyethylene glycol (PEG) is a flexible, water-soluble, non-immunogenic, as well as biocompatible polymer, and it could synergize with polysaccharides for food applications. The molecular modification strategies, including covalent bond interactions (amino groups, carboxyl groups, aldehyde groups, tosylate groups, etc.), and non-covalent bond interactions (hydrogen bonding, electrostatic interactions, etc.) on PEG molecular chains are discussed. Its versatile structure, group modifiability, and amphiphilic block buildability could improve the functions of polysaccharides (e.g., chitosan, cellulose, starch, alginate, etc.) and adjust the properties of combined PEG/polysaccharides with outstanding chain tunability and matrix processability owing to plasticizing effects, compatibilizing effects, steric stabilizing effects and excluded volume effects by PEG, for achieving the diverse performance targets. The synergetic properties of PEG/polysaccharides with remarkable architecture were summarized, including mechanical properties, antibacterial activity, antioxidant performance, self-healing properties, carrier and delivery characteristics. The PEG/polysaccharides with excellent combined properties and embeddable merits illustrate potential applications including food packaging, food intelligent indication/detection, food 3D printing and nutraceutical food absorption. Additionally, prospects (like food innovation and preferable nutrient utilization) and key challenges (like structure-effectiveness-applicability relationship) for PEG/polysaccharides are proposed and addressed for food fields.

Microfluidic Single-Cell Study on Arabidopsis thaliana Protoplast Fusion-New Insights on Timescales and Reversibilities

Plant cells are omnipotent and breeding of new varieties can be achieved by protoplast fusion. Such fusions can be achieved by treatment with poly(ethylene glycol) or by applying an electric field. Microfluidic devices allow for controlled conditions and targeted manipulation of small batches of cells down to single-cell analysis. To provide controlled conditions for protoplast fusions and achieve high reproducibility, we developed and characterized a microfluidic device to reliably trap some Arabidopsis thaliana protoplasts and induced cell fusion by controlled addition of poly(ethylene glycol) (PEG, with a molecular weight of 6000). Experiments were conducted to determine the survival rate of isolated protoplasts in our microfluidic system. Afterward, PEG-induced fusion was studied. Our results indicate that the following fusion parameters had a significant impact on the fusion efficiency and duration: PEG concentration, osmolality of solution and flow velocity. A PEG concentration below 10% led to only partial fusion. The osmolality of the PEG fusion solution was found to strongly impact the fusion process; complete fusion of two source cells sufficiently took part in slightly hyper-osmotic solutions, whereas iso-osmotic solutions led to only partial fusion at a 20% PEG concentration. We observed accelerated fusion for higher fluid velocities. Until this study, it was common sense that fusion is one-directional, i.e., once two cells are fused into one cell, they stay fused. Here, we present for the first time the reversible fusion of protoplasts. Our microfluidic device paves the way to a deeper understanding of the kinetics and processes of cell fusion.

Systemic Treatment with Fas-Blocking Peptide Attenuates Apoptosis in Brain Ischemia

Apoptosis plays a crucial role in neuronal injury, with substantial evidence implicating Fas-mediated cell death as a key factor in ischemic strokes. To address this, inhibition of Fas-signaling has emerged as a promising strategy in preventing neuronal cell death and alleviating brain ischemia. However, the challenge of overcoming the blood-brain barrier (BBB) hampers the effective delivery of therapeutic drugs to the central nervous system (CNS). In this study, we employed a 30 amino acid-long leptin peptide to facilitate BBB penetration. By conjugating the leptin peptide with a Fas-blocking peptide (FBP) using polyethylene glycol (PEG), we achieved specific accumulation in the Fas-expressing infarction region of the brain following systemic administration. Notably, administration in leptin receptor-deficient db/db mice demonstrated that leptin facilitated the delivery of FBP peptide. We found that the systemic administration of leptin-PEG-FBP effectively inhibited Fas-mediated apoptosis in the ischemic region, resulting in a significant reduction of neuronal cell death, decreased infarct volumes, and accelerated recovery. Importantly, neither leptin nor PEG-FBP influenced apoptotic signaling in brain ischemia. Here, we demonstrate that the systemic delivery of leptin-PEG-FBP presents a promising and viable strategy for treating cerebral ischemic stroke. Our approach not only highlights the therapeutic potential but also emphasizes the importance of overcoming BBB challenges to advance treatments for neurological disorders.

Biocompatible Nanocomposites for Postoperative Adhesion: A State-of-the-Art Review

To reduce and prevent postsurgical adhesions, a variety of scientific approaches have been suggested and applied. This includes the use of advanced therapies like tissue-engineered (TE) biomaterials and scaffolds. Currently, biocompatible antiadhesive constructs play a pivotal role in managing postoperative adhesions and several biopolymer-based products, namely hyaluronic acid (HA) and polyethylene glycol (PEG), are available on the market in different forms (e.g., sprays, hydrogels). TE polymeric constructs are usually associated with critical limitations like poor biocompatibility and mechanical properties. Hence, biocompatible nanocomposites have emerged as an advanced therapy for postoperative adhesion treatment, with hydrogels and electrospun nanofibers among the most utilized antiadhesive nanocomposites for in vitro and in vivo experiments. Recent studies have revealed that nanocomposites can be engineered to generate smart three-dimensional (3D) scaffolds that can respond to different stimuli, such as pH changes. Additionally, nanocomposites can act as multifunctional materials for the prevention of adhesions and bacterial infections, as well as tissue healing acceleration. Still, more research is needed to reveal the clinical potential of nanocomposite constructs and the possible success of nanocomposite-based products in the biomedical market.

An investigation into the cytotoxic effects of microbubbles and their constituents on osteosarcoma and bone marrow stromal cells

BACKGROUND

Ultrasound-responsive microbubbles offer a means of achieving minimally invasive, localised drug delivery in applications including regenerative medicine. To facilitate their use, however, it is important to determine any cytotoxic effects they or their constituents may have. The aim of this study was to test the hypothesis that phospholipid-shelled microbubbles are non-toxic to human bone-derived cells at biologically-relevant concentrations.

METHODS

Microbubbles were fabricated using combinations of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dibehenoyl-sn-glycero-3-phosphocholine (DBPC), polyoxyethylene(40) stearate (PEG40S) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene-glycol)-2000] (DSPE-PEG2000). Microbubble size and concentration were measured as a function of time and temperature by optical microscopy. Effects on MG63 osteosarcoma and human bone marrow stromal cells (BMSCs) were measured for up to 72 h by assay for viability, metabolic activity and proliferation.

RESULTS

DBPC:DSPE-PEG2000 microbubbles were significantly more stable than DSPC:PEG40S microbubbles under all conditions tested. Serum-containing medium had no detrimental effect on microbubble stability, but storage at 37 °C compared to at 4 °C reduced stability for both preparations, with almost complete dissolution of microbubbles at times ≥24 h. DSPC:PEG40S microbubbles had greater inhibitory effects on cell metabolism and growth than DBPC:DSPE-PEG2000 microbubbles, with PEG40S found to be the principle inhibitory component. These effects were only evident at high microbubble concentrations (≥20% (v/v)) or with prolonged culture (≥24 h). Increasing cell-microbubble contact by inversion culture in a custom-built device had no inhibitory effect on metabolism.

CONCLUSIONS

These data indicate that, over a broad range of concentrations and incubation times, DBPC:DSPE-PEG2000 and DSPC:PEG40S microbubbles have little effect on osteoblastic cell viability and growth, and that PEG40S is the principle inhibitory component in the formulations investigated.

Genetically Engineered Protein-Based Bioadhesives with Programmable Material Properties

Silk-amyloid-mussel foot protein (SAM) hydrogels made from recombinant fusion proteins containing β-amyloid peptide, spider silk domain, and mussel foot protein (Mfp) are attractive bioadhesives as they display a unique combination of tunability, biocompatibility, bioabsorbability, strong cohesion, and underwater adhesion to a wide range of biological surfaces. To design tunable SAM hydrogels for tailored surgical repair applications, an understanding of the relationships between protein sequence and hydrogel properties is imperative. Here, we fabricated SAM hydrogels using fusion proteins of varying lengths of silk-amyloid repeats and Mfps to characterize their structure and properties. We found that increasing silk-amyloid repeats enhanced the hydrogel's β-sheet content (r = 0.74), leading to higher cohesive strength and toughness. Additionally, increasing the Mfp length beyond the half-length of the full Mfp sequence (1/2 Mfp) decreased the β-sheet content (r = -0.47), but increased hydrogel surface adhesion. Among different variants, the hydrogel made of 16xKLV-2Mfp displayed a high ultimate strength of 3.0 ± 0.3 MPa, an ultimate strain of 664 ± 119%, and an attractive underwater adhesivity of 416 ± 20 kPa to porcine skin. Collectively, the sequence-structure-property relationships learned from this study will be useful to guide the design of future protein adhesives with tunable characteristics for tailored surgical applications.

The explicit role of interfacial hydration during polyethylene glycol induced lipid fusion: a THz spectroscopic investigation

While the phenomenon of excipient mediated membrane fusion has been studied widely, the inherent role of interfacial hydration involved in the process has mostly remained unaddressed. Here we report the experimental validation of the fact that PEG-induced membrane fusion is associated with the dehydration of the membrane(s). We explore the explicit hydration behavior at three different lipids (DOPC, POPC and DPPC) membranes with different aliphatic tails as they undergo fusogenic transition in the presence of PEG of average molecular weight of 4000 using THz-FTIR spectroscopy in the frequency window of 1.5-13.5 THz. Dynamic light scattering and electron microscopic measurements confirm the formation of different intermediate steps of the liposomes during the fusion process: bilayer aggregation, destabilization and finally lipid fusion. We observe that membrane hydration follows a systematic trend with the lipid specificity as the fusion process sets in.

Advancing glioblastoma imaging: Exploring the potential of organic fluorophore-based red emissive carbon dots

Over time, the interest in developing stable photosensitizers (PS) which both absorb and emit light in the red region (650 and 950 nm) has gained noticeable interest. Recently, carbon dots (CDs) have become the material of focus to act as a PS due to their high extinction coefficient, low cytotoxicity, and both high photo and thermal stability. In this work, a Federal and Drug Association (FDA) approved Near Infra-Red (NIR) organic fluorophore used for photo-imaging, indocyanine green (ICG), has been explored as a precursor to develop water-soluble red emissive CDs which possess red emission at 697 nm. Furthermore, our material was found to yield favorable red-imaging capabilities of glioblastoma stem-like cells (GSCs) meanwhile boasting low toxicity. Additionally with post modifications, our CDs have been found to have selectivity towards tumors over healthy tissue as well as crossing the blood-brain barrier (BBB) in zebrafish models.

Elucidating osseointegration in vivo in 3D printed scaffolds eliciting different foreign body responses

Osseointegration between biomaterial and bone is critical for the clinical success of many orthopaedic and dental implants. However, the mechanisms of in vivo interfacial bonding formation and the role of immune cells in this process remain unclear. In this study, we investigated the bone-scaffold material interfaces in two different 3D printed porous scaffolds (polymer/hydroxyapatite and sintered hydroxyapatite) that elicited different levels of foreign body response (FBR). The polymer/hydroxyapatite composite scaffolds elicited more intensive FBR, which was evidenced by more FBR components, such as macrophages/foreign body giant cells and fibrous tissue, surrounding the material surface. Sintered hydroxyapatite scaffolds showed less intensive FBR compared to the composite scaffolds. The interfacial bonding appeared to form via new bone first forming within the pores of the scaffolds followed by growing towards strut surfaces. In contrast, it was previously thought that bone regeneration starts at biomaterial surfaces via osteogenic stem/progenitor cells first attaching to them. The material-bone interface of the less immunogenic hydroxyapatite scaffolds was heterogenous across all samples, evidenced by the coexistence of osseointegration and FBR components. The presence of FBR components appeared to inhibit osseointegration. Where FBR components were present there was no osseointegration. Our results offer new insight on the in vivo formation of bone-material interface, which highlights the importance of minimizing FBR to facilitate osseointegration for the development of better orthopaedic and dental biomaterials.

Versatile Tissue-Injectable Hydrogels with Extended Hydrolytic Release of Bioactive Protein Therapeutics

Hydrogels generally have broad utilization in healthcare due to their tunable structures, high water content, and inherent biocompatibility. FDA-approved applications of hydrogels include spinal cord regeneration, skin fillers, and local therapeutic delivery. Drawbacks exist in the clinical hydrogel space, largely pertaining to inconsistent therapeutic exposure, short-lived release windows, and difficulties inserting the polymer into tissue. In this study, we engineered injectable, biocompatible hydrogels that function as a local protein therapeutic depot with a high degree of user-customizability. We showcase a PEG-based hydrogel functionalized with bioorthogonal strain-promoted azide-alkyne cycloaddition (SPAAC) handles for its polymerization and functionalization with a variety of payloads. Small-molecule and protein cargos, including chemokines and antibodies, were site-specifically modified with hydrolysable "azidoesters" of varying hydrophobicity via direct chemical conjugation or sortase-mediated transpeptidation. These hydrolysable esters afforded extended release of payloads linked to our hydrogels beyond diffusion; with timescales spanning days to months dependent on ester hydrophobicity. Injected hydrogels polymerize in situ and remain in tissue over extended periods of time. Hydrogel-delivered protein payloads elicit biological activity after being modified with SPAAC-compatible linkers, as demonstrated by the successful recruitment of murine T-cells to a mouse melanoma model by hydrolytically released murine CXCL10. These results highlight a highly versatile, customizable hydrogel-based delivery system for local delivery of protein therapeutics with payload release profiles appropriate for a variety of clinical needs.

Off target toxicities and links with physicochemical properties of medicinal products, including antibiotics, oligonucleotides, lipid nanoparticles (with cationic and/or anionic charges). Data review suggests an emerging pattern

Toxicology is an essential part of any drug development plan. Circumnavigating the risk of failure because of a toxicity issue can be a challenge, and failure in late development is extremely costly. To identify potential risks, it requires more than just understanding the biological target. The toxicologist needs to consider a compound's structure, it's physicochemical properties (including the impact of the overall formulation), as well as the biological target (e.g., receptor interactions). Understanding the impact of the physicochemical properties can be used to predict potential toxicities in advance by incorporating key endpoints in early screening strategies and/or used to compare toxicity profiles across lead candidates. This review discussed the risks of off-target and/or non-specific toxicities that may be associated with the physicochemical properties of compounds, especially those carrying dominant positive or negative charges, including amphiphilic small molecules, peptides, oligonucleotides and lipids/liposomes/lipid nanoparticles. The latter of which are being seen more and more in drug development, including the recent Covid pandemic, where mRNA and lipid nanoparticle technology is playing more of a role in vaccine development. The translation between non-clinical and clinical data is also considered, questioning how a physicochemical driven toxicity may be more universal across species, which means that such toxicity may be reassuringly translatable between species and as such, this information may also be considered as a support to the 3 R's, particularly in the early screening stages of a drug development plan.

Targeting Peptides: The New Generation of Targeted Drug Delivery Systems

Peptides can act as targeting molecules, analogously to oligonucleotide aptamers and antibodies. They are particularly efficient in terms of production and stability in physiological environments; in recent years, they have been increasingly studied as targeting agents for several diseases, from tumors to central nervous system disorders, also thanks to the ability of some of them to cross the blood-brain barrier. In this review, we will describe the techniques employed for their experimental and in silico design, as well as their possible applications. We will also discuss advancements in their formulation and chemical modifications that make them even more stable and effective. Finally, we will discuss how their use could effectively help to overcome various physiological problems and improve existing treatments.

Smart Poly(lactide)-b-poly(triethylene glycol methyl ether methacrylate) (PLA-b-PTEGMA) Block Copolymers: One-Pot Synthesis, Temperature Behavior, and Controlled Release of Paclitaxel

This paper introduces a new class of amphiphilic block copolymers created by combining two polymers: polylactic acid (PLA), a biocompatible and biodegradable hydrophobic polyester used for cargo encapsulation, and a hydrophilic polymer composed of oligo ethylene glycol chains (triethylene glycol methyl ether methacrylate, TEGMA), which provides stability and repellent properties with added thermo-responsiveness. The PLA-b-PTEGMA block copolymers were synthesized using ring-opening polymerization (ROP) and reversible addition-fragmentation chain transfer (RAFT) polymerization (ROP-RAFT), resulting in varying ratios between the hydrophobic and hydrophilic blocks. Standard techniques, such as size exclusion chromatography (SEC) and ¹H NMR spectroscopy, were used to characterize the block copolymers, while ¹H NMR spectroscopy, 2D nuclear Overhauser effect spectroscopy (NOESY), and dynamic light scattering (DLS) were used to analyze the effect of the hydrophobic PLA block on the LCST of the PTEGMA block in aqueous solutions. The results show that the LCST values for the block copolymers decreased with increasing PLA content in the copolymer. The selected block copolymer presented LCST transitions at physiologically relevant temperatures, making it suitable for manufacturing nanoparticles (NPs) and drug encapsulation-release of the chemotherapeutic paclitaxel (PTX) via temperature-triggered drug release mechanism. The drug release profile was found to be temperature-dependent, with PTX release being sustained at all tested conditions, but substantially accelerated at 37 and 40 °C compared to 25 °C. The NPs were stable under simulated physiological conditions. These findings demonstrate that the addition of hydrophobic monomers, such as PLA, can tune the LCST temperatures of thermo-responsive polymers, and that PLA-b-PTEGMA copolymers have great potential for use in drug and gene delivery systems via temperature-triggered drug release mechanisms in biomedicine applications.

Copper(II)-Incorporated Porphyrin-Based Porous Organic Polymer for a Nonenzymatic Electrochemical Glucose Sensor

To date, the fabrication of multifunctional nanoplatforms based on a porous organic polymer for electrochemical sensing of biorelevant molecules has received considerable attention in the search for a more active, robust, and sensitive electrocatalyst. Here, in this report, we have developed a new porous organic polymer based on porphyrin (TEG-POR) from a polycondensation reaction between a triethylene glycol-linked dialdehyde and pyrrole. The Cu(II) complex of the polymer Cu-TEG-POR shows high sensitivity and a low detection limit for glucose electro-oxidation in an alkaline medium. The characterization of the as-synthesized polymer was done by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and ¹³C CP-MAS solid-state NMR. The N₂ adsorption/desorption isotherm was carried out at 77 K to analyze the porous property. TEG-POR and Cu-TEG-POR both show excellent thermal stability. The Cu-TEG-POR-modified GC electrode shows a low detection limit (LOD) value of 0.9 μM and a wide linear range (0.001-1.3 mM) with a sensitivity of 415.8 μA mM^-1 cm^-2 toward electrochemical glucose sensing. The interference of the modified electrode from ascorbic acid, dopamine, NaCl, uric acid, fructose, sucrose, and cysteine was insignificant. Cu-TEG-POR exhibits acceptable recovery for blood glucose detection (97.25-104%), suggesting its scope in the future for selective and sensitive nonenzymatic glucose detection in human blood.

Enhancement of polyethylene glycol-cell fusion efficiency by novel application of transient pressure using a jet injector

Cell-cell fusion involves the fusion of somatic cells into a single hybrid cell. It is not only a physiological process but also an important cell engineering technology which can be applied to various fields, such as regenerative medicine, antibody engineering, genetic engineering, and cancer therapy. There are three major methods of cell fusion: electrical cell fusion, polyethylene glycol (PEG) cell fusion, and virus-mediated cell fusion. Although PEG cell fusion is the most economical approach and does not require expensive instrumentation, it has a poor fusion rate and induces a high rate of cell cytotoxicity. To improve the fusion rate of the PEG method, we combined it with the pyro-drive jet injector (PJI). PJI provides instant pressure instead of cell agitation to increase the probability of cell-to-cell contact and shorten the distance between cells in the process of cell fusion. Here, we report that this improved fusion method not only decreased cell cytotoxicity during the fusion process, but also increased fusion rate compared with the conventional PEG method. Furthermore, we tested the functionality of cells fused using the PJI-PEG method and found them to be comparable to those fused using the conventional PEG method in terms of their application for dendritic cell (DC)-tumor cell fusion vaccine production; in addition, the PJI-PEG method demonstrated excellent performance in hybridoma cell preparation. Taken together, our data indicate that this method improves cell fusion efficiency as compared to the PEG method and thus has the potential for use in various applications that require cell fusion technology.

Are Natural Compounds a Promising Alternative to Synthetic Cross-Linking Agents in the Preparation of Hydrogels?

The main aim of this review is to assess the potential use of natural cross-linking agents, such as genipin, citric acid, tannic acid, epigallocatechin gallate, and vanillin in preparing chemically cross-linked hydrogels for the biomedical, pharmaceutical, and cosmetic industries. Chemical cross-linking is one of the most important methods that is commonly used to form mechanically strong hydrogels based on biopolymers, such as alginates, chitosan, hyaluronic acid, collagen, gelatin, and fibroin. Moreover, the properties of natural cross-linking agents and their advantages and disadvantages are compared relative to their commonly known synthetic cross-linking counterparts. Nowadays, advanced technologies can facilitate the acquisition of high-purity biomaterials from unreacted components with no additional purification steps. However, while planning and designing a chemical process, energy and water consumption should be limited in order to reduce the risks associated with global warming. However, many synthetic cross-linking agents, such as N,N'-methylenebisacrylamide, ethylene glycol dimethacrylate, poly (ethylene glycol) diacrylates, epichlorohydrin, and glutaraldehyde, are harmful to both humans and the environment. One solution to this problem could be the use of bio-cross-linking agents obtained from natural resources, which would eliminate their toxic effects and ensure the safety for humans and the environment.

Proteoid biodynamers for safe mRNA transfection via pH-responsive nanorods enabling endosomal escape

The recent success of mRNA vaccines using lipid-based vectors highlights the importance of strategies for nucleotide delivery under the pandemic situation. Although current mRNA delivery is focused on lipid-based vectors, still they need to be optimized for increasing stability, targeting, and efficiency, and for reducing toxicity. In this regard, other vector systems featuring smart strategies such as pH-responsive degradability and endosomal escape ability hold the potential to overcome the current limitations. Here, we report pH-responsive polymeric nanorods made of amino acid-derivatives connected by dynamic covalent bonds called proteoid-biodynamers, as mRNA vectors. They show excellent biocompatibility due to the biodegradation, and outstanding transfection. The biodynamers of Lys, His, and Arg or monomer mixtures thereof were shown to form nanocomplexes with mRNA. They outperformed conventional transfection agents three times regarding transfection efficacy in three human cell lines, with 82-98% transfection in living cells. Also, we confirmed that the biodynamers disrupted the endosomes up to 10-fold more in number than the conventional vectors. We discuss here their outstanding performance with a thorough analysis of their nanorod structure changes in endosomal microenvironments.

Micelle and Nanotape Formation of Benzene Tricarboxamide Analogues with Selective Cancer Cell Cytotoxicity

Analogues of benzene-1,3,5-tricarboxamide bearing combinations of different alkyl chains (dodecyl to octadecyl) and ester-linked PEG (polyethylene glycol) chains are shown to self-assemble into either micelles or nanotapes in aqueous solution, depending on the architecture (number of alkyl vs PEG chains). The cytotoxicity to cells is selectively greater for breast cancer cells than fibroblast controls in a dose-dependent manner. The compounds show strong stability, retaining their self-assembled structures at low pH (relevant to acidic tumor conditions) and in buffer and cell culture media.

Tailoring polyvinyl alcohol-sodium alginate (PVA-SA) hydrogel beads by controlling crosslinking pH and time

Hydrogel-encapsulated catalysts are an attractive tool for low-cost intensification of (bio)-processes. Polyvinyl alcohol-sodium alginate hydrogels crosslinked with boric acid and post-cured with sulfate (PVA-SA-BS) have been applied in bioproduction and water treatment processes, but the low pH required for crosslinking may negatively affect biocatalyst functionality. Here, we investigate how crosslinking pH (3, 4, and 5) and time (1, 2, and 8 h) affect the physicochemical, elastic, and process properties of PVA-SA-BS beads. Overall, bead properties were most affected by crosslinking pH. Beads produced at pH 3 and 4 were smaller and contained larger internal cavities, while optical coherence tomography suggested polymer cross-linking density was higher. Optical coherence elastography revealed PVA-SA-BS beads produced at pH 3 and 4 were stiffer than pH 5 beads. Dextran Blue release showed that pH 3-produced beads enabled higher diffusion rates and were more porous. Last, over a 28-day incubation, pH 3 and 4 beads lost more microspheres (as cell proxies) than beads produced at pH 5, while the latter released more polymer material. Overall, this study provides a path forward to tailor PVA-SA-BS hydrogel bead properties towards a broad range of applications, such as chemical, enzymatic, and microbially catalyzed (bio)-processes.

Cytotoxicity evaluation of poly(ethylene) oxide nanofibre in MCF-7 breast cancer cell line

Biocompatible polymers have received significant interest from researchers for their potential in diagnostic applications. This type of polymer can perform with an appropriate host response or carrier for a specific purpose. The current study aims to fabricate and characterise poly(ethylene) oxide (PEO) nanofibres with different concentrations for cytotoxicity evaluation in human breast cancer cell lines (MCF-7) and to get an optimal PEO nanofibre concentration (permissible limit) as a suitable polymer matrix or carrier with potential use in diagnostic applications. The fabrication of PEO nanofibres was done using electrospinning and was characterised by structure and morphology, surface roughness, chemical bonding and release profiles. The functional effects of PEO nanofibres were evaluated with MTS assay and colony formation assay in MCF-7 cells. The results showed that viscosity plays a vital role in synthesising a polymer solution in electrospinning for producing beadless nanofibrous mats ranging from 4.7 Pa·s to 77.7 Pa·s. As the PEO concentration increases, the nanofibre diameter and thickness will increase, but the surface roughness will be decreased. The average fibre diameter for 5 wt% PEO, 6 wt% PEO and 7 wt% PEO nanofibres were 129 ± 70 nm, 185 ± 55 nm and 192 ± 53 nm, respectively. In addition, the fibre thickness for 4 wt% PEO, 5 wt% PEO, 6 wt% PEO and 7 wt% PEO nanofibres were 269 ± 3 μm, 664 ± 4 μm, 758 ± 7 μm and 1329 ± 44 μm, respectively. Contrarily, the surface roughness for 4 wt% PEO, 5 wt% PEO, 6 wt% PEO and 7 wt% PEO nanofibres were 55.6 ± 9 nm, 42.8 ± 6 nm, 42.7 ± 7 nm and 36.6 ± 1 nm, respectively. PEO nanofibres showed the same burst release pattern and rate due to the same molecular weight of PEO with a stable release rate profile after 15 min. It also demonstrates that the percentage of PEO nanofibre release increased with the increasing PEO concentration due to the fibre diameter and thickness. The findings showed that all PEO nanofibres formulations were non-toxic to MCF-7 cells. It is suggested that 5 wt% PEO nanofibre exhibited non-cytotoxic characteristics by maintaining the cell viability from dose 0-1000 μg/ml and did not induce the number of colonies. Therefore, 5 wt% PEO nanofibre is the optimal nanofibre concentration and was suggested as a suitable base polymer matrix or carrier with potential use for diagnostic purposes. The findings in this study have demonstrated the influence of cell growth and viability, including the effects of PEO nanofibre formulations on cancer progress characteristics to achieve a permissible PEO nanofibre concentration limit that can be a benchmark in medical applications, particularly diagnostic applications.

Antigen stabilizing hydrogels based on cyclodextrins and polyethylene glycol act as type-2 adjuvants with suppressed local irritation

Recent viral pandemics have increased global demand for vaccines. However, the supply of effective and safe vaccine not only to developed countries but also developing countries with inadequate storage equipment is still challenging due to the lack of robust systems which improve the efficacy and the stability of vaccines with few side effects. In our previous study, polypseudorotaxane (PPRX) hydrogels based on cyclodextrin (CyD) and polyethylene glycol (PEG) significantly improved the stability of antibody preparations and showed no serious adverse effects after subcutaneous injection, suggesting the possibility as safe vaccine formulations to stabilize an antigen protein. Moreover, recent studies have reported that one of the CyD derivatives, hydroxypropyl-β-CyD (HP-β-CyD), acts as an adjuvant to enhance protective type-2 immune responses. However, it is still unknown that CyD PPRX hydrogels enhance not only the stability of an antigen protein but also its immunogenicity with tolerable side effects. Here, we demonstrate that α- and γ-CyD PPRX hydrogels containing an antigen protein significantly induce antigen-specific type-2 immune responses. Moreover, α- and γ-CyD PPRX hydrogels showed negligible local irritation at the injection site, although subcutaneous injection of α-CyD alone induced skin lesion. Finally, shaking stability of the antigen protein at room temperature was significantly improved by being included in α- and γ-CyD PPRX hydrogels. These results propose the possibility of α- and γ-CyD PPRX hydrogels as novel vaccine formulations which improve both the immunogenicity and stability of an antigen protein with suppressed local irritation.

Approaches towards biomaterial-mediated gene editing for cancer immunotherapy

Gene therapies are transforming treatment modalities for many human diseases and disorders, including those in ophthalmology, oncology, and nephrology. To maximize the clinical efficacy and safety of these treatments, consideration of both delivery materials and cargos is critical. In consideration of the former, a large effort has been placed on transitioning away from potentially immunoreactive and toxic viral delivery mechanisms towards safer and highly tunable nonviral delivery mechanisms, including polymeric, lipid-based, and inorganic carriers. This change of paradigm does not come without obstacles, as efficient non-viral delivery is challenging, particularly to immune cells, and has yet to see clinical translation breakthroughs for gene editing. This mini-review describes notable examples of biomaterial-based gene delivery to immune cells, with emphasis on recent in vivo successes. In consideration of delivery cargos, clustered regularly interspaced palindromic repeat (CRISPR) technology is reviewed and its great promise in the field of immune cell gene editing is described. This mini-review describes how leading non-viral delivery materials and CRISPR technology can be integrated together to advance its clinical potential for therapeutic gene transfer to immune cells to treat cancer.

Sponges from Plasma Treated Cellulose Nanofibers Grafted with Poly(ethylene glycol)methyl Ether Methacrylate

In this work, cellulose nanofibers (CNF) were surface treated by plasma and grafted with poly(ethylene glycol)methyl ether methacrylate (PEGMMA) for increasing mechanical strength and hydrophobicity. The surface characteristics of the sponges were studied by scanning electron microscopy, micro-computed tomography, and Fourier transform infrared spectroscopy, which demonstrated successful surface modification. Plasma treatment applied to CNF suspension led to advanced defibrillation, and the resulting sponges (CNFpl) exhibited smaller wall thickness than CNF. The grafting of PEGMMA led to an increase in the wall thickness of the sponges and the number of larger pores when compared with the non-grafted counterparts. Sponges with increased hydrophobicity demonstrated by an almost 4 times increase in the water contact angle and better mechanical strength proved by 2.5 times increase in specific compression strength were obtained after PEGMMA grafting of plasma treated CNF. Cells cultivated on both neat and PEGMMA-grafted CNF sponges showed high viability (>99%). Remarkably, CNF grafted with PEGMMA showed better cell viability as compared with the untreated CNF sample; this difference is statistically significant (p < 0.05). In addition, the obtained sponges do not trigger an inflammatory response in macrophages, with TNF-α secretion by cells in contact with CNFpl, CNF-PEGMMA, and CNFpl-PEGMMA samples being lower than that observed for the CNF sample. All these results support the great potential of cellulose nanofibers surface treated by plasma and grafted with PEGMMA for biomedical applications.

Molecularly Imprinted Ligand-Free Nanogels for Recognizing Bee Venom-Originated Phospholipase A2 Enzyme

In this study, ligand-free nanogels (LFNGs) as potential antivenom mimics were developed with the aim of preventing hypersensitivity and other side effects following massive bee attacks. For this purpose, poly (ethylene glycol) diacrylate was chosen as a main synthetic biocompatible matrix to prepare the experimental LFNGs. The overall concept uses inverse mini-emulsion polymerization as the main route to deliver nanogel caps with complementary cavities for phospholipase A2 (PLA2) from bee venom, created artificially with the use of molecular imprinting (MI) technologies. The morphology and the hydrodynamic features of the nanogels were confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. The following rebinding experiments evidenced the specificity of molecularly imprinted LFNG for PLA2, with rebinding capacities up to 8-fold higher compared to the reference non-imprinted nanogel, while the in vitro binding assays of PLA2 from commercial bee venom indicated that such synthetic nanogels are able to recognize and retain the targeted PLA2 enzyme. The results were finally collaborated with in vitro cell-viability experiments and resulted in a strong belief that such LFNG may actually be used for future therapies against bee envenomation.

Polyethylene glycol (PEG): The nature, immunogenicity, and role in the hypersensitivity of PEGylated products

Polyethylene glycol (PEG) is a versatile polymer that is widely used as an additive in foods and cosmetics, and as a carrier in PEGylated therapeutics. Even though PEG is thought to be less immunogenic, or perhaps even non-immunogenic, with a variety of physicochemical properties, there is mounting evidence that PEG causes immunogenic responses when conjugated with other materials such as proteins and nanocarriers. Under these conditions, PEG with other materials can result in the production of anti-PEG antibodies after administration. The antibodies that are induced seem to have a deleterious impact on the therapeutic efficacy of subsequently administered PEGylated formulations. In addition, hypersensitivity to PEGylated formulations could be a significant barrier to the utility of PEGylated products. Several reports have linked the presence of anti-PEG antibodies to incidences of complement activation-related pseudoallergy (CARPA) following the administration of PEGylated formulations. The use of COVID-19 mRNA vaccines, which are composed mainly of PEGylated lipid nanoparticles (LNPs), has recently gained wide acceptance, although many cases of post-vaccination hypersensitivity have been documented. Therefore, our review focuses not only on the importance of PEGs and its great role in improving the therapeutic efficacy of various medications, but also on the hypersensitivity reactions attributed to the use of PEGylated products that include PEG-based mRNA COVID-19 vaccines.

Regulable Supporting Baths for Embedded Printing of Soft Biomaterials with Variable Stiffness

Three-dimensional (3D) embedded printing is emerging as a potential solution for the fabrication of complex biological structures and with ultrasoft biomaterials. For the supporting medium, bulk gels can support a wide range of bioinks with higher printing resolution as well as better finishing surfaces than granular microgel baths. However, the difficulties of regulating the physical properties of existing bulk gel supporting baths limit the further development of this method. This work has developed a bulk gel supporting bath with easily regulable physical properties to facilitate soft-material fabrication. The proposed bath is composed based on the hydrophobic association between a hydrophobically modified hydroxypropylmethyl cellulose (H-HPMC) and Pluronic F-127 (PF-127). Its rheological properties can be easily regulated; in the preprinting stage by varying the relative concentration of components, during printing by changing the temperature, and postprinting by adding additives with strong hydrophobicity or hydrophilicity. This has made the supporting bath not only available for various bioinks with a range of printing windows but also easy to be removed. Also, the removal strategy is independent of printing conditions like temperature and ions, which empowers the bath to hold great potential for the embedded printing of commonly used biomaterials. The adjustable rheological properties of the bath were leveraged to characterize the embedded printing quantitatively, involving the disturbance during the printing, filament cross-sectional shape, printing resolution, continuity, and the coalescence between adjacent filaments. The match between the bioink and the bath was also explored. Furthermore, low-viscosity bioinks (with 0.008-2.4 Pa s viscosity) were patterned into various 3D complex delicate soft structures (with a 0.5-5 kPa compressive modulus). It is believed that such an easily regulable assembled bath could serve as an available tool to support the complex biological structure fabrication and open unique prospects for personalized medicine.

Characterisation of products from EDC-mediated PEG substitution of chitosan allows optimisation of reaction conditions

PEGylation is a common method use to modify the physiochemical properties and increase the solubility of chitosan (CHI). Knowledge of optimal reaction conditions for PEGylation of CHI underpins its ongoing use in nanomedicine. This study synthesised methoxy polyethylene glycol grafted CHI (mPEG-CHI) using carbodiimide-mediated coupling. The effect of reagent concentrations and pH on the degree of substitution (DS) and the PEGylation yield (conversion of free PEG to conjugated PEG) was evaluated through detailed chemical characterisation. Within the parameter space investigated, optimised reaction conditions (NH₂: COOH:NHS:EDC of 3.5:1:1:10, pH = 5) resulted in a DS of 24 % and a PEGylation yield of 84 %. An EDC-derived adduct formed at pH ≥ 5.5 and a at 15-fold excess of EDC relative to COOH. The adduct was evaluated to be a guanidine derivative formed by the reaction of the amine group of CHI directly with EDC. DS ≥ 12 imparted water solubility to CHI at physiological pH and mPEG-CHI (0.2-1.0 mg/mL) was not cytotoxic against the breast cancer cell lines MCF-7 and MDA-MB-231, indicating its suitability for medical applications.

Functional properties of thermally tampered poly(ethylene oxide)

Introduction: Poly(ethylene oxide) (PEO) is the most common polymer used in commercial abuse-deterrent tablets. Due to its vulnerability to high-temperature manipulation, we investigated abuse-deterrent capability and the toxicity of this polymer upon thermal treatments at 80°C and 180°C for 1 hour. Methods: Tablets (200 mg PEO and 300 mg Avicel®) were directly compressed under 2000 lb. The thermally manipulated PEOs were evaluated for their viscosity, crushability, structural changes, and cell toxicity. Results: Our findings showed that 180°C-treated tablets underwent some degrees of oxidative degradation with profound toxicity in both mesenchymal stem cells and MG63 cells. The 180°C-treated tablets exhibited almost no resistance against crushing and were prone to abuse. While thermal processing of PEO at around its melting temperature is a common approach to enhance crush resistance of its dosage forms, thermal manipulation at close to the PEO's oxidation temperature can lead to structural changes, dramatic loss of crush and extraction resistance, and significant cell toxicity. Conclusion: Similar to the low molecular weight PEO, when thermally manipulated at its thermo-oxidative temperature, the high molecular weight PEO loses its deterrence performance and causes severe cell toxicity.

Functionalized SPION immobilized on graphene-oxide: Anticancer and antiviral study

The progressive and fatal outbreak of some diseases such as cancer and coronavirus necessitates using advanced materials to bring such devastating illnesses under control. In this study, graphene oxide (GO) is decorated by superparamagnetic iron oxide nanoparticles (SPION) (GO/SPION) as well as polyethylene glycol functionalized SPION (GO/SPION@PEG), and chitosan functionalized SPION (GO/SPION@CS). Field emission scanning electron microscopic (FESEM) images show the formation of high density uniformly distributed SPION nanoparticles on the surface of GO sheets. The structural and chemical composition of nanostructures is confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The saturation magnetization of GO/SPION, GO/SPION@PEG and GO- SPION@CS are found to be 20, 19 and 8 emu/g using vibrating sample magnetometer. Specific absorption rate (SAR) values of 305, 283, and 199 W/g and corresponding intrinsic loss power (ILP) values of 9.4, 8.7, and 6.2 nHm²kg^-1 are achieved for GO/SPION, GO/SPION@PEG and GO/SPION@CS, respectively. The In vitro cytotoxicity assay indicates higher than 70% cell viability for all nanostructures at 100, 300, and 500 ppm after 24 and 72 h. Additionally, cancerous cell (EJ138 human bladder carcinoma) ablation is observed using functionalized GO/SPION under applied magnetic field. More than 50% cancerous cell death has been achieved for GO/SPION@PEG at 300 ppm concentration. Furthermore, Surrogate virus neutralization test is applied to investigate neutralizing property of the synthesized nanostructures through analysis of SARS-CoV-2 receptor-binding domain and human angiotensin-converting enzyme 2 binding. The highest level of SARS-CoV-2 virus inhibition is related to GO/SPION@CS (86%) due to the synergistic exploitation of GO and chitosan. Thus, GO/SPION and GO/SPION@PEG with higher SAR and ILP values could be beneficial for cancer treatment, while GO/SPION@CS with higher virus suppression has potential to use against coronaviruses. Thus, the developed nanocomposites have a potential in the efficient treatment of cancer and coronavirus.

A versatile embedding medium for freeform bioprinting with multi-crosslinking methods

Embedded freeform writing addresses the contradiction between the material printability and biocompatibility for conventional extrusion-based bioprinting. However, the existing embedding mediums have limitations concerning the restricted printing temperature window, compatibility with bioinks or crosslinkers, and difficulties on medium removal. This work demonstrates a new embedding medium to meet the above demands, which composes of hydrophobically modified hydroxypropylmethyl cellulose (H-HPMC) and Pluronic F-127 (PF-127). The adjustable hydrophobic and hydrophilic associations between the components permit tunable thermoresponsive rheological properties, providing a programable printing window. These associations are hardly compromised by additives without strong hydrophilic groups, which means it is compatible with the majority of bioink choices. We use polyethylene glycol 400, a strong hydrophilic polymer, to facilitate easy medium removal. The proposed medium enables freeform writing of the millimetric complex tubular structures with great shape fidelity and cell viability. Moreover, five bioinks with up to five different crosslinking methods are patterned into arbitrary geometries in one single medium, demonstrating its potential in heterogeneous tissue regeneration. Utilizing the rheological properties of the medium, an enhanced adhesion writing method is developed to optimize the structure's strand-to-strand adhesion. In summary, this versatile embedding medium provides excellent compatibility with multi-crosslinking methods and a tunable printing window, opening new opportunities for heterogeneous tissue regeneration.

Influence of PEG-coated Bismuth Oxide Nanoparticles on ROS Generation by Electron Beam Radiotherapy

Introduction: Nanoparticles (NPs) have been proven to enhance radiotherapy doses as radiosensitizers. The introduction of coating materials such as polyethylene glycol (PEG) to NPs could impact the NPs’ biocompatibility and their effectiveness as radiosensitizers. Optimization of surface coating is a crucial element to ensure the successful application of NPs as a radiosensitizer in radiotherapy. This study aims to investigate the influence of bismuth oxide NPs (BiONPs) coated with PEG on reactive oxygen species (ROS) generation on HeLa cervical cancer cell line.

Material and methods: Different PEG concentrations (0.05, 0.10, 0.15 and 0.20 mM) were used in the synthesis of the NPs. The treated cells were irradiated with 6 and 12 MeV electron beams with a delivered dose of 3 Gy. The reactive oxygen species (ROS) generation was measured immediately after and 3 hours after irradiation.

Results: The intracellular ROS generation was found to be slightly influenced by electron beam energy and independent of the PEG concentrations. Linear increments of ROS percentages over the 3 hours of incubation time were observed.

Conclusions: Finally, the PEG coating might not substantially affect the ROS generated and thus emphasizing the functionalized BiONPs application as the radiosensitizer for electron beam therapy.

Antibacterial and hemostatic capacities of cellulose nanocrystalline-reinforced poly(vinyl alcohol) electrospun mats doped with Tiger 17 and pexiganan peptides for prospective wound healing applications

Infection is a major issue in chronic wound care. Different dressings have been developed to prevent microbial propagation, but an effective, all-in-one (cytocompatible, antimicrobial and promoter of healing) solution is still to be uncovered. In this research, polyvinyl alcohol (PVA) nanofibrous mats reinforced with cellulose nanocrystal (CNC), at 10 and 20% v/v ratios, were produced by electrospinning, crosslinked with glutaraldehyde vapor and doped with specialized peptides. Crosslinking increased the mats' fiber diameters but maintained their bead-free morphology. Miscibility between polymers was confirmed by Fourier-transform infrared spectroscopy and thermal evaluations. Despite the incorporation of CNC having reduced the mats' mechanical performance, it improved the mats' surface energy and its structural stability over time. Pexiganan with an extra cysteine group was functionalized onto the mats via hydroxyl- polyethylene glycol 2-maleimide, while Tiger 17 was physisorbed to preserve its cyclic conformation. Antimicrobial assessments demonstrated the peptide-doped mat's effectiveness against Staphylococcus aureus and Pseudomonas aeruginosa; pexiganan contributed mostly for such outcome. Tiger 17 showed excellent capacity in accelerating clotting. Cytocompatibility evaluations attested to these mats' safety. C90/10 PVA/CNC mats were deemed the most effective from the tested group and, thus, a potentially effective option for chronic wound treatments.

Tiger 17 and pexiganan as antimicrobial and hemostatic boosters of cellulose acetate-containing poly(vinyl alcohol) electrospun mats for potential wound care purposes

In this research, we propose to engineer a nanostructured mat that can simultaneously kill bacteria and promote an environment conducive to healing for prospective wound care. Polyvinyl alcohol (PVA) and cellulose acetate (CA) were combined at different polymer ratios (100/0, 90/10, 80/20% v/v), electrospun and crosslinked with glutaraldehyde vapor. Crosslinked fibers increased in diameter (from 194 to 278 nm), retaining their uniform structure. Fourier-transform infrared spectroscopy and thermal analyses proved the excellent miscibility between polymers. CA incorporation incremented the fibers swelling capacity and reduced the water vapor and air permeabilities of the mats, preventing the excessive drying of wounds. The antimicrobial peptide cys-pexiganan and the immunoregulatory peptide Tiger 17 were incorporated onto the mats via polyethylene glycol spacer (hydroxyl-PEG2-maleimide) and physisorbed, respectively. Time-kill kinetics evaluations revealed the mats effectiveness against Staphylococcus aureus and Pseudomonas aeruginosa. Tiger 17 played a major role in accelerating clotting of re-calcified plasma. Data reports for the first time the collaborative effect of pexiganan and Tiger 17 against bacterial infections and in boosting hemostasis. Cytocompatibility data verified the peptide-modified mats safety. Croslinked 90/10 PVA/CA mats were deemed the most promising combination due to their moderate hydrophilicity and permeabilities, swelling capacity, and high yields of peptide loading.

Exploring In Vitro Biological Cellular Responses of Pegylated β-Cyclodextrins

βCDPEG5 and βCDPEG2 are two derivatives comprising seven PEG linear chains of 5 and 2 kDa, respectively, conjugated to βCD. As βCDPEGs display different physicochemical properties than their precursors, they could also trigger distinct cellular responses. To investigate the biological behavior of βCDPEGs in comparison to their parent compounds, we performed broad toxicological assays on RAW 264.7 macrophages, MC3T3-E1 osteoblasts, and MDCK cells. By analyzing ROS and NO₂⁻ overproduction in macrophages, we found that βCDPEGs induced a moderate stress response without affecting cell viability. Although MC3T3-E1 osteoblasts were more sensitive than MDCK cells to βCDPEGs and the parent compounds, a similar pattern was observed: the effect of βCDPEG5 on cell viability and cell cycle progression was larger than that of βCDPEG2; PEG2 affected cell viability and cell cycle more than βCDPEG2; cell post-treatment recovery was favorable in all cases, and the compounds had similar behaviors regarding ROS generation. The effect on MDCK cell migration followed a similar pattern. In contrast, for osteoblasts, the interference of βCDPEG5 with cell migration was smaller than that of βCDPEG2; likewise, the effect of PEG2 was shorter than its conjugate. Overall, the covalent conjugation of βCD and PEGs, particularly to yield βCDPEG2, improved the biocompatibility profile, evidencing that a favorable biological response can be tuned through a thoughtful combination of materials. Moreover, this is the first time that an in vitro evaluation of βCD and PEG has been presented for MC3T3-E1 and MDCK cells, thus providing valuable knowledge for designing biocompatible nanomaterials constructed from βCD and PEGs.

Nanogap-containing thermo-plasmonic nano-heaters for amplified photo-triggered tumor ablation at low laser power density

Herein, nanogap amplified plasmonic heat-generators are fabricated by decorating Pt nanodots on gold nanospheres (GNSs@Pt@mPEG) by maintaining strategic nano-gaps (1-2 nm) and studied precisely for plasmonic photothermal therapy (PPTT) of colon cancer by passive tumor targeting. The surface modification of GNSs@Pt with poly(ethylene glycol) methyl ether thiol (mPEG) increases their accumulation in tumor cells and hence the GNSs@Pt@mPEG stay at the tumor site for a longer time. The nanogap amplified GNSs@Pt@mPEG (O.D. = 4.0) generated high plasmonic photothermal hyperthermia and utilized a low NIR power density (0.36 W cm^-2) for the elimination of tumor cells in only 150 s of irradiation time and shows excellent colloidal and photo-stability. The predominant distribution of GNSs@Pt@mPEG caused effective tumor cell death and promoted uniform treatment on tumor sites. In vivo studies demonstrated that the GNSs@Pt@mPEG have very low toxicity, high biocompatibility, and thermal stability, stay longer at the tumor site, induce tumor cell death without side effects, and show significantly less uptake in other organs except for the spleen. The significant accumulations and longer stay suggested that they are favorable for tumor passive uptake and the possibility of enhanced PPTT after intravenous administration. The nano-particles were stable up to O.D. 200 and have at least 12 months shelf-life without losing colloidal stability or photothermal efficacy. These findings lay the groundwork for using GNSs@Pt@mPEG as a NIR light-responsive PPTT agent and demonstrated their potential for further use in clinical applications.

Characterization of an engineered mucus microenvironment for in vitro modeling of host-microbe interactions

The human mucus layer plays a vital role in maintaining health by providing a physical barrier to pathogens. This biological hydrogel also provides the microenvironment for commensal bacteria. Common models used to study host–microbe interactions include gnotobiotic animals or mammalian–microbial co-culture platforms. Many of the current in vitro models lack a sufficient mucus layer to host these interactions. In this study, we engineered a mucus-like hydrogel Consisting of a mixed alginate-mucin (ALG-MUC) hydrogel network by using low concentration calcium chloride (CaCl₂) as crosslinker. We demonstrated that the incorporation of ALG-MUC hydrogels into an aqueous two-phase system (ATPS) co-culture platform can support the growth of a mammalian monolayer and pathogenic bacteria. The ALG-MUC hydrogels displayed selective diffusivity against macromolecules and stability with ATPS microbial patterning. Additionally, we showed that the presence of mucin within hydrogels contributed to an increase in antimicrobial resistance in ATPS patterned microbial colonies. By using common laboratory chemicals to generate a mammalian–microbial co-culture system containing a representative mucus microenvironment, this model can be readily adopted by typical life science laboratories to study host–microbe interaction and drug discovery.

Preparation of thyme oil loaded κ-carrageenan-polyethylene glycol hydrogel membranes as wound care system

The present study is aimed at fabricating thyme oil loaded hydrogel membranes composed of κ-carrageenan (CG) and polyethylene glycol (PEG), which can provide moist environment and prevent infections for rapid wound healing. Membranes were prepared with different amounts of PEG via solvent casting technique under ambient conditions. Physicochemical properties of CG-PEG membranes as a function of the PEG content were investigated. The surface morphology of membranes displayed smoother surfaces with increasing PEG content up to 40%. In addition, the interaction of PEG with CG polymer chains was evaluated in terms of Free and bound PEG fraction within the membrane matrix. Furthermore, thyme oil (TO) was added to enhance the antibacterial properties of CG-PEG membranes. These membranes showed >95% antimicrobial activity against both gram-positive and gram-negative bacteria depending on the TO content. Suggesting the great potential of these membranes as a strong candidate for providing an effective antimicrobial nature in human healthcare.

Synthesis and characterization of zinc derivatized 3, 5-dihydroxy 4', 7-dimethoxyflavone and its anti leishmaniasis activity against Leishmania donovani

This study reports the synthesis and characterization of zinc derivatized 3,5-dihydroxy 4', 7- dimethoxyflavone (DHDM-Zn) compound for the development of new antileishmanial agents. The interaction studies of DHDM with zinc were carried out by UV spectra and fluorescence spectra analysis. Characterization of the complex was further accomplished by multi-spectroscopic techniques such as FTIR, Raman, HRMS, NMR, FESEM-EDX. The morphological and topographical studies of synthesized DHDM-Zn were carried out using FESEM with EDX. Further, it was demonstrated that DHDM-Zn exhibited an excellent in vitro antagonistic effect against the promastigote form of L. donovani. In addition, the possible mechanisms of promastigote L. donovani cell death, by involvement of derivatized compound in arrest of the cell cycle in the G1 phase and residual cell count reduction were investigated. Promastigote growth kinetics performed in the presence of the derivatized compound revealed a slow growth rate. The combination of growth kinetics and cell cycle analysis, made it possible to interpret and classify the cause of leishmanial cell death accurately. These results support that zinc derivatized complex (DHDM-Zn) might work as a lead compound for designing and developing a new antileishmanial drug.