Fourier transform infrared spectroscopy (FTIR) characterization of the interaction of anti-cancer photosensitizers with dendrimers

Interaction study of aflatoxin M1 with milk proteins using ATR-FTIR

Aflatoxin M1 (AFM1) is a metabolite of carcinogenic aflatoxin B1 (AFB1) and appears in milk of dairy animals on ingestion of feed contaminated with AFB1. It has been reported to have affinity towards milk proteins, the exact mechanism of which is still unknown. In the present study, ATR-FTIR coupled with chemometrics is utilized to understand AFM1 interaction with milk proteins. The second order derivative spectra of the spectral window 1700-1600 cm-1 confirms the affinity of AFM1 towards milk proteins. The results of principal component analysis suggested that spectral window of 1700-1600 cm-1 is informative and provides an indication of the conformational changes brought by AFM1 in the secondary structure of milk proteins.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05587-x.

Polymeric Dendrimers as Nanocarrier Vectors for Neurotheranostics

Dendrimers are polymers with well-defined 3D branched structures that are vastly utilized in various neurotheranostics and biomedical applications, particularly as nanocarrier vectors. Imaging agents can be loaded into dendrimers to improve the accuracy of diagnostic imaging processes. Likewise, combining pharmaceutical agents and anticancer drugs with dendrimers can enhance their solubility, biocompatibility, and efficiency. Practically, by modifying ligands on the surface of dendrimers, effective therapeutic and diagnostic platforms can be constructed and implemented for targeted delivery. Dendrimer-based nanocarriers also show great potential in gene delivery. Since enzymes can degrade genetic materials during their blood circulation, dendrimers exhibit promising packaging and delivery alternatives, particularly for central nervous system (CNS) treatments. The DNA and RNA encapsulated in dendrimers represented by polyamidoamine that are used for targeted brain delivery, via chemical-structural adjustments and appropriate generation, significantly improve the correlation between transfection efficiency and cytotoxicity. This article reports a comprehensive review of dendrimers' structures, synthesis processes, and biological applications. Recent progress in diagnostic imaging processes and therapeutic applications for cancers and other CNS diseases are presented. Potential challenges and future directions in the development of dendrimers, which provide the theoretical basis for their broader applications in healthcare, are also discussed.

Ultrasmall organosilica nanoparticles with strong solid-state fluorescence for multifunctional applications

INTRODUCTION

Organosilica nanoparticles (ONs), which are a new type of photoluminescent nanomaterial (PM) with excellent biocompatibility, have caught more attention in recent years. However, their applications are significantly impeded by the complicated preparation process, poor photostability, and especially aggregation-induced quenching.

OBJECTIVES

The present study was aimed to design and prepare solid-state fluorescent ONs to avoid aggregation-induced quenching effect. In addition, the uses of ONs for fingerprint detection, white light-emitting diodes (WLEDs) and lysosome-targetable cellular imaging were demonstrated.

METHODS

Here, for the first time, we designed and prepared novel solid-state fluorescent ultrasmall ONs with orange-emitting photoluminescence via a one-step hydrothermal method.

RESULTS

The prepared solid-state fluorescent ONs could be successfully employed in fingerprint detection, WLEDs fabrication and cellular imaging. Intriguingly, the ultrasmall ONs specifically localized to lysosomes rather than other subcellular organelles across distinct cell lines, including cancer cells and noncancerous cells.

CONCLUSION

Collectively, these data showed that the new ONs presented in this study could be ideal candidates for PMs in biological and photoelectric applications.

Orthogonal nanoarchitectonics of M13 phage for receptor targeted anticancer photodynamic therapy

Photodynamic therapy (PDT) represents a promising therapeutic modality for cancer. Here we used an orthogonal nanoarchitectonics approach (genetic/chemical) to engineer M13 bacteriophages as targeted vectors for efficient photodynamic killing of cancer cells. M13 was genetically refactored to display on the phage tip a peptide (SYPIPDT) able to bind the epidermal growth factor receptor (EGFR). The refactored M13_EGFR phages demonstrated EGFR-targeted tropism and were internalized by A431 cancer cells, that overexpress EGFR. Using an orthogonal approach to the genetic display, M13_EGFR phages were then chemically modified, conjugating hundreds of Rose Bengal (RB) photosensitizing molecules on the capsid surface, without affecting the selective recognition of the SYPIPDT peptides. Upon internalization, the M13_EGFR-RB derivatives generated intracellularly reactive oxygen species, activated by an ultralow intensity white light irradiation. The killing activity of cancer cells is observed at picomolar concentrations of the M13_EGFR phage.

Noncovalent Interactions with PAMAM and PPI Dendrimers Promote the Cellular Uptake and Photodynamic Activity of Rose Bengal: The Role of the Dendrimer Structure

Rose bengal is an anionic dye considered as a potential photosensitizer for anticancer photodynamic therapy. The clinical utility of rose bengal is hampered by its short half-life, limited transmembrane transport, aggregation, and self-quenching; consequently, efficient drug carriers that overcome these obstacles are urgently required. In this study, we performed multilevel in vitro and in silico characterization of interactions between rose bengal and cationic poly(amidoamine) (PAMAM) and poly(propyleneimine) (PPI) dendrimers of the third and fourth generation and assessed the ability of the resultant complexes to modulate the photosensitizing properties of the drug. We focused on explaining the molecular basis of this phenomenon and proved that the generation- and structure-dependent binding of the dye by the dendrimers increases the cellular uptake and production of singlet oxygen and intracellular reactive oxygen species, leading to an increase in phototoxicity. We conclude that the application of dendrimer carriers could enable the design of efficient photodynamic therapies based on rose bengal.

DENDRIMERS IN ANTICANCER TARGETED DRUG DELIVERY: ACCOMPLISHMENTS, CHALLENGES AND DIRECTIONS FOR FUTURE

Dendrimers are nanoparticles with unique features including globular 3D shape and nanometer size. The availability of numerous terminal functional groups and modifiable surface engineering permit modification of dendrimer surface with several therapeutic agents, diagnostic moieties and targeting substances.

The aim. To enlighten the readers regarding design, development, limitations, challenges and future directions regarding anticancer bio-dendrimers.

Materials and methods. The data base was represented by such systems as Medline, Cochrane Central Register of Controlled Trials, Scopus, Web of Science Core Collection, PubMed. gov, Google-Academy. A search was carried out for the following keywords and combinations: Polypropylene imine (PPI); Poly-L-lysine (PLL); polyamidoamine (PAMAM); cancer; drug delivery; dendrimers.

Results. High encapsulation of drug and effective passive targeting are also among their therapeutic uses. Herein, we have described latest developments in chemotherapeutic delivery of drugs by dendrimers. For the most part, the potential and efficacy of dendrimers are anticipated to have considerable progressive effect on drug targeting and delivery.

Conclusion. The newest discoveries have shown that the dendritic nanocarriers have many unique features that endorse more research and development.

In Search of a Phosphorus Dendrimer-Based Carrier of Rose Bengal: Tyramine Linker Limits Fluorescent and Phototoxic Properties of a Photosensitizer

Photodynamic therapy (PDT) is a skin cancer treatment alternative to chemotherapy and radiotherapy. This method exploits three elements: a phototoxic compound (photosensitizer), light source and oxygen. Upon irradiation by light of a specific wavelength, the photosensitizer generates reactive oxygen species triggering the cascade of reactions leading to cell death. The positive therapeutic effect of PDT may be limited due to low solubility, low tumor specificity and inefficient cellular uptake of photosensitizers. A promising approach to overcome these obstacles involves the use of nanocarrier systems. The aim of this initial study was to determine the potential of the application of phosphorus dendrimers as carriers of a photosensitizer—rose bengal (RB). The primary goal involved the synthesis and in vitro studies of covalent drug–dendrimer conjugates. Our approach allowed us to obtain RB–dendrimer conjugates with the use of tyramine as an aromatic linker between the carrier and the drug. The compounds were characterized by FT-IR, ¹H NMR, ¹³C NMR, ³¹P NMR, size and zeta potential measurements and spectrofluorimetric analysis. The dialysis to check the drug release from the conjugate, flow cytometry to specify intracellular uptake, and singlet oxygen generation assay were also applied. Finally, we used MTT assay to determine the biological activity of the tested compounds. The results of our experiments indicate that the conjugation of RB to phosphorus dendrimers via the tyramine linker decreases photodynamic activity of RB.

Electrospun Nanofibers With pH-Responsive Coatings for Control of Release Kinetics

Functional and stimuli-responsive nanofibers with an enhanced surface area/volume ratio provide controlled and triggered drug release with higher efficacy. In this study, chemotherapeutic agent Rose Bengal (RB) (4,5,6,7-tetrachloro-2', 4',5',7'-tetraiodofluoresceindisodium)-loaded water-soluble polyvinyl alcohol (PVA) nanofibers were synthesized by using the electrospinning method. A thin layer of poly(4-vinylpyridine-co-ethylene glycol dimethacrylate) p(4VP-co-EGDMA) was deposited on the RB-loaded nanofibers (PVA-RB) via initiated chemical vapor deposition (iCVD), coating the fiber surfaces to provide controllable solubility and pH response to the nanofibers. The uncoated and [p(4VP-co-EGDMA)-PVA] coated PVA-RB nanofiber mats were studied at different pH values to analyze their degradation and drug release profiles. The coated nanofibers demonstrated high stability at neutral and basic pH values for long incubation durations of 72 h, whereas the uncoated nanofibers dissolved in <2 h. The drug release studies showed that the RB release from coated PVA-RB nanofibers was higher at neutral and basic pH values, and proportional to the pH of the solution, whereas the degradation and RB release rates from the uncoated PVA-RB nanofibers were significantly higher and did not depend on the pH of environment. Further analysis of the release kinetics using the Peppas model showed that while polymer swelling and dissolution were the dominant mechanisms for the uncoated nanofibers, for the coated nanofibers, Fickian diffusion was the dominant release mechanism. The biocompatibility and therapeutic efficiency of the coated PVA-RB nanofibers against brain cancer was investigated on glioblastoma multiforme cancer cells (U87MG). The coated PVA nanofibers were observed to be highly biocompatible, and they significantly stimulated the ROS production in cells, increasing apoptosis. These promising results confirmed the therapeutic activity of the coated PVA-RB nanofibers on brain cancer cells, and encouraged their further evaluation as drug carrier structures in brain cancer treatment.

A One Pot Method for Preparing an Antibacterial Superabsorbent Hydrogel with a Semi-IPN Structure Based on Tara Gum and Polyquaternium-7

An antibacterial superabsorbent polymer was prepared by graft polymerization of acrylic acid onto tara gum polysaccharide, by adding N,N-dimethyl-N-2-propenyl-2-propen-1-aminium chloride and a polymer with 2-propenamide (polyquaternium-7, PQ7) as an antibacterial agent. The effects of the amount of PQ7 in the hydrogel on its swelling ratio were investigated and maximum swelling ratios of 712 g/g and 68 g/g, in distilled water and 0.9 wt % NaCl solution were attained with 0.5 g PQ7 per gram of tara gum. The superabsorbent hydrogel was characterized by using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and thermal gravimetric analysis. The results showed that poly (acrylic acid) was successfully grafted onto tara gum and a three-dimensional network structure formed with PQ7 chains penetrated in the networks. The antibacterial properties of these superabsorbent hydrogels against Staphylococcus aureus and Escherichia coli improved with increasing PQ7 content. This study demonstrates a method of preparing novel functional superabsorbent hydrogels.

Magnetic-luminescent cerium-doped gadolinium aluminum garnet nanoparticles for simultaneous imaging and photodynamic therapy of cancer cells

Nanoparticle (NP) and photosensitizer (PS) conjugates capable of X-ray photodynamic therapy (X-PDT) are a research focus due to their potential applications in cancer treatment. Combined with X-PDT, appropriate imaging properties of the nanocomposite will make it suitable for theranostics of deep lying tumors. In this work, we describe the development of magnetic-luminescent Gd_2.98Ce_0.02Al₅O₁₂ nanoparticles (GAG) coated with mesoporous silica (mSiO₂) and loaded with rose bengal (RB) to yield a nanocomposite GAG@mSiO₂@RB capable of X-PDT. GAG nanoparticles were synthesized using the sol-gel method. The synthesized GAG nanoparticles showed a strong visible yellow emission with a quantum yield of ∼32%. Moreover, the broad emission spectra of GAG nanoparticles centered at 585 nm showed a good overlap with the absorption of RB. Upon irradiation with X-rays (55 KV), the GAG@mSiO₂@RB nanocomposite produced significantly higher singlet oxygen compared with RB alone, as confirmed by the 1,2-diphenylisobenzofuran (DPBF) assay. The developed GAG@mSiO₂@RB nanocomposite significantly reduced the viability of human breast cancer (MDA-MB-231) cells upon irradiation with blue light (λ = 470 nm). The calculated LC₅₀ of GAG@mSiO₂@RB nanocomposites were 26.69, 11.2, and 6.56 µg/mL at a dose of ∼0.16, 0.33 and 0.5 J/cm², respectively. Moreover, the nanocomposite showed paramagnetic properties with high magnetic mass susceptibility which are useful for high contrast T₁ weighted magnetic resonance imaging (MRI). Together with X-PDT, the paramagnetic properties of the proposed GAG@mSiO₂@RB nanocomposite system are promising for their future application in simultaneous detection and treatment of deep-lying tumors.

Rose Bengal attached and dextran coated gadolinium oxide nanoparticles for potential diagnostic imaging applications

We report here, reverse micelle mediated synthesis of multifunctional dextran (dex) coated Gd₂O₃ nanoparticles (NPs) carrying rose bengal (RB) dye for magnetic resonance and optical imaging. The diameter of these RB attached dex coated Gd₂O₃ NPs (Gd-dex-RB NPs) was found to be ~17 nm as measured by TEM. NMR line broadening effect on the surrounding water protons affirmed the paramagnetic nature of these NPs. Optical properties of Gd-dex-RB NPs were validated by UV-Vis and fluorescence spectroscopy. Time dependent release profile of RB from NPs at two different pH of 7.4 and 5.0 revealed that these NPs behave as slow releasing system. In-vitro study revealed that NPs are efficiently taken up by cells and show optical activity in cellular environment. In vitro cell viability (SRB) assay was performed on cancerous (A-549, U-87) and normal (HEK-293) cell lines, showed the absence of cytotoxic effect of Gd-dex-RB NPs. Therefore, such multifunctional NPs can be efficiently used for bio-imaging and optical tracking.

Cationic Phosphorus Dendrimer Enhances Photodynamic Activity of Rose Bengal against Basal Cell Carcinoma Cell Lines

In the last couple of decades, photodynamic therapy emerged as a useful tool in the treatment of basal cell carcinoma. However, it still meets limitations due to unfavorable properties of photosensitizers such as poor solubility or lack of selectivity. Dendrimers, polymers widely studied in biomedical field, may play a role as photosensitizer carriers and improve the efficacy of photodynamic treatment. Here, we describe the evaluation of an electrostatic complex of cationic phosphorus dendrimer and rose bengal in such aspects as singlet oxygen production, cellular uptake, and phototoxicity against three basal cell carcinoma cell lines. Rose bengal-cationic dendrimer complex in molar ratio 5:1 was compared to free rose bengal. Obtained results showed that the singlet oxygen production in aqueous medium was significantly higher for the complex than for free rose bengal. The cellular uptake of the complex was 2-7-fold higher compared to a free photosensitizer. Importantly, rose bengal, rose bengal-dendrimer complex, and dendrimer itself showed no dark toxicity against all three cell lines. Moreover, we observed that phototoxicity of the complex was remarkably enhanced presumably due to high cellular uptake. On the basis of the obtained results, we conclude that rose bengal-cationic dendrimer complex has a potential in photodynamic treatment of basal cell carcinoma.

Complexing Methylene Blue with Phosphorus Dendrimers to Increase Photodynamic Activity

The efficiency of photodynamic therapy is limited mainly due to low selectivity, unfavorable biodistribution of photosensitizers, and long-lasting skin sensitivity to light. However, drug delivery systems based on nanoparticles may overcome the limitations mentioned above. Among others, dendrimers are particularly attractive as carriers, because of their globular architecture and high loading capacity. The goal of the study was to check whether an anionic phosphorus dendrimer is suitable as a carrier of a photosensitizer-methylene blue (MB). As a biological model, basal cell carcinoma cell lines were used. We checked the influence of the MB complexation on its singlet oxygen production ability using a commercial fluorescence probe. Next, cellular uptake, phototoxicity, reactive oxygen species (ROS) generation, and cell death were investigated. The MB-anionic dendrimer complex (MB-1an) was found to generate less singlet oxygen; however, the complex showed higher cellular uptake and phototoxicity against basal cell carcinoma cell lines, which was accompanied with enhanced ROS production. Owing to the obtained results, we conclude that the photodynamic activity of MB complexed with an anionic dendrimer is higher than free MB against basal cell carcinoma cell lines.

Interaction between dendrimers and regulatory proteins. Comparison of effects of carbosilane and carbosilane–viologen–phosphorus dendrimers

For nanoparticles to be used successfully in biomedical application, their interactions with biological fluids need to be investigated, in which they will react with proteins and other macromolecules.