A bis-boron boramino acid PET tracer for brain tumor diagnosis.

PURPOSE: Boramino acids are a class of amino acid biomimics that replace the carboxylate group with trifluoroborate and can achieve the 18F-labeled positron emission tomography (PET) and boron neutron capture therapy (BNCT) with identical chemical structure. METHODS: This study reports a trifluoroborate-derived boronophenylalanine (BBPA), a derived boronophenylalanine (BPA) for BNCT, as a promising PET tracer for tumor imaging. RESULTS: Competition inhibition assays in cancer cells suggested the cell accumulation of [18F]BBPA is through large neutral amino acid transporter type-1 (LAT-1). Of note, [18F]BBPA is a pan-cancer probe that shows notable tumor uptake in B16-F10 tumor-bearing mice. In the patients with gliomas and metastatic brain tumors, [18F]BBPA-PET shows good tumor uptake and notable tumor-to-normal brain ratio (T/N ratio, 18.7 ± 5.5, n = 11), higher than common amino acid PET tracers. The [18F]BBPA-PET quantitative parameters exhibited no difference in diverse contrast-enhanced status (P = 0.115-0.687) suggesting the [18F]BBPA uptake was independent from MRI contrast-enhancement. CONCLUSION: This study outlines a clinical trial with [18F]BBPA to achieve higher tumor-specific accumulation for PET, provides a potential technique for brain tumor diagnosis, and might facilitate the BNCT of brain tumors.

Life cycle assessment of a novel tannin-boron association for wood protection.

In these studies of fix boron compounds, associations between tannins and boron (TB) in the form of boric acid appear to be of interest. These TB associations allow the use of boron at very low levels (in compliance with EU restrictions, 2008/58/EC) and limit boron leaching which maintains biological resistance and fire retardant properties. As a consequence, TB wooden products present an extended service life compared to boron compounds alone and were designed to be environmentally-friendly wood protection systems. A follow-up of tannin­boron use identified the environmental impacts using a life cycle assessment (LCA). This LCA was performed on tannin­boron preservative products as well as several industrial preservative-treated timbers and concrete used in the landscape. Cr-containing inorganic salt and an alkaline copper quaternary preservative formulation, as well as concrete, have been used as referential materials to compare the environmental footprint with the tannin­boron treated system. A model was created with life cycle stages used to calculate inputs and outputs during raw material extraction, supplier transportation, manufacturing process, distribution, disposal transportation and processing. Tannin production data were based on Vieira et al. in the field of condensed tannin extraction. However, the extracted tannin in the extraction yield, the inorganic salt, and the process applied are not perfectly comparable with the extraction conditions industrially applied for the Mimosa (Acacia mearnsii) extract which is the major constituent of the TB formulations. The latter is counter-current water extracted without any chemicals or with a limited amount of NaHSO3 or Na2SO3 (at 0.5 % to 1 %) - at a temperature of 70-90 °C. Unfortunately these parameters cannot be elaborated by the LCA program because there is no data available for the production of Na bisulphite or Na bicarbonate in the LCI data used. Other input data were sourced from the ecoinvent v3.8 database. The ReCiPe midpoint method was used to assess the environmental footprint and the CED method was chosen to analyze a general view of the energy-related environmental impacts in the life cycle. Overall, the results demonstrated that tannin­boron preservatives can be regarded as a low-environmental impact formulation. Additionally, an economic analysis of the development of a commercially-viable tannin­boron preservative would now be timely.

The effect of lithium tetraborate as a novel cardioprotective agent after renal ischemia-reperfusion injury

Abstract Epidemiological studies suggest that acute kidney injury has certain effect on myocardial function. In this study, for the first time, we tested a boron compound namely lithium tetraborate an act as an anti-oxidant and anti-inflammatory agent in ischemia-reperfusion injury. For this, we employed an in vivo rat model with kidney ischemia reperfusion injury to evaluate cardiac injury to clarify the mechanisms of lithium tetraborate. The evaluation of cardiac injury through kidney artery occlusion and reperfusion rat model indicated that lithium tetraborate could (1) reduce oxidative stress-induced endothelial dysfunction; (2) attenuate the inflammatory response of cardiac cells; and (3) alleviate the apoptosis and necrosis of myocytes. In summary, lithium tetraborate demonstrates significant therapeutic properties that contribute to the amelioration of cardiac damage, and it could be a promising candidate for future applications in myocardial dysfunction.

Synthesis and biological evaluation of cationic TopFluor cholesterol analogues.

Cholesterol is not only a major component of the cell membrane, but also plays an important role in a wide range of biological processes and pathologies. It is therefore crucial to develop appropriate tools for visualizing intracellular cholesterol transport. Here, we describe new cationic analogues of BODIPY-Cholesterol (TopFluor-Cholesterol, TF-Chol), which combine a positive charge on the sterol side chain and a BODIPY group connected via a C-4 linker. In contrast to TF-Chol, the new analogues TF-1 and TF-3 possessing acetyl groups on the A ring (C-3 position on steroid) internalized much faster and displayed slightly different levels of intracellular localization. Their applicability for cholesterol monitoring was indicated by the fact that they strongly label compartments with accumulated cholesterol in cells carrying a mutation of the Niemann-Pick disease-associated cholesterol transporter, NPC1.

Highly stable organic photothermal agent based on near-infrared-II fluorophores for tumor treatment.

BACKGROUND: The aim to develop a highly stable near-infrared (NIR) photoinduced tumor therapy agent stems from its considerable potential for biological application. Due to its long wavelength, biological imaging exhibits a high signal-to-background ratio, deep tissue penetration and maximum permissible light power, which can minimize damage to an organism during photoinduced tumor therapy. RESULTS: A class of stable NIR-II fluorophores (NIR998, NIR1028, NIR980, NIR1030, and NIR1028-S) based on aza-boron-dipyrromethene (aza-BODIPY) dyes with donor-acceptor-donor structures have been rationally designed and synthesized by harnessing the steric relaxation effect and intramolecular photoinduced electron transfer (IPET). These fluorophores exhibit an intense range of NIR-II emission, large Stokes shift (≥ 100 nm), excellent photothermal conversion performance, and superior stability against photobleaching. Among the NIR-II fluorophores, NIR998 possesses better NIR-II emission and photothermal conversion performance. NIR998 nanoparticles (NIR998 NPs) can be encapsulated by liposomes. NIR998 NPs show superior stability in the presence of light, heat, and reactive oxygen nitrogen species than that of indocyanine green NPs, as well as a higher photothermal conversion ability (η = 50.5%) compared to other photothermal agents. Finally, under the guidance of photothermal imaging, NIR998 NPs have been proven to effectively eliminate tumors via their excellent photothermal conversion performance while presenting negligible cytotoxicity. CONCLUSIONS: Utilizing IPET and the steric relaxation effect can effectively induce NIR-II emission of aza-BODIPY dyes. Stable NIR998 NPs have excellent photothermal conversion performance and negligible dark cytotoxicity, so they have the potential to act as photothermal agents in biological applications.

Mobility shift-based electrophoresis coupled with fluorescent detection enables real-time enzyme analysis of carbohydrate sulfatase activity.

Sulfated carbohydrate metabolism is a fundamental process, which occurs in all domains of life. Carbohydrate sulfatases are enzymes that remove sulfate groups from carbohydrates and are essential to the depolymerisation of complex polysaccharides. Despite their biological importance, carbohydrate sulfatases are poorly studied and challenges remain in accurately assessing the enzymatic activity, specificity and kinetic parameters. Most notably, the separation of desulfated products from sulfated substrates is currently a time-consuming process. In this paper, we describe the development of rapid capillary electrophoresis coupled to substrate fluorescence detection as a high-throughput and facile means of analysing carbohydrate sulfatase activity. The approach has utility for the determination of both kinetic and inhibition parameters and is based on existing microfluidic technology coupled to a new synthetic fluorescent 6S-GlcNAc carbohydrate substrate. Furthermore, we compare this technique, in terms of both time and resources, to high-performance anion exchange chromatography and NMR-based methods, which are the two current 'gold standards' for enzymatic carbohydrate sulfation analysis. Our study clearly demonstrates the advantages of mobility shift assays for the quantification of near real-time carbohydrate desulfation by purified sulfatases, and will support the search for small molecule inhibitors of these disease-associated enzymes.

Oxidative degradation profile studies of tavaborole by a validated stability indicating RP-UPLC method: Isolation and characterization of novel degradant using 2D-NMR and HRMS.

The current research work reports a study on the degradation profile of tavaborole, which is an oxaborole antifungal drug used to treat infections in the toenails. This work also reports the chemical stability of tavaborole in different stress conditions along with the isolation and characterization of degradation products by high-resolution mass spectrometry and two-dimensional nuclear magnetic resonance techniques. A sensitive and reproducible stability-indicating ultra-performance liquid chromatography method was developed and validated for quantification of tavaborole bulk drug in the presence of degradation products. Significant degradation was observed during oxidative stress conditions using H2 O2 . It was observed that the drug was highly unstable under oxidation stress conditions and thus degradation profiles with various oxidizing reagents were studied. One unknown impurity (DP-1) was formed during peroxide degradation, which was isolated by reverse-phase preparative chromatography. The structure of this degradant was characterized by high-resolution mass spectrometry and multidimensional nuclear magnetic resonance techniques. The structure of this novel impurity DP-1 was identified as [4-fluoro-2-(hydroxymethyl)phenol], which was not reported as a degradant in the literature. An Acquity BEH C18 , 100 × 2.1 mm, 1.7 µm column was used to achieve the desired separation within a shorter runtime of 4.0 min. The method was validated for specificity, precision, linearity and accuracy over the concentration range of 5.0-400 µg ml-1 (r2 -0.9999) and limit of quantitation 5.0 µg ml-1 . This method is compatible with LCMS analysis which enables to identify the unknown impurities formed in the process.

Assessment of lipid load in tumor-infiltrating Tregs by flow cytometry.

Regulatory T cells (Tregs), expressing the transcription factor Foxp3, are defined as immunosuppressive cells able to modulate a variety of immune cells in order to avoid unwanted and excessive immune responses; however, in the tumor context, Treg function contribute to inhibit immune surveillance, thus promoting cancer progression. In tumor microenvironment, where the availability of metabolic resources is strongly limited, Tregs are expanded and may exploit different metabolic routes to achieve a metabolic advantage, prevailing over effector cells. In this context an important role of lipid metabolism has been described thanks to the possibility to evaluate the intracellular lipid content selectively in tumor-infiltrating Tregs (TUM-Tregs). Taking into account the heterogeneous and complex build of tumor mass, we set-up a combined protocol that optimizes tumor-infiltrating lymphocytes (TIL) extraction from the tissue through a Percoll density gradient, and assesses ex vivo the lipid load in whole TUM-Treg population, evaluating by flow cytometry the incorporation of an intensely fluorescent lipophilic fluorophore able to specifically stain neutral lipids. This method provides an important advantage compared to the traditional technique based on microscopy, whose lipid level evaluation is limited to a tissue section, and hence may not be representative of the entire population.

Sensing Temperature in Vitro and in Cells Using a BODIPY Molecular Probe.

Boron dipyrromethene (BODIPY) molecular rotors have shown sensitivity toward viscosity, polarity, and temperature. Here, we report a 1,3,5,7-tetramethyl-8-phenyl-BODIPY modified with a polyethylene glycol (PEG) chain, for temperature sensing and live cell imaging. This new PEG-BODIPY dye presents an increase in nonradiative decay as temperature increases, which directly influences its lifetime. This change in lifetime is dependent on changes in both temperature and viscosity at low viscosity values, but is only dependent on temperature at high viscosity values. The dependence of fluorescence lifetime with temperature allows for temperature monitoring in vitro and in cells, with sub degree resolution. When in contact with cells, the PEG-BODIPY spontaneously penetrates and stains the cell but not the nucleus. Furthermore, no significant cell toxicity was found even at 100 µM concentration. Using fluorescence lifetime imaging microscopy (FLIM), we were able to observe the changes in the lifetime of PEG-BODIPY within the cell at different temperatures. The use of FLIM and molecular probes such as PEG-BODIPY can provide important information about cellular temperature and heat dissipation upon medically relevant stimuli, such as radiofrequency ablation and photodynamic therapy.

Isolation and Propagation of Single Inclusion-Derived Chlamydia Using Laser Microdissection.

Other than its routine application for capturing pure cell populations from fixed tissue sections for diverse downstream molecular assays, laser microdissection enables isolation of single live cells. Here we describe a method for the isolation of single Chlamydia trachomatis-infected cells using a laser microdissection system, in which the dissected samples are captured via gravity. Cells infected by C. trachomatis at low multiplicity of infection are marked with the fluorescent Golgi-specific probe BODIPY® FL C5-ceramide, to facilitate identification of the cells with chlamydial inclusions under the microscope. Individual C. trachomatis-infected cells are harvested into separate wells with a pregrown host cell monolayer. Inclusions in harvested cells maturate, and the released elementary bodies infect the host cell monolayer, thus initiating propagation of single inclusion-derived Chlamydia. The method can be used for generation of microbiological clones of C. trachomatis and recovery of transformants and mutants. Isolated single Chlamydia-infected cells can also be examined by diverse downstream molecular assays to reveal unknown features of the Chlamydia replication at a single inclusion level.

Computational Characterization of a Cholesterol-Based Molecular Rotor in Lipid Membranes.

Biophysical properties of cellular membranes critically depend on their content of cholesterol and its interaction with various other lipid species. Cholesterol-dependent friction at the nanoscale can be studied with molecular rotors, whose quantum yield depends on rotational dynamics of functional groups during their excited state lifetime. Here, we present a detailed computational analysis of a phenyl-BODIPY-linked cholesterol based molecular rotor in direct comparison with the well-known TopFluor-cholesterol. We describe a new parametrization strategy of force field parameters for the BODIPY moiety and carry out extensive molecular dynamics simulations of the probe in membranes in the absence or presence of cholesterol. Our study quantifies the extent of membrane perturbation by these probes, analyzes their tilting resistance in the bilayer and derives dynamic properties directly related to the rotor propensity. We show that phenyl-BODIPY-cholesterol bears potential as a cholesterol-dependent molecular rotor to report about microviscosity of sterol-containing model and cell membranes.

Development and validation of a simple method for the extraction and quantification of crisaborole in skin layers.

Crisaborole is a boron compound recently approved by the US Food and Drug Administration as a 2% ointment for the treatment of mild to moderate atopic dermatitis. This work describes a simple method for the quantification of the drug in the skin layers at the end of in-vitro permeation experiments. Chromatographic separation was carried out on a reverse-phase C18 column using a mixture of trifluoroacetic acid 0.05%-acetonitrile (55:45, v/v) as mobile phase, pumped at 1 ml/min. Column temperature was 35°C and UV detection was performed at 250 nm. The method was linear in the range of concentration from 0.06 to 6 µg/ml (R2 = 1) and was selective, precise and accurate. Depending on the solvent used, the LOQ ranged from 0.014 to 0.030 µg/ml and the LOD from 0.005 to 0.010 µg/ml. The extraction from all the skin layers was quantitative. The developed method was successfully tested in an in-vitro permeation study, proving to be an effective tool in the development of new formulations containing crisaborole.

Assay Methods for the Glycosyltransferases Involved in Synthesis of Bacterial Polysaccharides.

Glycans play many important roles in bacterial biology and the complexity of the glycan structures requires biochemical assays in place to help characterize the biosynthetic pathways. Our focus has been on the use of enzymes from pathogens which make molecular mimics of host glycans. We have been examining glycosyltransferases that make strategic linkages in biologically active glycans which can be also exploited for potential therapeutic glycoconjugate synthesis. This chapter will provide details on assays for a variety of bacterial glycosyltransferases that we and others have used for the characterization of pathogen glycoconjugate biosynthetic pathways, and for the in vitro synthesis of human-like glycans produced by bacterial pathogens. The methods presented here should enable other assays to be developed for new pathway characterization.

Introducing the Alba® Primary Packaging Platform. Part 2: Inorganic Extractables Evaluation.

Sensitivity of drugs to one or more elements of the primary packaging is a serious concern for the pharmaceutical industry. Biologics in particular are highly sensitive, leading to a higher risk of incompatibility and stability test failure as worst-case scenario.This potential incompatibility-and the consequent formulation instability due to the interactions between the drug and the primary container surface-may have multiple causes: the intrinsic nature of the container surface, leachables coming from the materials used, substances coming from the production process, or silicone oil droplets or other particles.The Alba primary packaging platform was designed to have the same interface between the drug and the glass container surface on the different primary packaging containers in order to minimize the emergence of instabilities at later stages of formulation development. Alba containers are internally treated with an innovative cross-linked coating based on silicone oil lubricant, and the additional rubber components have been selected to minimize the possible differences between the container typologies.This paper shows in great detail the reduction of the inorganic extractables released and the comparability of the performances of the different containers obtained using Alba technology.The improvement has been demonstrated by stressing the containers with different extract solutions; Alba-coated containers show a strong reduction of inorganic extractables and of corrosion degree compared to spray-on siliconized and bulk products. The containers included in the Alba platform present comparable results, and this represents a strong advantage during the drug formulation development by facilitating the transition from one container to another.LAY ABSTRACT: The sensitivity of drugs to one or more elements of the primary packaging is a serious concern for the pharmaceutical industry. Biologics in particular are highly sensitive, leading to a higher risk of incompatibility and stability test failure worst-case scenario.This potential incompatibility-and the consequent formulation instability due to the interactions between the drug and the primary container surface-may have multiple causes: the intrinsic nature of the container surface, leachables coming from the materials used, substances coming from the production process, or silicone oil droplets or other particles.The Alba primary packaging platform was designed to minimize these problems associated with the interaction between the drug and its primary packaging. This paper shows in great detail and with robust data the inorganic extractables release reduction and the delamination risk mitigation obtained using the Alba technology.

Far-Red Photoactivatable BODIPYs for the Super-Resolution Imaging of Live Cells.

The photoinduced disconnection of an oxazine heterocycle from a borondipyrromethene (BODIPY) chromophore activates bright far-red fluorescence. The high brightness of the product and the lack of autofluorescence in this spectral region allow its detection at the single-molecule level within the organelles of live cells. Indeed, these photoactivatable fluorophores localize in lysosomal compartments and remain covalently immobilized within these organelles. The suppression of diffusion allows the reiterative reconstruction of subdiffraction images and the visualization of the labeled organelles with excellent localization precision. Thus, the combination of photochemical, photophysical and structural properties designed into our fluorophores enable the visualization of live cells with a spatial resolution that is inaccessible to conventional fluorescence imaging.

Assessing and Mitigating the Hazard Potential of Two-Dimensional Materials.

The family of two-dimensional (2D) materials is comprised of a continually expanding palette of unique compositions and properties with potential applications in electronics, optoelectronics, energy capture and storage, catalysis, and nanomedicine. To accelerate the implementation of 2D materials in widely disseminated technologies, human health and environmental implications need to be addressed. While extensive research has focused on assessing the toxicity and environmental fate of graphene and related carbon nanomaterials, the potential hazards of other 2D materials have only recently begun to be explored. Herein, the toxicity and environmental fate of postcarbon 2D materials, such as transition metal dichalcogenides, hexagonal boron nitride, and black phosphorus, are reviewed as a function of their preparation methods and surface functionalization. Specifically, we delineate how the hazard potential of 2D materials is directly related to structural parameters and physicochemical properties and how experimental design is critical to the accurate elucidation of the underlying toxicological mechanisms. Finally, a multidisciplinary approach for streamlining the hazard assessment of emerging 2D materials is outlined, thereby providing a pathway for accelerating their safe use in a range of technologically relevant contexts.

Development and Validation of an HPLC-UV Method to Quantify Tavaborole During in Vitro Transungual Permeation Studies.

A selective and rapid reversed-phase HPLC-UV method was developed and validated to quantify tavaborole (TAV; AN2690) in biological samples, i.e., in receiving phase and in bovine hoof membrane extract derived from in vitro transungual permeation studies. A simple solid-liquid extraction procedure was used to recover the drug from the bovine hoof slices. TAV chromatographic separation was achieved on a Luna PFP column (150 × 4.6 mm, 5 µm) using a mobile phase consisting of a 70% phosphoric acid solution (10 mM, pH 2.0) with 30% acetonitrile. The detection wavelength was set to 220 nm using a UV detector. The method exhibited good linearity in the calibration ranges, which were 0.5-8.0 and 0.03-2.5 µg/mL for the receiving phase and hoof membranes, respectively. The obtained LOD and LOQ values were 0.023 and 0.069 µg/mL, respectively, for the receiving phase and 0.0024 and 0.007 µg/mL for the bovine hoof membrane extracts. In all cases, the CV for intraday and interday precision was widely below the limit of 2%, demonstrating good precision. The analytical method described was sensitive, precise, linear, and accurate and could be applicable for clinical and bioanalytical studies as an alternative to other analytical methods, which are quite expensive and not always available in research laboratories.

Mechanically-competent and cytocompatible polycaprolactone-borophosphosilicate hybrid biomaterials.

Organic-inorganic class II hybrid materials have domain sizes at the molecular level and chemical bonding between the organic and inorganic phases. We have previously reported the synthesis of class II hybrid biomaterials from alkoxysilane-functionalized polycaprolactone (PCL) and borophosphosilicate (B2O3-P2O5-SiO2) glass (BPSG) through a non-aqueous sol-gel process. In the present study, the mechanical properties and degradability of these PCL/BPSG hybrid biomaterials were studied and compared to those of their conventional composite counterparts. The compressive strength, modulus and toughness of the hybrid biomaterials were significantly greater compared to the conventional composites, likely due to the covalent bonding between the organic and inorganic phases. A hybrid biomaterial (50wt% PCL and 50wt% BPSG) exhibited compressive strength, modulus and toughness values of 32.2 ± 3.5MPa, 573 ± 85MPa and 1.54 ± 0.03MPa, respectively; whereas the values for composite of similar composition were 18.8 ± 1.6MPa, 275 ± 28MPa and 0.76 ± 0.03MPa, respectively. Degradation in phosphate-buffered saline was slower for hybrid biomaterials compared to their composite counterparts. Thus, these hybrid materials possess superior mechanical properties and more controlled degradation characteristics compared to their corresponding conventional composites. To assess in vitro cytocompatibility, MC3T3-E1 pre-osteoblastic cells were seeded onto the surfaces of hybrid biomaterials and polycaprolactone (control). Compared to polycaprolactone, cells on the hybrid material displayed enhanced spreading, focal adhesion formation, and cell number, consistent with excellent cytocompatibility. Thus, based on their mechanical properties, degradability and cytocompatibility, these novel biomaterials have potential for use as scaffolds in bone tissue engineering and related applications.

Preparation of a Trp-BODIPY fluorogenic amino acid to label peptides for enhanced live-cell fluorescence imaging.

Fluorescent peptides are valuable tools for live-cell imaging because of the high specificity of peptide sequences for their biomolecular targets. When preparing fluorescent versions of peptides, labels must be introduced at appropriate positions in the sequences to provide suitable reporters while avoiding any impairment of the molecular recognition properties of the peptides. This protocol describes the preparation of the tryptophan (Trp)-based fluorogenic amino acid Fmoc-Trp(C2-BODIPY)-OH and its incorporation into peptides for live-cell fluorescence imaging-an approach that is applicable to most peptide sequences. Fmoc-Trp(C2-BODIPY)-OH contains a BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) fluorogenic core, which works as an environmentally sensitive fluorophore, showing high fluorescence in lipophilic conditions. It is attached to Trp via a spacer-free C-C linkage, resulting in a labeled amino acid that can mimic the molecular interactions of Trp, enabling wash-free imaging. This protocol covers the chemical synthesis of the fluorogenic amino acid Fmoc-Trp(C2-BODIPY)-OH (3-4 d), the preparation of the labeled antimicrobial peptide BODIPY-cPAF26 by solid-phase synthesis (6-7 d) and its spectral and biological characterization as a live-cell imaging probe for different fungal pathogens. As an example, we include a procedure for using BODIPY-cPAF26 for wash-free imaging of fungal pathogens, including real-time visualization of Aspergillus fumigatus (5 d for culturing, 1-2 d for imaging).

Structural, electronic and spectral properties of carborane-containing boron dipyrromethenes (BODIPYs): A first-principles study.

In this work, we reported the geometrical structures, electronic and spectral properties of the carborane-containing BODIPYs complexes using the density functional theory calculations. In two structures, the calculated main bond lengths and bond angels of structural framework are consistent with X-ray experiment, and the two BODIPYs complexes are thermodynamically and kinetically stable. The strongest DOS band is mainly dominated by the BB and BH σ-bonds of carborane fragment, whereas the π-type MOs on the pyrromethene fragment contribute to the high-energy DOS bands. Analysis of the AdNDP chemical bonding indicates that the carborane cage can be stabilized by eleven delocalized 3c2e and two delocalized 4c2e σ-bonds, while the pyrromethene fragment corresponds to five delocalized 3c2e π-bonds. In addition, the main characteristic peaks of the two simulated IR spectra for the BODIPYs complexes are properly assigned. Hopefully, all these results will be helpful for understanding the electronic structures, and further stimulate the study on the biological and medical applications.