Cytotoxicity Experiments Research Articles

Synthesis, characterization, and antibacterial activity of chitosan-chelated silver nanoparticles

Bacterial infections pose a significant threat to human health and safety, necessitating the urgent resolution of the problem through the development and implementation of highly effective antibacterial agents. However, the emergence of multidrug-resistant bacteria has diminished the satisfactory effectiveness of antibacterial treatments. To overcome this obstacle, we developed effective antibacterial agents by chemical reduction for inhibiting bacterial proliferation and inducing membrane damage. Specifically, four different types of chitosan/Ag nanoparticle (CS-AgNPs-i) (i-1, 2, 3, 4) complexes were synthesized by varying the quantity of chitosan added during the synthesis process. We found that the amount of CS does not affect the morphology and size of CS-AgNPs-i, which remained at approximately 20 nm and all CS-AgNPs were mostly spherical. The zeta potential measurements indicated that the surface of CS-AgNPs carries a positive charge. Notably, elevating the chitosan concentration led to a more pronounced antibacterial impact, particularly evident in its interaction with the peptidoglycan layer on the bacterial surface. Our experimental results undeniably establish the potent antibacterial efficacy of CS-AgNPs against both Escherichia coli and Staphylococcus aureus. Employing live/dead bacterial staining, we reveal the marked capability of CS-AgNPs to effectively hinder bacterial proliferation. Furthermore, our experimental investigations revealed that CS-AgNPs possess broad-spectrum antimicrobial activity. The results of in vitro cytotoxicity experiments substantiated the high biocompatibility of CS-AgNPs with elevated chitosan loading. The study provides valuable insights into the development of nano-antibacterial agents that exhibit significant potential as a substitute to replace traditional antibiotics for medical applications.

Dual-functional smart indicator for direct monitoring fruit freshness

Innovative smart packaging systems that inhibit bacterial growth and monitor food quality change are urgently needed in food industry. A dual-functional polyvinyl alcohol/polyethyleneimine/methylene blue (PVA/PEI/MB) nanofiber film was prepared for inhibiting bacterial growth and monitoring freshness of fruit. The nanofibers exhibited excellent mechanical property, breathability, water resistance and biocompatibility as characterized by the tensile test, air permeability test, water contact angle and cytotoxicity experiment. In vitro antibacterial experiment showed that the nanofibers had strong antibacterial activities against Escherichia coli and Staphylococcus aureus, and the antibacterial activities were improved under light irradiation. Nanofibers showed color variation from blue to colorless under bacterial infection in a range of 101–1010 CFU/mL, which can be used to detect the freshness of fresh-cut fruit. Effectiveness of nanofibers for freshness keeping and monitoring was confirmed via fruit tests, which suggests that the dual-functional nanofibers could potentially be used in food packaging.

Preparation and properties of silica/hydroxyapatite whiskers porous ceramics scaffold

To investigate the preparation and properties of the novel silica (SiO 2)/hydroxyapatite (HAP) whiskers porous ceramics scaffold. The HAP whiskers were modified by the SiO 2 microspheres using the Stöber method. Three types of SiO 2/HAP whiskers were fabricated under different factors (for the No.1 samples, the content of tetraethoxysilane, stirring time, calcination temperature, and soaking time were 10 mL, 12 hours, 560℃, and 0.5 hours, respectively; and in the No.2 samples, those were 15 mL, 24 hours, 650℃, and 2 hours, respectively; while those in the No.3 samples were 20 mL, 48 hours, 750℃, and 4 hours, respectively). The phase and morphology of the self-made HAP whisker and 3 types of SiO 2/HAP whiskers were detected by the X-ray diffraction analysis and scanning electron microscopy. Taken the self-made HAP whisker and 3 types of SiO 2/HAP whiskers as raw materials, various porous ceramic materials were prepared using the mechanical foaming method combined with extrusion molding method, and the low-temperature heat treatment. The pore structure of porous ceramics was observed by scanning electron microscopy. Its porosity and pore size distribution were measured. And further the axial compressive strength was measured, and the biodegradability was detected by simulated body fluid. Cell counting kit 8 method was used to conduct cytotoxicity experiments on the extract of porous ceramics. The SiO 2 microspheres modified HAP whiskers and its porous ceramic materials were prepared successfully, respectively. In the SiO 2/HAP whiskers, the amorphous SiO 2 microspheres with a diameter of 200 nm, uniform distribution and good adhesion were attached to the surface of the whiskers, and the number of microspheres was controllable. The apparent porosity of the porous ceramic scaffold was about 78%, and its pore structure was composed of neatly arranged longitudinal through-holes and a large number of micro/nano through-holes. Compared with HAP whisker porous ceramic, the axial compressive strength of the SiO 2/HAP whisker porous ceramics could reach 1.0 MPa, which increased the strength by nearly 4 times. Among them, the axial compressive strength of the No.2 SiO 2/HAP whisker porous ceramic was the highest. The SiO 2 microspheres attached to the surface of the whiskers could provide sites for the deposition of apatite. With the content of SiO 2 microspheres increased, the deposition rate of apatite accelerated. The cytotoxicity level of the prepared porous ceramics ranged from 0 to 1, without cytotoxicity. SiO 2/HAP whisker porous ceramics have good biological activity, high porosity, three-dimensional complex pore structure, good axial compressive strength, and no cytotoxicity, which make it a promising scaffold material for bone tissue engineering.

Fabrication of novel printable artificial bone composites used as cartilage scaffolds by an additive manufacturing process

AbstractPolylactic acid (PLA), a biodegradable polymer, has become a major raw material in the field of 3D printing. However, some defects such as high brittleness and average bioactivity limit its application. In this study, a novel 3D printing composite of animal bone powder/polyethylene glycol/polylactic acid was prepared and investigated. The structures and properties of bHA/PEG/PLA composites were compared with commercial micron‐sized hydroxyapatite (mHA) and nano hydroxyapatite (nHA) composites. The study results show that the bHA has the same chemical structure as mHA and nHA, but its average particle size is 390 nm, which is quite different from mHA and nHA. When the PEG content is 14%, the toughness of the PEG/PLA blends is good, and its elongation at break reaches 96.23%. The bending strength, tensile strength, and elongation at break of bHA/PEG/PLA composites reach 25.1 MPa, 16.3 MPa, and 11.32%, respectively, which are all higher than those of mHA/PEG/PLA and similar to those of nHA/PEG/PLA. The bHA/PEG/PLA biological scaffolds prepared by 3D printing show good biocompatibility in cytotoxicity experiments and have good application prospects in bone tissue engineering.

A pH-responsive bi-MIL-88B MOF coated with folic acid-conjugated chitosan as a promising nanocarrier for targeted drug delivery of 5-Fluorouracil.

Cancer has remained one of the leading causes of death worldwide, with a lack of effective treatment. The intrinsic shortcomings of conventional therapeutics regarding tumor specificity and non-specific toxicity prompt us to look for alternative therapeutics to mitigate these limitations. In this regard, we developed multifunctional bimetallic (FeCo) bi-MIL-88B-FC MOFs modified with folic acid-conjugated chitosan (FC) as drug delivery systems (DDS) for targeted delivery of 5-Fluorouracil (5-FU). The bi-MIL-88B nanocarriers were characterized through various techniques, including powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Interestingly, 5-FU@bi-MIL-88B-FC showed slower release of 5-FU due to a gated effect phenomenon endowed by FC surface coating compared to un-modified 5-FU@bi-MIL-88B. The pH-responsive drug release was observed, with 58% of the loaded 5-FU released in cancer cells mimicking pH (5.2) compared to only 24.9% released under physiological pH (5.4). The in vitro cytotoxicity and cellular internalization experiments revealed the superiority of 5-FU@bi-MIL-88B-FC as a highly potent targeted DDS against folate receptor (FR) positive SW480 cancer cells. Moreover, due to the presence of Fe and Co in the structure, bi-MIL-88B exhibited peroxidase-like activity for chemodynamic therapy. Based on the results, 5-FU@bi-MIL-88B-FC could serve as promising candidate for smart DDS by sustained drug release and selective targeting.

Hydro Electroactive Janus Micro/Nano Fiber Dressing with Exudate Management Ability for Wound Healing

Exudate management and bioelectric signals are critical to promoting wound healing. In this study, the thermoplastic polyurethane (TPU) nanofiber is directly electrospun on the cotton microfibers (Cotton) to prepare a Janus dressing (TPU/Cotton), which can unidirectionally drain the excess exudate. Then, Ag/Zn dot electrodes are deposited on the TPU layer, which can produce an electric field penetrating the wound when activated by wound exudate. The hydro‐activated Ag/Zn's electrical stimulation (ES) can promote the migration of fibroblast cells and shows excellent antibacterial activity against E. coli and S. aureus. Furthermore, in vivo experiments show that the exudate management coupled with ES accelerated wound healing at multiple stages by promoting re‐epithelization, collagen deposition, and vascularization. Moreover, the Ag/Zn@TPU/Cotton dressing shows excellent biocompatibility in the vitro cytotoxicity experiments. These findings may shed some light on developing the next generation of wound dressings with self‐activated electrical stimulation and exudate management.

A multi-functional double cross-linked chitosan hydrogel with tunable mechanical and antibacterial properties for skin wound dressing

Chitosan hydrogels with essential antibacterial properties and biocompatibility have great potential in tissue engineering and regeneration medicine. However, pure chitosan hydrogel could be limited by insufficient mechanical properties. In this work, we designed a multi-functional chitosan hydrogel based on the combination of chitosan methacrylate (CTSMA) and sulfhydrated chitosan (CTSSH), which is cross-linked simultaneously by free-radical polymerization reaction and Thiol-ene reaction. The CTSMA/CTSSH (CMS) hydrogels displayed superior tissue adhesive and mechanical properties when compared to pure CTSMA hydrogel. Additionally, the resulting hydrogels exhibited potent antimicrobial effects against both E. coli and S. aureus. Besides, the CMS hydrogels exhibited good biocompatibility as demonstrated by cytotoxicity and cell proliferation experiments using fibroblasts cells (L929) and adipose-derived stem cells (ADSCs). In vivo experiment, the repairing effect of hydrogels on full-thickness skin defect model in rats was studied. Histological and immunohistochemical staining results showed that CMS hydrogels promoted angiogenesis, dermal repair and epidermal regeneration. Overall, the study highlights the potential of the CMS hydrogels as a promising biomaterial in wound healing applications.

Poly(2-n-propyl-2-oxazoline)/tannic acid nanocapsules with in-situ synthesized gold nanorods for cancer theranostics

The concept of hollow polymeric capsules fabricated with thermoresponsive polymers has revealed immense possibilities in the field of nanomedicine due to their tunable temperature and pH responsiveness caused by lower critical solution temperature (LCST) behavior. Herein, we report a new methodology to in-situ synthesize gold nanorods (AuNRs) within the pores of mesoporous silica nanoparticles (NPs) by trapping gold seed crystals and growing them into NRs in the presence of a weak reducing agent. The mesoporous silica NPs with incorporated NRs, i.e., modified silica NPs (SiO2-NRs) were used as sacrificial template for the fabrication of hollow polymeric multilayer capsules via layer-by-layer (LbL) assembly using poly(2-n-propyl-2-oxazoline) (PnPrOx) and tannic acid (TA) as layer components. The NRs of 25 ± 5 nm in size were uniformly distributed in the interior structure of PnPrOx/TA nanocapsules. The photo-thermal conversion efficiency of the PnPrOx/TA nanocapsules was found to be 47.5%. The release of encapsulated doxorubicin was found to be 55%, which increased to 68% when the incubation time was increased from 1 to 2 h. An on-demand burst release of 56% of the drug occurred within 2 min of NIR light exposure, and it reached 72% within 30 min, which inflicted major damage to cancer cells. Notably, the capsule suspension temperature increase from room temperature to 47 °C under laser light exposure, which is not only playing a key role in rupturing the capsules to enhance the drug release but also induces a hyperthermia effect in the tumor environment. Further, the in-vitro cytotoxicity experiments with human epithelial HEp-2 cells and fibrosarcoma HT1080 cells revealed an enhanced anti-cancer activity due to a synergistic chemo-photothermal effect. Hence, the proposed nanocapsule system can provide a unique, cheap, and efficient way of fabricating cancer theranostics for in-vivo applications.

In Vitro, Oral Acute, and Repeated 28-Day Oral Dose Toxicity of a Mixed-Valence Polyoxovanadate Cluster.

Polyoxovanadates (POV) are a subgroup of polyoxometalates (POM), which are nanosized clusters with reported biological activities. This manuscript describes the first toxicity evaluation of a mixed-valence polyoxovanadate, pentadecavanadate, (Me4N)6[V15O36Cl], abbreviated as V15. Cytotoxicity experiments using peripheral blood mononuclear cells (PBMC), larvae of Artemia salina Leach, and in vivo oral acute and repeated 28-day doses in mice was carried out. The LC50 values in PBMC cells and A. salina were 17.5 ± 5.8 μmol L-1, and 17.9 µg L-1, respectively, which indicates high cytotoxic activity. The toxicity in mice was not observed upon acute exposure in a single dose, however, the V15 repeated 28-day oral administration demonstrated high toxicity using 25 mg/kg, 50 mg/kg and, 300 mg/kg doses. The biochemical and hematological analyses during the 28-day administration of V15 showed significant alteration of the metabolic parameters related to the kidney and liver, suggesting moderate toxicity. The V15 toxicity was attributed to the oxidative stress and lipid peroxidation, once thiobarbituric acid (TBAR) levels significantly increased in both males and females treated with high doses of the POV and also in males treated with a lower dose of the POV. This is the first study reporting a treatment-related mortality in animals acutely administrated with a mixed-valence POV, contrasting with the well-known, less toxic decavanadate. These results document the toxicity of this mixed-valence POV, which may not be suitable for biomedical applications.

Protective effects of Aureobasidium pullulans lysate on UV-damaged human skin fibroblasts and HaCaT cells

BackgroundAureobasidium pullulans (A. pullulans) has a wide range of applications. Ultraviolet (UV) rays from the sun can cause skin photoaging. In order to explore the protective effect and application potential of A. pullulans lysate on UV-damaged human skin fibroblasts (HSF) and HaCaT Cells, this study investigates the anti-aging and anti-inflammatory effects of A. pullulans lysate as well as the mechanism of anti-oxidative stress at the cellular and molecular levels through cytotoxicity experiments, enzyme-linked immunosorbent assays (ELISA), and real-time quantitative PCR (RT-qPCR).ResultsThe experimental results have shown that the A. pullulans lysate can effectively reduce the loss of extracellular matrix components (EMC), such as collagen and hyaluronic acid (HA). It is also capable of scavenging excess reactive oxygen species (ROS) from the body, thereby increasing the activity of catalase, decreasing the overexpression of intracellular matrix metalloproteinases (MMPs), enhancing the gene expression of metalloproteinase inhibitors (TIMPs), and decreasing the level of inflammatory factors, reducing UV-induced apoptosis of HaCaT cells. Meanwhile, oxidative stress homeostasis is also regulated through the Nrf2/Keap1 and MAPK signaling pathways.ConclusionsThis study shows that the A. pullulans lysate has the potential to resist photoaging.Graphical

Improvement of the Effectiveness of HER2+ Cancer Therapy by Use of Doxorubicin and Trastuzumab Modified Radioactive Gold Nanoparticles.

In the present article, we describe a multimodal radiobioconjugate that contains a chemotherapeutic agent (doxorubicin, DOX), a β-emitter (198Au), and a guiding vector (trastuzumab, Tmab) for targeted therapy of cancers overexpressing HER2 receptors. To achieve this goal, radioactive gold nanoparticles (198AuNPs) with a mean diameter of 30 nm were synthesized and coated with a poly(ethylene glycol) (PEG) linker conjugated to DOX and monoclonal antibody (Tmab) via peptide bond formation. In vitro experiments demonstrated a high affinity of the radiobioconjugate to HER2 receptors and cell internalization. Cytotoxicity experiments performed using the MTS assay showed a significant decrease in the viability of SKOV-3 cells. A synergistic cytotoxic effect due to the simultaneous presence of DOX and 198Au was revealed after 48 h of treatment with 2.5 MBq/mL. Flow cytometry analysis indicated that DOX-198AuNPs-Tmab mainly induced cell cycle arrest in the G2/M phase and late apoptosis. Dose-dependent additive and synergistic effects of the radiobioconjugate were also shown in spheroid models. Ex vivo biodistribution experiments were performed in SKOV-3 tumor-bearing mice, investigating different distributions of the 198AuNPs-DOX and DOX-198AuNPs-Tmab after intravenous (i.v.) and intratumoral (i.t.) administration. Finally, in vivo therapeutic efficacy studies on the same animal model demonstrated very promising results, as they showed a significant tumor growth arrest up to 28 days following a single intratumoral injection of 10 MBq. Therefore, the proposed multimodal radiobioconjugate shows great potential for the local treatment of HER2+ cancers.

Constructing ROS-Responsive Supramolecular Gel with Innate Antibacterial Properties.

Bacterial infections, especially antibiotic-resistant bacterial infections, pose a significant threat to human health. Supramolecular gel with innate antibacterial properties is an advanced material for the treatment of bacterial infections, which have attracted great attention. Herein, a reactive oxygen species (ROS)-responsive innate antibacterial supramolecular gel is developed by a bottom-up approach based on phenylalanine and hydrazide with innate antibacterial properties. The structure of gelators and intermediate products was characterized by proton nuclear magnetic resonance (1H NMR) and a high-resolution mass spectrum (HRMS). The results of 1H NMR and the Fourier transform infrared spectrum (FT-IR) experiment disclosed that hydrogen bonding and the π-π stacking force are the important self-assembly driving forces of gelators. The microstructure and mechanical properties of gel were studied by Scanning electron microscope (SEM) and Rheometer, respectively. An in vitro degradation experiment proved that the gelator has ROS-responsive degradation properties. The in vitro drug release experiment further manifested that antibiotic-loaded gel has ROS-responsive drug-release performances. An in vitro cytotoxicity experiment showed that the supramolecular gel has good biocompatibility and could promote cell proliferation. The in vitro antibacterial experiment proved that the supramolecular gel has excellent inherent antibacterial properties, and the antibacterial rate against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was 98.6% and 99.1%, respectively. The ROS-responsive supramolecular gel as a novel antibacterial agent has great application prospects in treating antibiotic-resistant bacterial-infected wounds and preventing the development of bacterial resistance.

Photocuring and Gelatin-Based Antibacterial Hydrogel for Skin Care.

The development of moisturizing, antibacterial, and biocompatible multifunctional hydrogels is essential to protect skin and promote skin defects recovery. Gelatin has admired potential to be applied for skin care as a hydrogel in virtue of its hydrophilic biocompatible and biodegradable properties. In this study, triclosan-grafted gelatin and photo-cross-linkable methacrylated gelatin were synthesized and then combined to construct the semi-interpenetrating network and antibacterial hydrogels with the aid of a visible blue light. The antimicrobial test demonstrated that the resulting hydrogel obtained excellent inactivation capacity against E. coli, S. aureus, T. rubrum, and C. albicans with sterilizing rates of 99.998%, 99.998%, 99.19%, and 99.64%, respectively. In addition, the cytotoxicity, hemolysis, skin irritation, and rat skin wound healing experiments proved the good biocompatibility of the hydrogel. Therefore, this investigation sheds light on the development of multifunctional hydrogels in skin care.

Synthesis and insecticidal activity of cysteine-free conopeptides from Conus betulinus

The cone snail Conus betulinus is a vermivorous species that is widely distributed in the South China Sea. Its crude venom contains various peptides used to prey on marine worms. In previous studies, a systematic analysis of the peptide toxin sequences from C. betulinus was carried out using a multiomics technique. In this study, 10 cysteine-free peptides that may possess insecticidal activity were selected from a previously constructed conopeptide library of C. betulinus using the CPY-Fe conopeptide as a template. These conopeptides were prepared by solid-phase peptide synthesis (SPPS), then characterized by the reverse-phase high performance liquid chromatography (HPLC) and mass spectrometry. Insect cytotoxicity and injection experiments revealed that these cysteine-free peptides exerted favorable insecticidal effects, and two of them (Bt010 and Bt016) exhibited high insecticidal efficacy with LD50 of 9.07 nM and 10.93 nM, respectively. In addition, the 3D structures of these peptides were predicted by homology modeling, and a phylogenetic tree was constructed based on the nucleotide data of conopeptides to analyze the relationships among structures, functions, and evolution. A preliminary mechanism for the insecticidal activity of the cysteine-free conopeptides was predicted by molecular docking. To the best of our knowledge, this is the first study to report the insecticidal activity of cysteine-free conopeptides derived from Conus betulinus, signaling that they could potentially be developed into bioinsecticides with desirable properties such as easy preparation, low cost, and high potency.

Metal–organic framework- and graphene quantum dot-incorporated nanofibers as dual stimuli-responsive platforms for day/night antibacterial bio-protection

Development of advanced antibacterial nanomaterials is important to prevent pathogenic microbial contamination and achieve bioprotection. Herein, we developed dual-stimuli-responsive nanoplatforms with efficient antibacterial activity based on electrospun polycaprolactone/hydroxypropyltrimethylammonium chloride chitosan (PQ) nanofiber membranes (NFMs) incorporated with naringenin-loaded zeolitic imidazolate framework-8 (NAR@ZIF-8) and graphene quantum dots (GQDs). These NFM nanoplatforms could simultaneously be used as “smart” pH-responsive controlled-release and photocatalytic systems. NAR was encapsulated in the microporous structure of the ZIF-8 channel, with a loading capacity of 22.57%. NAR@ZIF-8- and GQD-incorporated PQ (PQZG) nanofibers exhibited enhanced thermal stability and mechanical properties. The release kinetics and microstructure of the nanocarriers demonstrated that the acid-sensitive cleavable crystal structure of ZIF-8 resulted in the pH-responsive release of NAR from PQZG NFMs. Moreover, the presence of GQDs significantly enhanced the photoinduced reactive oxygen species (ROS) generation by NFMs. pH-triggered NAR release and photoinduced ROS generation improved the antibacterial efficacy of PQZG NFMs, forming the synergetic chemical-photodynamic strategies of the dual stimuli-responsive nanoplatforms. Additionally, cytotoxicity experiments revealed that the PQZG NFMs were non-toxic and had good biocompatibility. Therefore, the designed composite nanomaterials combined with the two antibacterial strategies can aid in the development of biosafe nanofibrous membranes for antibacterial or multifunctional bio-protection.

Biomass derived nitrogen-doped activated carbon and novel biocompatible gel electrolytes for solid-state supercapacitor applications

The development of biocompatible energy storage technologies is crucial for powering implantable devices in the health sector. In the current study, red beetroot (Beta vulgaris L.) is used as a biomass precursor to synthesize microporous nitrogen-doped activated carbon (NACBR). The resulting carbon structure has an improved specific surface area (SSA) of 2200 m2g−1 and a hierarchical sponge-like porosity. In-vitro cytotoxic experiments support the biocompatibility of the as-synthesized carbon. It is known that N-doping increases surface wettability and conductivity, which enhances the electrode material's specific capacitance. According to electrochemical studies, in 1 M Na2SO4 electrolyte, the NACBR electrode has the highest specific capacitance of 492 F g−1 at 1 A g−1 current density. Furthermore, Na2SO4, phosphate-buffered saline (PBS), and simulated bodily fluid (SBF) gel-electrolytes are used to fabricate and test biocompatible solid-state supercapacitor devices. The goal of this research is to construct and test biocompatible supercapacitors that could power implantable devices.

PH-triggered “PEG” sheddable and folic acid-targeted nanoparticles for docetaxel delivery in breast cancer treatment

Multifunctional nanoparticles have attracted significant attentions for oncology and cancer treatment. In fact, they could address critical point for tumour treatment by creating a stimuli-responsive targeted drug delivery system that can exist stably in the systemic circulation, efficiently penetrate the tumour tissue, and then accumulate in tumour cells in large quantities. A novel stepwise pH-responsive multifunctional nanoparticles (FPDPCNPs/DTX) for targeted delivery of the antitumour drug docetaxel (DTX) is prepared by coating a tumour acidity-sensitive “sheddable” FA modified β-carboxylic amide functionalized PEG layer (folic acid-polyethylene glycol-2,3-dimethylmaleic anhydride, FA-PEG-DA) on the cationic drug-loaded core (poly(β-amino ester-cholesterol, PAE-Chol) through electrostatic interaction in this study. The charge shielding behaviour of the FPDPCNPs/DTX was confirmed by zeta potential assay. The surface charges of the nanoparticles can change from positive to negative after PEG coating. The IC50 values of FPDPCNPs/DTX was 3.04 times higher than that of PEG “unsheddable” nanoparticles in cytotoxicity experiments. The results of in vivo experiment further showed that FPDPCNPs/DTX had enhanced tumour targeting effect, the tumour inhibition rate of FPDPCNPs/DTX was as high as 81.99%, which was 1.51 times that of free DTX. Under a micro acidic environment and folate receptor (FR)-mediated targeting, FPDPCNPs/DTX contributed to more uptake of DTX by MCF-7 cells. In summary, FPDPCNPs/DTX as a multifunctional nano-drug delivery system provides a promising strategy for efficiently delivering antitumour drugs.

Environmental contaminants modulate transport activity of zebrafish (Danio rerio) multidrug and toxin extrusion protein 3 (Mate3/Slc47a2.1)

Zebrafish Mate3 is one of six co-orthologs of human multidrug and toxin extrusion proteins. It is highly expressed in the kidneys, intestine, testes, and brain of males. Initial interaction studies showed its interaction with xenobiotic compounds, suggesting a role in the efflux of toxic compounds. In this study, we aimed to test various environmental contaminants for their interaction with zebrafish Mate3. We developed a stable zebrafish Mate3 cell line and optimized a high-throughput screening assay using DAPI and ASP+ as fluorescent model substrates. To gain insight into the structure and function of the Mate3 protein and relate these to the results of the DAPI and ASP+ transport measurements, we predicted its 3D structure using the AlphaFold2 algorithm. A 3D structure with high per residue confidence scores with 13 transmembrane segments (TMs) was obtained, with topology and mutual positioning characteristic of the Mate protein family in a shape open to the extracellular part. Molecular docking methods were used to identify DAPI and ASP+ binding sites on the surface and in the center of the protein cavity. Because our kinetics experiments combined with molecular docking indicated that there may be additional active sites in zebrafish Mate3, additional cytotoxicity experiments were performed and highly potent Mate3 interactors were identified from a set of 55 different environmental contaminants. Our results suggest that some of the identified interactors may be of environmental concern, as their interaction with Mate3 could lead to an impairment of its normal efflux function, making fish more sensitive to harmful substances commonly released into the aquatic environment. Finally, the quality of zebrafish Mate3 structures predicted by the AlphaFold2 algorithm opens up the possibility of successfully using this tool for in silico research on transport preferences of other Mate proteins.

Analysis of Targeted Therapy of Parkinson’s Disease with Coloaded Nanoparticles

The key to the treatment of Parkinson’s disease (PD) is delivering an effective amount of drugs into the brain to work, and supplementing the missing dopamine (Dop) in the brain is still the most effective treatment currently. In this research, borneol (Bor) was utilized to promote the drug to enter the brain through the nasal cavity, and lactoferrin (Lf) was utilized as the targeting molecule to modify the nanoparticles (NPs) so that they entered the brain and focused on the lesion site of PD to achieve targeting. They were then evaluated in vivo and in vitro, thus providing the basis for the development of the Lac-Bor/Dop NPs in PD therapy. In the experiment, the particle size of Lac-Bor/Dop NPs prepared by the optimal prescription process was 163.7±15.6 nm, the Dop drug loading was (7.86±1.68) %, and the Zeta potential was (−21.36±3.34) mV. The in vitro release confirmed that the Lac-Bor/Dop NPs had good sustained release characteristics in PBS medium. The cytotoxicity and uptake experiments confirmed that the cytotoxicity of Dop encapsulated in NPs was markedly inferior to that of free Dop (P <0.05). For SH-SY5Y cells and 16HBE cells, Bor and Lf co-modified NPs can promote cell uptake. In vivo animal imaging counts confirmed that the coloaded NPs were capable of synergistic nasal drug delivery to the brain for better brain targeting. Furthermore, a PD model induced by dopaminergic neuron injury induced by unilateral striatal injection of 6-OHDA was constructed in rats and assigned into various groups to demonstrate the therapeutic effect of NPs on PD rats. The results revealed that relative to other groups, the contralateral rotations of rats in the Lac-Bor/Dop NP group were decreased drastically after 20 days of administration (P <0.01), and the levels of Dop and dihydroxyphenylacetic acid (DOPAC) in the injured striatum were increased markedly (P <0.01), demonstrating that the delivery system could achieve excellent PD therapy effects after nasal administration.

Hydrogen Peroxide-Inducible PROTACs for Targeted Protein Degradation in Cancer Cells.

Proteolysis-targeting chimeras (PROTACs) provide a powerful technique to degrade targeted proteins utilizing the cellular ubiquitin-proteasome system. The major concern is the host toxicity resulting from their poor selectivity. Inducible PROTACs responding to exogenous stimulus, such as light, improve their specificity, but it is difficult for photo-activation in deep tissues. Herein, we develop H2 O2 -inducible PROTAC precursors 2/5, which can be activated by endogenous H2 O2 in cancer cells to release the active PROTACs 1/4 to effectively degrade targeted proteins. This results in the intended cytotoxicity towards cancer cells while targeted protein in normal cells remains almost unaffected. The higher Bromodomain-containing protein 4 (BRD4) degradation activity and cytotoxicity of 2 towards cancer cells is mainly due to the higher endogenous concentration of H2 O2 in cancer cells (A549 and H1299), characterized by H2 O2 -responsive fluorescence probe 3. Western blot assays and cytotoxicity experiments demonstrate that 2 degrades BRD4 more effectively and is more cytotoxic in H2 O2 -rich cancer cells than in H2 O2 -deficient normal cells. This method is also extended to estrogen receptor (ER)-PROTAC precursor 5, showing H2 O2 -dependent ER degradation ability. Thus, we establish a novel strategy to induce targeted protein degradation in a H2 O2 -dependent way, which has the potential to improve the selectivity of PROTACs.