Identification of possible cytotoxicity mechanism of polyethylenimine by proteomics analysis

Effect of Surface Modification of Gold Nanoparticles Loaded with Small Nucleic Acid Sequences on Cytotoxicity and Uptake: A Comparative Study In Vitro

Nanoparticle technology, particularly gold nanoparticles (AuNPs), is being developed for a wide range of applications, including as a delivery system of peptides or nucleic acids (NA). Their use in precision medicine requires detailed engineering of NP functionalization to optimize their function and minimize off-target toxicity. Two main routes can be found in the literature for the attachment of NA strands to AuNPs: covalent binding via a thiol group or passive adsorption onto a specially adapted coating previously applied to the metallic core. In this latter case, the coating is often a positively charged polymer, as polyethylenimine, which due to its high positive charge can induce cytotoxicity. Here, we investigated an innovative strategy based on the initial coating of the particles using calix[4]arene macrocycles bearing polyethylene glycol chains as an interesting alternative to polyethylenimine for NA adsorption. Because any molecular modification of AuNPs may affect the cytotoxicity and cellular uptake, we compared the behavior of these AuNPs to that of particles obtained via a classical thiol covalent attachment in MCF-7 and GC-1 spg cell lines. We showed a high biocompatibility of both AuNPs-NA internalized in vitro. The difference in subcellular localization of both AuNPs-NA in MCF-7 cells compared to GC-1 spg cells suggests that their subcellular target is cell- and coating-dependent. This finding provides valuable insights for developing alternative NA delivery systems with a high degree of tunability.

Polyelectrolyte Complex Coacervate Adhesive for Wearable Medical Devices

Wearable electronics are becoming increasingly popular for personalized healthcare. These devices often use hydrophobic, pressure-sensitive adhesives to adhere to various parts of the body. With prolonged skin contact, commercial adhesives have been shown to cause allergic contact dermatitis as well as significant loss of adhesive strength when exposed to moisture and ionic compounds, such as sweat. To address these common issues, the development of a polyelectrolyte-based skin adhesive for wearable devices is underway. Here, it is demonstrated how coacervation is induced with a system composed of polyethylenimine (PEI) and sodium hexametaphosphate (PSP) as the counter polyelectrolyte. The coacervate is deposited onto a polyurethane film to form an effective adhesive that is mechanically comparable to a commercially available one, offering a promising alternative for wearable devices.

Clinical challenges in bone tissue engineering - A narrative review

Bone tissue engineering (BTE) has emerged as a promising approach to address large bone defects caused by trauma, infections, congenital malformations, and tumors. This review focuses on scaffold design, cell sources, growth factors, and vascularization strategies, highlighting their roles in developing effective treatments. We explore the complexities of balancing mechanical properties, porosity, and biocompatibility in scaffold materials, alongside optimizing mesenchymal stem cell delivery methods. The critical role of growth factors in bone regeneration and the need for controlled release systems are discussed. Vascularization remains a significant hurdle, with strategies such as angiogenic factors, co-culture systems, and bioprinting under investigation. Mechanical challenges, tissue responses, and inflammation management are examined, alongside gene therapy's potential for enhancing osteogenesis and angiogenesis via both viral and non-viral delivery methods. The review emphasizes the impact of patient-specific factors on bone healing outcomes and the importance of personalized approaches. Future directions are described, emphasizing the necessity of interdisciplinary cooperation to advance the field of BTE and convert laboratory results into clinically feasible solutions.

Unraveling Cytotoxicity in HEK293 Cells During Recombinant AAV Production for Gene Therapy Applications

Transient transfection of HEK293 cells represents the dominant technique for the production of recombinant adeno-associated virus (AAV) vectors. However, recombinant AAV (rAAV) production is cytotoxic, potentially impacting process performance, product yields, and quality, complicating downstream processing. This study characterizes cell death response for rAAV producing HEK293 cells and explores the potential to control cytotoxicity. Initial analysis of triple transfected cells revealed caspase-mediated apoptosis as a likely mechanism of cellular death. Next, the causes of this cytotoxicity were investigated by dissecting transfection steps. Exposing cells to polyethyleneimine (PEI) alone or complexed with a blank plasmid at typical concentrations had a limited impact on cell growth. However, the inclusion of plasmid constructs containing genes to produce rAAVs triggered significant cell death, with the helper plasmid being the most toxic both independently and in combination with packaging and transgene plasmids. Additionally, apoptosis in transfected cultures could be inhibited using the pan-caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD.fmk), leading to a 65% increase in peak viable cell density (VCD). Although the rAAV genome titer remained relatively unaltered, capsid levels declined upon cell death inhibition. Consequently, the ratio of full to empty capsids, an important product quality attribute (PQA) for rAAVs increased following caspase inhibition. This study provides insights into apoptosis activation in rAAVs and uncovers avenues for its modulation to alter PQAs.

Core-shell upconversion nanoparticles with suitable surface modification to overcome endothelial barrier

Upconversion nanoparticles (UCNPs), capable of converting near-infrared (NIR) light into high-energy emission, hold significant promise for bioimaging applications. However, the presence of tissue barriers poses a challenge to the effective delivery of nanoparticles (NPs) to target organs. In this study, we demonstrate the core-shell UCNPs modified with cationic biopolymer, i.e., N, N-trimethyl chitosan (TMC), can overcome endothelial barriers. The core-shell UCNP is composed of NaGdF4: Yb3+,Tm3+ (16.7 ± 2.7 nm) as core materials and silica (SiO2) shell. The average particle size of UCNPs@SiO2 is estimated at 26.1 ± 3.7 nm. X-ray diffraction (XRD), transmission electron microscopy (TEM) and element mapping shows the formation of hexagonal crystal structure of β-NaGdF4 and elements doping. The surface of UCNPs@SiO2 has been modified with poly(ethylene glycol) (PEG) to enhance water dispersibility and colloidal stability, and further modified with TMC with the zeta potential increasing from -2.1 ± 0.96 mV to 26.9 ± 12.6 mV. No significant toxic effect is imposed to HUVECs when the cells are treated with core-shell UCNPs with surface modification up to 250 µg/mL. The transport ability of the core-shell UCNPs has been evaluated by using the in vitro endothelial barrier model. Transepithelial electrical resistance (TEER) and immunofluorescence staining of tight junction proteins have been employed to verify the integrity of the in vitro endothelial barrier model. The results indicate that the transport percentage of the UCNPs@SiO2 with PEG and TMC through the model is up to 4.56%, which is twice higher than that of the UCNPs@SiO2 with PEG but without TMC and six times that of the UCNPs@SiO2.

Emerging Roles of ncRNAs in Type 2 Diabetes Mellitus: From Mechanisms to Drug Discovery

Type 2 diabetes mellitus (T2DM), a high-incidence chronic metabolic disorder, has emerged as a global health issue, where most patients need lifelong medication. Gaining insights into molecular mechanisms involved in T2DM development is expected to provide novel strategies for clinical prevention and treatment. Growing evidence validates that non-coding RNAs (ncRNAs) including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) function as crucial regulators in multiple biological processes of T2DM, inspiring various potential targets and drug candidates. In this review, we summarize the current understanding of ncRNA roles in T2DM and discuss the potential use of ncRNAs as targets and active molecules for drug discovery.

Self-assembled ROS-triggered Bletilla striata polysaccharide-releasing hydrogel dressing for inflammation-regulation and enhanced tissue-healing

The antimicrobial and pro-healing properties remain critical clinical objectives for skin wound management. However, the escalating problem of antibiotic overuse and the corresponding rise in bacterial resistance necessitates an urgent shift towards an antibiotic-free approach to antibacterial treatment. The quest for antimicrobial efficacy while accelerating wound healing without antibiotic treatment have emerged as innovative strategies in skin wound treatment. Here, a dual-function hydrogel with antimicrobial and enhanced tissue-healing properties was developed by utilizing cyclodextrin, ferrocene, polyethyleneimine (PEI), and Bletilla striata polysaccharide (BSP), through multiple non-covalent interactions, which can intelligently release BSP by recognizing the wound inflammatory microenvironment through the cyclodextrin-ferrocene unit. Moreover, the porosity (65 % - 85 %), Young's modulus (400 KPa - 140 KPa), and DPPH scavenge rate (18 % - 40 %) of the hydrogel are modulated by varying the BSP content. The hydrogel exhibits outstanding antibacterial properties (98.3 % reduction of Escherichia coli observed after exposure to HTFC@BSP-20 for 24 h) and favorable biocompatibility. Furthermore, in a rat full-thickness skin wound model, the dual-function hydrogel significantly accelerates wound healing, increased CD31 expression promotes vascular regeneration, reduced TNF-α express and inhibited the inflammation. This multifunctional ROS responsive hydrogel provides a new perspective for antibiotics-free treatment of skin injuries.

Dihydroxyphenylalanine-conjugated high molecular weight polyethylenimine for targeted delivery of Plasmid

High molecular weight polyethylenimine (HMW PEI; branched 25 kDa PEI) has been widely investigated for gene delivery due to its high transfection efficiency. However, the toxicity and lack of targeting to specific cells have limited its clinical application. In the present investigation, L-3, 4-dihydroxyphenylalanine (L-DOPA) was conjugated on HMW PEI in order to target L-type amino acid transporter 1 (LAT-1) and modulate positive charge density on the surface of polymer/plasmid complexes (polyplexes). The results of biophysical characterization revealed that the PEI conjugates are able to form nanoparticles ≤ 180 nm with the zeta potential ranging from + 9.5-12.4 mV. These polyplexes could condense plasmid DNA and protect it against nuclease digestion at the carrier to plasmid ratios higher than 4. L-DOPA conjugated PEI derivatives were complexed with a plasmid encoding human interleukin-12 (hIL-12). Targeted polyplexes showed up to 2.5 fold higher transfection efficiency in 4T1 murine mammary cancer cell line, which expresses LAT-1, than 25 kDa PEI polyplexes prepared in the same manner. The cytotoxicity of these polyplexes was also substantially lower than the unmodified parent HMW PEI. These results support the use of L-3, 4-dihydroxyphenylalanine derivatives of PEI in any attempt to develop a LAT-1 targeted gene carrier.

The menace of severe adverse events and deaths associated with viral gene therapy and its potential solution

Over the past decade, in vivo gene replacement therapy has significantly advanced, resulting in market approval of numerous therapeutics predominantly relying on adeno-associated viral vectors (AAV). While viral vectors have undeniably addressed several critical healthcare challenges, their clinical application has unveiled a range of limitations and safety concerns. This review highlights the emerging challenges in the field of gene therapy. At first, we discuss both the role of biological barriers in viral gene therapy with a focus on AAVs, and review current landscape of in vivo human gene therapy. We delineate advantages and disadvantages of AAVs as gene delivery vehicles, mostly from the safety perspective (hepatotoxicity, cardiotoxicity, neurotoxicity, inflammatory responses etc.), and outline the mechanisms of adverse events in response to AAV. Contribution of every aspect of AAV vectors (genomic structure, capsid proteins) and host responses to injected AAV is considered and substantiated by basic, translational and clinical studies. The updated evaluation of recent AAV clinical trials and current medical experience clearly shows the risks of AAVs that sometimes overshadow the hopes for curing a hereditary disease. At last, a set of established and new molecular and nanotechnology tools and approaches are provided as potential solutions for mitigating or eliminating side effects. The increasing number of severe adverse reactions and, sadly deaths, demands decisive actions to resolve the issue of immune responses and extremely high doses of viral vectors used for gene therapy. In response to these challenges, various strategies are under development, including approaches aimed at augmenting characteristics of viral vectors and others focused on creating secure and efficacious non-viral vectors. This comprehensive review offers an overarching perspective on the present state of gene therapy utilizing both viral and non-viral vectors.

Synthesis and real-time characterization of self-healing, injectable, fast-gelling hydrogels based on alginate multi-reducing end polysaccharides (MREPs)

Polysaccharide-based hydrogels are promising for many biomedical applications including drug delivery, wound healing, and tissue engineering. We illustrate herein self-healing, injectable, fast-gelling hydrogels prepared from multi-reducing end polysaccharides, recently introduced by the Edgar group. Simple condensation of reducing ends from multi-reducing end alginate (M-Alg) with amines from polyethylene imine (PEI) in water affords a dynamic, hydrophilic polysaccharide network. Trace amounts of acetic acid can accelerate the gelation time from hours to seconds. The fast-gelation behavior is driven by rapid Schiff base formation and strong ionic interactions induced by acetic acid. A cantilever rheometer enables real-time monitoring of changes in viscoelastic properties during hydrogel formation. The reversible nature of these crosslinks (imine bonds, ionic interactions) provides a hydrogel with low toxicity in cell studies as well as self-healing and injectable properties. Therefore, the self-healing, injectable, and fast-gelling M-Alg/PEI hydrogel holds substantial promise for biomedical, agricultural, controlled release, and other applications.

Recent advances in gene delivery nanoplatforms based on spherical nucleic acids

Gene therapy is a therapeutic option for mitigating diseases that do not respond well to pharmacological therapy. This type of therapy allows for correcting altered and defective genes by transferring nucleic acids to target cells. Notably, achieving a desirable outcome is possible by successfully delivering genetic materials into the cell. In-vivo gene transfer strategies use two major classes of vectors, namely viral and nonviral. Both of these systems have distinct pros and cons, and the choice of a delivery system depends on therapeutic objectives and other considerations. Safe and efficient gene transfer is the main feature of any delivery system. Spherical nucleic acids (SNAs) are nanotechnology-based gene delivery systems (i.e., non-viral vectors). They are three-dimensional structures consisting of a hollow or solid spherical core nanoparticle that is functionalized with a dense and highly organized layer of oligonucleotides. The unique structural features of SNAs confer them a high potency in internalization into various types of tissue and cells, a high stability against nucleases, and efficay in penetrating through various biological barriers (such as the skin, blood-brain barrier, and blood-tumor barrier). SNAs also show negligible toxicity and trigger minimal immune response reactions. During the last two decades, all these favorable physicochemical and biological attributes have made them attractive vehicles for drug and nucleic acid delivery. This article discusses the unique structural properties, types of SNAs, and also optimization mechanisms of SNAs. We also focus on recent advances in the synthesis of gene delivery nanoplatforms based on the SNAs.

Reproductive toxicity assessment of cellulose nanofibers, citric acid, and branched polyethylenimine in sea urchins: Eco-design of nanostructured cellulose sponge framework (Part B)

In the framework of a safe-by-design approach, we previously assessed the eco-safety of nanostructured cellulose sponge (CNS) leachate on sea urchin reproduction. It impaired gamete quality, gamete fertilization competence, and embryo development possibly due to the leaching of chemical additives used during the CNS synthesis process. To extend this observation and identify the component(s) that contribute to CNS ecotoxicity, in the present study, we individually screened the cytotoxic effects on sea urchin Arbacia lixula and Paracentrotus lividus gametes and embryos of the three main constituents of CNS, namely cellulose nanofibers, citric acid, and branched polyethylenimine. The study aimed to minimize any potential safety risk of these components and to obtain an eco-safe CNS. Among the three CNS constituents, branched polyethylenimine resulted in the most toxic agent. Indeed, it affected the physiology and fertilization competence of male and female gametes as well as embryo development in both sea urchin species. These results are consistent with those previously reported for CNS leachate. Moreover, the characterisation of CNS leachate confirmed the presence of detectable branched polyethylenimine in the conditioned seawater even though in a very limited amount. Altogether, these data indicate that the presence of branched polyethylenimine is a cause-effect associated with a significant risk in CNS formulations due to its leaching upon contact with seawater. Nevertheless, the suggested safety protocol consisting of consecutive leaching treatments and conditioning of CNS in seawater can successfully ameliorate the CNS ecotoxicity while maintaining the efficacy of its sorbent properties supporting potential environmental applications.

Nanomedicine-induced cell pyroptosis to enhance antitumor immunotherapy

Immunotherapy is a therapeutic modality designed to elicit or augment an immune response against malignancies. Despite the immune system's ability to detect and eradicate neoplastic cells, certain neoplastic cells can elude immune surveillance and elimination through diverse mechanisms. Therefore, antitumor immunotherapy has emerged as a propitious strategy. Pyroptosis, a type of programmed cell death (PCD) regulated by Gasdermin (GSDM), is associated with cytomembrane rupture due to continuous cell expansion, which results in the release of cellular contents that can trigger robust inflammatory and immune responses. The field of nanomedicine has made promising progress, enabling the application of nanotechnology to enhance the effectiveness and specificity of cancer therapy by potentiating, enabling, or augmenting pyroptosis. In this review, we comprehensively examine the paradigms underlying antitumor immunity, particularly paradigms related to nanotherapeutics combined with pyroptosis; these treatments include chemotherapy (CT), hyperthermia therapy, photodynamic therapy (PDT), chemodynamic therapy (CDT), ion-interference therapy (IIT), biomimetic therapy, and combination therapy. Furthermore, we thoroughly discuss the coordinated mechanisms that regulate these paradigms. This review is expected to enhance the understanding of the interplay between pyroptosis and antitumor immunotherapy, broaden the utilization of diverse nanomaterials in pyroptosis-based antitumor immunotherapy, and facilitate advancements in clinical tumor therapy.

Efficient and Targeted siRNA Delivery to M2 Macrophages by Smart Polymer Blends for M1 Macrophage Repolarization as a Promising Strategy for Future Cancer Treatment

Cancer remains an issue on a global scale. It is estimated that nearly 10 million people succumbed to cancer worldwide in 2020. New treatment options are urgently needed. A promising approach is a conversion of tumor-promoting M2 tumor-associated macrophages (TAMs) as part of the tumor microenvironment to tumor-suppressive M1 TAMs by small interfering RNA (siRNA). In this work, we present a well-characterized polymeric nanocarrier system capable of targeting M2 TAMs by a ligand-receptor interaction. Therefore, we developed a blended PEI-based polymeric nanoparticle system conjugated with mannose, which is internalized after interaction with macrophage mannose receptors (MMRs), showing low cytotoxicity and negligible IL-6 activation. The PEI-PCL-PEI (5 kDa-5 kDa-5 kDa) and Man-PEG-PCL (2 kDa-2 kDa) blended siRNA delivery system was optimized for maximum targeting capability and efficient endosomal escape by evaluation of different polymer and N/P ratios. The nanoparticles were formulated by surface acoustic wave-assisted microfluidics, achieving a size of ∼80 nm and a zeta potential of approximately +10 mV. Special attention was given to the endosomal escape as the so-called bottleneck of RNA drug delivery. To estimate the endosomal escape capability of the nanocarrier system, we developed a prediction method by evaluating the particle stability via the inflection temperature. Our predictions were then verified in an in vitro setting by applying confocal microscopy. For cellular experiments, however, human THP-1 cells were polarized to M2 macrophages by cytokine treatment and validated through MMR expression. To show the efficiency of the nanoparticle system, GAPDH and IκBα knockdown was performed in the presence or absence of an MMR blocking excess of mannan. Cellular uptake, GAPDH knockdown, and NF-κB western blot confirmed efficient mannose targeting. Herein, we presented a well-characterized nanoparticle delivery system and a promising approach for targeting M2 macrophages by a mannose-MMR interaction.

PEI-Based Nanoparticles for Tumor Immunotherapy via In Situ Antigen-Capture Triggered by Photothermal Therapy

Activating a tumor antigen-specific immune response is key to the success of tumor immunotherapy and the development of personalized antitumor therapy. Nanocarriers can capture, enrich, and protect in situ produced tumor antigens due to immunogenic cell death (ICD), thus enhancing the tumor-specific immune response. Developing multifunctional nanocarriers that combine multiple antigen capturing mechanisms is crucial to the activation of tumor-specific immune responses. In this study, polyethylenimine (PEI) was employed as a main building block to construct a series of multifunctional indocyanine green (ICG)-loaded nanoparticles to capture antigens via multiple mechanisms: electrostatic interactions with PEI, hydrophobic interactions with the thermosensitive segment (POEGMA300), and covalent bonding with the pyridyl disulfide (PDS) groups, respectively. Their capacity of ICD induction, tumor antigen-capture, and antitumor immune responses were evaluated. Both the intrinsic toxicity of PEI and the ICG-mediated photothermal effect were responsible for inducing ICD. The positively charged PEI segment exhibited the best antigen-capturing ability via electrostatic interactions, promoted bone marrow-derived dendritic cell maturation and CD8+ T cell proliferation, and elicited antitumor immune responses in vivo. PDS groups bonded antigens covalently and significantly contributed to the suppression of distant tumor growth. Although the thermosensitive hydrophobic polymer segment did not contribute positively to antigen capture or tumor growth inhibition, NPs containing all of the functional modules prolonged the survival of tumor-bearing mice more than other treatments. This study provides more chemical insights into the design of polymer-based in situ nanovaccines against cancer.

Polymer-Based Nanoparticles as Drug Delivery Systems for Purines of Established Importance in Medicine

Many purine derivatives are active pharmaceutical ingredients of significant importance in the therapy of autoimmune diseases, cancers, and viral infections. In many cases, their medical use is limited due to unfavorable physicochemical and pharmacokinetic properties. These problems can be overcome by the preparation of the prodrugs of purines or by combining these compounds with nanoparticles. Herein, we aim to review the scientific progress and perspectives for polymer-based nanoparticles as drug delivery systems for purines. Polymeric nanoparticles turned out to have the potential to augment antiviral and antiproliferative effects of purine derivatives by specific binding to receptors (ASGR1-liver, macrophage mannose receptor), increase in drug retention (in eye, intestines, and vagina), and permeation (intranasal to brain delivery, PEPT1 transport of acyclovir). The most significant achievements of polymer-based nanoparticles as drug delivery systems for purines were found for tenofovir disoproxil in protection against HIV, for acyclovir against HSV, for 6-mercaptopurine in prolongation of mice ALL model life, as well as for 6-thioguanine for increased efficacy of adoptively transferred T cells. Moreover, nanocarriers were able to diminish the toxic effects of acyclovir, didanosine, cladribine, tenofovir, 6-mercaptopurine, and 6-thioguanine.

The Biocompatibility Analysis of Artificial Mucin-Like Glycopolymers

The ocular surface is covered by a tear film consisting of an aqueous/mucin phase and a superficial lipid layer. Mucins, highly O-glycosylated proteins, are responsible for lubrication and ocular surface protection. Due to contact lens wear or eye disorders, lubrication of the ocular surface can be affected. Artificial glycopolymers which mimic natural mucins could be efficient in ophthalmic therapy. Various neutral, positively, and negatively charged mucin-mimicking glycopolymers were synthesized (n = 11), cultured in different concentrations (1%, 0.1%, and 0.01% w/v) with human corneal epithelial cells (HCE), and analyzed by various cytotoxicity/viability, morphology, and immunohistochemistry (IHC) assays. Six of the eleven glycopolymers were selected for further analysis after cytotoxicity/viability assays. We showed that the six selected glycopolymers had no cytotoxic effect on HCE cells in the 0.01% w/v concentration. They did not negatively affect cell viability and displayed both morphology and characteristic markers as untreated control cells. These polymers could be used in the future as mucin-mimicking semi-synthetic materials for lubrication and protection of the ocular surface.

Polyethylenimine-based iron oxide nanoparticles enhance cisplatin toxicity in ovarian cancer cells in the presence of a static magnetic field

Background

Drug resistance in cancer cells is a major concern in chemotherapy. Cisplatin (CIS) is one of the most effective chemotherapeutics for ovarian cancer. Here, we investigated an experimental approach to increase CIS cytotoxicity and overcome cell resistance using nanoparticle-based combination treatments.

Methods

Polyethylenimine (PEI)-based magnetic iron oxide nanocomplexes were used for drug delivery in genetically matched CIS-resistant (A2780/CP) and -sensitive (A2780) ovarian cancer cells in the presence of a 20 mT static magnetic field. Magnetic nanoparticles (MNPs) were synthesized and bonded to PEI cationic polymers to form binary complexes (PM). The binding of CIS to the PM binary complexes resulted in the formation of ternary complexes PM/C (PEI-MNP/CIS) and PMC (PEI-MNP-CIS).

Results

CIS cytotoxicity increased at different concentrations of CIS and PEI in all binary and ternary delivery systems over time. Additionally, CIS induced cell cycle arrest in the S and G2/M phases and reactive oxygen species production in both cell lines. Ternary complexes were more effective than binary complexes at promoting apoptosis in the treated cells.

Conclusion

PEI-based magnetic nanocomplexes can be considered novel carriers for increasing CIS cytotoxicity and likely overcoming drug resistance of ovarian cancer cells.

Extracellular vesicle-embedded materials

Extracellular vesicles (EVs) are small membrane-bound vesicles released by cells. EVs are emerging as a promising class of therapeutic entity that could be adapted in formulation due to their lack of immunogenicity and targeting capabilities. EVs have been shown to have similar regenerative and therapeutic effects to their parental cells and also have potential in disease diagnosis. To improve the therapeutic potential of EVs, researchers have developed various strategies for modifying them, including genetic engineering and chemical modifications which have been examined to confer target specificity and prevent rapid clearance after systematic injection. Formulation efforts have focused on utilising hydrogel and nano-formulation strategies to increase the persistence of EV localisation in a specific tissue or organ. Researchers have also used biomaterials or bioscaffolds to deliver EVs directly to disease sites and prolong EV release and exposure. This review provides an in-depth examination of the material design of EV delivery systems, highlighting the impact of the material properties on the molecular interactions and the maintenance of EV stability and function. The various characteristics of materials designed to regulate the stability, release rate and biodistribution of EVs are described. Other aspects of material design, including modification methods to improve the targeting of EVs, are also discussed. This review aims to offer an understanding of the strategies for designing EV delivery systems, and how they can be formulated to make the transition from laboratory research to clinical use.

Cost-Effective Protein Production in CHO Cells Following Polyethylenimine-Mediated Gene Delivery Showcased by the Production and Crystallization of Antibody Fabs

Laboratory production of recombinant mammalian proteins, particularly antibodies, requires an expression pipeline assuring sufficient yield and correct folding with appropriate posttranslational modifications. Transient gene expression (TGE) in the suspension-adapted Chinese Hamster Ovary (CHO) cell lines has become the method of choice for this task. The antibodies can be secreted into the media, which facilitates subsequent purification, and can be glycosylated. However, in general, protein production in CHO cells is expensive and may provide variable outcomes, namely in laboratories without previous experience. While achievable yields may be influenced by the nucleotide sequence, there are other aspects of the process which offer space for optimization, like gene delivery method, cultivation process or expression plasmid design. Polyethylenimine (PEI)-mediated gene delivery is frequently employed as a low-cost alternative to liposome-based methods. In this work, we are proposing a TGE platform for universal medium-scale production of antibodies and other proteins in CHO cells, with a novel expression vector allowing fast and flexible cloning of new genes and secretion of translated proteins. The production cost has been further reduced using recyclable labware. Nine days after transfection, we routinely obtain milligrams of antibody Fabs or human lactoferrin in a 25 mL culture volume. Potential of the platform is established based on the production and crystallization of antibody Fabs and their complexes.

Salicylic acid functionalized zein for improving plant stress resistance and as a nanopesticide carrier with enhanced anti-photolysis ability

BACKGROUND

There is a serious global problem of salinization of arable land, causing large reduction in world food production. Use of plant hormones is an effective way to reduce damage caused to crops and salt stress.

RESULTS

In this study, PEI-EDA was modified with AM-zein and grafted with plant hormone SA (AM-zein-SA) and used as a nano-pesticide carrier to load emamectin benzoate (EB). The use of AM-zein-SA as a nano-pesticide carrier could reduce the damage caused by salt stress to crops. The structure of AM-zein-SA was characterized by FTIR, UV, fluorescence, Raman, and ¹H NMR spectroscopic techniques. AM-zein-SA could effectively improve the resistance of EB to ultraviolet radiations, resistance of cucumber to salt stress, and the absorption of EB by plants. The experimental results showed that AM-zein-SA could effectively improve the anti-UV property of EB by 0.88 fold. When treated with 120 mmol NaCl, the germination rate of cucumber seeds under salt stress increased by 0.93 fold in presence of 6.25 mg/L carrier concentration. The POD and SOD activities increased by 0.50 and 1.21 fold, whereas the content of MDA decreased by 0.23 fold. In conclusion, AM-zein-SA nano-pesticide carrier could be used to improve the salt resistance of crops and the adhesion of pesticides to leaves.

CONCLUSION

AM-zein-SA, without undergoing any changes in its insecticidal activity, could simultaneously improve the salt stress resistance and salt stress germination rate of cucumber, reduce growth inhibition due to stress under high-concentration salt, and had a good effect on crops. In addition, EB@AM-zein-SA obviously improved the upward transmission rate of EB, as compared with EB. In this study, SA was grafted onto zein-based nano-pesticide carrier, which provided a green strategy to control plant diseases, insects, and pests while reducing salt stress on crops in saline-alkali soil.

Combined Magnetic Hyperthermia and Photothermia with Polyelectrolyte/Gold-Coated Magnetic Nanorods

Magnetite nanorods (MNRs) are synthesized based on the use of hematite nanoparticles of the desired geometry and dimensions as templates. The nanorods are shown to be highly monodisperse, with a 5:1 axial ratio, and with a 275 nm long semiaxis. The MNRs are intended to be employed as magnetic hyperthermia and photothermia agents, and as drug vehicles. To achieve a better control of their photothermia response, the particles are coated with a layer of gold, after applying a branched polyethyleneimine (PEI, 2 kDa molecular weight) shell. Magnetic hyperthermia is performed by application of alternating magnetic fields with frequencies in the range 118-210 kHz and amplitudes up to 22 kA/m. Photothermia is carried out by subjecting the particles to a near-infrared (850 nm) laser, and three monochromatic lasers in the visible spectrum with wavelengths 480 nm, 505 nm, and 638 nm. Best results are obtained with the 505 nm laser, because of the proximity between this wavelength and that of the plasmon resonance. A so-called dual therapy is also tested, and the heating of the samples is found to be faster than with either method separately, so the strengths of the individual fields can be reduced. Due to toxicity concerns with PEI coatings, viability of human hepatoblastoma HepG2 cells was tested after contact with nanorod suspensions up to 500 µg/mL in concentration. It was found that the cell viability was indistinguishable from control systems, so the particles can be considered non-cytotoxic in vitro. Finally, the release of the antitumor drug doxorubicin is investigated for the first time in the presence of the two external fields, and of their combination, with a clear improvement in the rate of drug release in the latter case.

Plasmid-DNA Delivery by Covalently Functionalized PEI-SPIONs as a Potential ‘Magnetofection’ Agent

Nanoformulations for delivering nucleotides into cells as vaccinations as well as treatment of various diseases have recently gained great attention. Applying such formulations for a local treatment strategy, e.g., for cancer therapy, is still a challenge, for which improved delivery concepts are needed. Hence, this work focuses on the synthesis of superparamagnetic iron oxide nanoparticles (SPIONs) for a prospective “magnetofection” application. By functionalizing SPIONs with an active catechol ester (CafPFP), polyethyleneimine (PEI) was covalently bound to their surface while preserving the desired nanosized particle properties with a hydrodynamic size of 86 nm. When complexed with plasmid-DNA (pDNA) up to a weight ratio of 2.5% pDNA/Fe, no significant changes in particle properties were observed, while 95% of the added pDNA was strongly bound to the SPION surface. The transfection in A375-M cells for 48 h with low amounts (10 ng) of pDNA, which carried a green fluorescent protein (GFP) sequence, resulted in a transfection efficiency of 3.5%. This value was found to be almost 3× higher compared to Lipofectamine (1.2%) for such low pDNA amounts. The pDNA-SPION system did not show cytotoxic effects on cells for the tested particle concentrations and incubation times. Through the possibility of additional covalent functionalization of the SPION surface as well as the PEI layer, Caf-PEI-SPIONs might be a promising candidate as a magnetofection agent in future.

Biocompatible Nanocomposite Coatings Deposited via Layer-by-Layer Assembly for the Mechanical Reinforcement of Highly Porous Interconnected Tissue-Engineered Scaffolds

Tissue-engineered (TE) scaffolds provide an 'off-the-shelf' alternative to autograft procedures and can potentially address their associated complications and limitations. The properties of TE scaffolds do not always match the surrounding bone, often sacrificing porosity for improved compressive strength. Previously, the layer-by-layer (LbL) assembly technique was used to deposit nanoclay containing multilayers capable of improving the mechanical properties of open-cell structures without greatly affecting the porosity. However, the previous coatings studied contained poly(ethylenimine) (PEI), which is known to be cytotoxic due to the presence of amine groups, rendering it unsuitable for use in biomedical applications. In this work, poly(diallydimethylammonium chloride) (PDDA)- and chitosan (CHI)-based polyelectrolyte systems were investigated for the purpose of nanoclay addition as an alternative to PEI-based polyelectrolyte systems. Nanocomposite coatings comprising of PEI, poly(acrylic acid) (PAA), Na+ montmorillonite (NC), PDDA, CHI and sodium alginate (ALG) were fabricated. The coatings were deposited in the following manner: (PEI/PAA/PEI/NC), PEI-(PDDA/PAA/PDDA/NC) and (CHI/ALG/CHI/ALG). Results from scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analyses demonstrated that the nanoclay was successfully incorporated into each polymer bilayer system, creating a nanocomposite coating. Each coating was successful at tailoring the elastic modulus of the open-cell structures, with polyurethane foams exhibiting an increase from 0.15 ± 0.10 MPa when uncoated to 5.51 ± 0.40 MPa, 6.01 ± 0.36 MPa and 2.61 ± 0.41 MPa when coated with (PEI/PAA/PEI/NC), PEI-(PDDA/PAA/PDDA/NC) and (CHI/ALG/CHI/ALG), respectively. Several biological studies were conducted to determine the cytotoxicity of the coatings, including a resazurin reduction assay, scanning electron microscopy and fluorescent staining of the cell-seeded substrates. In this work, the PDDA-based system exhibited equivalent physical and mechanical properties to the PEI-based system and was significantly more biocompatible, making it a much more suitable alternative for biomaterial applications.

Quaternized Sodium Alginate-g-Ethyl-Oxazoline Copolymer Brushes and Their Supramolecular Networks via Hydrogen Bonding

Novel copolymer brushes of quaternized sodium alginate-g-(2-ethyl-2-oxazoline)_n are achieved by the grafting reaction of 2-ethyl-2-oxazoline (EOX) from benzyl bromide groups in quaternized sodium alginate (QSA). The average number of (EOX)_n structural units is mediated from 1 to 5 by changing the molar ratio of the EOX monomer to benzyl bromide side groups. There exists obvious microphase separation between the QSA backbone and (EOX)_n segments in the copolymer brushes due to their thermodynamic incompatibility. The strong hydrogen-bonding interaction between -OH groups in the backbone and N─C═O groups in (EOX)_n segments is helpful for the construction of reversible supramolecular networks. The copolymer brushes show low cytotoxicity for HeLa cells and good antibacterial properties for Escherichia coli and Staphylococcus aureus for the contribution of hydrophilic (EOX)_n segments and antibacterial activity of the quaternary ammonium. The antiprotein behavior of polymer surfaces is improved after rearrangement of (EOX)_n segments by tetrahydrofuran (THF) vapor induction. These copolymer brushes have good prospects for biomedical applications.

Mineralized vectors for gene therapy

There is an intense interest in developing materials for safe and effective delivery of polynucleotides using non-viral vectors. Mineralization of organic templates has long been used to produce complex materials with outstanding biocompatibility. However, a lack of control over mineral growth has limited the applicability of mineralized materials to a few in vitro applications. With better control over mineral growth and surface functionalization, mineralized vectors have advanced significantly in recent years. Here, we review the recent progress in chemical synthesis, physicochemical properties, and applications of mineralized materials in gene therapy, focusing on structure-function relationships. We contrast the classical understanding of the mineralization mechanism with recent ideas of mineralization. A brief introduction to gene delivery is summarized, followed by a detailed survey of current mineralized vectors. The vectors derived from calcium phosphate are articulated and compared to other minerals with unique features. Advanced mineral vectors derived from templated mineralization and specialty coatings are critically analyzed. Mineral systems beyond the co-precipitation are explored as more complex multicomponent systems. Finally, we conclude with a perspective on the future of mineralized vectors by carefully demarcating the boundaries of our knowledge and highlighting ambiguous areas in mineralized vectors. STATEMENT OF SIGNIFICANCE: Therapy by gene-based medicines is increasingly utilized to cure diseases that are not alleviated by conventional drug therapy. Gene medicines, however, rely on macromolecular nucleic acids that are too large and too hydrophilic for cellular uptake. Without tailored materials, they are not functional for therapy. One emerging class of nucleic acid delivery system is mineral-based materials. The fact that they can undergo controlled dissolution with minimal footprint in biological systems are making them attractive for clinical use, where safety is utmost importance. In this submission, we will review the emerging synthesis technology and the range of new generation minerals for use in gene medicines.

Nano dimensions/adjuvants in COVID-19 vaccines

A favorable outcome of the COVID-19 crisis might be achieved with massive vaccination. The proposed vaccines contain several different vaccine active principles (VAP), such as inactivated virus, antigen, mRNA, and DNA, which are associated with either standard adjuvants or nanomaterials (NM) such as liposomes in Moderna's and BioNTech/Pfizer's vaccines. COVID-19 vaccine adjuvants may be chosen among liposomes or other types of NM composed for example of graphene oxide, carbon nanotubes, micelles, exosomes, membrane vesicles, polymers, or metallic NM, taking inspiration from cancer nano-vaccines, whose adjuvants may share some of their properties with those of viral vaccines. The mechanisms of action of nano-adjuvants are based on the facilitation by NM of targeting certain regions of immune interest such as the mucus, lymph nodes, and zones of infection or blood irrigation, the possible modulation of the type of attachment of the VAP to NM, in particular VAP positioning on the NM external surface to favor VAP presentation to antigen presenting cells (APC) or VAP encapsulation within NM to prevent VAP degradation, and the possibility to adjust the nature of the immune response by tuning the physico-chemical properties of NM such as their size, surface charge, or composition. The use of NM as adjuvants or the presence of nano-dimensions in COVID-19 vaccines does not only have the potential to improve the vaccine benefit/risk ratio, but also to reduce the dose of vaccine necessary to reach full efficacy. It could therefore ease the overall spread of COVID-19 vaccines within a sufficiently large portion of the world population to exit the current crisis.

Simultaneous nanocarrier-mediated delivery of siRNAs and chemotherapeutic agents in cancer therapy and diagnosis: Recent advances

Recently, investigations have revealed that RNA interference (RNAi) has a remarkable potential to decrease cancer burden by downregulating genes. Among various RNAi molecules, small interfering RNA (siRNA) has been more attractive for this goal and is able to silence a target pathological path and promote the degradation of a certain mRNA, resulting in either gain or loss of function of proteins. Moreover, therapeutic siRNAs have exhibited low side effects compared to other therapeutic molecular candidates. Nevertheless, siRNA delivery has its own limitations including quick degradation in circulation, ineffective internalization and low passive uptake by cells, possible toxicity against off-target sites, and inducing unfavorable immune responses. Therefore, delivery tools must be able to specifically direct siRNAs to their target locations without inflicting detrimental effects on other sites. To conquer the mentioned problems, nanocarrier-mediated delivery of siRNAs, using inorganic nanoparticles (NPs), polymers, and lipids, has been developed as a biocompatible delivery approach. In this review, we have discussed recent advances in the siRNA delivery methods that employ nanoparticles, lipids, and polymers, as well as the inorganic-based co-delivery systems used to deliver siRNAs and anticancer agents to target cells.

Recent Advances in the Evaluation of Antimicrobial Materials for Resolution of Orthopedic Implant-Associated Infections In Vivo

While orthopedic implant-associated infections are rare, revision surgeries resulting from infections incur considerable healthcare costs and represent a substantial research area clinically, in academia, and in industry. In recent years, there have been numerous advances in the development of antimicrobial strategies for the prevention and treatment of orthopedic implant-associated infections which offer promise to improve the limitations of existing delivery systems through local and controlled release of antimicrobial agents. Prior to translation to in vivo orthopedic implant-associated infection models, the properties (e.g., degradation, antimicrobial activity, biocompatibility) of the antimicrobial materials can be evaluated in subcutaneous implant in vivo models. The antimicrobial materials are then incorporated into in vivo implant models to evaluate the efficacy of using the material to prevent or treat implant-associated infections. Recent technological advances such as 3D-printing, bacterial genomic sequencing, and real-time in vivo imaging of infection and inflammation have contributed to the development of preclinical implant-associated infection models that more effectively recapitulate the clinical presentation of infections and improve the evaluation of antimicrobial materials. This Review highlights the advantages and limitations of antimicrobial materials used in conjunction with orthopedic implants for the prevention and treatment of orthopedic implant-associated infections and discusses how these materials are evaluated in preclinical in vivo models. This analysis serves as a resource for biomaterial researchers in the selection of an appropriate orthopedic implant-associated infection preclinical model to evaluate novel antimicrobial materials.

A scoping review on the potentiality of PD-L1-inhibiting microRNAs in treating colorectal cancer: Toward single-cell sequencing-guided biocompatible-based delivery

Tumoral programmed cell death ligand 1 (PD-L1) has been implicated in the immune evasion and development of colorectal cancer. Although monoclonal immune checkpoint inhibitors can exclusively improve the prognosis of patients with microsatellite instability-high (MSI-H) and tumor mutational burden-high (TMB-H) colorectal cancer, specific tumor-suppressive microRNAs (miRs) can regulate multiple oncogenic pathways and inhibit the de novo expression of oncoproteins, like PD-L1, both in microsatellite stable (MSS) and MSI-H colorectal cancer cells. This scoping review aimed to discuss the currently available evidence regarding the therapeutic potentiality of PD-L1-inhibiting miRs for colorectal cancer. For this purpose, the Web of Science, Scopus, and PubMed databases were systematically searched to obtain peer-reviewed studies published before 17 March 2021. We have found that miR-191-5p, miR-382-3p, miR-148a-3p, miR-93-5p, miR-200a-3p, miR-200c-3p, miR-138-5p, miR-140-3p, and miR-15b-5p can inhibit tumoral PD-L1 in colorectal cancer cells. Besides inhibiting PD-L1, miR-140-3p, miR-382-3p, miR-148a-3p, miR-93-5p, miR-200a-3p, miR-200c-3p, miR-138-5p, and miR-15b-5p can substantially reduce tumor migration, inhibit tumor development, stimulate anti-tumoral immune responses, decrease tumor viability, and enhance the chemosensitivity of colorectal cancer cells regardless of the microsatellite state. Concerning the specific, effective, and safe delivery of these miRs, the single-cell sequencing-guided biocompatible-based delivery of these miRs can increase the specificity of miR delivery, decrease the toxicity of traditional nanoparticles, transform the immunosuppressive tumor microenvironment into the proinflammatory one, suppress tumor development, decrease tumor migration, and enhance the chemosensitivity of tumoral cells regardless of the microsatellite state.

Nanoscale Metal-Organic Frameworks: Recent developments in synthesis, modifications and bioimaging applications

Porous Metal-Organic Frameworks (MOFs) have emerged as eye-catching materials in recent years. They are widely used in numerous fields of chemistry thanks to their desirable properties. MOFs have a key role in the development of bioimaging platforms that are hopefully expected to effectually pave the way for accurate and selective detection and diagnosis of abnormalities. Recently, many types of MOFs have been employed for detection of RNA, DNA, enzyme activity and small-biomolecules, as well as for magnetic resonance imaging (MRI) and computed tomography (CT), which are valuable methods for clinical analysis. The optimal performance of the MOF in the bio-imaging field depends on the core structure, synthesis method and modifications processes. In this review, we have attempted to present crucial parameters for designing and achieving an efficient MOF as bioimaging platforms, and provide a roadmap for researchers in this field. Moreover, the influence of modifications/fractionalizations on MOFs performance has been thoroughly discussed and challenging problems have been extensively addressed. Consideration is mainly focused on the principal concepts and applications that have been achieved to modify and synthesize advanced MOFs for future applications.

Strategies in DNA vaccine for melanoma cancer

According to reports of the international agency for cancer on research, although malignant melanoma shows less prevalence than nonmelanoma skin cancers, it is the major cause of skin cancer mortality. Given that, the production of effective vaccines to control melanoma is eminently required. In this regard, DNA-based vaccines have been extensively investigated for melanoma therapy. DNA vaccines are capable of inducing both cellular and humoral branches of immune responses. These vaccines possess some valuable advantages such as lack of severe side effects and high stability compared to conventional vaccination methods. The ongoing studies are focused on novel strategies in the development of DNA vaccines encoding artificial polyepitope immunogens based on the multiple melanoma antigens, the inclusion of molecular adjuvants to increase the level of immune responses, and the improvement of delivery approaches. In this review, we have outlined the recent advances in the field of melanoma DNA vaccines and described their implications in clinical trials as a strong strategy in the prevention and control of melanoma.

Advanced mechanotherapy: Biotensegrity for governing metastatic tumor cell fate via modulating the extracellular matrix

Mechano-transduction is the procedure of mechanical stimulus translation via cells, among substrate shear flow, topography, and stiffness into a biochemical answer. TAZ and YAP are transcriptional coactivators which are recognized as relay proteins that promote mechano-transduction within the Hippo pathway. With regard to healthy cells in homeostasis, mechano-transduction regularly restricts proliferation, and TAZ and YAP are totally inactive. During cancer development a YAP/TAZ - stimulating positive response loop is formed between the growing tumor and the stiffening ECM. As tumor developments, local stromal and cancerous cells take advantage of mechanotransduction to enhance proliferation, induce their migratory into remote tissues, and promote chemotherapeutic resistance. As a newly progresses paradigm, nanoparticle-conjunctions (such as magnetic nanoparticles, and graphene derivatives nanoparticles) hold significant promises for remote regulation of cells and their relevant events at molecular scale. Despite outstanding developments in employing nanoparticles for drug targeting studies, the role of nanoparticles on cellular behaviors (proliferation, migration, and differentiation) has still required more evaluations in the field of mechanotherapy. In this paper, the in-depth contribution of mechano-transduction is discussed during tumor progression, and how these consequences can be evaluated in vitro.

Effects of Gene Delivery Approaches on Differentiation Potential and Gene Function of Mesenchymal Stem Cells

Introduction of a gene to mesenchymal stem cells (MSCs) is a well-known strategy to purposely manipulate the cell fate and further enhance therapeutic performance in cell-based therapy. Viral and chemical approaches for gene delivery interfere with differentiation potential. Although microinjection as a physical delivery method is commonly used for transfection, its influence on MSC cell fate is not fully understood. The current study aimed to evaluate the effects of four nonviral gene delivery methods on stem cell multi-potency. The four delivery methods are robotic microinjection, polyethylenimine (PEI), cationic liposome (cLipo), and calcium phosphate nanoparticles (CaP). Among the four methods, microinjection has exhibited the highest transfection efficiency of ~60%, while the three others showed lower efficiency of 10-25%. Robotic microinjection preserved fibroblast-like cell morphology, stress fibre intactness, and mature focal adhesion complex, while PEI caused severe cytotoxicity. No marked differentiation bias was observed after microinjection and cLipo treatment. By contrast, CaP-treated MSCs exhibited excessive osteogenesis, while PEI-treated MSCs showed excessive adipogenesis. Robotic microinjection system was used to inject the CRISPR/Cas9-encoding plasmid to knock out PPAR gene in MSCs, and the robotic microinjection did not interfere with PPAR function in differentiation commitment. Meanwhile, the bias in osteo-adipogenic differentiation exhibited in CaP and PEI-treated MSCs after PPAR knockout via chemical carriers. Our results indicate that gene delivery vehicles variously disturb MSCs differentiation and interfere with exogenous gene function. Our findings further suggest that robotic microinjection offers a promise of generating genetically modified MSCs without disrupting stem cell multi-potency and therapeutic gene function.

A size-shrinkable matrix metallopeptidase-2-sensitive delivery nanosystem improves the penetration of human programmed death-ligand 1 siRNA into lung-tumor spheroids

Given the maturation of small-interfering RNA (siRNA) techniques with nanotechnology, and because overexpression of human programmed death-ligand 1 (PD-L1) is crucial for T cell inactivation and immunosuppression of the tumor microenvironment, application of siRNA-PD-L1 has demonstrated positive progress in preclinical studies; however, the limited penetration of this compound into solid tumors remains a challenge. To decrease PD-L1 expression and increase the penetration efficacy of solid tumors, we synthesized a novel tumor-microenvironment-sensitive delivery polymer by conjugating hyaluronic acid (HA) to polyethyleneimine (PEI), with a matrix metalloproteinase-2 (MMP-2)-sensitive peptide acting as the linker (HA-P-PEI), for use in delivery of PD-L1-siRNA. Concurrent synthesis of a linker-less HA-PEI compound allowed confirmation that negatively charged siRNA can be complexed onto the positively charged HA-PEI and HA-P-PEI compounds to form nanoparticles with the same particle size and uniform distribution with serum stability. We found that the size of the HA-P-PEI/siRNA nanoparticles decreased to <10 nm upon addition of MMP-2, and that H1975 cells overexpressing CD44, PD-L1, and MMP-2 aided confirmation of the delivery efficacy of the HA-P-PEI/siRNA nanocomplexes. Additionally, the use of HA-P-PEI caused less cytotoxicity than PEI alone, demonstrating its high cellular uptake. Moreover, pretreatment with MMP-2 increased nanocomplex tumor permeability, and western blot showed that HA-P-PEI/PD-L1-siRNA efficiently downregulated the PD-L1 expression in H1975 cells. These results demonstrated a novel approach for siRNA delivery and tumor penetration for future clinical applications in cancer treatment.

Polymer-Based Drug-Free Therapeutics for Anticancer, Anti-Inflammatory, and Antibacterial Treatment

This paper summarizes the area of biomedicinal polymers, which serve as nanomedicines even though they do not contain any anticancer or antiinflammatory drugs. These polymer nanomedicines with unique design are in the literature highlighted as a novel class of therapeutics called "drug-free macromolecular therapeutics." Their therapeutic efficacy is based on the tailored multiple presentations of biologically active vectors, i.e., peptides, oligopeptides, or oligosaccharides. Thus, they enable, for example, to directly induce the apoptosis of malignant cells by the crosslinking of surface slowly internalizing receptors, or to deplete the efficacy of tumor-associated proteins. The precise biorecognition of natural binding motifs by multiple vectors on the polymer construct remains the crucial part in the designing of these drug-free nanomedicines. Here, the rationales, designs, synthetic approaches, and therapeutic potential of drug-free macromolecular therapeutics consisting of various active vectors are described in detail. Recent developments and achievements for namely B-cell lymphoma treatment, Gal-3-positive tumors, inflammative liver injury, and bacterial treatment are reviewed and highlighted. Finally, a possible future prospect within this highly exciting new field of nanomedicine research is presented.

Effect of Plasmid DNA Size on Chitosan or Polyethyleneimine Polyplexes Formulation

Gene therapy could be simply defined as a strategy for the introduction of a functional copy of desired genes in patients, to correct some specific mutation and potentially treat the respective disorder. However, this straightforward definition hides very complex processes related to the design and preparation of the therapeutic genes, as well as the development of suitable gene delivery systems. Within non-viral vectors, polymeric nanocarriers have offered an ideal platform to be applied as gene delivery systems. Concerning this, the main goal of the study was to do a systematic evaluation on the formulation of pDNA delivery systems based on the complexation of different sized plasmids with chitosan (CH) or polyethyleneimine (PEI) polymers to search for the best option regarding encapsulation efficiency, surface charge, size, and delivery ability. The cytotoxicity and the transfection efficiency of these systems were accessed and, for the best p53 encoding pDNA nanosystems, the ability to promote protein expression was also evaluated. Overall, it was showed that CH polyplexes are more efficient on transfection when compared with the PEI polyplexes, resulting in higher P53 protein expression. Cells transfected with CH/p53-pDNA polyplexes presented an increase of around 54.2% on P53 expression, while the transfection with the PEI/p53-pDNA polyplexes resulted in a 32% increase.

Immune Cell Membrane-Coated Biomimetic Nanoparticles for Targeted Cancer Therapy

Nanotechnology has provided great opportunities for managing neoplastic conditions at various levels, from preventive and diagnostic to therapeutic fields. However, when it comes to clinical application, nanoparticles (NPs) have some limitations in terms of biological stability, poor targeting, and rapid clearance from the body. Therefore, biomimetic approaches, utilizing immune cell membranes, are proposed to solve these issues. For example, macrophage or neutrophil cell membrane coated NPs are developed with the ability to interact with tumor tissue to suppress cancer progression and metastasis. The functionality of these particles largely depends on the surface proteins of the immune cells and their preserved function during membrane extraction and coating process on the NPs. Proteins on the outer surface of immune cells can render a wide range of activities to the NPs, including prolonged blood circulation, remarkable competency in recognizing antigens for enhanced targeting, better cellular interactions, gradual drug release, and reduced toxicity in vivo. In this review, nano-based systems coated with immune cells-derived membranous layers, their detailed production process, and the applicability of these biomimetic systems in cancer treatment are discussed. In addition, future perspectives and challenges for their clinical translation are also presented.

Fluorescent platinum nanoclusters as correlative light electron microscopy probes

Correlative Imaging (CI) visualizes a single sample/region of interest with two or more imaging modalities. The technique seeks to elucidate information that may not be discernible by using either of the constituent techniques in isolation. Correlative Light Electron Microscopy (CLEM) can be employed to streamline workflows, i.e., using fluorescent signals in the light microscope (LM) to inform the user of regions which should be imaged with electron microscopy (EM). The efficacy of correlative techniques requires high spatial resolution of signals from both imaging modalities. Ideally, a single point should originate from both the fluorescence and electron density. However, many of the ubiquitously used probes have a significant distance between their fluorescence and electron dense portions. Furthermore, electron dense metal nanoparticles used for EM visualization readily quench any proximal adjacent fluorophores. Therefore, accurate registration of both signals becomes difficult. Here we describe fluorescent nanoclusters in the context of a CLEM probe as they are composed of several atoms of a noble metal, in this case platinum, providing electron density. In addition, their structure confers them with fluorescence via a mechanism analogous to quantum dots. The electron dense core gives rise to the fluorescence which enables highly accurate signal registration between epifluorescence and electron imaging modalities. We provide a protocol for the synthesis of the nanoclusters with some additional techniques for their characterization and finally show how they can be used in a CLEM set up.

Layer by Layer Assembled Chitosan-Coated Gold Nanoparticles for Enhanced siRNA Delivery and Silencing

Delivery of small interfering RNA (siRNA) provides one of the most powerful strategies for downregulation of therapeutic targets. Despite the widely explored capabilities of this strategy, intracellular delivery is hindered by a lack of carriers that have high stability, low toxicity and high transfection efficiency. Here we propose a layer by layer (LBL) self-assembly method to fabricate chitosan-coated gold nanoparticles (CS-AuNPs) as a more stable and efficient siRNA delivery system. Direct reduction of HAuCl4 in the presence of chitosan led to the formation of positively charged CS-AuNPs, which were subsequently modified with a layer of siRNA cargo molecules and a final chitosan layer to protect the siRNA and to have a net positive charge for good interaction with cells. Cytotoxicity, uptake, and downregulation of enhanced Green Fluorescent Protein (eGFP) in H1299-eGFP lung epithelial cells indicated that LBL-CS-AuNPs provided excellent protection of siRNA against enzymatic degradation, ensured good uptake in cells by endocytosis, facilitated endosomal escape of siRNA, and improved the overall silencing effect in comparison with commercial transfection reagents Lipofectamine and jetPEI®. Therefore, this work shows that LBL assembled CS-AuNPs are promising nanocarriers for enhanced intracellular siRNA delivery and silencing.

Impact of Polyallylamine Hydrochloride on Gene Expression and Karyotypic Stability of Multidrug Resistant Transformed Cells

The synthetic polymer, polyallylamine hydrochloride (PAA), is found in a variety of applications in biotechnology and medicine. It is used in gene and siRNA transfer, to form microcapsules for targeted drug delivery to damaged and tumor cells. Conventional chemotherapy often does not kill all cancer cells and leads to multidrug resistance (MDR). Until recently, studies of the effects of PAA on cells have mainly focused on their morphological and genetic characteristics immediately or several hours after exposure to the polymer. The properties of the cell progeny which survived the sublethal effects of PAA and resumed their proliferation, were not monitored. The present study demonstrated that treatment of immortalized Chinese hamster cells CHLV-79 RJK sensitive (RJK) and resistant (RJKEB) to ethidium bromide (EB) with cytotoxic doses of PAA, selected cells with increased karyotypic instability, were accompanied by changes in the expression of p53 genes c-fos, topo2-α, hsp90, hsc70. These changes did not contribute to the progression of MDR, accompanied by the increased sensitivity of these cells to the toxic effects of doxorubicin (DOX). Our results showed that PAA does not increase the oncogenic potential of immortalized cells and confirmed that it can be used for intracellular drug delivery for anticancer therapy.

Recent developments in targeting genes and pathways by RNAi-based approaches in colorectal cancer

A wide spectrum of genetic and epigenetic variations together with environmental factors has made colorectal cancer (CRC), which involves the colon and rectum, a challenging and heterogeneous cancer. CRC cannot be effectively overcomed by common conventional therapies including surgery, chemotherapy, targeted therapy, and hormone replacement which highlights the need for a rational design of novel anticancer therapy. Accumulating evidence indicates that RNA interference (RNAi) could be an important avenue to generate great therapeutic efficacy for CRC by targeting genes that are responsible for the viability, cell cycle, proliferation, apoptosis, differentiation, metastasis, and invasion of CRC cells. In this review, we underline the documented benefits of small interfering RNAs and short hairpin RNAs to target genes and signaling pathways related to CRC tumorigenesis. We address the synergistic effects of RNAi-mediated gene knockdown and inhibitors/chemotherapy agents to increase the sensitivity of CRC cells to common therapies. Finally, this review points new delivery systems/materials for improving the cellular uptake efficiency and reducing off-target effects of RNAi.

Cutting-edge progress and challenges in stimuli responsive hydrogel microenvironment for success in tissue engineering today

The field of tissue engineering has numerous potential for modified therapeutic results and has been inspired by enhancements in bioengineering at the recent decades. The techniques of regenerating tissues and assembling functional paradigms that are responsible for repairing, maintaining, and revitalizing lost organs and tissues have affected the entire spectrum of health care studies. Strategies to combine bioactive molecules, biocompatible materials and cells are important for progressing the renewal of damaged tissues. Hydrogels have been utilized as one of the most popular cell substrate/carrier in tissue engineering since previous decades, respect to their potential to retain a 3D structure, to protect the embedded cells, and to mimic the native ECM. The hydrophilic nature of hydrogels can provide an ideal milieu for cell viability and structure, which simulate the native tissues. Hydrogel systems have been applied as a favorable matrix for growth factor delivery and cell immobilization. This study reviews a brief explanation of the structure, characters, applications, fabrication methods, and future outlooks of stimuli responsive hydrogels in tissue engineering and, in particular, 3D bioprinting.

Recent progress in the design of DNA vaccines against tuberculosis

Current tuberculosis (TB) vaccines have some disadvantages and many efforts have been undertaken to produce effective TB vaccines. As a result of their advantages, DNA vaccines are promising future vaccine candidates. This review focuses on the design and delivery of novel DNA-based vaccines against TB.

Selective Control of Cell Activity with Hydrophilic Polymer-Covered Cationic Nanoparticles

Cationic polymers exhibit high cytotoxicity via strong interaction with cell membranes. To reduce cell membrane damage, a hydrophilic polymer is introduced to the cationic nanoparticle surface. The hydrophilic polymer coating of cationic nanoparticles resulted in a nearly neutral nanoparticle. These particles are applied to mouse fibroblast (3T3) and human cervical adenocarcinoma (Hela) cells. Interestingly, nanoparticles with a long cationic segment decrease cell activity regardless of cell type, while those with a short segment only affect 3T3 cell activity at lower concentrations less than 500 µg mL^-1 . Most nanoparticles are located inside 3T3 cells but on the cell membrane of Hela cells. The short cationic nanoparticle shows negligible cell membrane damage despite its high accumulation on Hela cell membranes. Cell activity changed by hydrophilic polymer-coated cationic nanoparticles is caused by incorporated nanoparticle accumulation in the cells, not cell membrane damage. To suppress the cytotoxicity from the cationic polymer, cationic nanoparticle needs to completely cover with hydrophilic polymer so as not to exhibit the cationic effect and applies to cell with low concentrations to reduce the nonselective cytotoxicity from the cationic polymer.

Growing Patterned, Cross-linked Nanoscale Polymer Films from Organic and Inorganic Surfaces Using Ring-Opening Metathesis Polymerization

The ability to modify substrates with thin polymer films allows for the tailoring of surface properties, and through combination of patterning finds use in a large variety of applications such as electronics and lab-on-chip devices. Although many techniques can be used to afford polymer-modified surfaces such as surface-initiated polymerization or layer-by-layer methodologies, their stability in a wide range of environments as well as their ability to target specific chemistry are critical factors to enable their successful application. In this paper, we report a facile technique in creating nanoscale polymer thin films using solid-state continuous assembly of polymers via ring-opening metathesis polymerization (ssCAP_ROMP) directly from surfaces functionalized through silanization. Using a polymeric precursor that includes norbornene moieties, a highly dense cross-linked network of polymer can be grown in a bottom-up fashion to afford thin films from an olefin-terminated silanized planar surface. Such nanotechnology affords films retaining the desirable qualities of previously reported methods while, at the same time, being covalently bound to the substrate: they are virtually pinhole free and can be reinitiated multiple times. By combining this process with microcontact printing, patterned films can be created by either the patterned deposition of a catalyst or by controlling the surface silanization chemistry and placement of olefin-terminated and nonreactive silanes. Additionally, patterned ssCAP_ROMP films were grown from SU-8 by selectively functionalizing the surface through masking and lift-off processes after the silanization step, thereby spatially controlling the surface-initiation, and subsequent polymer film formation. These patterned films expand the capabilities of the CAP_ROMP process and offer advantages over other film formation techniques in processes where patterned substrates and modified but robust surface chemistries are utilized.